[PATCH] drm/tiny: Fix some error handling paths in sharp_memory_probe()

[Alex Lanzano]

On Sat, Oct 26, 2024 at 08:32:36AM +0200, Christophe JAILLET wrote:
> If an error occurs after allocating resources based on which
> "sharp,vcom-mode" is used, then these resources must be released, as
> already done in the .remove() function.
> 
> Use 2 new devm_add_action_or_reset() for that and simplify code
> accordingly.
> 
> Fixes: b8f9f21716fe ("drm/tiny: Add driver for Sharp Memory LCD")
> Signed-off-by: Christophe JAILLET <christophe.jaillet at wanadoo.fr>
> ---
> Compile tested only
> ---
>  drivers/gpu/drm/tiny/sharp-memory.c | 66 ++++++++++++++---------------
>  1 file changed, 32 insertions(+), 34 deletions(-)
> 
> diff --git a/drivers/gpu/drm/tiny/sharp-memory.c b/drivers/gpu/drm/tiny/sharp-memory.c
> index 2d2315bd6aef..01d1ce2462e1 100644
> --- a/drivers/gpu/drm/tiny/sharp-memory.c
> +++ b/drivers/gpu/drm/tiny/sharp-memory.c
> @@ -48,12 +48,6 @@ enum sharp_memory_model {
>  	LS044Q7DH01,
>  };
>  
> -enum sharp_memory_vcom_mode {
> -	SHARP_MEMORY_SOFTWARE_VCOM,
> -	SHARP_MEMORY_EXTERNAL_VCOM,
> -	SHARP_MEMORY_PWM_VCOM
> -};
> -
>  struct sharp_memory_device {
>  	struct drm_device drm;
>  	struct spi_device *spi;
> @@ -67,10 +61,6 @@ struct sharp_memory_device {
>  
>  	struct gpio_desc *enable_gpio;
>  
> -	struct task_struct *sw_vcom_signal;
> -	struct pwm_device *pwm_vcom_signal;
> -
> -	enum sharp_memory_vcom_mode vcom_mode;
>  	u8 vcom;
>  
>  	u32 pitch;
> @@ -500,25 +490,41 @@ static int sharp_memory_pipe_init(struct drm_device *dev,
>  	return drm_connector_attach_encoder(connector, encoder);
>  }
>  
> +static void sharp_memory_stop_kthread(void *data)
> +{
> +	struct task_struct *task = data;
> +
> +	kthread_stop(task);
> +}
> +
> +static void sharp_memory_disable_pwm(void *data)
> +{
> +	struct pwm_device *pwm = data;
> +
> +	pwm_disable(pwm);
> +}
> +
>  static int sharp_memory_init_pwm_vcom_signal(struct sharp_memory_device *smd)
>  {
>  	int ret;
>  	struct device *dev = &smd->spi->dev;
> +	struct pwm_device *pwm_vcom_signal;
>  	struct pwm_state pwm_state;
>  
> -	smd->pwm_vcom_signal = devm_pwm_get(dev, NULL);
> -	if (IS_ERR(smd->pwm_vcom_signal))
> -		return dev_err_probe(dev, PTR_ERR(smd->pwm_vcom_signal),
> +	pwm_vcom_signal = devm_pwm_get(dev, NULL);
> +	if (IS_ERR(pwm_vcom_signal))
> +		return dev_err_probe(dev, PTR_ERR(pwm_vcom_signal),
>  				     "Could not get pwm device\n");
>  
> -	pwm_init_state(smd->pwm_vcom_signal, &pwm_state);
> +	pwm_init_state(pwm_vcom_signal, &pwm_state);
>  	pwm_set_relative_duty_cycle(&pwm_state, 1, 10);
>  	pwm_state.enabled = true;
> -	ret = pwm_apply_might_sleep(smd->pwm_vcom_signal, &pwm_state);
> +	ret = pwm_apply_might_sleep(pwm_vcom_signal, &pwm_state);
>  	if (ret)
>  		return dev_err_probe(dev, -EINVAL, "Could not apply pwm state\n");
>  
> -	return 0;
> +	return devm_add_action_or_reset(dev, sharp_memory_disable_pwm,
> +					pwm_vcom_signal);
>  }
>  
>  static int sharp_memory_probe(struct spi_device *spi)
> @@ -595,15 +601,20 @@ static int sharp_memory_probe(struct spi_device *spi)
>  				     "Unable to find sharp,vcom-mode node in device tree\n");
>  
>  	if (!strcmp("software", vcom_mode_str)) {
> -		smd->vcom_mode = SHARP_MEMORY_SOFTWARE_VCOM;
> -		smd->sw_vcom_signal = kthread_run(sharp_memory_sw_vcom_signal_thread,
> -						  smd, "sw_vcom_signal");
> +		struct task_struct *sw_vcom_signal;
> +
> +		sw_vcom_signal = kthread_run(sharp_memory_sw_vcom_signal_thread,
> +					     smd, "sw_vcom_signal");
> +
> +		ret = devm_add_action_or_reset(dev, sharp_memory_stop_kthread,
> +					       sw_vcom_signal);
> +		if (ret)
> +			return ret;
>  
>  	} else if (!strcmp("external", vcom_mode_str)) {
> -		smd->vcom_mode = SHARP_MEMORY_EXTERNAL_VCOM;
> +		/* empty */
>  
>  	} else if (!strcmp("pwm", vcom_mode_str)) {
> -		smd->vcom_mode = SHARP_MEMORY_PWM_VCOM;
>  		ret = sharp_memory_init_pwm_vcom_signal(smd);
>  		if (ret)
>  			return ret;
> @@ -640,19 +651,6 @@ static void sharp_memory_remove(struct spi_device *spi)
>  
>  	drm_dev_unplug(&smd->drm);
>  	drm_atomic_helper_shutdown(&smd->drm);
> -
> -	switch (smd->vcom_mode) {
> -	case SHARP_MEMORY_SOFTWARE_VCOM:
> -		kthread_stop(smd->sw_vcom_signal);
> -		break;
> -
> -	case SHARP_MEMORY_EXTERNAL_VCOM:
> -		break;
> -
> -	case SHARP_MEMORY_PWM_VCOM:
> -		pwm_disable(smd->pwm_vcom_signal);
> -		break;
> -	}
>  }
>  
>  static struct spi_driver sharp_memory_spi_driver = {
> -- 
> 2.47.0
> 
Tested-by: Alex Lanzano <lanzano.alex at gmail.com>
Reviewed-by: Alex Lanzano <lanzano.alex at gmail.com>