| Message ID | 20201104203403.24937-1-digetx@gmail.com |
|---|---|
| Headers | show |
| Series | Introduce Embedded Controller driver for Acer A500 | expand |
On Wed, 04 Nov 2020, Dmitry Osipenko wrote: > Acer Iconia Tab A500 is an Android tablet device, it has ENE KB930 > Embedded Controller which provides battery-gauge, LED, GPIO and some > other functions. The EC uses firmware that is specifically customized > for Acer A500. This patch adds MFD driver for the Embedded Controller > which allows to power-off / reboot the A500 device, it also provides > a common register read/write API that will be used by the sub-devices. > > Signed-off-by: Dmitry Osipenko <digetx@gmail.com> > --- > drivers/mfd/Kconfig | 12 +++ > drivers/mfd/Makefile | 1 + > drivers/mfd/acer-ec-a500.c | 203 +++++++++++++++++++++++++++++++++++++ > 3 files changed, 216 insertions(+) > create mode 100644 drivers/mfd/acer-ec-a500.c > > diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig > index 8b99a13669bf..527ba5054d80 100644 > --- a/drivers/mfd/Kconfig > +++ b/drivers/mfd/Kconfig > @@ -2097,6 +2097,18 @@ config MFD_KHADAS_MCU > additional drivers must be enabled in order to use the functionality > of the device. > > +config MFD_ACER_A500_EC > + tristate "Embedded Controller driver for Acer Iconia Tab A500" Drop "driver". This is meant to be describing the device. > + depends on I2C depends on OF ? > + depends on ARCH_TEGRA_2x_SOC || COMPILE_TEST > + select MFD_CORE > + select REGMAP > + help > + Support for Acer Iconia Tab A500 Embedded Controller. > + > + The controller itself is ENE KB930, it is running firmware > + customized for the specific needs of the Acer A500 hardware. > + > menu "Multimedia Capabilities Port drivers" > depends on ARCH_SA1100 > > diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile > index 1780019d2474..7bfc57c8b363 100644 > --- a/drivers/mfd/Makefile > +++ b/drivers/mfd/Makefile > @@ -263,6 +263,7 @@ obj-$(CONFIG_MFD_ROHM_BD71828) += rohm-bd71828.o > obj-$(CONFIG_MFD_ROHM_BD718XX) += rohm-bd718x7.o > obj-$(CONFIG_MFD_STMFX) += stmfx.o > obj-$(CONFIG_MFD_KHADAS_MCU) += khadas-mcu.o > +obj-$(CONFIG_MFD_ACER_A500_EC) += acer-ec-a500.o > > obj-$(CONFIG_SGI_MFD_IOC3) += ioc3.o > obj-$(CONFIG_MFD_SIMPLE_MFD_I2C) += simple-mfd-i2c.o > diff --git a/drivers/mfd/acer-ec-a500.c b/drivers/mfd/acer-ec-a500.c > new file mode 100644 > index 000000000000..2785a6d9bcc4 > --- /dev/null > +++ b/drivers/mfd/acer-ec-a500.c > @@ -0,0 +1,203 @@ > +// SPDX-License-Identifier: GPL-2.0+ > +/* > + * MFD driver for Acer Iconia Tab A500 Embedded Controller. An "MFD" isn't a thing. Please describe the device. > + * Copyright 2020 GRATE-driver project. > + * > + * Based on downstream driver from Acer Inc. Most drivers are. Not sure this is required. > + */ > + > +#include <linux/delay.h> > +#include <linux/i2c.h> > +#include <linux/mfd/core.h> > +#include <linux/module.h> > +#include <linux/of_device.h> > +#include <linux/regmap.h> > +#include <linux/reboot.h> Alphabetical please. ;) > +#define A500_EC_I2C_ERR_TIMEOUT 500 > +#define A500_EC_POWER_CMD_TIMEOUT 1000 > + > +enum { > + REG_CURRENT_NOW = 0x03, > + REG_SHUTDOWN = 0x52, > + REG_WARM_REBOOT = 0x54, > + REG_COLD_REBOOT = 0x55, > +}; > + > +static struct i2c_client *a500_ec_client_pm_off; > + > +static int a500_ec_read(void *context, const void *reg_buf, size_t reg_size, > + void *val_buf, size_t val_sizel) > +{ > + struct i2c_client *client = context; > + unsigned int reg, retries = 5; > + u16 *ret_val = val_buf; > + s32 ret = 0; > + > + if (reg_size != 1 || val_sizel != 2) No magic numbers please. What does this *mean*? > + return -EOPNOTSUPP; Why EOPNOTSUPP? > + reg = *(u8 *)reg_buf; > + > + while (retries-- > 0) { > + ret = i2c_smbus_read_word_data(client, reg); > + if (ret >= 0) > + break; > + > + msleep(A500_EC_I2C_ERR_TIMEOUT); > + } > + > + if (ret < 0) { > + dev_err(&client->dev, "read 0x%x failed: %d\n", reg, ret); > + return ret; > + } > + > + *ret_val = ret; > + > + if (reg == REG_CURRENT_NOW) > + fsleep(10000); Ooo, new toy! > + return 0; > +} I'm surprised there isn't a generic function which does this kind of read. Seems like pretty common/boilerplate stuff. > +static int a500_ec_write(void *context, const void *data, size_t count) > +{ > + struct i2c_client *client = context; > + unsigned int reg, val, retries = 5; > + s32 ret = 0; > + > + if (count != 3) Define or comment needed. > + return -EOPNOTSUPP; > + > + reg = *(u8 *)(data + 0); > + val = *(u16 *)(data + 1); > + > + while (retries-- > 0) { > + ret = i2c_smbus_write_word_data(client, reg, val); > + if (ret >= 0) > + break; > + > + msleep(A500_EC_I2C_ERR_TIMEOUT); > + } > + > + if (ret < 0) { > + dev_err(&client->dev, "write 0x%x failed: %d\n", reg, ret); > + return ret; > + } > + > + return 0; > +} Again, seems pretty boilerplate. Are you sure there isn't a helper? > +static const struct regmap_config a500_ec_regmap_config = { > + .name = "KB930", > + .reg_bits = 8, > + .val_bits = 16, > + .max_register = 0xff, > +}; > + > +static const struct regmap_bus a500_ec_regmap_bus = { > + .reg_format_endian_default = REGMAP_ENDIAN_NATIVE, > + .val_format_endian_default = REGMAP_ENDIAN_LITTLE, > + .write = a500_ec_write, > + .read = a500_ec_read, > + .max_raw_read = 2, > +}; > + > +static void a500_ec_poweroff(void) > +{ > + i2c_smbus_write_word_data(a500_ec_client_pm_off, REG_SHUTDOWN, 0); > + > + mdelay(A500_EC_POWER_CMD_TIMEOUT); > +} > + > +static int a500_ec_restart_notify(struct notifier_block *this, > + unsigned long reboot_mode, void *data) > +{ > + if (reboot_mode == REBOOT_WARM) > + i2c_smbus_write_word_data(a500_ec_client_pm_off, > + REG_WARM_REBOOT, 0); > + else > + i2c_smbus_write_word_data(a500_ec_client_pm_off, > + REG_COLD_REBOOT, 1); What's with the magic '0' and '1's at the end? > + mdelay(A500_EC_POWER_CMD_TIMEOUT); > + > + return NOTIFY_DONE; > +} > + > +static struct notifier_block a500_ec_restart_handler = { > + .notifier_call = a500_ec_restart_notify, > + .priority = 200, > +}; > + > +static const struct mfd_cell a500_ec_cells[] = { > + { .name = "acer-a500-iconia-battery", }, > + { .name = "acer-a500-iconia-leds", }, > +}; > + > +static int a500_ec_probe(struct i2c_client *client) > +{ > + struct regmap *rmap; 'rmap' barely makes the top 10: $ git grep -ho "struct regmap \*[a-z]*" | sort | uniq -c | sort -rn | head 1814 struct regmap *regmap 581 struct regmap *map 97 struct regmap * 50 struct regmap *syscon 50 struct regmap *r 35 struct regmap *reg 34 struct regmap *cfgchip 32 struct regmap *grf 30 struct regmap *rmap 27 struct regmap *base Please use regmap here. > + int err; > + > + rmap = devm_regmap_init(&client->dev, &a500_ec_regmap_bus, > + client, &a500_ec_regmap_config); > + if (IS_ERR(rmap)) > + return PTR_ERR(rmap); > + > + /* register battery and LED sub-devices */ This comment is superfluous and is just the type of documentation that becomes out-of-date quickly. > + err = devm_mfd_add_devices(&client->dev, PLATFORM_DEVID_AUTO, > + a500_ec_cells, ARRAY_SIZE(a500_ec_cells), > + NULL, 0, NULL); > + if (err) { > + dev_err(&client->dev, "failed to add sub-devices: %d\n", err); > + return err; > + } > + > + /* set up power management functions */ We know what "power" and "pm" mean. You can safely remove this comment. > + if (of_device_is_system_power_controller(client->dev.of_node)) { > + a500_ec_client_pm_off = client; > + > + err = register_restart_handler(&a500_ec_restart_handler); > + if (err) > + return err; > + > + if (!pm_power_off) > + pm_power_off = a500_ec_poweroff; > + } > + > + return 0; > +} > + > +static int a500_ec_remove(struct i2c_client *client) > +{ > + if (of_device_is_system_power_controller(client->dev.of_node)) { > + if (pm_power_off == a500_ec_poweroff) > + pm_power_off = NULL; > + > + unregister_restart_handler(&a500_ec_restart_handler); > + } > + > + return 0; > +} > + > +static const struct of_device_id a500_ec_match[] = { > + { .compatible = "acer,a500-iconia-ec" }, > + { } > +}; > +MODULE_DEVICE_TABLE(of, a500_ec_match); > + > +static struct i2c_driver a500_ec_driver = { > + .driver = { > + .name = "acer-a500-embedded-controller", > + .of_match_table = a500_ec_match, > + }, > + .probe_new = a500_ec_probe, > + .remove = a500_ec_remove, > +}; > +module_i2c_driver(a500_ec_driver); > + > +MODULE_DESCRIPTION("Acer Iconia Tab A500 Embedded Controller driver"); > +MODULE_AUTHOR("Dmitry Osipenko <digetx@gmail.com>"); > +MODULE_LICENSE("GPL"); -- Lee Jones [李琼斯] Senior Technical Lead - Developer Services Linaro.org │ Open source software for Arm SoCs Follow Linaro: Facebook | Twitter | Blog
13.11.2020 12:37, Lee Jones пишет: ... >> +config MFD_ACER_A500_EC >> + tristate "Embedded Controller driver for Acer Iconia Tab A500" > > Drop "driver". This is meant to be describing the device. > >> + depends on I2C > > depends on OF ? ... >> + depends on ARCH_TEGRA_2x_SOC || COMPILE_TEST >> + select MFD_CORE >> + select REGMAP >> + help ARCH_TEGRA_2x_SOC selects OF. For COMPILE_TEST it doesn't matter since OF framework provides stubs for !OF. ... >> +static int a500_ec_read(void *context, const void *reg_buf, size_t reg_size, >> + void *val_buf, size_t val_sizel) >> +{ >> + struct i2c_client *client = context; >> + unsigned int reg, retries = 5; >> + u16 *ret_val = val_buf; >> + s32 ret = 0; >> + >> + if (reg_size != 1 || val_sizel != 2) > > No magic numbers please. > > What does this *mean*? These are the size of address register and size of a read value, both in bytes. >> + return -EOPNOTSUPP; > > Why EOPNOTSUPP? Other sizes aren't supported by embedded controller. Although, perhaps this check isn't really needed at all since the sizes are already expressed in the a500_ec_regmap_config. I'll need to take a closer look at why this size-checking was added because don't quite remember already. If it's not needed, then I'll remove it in the next revision, otherwise will add a clarifying comment. >> + reg = *(u8 *)reg_buf; >> + >> + while (retries-- > 0) { >> + ret = i2c_smbus_read_word_data(client, reg); >> + if (ret >= 0) >> + break; >> + >> + msleep(A500_EC_I2C_ERR_TIMEOUT); >> + } >> + >> + if (ret < 0) { >> + dev_err(&client->dev, "read 0x%x failed: %d\n", reg, ret); >> + return ret; >> + } >> + >> + *ret_val = ret; >> + >> + if (reg == REG_CURRENT_NOW) >> + fsleep(10000); > > Ooo, new toy! > >> + return 0; >> +} > > I'm surprised there isn't a generic function which does this kind of > read. Seems like pretty common/boilerplate stuff. I'm not quite sure that this is a really very common pattern which deserves a generic helper. ... >> +static int a500_ec_restart_notify(struct notifier_block *this, >> + unsigned long reboot_mode, void *data) >> +{ >> + if (reboot_mode == REBOOT_WARM) >> + i2c_smbus_write_word_data(a500_ec_client_pm_off, >> + REG_WARM_REBOOT, 0); >> + else >> + i2c_smbus_write_word_data(a500_ec_client_pm_off, >> + REG_COLD_REBOOT, 1); > > What's with the magic '0' and '1's at the end? These are the values which controller's firmware wants to see, otherwise it will reject command as invalid. I'll add a clarifying comment to the code. Thank you for the review. I'll address all the comments in the v7.
On Mon, 16 Nov 2020, Dmitry Osipenko wrote: > 13.11.2020 12:37, Lee Jones пишет: > ... > >> +config MFD_ACER_A500_EC > >> + tristate "Embedded Controller driver for Acer Iconia Tab A500" > > > > Drop "driver". This is meant to be describing the device. > > > >> + depends on I2C > > > > depends on OF ? > ... > >> + depends on ARCH_TEGRA_2x_SOC || COMPILE_TEST > >> + select MFD_CORE > >> + select REGMAP > >> + help > > ARCH_TEGRA_2x_SOC selects OF. > > For COMPILE_TEST it doesn't matter since OF framework provides stubs for > !OF. I always thought it was best to be explicit. > ... > >> +static int a500_ec_read(void *context, const void *reg_buf, size_t reg_size, > >> + void *val_buf, size_t val_sizel) > >> +{ > >> + struct i2c_client *client = context; > >> + unsigned int reg, retries = 5; > >> + u16 *ret_val = val_buf; > >> + s32 ret = 0; > >> + > >> + if (reg_size != 1 || val_sizel != 2) > > > > No magic numbers please. > > > > What does this *mean*? > > These are the size of address register and size of a read value, both in > bytes. Great. But don't tell me that. You need to tell the next person who reads this code, and the next, and the next. Defines work best for this. Comments are also okay. > >> + return -EOPNOTSUPP; > > > > Why EOPNOTSUPP? > > Other sizes aren't supported by embedded controller. > > Although, perhaps this check isn't really needed at all since the sizes > are already expressed in the a500_ec_regmap_config. > > I'll need to take a closer look at why this size-checking was added > because don't quite remember already. If it's not needed, then I'll > remove it in the next revision, otherwise will add a clarifying comment. "Operation not supported on transport endpoint" doesn't seem like a good fit here. If the check says, please consider changing it to something like -EINVAL. > >> + reg = *(u8 *)reg_buf; > >> + > >> + while (retries-- > 0) { > >> + ret = i2c_smbus_read_word_data(client, reg); > >> + if (ret >= 0) > >> + break; > >> + > >> + msleep(A500_EC_I2C_ERR_TIMEOUT); > >> + } > >> + > >> + if (ret < 0) { > >> + dev_err(&client->dev, "read 0x%x failed: %d\n", reg, ret); > >> + return ret; > >> + } > >> + > >> + *ret_val = ret; > >> + > >> + if (reg == REG_CURRENT_NOW) > >> + fsleep(10000); > > > > Ooo, new toy! > > > >> + return 0; > >> +} > > > > I'm surprised there isn't a generic function which does this kind of > > read. Seems like pretty common/boilerplate stuff. > > I'm not quite sure that this is a really very common pattern which > deserves a generic helper. What? Read from I2C a few times, then sleep sounds like a pretty common pattern to me. > ... > >> +static int a500_ec_restart_notify(struct notifier_block *this, > >> + unsigned long reboot_mode, void *data) > >> +{ > >> + if (reboot_mode == REBOOT_WARM) > >> + i2c_smbus_write_word_data(a500_ec_client_pm_off, > >> + REG_WARM_REBOOT, 0); > >> + else > >> + i2c_smbus_write_word_data(a500_ec_client_pm_off, > >> + REG_COLD_REBOOT, 1); > > > > What's with the magic '0' and '1's at the end? > > These are the values which controller's firmware wants to see, otherwise > it will reject command as invalid. I'll add a clarifying comment to the > code. Thanks. Hopefully with a bit more information as to why the firmware expects to see them. Hopefully they're not random. -- Lee Jones [李琼斯] Senior Technical Lead - Developer Services Linaro.org │ Open source software for Arm SoCs Follow Linaro: Facebook | Twitter | Blog
16.11.2020 11:48, Lee Jones пишет: >>>> +config MFD_ACER_A500_EC >>>> + tristate "Embedded Controller driver for Acer Iconia Tab A500" >>> >>> Drop "driver". This is meant to be describing the device. >>> >>>> + depends on I2C >>> >>> depends on OF ? >> ... >>>> + depends on ARCH_TEGRA_2x_SOC || COMPILE_TEST >>>> + select MFD_CORE >>>> + select REGMAP >>>> + help >> >> ARCH_TEGRA_2x_SOC selects OF. >> >> For COMPILE_TEST it doesn't matter since OF framework provides stubs for >> !OF. > > I always thought it was best to be explicit. Alright, I see that the OF selection is all over the MFD Kconfig, hence let's keep it consistent. I also prefer the explicit variant more, but some other kernel maintainers may disagree. >> ... >>> Why EOPNOTSUPP? >> >> Other sizes aren't supported by embedded controller. >> >> Although, perhaps this check isn't really needed at all since the sizes >> are already expressed in the a500_ec_regmap_config. >> >> I'll need to take a closer look at why this size-checking was added >> because don't quite remember already. If it's not needed, then I'll >> remove it in the next revision, otherwise will add a clarifying comment. > > "Operation not supported on transport endpoint" doesn't seem like a > good fit here. If the check says, please consider changing it to > something like -EINVAL. The regmap core code performs all the necessary checks before driver's code is reached, perhaps I just overlooked something before. Hence it will be removed in the next revision. ... >>>> + while (retries-- > 0) { >>>> + ret = i2c_smbus_read_word_data(client, reg); >>>> + if (ret >= 0) >>>> + break; >>>> + >>>> + msleep(A500_EC_I2C_ERR_TIMEOUT); >>>> + } ... >>> I'm surprised there isn't a generic function which does this kind of >>> read. Seems like pretty common/boilerplate stuff. >> >> I'm not quite sure that this is a really very common pattern which >> deserves a generic helper. > > What? Read from I2C a few times, then sleep sounds like a pretty > common pattern to me. Maybe the read_poll_timeout() helper could be used for that, but I think the open-coded variant is much easier to perceive, don't you agree? >> ... >>>> +static int a500_ec_restart_notify(struct notifier_block *this, >>>> + unsigned long reboot_mode, void *data) >>>> +{ >>>> + if (reboot_mode == REBOOT_WARM) >>>> + i2c_smbus_write_word_data(a500_ec_client_pm_off, >>>> + REG_WARM_REBOOT, 0); >>>> + else >>>> + i2c_smbus_write_word_data(a500_ec_client_pm_off, >>>> + REG_COLD_REBOOT, 1); >>> >>> What's with the magic '0' and '1's at the end? >> >> These are the values which controller's firmware wants to see, otherwise >> it will reject command as invalid. I'll add a clarifying comment to the >> code. > > Thanks. Hopefully with a bit more information as to why the firmware > expects to see them. Hopefully they're not random. > These are the firmware-defined specific command opcodes, I'll add defines for them to make it more clear, thanks.
On Mon, 16 Nov 2020, Dmitry Osipenko wrote: > ... > >>>> + while (retries-- > 0) { > >>>> + ret = i2c_smbus_read_word_data(client, reg); > >>>> + if (ret >= 0) > >>>> + break; > >>>> + > >>>> + msleep(A500_EC_I2C_ERR_TIMEOUT); > >>>> + } > ... > >>> I'm surprised there isn't a generic function which does this kind of > >>> read. Seems like pretty common/boilerplate stuff. > >> > >> I'm not quite sure that this is a really very common pattern which > >> deserves a generic helper. > > > > What? Read from I2C a few times, then sleep sounds like a pretty > > common pattern to me. > > Maybe the read_poll_timeout() helper could be used for that, but I think > the open-coded variant is much easier to perceive, don't you agree? I haven't looked into it. My comment was more general in nature. As a general rule, helpers are better than open coding, but there are always exceptions. There may not even be a suitable helper for this use-case. As I say, the comment was more of a passing remark. [...] > >> These are the values which controller's firmware wants to see, otherwise > >> it will reject command as invalid. I'll add a clarifying comment to the > >> code. > > > > Thanks. Hopefully with a bit more information as to why the firmware > > expects to see them. Hopefully they're not random. > > These are the firmware-defined specific command opcodes, I'll add > defines for them to make it more clear, thanks. That'll do. -- Lee Jones [李琼斯] Senior Technical Lead - Developer Services Linaro.org │ Open source software for Arm SoCs Follow Linaro: Facebook | Twitter | Blog
Hello! This series adds support for the Embedded Controller which is found on Acer Iconia Tab A500 (Android tablet device). The Embedded Controller is ENE KB930 and it's running firmware customized for the A500. The firmware interface may be reused by some other sibling Acer tablets, although none of those tablets are supported in upstream yet. Changelog: v5: - No changes. Re-sending again in order to check whether dtschema-bot warning is resolved now, which didn't happen in v4 because bot used older 5.9 kernel code base instead of 5.10. v4: - No code changes. Added r-b from Rob Herring and Sebastian Reichel. Re-sending for 5.11. - The v3 of LED driver was applied by Pavel Machek and already presents in v5.10 kernel. v3: - Rebased on a recent linux-next. Fixed new merge conflict and dropped "regmap: Use flexible sleep" patch because it's already applied. v2: - Factored out KB930 device-tree binding into a separate file, like it was suggested by Lubomir Rintel. - Switched to use regmap API like it was suggested by Lubomir Rintel. - Added patch "regmap: Use flexible sleep" which allows not to hog CPU while LED is switching state. - Corrected MODULE_LICENSE to use "GPL" in all patches. - Corrected MFD driver Kconfig entry like it was suggested by Lubomir Rintel, it now depends on I2C. - Switched to use I2C probe_new() in the MFD driver. - Renamed the global pm_off variable, like it was suggested by Lubomir Rintel and Lee Jones. - Dropped serial number from the battery driver because I realized that it's not a battery serial, but a device serial. - Battery driver now uses dev_err_probe(), like it was suggested by Sebastian Reichel. - Dropped legacy LED_ON usage from the LED driver and renamed the LEDs, like it was suggested by Pavel Machek. I also checked whether LED-name customization via device-tree could be needed by other potentially compatible devices and it shouldn't be needed, anyways it won't be difficult to extend the code even if I'm wrong. Dmitry Osipenko (4): dt-bindings: mfd: Add ENE KB930 Embedded Controller binding mfd: Add driver for Embedded Controller found on Acer Iconia Tab A500 power: supply: Add battery gauge driver for Acer Iconia Tab A500 ARM: tegra: acer-a500: Add Embedded Controller .../devicetree/bindings/mfd/ene-kb930.yaml | 66 ++++ .../boot/dts/tegra20-acer-a500-picasso.dts | 17 + drivers/mfd/Kconfig | 12 + drivers/mfd/Makefile | 1 + drivers/mfd/acer-ec-a500.c | 203 ++++++++++++ drivers/power/supply/Kconfig | 6 + drivers/power/supply/Makefile | 1 + drivers/power/supply/acer_a500_battery.c | 297 ++++++++++++++++++ 8 files changed, 603 insertions(+) create mode 100644 Documentation/devicetree/bindings/mfd/ene-kb930.yaml create mode 100644 drivers/mfd/acer-ec-a500.c create mode 100644 drivers/power/supply/acer_a500_battery.c