On Sat, Apr 29, 2023 at 12:45:32PM +0200, Artur Weber wrote:
> Also deprecate the pwm-period DT property, as it is now redundant
> (pwms property already contains period value).
> 
> Signed-off-by: Artur Weber <aweber.ker...@gmail.com>
> ---
>  drivers/video/backlight/lp855x_bl.c | 48 ++++++++++++++++-------------
>  1 file changed, 26 insertions(+), 22 deletions(-)
> 
> diff --git a/drivers/video/backlight/lp855x_bl.c 
> b/drivers/video/backlight/lp855x_bl.c
> index 81012bf29baf..21eb4943ed56 100644
> --- a/drivers/video/backlight/lp855x_bl.c
> +++ b/drivers/video/backlight/lp855x_bl.c
> @@ -218,23 +218,10 @@ static int lp855x_configure(struct lp855x *lp)
>  
>  static void lp855x_pwm_ctrl(struct lp855x *lp, int br, int max_br)
>  {
> -     struct pwm_device *pwm;
>       struct pwm_state state;
>  
> -     /* request pwm device with the consumer name */
> -     if (!lp->pwm) {
> -             pwm = devm_pwm_get(lp->dev, lp->chipname);
> -             if (IS_ERR(pwm))
> -                     return;
> -
> -             lp->pwm = pwm;
> -
> -             pwm_init_state(lp->pwm, &state);
> -     } else {
> -             pwm_get_state(lp->pwm, &state);
> -     }
> +     pwm_get_state(lp->pwm, &state);

pwm_get_state returns an error code. Do you care if it fails? (You
probably should.)
>  
> -     state.period = lp->pdata->period_ns;
>       state.duty_cycle = div_u64(br * state.period, max_br);
>       state.enabled = state.duty_cycle;
>  
> @@ -339,6 +326,7 @@ static int lp855x_parse_dt(struct lp855x *lp)
>       of_property_read_string(node, "bl-name", &pdata->name);
>       of_property_read_u8(node, "dev-ctrl", &pdata->device_control);
>       of_property_read_u8(node, "init-brt", &pdata->initial_brightness);
> +     /* Deprecated, specify period in pwms property instead */
>       of_property_read_u32(node, "pwm-period", &pdata->period_ns);
>  
>       /* Fill ROM platform data if defined */
> @@ -399,6 +387,7 @@ static int lp855x_probe(struct i2c_client *cl)
>       const struct i2c_device_id *id = i2c_client_get_device_id(cl);
>       const struct acpi_device_id *acpi_id = NULL;
>       struct device *dev = &cl->dev;
> +     struct pwm_state pwmstate;
>       struct lp855x *lp;
>       int ret;
>  
> @@ -457,11 +446,6 @@ static int lp855x_probe(struct i2c_client *cl)
>               }
>       }
>  
> -     if (lp->pdata->period_ns > 0)
> -             lp->mode = PWM_BASED;
> -     else
> -             lp->mode = REGISTER_BASED;
> -
>       lp->supply = devm_regulator_get(dev, "power");
>       if (IS_ERR(lp->supply)) {
>               if (PTR_ERR(lp->supply) == -EPROBE_DEFER)
> @@ -472,11 +456,31 @@ static int lp855x_probe(struct i2c_client *cl)
>       lp->enable = devm_regulator_get_optional(dev, "enable");
>       if (IS_ERR(lp->enable)) {
>               ret = PTR_ERR(lp->enable);
> -             if (ret == -ENODEV) {
> +             if (ret == -ENODEV)
>                       lp->enable = NULL;
> -             } else {
> +             else
>                       return dev_err_probe(dev, ret, "getting enable 
> regulator\n");
> -             }
> +     }
> +
> +     lp->pwm = devm_pwm_get(lp->dev, lp->chipname);
> +     if (IS_ERR(lp->pwm)) {
> +             ret = PTR_ERR(lp->pwm);
> +             if (ret == -ENODEV || ret == -EINVAL)

Why would you ignore EINVAL?

> +                     lp->pwm = NULL;
> +             else
> +                     return dev_err_probe(dev, ret, "getting PWM\n");
> +
> +             lp->mode = REGISTER_BASED;
> +             dev_dbg(dev, "mode: register based\n");
> +     } else {

pwmstate could be declared here.

> +             pwm_init_state(lp->pwm, &pwmstate);
> +             /* Legacy platform data compatibility */
> +             if (lp->pdata->period_ns > 0)
> +                     pwmstate.period = lp->pdata->period_ns;
> +             pwm_apply_state(lp->pwm, &pwmstate);

This is a change in behaviour. Before lp855x_probe() didn't modify the
state the bootloader left the backlight in. Now you're disabling it (I
think). Is this intended?

Best regards
Uwe

-- 
Pengutronix e.K.                           | Uwe Kleine-König            |
Industrial Linux Solutions                 | https://www.pengutronix.de/ |

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