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SubjectRe: [PATCH] media: i2c: dw9714: Register a callback to disable the regulator
Hi Zheyu,

Thanks for the patch.

On Sat, Apr 09, 2022 at 10:09:39PM +0800, Zheyu Ma wrote:
> When the driver fails to probe, we will get the following splat:
>
> [ 59.305988] ------------[ cut here ]------------
> [ 59.306417] WARNING: CPU: 2 PID: 395 at drivers/regulator/core.c:2257 _regulator_put+0x3ec/0x4e0
> [ 59.310345] RIP: 0010:_regulator_put+0x3ec/0x4e0
> [ 59.318362] Call Trace:
> [ 59.318582] <TASK>
> [ 59.318765] regulator_put+0x1f/0x30
> [ 59.319058] devres_release_group+0x319/0x3d0
> [ 59.319420] i2c_device_probe+0x766/0x940
>
> Fix this by adding a callback that will deal with the disabling when the
> driver fails to probe.
>
> Signed-off-by: Zheyu Ma <zheyuma97@gmail.com>
> ---
> drivers/media/i2c/dw9714.c | 11 +++++++++++
> 1 file changed, 11 insertions(+)
>
> diff --git a/drivers/media/i2c/dw9714.c b/drivers/media/i2c/dw9714.c
> index cd7008ad8f2f..eccd05fc50c7 100644
> --- a/drivers/media/i2c/dw9714.c
> +++ b/drivers/media/i2c/dw9714.c
> @@ -137,6 +137,13 @@ static int dw9714_init_controls(struct dw9714_device *dev_vcm)
> return hdl->error;
> }
>
> +static void dw9714_disable_regulator(void *arg)
> +{
> + struct dw9714_device *dw9714_dev = arg;
> +
> + regulator_disable(dw9714_dev->vcc);
> +}
> +
> static int dw9714_probe(struct i2c_client *client)
> {
> struct dw9714_device *dw9714_dev;
> @@ -157,6 +164,10 @@ static int dw9714_probe(struct i2c_client *client)
> return rval;
> }
>
> + rval = devm_add_action_or_reset(&client->dev, dw9714_disable_regulator, dw9714_dev);
> + if (rval)
> + return rval;
> +
> v4l2_i2c_subdev_init(&dw9714_dev->sd, client, &dw9714_ops);
> dw9714_dev->sd.flags |= V4L2_SUBDEV_FL_HAS_DEVNODE |
> V4L2_SUBDEV_FL_HAS_EVENTS;

Could you instead disable the regulator in error handling in the probe
function?

--
Sakari Ailus

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