From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jean-Jacques Hiblot Subject: Re: [PATCH 1/2] leds: Add control of the voltage/current regulator to the LED core Date: Mon, 15 Jul 2019 11:01:29 +0200 Message-ID: References: <20190708103547.23528-1-jjhiblot@ti.com> <20190708103547.23528-2-jjhiblot@ti.com> <56d16260-ff82-3439-4c1f-2a3a1552bc7d@ti.com> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8"; format=flowed Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: <56d16260-ff82-3439-4c1f-2a3a1552bc7d@ti.com> Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org To: Dan Murphy , jacek.anaszewski@gmail.com, pavel@ucw.cz, robh+dt@kernel.org, mark.rutland@arm.com, daniel.thompson@linaro.org Cc: linux-leds@vger.kernel.org, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org List-Id: devicetree@vger.kernel.org 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 >> --- >>   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 >>   #include >>   #include >> +#include > > What if you move this to leds.h so core and class can both include it. > > >>   #include >>   #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. > > 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 >>   #include >>   #include "leds.h" >> +#include >>     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,