Re: [PATCH 2/4] media: i2c: Add driver for Sony IMX728

Sebastian LaVine
2025-02-26T20:13:36Z

On Wed Feb 12, 2025 at 3:11 PM EST, Krzysztof Kozlowski wrote:
> On 12/02/2025 20:56, Sebastian LaVine wrote:
>>
>> ...
>>
>> +static int imx728_reset(struct imx728 *imx728)
>> +{
>> +
>> + int ret = 0;
>> +
>> + // Prefer hardware reset if available.
>> + if (!IS_ERR_OR_NULL(imx728->reset_gpio)) {
>
> Here can be ERR (although why?) but...
>
>> + gpiod_set_value_cansleep(imx728->reset_gpio, 1);
>>
>> ...
>>
>> +static int imx728_power_off(struct imx728 *imx728)
>> +{
>> +
>> + if (imx728->reset_gpio) {
>
> Here cannot.
>
>> + gpiod_set_value_cansleep(imx728->reset_gpio, 1);
>> +
>> + usleep_range(1, 10);
>> + }
>> + clk_disable_unprepare(imx728->clk);
>> + return 0;
>> +}
>> +
>>
>> ...
>>
>> +static int imx728_probe(struct i2c_client *client)
>> +{
>> + struct imx728 *imx728;
>> + struct v4l2_subdev *sd;
>> + struct v4l2_ctrl_handler *ctrl_hdr;
>> + int ret;
>> +
>> + imx728 = devm_kzalloc(&client->dev, sizeof(*imx728), GFP_KERNEL);
>> + if (!imx728)
>> + return -ENOMEM;
>> +
>> + imx728->dev = &client->dev;
>> +
>> + imx728->regmap = devm_cci_regmap_init_i2c(client, 16);
>> + if (IS_ERR(imx728->regmap))
>> + return PTR_ERR(imx728->regmap);
>> +
>> + imx728->reset_gpio = devm_gpiod_get_optional(imx728->dev,
>> + "reset", GPIOD_OUT_LOW);
>> + if (IS_ERR(imx728->reset_gpio))
>> + return PTR_ERR(imx728->reset_gpio);
>
> So can it be ERR after that point? Looks like not.
>

I see what you mean -- I'll change the check in imx728_reset to a simple
null check in v4. Thanks.

> (Jumping back up to previous inline feedback)
>
> ...
>
>> +
>> +static int imx728_set_stream(struct v4l2_subdev *sd, int enable)
>> +{
>> + struct imx728 *imx728 = to_imx728(sd);
>> + int ret;
>> +
>> + mutex_lock(&imx728->lock);
>
> Just use guard. That's actually perfect candidate.
>

Okay -- I'll include this change in v4. I'm not so familiar with using
this interface, so please let me know if this is incorrect:

diff --git a/drivers/media/i2c/imx728.c b/drivers/media/i2c/imx728.c
index 4a6dfa0a6c58..d7d62e9917a4 100644
--- a/drivers/media/i2c/imx728.c
+++ b/drivers/media/i2c/imx728.c
@@ -9320,17 +9320,16 @@ static int imx728_set_stream(struct v4l2_subdev *sd, int enable)
struct imx728 *imx728 = to_imx728(sd);
int ret;

- mutex_lock(&imx728->lock);
+ guard(mutex)(&imx728->lock);
+
- if (imx728->streaming == enable) {
+ if (imx728->streaming == enable)
- mutex_unlock(&imx728->lock);
return 0;
- }

if (enable) {
ret = pm_runtime_get_sync(imx728->dev);
if (ret < 0) {
pm_runtime_put_noidle(imx728->dev);
- goto err_unlock;
+ goto err;
}

ret = imx728_start_stream(imx728);
@@ -9349,15 +9348,12 @@ static int imx728_set_stream(struct v4l2_subdev *sd, int enable)
__v4l2_ctrl_grab(imx728->ctrl.h_flip, enable);
__v4l2_ctrl_grab(imx728->ctrl.v_flip, enable);

- mutex_unlock(&imx728->lock);
-
return 0;

err_runtime_put:
pm_runtime_put(imx728->dev);

-err_unlock:
- mutex_unlock(&imx728->lock);
+err:
dev_err(imx728->dev,
"%s: failed to setup streaming %d\n", __func__, ret);
return ret;

Thanks,

--
Sebastian