@@ -111,6 +111,15 @@ struct raydium_info {
u8 y_res; /* units/mm */
};
+/*
+ * Header to be sent for RM_CMD_BANK_SWITCH command. This is used by
+ * raydium_i2c_{read|send}_message below.
+ */
+struct __packed raydium_bank_switch_header {
+ u8 cmd;
+ __be32 be_addr;
+};
+
/* struct raydium_data - represents state of Raydium touchscreen device */
struct raydium_data {
struct i2c_client *client;
@@ -198,22 +207,44 @@ static int raydium_i2c_read(struct i2c_client *client,
static int raydium_i2c_read_message(struct i2c_client *client,
u32 addr, void *data, size_t len)
{
- __be32 be_addr;
- size_t xfer_len;
- int error;
+ int ret;
while (len) {
- xfer_len = min_t(size_t, len, RM_MAX_READ_SIZE);
-
- be_addr = cpu_to_be32(addr);
+ u8 read_addr = addr & 0xff;
+ struct raydium_bank_switch_header header = {
+ .cmd = RM_CMD_BANK_SWITCH,
+ .be_addr = cpu_to_be32(addr),
+ };
+ size_t xfer_len = min_t(size_t, len, RM_MAX_READ_SIZE);
+ /*
+ * Perform as a single i2c_transfer transaction to ensure that
+ * no other I2C transactions are initiated on the bus to any
+ * other device in between. Initiating transacations to other
+ * devices after RM_CMD_BANK_SWITCH is sent is known to cause
+ * read issues.
+ */
+ struct i2c_msg xfer[] = {
+ {
+ .addr = client->addr,
+ .len = sizeof(header),
+ .buf = (u8 *)&header,
+ },
+ {
+ .addr = client->addr,
+ .len = 1,
+ .buf = &read_addr,
+ },
+ {
+ .addr = client->addr,
+ .flags = I2C_M_RD,
+ .len = xfer_len,
+ .buf = data,
+ }
+ };
- error = raydium_i2c_send(client, RM_CMD_BANK_SWITCH,
- &be_addr, sizeof(be_addr));
- if (!error)
- error = raydium_i2c_read(client, addr & 0xff,
- data, xfer_len);
- if (error)
- return error;
+ ret = i2c_transfer(client->adapter, xfer, ARRAY_SIZE(xfer));
+ if (ret != ARRAY_SIZE(xfer))
+ return ret < 0 ? ret : -EIO;
len -= xfer_len;
data += xfer_len;
@@ -224,22 +255,49 @@ static int raydium_i2c_read_message(struct i2c_client *client,
}
static int raydium_i2c_send_message(struct i2c_client *client,
- u32 addr, const void *data, size_t len)
+ u32 addr, void *data, size_t len)
{
- __be32 be_addr = cpu_to_be32(addr);
- int error;
+ int tries = 0;
- error = raydium_i2c_send(client, RM_CMD_BANK_SWITCH,
- &be_addr, sizeof(be_addr));
- if (!error)
- error = raydium_i2c_send(client, addr & 0xff, data, len);
+ do {
+ int ret;
+ u8 write_addr = addr & 0xff;
+ struct raydium_bank_switch_header header = {
+ .cmd = RM_CMD_BANK_SWITCH,
+ .be_addr = cpu_to_be32(addr),
+ };
+
+ struct i2c_msg xfer[] = {
+ {
+ .addr = client->addr,
+ .len = sizeof(header),
+ .buf = (u8 *)&header,
+ },
+ {
+ .addr = client->addr,
+ .len = 1,
+ .buf = &write_addr,
+ },
+ {
+ .addr = client->addr,
+ .len = len,
+ .buf = data,
+ }
+ };
- return error;
+ ret = i2c_transfer(client->adapter, xfer, ARRAY_SIZE(xfer));
+ if (likely(ret == ARRAY_SIZE(xfer)))
+ return 0;
+
+ msleep(20);
+ } while (++tries < RM_MAX_RETRIES);
+
+ return -EIO;
}
static int raydium_i2c_sw_reset(struct i2c_client *client)
{
- const u8 soft_rst_cmd = 0x01;
+ u8 soft_rst_cmd = 0x01;
int error;
error = raydium_i2c_send_message(client, RM_RESET_MSG_ADDR,
On an AMD chromebook, where the same I2C bus is shared by both Raydium touchscreen and a trackpad device, it is observed that interleaving of I2C messages when raydium_i2c_read_message() is called leads to the Raydium touch IC reporting incorrect information. This is the sequence that was observed to result in the above issue: * I2C write to Raydium device for RM_CMD_BANK_SWITCH * I2C write to trackpad device * I2C read from trackpad device * I2C write to Raydium device for setting address * I2C read from Raydium device >>>> This provides incorrect information This change updates raydium_i2c_read_message and raydium_i2c_send_message to perform all the I2C transfers in the function as part of a single i2c_transfer transaction. This ensures that no transactions are initiated to any other device on the same bus in between and hence the information obtained from the touchscreen device is correct. Verified with the patch across multiple reboots (>100) that the information reported by the Raydium touchscreen device during probe is correct. Signed-off-by: Furquan Shaikh <furquan@google.com> --- drivers/input/touchscreen/raydium_i2c_ts.c | 102 ++++++++++++++++----- 1 file changed, 80 insertions(+), 22 deletions(-)