Commit d5b4fd6e authored by Jonas Jelonek's avatar Jonas Jelonek Committed by Andi Shyti
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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: default avatarJonas Jelonek <jelonek.jonas@gmail.com>
Tested-by: default avatarSven Eckelmann <sven@narfation.org>
Reviewed-by: default avatarChris Packham <chris.packham@alliedtelesis.co.nz>
Tested-by: Chris Packham <chris.packham@alliedtelesis.co.nz> # On RTL9302C based board
Tested-by: default avatarMarkus Stockhausen <markus.stockhausen@gmx.de>
Signed-off-by: default avatarAndi Shyti <andi.shyti@kernel.org>
Link: https://lore.kernel.org/r/20250927101931.71575-6-jelonek.jonas@gmail.com
parent d1cef7af

drivers/i2c/busses/i2c-rtl9300.c

+6 −5
Original line number Diff line number Diff line
@@ -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;

}