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* [PATCH v2 0/2] leds: Add control of the voltage/current regulator to the LED core
@ 2019-07-15 15:56 Jean-Jacques Hiblot
  2019-07-15 15:56 ` [PATCH v2 1/2] dt-bindings: leds: document the "power-supply" property Jean-Jacques Hiblot
  2019-07-15 15:56 ` [PATCH v2 2/2] leds: Add control of the voltage/current regulator to the LED core Jean-Jacques Hiblot
  0 siblings, 2 replies; 11+ messages in thread
From: Jean-Jacques Hiblot @ 2019-07-15 15:56 UTC (permalink / raw)
  To: jacek.anaszewski, pavel, robh+dt, mark.rutland, daniel.thompson
  Cc: dmurphy, linux-leds, linux-kernel, devicetree, Jean-Jacques Hiblot

This series makes it possible for the LED core to manage the power supply
of a LED. It uses the regulator API to disable/enable the power if when the
LED is turned on/off.
This is especially useful in situations where the LED driver/controller is
not supplying the power.

changes in v2:
- use devm_regulator_get_optional() to avoid using the dummy regulator and do
  some unnecessary work

Jean-Jacques Hiblot (2):
  dt-bindings: leds: document the "power-supply" property
  leds: Add control of the voltage/current regulator to the LED core

 .../devicetree/bindings/leds/common.txt       |  6 +++
 drivers/leds/led-class.c                      | 15 ++++++
 drivers/leds/led-core.c                       | 50 +++++++++++++++++--
 drivers/leds/leds.h                           |  1 +
 include/linux/leds.h                          |  4 ++
 5 files changed, 73 insertions(+), 3 deletions(-)

-- 
2.17.1


^ permalink raw reply	[flat|nested] 11+ messages in thread

* [PATCH v2 1/2] dt-bindings: leds: document the "power-supply" property
  2019-07-15 15:56 [PATCH v2 0/2] leds: Add control of the voltage/current regulator to the LED core Jean-Jacques Hiblot
@ 2019-07-15 15:56 ` Jean-Jacques Hiblot
  2019-07-15 18:52   ` Dan Murphy
  2019-08-19 11:31   ` Pavel Machek
  2019-07-15 15:56 ` [PATCH v2 2/2] leds: Add control of the voltage/current regulator to the LED core Jean-Jacques Hiblot
  1 sibling, 2 replies; 11+ messages in thread
From: Jean-Jacques Hiblot @ 2019-07-15 15:56 UTC (permalink / raw)
  To: jacek.anaszewski, pavel, robh+dt, mark.rutland, daniel.thompson
  Cc: dmurphy, linux-leds, linux-kernel, devicetree, Jean-Jacques Hiblot

Most of the LEDs are powered by a voltage/current regulator. Describing it
in the device-tree makes it possible for the LED core to enable/disable it
when needed.

Signed-off-by: Jean-Jacques Hiblot <jjhiblot@ti.com>
---
 Documentation/devicetree/bindings/leds/common.txt | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/Documentation/devicetree/bindings/leds/common.txt b/Documentation/devicetree/bindings/leds/common.txt
index 70876ac11367..539e124b1457 100644
--- a/Documentation/devicetree/bindings/leds/common.txt
+++ b/Documentation/devicetree/bindings/leds/common.txt
@@ -61,6 +61,11 @@ Optional properties for child nodes:
 - panic-indicator : This property specifies that the LED should be used,
 		    if at all possible, as a panic indicator.
 
+- power-supply : A voltage/current regulator used to to power the LED. When a
+		 LED is turned off, the LED core disable its regulator. The
+		 same regulator can power many LED (or other) devices. It is
+		 turned off only when all of its users disabled it.
+
 - trigger-sources : List of devices which should be used as a source triggering
 		    this LED activity. Some LEDs can be related to a specific
 		    device and should somehow indicate its state. E.g. USB 2.0
@@ -106,6 +111,7 @@ gpio-leds {
 		label = "Status";
 		linux,default-trigger = "heartbeat";
 		gpios = <&gpio0 0 GPIO_ACTIVE_HIGH>;
+		power-supply = <&led_regulator>;
 	};
 
 	usb {
-- 
2.17.1


^ permalink raw reply	[flat|nested] 11+ messages in thread

* [PATCH v2 2/2] leds: Add control of the voltage/current regulator to the LED core
  2019-07-15 15:56 [PATCH v2 0/2] leds: Add control of the voltage/current regulator to the LED core Jean-Jacques Hiblot
  2019-07-15 15:56 ` [PATCH v2 1/2] dt-bindings: leds: document the "power-supply" property Jean-Jacques Hiblot
@ 2019-07-15 15:56 ` Jean-Jacques Hiblot
  2019-07-15 18:59   ` Dan Murphy
                     ` (2 more replies)
  1 sibling, 3 replies; 11+ messages in thread
From: Jean-Jacques Hiblot @ 2019-07-15 15:56 UTC (permalink / raw)
  To: jacek.anaszewski, pavel, robh+dt, mark.rutland, daniel.thompson
  Cc: dmurphy, linux-leds, linux-kernel, devicetree, Jean-Jacques Hiblot

A LED is usually powered by a voltage/current regulator. 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 | 15 ++++++++++++
 drivers/leds/led-core.c  | 50 +++++++++++++++++++++++++++++++++++++---
 drivers/leds/leds.h      |  1 +
 include/linux/leds.h     |  4 ++++
 4 files changed, 67 insertions(+), 3 deletions(-)

diff --git a/drivers/leds/led-class.c b/drivers/leds/led-class.c
index 4793e77808e2..cadd43c30d50 100644
--- a/drivers/leds/led-class.c
+++ b/drivers/leds/led-class.c
@@ -253,6 +253,7 @@ int of_led_classdev_register(struct device *parent, struct device_node *np,
 {
 	char name[LED_MAX_NAME_SIZE];
 	int ret;
+	struct regulator *regulator;
 
 	ret = led_classdev_next_name(led_cdev->name, name, sizeof(name));
 	if (ret < 0)
@@ -272,6 +273,20 @@ 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));
 
+	regulator = devm_regulator_get_optional(led_cdev->dev, "power");
+	if (IS_ERR(regulator)) {
+		if (PTR_ERR(regulator) != -ENODEV) {
+			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(regulator);
+		}
+		led_cdev->regulator = NULL;
+	} else {
+		led_cdev->regulator = regulator;
+	}
+
 	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..a12b880b0a2f 100644
--- a/drivers/leds/led-core.c
+++ b/drivers/leds/led-core.c
@@ -23,6 +23,33 @@ 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_state = (brightness != LED_OFF);
+
+	return led_cdev->regulator && led_cdev->regulator_state != new_state;
+}
+
+static int __led_handle_regulator(struct led_classdev *led_cdev,
+				int brightness)
+{
+	int rc;
+
+	if (__led_need_regulator_update(led_cdev, brightness)) {
+
+		if (brightness != LED_OFF)
+			rc = regulator_enable(led_cdev->regulator);
+		else
+			rc = regulator_disable(led_cdev->regulator);
+		if (rc)
+			return rc;
+
+		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 +107,7 @@ static void led_timer_function(struct timer_list *t)
 	}
 
 	led_set_brightness_nosleep(led_cdev, brightness);
+	__led_handle_regulator(led_cdev, brightness);
 
 	/* 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 +143,8 @@ 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 +171,7 @@ 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 +179,7 @@ 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 +288,14 @@ 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 +318,8 @@ 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 +328,11 @@ 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;
+
+	return __led_handle_regulator(led_cdev, led_cdev->brightness);
 }
 EXPORT_SYMBOL_GPL(led_set_brightness_sync);
 
diff --git a/drivers/leds/leds.h b/drivers/leds/leds.h
index 47b229469069..5aa5c038bd38 100644
--- a/drivers/leds/leds.h
+++ b/drivers/leds/leds.h
@@ -11,6 +11,7 @@
 
 #include <linux/rwsem.h>
 #include <linux/leds.h>
+#include <linux/regulator/consumer.h>
 
 static inline int led_get_brightness(struct led_classdev *led_cdev)
 {
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,
-- 
2.17.1


^ permalink raw reply	[flat|nested] 11+ messages in thread

* Re: [PATCH v2 1/2] dt-bindings: leds: document the "power-supply" property
  2019-07-15 15:56 ` [PATCH v2 1/2] dt-bindings: leds: document the "power-supply" property Jean-Jacques Hiblot
@ 2019-07-15 18:52   ` Dan Murphy
  2019-08-19 11:31   ` Pavel Machek
  1 sibling, 0 replies; 11+ messages in thread
From: Dan Murphy @ 2019-07-15 18:52 UTC (permalink / raw)
  To: Jean-Jacques Hiblot, jacek.anaszewski, pavel, robh+dt,
	mark.rutland, daniel.thompson
  Cc: linux-leds, linux-kernel, devicetree

JJ

On 7/15/19 10:56 AM, Jean-Jacques Hiblot wrote:
> Most of the LEDs are powered by a voltage/current regulator. Describing it
> in the device-tree makes it possible for the LED core to enable/disable it
> when needed.
>
> Signed-off-by: Jean-Jacques Hiblot <jjhiblot@ti.com>
> ---
>   Documentation/devicetree/bindings/leds/common.txt | 6 ++++++
>   1 file changed, 6 insertions(+)
>
> diff --git a/Documentation/devicetree/bindings/leds/common.txt b/Documentation/devicetree/bindings/leds/common.txt
> index 70876ac11367..539e124b1457 100644
> --- a/Documentation/devicetree/bindings/leds/common.txt
> +++ b/Documentation/devicetree/bindings/leds/common.txt
> @@ -61,6 +61,11 @@ Optional properties for child nodes:
>   - panic-indicator : This property specifies that the LED should be used,
>   		    if at all possible, as a panic indicator.
>   
> +- power-supply : A voltage/current regulator used to to power the LED. When a
Is the phandle to a voltage/current regulator used to to power the LED
> +		 LED is turned off, the LED core disable its regulator. The
The regulator is only disabled if it is the only consumer and/or the 
number of users = 0.
> +		 same regulator can power many LED (or other) devices. It is
> +		 turned off only when all of its users disabled it.
> +
>   - trigger-sources : List of devices which should be used as a source triggering
>   		    this LED activity. Some LEDs can be related to a specific
>   		    device and should somehow indicate its state. E.g. USB 2.0
> @@ -106,6 +111,7 @@ gpio-leds {
>   		label = "Status";
>   		linux,default-trigger = "heartbeat";
>   		gpios = <&gpio0 0 GPIO_ACTIVE_HIGH>;
> +		power-supply = <&led_regulator>;
>   	};
>   
>   	usb {


Reviewed-by: Dan Murphy <dmurphy@ti.com>


^ permalink raw reply	[flat|nested] 11+ messages in thread

* Re: [PATCH v2 2/2] leds: Add control of the voltage/current regulator to the LED core
  2019-07-15 15:56 ` [PATCH v2 2/2] leds: Add control of the voltage/current regulator to the LED core Jean-Jacques Hiblot
@ 2019-07-15 18:59   ` Dan Murphy
  2019-07-17 13:14     ` Jean-Jacques Hiblot
  2019-07-15 20:42   ` Jacek Anaszewski
  2019-07-16 10:50   ` Daniel Thompson
  2 siblings, 1 reply; 11+ messages in thread
From: Dan Murphy @ 2019-07-15 18:59 UTC (permalink / raw)
  To: Jean-Jacques Hiblot, jacek.anaszewski, pavel, robh+dt,
	mark.rutland, daniel.thompson
  Cc: linux-leds, linux-kernel, devicetree

JJ

On 7/15/19 10:56 AM, Jean-Jacques Hiblot wrote:
> A LED is usually powered by a voltage/current regulator. Let the LED core
> know about it. This allows the LED core to turn on or off the power supply
> as needed.

This allows the LED core to turn on or off managed power supplies.


>
> Signed-off-by: Jean-Jacques Hiblot <jjhiblot@ti.com>
> ---
>   drivers/leds/led-class.c | 15 ++++++++++++
>   drivers/leds/led-core.c  | 50 +++++++++++++++++++++++++++++++++++++---
>   drivers/leds/leds.h      |  1 +
>   include/linux/leds.h     |  4 ++++
>   4 files changed, 67 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/leds/led-class.c b/drivers/leds/led-class.c
> index 4793e77808e2..cadd43c30d50 100644
> --- a/drivers/leds/led-class.c
> +++ b/drivers/leds/led-class.c
> @@ -253,6 +253,7 @@ int of_led_classdev_register(struct device *parent, struct device_node *np,
>   {
>   	char name[LED_MAX_NAME_SIZE];
>   	int ret;
> +	struct regulator *regulator;
>   
>   	ret = led_classdev_next_name(led_cdev->name, name, sizeof(name));
>   	if (ret < 0)
> @@ -272,6 +273,20 @@ 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));
>   
> +	regulator = devm_regulator_get_optional(led_cdev->dev, "power");
Store the regulator in  led_cdev->regulator and drop the else case below.
> +	if (IS_ERR(regulator)) {
> +		if (PTR_ERR(regulator) != -ENODEV) {
> +			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(regulator);
> +		}
> +		led_cdev->regulator = NULL;
> +	} else {
> +		led_cdev->regulator = regulator;
> +	}
> +
>   	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..a12b880b0a2f 100644
> --- a/drivers/leds/led-core.c
> +++ b/drivers/leds/led-core.c
> @@ -23,6 +23,33 @@ 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_state = (brightness != LED_OFF);
> +
> +	return led_cdev->regulator && led_cdev->regulator_state != new_state;
> +}
> +
> +static int __led_handle_regulator(struct led_classdev *led_cdev,
> +				int brightness)
> +{
> +	int rc;

Should there be a check for the regulator pointer.

If (!led_cdev->regulator)

     return 0;


Otherwise

Reviewed-by: Dan Murphy <dmurphy@ti.com>

<snip>


^ permalink raw reply	[flat|nested] 11+ messages in thread

* Re: [PATCH v2 2/2] leds: Add control of the voltage/current regulator to the LED core
  2019-07-15 15:56 ` [PATCH v2 2/2] leds: Add control of the voltage/current regulator to the LED core Jean-Jacques Hiblot
  2019-07-15 18:59   ` Dan Murphy
@ 2019-07-15 20:42   ` Jacek Anaszewski
  2019-07-17 13:23     ` Jean-Jacques Hiblot
  2019-07-16 10:50   ` Daniel Thompson
  2 siblings, 1 reply; 11+ messages in thread
From: Jacek Anaszewski @ 2019-07-15 20:42 UTC (permalink / raw)
  To: Jean-Jacques Hiblot, pavel, robh+dt, mark.rutland, daniel.thompson
  Cc: dmurphy, linux-leds, linux-kernel, devicetree

Hi Jean,

Thank you for the patch.

I have one issue. Please refer below.

On 7/15/19 5:56 PM, Jean-Jacques Hiblot wrote:
> A LED is usually powered by a voltage/current regulator. 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 | 15 ++++++++++++
>  drivers/leds/led-core.c  | 50 +++++++++++++++++++++++++++++++++++++---
>  drivers/leds/leds.h      |  1 +
>  include/linux/leds.h     |  4 ++++
>  4 files changed, 67 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/leds/led-class.c b/drivers/leds/led-class.c
> index 4793e77808e2..cadd43c30d50 100644
> --- a/drivers/leds/led-class.c
> +++ b/drivers/leds/led-class.c
> @@ -253,6 +253,7 @@ int of_led_classdev_register(struct device *parent, struct device_node *np,
>  {
>  	char name[LED_MAX_NAME_SIZE];
>  	int ret;
> +	struct regulator *regulator;
>  
>  	ret = led_classdev_next_name(led_cdev->name, name, sizeof(name));
>  	if (ret < 0)
> @@ -272,6 +273,20 @@ 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));
>  
> +	regulator = devm_regulator_get_optional(led_cdev->dev, "power");
> +	if (IS_ERR(regulator)) {
> +		if (PTR_ERR(regulator) != -ENODEV) {
> +			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(regulator);
> +		}
> +		led_cdev->regulator = NULL;
> +	} else {
> +		led_cdev->regulator = regulator;
> +	}
> +
>  	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..a12b880b0a2f 100644
> --- a/drivers/leds/led-core.c
> +++ b/drivers/leds/led-core.c
> @@ -23,6 +23,33 @@ 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_state = (brightness != LED_OFF);
> +
> +	return led_cdev->regulator && led_cdev->regulator_state != new_state;
> +}
> +
> +static int __led_handle_regulator(struct led_classdev *led_cdev,
> +				int brightness)
> +{
> +	int rc;
> +
> +	if (__led_need_regulator_update(led_cdev, brightness)) {
> +
> +		if (brightness != LED_OFF)
> +			rc = regulator_enable(led_cdev->regulator);
> +		else
> +			rc = regulator_disable(led_cdev->regulator);
> +		if (rc)
> +			return rc;
> +
> +		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 +107,7 @@ static void led_timer_function(struct timer_list *t)
>  	}
>  
>  	led_set_brightness_nosleep(led_cdev, brightness);
> +	__led_handle_regulator(led_cdev, brightness);

This cannot be called from atomic context since regulator_enable/disable
use mutex beneath, that can sleep on contention. Therefore this call
has to be made in two places instead:

__led_set_brightness()
__led_set_brightness_blocking()

>  
>  	/* 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 +143,8 @@ 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 +171,7 @@ 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 +179,7 @@ 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 +288,14 @@ 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 +318,8 @@ 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 +328,11 @@ 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;
> +
> +	return __led_handle_regulator(led_cdev, led_cdev->brightness);
>  }
>  EXPORT_SYMBOL_GPL(led_set_brightness_sync);
>  
> diff --git a/drivers/leds/leds.h b/drivers/leds/leds.h
> index 47b229469069..5aa5c038bd38 100644
> --- a/drivers/leds/leds.h
> +++ b/drivers/leds/leds.h
> @@ -11,6 +11,7 @@
>  
>  #include <linux/rwsem.h>
>  #include <linux/leds.h>
> +#include <linux/regulator/consumer.h>
>  
>  static inline int led_get_brightness(struct led_classdev *led_cdev)
>  {
> 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,
> 

-- 
Best regards,
Jacek Anaszewski

^ permalink raw reply	[flat|nested] 11+ messages in thread

* Re: [PATCH v2 2/2] leds: Add control of the voltage/current regulator to the LED core
  2019-07-15 15:56 ` [PATCH v2 2/2] leds: Add control of the voltage/current regulator to the LED core Jean-Jacques Hiblot
  2019-07-15 18:59   ` Dan Murphy
  2019-07-15 20:42   ` Jacek Anaszewski
@ 2019-07-16 10:50   ` Daniel Thompson
  2019-07-17 13:47     ` Jean-Jacques Hiblot
  2 siblings, 1 reply; 11+ messages in thread
From: Daniel Thompson @ 2019-07-16 10:50 UTC (permalink / raw)
  To: Jean-Jacques Hiblot
  Cc: jacek.anaszewski, pavel, robh+dt, mark.rutland, dmurphy,
	linux-leds, linux-kernel, devicetree

On Mon, Jul 15, 2019 at 05:56:57PM +0200, Jean-Jacques Hiblot wrote:
> A LED is usually powered by a voltage/current regulator. Let the LED core

This is almost certainly nitpicking but since there's enough other
review comments that you will have to respin anyway ;-)

Is an LED really "usually powered by a voltage/current regulator"? Some
LEDs have a software controlled power supply but I'm not sure it is
the usual case.

Likewise its a little confusing to be talking about LEDs with an
external current regulator since, although that is possible, it is also
one the main features provided by LED driver chips.


Daniel.

^ permalink raw reply	[flat|nested] 11+ messages in thread

* Re: [PATCH v2 2/2] leds: Add control of the voltage/current regulator to the LED core
  2019-07-15 18:59   ` Dan Murphy
@ 2019-07-17 13:14     ` Jean-Jacques Hiblot
  0 siblings, 0 replies; 11+ messages in thread
From: Jean-Jacques Hiblot @ 2019-07-17 13:14 UTC (permalink / raw)
  To: Dan Murphy, jacek.anaszewski, pavel, robh+dt, mark.rutland,
	daniel.thompson
  Cc: linux-leds, linux-kernel, devicetree

Hi Dan,

On 15/07/2019 20:59, Dan Murphy wrote:
> JJ
>
> On 7/15/19 10:56 AM, Jean-Jacques Hiblot wrote:
>> A LED is usually powered by a voltage/current regulator. Let the LED 
>> core
>> know about it. This allows the LED core to turn on or off the power 
>> supply
>> as needed.
>
> This allows the LED core to turn on or off managed power supplies.
>
>
>>
>> Signed-off-by: Jean-Jacques Hiblot <jjhiblot@ti.com>
>> ---

>>       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..a12b880b0a2f 100644
>> --- a/drivers/leds/led-core.c
>> +++ b/drivers/leds/led-core.c
>> @@ -23,6 +23,33 @@ 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_state = (brightness != LED_OFF);
>> +
>> +    return led_cdev->regulator && led_cdev->regulator_state != 
>> new_state;
>> +}
>> +
>> +static int __led_handle_regulator(struct led_classdev *led_cdev,
>> +                int brightness)
>> +{
>> +    int rc;
>
> Should there be a check for the regulator pointer.
>
> If (!led_cdev->regulator)
>
>     return 0;

Not required because __led_need_regulator_update() returns false if 
led_cdev->regulator is NULL.

Thanks for the review

JJ

>
>
> Otherwise
>
> Reviewed-by: Dan Murphy <dmurphy@ti.com>
>
> <snip>
>

^ permalink raw reply	[flat|nested] 11+ messages in thread

* Re: [PATCH v2 2/2] leds: Add control of the voltage/current regulator to the LED core
  2019-07-15 20:42   ` Jacek Anaszewski
@ 2019-07-17 13:23     ` Jean-Jacques Hiblot
  0 siblings, 0 replies; 11+ messages in thread
From: Jean-Jacques Hiblot @ 2019-07-17 13:23 UTC (permalink / raw)
  To: Jacek Anaszewski, pavel, mark.rutland, daniel.thompson
  Cc: dmurphy, linux-leds, linux-kernel

Hi Jacek,

On 15/07/2019 22:42, Jacek Anaszewski wrote:
> @@ -80,6 +107,7 @@ static void led_timer_function(struct timer_list *t)
>   	}
>   
>   	led_set_brightness_nosleep(led_cdev, brightness);
> +	__led_handle_regulator(led_cdev, brightness);
> This cannot be called from atomic context since regulator_enable/disable
> use mutex beneath, that can sleep on contention. Therefore this call
> has to be made in two places instead:
>
> __led_set_brightness()
> __led_set_brightness_blocking()

Thanks. I'll fix this in v3.

JJ

^ permalink raw reply	[flat|nested] 11+ messages in thread

* Re: [PATCH v2 2/2] leds: Add control of the voltage/current regulator to the LED core
  2019-07-16 10:50   ` Daniel Thompson
@ 2019-07-17 13:47     ` Jean-Jacques Hiblot
  0 siblings, 0 replies; 11+ messages in thread
From: Jean-Jacques Hiblot @ 2019-07-17 13:47 UTC (permalink / raw)
  To: Daniel Thompson
  Cc: jacek.anaszewski, pavel, robh+dt, mark.rutland, dmurphy,
	linux-leds, linux-kernel, devicetree


On 16/07/2019 12:50, Daniel Thompson wrote:
> On Mon, Jul 15, 2019 at 05:56:57PM +0200, Jean-Jacques Hiblot wrote:
>> A LED is usually powered by a voltage/current regulator. Let the LED core
> This is almost certainly nitpicking but since there's enough other
> review comments that you will have to respin anyway ;-)
No problems. comments are welcome.
> Is an LED really "usually powered by a voltage/current regulator"? Some
> LEDs have a software controlled power supply but I'm not sure it is
> the usual case.
True. I'll reword this.
> Likewise its a little confusing to be talking about LEDs with an
> external current regulator since, although that is possible, it is also
> one the main features provided by LED driver chips.

In my experience LED drivers are quite often current sinks. In that case 
the power is provided externally, and sometimes by a managed regulator.

Thanks,

JJ

>
> Daniel.

^ permalink raw reply	[flat|nested] 11+ messages in thread

* Re: [PATCH v2 1/2] dt-bindings: leds: document the "power-supply" property
  2019-07-15 15:56 ` [PATCH v2 1/2] dt-bindings: leds: document the "power-supply" property Jean-Jacques Hiblot
  2019-07-15 18:52   ` Dan Murphy
@ 2019-08-19 11:31   ` Pavel Machek
  1 sibling, 0 replies; 11+ messages in thread
From: Pavel Machek @ 2019-08-19 11:31 UTC (permalink / raw)
  To: Jean-Jacques Hiblot
  Cc: jacek.anaszewski, robh+dt, mark.rutland, daniel.thompson,
	dmurphy, linux-leds, linux-kernel, devicetree

[-- Attachment #1: Type: text/plain, Size: 470 bytes --]

On Mon 2019-07-15 17:56:56, Jean-Jacques Hiblot wrote:
> Most of the LEDs are powered by a voltage/current regulator. Describing it
> in the device-tree makes it possible for the LED core to enable/disable it
> when needed.
> 
> Signed-off-by: Jean-Jacques Hiblot <jjhiblot@ti.com>

Acked-by: Pavel Machek <pavel@ucw.cz>

-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

[-- Attachment #2: Digital signature --]
[-- Type: application/pgp-signature, Size: 181 bytes --]

^ permalink raw reply	[flat|nested] 11+ messages in thread

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Thread overview: 11+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2019-07-15 15:56 [PATCH v2 0/2] leds: Add control of the voltage/current regulator to the LED core Jean-Jacques Hiblot
2019-07-15 15:56 ` [PATCH v2 1/2] dt-bindings: leds: document the "power-supply" property Jean-Jacques Hiblot
2019-07-15 18:52   ` Dan Murphy
2019-08-19 11:31   ` Pavel Machek
2019-07-15 15:56 ` [PATCH v2 2/2] leds: Add control of the voltage/current regulator to the LED core Jean-Jacques Hiblot
2019-07-15 18:59   ` Dan Murphy
2019-07-17 13:14     ` Jean-Jacques Hiblot
2019-07-15 20:42   ` Jacek Anaszewski
2019-07-17 13:23     ` Jean-Jacques Hiblot
2019-07-16 10:50   ` Daniel Thompson
2019-07-17 13:47     ` Jean-Jacques Hiblot

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