Re: [PATCH RFC leds + net-next 1/3] leds: trigger: add support for LED-private device triggers

[Jacek Anaszewski <jacek.anaszewski@gmail.com>]

Hi Marek,

On 7/16/20 7:17 PM, Marek Behún wrote:
> Some LED controllers may come with an internal HW triggering mechanism
> for the LED and the ability to switch between SW control and the
> internal HW control. This includes most PHYs, various ethernet switches,
> the Turris Omnia LED controller or AXP20X PMIC.
> 
> This adds support for registering such triggers.
> 
> This code is based on work by Pavel Machek <pavel@ucw.cz> and
> Ondřej Jirman <megous@megous.com>.
> 
> Signed-off-by: Marek Behún <marek.behun@nic.cz>
> ---
>   drivers/leds/led-triggers.c | 26 ++++++++++++++++++++------
>   include/linux/leds.h        | 10 ++++++++++
>   2 files changed, 30 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/leds/led-triggers.c b/drivers/leds/led-triggers.c
> index 79e30d2cb7a5..81e758d5a048 100644
> --- a/drivers/leds/led-triggers.c
> +++ b/drivers/leds/led-triggers.c
> @@ -27,6 +27,12 @@ LIST_HEAD(trigger_list);
>   
>    /* Used by LED Class */
>   
> +static inline bool
> +trigger_relevant(struct led_classdev *led_cdev, struct led_trigger *trig)
> +{
> +	return !trig->trigger_type || trig->trigger_type == led_cdev->trigger_type;
> +}
> +
>   ssize_t led_trigger_write(struct file *filp, struct kobject *kobj,
>   			  struct bin_attribute *bin_attr, char *buf,
>   			  loff_t pos, size_t count)
> @@ -50,7 +56,7 @@ ssize_t led_trigger_write(struct file *filp, struct kobject *kobj,
>   
>   	down_read(&triggers_list_lock);
>   	list_for_each_entry(trig, &trigger_list, next_trig) {
> -		if (sysfs_streq(buf, trig->name)) {
> +		if (sysfs_streq(buf, trig->name) && trigger_relevant(led_cdev, trig)) {
>   			down_write(&led_cdev->trigger_lock);
>   			led_trigger_set(led_cdev, trig);
>   			up_write(&led_cdev->trigger_lock);
> @@ -93,8 +99,12 @@ static int led_trigger_format(char *buf, size_t size,
>   				       led_cdev->trigger ? "none" : "[none]");
>   
>   	list_for_each_entry(trig, &trigger_list, next_trig) {
> -		bool hit = led_cdev->trigger &&
> -			!strcmp(led_cdev->trigger->name, trig->name);
> +		bool hit;
> +
> +		if (!trigger_relevant(led_cdev, trig))
> +			continue;
> +
> +		hit = led_cdev->trigger && !strcmp(led_cdev->trigger->name, trig->name);
>   
>   		len += led_trigger_snprintf(buf + len, size - len,
>   					    " %s%s%s", hit ? "[" : "",
> @@ -243,7 +253,8 @@ void led_trigger_set_default(struct led_classdev *led_cdev)
>   	down_read(&triggers_list_lock);
>   	down_write(&led_cdev->trigger_lock);
>   	list_for_each_entry(trig, &trigger_list, next_trig) {
> -		if (!strcmp(led_cdev->default_trigger, trig->name)) {
> +		if (!strcmp(led_cdev->default_trigger, trig->name) &&
> +		    trigger_relevant(led_cdev, trig)) {
>   			led_cdev->flags |= LED_INIT_DEFAULT_TRIGGER;
>   			led_trigger_set(led_cdev, trig);
>   			break;
> @@ -280,7 +291,9 @@ int led_trigger_register(struct led_trigger *trig)
>   	down_write(&triggers_list_lock);
>   	/* Make sure the trigger's name isn't already in use */
>   	list_for_each_entry(_trig, &trigger_list, next_trig) {
> -		if (!strcmp(_trig->name, trig->name)) {
> +		if (!strcmp(_trig->name, trig->name) &&
> +		    (trig->trigger_type == _trig->trigger_type ||
> +		     !trig->trigger_type || !_trig->trigger_type)) {
>   			up_write(&triggers_list_lock);
>   			return -EEXIST;
>   		}
> @@ -294,7 +307,8 @@ int led_trigger_register(struct led_trigger *trig)
>   	list_for_each_entry(led_cdev, &leds_list, node) {
>   		down_write(&led_cdev->trigger_lock);
>   		if (!led_cdev->trigger && led_cdev->default_trigger &&
> -			    !strcmp(led_cdev->default_trigger, trig->name)) {
> +		    !strcmp(led_cdev->default_trigger, trig->name) &&
> +		    trigger_relevant(led_cdev, trig)) {
>   			led_cdev->flags |= LED_INIT_DEFAULT_TRIGGER;
>   			led_trigger_set(led_cdev, trig);
>   		}
> diff --git a/include/linux/leds.h b/include/linux/leds.h
> index 2451962d1ec5..6a8d6409c993 100644
> --- a/include/linux/leds.h
> +++ b/include/linux/leds.h
> @@ -57,6 +57,10 @@ struct led_init_data {
>   	bool devname_mandatory;
>   };
>   
> +struct led_hw_trigger_type {
> +	int dummy;
> +};
> +
>   struct led_classdev {
>   	const char		*name;
>   	enum led_brightness	 brightness;
> @@ -141,6 +145,9 @@ struct led_classdev {
>   	void			*trigger_data;
>   	/* true if activated - deactivate routine uses it to do cleanup */
>   	bool			activated;
> +
> +	/* LEDs that have private triggers have this set */
> +	struct led_hw_trigger_type	*trigger_type;
>   #endif
>   
>   #ifdef CONFIG_LEDS_BRIGHTNESS_HW_CHANGED
> @@ -345,6 +352,9 @@ struct led_trigger {
>   	int		(*activate)(struct led_classdev *led_cdev);
>   	void		(*deactivate)(struct led_classdev *led_cdev);
>   
> +	/* LED-private triggers have this set */
> +	struct led_hw_trigger_type *trigger_type;
> +
>   	/* LEDs under control by this trigger (for simple triggers) */
>   	rwlock_t	  leddev_list_lock;
>   	struct list_head  led_cdevs;

Looks good to me:

Acked-by: Jacek Anaszewski <jacek.anaszewski@gmail.com>

-- 
Best regards,
Jacek Anaszewski