From d5b4fd6ed8ea3eb5dc072285a5e4c0ee32e829b2 Mon Sep 17 00:00:00 2001 From: Jonas Jelonek Date: Sat, 27 Sep 2025 10:19:27 +0000 Subject: [PATCH] i2c: rtl9300: do not set read mode on every transfer Move the operation to set the read mode from config_xfer to probe. The I2C controller of RTL9300 and RTL9310 support a legacy message mode for READs with 'Read Address Data' instead of the standard format 'Write Address ; Read Data'. There is no way to pass that via smbus_xfer, thus there is no point in supported this in the driver and moreover no point in setting this on every transaction. Setting this once in the probe call is sufficient. Signed-off-by: Jonas Jelonek Tested-by: Sven Eckelmann Reviewed-by: Chris Packham Tested-by: Chris Packham # On RTL9302C based board Tested-by: Markus Stockhausen Signed-off-by: Andi Shyti Link: https://lore.kernel.org/r/20250927101931.71575-6-jelonek.jonas@gmail.com --- drivers/i2c/busses/i2c-rtl9300.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) diff --git a/drivers/i2c/busses/i2c-rtl9300.c b/drivers/i2c/busses/i2c-rtl9300.c index 4177cfb770948..9e3517b09b3d2 100644 --- a/drivers/i2c/busses/i2c-rtl9300.c +++ b/drivers/i2c/busses/i2c-rtl9300.c @@ -130,11 +130,7 @@ static int rtl9300_i2c_config_xfer(struct rtl9300_i2c *i2c, struct rtl9300_i2c_c if (ret) return ret; - ret = regmap_field_write(i2c->fields[F_DATA_WIDTH], (len - 1) & 0xf); - if (ret) - return ret; - - return regmap_field_write(i2c->fields[F_RD_MODE], 0); + return regmap_field_write(i2c->fields[F_DATA_WIDTH], (len - 1) & 0xf); } static int rtl9300_i2c_read(struct rtl9300_i2c *i2c, u8 *buf, int len) @@ -455,6 +451,11 @@ static int rtl9300_i2c_probe(struct platform_device *pdev) } i2c->sda_num = 0xff; + /* only use standard read format */ + ret = regmap_field_write(i2c->fields[F_RD_MODE], 0); + if (ret) + return ret; + return 0; } -- 2.47.3