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[v4,0/3] Input: Add TouchNetix axiom touchscreen driver

Message ID 20231204140505.2838916-1-kamel.bouhara@bootlin.com
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Series Input: Add TouchNetix axiom touchscreen driver | expand

Message

Kamel BOUHARA Dec. 4, 2023, 2:05 p.m. UTC
Add a new driver for the TouchNetix's axiom family of
touchscreen controller. This driver only support i2c
and can be later adapted for SPI and USB support.

---
Changes in v2:
 - Add device tree binding documentation
 - Move core functions in axiom_i2c as we only care about i2c support now
 - Use static function when required
 - Use syntax dev_err_probe()
 - Add an hardware based reset

Changes in v3:
 - Remove irq-gpios property in dt-binding
 - Use a generic node name
 - Fix issues reported in https://lore.kernel.org/oe-kbuild-all/202310100300.oAC2M62R-lkp@intel.com/

Changes in v4:
 - Cleanup unused headers and macros
 - Use standard kernel type
 - Namespace structures and functions
 - Use packed struct when possible to avoid bitfield operators
 - Fix missing break when address is found in axiom_populate_target_address()
 - Split reads in two steps for the reports, first length then report
   itself so we only read required bytes
 - Get poll-interval from devicetree
 - Add VDDI/VDDA regulators
 - Add a startup delay of 110 ms required after VDDA/VDDI is applied
 - Remove axiom_i2c_write() as it is no more used

Kamel Bouhara (3):
  dt-bindings: vendor-prefixes: Add TouchNetix AS
  dt-bindings: input: Add TouchNetix axiom touchscreen
  Input: Add TouchNetix axiom i2c touchscreen driver

 .../input/touchscreen/touchnetix,ax54a.yaml   |  56 ++
 .../devicetree/bindings/vendor-prefixes.yaml  |   2 +
 MAINTAINERS                                   |   7 +
 drivers/input/touchscreen/Kconfig             |  12 +
 drivers/input/touchscreen/Makefile            |   1 +
 drivers/input/touchscreen/touchnetix_axiom.c  | 675 ++++++++++++++++++
 6 files changed, 753 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/input/touchscreen/touchnetix,ax54a.yaml
 create mode 100644 drivers/input/touchscreen/touchnetix_axiom.c

--
2.25.1

Comments

POPESCU Catalin Dec. 4, 2023, 3:09 p.m. UTC | #1
On 04.12.23 15:05, Kamel Bouhara wrote:
> This email is not from Hexagon’s Office 365 instance. Please be careful while clicking links, opening attachments, or replying to this email.
>
>
> Add a new driver for the TouchNetix's axiom family of
> touchscreen controllers. This driver only supports i2c
> and can be later adapted for SPI and USB support.
>
> Signed-off-by: Kamel Bouhara <kamel.bouhara@bootlin.com>
> ---
>   MAINTAINERS                                  |   1 +
>   drivers/input/touchscreen/Kconfig            |  12 +
>   drivers/input/touchscreen/Makefile           |   1 +
>   drivers/input/touchscreen/touchnetix_axiom.c | 675 +++++++++++++++++++
>   4 files changed, 689 insertions(+)
>   create mode 100644 drivers/input/touchscreen/touchnetix_axiom.c
>
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 4752d8436dbb..337ddac6c74b 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -21436,6 +21436,7 @@ M:      Kamel Bouhara <kamel.bouhara@bootlin.com>
>   L:     linux-input@vger.kernel.org
>   S:     Maintained
>   F:     Documentation/devicetree/bindings/input/touchscreen/touchnetix,ax54a.yaml
> +F:     drivers/input/touchscreen/touchnetix_axiom.c
>
>   THUNDERBOLT DMA TRAFFIC TEST DRIVER
>   M:     Isaac Hazan <isaac.hazan@intel.com>
> diff --git a/drivers/input/touchscreen/Kconfig b/drivers/input/touchscreen/Kconfig
> index e3e2324547b9..f36bee8d8696 100644
> --- a/drivers/input/touchscreen/Kconfig
> +++ b/drivers/input/touchscreen/Kconfig
> @@ -803,6 +803,18 @@ config TOUCHSCREEN_MIGOR
>            To compile this driver as a module, choose M here: the
>            module will be called migor_ts.
>
> +config TOUCHSCREEN_TOUCHNETIX_AXIOM
> +       tristate "TouchNetix AXIOM based touchscreen controllers"
> +       depends on I2C
> +       help
> +         Say Y here if you have a axiom touchscreen connected to
> +         your system.
> +
> +         If unsure, say N.
> +
> +         To compile this driver as a module, choose M here: the
> +         module will be called axiom.
> +
>   config TOUCHSCREEN_TOUCHRIGHT
>          tristate "Touchright serial touchscreen"
>          select SERIO
> diff --git a/drivers/input/touchscreen/Makefile b/drivers/input/touchscreen/Makefile
> index 62bd24f3ac8e..8e32a2df5e18 100644
> --- a/drivers/input/touchscreen/Makefile
> +++ b/drivers/input/touchscreen/Makefile
> @@ -88,6 +88,7 @@ obj-$(CONFIG_TOUCHSCREEN_SUR40)               += sur40.o
>   obj-$(CONFIG_TOUCHSCREEN_SURFACE3_SPI) += surface3_spi.o
>   obj-$(CONFIG_TOUCHSCREEN_TI_AM335X_TSC)        += ti_am335x_tsc.o
>   obj-$(CONFIG_TOUCHSCREEN_TOUCHIT213)   += touchit213.o
> +obj-$(CONFIG_TOUCHSCREEN_TOUCHNETIX_AXIOM)     += touchnetix_axiom.o
>   obj-$(CONFIG_TOUCHSCREEN_TOUCHRIGHT)   += touchright.o
>   obj-$(CONFIG_TOUCHSCREEN_TOUCHWIN)     += touchwin.o
>   obj-$(CONFIG_TOUCHSCREEN_TS4800)       += ts4800-ts.o
> diff --git a/drivers/input/touchscreen/touchnetix_axiom.c b/drivers/input/touchscreen/touchnetix_axiom.c
> new file mode 100644
> index 000000000000..9783e89f9e3a
> --- /dev/null
> +++ b/drivers/input/touchscreen/touchnetix_axiom.c
> @@ -0,0 +1,675 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * TouchNetix axiom Touchscreen Driver
> + *
> + * Copyright (C) 2020-2023 TouchNetix Ltd.
> + *
> + * Author(s): Bart Prescott <bartp@baasheep.co.uk>
> + *            Pedro Torruella <pedro.torruella@touchnetix.com>
> + *            Mark Satterthwaite <mark.satterthwaite@touchnetix.com>
> + *            Hannah Rossiter <hannah.rossiter@touchnetix.com>
> + *            Kamel Bouhara <kamel.bouhara@bootlin.com>
> + *
> + */
> +#include <linux/bitfield.h>
> +#include <linux/crc16.h>
> +#include <linux/delay.h>
> +#include <linux/device.h>
> +#include <linux/gpio/consumer.h>
> +#include <linux/i2c.h>
> +#include <linux/input.h>
> +#include <linux/input/mt.h>
> +#include <linux/interrupt.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +
> +#define AXIOM_PROX_LEVEL               -128
> +/*
> + * Register group u31 has 2 pages for usage table entries.
> + */
> +#define AXIOM_U31_MAX_USAGES           ((2 * AXIOM_COMMS_PAGE_SIZE) / AXIOM_U31_BYTES_PER_USAGE)
> +#define AXIOM_U31_BYTES_PER_USAGE      6
> +#define AXIOM_U31_PAGE0_LENGTH         0x0C
> +#define AXIOM_U31_BOOTMODE_MASK                BIT(7)
> +#define AXIOM_U31_DEVID_MASK           GENMASK(14, 0)
> +
> +#define AXIOM_CMD_HEADER_READ_MASK     BIT(15)
> +#define AXIOM_U41_MAX_TARGETS          10
> +
> +#define AXIOM_U46_AUX_CHANNELS         4
> +#define AXIOM_U46_AUX_MASK             GENMASK(11, 0)
> +
> +#define AXIOM_COMMS_MAX_USAGE_PAGES    3
> +#define AXIOM_COMMS_PAGE_SIZE          256
> +#define AXIOM_COMMS_REPORT_LEN_MASK    GENMASK(6, 0)
> +
> +#define AXIOM_REPORT_USAGE_ID          0x34
> +#define AXIOM_DEVINFO_USAGE_ID         0x31
> +#define AXIOM_USAGE_2HB_REPORT_ID      0x01
> +#define AXIOM_USAGE_2AUX_REPORT_ID     0x46
> +#define AXIOM_USAGE_2DCTS_REPORT_ID    0x41
> +
> +#define AXIOM_PAGE_OFFSET_MASK         GENMASK(6, 0)
> +
> +struct axiom_devinfo {
> +       u16 device_id;
> +       u8 fw_minor;
> +       u8 fw_major;
> +       u8 fw_info_extra;
> +       u8 tcp_revision;
> +       u8 bootloader_fw_minor;
> +       u8 bootloader_fw_major;
> +       u16 jedec_id;
> +       u8 num_usages;
> +} __packed;
> +
> +/*
> + * Describes parameters of a specific usage, essentially a single element of
> + * the "Usage Table"
> + */
> +struct axiom_usage_entry {
> +       u8 id;
> +       u8 is_report;
> +       u8 start_page;
> +       u8 num_pages;
> +};
> +
> +/*
> + * Represents state of a touch or target when detected prior a touch (eg.
> + * hover or proximity events).
> + */
> +enum axiom_target_state {
> +       AXIOM_TARGET_STATE_NOT_PRESENT = 0,
> +       AXIOM_TARGET_STATE_PROX = 1,
> +       AXIOM_TARGET_STATE_HOVER = 2,
> +       AXIOM_TARGET_STATE_TOUCHING = 3,
> +};
> +
> +struct axiom_u41_target {
> +       enum axiom_target_state state;
> +       u16 x;
> +       u16 y;
> +       s8 z;
> +       bool insert;
> +       bool touch;
> +};
> +
> +struct axiom_target_report {
> +       u8 index;
> +       u8 present;
> +       u16 x;
> +       u16 y;
> +       s8 z;
> +};
> +
> +struct axiom_cmd_header {
> +       __le16 target_address;
> +       __le16 length;
> +} __packed;
> +
> +struct axiom_data {
> +       struct axiom_devinfo devinfo;
> +       struct device *dev;
> +       struct gpio_desc *reset_gpio;
> +       struct i2c_client *client;
> +       struct input_dev *input_dev;
> +       u32 max_report_len;
> +       char rx_buf[AXIOM_COMMS_MAX_USAGE_PAGES * AXIOM_COMMS_PAGE_SIZE];
> +       struct axiom_u41_target targets[AXIOM_U41_MAX_TARGETS];
> +       struct axiom_usage_entry usage_table[AXIOM_U31_MAX_USAGES];
> +       bool usage_table_populated;
> +       struct regulator *vdda;
> +       struct regulator *vddi;
> +};
> +
> +/*
> + * axiom devices are typically configured to report
> + * touches at a rate of 100Hz (10ms). For systems
> + * that require polling for reports.
> + * When reports are polled, it will be expected to
> + * occasionally observe the overflow bit being set
> + * in the reports. This indicates that reports are not
> + * being read fast enough.
> + */
> +#define POLL_INTERVAL_DEFAULT_MS 10
> +
> +/* Translate usage/page/offset triplet into physical address. */
> +static u16 axiom_usage_to_target_address(struct axiom_data *ts, char usage, char page,
> +                                        char offset)
> +{
> +       struct axiom_usage_entry *usage_table;
> +       struct axiom_devinfo *device_info;
> +       u32 i;
> +
> +       device_info = &ts->devinfo;
> +       usage_table = ts->usage_table;
> +
> +       /* At the moment the convention is that u31 is always at physical address 0x0 */
> +       if (!ts->usage_table_populated) {
> +               if (usage == AXIOM_DEVINFO_USAGE_ID)
> +                       return ((page << 8) + offset);
> +               else
> +                       return 0xffff;
> +       }
> +
> +       for (i = 0; i < ts->devinfo.num_usages; i++) {
> +               if (usage_table[i].id != usage)
> +                       continue;
> +
> +               if (page >= usage_table[i].num_pages) {
> +                       dev_err(ts->dev, "Invalid usage table! usage: %u, page: %u, offset: %u\n",
> +                               usage, page, offset);
> +                       return 0xffff;
> +               }
> +               break;
> +       }
> +
> +       return ((usage_table[i].start_page + page) << 8) + offset;
> +}
> +
> +static int axiom_i2c_read(struct i2c_client *client, u8 usage, u8 page, u8 *buf, u16 len)
> +{
> +       struct axiom_data *ts = i2c_get_clientdata(client);
> +       struct axiom_cmd_header cmd_header;
> +       u8 buffer[sizeof(cmd_header) + AXIOM_COMMS_PAGE_SIZE];
> +       struct i2c_msg msg;
> +       int error;
> +
> +       cmd_header.target_address = cpu_to_le16(axiom_usage_to_target_address(ts, usage, page, 0));
> +       cmd_header.length = cpu_to_le16(len | AXIOM_CMD_HEADER_READ_MASK);
> +
> +       memcpy(&buffer[0], &cmd_header, sizeof(cmd_header));
> +       memcpy(&buffer[sizeof(cmd_header)], buf, len);

You're copying a buffer that is meant to hold the response which makes 
no sense.
Please stick to the original implementation which transfers 2 messages :
- first is the header (you're telling the controller what you want to 
read) : this is a write and flags should be 0.
- second is the actual read message : flags should be I2C_M_RD

> +
> +       msg.addr = client->addr;
> +       msg.flags = 0;
> +       msg.len = len + sizeof(cmd_header);
> +       msg.buf = (u8 *)buffer;
> +
> +       error = i2c_transfer(client->adapter, &msg, 1);
> +       if (error != 1) {
You should transfer 2 messages (see above).
> +               dev_err(&client->dev,
> +                       "Failed reading usage %#x page %#x, error=%d\n",
> +                       usage, page, error);
> +               return error;
> +       }
> +
> +       usleep_range(100, 250);
The delay here is not enough as Touchnetix confirmed that we would need 
250 usecs for the controller's internal DMA to be ready after an i2c 
transfer.
> +
> +       return 0;
> +}
> +
> +/*
> + * One of the main purposes for reading the usage table is to identify
> + * which usages reside at which TA address.
> + * When performing subsequent reads or writes to AXIOM, the TA is used
> + * to specify which usage is being accessed.
> + * Consider the following discovery code which will build up the usage table.
> + */
> +static u32 axiom_populate_usage_table(struct axiom_data *ts)
> +{
> +       struct axiom_usage_entry *usage_table;
> +       u32 max_report_len = 0;
> +       char *rx_data = ts->rx_buf;
> +       u32 usage_id;
> +       int error;
> +
> +       usage_table = ts->usage_table;
> +
> +       /* Read the second page of usage u31 to get the usage table */
> +       error = axiom_i2c_read(ts->client, AXIOM_DEVINFO_USAGE_ID, 1, rx_data,
> +                              (AXIOM_U31_BYTES_PER_USAGE * ts->devinfo.num_usages));
> +       if (error)
> +               return error;
> +
> +       for (usage_id = 0; usage_id < ts->devinfo.num_usages; usage_id++) {
> +               u16 offset = (usage_id * AXIOM_U31_BYTES_PER_USAGE);
> +               u8 id = rx_data[offset + 0];
> +               u8 start_page = rx_data[offset + 1];
> +               u8 num_pages = rx_data[offset + 2];
> +               u32 max_offset = ((rx_data[offset + 3] & AXIOM_PAGE_OFFSET_MASK) + 1) * 2;
> +
> +               if (!num_pages)
> +                       usage_table[usage_id].is_report = true;
> +
> +               /* Store the entry into the usage table */
> +               usage_table[usage_id].id = id;
> +               usage_table[usage_id].start_page = start_page;
> +               usage_table[usage_id].num_pages = num_pages;
> +
> +               dev_dbg(ts->dev, "Usage u%02x Info: %*ph\n", id,
> +                       AXIOM_U31_BYTES_PER_USAGE, &rx_data[offset]);
> +
> +               /* Identify the max report length the module will receive */
> +               if (usage_table[usage_id].is_report && max_offset > max_report_len)
> +                       max_report_len = max_offset;
> +       }
> +
> +       ts->usage_table_populated = true;
> +
> +       return max_report_len;
> +}
> +
> +static int axiom_discover(struct axiom_data *ts)
> +{
> +       int error;
> +
> +       /*
> +        * Fetch the first page of usage u31 to get the
> +        * device information and the number of usages
> +        */
> +       error = axiom_i2c_read(ts->client, AXIOM_DEVINFO_USAGE_ID, 0, (char *)&ts->devinfo,
> +                              AXIOM_U31_PAGE0_LENGTH);
> +       if (error)
> +               return error;
> +
> +       dev_dbg(ts->dev, "  Boot Mode      : %s\n",
> +               FIELD_GET(AXIOM_U31_BOOTMODE_MASK, ts->devinfo.device_id) ? "BLP" : "TCP");
> +       dev_dbg(ts->dev, "  Device ID      : %04lx\n",
> +               FIELD_GET(AXIOM_U31_DEVID_MASK, ts->devinfo.device_id));
> +       dev_dbg(ts->dev, "  Firmware Rev   : %02x.%02x\n", ts->devinfo.fw_major,
> +               ts->devinfo.fw_minor);
> +       dev_dbg(ts->dev, "  Bootloader Rev : %02x.%02x\n", ts->devinfo.bootloader_fw_major,
> +               ts->devinfo.bootloader_fw_minor);
> +       dev_dbg(ts->dev, "  FW Extra Info  : %04x\n", ts->devinfo.fw_info_extra);
> +       dev_dbg(ts->dev, "  Silicon        : %04x\n", ts->devinfo.jedec_id);
> +       dev_dbg(ts->dev, "  Number usages        : %04x\n", ts->devinfo.num_usages);
> +
> +       ts->max_report_len = axiom_populate_usage_table(ts);
> +       if (!ts->max_report_len || !ts->devinfo.num_usages)
> +               return -EINVAL;
> +
> +       dev_dbg(ts->dev, "Max Report Length: %u\n", ts->max_report_len);
> +
> +       return 0;
> +}
> +
> +/*
> + * Support function to axiom_process_u41_report.
> + * Generates input-subsystem events for every target.
> + * After calling this function the caller shall issue
> + * a Sync to the input sub-system.
> + */
> +static bool axiom_process_u41_report_target(struct axiom_data *ts,
> +                                           struct axiom_target_report *target)
> +{
> +       struct input_dev *input_dev = ts->input_dev;
> +       struct axiom_u41_target *target_prev_state;
> +       enum axiom_target_state current_state;
> +       bool update = false;
> +       int slot;
> +
> +       /* Verify the target index */
> +       if (target->index >= AXIOM_U41_MAX_TARGETS) {
> +               dev_dbg(ts->dev, "Invalid target index! %u\n", target->index);
> +               return false;
> +       }
> +
> +       target_prev_state = &ts->targets[target->index];
> +
> +       current_state = AXIOM_TARGET_STATE_NOT_PRESENT;
> +
> +       if (target->present) {
> +               if (target->z >= 0)
> +                       current_state = AXIOM_TARGET_STATE_TOUCHING;
> +               else if (target->z > AXIOM_PROX_LEVEL && target->z < 0)
> +                       current_state = AXIOM_TARGET_STATE_HOVER;
> +               else if (target->z == AXIOM_PROX_LEVEL)
> +                       current_state = AXIOM_TARGET_STATE_PROX;
> +       }
> +
> +       if (target_prev_state->state == current_state &&
> +           target_prev_state->x == target->x &&
> +           target_prev_state->y == target->y &&
> +           target_prev_state->z == target->z) {
> +               return false;
> +       }
> +
> +       slot = target->index;
> +
> +       dev_dbg(ts->dev, "U41 Target T%u, slot:%u present:%u, x:%u, y:%u, z:%d\n",
> +               target->index, slot, target->present,
> +               target->x, target->y, target->z);
> +
> +       switch (current_state) {
> +       case AXIOM_TARGET_STATE_NOT_PRESENT:
> +       case AXIOM_TARGET_STATE_PROX:
> +               if (!target_prev_state->insert)
> +                       break;
> +               update = true;
> +               target_prev_state->insert = false;
> +               input_mt_slot(input_dev, slot);
> +
> +               if (!slot)
> +                       input_report_key(input_dev, BTN_TOUCH, 0);
> +
> +               input_mt_report_slot_inactive(input_dev);
> +               /*
> +                * make sure the previous coordinates are
> +                * all off screen when the finger comes back
> +                */
> +               target->x = 65535;
> +               target->y = 65535;
> +               target->z = AXIOM_PROX_LEVEL;
> +               break;
> +       case AXIOM_TARGET_STATE_HOVER:
> +       case AXIOM_TARGET_STATE_TOUCHING:
> +               target_prev_state->insert = true;
> +               update = true;
> +               input_mt_slot(input_dev, slot);
> +               input_report_abs(input_dev, ABS_MT_TRACKING_ID, slot);
> +               input_report_abs(input_dev, ABS_MT_POSITION_X, target->x);
> +               input_report_abs(input_dev, ABS_X, target->x);
> +               input_report_abs(input_dev, ABS_MT_POSITION_Y, target->y);
> +               input_report_abs(input_dev, ABS_Y, target->y);
> +
> +               if (current_state == AXIOM_TARGET_STATE_TOUCHING) {
> +                       input_report_abs(input_dev, ABS_MT_DISTANCE, 0);
> +                       input_report_abs(input_dev, ABS_DISTANCE, 0);
> +                       input_report_abs(input_dev, ABS_MT_PRESSURE, target->z);
> +                       input_report_abs(input_dev, ABS_PRESSURE, target->z);
> +               } else {
> +                       input_report_abs(input_dev, ABS_MT_DISTANCE, -target->z);
> +                       input_report_abs(input_dev, ABS_DISTANCE, -target->z);
> +                       input_report_abs(input_dev, ABS_MT_PRESSURE, 0);
> +                       input_report_abs(input_dev, ABS_PRESSURE, 0);
> +               }
> +
> +               if (!slot)
> +                       input_report_key(input_dev, BTN_TOUCH, (current_state ==
> +                                        AXIOM_TARGET_STATE_TOUCHING));
> +               break;
> +       default:
> +               break;
> +       }
> +
> +       target_prev_state->state = current_state;
> +       target_prev_state->x = target->x;
> +       target_prev_state->y = target->y;
> +       target_prev_state->z = target->z;
> +
> +       return update;
> +}
> +
> +/*
> + * U41 is the output report of the 2D CTS and contains the status of targets
> + * (including contacts and pre-contacts) along with their X,Y,Z values.
> + * When a target has been removed (no longer detected),
> + * the corresponding X,Y,Z values will be zeroed.
> + */
> +static bool axiom_process_u41_report(struct axiom_data *ts, char *rx_buf)
> +{
> +       struct axiom_target_report target;
> +       bool update_done = false;
> +       u16 target_status;
> +       u32 i;
> +
> +       target_status = ((rx_buf[1]) | (rx_buf[2] << 8));
> +
> +       for (i = 0; i < AXIOM_U41_MAX_TARGETS; i++) {
> +               char target_step = i * 4;
> +
> +               target.index = i;
> +               target.present = ((target_status & (1 << i)) != 0) ? 1 : 0;
> +               target.x = (rx_buf[(target_step + 3)] | (rx_buf[target_step + 4] << 8));
> +               target.y = (rx_buf[(target_step + 5)] | (rx_buf[target_step + 6] << 8));
> +               target.z = (s8)(rx_buf[i + 43]);
> +               update_done |= axiom_process_u41_report_target(ts, &target);
> +       }
> +
> +       return update_done;
> +}
> +
> +/*
> + * U46 report contains a low level measurement data generated by the CDS
> + * algorithms from the AUX channels. This information is useful when tuning
> + * multi-press to assess mechanical consistency in the unit's construction.
> + */
> +static void axiom_process_u46_report(struct axiom_data *ts, char *rx_buf)
> +{
> +       struct input_dev *input_dev = ts->input_dev;
> +       u32 event_value;
> +       u16 aux_value;
> +       u32 i = 0;
> +
> +       for (i = 0; i < AXIOM_U46_AUX_CHANNELS; i++) {
> +               char target_step = i * 2;
> +
> +               aux_value = ((rx_buf[target_step + 2] << 8) | (rx_buf[target_step + 1]))
> +                            & AXIOM_U46_AUX_MASK;
> +               event_value = (i << 16) | (aux_value);
> +               input_event(input_dev, EV_MSC, MSC_RAW, event_value);
> +       }
> +}
> +
> +/*
> + * Validates the crc and demultiplexes the axiom reports to the appropriate
> + * report handler
> + */
> +static int axiom_handle_events(struct axiom_data *ts)
> +{
> +       struct input_dev *input_dev = ts->input_dev;
> +       char *report_data = ts->rx_buf;
> +       char report_len;
> +       struct device *dev = ts->dev;
> +       u16 crc_report;
> +       u16 crc_calc;
> +       int error;
> +
> +       error = axiom_i2c_read(ts->client, AXIOM_REPORT_USAGE_ID, 0, &report_len,
> +                              sizeof(report_len));

I know that I told you it would be better to do the read report in 2 
phases, but we should have stick to Touchnetix recommendation that is to 
read the whole report even if it's padded with zeroes.
This is to avoid the 250 usecs delay after the read of the report length.

> +       if (error)
> +               return error;
> +
> +       report_len = (report_len & AXIOM_COMMS_REPORT_LEN_MASK) << 1;
> +       if (!report_len) {
> +               dev_err(dev, "Zero length report discarded\n");
> +               return -ENODATA;
> +       }
> +
> +       error = axiom_i2c_read(ts->client, AXIOM_REPORT_USAGE_ID, 0, report_data, report_len);
> +       if (error)
> +               return error;
> +
> +       /* Validate the report CRC */
> +       crc_report = (report_data[report_len - 1] << 8) | (report_data[report_len - 2]);
> +       /* Length is in 16 bit words and remove the size of the CRC16 itself */
> +       crc_calc = crc16(0, report_data, (report_len - 2));
> +
> +       if (crc_calc != crc_report) {
> +               dev_err(dev,
> +                       "CRC mismatch! Expected: %#x, Calculated CRC: %#x.\n",
> +                       crc_report, crc_calc);
> +               return -EINVAL;
> +       }
> +
> +       switch (report_data[1]) {
> +       case AXIOM_USAGE_2DCTS_REPORT_ID:
> +               if (axiom_process_u41_report(ts, &report_data[1])) {
> +                       input_mt_sync_frame(input_dev);
> +                       input_sync(input_dev);
> +               }
> +               break;
> +
> +       case AXIOM_USAGE_2AUX_REPORT_ID:
> +               /* This is an aux report (force) */
> +               axiom_process_u46_report(ts, &report_data[1]);
> +               input_mt_sync(input_dev);
> +               input_sync(input_dev);
> +               break;
> +
> +       case AXIOM_USAGE_2HB_REPORT_ID:
> +               /* This is a heartbeat report */
> +               break;
> +       default:
> +               return -EINVAL;
> +       }
> +
> +       return 0;
> +}
> +
> +static void axiom_i2c_poll(struct input_dev *input_dev)
> +{
> +       struct axiom_data *ts = input_get_drvdata(input_dev);
> +
> +       axiom_handle_events(ts);
> +}
> +
> +static irqreturn_t axiom_irq(int irq, void *dev_id)
> +{
> +       struct axiom_data *ts = dev_id;
> +
> +       axiom_handle_events(ts);
> +
> +       return IRQ_HANDLED;
> +}
> +
> +static void axiom_reset(struct gpio_desc *reset_gpio)
> +{
> +       gpiod_set_value_cansleep(reset_gpio, 1);
> +       usleep_range(1000, 2000);
> +       gpiod_set_value_cansleep(reset_gpio, 0);
> +       msleep(110);
> +}
> +
> +static int axiom_i2c_probe(struct i2c_client *client)
> +{
> +       struct device *dev = &client->dev;
> +       struct input_dev *input_dev;
> +       struct axiom_data *ts;
> +       u32 startup_delay_ms;
> +       u32 poll_interval;
> +       int target;
> +       int error;
> +
> +       ts = devm_kzalloc(dev, sizeof(*ts), GFP_KERNEL);
> +       if (!ts)
> +               return -ENOMEM;
> +
> +       ts->client = client;
> +       i2c_set_clientdata(client, ts);
> +       ts->dev = dev;
> +
> +       ts->reset_gpio = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH);
> +       if (IS_ERR(ts->reset_gpio))
> +               return dev_err_probe(dev, PTR_ERR(ts->reset_gpio), "failed to get reset GPIO\n");
> +
> +       if (ts->reset_gpio)
> +               axiom_reset(ts->reset_gpio);
> +
> +       ts->vddi = devm_regulator_get_optional(dev, "VDDI");
> +       if (!IS_ERR(ts->vddi)) {
> +               error = regulator_enable(ts->vddi);
> +               if (error)
> +                       return dev_err_probe(&client->dev, PTR_ERR(ts->vddi),
> +                                            "Failed to enable VDDI regulator\n");
> +       }
> +
> +       ts->vdda = devm_regulator_get_optional(dev, "VDDA");
> +       if (!IS_ERR(ts->vdda)) {
> +               error = regulator_enable(ts->vdda);
> +               if (error) {
> +                       dev_err(dev, "Failed to get VDDA regulator\n");
> +                       regulator_disable(ts->vddi);
> +                       return error;
> +               }
> +               if (!device_property_read_u32(dev, "startup-time-ms", &startup_delay_ms))
> +                       msleep(startup_delay_ms);
> +       }
> +
> +       error = axiom_discover(ts);
> +       if (error)
> +               return dev_err_probe(dev, error, "Failed touchscreen discover\n");
> +
> +       input_dev = devm_input_allocate_device(ts->dev);
> +       if (!input_dev)
> +               return -ENOMEM;
> +
> +       input_dev->name = "TouchNetix axiom Touchscreen";
> +       input_dev->phys = "input/axiom_ts";
> +
> +       /* Single Touch */
> +       input_set_abs_params(input_dev, ABS_X, 0, 65535, 0, 0);
> +       input_set_abs_params(input_dev, ABS_Y, 0, 65535, 0, 0);
> +
> +       /* Multi Touch */
> +       /* Min, Max, Fuzz (expected noise in px, try 4?) and Flat */
> +       input_set_abs_params(input_dev, ABS_MT_POSITION_X, 0, 65535, 0, 0);
> +       /* Min, Max, Fuzz (expected noise in px, try 4?) and Flat */
> +       input_set_abs_params(input_dev, ABS_MT_POSITION_Y, 0, 65535, 0, 0);
> +       input_set_abs_params(input_dev, ABS_MT_TOOL_TYPE, 0, MT_TOOL_MAX, 0, 0);
> +       input_set_abs_params(input_dev, ABS_MT_DISTANCE, 0, 127, 0, 0);
> +       input_set_abs_params(input_dev, ABS_MT_PRESSURE, 0, 127, 0, 0);
> +
> +       input_set_capability(input_dev, EV_KEY, BTN_TOUCH);
> +
> +       /* Registers the axiom device as a touchscreen instead of a mouse pointer */
> +       error = input_mt_init_slots(input_dev, AXIOM_U41_MAX_TARGETS, INPUT_MT_DIRECT);
> +       if (error)
> +               return error;
> +
> +       /* Enables the raw data for up to 4 force channels to be sent to the input subsystem */
> +       set_bit(EV_REL, input_dev->evbit);
> +       set_bit(EV_MSC, input_dev->evbit);
> +       /* Declare that we support "RAW" Miscellaneous events */
> +       set_bit(MSC_RAW, input_dev->mscbit);
> +
> +       ts->input_dev = input_dev;
> +       input_set_drvdata(ts->input_dev, ts);
> +
> +       /* Ensure that all reports are initialised to not be present. */
> +       for (target = 0; target < AXIOM_U41_MAX_TARGETS; target++)
> +               ts->targets[target].state = AXIOM_TARGET_STATE_NOT_PRESENT;
> +
> +       error = input_register_device(input_dev);
> +       if (error)
> +               return dev_err_probe(ts->dev, error,
> +                                    "Could not register with Input Sub-system.\n");
> +
> +       error = devm_request_threaded_irq(dev, client->irq, NULL,
> +                                         axiom_irq, IRQF_ONESHOT, dev_name(dev), ts);
> +       if (error < 0) {
> +               dev_warn(dev, "Request irq failed, falling back to polling mode");
> +
> +               error = input_setup_polling(input_dev, axiom_i2c_poll);
> +               if (error)
> +                       return dev_err_probe(ts->dev, error, "Unable to set up polling mode\n");
> +
> +               if (!device_property_read_u32(ts->dev, "poll-interval", &poll_interval))
> +                       input_set_poll_interval(input_dev, poll_interval);
> +               else
> +                       input_set_poll_interval(input_dev, POLL_INTERVAL_DEFAULT_MS);
> +       }
> +
> +       return 0;
> +}
> +
> +static const struct i2c_device_id axiom_i2c_id_table[] = {
> +       { "ax54a" },
> +       {},
> +};
> +MODULE_DEVICE_TABLE(i2c, axiom_i2c_id_table);
> +
> +static const struct of_device_id axiom_i2c_of_match[] = {
> +       { .compatible = "touchnetix,ax54a", },
> +       { }
> +};
> +MODULE_DEVICE_TABLE(of, axiom_i2c_of_match);
> +
> +static struct i2c_driver axiom_i2c_driver = {
> +       .driver = {
> +                  .name = "axiom",
> +                  .of_match_table = axiom_i2c_of_match,
> +       },
> +       .id_table = axiom_i2c_id_table,
> +       .probe = axiom_i2c_probe,
> +};
> +module_i2c_driver(axiom_i2c_driver);
> +MODULE_AUTHOR("Bart Prescott <bartp@baasheep.co.uk>");
> +MODULE_AUTHOR("Pedro Torruella <pedro.torruella@touchnetix.com>");
> +MODULE_AUTHOR("Mark Satterthwaite <mark.satterthwaite@touchnetix.com>");
> +MODULE_AUTHOR("Hannah Rossiter <hannah.rossiter@touchnetix.com>");
> +MODULE_AUTHOR("Kamel Bouhara <kamel.bouhara@bootlin.com>");
> +MODULE_DESCRIPTION("TouchNetix axiom touchscreen I2C bus driver");
> +MODULE_LICENSE("GPL");
> --
> 2.25.1
>
Kamel BOUHARA Dec. 4, 2023, 4:16 p.m. UTC | #2
Le Mon, Dec 04, 2023 at 03:09:58PM +0000, POPESCU Catalin a écrit :
> On 04.12.23 15:05, Kamel Bouhara wrote:
> > This email is not from Hexagon’s Office 365 instance. Please be careful while clicking links, opening attachments, or replying to this email.
> >
> >
> > Add a new driver for the TouchNetix's axiom family of
> > touchscreen controllers. This driver only supports i2c
> > and can be later adapted for SPI and USB support.
> >
> > Signed-off-by: Kamel Bouhara <kamel.bouhara@bootlin.com>
> > ---
> >   MAINTAINERS                                  |   1 +
> >   drivers/input/touchscreen/Kconfig            |  12 +
> >   drivers/input/touchscreen/Makefile           |   1 +
> >   drivers/input/touchscreen/touchnetix_axiom.c | 675 +++++++++++++++++++
> >   4 files changed, 689 insertions(+)
> >   create mode 100644 drivers/input/touchscreen/touchnetix_axiom.c
> >
> > diff --git a/MAINTAINERS b/MAINTAINERS
> > index 4752d8436dbb..337ddac6c74b 100644
> > --- a/MAINTAINERS
> > +++ b/MAINTAINERS
> > @@ -21436,6 +21436,7 @@ M:      Kamel Bouhara <kamel.bouhara@bootlin.com>
> >   L:     linux-input@vger.kernel.org
> >   S:     Maintained
> >   F:     Documentation/devicetree/bindings/input/touchscreen/touchnetix,ax54a.yaml
> > +F:     drivers/input/touchscreen/touchnetix_axiom.c
> >
> >   THUNDERBOLT DMA TRAFFIC TEST DRIVER
> >   M:     Isaac Hazan <isaac.hazan@intel.com>
> > diff --git a/drivers/input/touchscreen/Kconfig b/drivers/input/touchscreen/Kconfig
> > index e3e2324547b9..f36bee8d8696 100644
> > --- a/drivers/input/touchscreen/Kconfig
> > +++ b/drivers/input/touchscreen/Kconfig
> > @@ -803,6 +803,18 @@ config TOUCHSCREEN_MIGOR
> >            To compile this driver as a module, choose M here: the
> >            module will be called migor_ts.
> >
> > +config TOUCHSCREEN_TOUCHNETIX_AXIOM
> > +       tristate "TouchNetix AXIOM based touchscreen controllers"
> > +       depends on I2C
> > +       help
> > +         Say Y here if you have a axiom touchscreen connected to
> > +         your system.
> > +
> > +         If unsure, say N.
> > +
> > +         To compile this driver as a module, choose M here: the
> > +         module will be called axiom.
> > +
> >   config TOUCHSCREEN_TOUCHRIGHT
> >          tristate "Touchright serial touchscreen"
> >          select SERIO
> > diff --git a/drivers/input/touchscreen/Makefile b/drivers/input/touchscreen/Makefile
> > index 62bd24f3ac8e..8e32a2df5e18 100644
> > --- a/drivers/input/touchscreen/Makefile
> > +++ b/drivers/input/touchscreen/Makefile
> > @@ -88,6 +88,7 @@ obj-$(CONFIG_TOUCHSCREEN_SUR40)               += sur40.o
> >   obj-$(CONFIG_TOUCHSCREEN_SURFACE3_SPI) += surface3_spi.o
> >   obj-$(CONFIG_TOUCHSCREEN_TI_AM335X_TSC)        += ti_am335x_tsc.o
> >   obj-$(CONFIG_TOUCHSCREEN_TOUCHIT213)   += touchit213.o
> > +obj-$(CONFIG_TOUCHSCREEN_TOUCHNETIX_AXIOM)     += touchnetix_axiom.o
> >   obj-$(CONFIG_TOUCHSCREEN_TOUCHRIGHT)   += touchright.o
> >   obj-$(CONFIG_TOUCHSCREEN_TOUCHWIN)     += touchwin.o
> >   obj-$(CONFIG_TOUCHSCREEN_TS4800)       += ts4800-ts.o
> > diff --git a/drivers/input/touchscreen/touchnetix_axiom.c b/drivers/input/touchscreen/touchnetix_axiom.c
> > new file mode 100644
> > index 000000000000..9783e89f9e3a
> > --- /dev/null
> > +++ b/drivers/input/touchscreen/touchnetix_axiom.c
> > @@ -0,0 +1,675 @@
> > +// SPDX-License-Identifier: GPL-2.0-only
> > +/*
> > + * TouchNetix axiom Touchscreen Driver
> > + *
> > + * Copyright (C) 2020-2023 TouchNetix Ltd.
> > + *
> > + * Author(s): Bart Prescott <bartp@baasheep.co.uk>
> > + *            Pedro Torruella <pedro.torruella@touchnetix.com>
> > + *            Mark Satterthwaite <mark.satterthwaite@touchnetix.com>
> > + *            Hannah Rossiter <hannah.rossiter@touchnetix.com>
> > + *            Kamel Bouhara <kamel.bouhara@bootlin.com>
> > + *
> > + */
> > +#include <linux/bitfield.h>
> > +#include <linux/crc16.h>
> > +#include <linux/delay.h>
> > +#include <linux/device.h>
> > +#include <linux/gpio/consumer.h>
> > +#include <linux/i2c.h>
> > +#include <linux/input.h>
> > +#include <linux/input/mt.h>
> > +#include <linux/interrupt.h>
> > +#include <linux/kernel.h>
> > +#include <linux/module.h>
> > +#include <linux/of.h>
> > +
> > +#define AXIOM_PROX_LEVEL               -128
> > +/*
> > + * Register group u31 has 2 pages for usage table entries.
> > + */
> > +#define AXIOM_U31_MAX_USAGES           ((2 * AXIOM_COMMS_PAGE_SIZE) / AXIOM_U31_BYTES_PER_USAGE)
> > +#define AXIOM_U31_BYTES_PER_USAGE      6
> > +#define AXIOM_U31_PAGE0_LENGTH         0x0C
> > +#define AXIOM_U31_BOOTMODE_MASK                BIT(7)
> > +#define AXIOM_U31_DEVID_MASK           GENMASK(14, 0)
> > +
> > +#define AXIOM_CMD_HEADER_READ_MASK     BIT(15)
> > +#define AXIOM_U41_MAX_TARGETS          10
> > +
> > +#define AXIOM_U46_AUX_CHANNELS         4
> > +#define AXIOM_U46_AUX_MASK             GENMASK(11, 0)
> > +
> > +#define AXIOM_COMMS_MAX_USAGE_PAGES    3
> > +#define AXIOM_COMMS_PAGE_SIZE          256
> > +#define AXIOM_COMMS_REPORT_LEN_MASK    GENMASK(6, 0)
> > +
> > +#define AXIOM_REPORT_USAGE_ID          0x34
> > +#define AXIOM_DEVINFO_USAGE_ID         0x31
> > +#define AXIOM_USAGE_2HB_REPORT_ID      0x01
> > +#define AXIOM_USAGE_2AUX_REPORT_ID     0x46
> > +#define AXIOM_USAGE_2DCTS_REPORT_ID    0x41
> > +
> > +#define AXIOM_PAGE_OFFSET_MASK         GENMASK(6, 0)
> > +
> > +struct axiom_devinfo {
> > +       u16 device_id;
> > +       u8 fw_minor;
> > +       u8 fw_major;
> > +       u8 fw_info_extra;
> > +       u8 tcp_revision;
> > +       u8 bootloader_fw_minor;
> > +       u8 bootloader_fw_major;
> > +       u16 jedec_id;
> > +       u8 num_usages;
> > +} __packed;
> > +
> > +/*
> > + * Describes parameters of a specific usage, essentially a single element of
> > + * the "Usage Table"
> > + */
> > +struct axiom_usage_entry {
> > +       u8 id;
> > +       u8 is_report;
> > +       u8 start_page;
> > +       u8 num_pages;
> > +};
> > +
> > +/*
> > + * Represents state of a touch or target when detected prior a touch (eg.
> > + * hover or proximity events).
> > + */
> > +enum axiom_target_state {
> > +       AXIOM_TARGET_STATE_NOT_PRESENT = 0,
> > +       AXIOM_TARGET_STATE_PROX = 1,
> > +       AXIOM_TARGET_STATE_HOVER = 2,
> > +       AXIOM_TARGET_STATE_TOUCHING = 3,
> > +};
> > +
> > +struct axiom_u41_target {
> > +       enum axiom_target_state state;
> > +       u16 x;
> > +       u16 y;
> > +       s8 z;
> > +       bool insert;
> > +       bool touch;
> > +};
> > +
> > +struct axiom_target_report {
> > +       u8 index;
> > +       u8 present;
> > +       u16 x;
> > +       u16 y;
> > +       s8 z;
> > +};
> > +
> > +struct axiom_cmd_header {
> > +       __le16 target_address;
> > +       __le16 length;
> > +} __packed;
> > +
> > +struct axiom_data {
> > +       struct axiom_devinfo devinfo;
> > +       struct device *dev;
> > +       struct gpio_desc *reset_gpio;
> > +       struct i2c_client *client;
> > +       struct input_dev *input_dev;
> > +       u32 max_report_len;
> > +       char rx_buf[AXIOM_COMMS_MAX_USAGE_PAGES * AXIOM_COMMS_PAGE_SIZE];
> > +       struct axiom_u41_target targets[AXIOM_U41_MAX_TARGETS];
> > +       struct axiom_usage_entry usage_table[AXIOM_U31_MAX_USAGES];
> > +       bool usage_table_populated;
> > +       struct regulator *vdda;
> > +       struct regulator *vddi;
> > +};
> > +
> > +/*
> > + * axiom devices are typically configured to report
> > + * touches at a rate of 100Hz (10ms). For systems
> > + * that require polling for reports.
> > + * When reports are polled, it will be expected to
> > + * occasionally observe the overflow bit being set
> > + * in the reports. This indicates that reports are not
> > + * being read fast enough.
> > + */
> > +#define POLL_INTERVAL_DEFAULT_MS 10
> > +
> > +/* Translate usage/page/offset triplet into physical address. */
> > +static u16 axiom_usage_to_target_address(struct axiom_data *ts, char usage, char page,
> > +                                        char offset)
> > +{
> > +       struct axiom_usage_entry *usage_table;
> > +       struct axiom_devinfo *device_info;
> > +       u32 i;
> > +
> > +       device_info = &ts->devinfo;
> > +       usage_table = ts->usage_table;
> > +
> > +       /* At the moment the convention is that u31 is always at physical address 0x0 */
> > +       if (!ts->usage_table_populated) {
> > +               if (usage == AXIOM_DEVINFO_USAGE_ID)
> > +                       return ((page << 8) + offset);
> > +               else
> > +                       return 0xffff;
> > +       }
> > +
> > +       for (i = 0; i < ts->devinfo.num_usages; i++) {
> > +               if (usage_table[i].id != usage)
> > +                       continue;
> > +
> > +               if (page >= usage_table[i].num_pages) {
> > +                       dev_err(ts->dev, "Invalid usage table! usage: %u, page: %u, offset: %u\n",
> > +                               usage, page, offset);
> > +                       return 0xffff;
> > +               }
> > +               break;
> > +       }
> > +
> > +       return ((usage_table[i].start_page + page) << 8) + offset;
> > +}
> > +
> > +static int axiom_i2c_read(struct i2c_client *client, u8 usage, u8 page, u8 *buf, u16 len)
> > +{
> > +       struct axiom_data *ts = i2c_get_clientdata(client);
> > +       struct axiom_cmd_header cmd_header;
> > +       u8 buffer[sizeof(cmd_header) + AXIOM_COMMS_PAGE_SIZE];
> > +       struct i2c_msg msg;
> > +       int error;
> > +
> > +       cmd_header.target_address = cpu_to_le16(axiom_usage_to_target_address(ts, usage, page, 0));
> > +       cmd_header.length = cpu_to_le16(len | AXIOM_CMD_HEADER_READ_MASK);
> > +
> > +       memcpy(&buffer[0], &cmd_header, sizeof(cmd_header));
> > +       memcpy(&buffer[sizeof(cmd_header)], buf, len);
>
> You're copying a buffer that is meant to hold the response which makes
> no sense.
> Please stick to the original implementation which transfers 2 messages :
> - first is the header (you're telling the controller what you want to
> read) : this is a write and flags should be 0.
> - second is the actual read message : flags should be I2C_M_RD

This was not supposed to be applied on read but rather axiom_i2c_write().

Fixed for v5, thanks.

>
> > +
> > +       msg.addr = client->addr;
> > +       msg.flags = 0;
> > +       msg.len = len + sizeof(cmd_header);
> > +       msg.buf = (u8 *)buffer;
> > +
> > +       error = i2c_transfer(client->adapter, &msg, 1);
> > +       if (error != 1) {
> You should transfer 2 messages (see above).
> > +               dev_err(&client->dev,
> > +                       "Failed reading usage %#x page %#x, error=%d\n",
> > +                       usage, page, error);
> > +               return error;
> > +       }
> > +
> > +       usleep_range(100, 250);
> The delay here is not enough as Touchnetix confirmed that we would need
> 250 usecs for the controller's internal DMA to be ready after an i2c
> transfer.

Ok that wasn't clear if it was after 2 consecutives reads but now it is.

Maybe Mark can confirm again ?

> > +
> > +       return 0;
> > +}
> > +
> > +/*
> > + * One of the main purposes for reading the usage table is to identify
> > + * which usages reside at which TA address.
> > + * When performing subsequent reads or writes to AXIOM, the TA is used
> > + * to specify which usage is being accessed.
> > + * Consider the following discovery code which will build up the usage table.
> > + */
> > +static u32 axiom_populate_usage_table(struct axiom_data *ts)
> > +{
> > +       struct axiom_usage_entry *usage_table;
> > +       u32 max_report_len = 0;
> > +       char *rx_data = ts->rx_buf;
> > +       u32 usage_id;
> > +       int error;
> > +
> > +       usage_table = ts->usage_table;
> > +
> > +       /* Read the second page of usage u31 to get the usage table */
> > +       error = axiom_i2c_read(ts->client, AXIOM_DEVINFO_USAGE_ID, 1, rx_data,
> > +                              (AXIOM_U31_BYTES_PER_USAGE * ts->devinfo.num_usages));
> > +       if (error)
> > +               return error;
> > +
> > +       for (usage_id = 0; usage_id < ts->devinfo.num_usages; usage_id++) {
> > +               u16 offset = (usage_id * AXIOM_U31_BYTES_PER_USAGE);
> > +               u8 id = rx_data[offset + 0];
> > +               u8 start_page = rx_data[offset + 1];
> > +               u8 num_pages = rx_data[offset + 2];
> > +               u32 max_offset = ((rx_data[offset + 3] & AXIOM_PAGE_OFFSET_MASK) + 1) * 2;
> > +
> > +               if (!num_pages)
> > +                       usage_table[usage_id].is_report = true;
> > +
> > +               /* Store the entry into the usage table */
> > +               usage_table[usage_id].id = id;
> > +               usage_table[usage_id].start_page = start_page;
> > +               usage_table[usage_id].num_pages = num_pages;
> > +
> > +               dev_dbg(ts->dev, "Usage u%02x Info: %*ph\n", id,
> > +                       AXIOM_U31_BYTES_PER_USAGE, &rx_data[offset]);
> > +
> > +               /* Identify the max report length the module will receive */
> > +               if (usage_table[usage_id].is_report && max_offset > max_report_len)
> > +                       max_report_len = max_offset;
> > +       }
> > +
> > +       ts->usage_table_populated = true;
> > +
> > +       return max_report_len;
> > +}
> > +
> > +static int axiom_discover(struct axiom_data *ts)
> > +{
> > +       int error;
> > +
> > +       /*
> > +        * Fetch the first page of usage u31 to get the
> > +        * device information and the number of usages
> > +        */
> > +       error = axiom_i2c_read(ts->client, AXIOM_DEVINFO_USAGE_ID, 0, (char *)&ts->devinfo,
> > +                              AXIOM_U31_PAGE0_LENGTH);
> > +       if (error)
> > +               return error;
> > +
> > +       dev_dbg(ts->dev, "  Boot Mode      : %s\n",
> > +               FIELD_GET(AXIOM_U31_BOOTMODE_MASK, ts->devinfo.device_id) ? "BLP" : "TCP");
> > +       dev_dbg(ts->dev, "  Device ID      : %04lx\n",
> > +               FIELD_GET(AXIOM_U31_DEVID_MASK, ts->devinfo.device_id));
> > +       dev_dbg(ts->dev, "  Firmware Rev   : %02x.%02x\n", ts->devinfo.fw_major,
> > +               ts->devinfo.fw_minor);
> > +       dev_dbg(ts->dev, "  Bootloader Rev : %02x.%02x\n", ts->devinfo.bootloader_fw_major,
> > +               ts->devinfo.bootloader_fw_minor);
> > +       dev_dbg(ts->dev, "  FW Extra Info  : %04x\n", ts->devinfo.fw_info_extra);
> > +       dev_dbg(ts->dev, "  Silicon        : %04x\n", ts->devinfo.jedec_id);
> > +       dev_dbg(ts->dev, "  Number usages        : %04x\n", ts->devinfo.num_usages);
> > +
> > +       ts->max_report_len = axiom_populate_usage_table(ts);
> > +       if (!ts->max_report_len || !ts->devinfo.num_usages)
> > +               return -EINVAL;
> > +
> > +       dev_dbg(ts->dev, "Max Report Length: %u\n", ts->max_report_len);
> > +
> > +       return 0;
> > +}
> > +
> > +/*
> > + * Support function to axiom_process_u41_report.
> > + * Generates input-subsystem events for every target.
> > + * After calling this function the caller shall issue
> > + * a Sync to the input sub-system.
> > + */
> > +static bool axiom_process_u41_report_target(struct axiom_data *ts,
> > +                                           struct axiom_target_report *target)
> > +{
> > +       struct input_dev *input_dev = ts->input_dev;
> > +       struct axiom_u41_target *target_prev_state;
> > +       enum axiom_target_state current_state;
> > +       bool update = false;
> > +       int slot;
> > +
> > +       /* Verify the target index */
> > +       if (target->index >= AXIOM_U41_MAX_TARGETS) {
> > +               dev_dbg(ts->dev, "Invalid target index! %u\n", target->index);
> > +               return false;
> > +       }
> > +
> > +       target_prev_state = &ts->targets[target->index];
> > +
> > +       current_state = AXIOM_TARGET_STATE_NOT_PRESENT;
> > +
> > +       if (target->present) {
> > +               if (target->z >= 0)
> > +                       current_state = AXIOM_TARGET_STATE_TOUCHING;
> > +               else if (target->z > AXIOM_PROX_LEVEL && target->z < 0)
> > +                       current_state = AXIOM_TARGET_STATE_HOVER;
> > +               else if (target->z == AXIOM_PROX_LEVEL)
> > +                       current_state = AXIOM_TARGET_STATE_PROX;
> > +       }
> > +
> > +       if (target_prev_state->state == current_state &&
> > +           target_prev_state->x == target->x &&
> > +           target_prev_state->y == target->y &&
> > +           target_prev_state->z == target->z) {
> > +               return false;
> > +       }
> > +
> > +       slot = target->index;
> > +
> > +       dev_dbg(ts->dev, "U41 Target T%u, slot:%u present:%u, x:%u, y:%u, z:%d\n",
> > +               target->index, slot, target->present,
> > +               target->x, target->y, target->z);
> > +
> > +       switch (current_state) {
> > +       case AXIOM_TARGET_STATE_NOT_PRESENT:
> > +       case AXIOM_TARGET_STATE_PROX:
> > +               if (!target_prev_state->insert)
> > +                       break;
> > +               update = true;
> > +               target_prev_state->insert = false;
> > +               input_mt_slot(input_dev, slot);
> > +
> > +               if (!slot)
> > +                       input_report_key(input_dev, BTN_TOUCH, 0);
> > +
> > +               input_mt_report_slot_inactive(input_dev);
> > +               /*
> > +                * make sure the previous coordinates are
> > +                * all off screen when the finger comes back
> > +                */
> > +               target->x = 65535;
> > +               target->y = 65535;
> > +               target->z = AXIOM_PROX_LEVEL;
> > +               break;
> > +       case AXIOM_TARGET_STATE_HOVER:
> > +       case AXIOM_TARGET_STATE_TOUCHING:
> > +               target_prev_state->insert = true;
> > +               update = true;
> > +               input_mt_slot(input_dev, slot);
> > +               input_report_abs(input_dev, ABS_MT_TRACKING_ID, slot);
> > +               input_report_abs(input_dev, ABS_MT_POSITION_X, target->x);
> > +               input_report_abs(input_dev, ABS_X, target->x);
> > +               input_report_abs(input_dev, ABS_MT_POSITION_Y, target->y);
> > +               input_report_abs(input_dev, ABS_Y, target->y);
> > +
> > +               if (current_state == AXIOM_TARGET_STATE_TOUCHING) {
> > +                       input_report_abs(input_dev, ABS_MT_DISTANCE, 0);
> > +                       input_report_abs(input_dev, ABS_DISTANCE, 0);
> > +                       input_report_abs(input_dev, ABS_MT_PRESSURE, target->z);
> > +                       input_report_abs(input_dev, ABS_PRESSURE, target->z);
> > +               } else {
> > +                       input_report_abs(input_dev, ABS_MT_DISTANCE, -target->z);
> > +                       input_report_abs(input_dev, ABS_DISTANCE, -target->z);
> > +                       input_report_abs(input_dev, ABS_MT_PRESSURE, 0);
> > +                       input_report_abs(input_dev, ABS_PRESSURE, 0);
> > +               }
> > +
> > +               if (!slot)
> > +                       input_report_key(input_dev, BTN_TOUCH, (current_state ==
> > +                                        AXIOM_TARGET_STATE_TOUCHING));
> > +               break;
> > +       default:
> > +               break;
> > +       }
> > +
> > +       target_prev_state->state = current_state;
> > +       target_prev_state->x = target->x;
> > +       target_prev_state->y = target->y;
> > +       target_prev_state->z = target->z;
> > +
> > +       return update;
> > +}
> > +
> > +/*
> > + * U41 is the output report of the 2D CTS and contains the status of targets
> > + * (including contacts and pre-contacts) along with their X,Y,Z values.
> > + * When a target has been removed (no longer detected),
> > + * the corresponding X,Y,Z values will be zeroed.
> > + */
> > +static bool axiom_process_u41_report(struct axiom_data *ts, char *rx_buf)
> > +{
> > +       struct axiom_target_report target;
> > +       bool update_done = false;
> > +       u16 target_status;
> > +       u32 i;
> > +
> > +       target_status = ((rx_buf[1]) | (rx_buf[2] << 8));
> > +
> > +       for (i = 0; i < AXIOM_U41_MAX_TARGETS; i++) {
> > +               char target_step = i * 4;
> > +
> > +               target.index = i;
> > +               target.present = ((target_status & (1 << i)) != 0) ? 1 : 0;
> > +               target.x = (rx_buf[(target_step + 3)] | (rx_buf[target_step + 4] << 8));
> > +               target.y = (rx_buf[(target_step + 5)] | (rx_buf[target_step + 6] << 8));
> > +               target.z = (s8)(rx_buf[i + 43]);
> > +               update_done |= axiom_process_u41_report_target(ts, &target);
> > +       }
> > +
> > +       return update_done;
> > +}
> > +
> > +/*
> > + * U46 report contains a low level measurement data generated by the CDS
> > + * algorithms from the AUX channels. This information is useful when tuning
> > + * multi-press to assess mechanical consistency in the unit's construction.
> > + */
> > +static void axiom_process_u46_report(struct axiom_data *ts, char *rx_buf)
> > +{
> > +       struct input_dev *input_dev = ts->input_dev;
> > +       u32 event_value;
> > +       u16 aux_value;
> > +       u32 i = 0;
> > +
> > +       for (i = 0; i < AXIOM_U46_AUX_CHANNELS; i++) {
> > +               char target_step = i * 2;
> > +
> > +               aux_value = ((rx_buf[target_step + 2] << 8) | (rx_buf[target_step + 1]))
> > +                            & AXIOM_U46_AUX_MASK;
> > +               event_value = (i << 16) | (aux_value);
> > +               input_event(input_dev, EV_MSC, MSC_RAW, event_value);
> > +       }
> > +}
> > +
> > +/*
> > + * Validates the crc and demultiplexes the axiom reports to the appropriate
> > + * report handler
> > + */
> > +static int axiom_handle_events(struct axiom_data *ts)
> > +{
> > +       struct input_dev *input_dev = ts->input_dev;
> > +       char *report_data = ts->rx_buf;
> > +       char report_len;
> > +       struct device *dev = ts->dev;
> > +       u16 crc_report;
> > +       u16 crc_calc;
> > +       int error;
> > +
> > +       error = axiom_i2c_read(ts->client, AXIOM_REPORT_USAGE_ID, 0, &report_len,
> > +                              sizeof(report_len));
>
> I know that I told you it would be better to do the read report in 2
> phases, but we should have stick to Touchnetix recommendation that is to
> read the whole report even if it's padded with zeroes.
> This is to avoid the 250 usecs delay after the read of the report length.
>

Ack, thanks.

> > +       if (error)
> > +               return error;
> > +
> > +       report_len = (report_len & AXIOM_COMMS_REPORT_LEN_MASK) << 1;
> > +       if (!report_len) {
> > +               dev_err(dev, "Zero length report discarded\n");
> > +               return -ENODATA;
> > +       }
> > +
> > +       error = axiom_i2c_read(ts->client, AXIOM_REPORT_USAGE_ID, 0, report_data, report_len);
> > +       if (error)
> > +               return error;
> > +
> > +       /* Validate the report CRC */
> > +       crc_report = (report_data[report_len - 1] << 8) | (report_data[report_len - 2]);
> > +       /* Length is in 16 bit words and remove the size of the CRC16 itself */
> > +       crc_calc = crc16(0, report_data, (report_len - 2));
> > +
> > +       if (crc_calc != crc_report) {
> > +               dev_err(dev,
> > +                       "CRC mismatch! Expected: %#x, Calculated CRC: %#x.\n",
> > +                       crc_report, crc_calc);
> > +               return -EINVAL;
> > +       }
> > +
> > +       switch (report_data[1]) {
> > +       case AXIOM_USAGE_2DCTS_REPORT_ID:
> > +               if (axiom_process_u41_report(ts, &report_data[1])) {
> > +                       input_mt_sync_frame(input_dev);
> > +                       input_sync(input_dev);
> > +               }
> > +               break;
> > +
> > +       case AXIOM_USAGE_2AUX_REPORT_ID:
> > +               /* This is an aux report (force) */
> > +               axiom_process_u46_report(ts, &report_data[1]);
> > +               input_mt_sync(input_dev);
> > +               input_sync(input_dev);
> > +               break;
> > +
> > +       case AXIOM_USAGE_2HB_REPORT_ID:
> > +               /* This is a heartbeat report */
> > +               break;
> > +       default:
> > +               return -EINVAL;
> > +       }
> > +
> > +       return 0;
> > +}
> > +
> > +static void axiom_i2c_poll(struct input_dev *input_dev)
> > +{
> > +       struct axiom_data *ts = input_get_drvdata(input_dev);
> > +
> > +       axiom_handle_events(ts);
> > +}
> > +
> > +static irqreturn_t axiom_irq(int irq, void *dev_id)
> > +{
> > +       struct axiom_data *ts = dev_id;
> > +
> > +       axiom_handle_events(ts);
> > +
> > +       return IRQ_HANDLED;
> > +}
> > +
> > +static void axiom_reset(struct gpio_desc *reset_gpio)
> > +{
> > +       gpiod_set_value_cansleep(reset_gpio, 1);
> > +       usleep_range(1000, 2000);
> > +       gpiod_set_value_cansleep(reset_gpio, 0);
> > +       msleep(110);
> > +}
> > +
> > +static int axiom_i2c_probe(struct i2c_client *client)
> > +{
> > +       struct device *dev = &client->dev;
> > +       struct input_dev *input_dev;
> > +       struct axiom_data *ts;
> > +       u32 startup_delay_ms;
> > +       u32 poll_interval;
> > +       int target;
> > +       int error;
> > +
> > +       ts = devm_kzalloc(dev, sizeof(*ts), GFP_KERNEL);
> > +       if (!ts)
> > +               return -ENOMEM;
> > +
> > +       ts->client = client;
> > +       i2c_set_clientdata(client, ts);
> > +       ts->dev = dev;
> > +
> > +       ts->reset_gpio = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH);
> > +       if (IS_ERR(ts->reset_gpio))
> > +               return dev_err_probe(dev, PTR_ERR(ts->reset_gpio), "failed to get reset GPIO\n");
> > +
> > +       if (ts->reset_gpio)
> > +               axiom_reset(ts->reset_gpio);
> > +
> > +       ts->vddi = devm_regulator_get_optional(dev, "VDDI");
> > +       if (!IS_ERR(ts->vddi)) {
> > +               error = regulator_enable(ts->vddi);
> > +               if (error)
> > +                       return dev_err_probe(&client->dev, PTR_ERR(ts->vddi),
> > +                                            "Failed to enable VDDI regulator\n");
> > +       }
> > +
> > +       ts->vdda = devm_regulator_get_optional(dev, "VDDA");
> > +       if (!IS_ERR(ts->vdda)) {
> > +               error = regulator_enable(ts->vdda);
> > +               if (error) {
> > +                       dev_err(dev, "Failed to get VDDA regulator\n");
> > +                       regulator_disable(ts->vddi);
> > +                       return error;
> > +               }
> > +               if (!device_property_read_u32(dev, "startup-time-ms", &startup_delay_ms))
> > +                       msleep(startup_delay_ms);
> > +       }
> > +
> > +       error = axiom_discover(ts);
> > +       if (error)
> > +               return dev_err_probe(dev, error, "Failed touchscreen discover\n");
> > +
> > +       input_dev = devm_input_allocate_device(ts->dev);
> > +       if (!input_dev)
> > +               return -ENOMEM;
> > +
> > +       input_dev->name = "TouchNetix axiom Touchscreen";
> > +       input_dev->phys = "input/axiom_ts";
> > +
> > +       /* Single Touch */
> > +       input_set_abs_params(input_dev, ABS_X, 0, 65535, 0, 0);
> > +       input_set_abs_params(input_dev, ABS_Y, 0, 65535, 0, 0);
> > +
> > +       /* Multi Touch */
> > +       /* Min, Max, Fuzz (expected noise in px, try 4?) and Flat */
> > +       input_set_abs_params(input_dev, ABS_MT_POSITION_X, 0, 65535, 0, 0);
> > +       /* Min, Max, Fuzz (expected noise in px, try 4?) and Flat */
> > +       input_set_abs_params(input_dev, ABS_MT_POSITION_Y, 0, 65535, 0, 0);
> > +       input_set_abs_params(input_dev, ABS_MT_TOOL_TYPE, 0, MT_TOOL_MAX, 0, 0);
> > +       input_set_abs_params(input_dev, ABS_MT_DISTANCE, 0, 127, 0, 0);
> > +       input_set_abs_params(input_dev, ABS_MT_PRESSURE, 0, 127, 0, 0);
> > +
> > +       input_set_capability(input_dev, EV_KEY, BTN_TOUCH);
> > +
> > +       /* Registers the axiom device as a touchscreen instead of a mouse pointer */
> > +       error = input_mt_init_slots(input_dev, AXIOM_U41_MAX_TARGETS, INPUT_MT_DIRECT);
> > +       if (error)
> > +               return error;
> > +
> > +       /* Enables the raw data for up to 4 force channels to be sent to the input subsystem */
> > +       set_bit(EV_REL, input_dev->evbit);
> > +       set_bit(EV_MSC, input_dev->evbit);
> > +       /* Declare that we support "RAW" Miscellaneous events */
> > +       set_bit(MSC_RAW, input_dev->mscbit);
> > +
> > +       ts->input_dev = input_dev;
> > +       input_set_drvdata(ts->input_dev, ts);
> > +
> > +       /* Ensure that all reports are initialised to not be present. */
> > +       for (target = 0; target < AXIOM_U41_MAX_TARGETS; target++)
> > +               ts->targets[target].state = AXIOM_TARGET_STATE_NOT_PRESENT;
> > +
> > +       error = input_register_device(input_dev);
> > +       if (error)
> > +               return dev_err_probe(ts->dev, error,
> > +                                    "Could not register with Input Sub-system.\n");
> > +
> > +       error = devm_request_threaded_irq(dev, client->irq, NULL,
> > +                                         axiom_irq, IRQF_ONESHOT, dev_name(dev), ts);
> > +       if (error < 0) {
> > +               dev_warn(dev, "Request irq failed, falling back to polling mode");
> > +
> > +               error = input_setup_polling(input_dev, axiom_i2c_poll);
> > +               if (error)
> > +                       return dev_err_probe(ts->dev, error, "Unable to set up polling mode\n");
> > +
> > +               if (!device_property_read_u32(ts->dev, "poll-interval", &poll_interval))
> > +                       input_set_poll_interval(input_dev, poll_interval);
> > +               else
> > +                       input_set_poll_interval(input_dev, POLL_INTERVAL_DEFAULT_MS);
> > +       }
> > +
> > +       return 0;
> > +}
> > +
> > +static const struct i2c_device_id axiom_i2c_id_table[] = {
> > +       { "ax54a" },
> > +       {},
> > +};
> > +MODULE_DEVICE_TABLE(i2c, axiom_i2c_id_table);
> > +
> > +static const struct of_device_id axiom_i2c_of_match[] = {
> > +       { .compatible = "touchnetix,ax54a", },
> > +       { }
> > +};
> > +MODULE_DEVICE_TABLE(of, axiom_i2c_of_match);
> > +
> > +static struct i2c_driver axiom_i2c_driver = {
> > +       .driver = {
> > +                  .name = "axiom",
> > +                  .of_match_table = axiom_i2c_of_match,
> > +       },
> > +       .id_table = axiom_i2c_id_table,
> > +       .probe = axiom_i2c_probe,
> > +};
> > +module_i2c_driver(axiom_i2c_driver);
> > +MODULE_AUTHOR("Bart Prescott <bartp@baasheep.co.uk>");
> > +MODULE_AUTHOR("Pedro Torruella <pedro.torruella@touchnetix.com>");
> > +MODULE_AUTHOR("Mark Satterthwaite <mark.satterthwaite@touchnetix.com>");
> > +MODULE_AUTHOR("Hannah Rossiter <hannah.rossiter@touchnetix.com>");
> > +MODULE_AUTHOR("Kamel Bouhara <kamel.bouhara@bootlin.com>");
> > +MODULE_DESCRIPTION("TouchNetix axiom touchscreen I2C bus driver");
> > +MODULE_LICENSE("GPL");
> > --
> > 2.25.1
> >
>

--
Kamel Bouhara, Bootlin
Embedded Linux and kernel engineering
https://bootlin.com