Re: [PATCH 3/8] iio: trigger: stm32-lptimer: add support for stm32mp25

[Jonathan Cameron <jic23@kernel.org>]

On Mon, 24 Feb 2025 19:01:45 +0100
Fabrice Gasnier <fabrice.gasnier@foss.st.com> wrote:

> From: Olivier Moysan <olivier.moysan@foss.st.com>
> 
> Add support for STM32MP25 SoC. Use newly introduced compatible to handle
> this new HW variant. Add new trigger definitions that can be used by the
> stm32 analog-to-digital converter. Use compatible data to identify them.
> 
> Signed-off-by: Olivier Moysan <olivier.moysan@foss.st.com>
> Signed-off-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com>

Hi. I'm not really following why you can't use devm calls for the
trigger probe path and hence why you need the explicit remove.
Feels like a lot of infrastructure and I can't see why we need it.

Jonathan


> @@ -54,25 +82,49 @@ bool is_stm32_lptim_trigger(struct iio_trigger *trig)
>  }
>  EXPORT_SYMBOL(is_stm32_lptim_trigger);
>  
> -static int stm32_lptim_setup_trig(struct stm32_lptim_trigger *priv)
> +static void stm32_lptim_unregister_triggers(struct stm32_lptim_trigger *priv)
>  {
> -	struct iio_trigger *trig;
> +	struct iio_trigger *tr;
>  
> -	trig = devm_iio_trigger_alloc(priv->dev, "%s", priv->trg);
> -	if  (!trig)
> -		return -ENOMEM;
> +	list_for_each_entry(tr, &priv->tr_list, alloc_list)
> +		iio_trigger_unregister(tr);
> +}
> +
> +static int stm32_lptim_register_triggers(struct stm32_lptim_trigger *priv)
> +{
> +	const char * const *cur = priv->triggers;
> +	int ret;
>  
> -	trig->dev.parent = priv->dev->parent;
> -	trig->ops = &stm32_lptim_trigger_ops;
> -	iio_trigger_set_drvdata(trig, priv);
> +	INIT_LIST_HEAD(&priv->tr_list);
>  
> -	return devm_iio_trigger_register(priv->dev, trig);
> +	while (cur && *cur) {
> +		struct iio_trigger *trig;
> +
> +		trig = devm_iio_trigger_alloc(priv->dev, "%s", *cur);
> +		if  (!trig)
> +			return -ENOMEM;
> +
> +		trig->dev.parent = priv->dev->parent;
> +		trig->ops = &stm32_lptim_trigger_ops;
> +		iio_trigger_set_drvdata(trig, priv);
> +
> +		ret = iio_trigger_register(trig);

I'm not really following why you can't use devm_iio_trigger_register() here
and avoid your own tracking with the list below.


> +		if (ret)
> +			return ret;
> +
> +		list_add_tail(&trig->alloc_list, &priv->tr_list);
> +		cur++;
> +	}
> +
> +	return 0;
>  }
>  
>  static int stm32_lptim_trigger_probe(struct platform_device *pdev)
>  {
>  	struct stm32_lptim_trigger *priv;
> +	struct stm32_lptim_cfg const *lptim_cfg;
>  	u32 index;
> +	int ret;
>  
>  	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
>  	if (!priv)
> @@ -81,23 +133,42 @@ static int stm32_lptim_trigger_probe(struct platform_device *pdev)
>  	if (device_property_read_u32(&pdev->dev, "reg", &index))
>  		return -EINVAL;
>  
> -	if (index >= ARRAY_SIZE(stm32_lptim_triggers))
> +	lptim_cfg = device_get_match_data(&pdev->dev);
> +
> +	if (index >= lptim_cfg->nb_triggers)
>  		return -EINVAL;
>  
>  	priv->dev = &pdev->dev;
> -	priv->trg = stm32_lptim_triggers[index];
> +	priv->triggers = lptim_cfg->triggers[index];
> +
> +	ret = stm32_lptim_register_triggers(priv);
> +	if (ret) {
> +		stm32_lptim_unregister_triggers(priv);
> +		return ret;
> +	}
> +
> +	platform_set_drvdata(pdev, priv);
> +
> +	return 0;
> +}
> +
> +static void stm32_lptim_trigger_remove(struct platform_device *pdev)
> +{
> +	struct stm32_lptim_trigger *priv = platform_get_drvdata(pdev);
>  
> -	return stm32_lptim_setup_trig(priv);
> +	stm32_lptim_unregister_triggers(priv);

Why not a devm_add_action_or_reset?
or for that matter a devm_iio_trigger_register() in the first place.

>  }
>  
>  static const struct of_device_id stm32_lptim_trig_of_match[] = {
> -	{ .compatible = "st,stm32-lptimer-trigger", },
> +	{ .compatible = "st,stm32-lptimer-trigger", .data = (void *)&stm32mp15_lptim_cfg },
> +	{ .compatible = "st,stm32mp25-lptimer-trigger", .data = (void *)&stm32mp25_lptim_cfg},
Why cast away a const then pass it to a const void *?

That is I don't think the casts are needed.

>  	{},
>  };
>  MODULE_DEVICE_TABLE(of, stm32_lptim_trig_of_match);
>  
>  static struct platform_driver stm32_lptim_trigger_driver = {
>  	.probe = stm32_lptim_trigger_probe,
> +	.remove = stm32_lptim_trigger_remove,
>  	.driver = {
>  		.name = "stm32-lptimer-trigger",
>  		.of_match_table = stm32_lptim_trig_of_match,
> diff --git a/include/linux/iio/timer/stm32-lptim-trigger.h b/include/linux/iio/timer/stm32-lptim-trigger.h
> index a34dcf6a6001..ce3cf0addb2e 100644
> --- a/include/linux/iio/timer/stm32-lptim-trigger.h
> +++ b/include/linux/iio/timer/stm32-lptim-trigger.h
> @@ -14,6 +14,15 @@
>  #define LPTIM1_OUT	"lptim1_out"
>  #define LPTIM2_OUT	"lptim2_out"
>  #define LPTIM3_OUT	"lptim3_out"
> +#define LPTIM4_OUT	"lptim4_out"
> +#define LPTIM5_OUT	"lptim5_out"
> +
> +#define LPTIM1_CH1	"lptim1_ch1"
> +#define LPTIM1_CH2	"lptim1_ch2"
> +#define LPTIM2_CH1	"lptim2_ch1"
> +#define LPTIM2_CH2	"lptim2_ch2"
> +#define LPTIM3_CH1	"lptim3_ch1"
> +#define LPTIM4_CH1	"lptim4_ch1"
>  
>  #if IS_REACHABLE(CONFIG_IIO_STM32_LPTIMER_TRIGGER)
>  bool is_stm32_lptim_trigger(struct iio_trigger *trig);