Hi Ondrej,

On Tue, Jul 14, 2020 at 12:23:01PM +0200, Ondrej Jirman wrote:
> Make enable-gpio optional to allow using this driver with boards that
> have vibrator connected to a power supply without intermediate gpio
> based enable circuitry.
> 
> Also avoid a case where neither regulator nor enable gpio is specified,
> and bail out in probe in such a case.
> 
> Signed-off-by: Ondrej Jirman <meg...@megous.com>
> ---
>  drivers/input/misc/gpio-vibra.c | 14 ++++++++++----
>  1 file changed, 10 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/input/misc/gpio-vibra.c b/drivers/input/misc/gpio-vibra.c
> index f79f75595dd7..b3bb7e61ed1d 100644
> --- a/drivers/input/misc/gpio-vibra.c
> +++ b/drivers/input/misc/gpio-vibra.c
> @@ -39,7 +39,7 @@ static int gpio_vibrator_start(struct gpio_vibrator 
> *vibrator)
>       struct device *pdev = vibrator->input->dev.parent;
>       int err;
>  
> -     if (!vibrator->vcc_on) {
> +     if (vibrator->vcc && !vibrator->vcc_on) {
>               err = regulator_enable(vibrator->vcc);
>               if (err) {
>                       dev_err(pdev, "failed to enable regulator: %d\n", err);
> @@ -57,7 +57,7 @@ static void gpio_vibrator_stop(struct gpio_vibrator 
> *vibrator)
>  {
>       gpiod_set_value_cansleep(vibrator->gpio, 0);
>  
> -     if (vibrator->vcc_on) {
> +     if (vibrator->vcc && vibrator->vcc_on) {
>               regulator_disable(vibrator->vcc);
>               vibrator->vcc_on = false;
>       }
> @@ -112,7 +112,7 @@ static int gpio_vibrator_probe(struct platform_device 
> *pdev)
>       if (!vibrator->input)
>               return -ENOMEM;
>  
> -     vibrator->vcc = devm_regulator_get(&pdev->dev, "vcc");
> +     vibrator->vcc = devm_regulator_get_optional(&pdev->dev, "vcc");

I know it is very surprising, but regulator_get_optional does not return
NULL when regulator is not present, but rather ERR_PTR(-ENODEV). You
need to replace it with NULL in the branch below, or change conditions
to !IS_ERR(virbrator->vcc) (and still handle -ENODEV in the branch
below).

>       err = PTR_ERR_OR_ZERO(vibrator->vcc);
>       if (err) {
>               if (err != -EPROBE_DEFER)
> @@ -121,7 +121,8 @@ static int gpio_vibrator_probe(struct platform_device 
> *pdev)
>               return err;
>       }
>  
> -     vibrator->gpio = devm_gpiod_get(&pdev->dev, "enable", GPIOD_OUT_LOW);
> +     vibrator->gpio = devm_gpiod_get_optional(&pdev->dev, "enable",
> +                                              GPIOD_OUT_LOW);
>       err = PTR_ERR_OR_ZERO(vibrator->gpio);
>       if (err) {
>               if (err != -EPROBE_DEFER)
> @@ -130,6 +131,11 @@ static int gpio_vibrator_probe(struct platform_device 
> *pdev)
>               return err;
>       }
>  
> +     if (!vibrator->vcc && !vibrator->gpio) {
> +             dev_err(&pdev->dev, "Neither gpio nor regulator provided\n");
> +             return -EINVAL;
> +     }
> +
>       INIT_WORK(&vibrator->play_work, gpio_vibrator_play_work);
>  
>       vibrator->input->name = "gpio-vibrator";
> -- 
> 2.27.0
> 

Thanks.

-- 
Dmitry

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