From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dan Murphy Subject: Re: [PATCH 1/2] leds: Add control of the voltage/current regulator to the LED core Date: Fri, 12 Jul 2019 13:49:21 -0500 Message-ID: <56d16260-ff82-3439-4c1f-2a3a1552bc7d@ti.com> References: <20190708103547.23528-1-jjhiblot@ti.com> <20190708103547.23528-2-jjhiblot@ti.com> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8"; format=flowed Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: <20190708103547.23528-2-jjhiblot@ti.com> Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org To: Jean-Jacques Hiblot , 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 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? > + 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. 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. > + > + 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? 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,