Messages in this thread | | | Subject | Re: [PATCH 1/2] leds: Add control of the voltage/current regulator to the LED core | From | Jean-Jacques Hiblot <> | Date | Mon, 15 Jul 2019 11:47:08 +0200 |
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On 15/07/2019 11:24, Daniel Thompson wrote: > On Mon, Jul 15, 2019 at 11:01:29AM +0200, Jean-Jacques Hiblot wrote: >> Hi Dan, >> >> On 12/07/2019 20:49, Dan Murphy wrote: >>> JJ >>> >>> On 7/8/19 5:35 AM, Jean-Jacques Hiblot wrote: >>>> A LED is usually powered by a voltage/current regulator. Let the LED >>>> core >>> Let the LED core know >>>> about it. This allows the LED core to turn on or off the power supply >>>> as needed. >>>> Signed-off-by: Jean-Jacques Hiblot <jjhiblot@ti.com> >>>> --- >>>> drivers/leds/led-class.c | 10 ++++++++ >>>> drivers/leds/led-core.c | 53 +++++++++++++++++++++++++++++++++++++--- >>>> include/linux/leds.h | 4 +++ >>>> 3 files changed, 64 insertions(+), 3 deletions(-) >>>> >>>> diff --git a/drivers/leds/led-class.c b/drivers/leds/led-class.c >>>> index 4793e77808e2..e01b2d982564 100644 >>>> --- a/drivers/leds/led-class.c >>>> +++ b/drivers/leds/led-class.c >>>> @@ -17,6 +17,7 @@ >>>> #include <linux/slab.h> >>>> #include <linux/spinlock.h> >>>> #include <linux/timer.h> >>>> +#include <linux/regulator/consumer.h> >>> What if you move this to leds.h so core and class can both include it. >>> >>> >>>> #include <uapi/linux/uleds.h> >>>> #include "leds.h" >>>> @@ -272,6 +273,15 @@ int of_led_classdev_register(struct device >>>> *parent, struct device_node *np, >>>> dev_warn(parent, "Led %s renamed to %s due to name collision", >>>> led_cdev->name, dev_name(led_cdev->dev)); >>>> + led_cdev->regulator = devm_regulator_get(led_cdev->dev, "power"); >>> Is the regulator always going to be called power? >> Actually in the dts, that will be "power-supply". I lacked the imagination >> to come up with a better name. >> >> >> >>>> + if (IS_ERR(led_cdev->regulator)) { >>>> + dev_err(led_cdev->dev, "Cannot get the power supply for %s\n", >>>> + led_cdev->name); >>>> + device_unregister(led_cdev->dev); >>>> + mutex_unlock(&led_cdev->led_access); >>>> + return PTR_ERR(led_cdev->regulator); >>> This is listed as optional in the DT doc. This appears to be required. >> The regulator core will provide a dummy regulator if none is given in the >> device tree. I would rather have an error in that case, but that is not how >> it works. > If you actively wanted to get -ENODEV back when there is no regulator > then you can use devm_regulator_get_optional() for that. > > However perhaps be careful what you wish for. If you use get_optional() > then you will have to sprinkle NULL or IS_ERR() checks everywhere. I'd > favour using the current approach!
Thanks for the info. I think I'll use the get_optionnal(). That will add a bit of complexity, but it will avoid deferring some work in led_set_brightness_nopm() when it is not needed.
JJ
> > > Daniel. > >> >>> I prefer to keep it optional. Many LED drivers are connected to fixed >>> non-managed supplies. >>> >>>> + } >>>> + >>>> if (led_cdev->flags & LED_BRIGHT_HW_CHANGED) { >>>> ret = led_add_brightness_hw_changed(led_cdev); >>>> if (ret) { >>>> diff --git a/drivers/leds/led-core.c b/drivers/leds/led-core.c >>>> index 7107cd7e87cf..139de6b08cad 100644 >>>> --- a/drivers/leds/led-core.c >>>> +++ b/drivers/leds/led-core.c >>>> @@ -16,6 +16,7 @@ >>>> #include <linux/rwsem.h> >>>> #include <linux/slab.h> >>>> #include "leds.h" >>>> +#include <linux/regulator/consumer.h> >>>> DECLARE_RWSEM(leds_list_lock); >>>> EXPORT_SYMBOL_GPL(leds_list_lock); >>>> @@ -23,6 +24,31 @@ EXPORT_SYMBOL_GPL(leds_list_lock); >>>> LIST_HEAD(leds_list); >>>> EXPORT_SYMBOL_GPL(leds_list); >>>> +static bool __led_need_regulator_update(struct led_classdev >>>> *led_cdev, >>>> + int brightness) >>>> +{ >>>> + bool new_regulator_state = (brightness != LED_OFF); >>>> + >>>> + return led_cdev->regulator_state != new_regulator_state; >>>> +} >>>> + >>>> +static int __led_handle_regulator(struct led_classdev *led_cdev, >>>> + int brightness) >>>> +{ >>>> + if (__led_need_regulator_update(led_cdev, brightness)) { >>>> + int ret; >>> Prefer to this to be moved up. >> ok >>>> + >>>> + if (brightness != LED_OFF) >>>> + ret = regulator_enable(led_cdev->regulator); >>>> + else >>>> + ret = regulator_disable(led_cdev->regulator); >>>> + if (ret) >>>> + return ret; >>> new line >>>> + led_cdev->regulator_state = (brightness != LED_OFF); >>>> + } >>>> + return 0; >>>> +} >>>> + >>>> static int __led_set_brightness(struct led_classdev *led_cdev, >>>> enum led_brightness value) >>>> { >>>> @@ -80,6 +106,7 @@ static void led_timer_function(struct timer_list *t) >>>> } >>>> led_set_brightness_nosleep(led_cdev, brightness); >>>> + __led_handle_regulator(led_cdev, brightness); >>> Again this seems to indicate that the regulator is a required property >>> for the LEDs >>> >>> This needs to be made optional. And the same comment through out for >>> every call. >>> >>> >>>> /* Return in next iteration if led is in one-shot mode and >>>> we are in >>>> * the final blink state so that the led is toggled each >>>> delay_on + >>>> @@ -115,6 +142,8 @@ static void set_brightness_delayed(struct >>>> work_struct *ws) >>>> if (ret == -ENOTSUPP) >>>> ret = __led_set_brightness_blocking(led_cdev, >>>> led_cdev->delayed_set_value); >>>> + __led_handle_regulator(led_cdev, led_cdev->delayed_set_value); >>>> + >>>> if (ret < 0 && >>>> /* LED HW might have been unplugged, therefore don't warn */ >>>> !(ret == -ENODEV && (led_cdev->flags & LED_UNREGISTERING) && >>>> @@ -141,6 +170,7 @@ static void led_set_software_blink(struct >>>> led_classdev *led_cdev, >>>> /* never on - just set to off */ >>>> if (!delay_on) { >>>> led_set_brightness_nosleep(led_cdev, LED_OFF); >>>> + __led_handle_regulator(led_cdev, LED_OFF); >>>> return; >>>> } >>>> @@ -148,6 +178,7 @@ static void led_set_software_blink(struct >>>> led_classdev *led_cdev, >>>> if (!delay_off) { >>>> led_set_brightness_nosleep(led_cdev, >>>> led_cdev->blink_brightness); >>>> + __led_handle_regulator(led_cdev, led_cdev->blink_brightness); >>>> return; >>>> } >>>> @@ -256,8 +287,14 @@ void led_set_brightness_nopm(struct >>>> led_classdev *led_cdev, >>>> enum led_brightness value) >>>> { >>>> /* Use brightness_set op if available, it is guaranteed not to >>>> sleep */ >>>> - if (!__led_set_brightness(led_cdev, value)) >>>> - return; >>>> + if (!__led_set_brightness(led_cdev, value)) { >>>> + /* >>>> + * if regulator state doesn't need to be changed, that is all/ >>>> + * Otherwise delegate the change to a work queue >>>> + */ >>>> + if (!__led_need_regulator_update(led_cdev, value)) >>>> + return; >>>> + } >>>> /* If brightness setting can sleep, delegate it to a work >>>> queue task */ >>>> led_cdev->delayed_set_value = value; >>>> @@ -280,6 +317,8 @@ EXPORT_SYMBOL_GPL(led_set_brightness_nosleep); >>>> int led_set_brightness_sync(struct led_classdev *led_cdev, >>>> enum led_brightness value) >>>> { >>>> + int ret; >>>> + >>>> if (led_cdev->blink_delay_on || led_cdev->blink_delay_off) >>>> return -EBUSY; >>>> @@ -288,7 +327,15 @@ int led_set_brightness_sync(struct >>>> led_classdev *led_cdev, >>>> if (led_cdev->flags & LED_SUSPENDED) >>>> return 0; >>>> - return __led_set_brightness_blocking(led_cdev, >>>> led_cdev->brightness); >>>> + ret = __led_set_brightness_blocking(led_cdev, >>>> led_cdev->brightness); >>>> + if (ret) >>>> + return ret; >>>> + >>>> + ret = __led_handle_regulator(led_cdev, led_cdev->brightness); >>> Can't you just return here? >> ok >> >> >> thanks for the review >> >> JJ >> >>> Dan >>> >>>> + if (ret) >>>> + return ret; >>>> + >>>> + return 0; >>>> } >>>> EXPORT_SYMBOL_GPL(led_set_brightness_sync); >>>> diff --git a/include/linux/leds.h b/include/linux/leds.h >>>> index 9b2bf574a17a..bee8e3f8dddd 100644 >>>> --- a/include/linux/leds.h >>>> +++ b/include/linux/leds.h >>>> @@ -123,6 +123,10 @@ struct led_classdev { >>>> /* Ensures consistent access to the LED Flash Class device */ >>>> struct mutex led_access; >>>> + >>>> + /* regulator */ >>>> + struct regulator *regulator; >>>> + bool regulator_state; >>>> }; >>>> extern int of_led_classdev_register(struct device *parent,
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