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Date: Mon, 15 Jul 2019 11:01:29 +0200
From: Jean-Jacques Hiblot <jjhiblot@...com>
To: Dan Murphy <dmurphy@...com>, <jacek.anaszewski@...il.com>,
<pavel@....cz>, <robh+dt@...nel.org>, <mark.rutland@....com>,
<daniel.thompson@...aro.org>
CC: <linux-leds@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
<devicetree@...r.kernel.org>
Subject: Re: [PATCH 1/2] leds: Add control of the voltage/current regulator to
the LED core
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@...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.
>
> 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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