Move the register operation to set the SCL frequency to the
rtl9300_i2c_config_io function instead of the rtl9300_i2c_config_xfer
function. This rather belongs there next to selecting the current SDA
output line.

Signed-off-by: Jonas Jelonek <jelonek.jonas@gmail.com>
---
 drivers/i2c/busses/i2c-rtl9300.c | 17 +++++++++--------
 1 file changed, 9 insertions(+), 8 deletions(-)

diff --git a/drivers/i2c/busses/i2c-rtl9300.c b/drivers/i2c/busses/i2c-rtl9300.c
index ead5aa6e60f8..8e8e98108750 100644
--- a/drivers/i2c/busses/i2c-rtl9300.c
+++ b/drivers/i2c/busses/i2c-rtl9300.c
@@ -95,18 +95,23 @@ static int rtl9300_i2c_select_scl(struct rtl9300_i2c *i2c, u8 scl)
 	return regmap_field_write(i2c->fields[F_SCL_SEL], 1);
 }
 
-static int rtl9300_i2c_config_io(struct rtl9300_i2c *i2c, u8 sda_pin)
+static int rtl9300_i2c_config_io(struct rtl9300_i2c *i2c, struct rtl9300_i2c_chan *chan)
 {
 	struct rtl9300_i2c_drv_data *drv_data;
 	int ret;
 
 	drv_data = (struct rtl9300_i2c_drv_data *)device_get_match_data(i2c->dev);
 
-	ret = regmap_field_update_bits(i2c->fields[F_SDA_SEL], BIT(sda_num), BIT(sda_num));
+	ret = regmap_field_update_bits(i2c->fields[F_SDA_SEL], BIT(chan->sda_num),
+				       BIT(chan->sda_num));
 	if (ret)
 		return ret;
 
-	ret = regmap_field_write(i2c->fields[F_SDA_OUT_SEL], sda_num);
+	ret = regmap_field_write(i2c->fields[F_SDA_OUT_SEL], chan->sda_num);
+	if (ret)
+		return ret;
+
+	ret = regmap_field_write(i2c->fields[F_SCL_FREQ], chan->bus_freq);
 	if (ret)
 		return ret;
 
@@ -121,10 +126,6 @@ static int rtl9300_i2c_config_xfer(struct rtl9300_i2c *i2c, struct rtl9300_i2c_c
 	if (len < 1 || len > 16)
 		return -EINVAL;
 
-	ret = regmap_field_write(i2c->fields[F_SCL_FREQ], chan->bus_freq);
-	if (ret)
-		return ret;
-
 	ret = regmap_field_write(i2c->fields[F_DEV_ADDR], addr);
 	if (ret)
 		return ret;
@@ -244,7 +245,7 @@ static int rtl9300_i2c_smbus_xfer(struct i2c_adapter *adap, u16 addr, unsigned s
 
 	mutex_lock(&i2c->lock);
 	if (chan->sda_num != i2c->sda_num) {
-		ret = rtl9300_i2c_config_io(i2c, chan->sda_pin);
+		ret = rtl9300_i2c_config_io(i2c, chan);
 		if (ret)
 			goto out_unlock;
 		i2c->sda_num = chan->sda_num;
-- 
2.48.1

…
> +++ b/drivers/i2c/busses/i2c-rtl9300.c
…
> +static int mshv_vtl_sint_ioctl_set_eventfd(struct mshv_vtl_set_eventfd __user *arg)
> +{
…
> @@ -244,7 +245,7 @@ static int rtl9300_i2c_smbus_xfer(struct i2c_adapter *adap, u16 addr, unsigned s
>  
>  	mutex_lock(&i2c->lock);
>  	if (chan->sda_num != i2c->sda_num) {
> -		ret = rtl9300_i2c_config_io(i2c, chan->sda_pin);
> +		ret = rtl9300_i2c_config_io(i2c, chan);
>  		if (ret)
>  			goto out_unlock;
…

Under which circumstances would you become interested to apply a statement
like “guard(mutex)(&i2c->lock);”?
https://elixir.bootlin.com/linux/v6.16/source/include/linux/mutex.h#L225

Regards,
Markus

On 10.08.2025 10:49, Markus Elfring wrote:
> …
>> +++ b/drivers/i2c/busses/i2c-rtl9300.c
> …
>> +static int mshv_vtl_sint_ioctl_set_eventfd(struct mshv_vtl_set_eventfd __user *arg)
>> +{
> …
>> @@ -244,7 +245,7 @@ static int rtl9300_i2c_smbus_xfer(struct i2c_adapter *adap, u16 addr, unsigned s
>>  
>>  	mutex_lock(&i2c->lock);
>>  	if (chan->sda_num != i2c->sda_num) {
>> -		ret = rtl9300_i2c_config_io(i2c, chan->sda_pin);
>> +		ret = rtl9300_i2c_config_io(i2c, chan);
>>  		if (ret)
>>  			goto out_unlock;
> …
>
> Under which circumstances would you become interested to apply a statement
> like “guard(mutex)(&i2c->lock);”?
> https://elixir.bootlin.com/linux/v6.16/source/include/linux/mutex.h#L225

Didn't know about that before but no objections against it. Can integrate that
in the next version.

The link Sven posted was quite helpful on that, thanks! This looks quite similar
to how it is in Rust, that you just lock/guard it and it is dropped at the end of
the current scope. I like that :)

> Regards,
> Markus

Best regards,
Jonas

On Sunday, 10 August 2025 10:49:02 CEST Markus Elfring wrote:
> …
> > +++ b/drivers/i2c/busses/i2c-rtl9300.c
> …
> > +static int mshv_vtl_sint_ioctl_set_eventfd(struct mshv_vtl_set_eventfd __user *arg)
> > +{
> …
> > @@ -244,7 +245,7 @@ static int rtl9300_i2c_smbus_xfer(struct i2c_adapter *adap, u16 addr, unsigned s
> >  
> >  	mutex_lock(&i2c->lock);
> >  	if (chan->sda_num != i2c->sda_num) {
> > -		ret = rtl9300_i2c_config_io(i2c, chan->sda_pin);
> > +		ret = rtl9300_i2c_config_io(i2c, chan);
> >  		if (ret)
> >  			goto out_unlock;
> …
> 
> Under which circumstances would you become interested to apply a statement
> like “guard(mutex)(&i2c->lock);”?
> https://elixir.bootlin.com/linux/v6.16/source/include/linux/mutex.h#L225

https://lwn.net/Articles/934679/ ("From cleanup functions to classes")

Kind regards,
	Sven