From 3b384bd6c3f2d6d3526c77bfb264dfbaf737bc2a Mon Sep 17 00:00:00 2001 From: Furquan Shaikh Date: Sun, 6 Dec 2020 22:05:13 -0800 Subject: [PATCH] Input: raydium_ts_i2c - do not split tx transactions Raydium device does not like splitting of tx transactions into multiple messages - one for the register address and one for the actual data. This results in incorrect behavior on the device side. This change updates raydium_i2c_read and raydium_i2c_write to create i2c_msg arrays separately and passes those arrays into raydium_i2c_xfer which decides based on the address whether the bank switch command should be sent. The bank switch header is still added by raydium_i2c_read and raydium_i2c_write to ensure that all these operations are performed as part of a single I2C transfer. It guarantees that no other transactions are initiated to any other device on the same bus after the bank switch command is sent. Signed-off-by: Furquan Shaikh Link: https://lore.kernel.org/r/20201205005941.1427643-1-furquan@google.com Signed-off-by: Dmitry Torokhov --- drivers/input/touchscreen/raydium_i2c_ts.c | 126 ++++++++++++++++++++--------- 1 file changed, 88 insertions(+), 38 deletions(-) diff --git a/drivers/input/touchscreen/raydium_i2c_ts.c b/drivers/input/touchscreen/raydium_i2c_ts.c index e694a9b..603a948 100644 --- a/drivers/input/touchscreen/raydium_i2c_ts.c +++ b/drivers/input/touchscreen/raydium_i2c_ts.c @@ -137,45 +137,25 @@ struct raydium_data { bool wake_irq_enabled; }; -static int raydium_i2c_xfer(struct i2c_client *client, - u32 addr, void *data, size_t len, bool is_read) -{ - struct raydium_bank_switch_header { - u8 cmd; - __be32 be_addr; - } __packed header = { - .cmd = RM_CMD_BANK_SWITCH, - .be_addr = cpu_to_be32(addr), - }; - - u8 reg_addr = addr & 0xff; - - struct i2c_msg xfer[] = { - { - .addr = client->addr, - .len = sizeof(header), - .buf = (u8 *)&header, - }, - { - .addr = client->addr, - .len = 1, - .buf = ®_addr, - }, - { - .addr = client->addr, - .len = len, - .buf = data, - .flags = is_read ? I2C_M_RD : 0, - } - }; +/* + * Header to be sent for RM_CMD_BANK_SWITCH command. This is used by + * raydium_i2c_{read|send} below. + */ +struct __packed raydium_bank_switch_header { + u8 cmd; + __be32 be_addr; +}; +static int raydium_i2c_xfer(struct i2c_client *client, u32 addr, + struct i2c_msg *xfer, size_t xfer_count) +{ + int ret; /* * If address is greater than 255, then RM_CMD_BANK_SWITCH needs to be * sent first. Else, skip the header i.e. xfer[0]. */ int xfer_start_idx = (addr > 0xff) ? 0 : 1; - size_t xfer_count = ARRAY_SIZE(xfer) - xfer_start_idx; - int ret; + xfer_count -= xfer_start_idx; ret = i2c_transfer(client->adapter, &xfer[xfer_start_idx], xfer_count); if (likely(ret == xfer_count)) @@ -189,10 +169,46 @@ static int raydium_i2c_send(struct i2c_client *client, { int tries = 0; int error; + u8 *tx_buf; + u8 reg_addr = addr & 0xff; + + tx_buf = kmalloc(len + 1, GFP_KERNEL); + if (!tx_buf) + return -ENOMEM; + + tx_buf[0] = reg_addr; + memcpy(tx_buf + 1, data, len); do { - error = raydium_i2c_xfer(client, addr, (void *)data, len, - false); + struct raydium_bank_switch_header header = { + .cmd = RM_CMD_BANK_SWITCH, + .be_addr = cpu_to_be32(addr), + }; + + /* + * 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 + * issues. This is also why regmap infrastructure cannot be used + * for this driver. Regmap handles page(bank) switch and reads + * as separate i2c_transfer() operations. This can result in + * problems if the Raydium device is on a shared I2C bus. + */ + struct i2c_msg xfer[] = { + { + .addr = client->addr, + .len = sizeof(header), + .buf = (u8 *)&header, + }, + { + .addr = client->addr, + .len = len + 1, + .buf = tx_buf, + }, + }; + + error = raydium_i2c_xfer(client, addr, xfer, ARRAY_SIZE(xfer)); if (likely(!error)) return 0; @@ -206,12 +222,46 @@ static int raydium_i2c_send(struct i2c_client *client, static int raydium_i2c_read(struct i2c_client *client, u32 addr, void *data, size_t len) { - size_t xfer_len; int error; while (len) { - xfer_len = min_t(size_t, len, RM_MAX_READ_SIZE); - error = raydium_i2c_xfer(client, addr, data, xfer_len, true); + u8 reg_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 + * issues. This is also why regmap infrastructure cannot be used + * for this driver. Regmap handles page(bank) switch and writes + * as separate i2c_transfer() operations. This can result in + * problems if the Raydium device is on a shared I2C bus. + */ + struct i2c_msg xfer[] = { + { + .addr = client->addr, + .len = sizeof(header), + .buf = (u8 *)&header, + }, + { + .addr = client->addr, + .len = 1, + .buf = ®_addr, + }, + { + .addr = client->addr, + .len = xfer_len, + .buf = data, + .flags = I2C_M_RD, + } + }; + + error = raydium_i2c_xfer(client, addr, xfer, ARRAY_SIZE(xfer)); if (unlikely(error)) return error; -- 2.7.4