Re: [PATCH] media: ov7670: Propagate clock enable failures

[Sakari Ailus]

Hi Pengpeng,

Thanks for the patch.

On Fri, Aug 28, 2026 at 05:15:06PM +0800, Pengpeng Hou wrote:
> ov7670_power_on() ignores clk_prepare_enable() and proceeds to toggle
> GPIOs and set info->on.  A failed clock enable can therefore be reported
> as a powered sensor and later be paired with an unbalanced clock
> disable.
> 
> Return the clock error before changing GPIO or software state, and
> propagate it from the subdevice power operation and probe.
> 
> The issue was identified via static analysis and manually reviewed.
> 
> Fixes: 030f9f682e66 ("media: ov7670: control clock along with power")
> 

Please remove extra newline here.

> Assisted-by: LLM

Which one?

> Signed-off-by: Pengpeng Hou <pengpeng@xxxxxxxxxxx>
> ---
>  drivers/media/i2c/ov7670.c | 20 +++++++++++++++-----
>  1 file changed, 15 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/media/i2c/ov7670.c b/drivers/media/i2c/ov7670.c
> index 4d040e9feeac..9c5bb391202d 100644
> --- a/drivers/media/i2c/ov7670.c
> +++ b/drivers/media/i2c/ov7670.c
> @@ -1647,14 +1647,17 @@ static int ov7670_s_register(struct v4l2_subdev *sd, const struct v4l2_dbg_regis
>  }
>  #endif
>  
> -static void ov7670_power_on(struct v4l2_subdev *sd)
> +static int ov7670_power_on(struct v4l2_subdev *sd)
>  {
>  	struct ov7670_info *info = to_state(sd);
> +	int ret;
>  
>  	if (info->on)

That's also unnecessary. No need to change this for a bugfix though.

It'd be also nice to convert the driver to use Runtime PM but that is
obviously out of scope of this patch.

> -		return;
> +		return 0;
>  
> -	clk_prepare_enable(info->clk);
> +	ret = clk_prepare_enable(info->clk);
> +	if (ret)
> +		return ret;
>  
>  	if (info->pwdn_gpio)
>  		gpiod_set_value(info->pwdn_gpio, 0);
> @@ -1667,6 +1670,8 @@ static void ov7670_power_on(struct v4l2_subdev *sd)
>  		usleep_range(3000, 5000);
>  
>  	info->on = true;
> +
> +	return 0;
>  }
>  
>  static void ov7670_power_off(struct v4l2_subdev *sd)
> @@ -1687,12 +1692,15 @@ static void ov7670_power_off(struct v4l2_subdev *sd)
>  static int ov7670_s_power(struct v4l2_subdev *sd, int on)
>  {
>  	struct ov7670_info *info = to_state(sd);
> +	int ret;
>  
>  	if (info->on == on)
>  		return 0;
>  
>  	if (on) {
> -		ov7670_power_on(sd);

You can also declare ret here.

> +		ret = ov7670_power_on(sd);
> +		if (ret)
> +			return ret;
>  		ov7670_init(sd, 0);
>  		ov7670_apply_fmt(sd);
>  		ov7675_apply_framerate(sd);
> @@ -1872,7 +1880,9 @@ static int ov7670_probe(struct i2c_client *client)
>  	if (ret)
>  		return ret;
>  
> -	ov7670_power_on(sd);
> +	ret = ov7670_power_on(sd);
> +	if (ret)
> +		return ret;
>  
>  	if (info->clk) {
>  		info->clock_speed = clk_get_rate(info->clk) / 1000000;

-- 
Regards,

Sakari Ailus