- New Functionality

- Add new Device Tree binding for Monolithic Power (MPS) MP3309C step-up converter
    - Document brightness-levels in bindings for; generic, LED and PWM
 
  - Bug Fixes
    - Ensure PWMs are disabled on; .shutdown(), .suspend() and .remove()
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Merge tag 'backlight-next-6.7' of git://git.kernel.org/pub/scm/linux/kernel/git/lee/backlight

Pull backlight updates from Lee Jones:
 "New Functionality:

   - Add new Device Tree binding for Monolithic Power (MPS) MP3309C
     step-up converter

   - Document brightness-levels in bindings for; generic, LED and PWM

  Bug Fixes:

   - Ensure PWMs are disabled on .shutdown(), .suspend() and .remove()"

* tag 'backlight-next-6.7' of git://git.kernel.org/pub/scm/linux/kernel/git/lee/backlight:
  dt-bindings: backlight: Add brightness-levels related common properties
  backlight: pwm_bl: Disable PWM on shutdown, suspend and remove
  dt-bindings: backlight: Add MPS MP3309C

Documentation/devicetree/bindings/leds/backlight/common.yaml

@@ -33,4 +33,21 @@ properties:
       due to restrictions in a specific system, such as mounting conditions.
     $ref: /schemas/types.yaml#/definitions/uint32
 
+  brightness-levels:
+    description:
+      Array of distinct brightness levels. The levels must be in the range
+      accepted by the underlying LED device. Typically these are in the range
+      from 0 to 255, but any range starting at 0 will do, as long as they are
+      accepted by the LED.
+      The 0 value means a 0% of brightness (darkest/off), while the last value
+      in the array represents a full 100% brightness (brightest).
+      If this array is not provided, the driver default mapping is used.
+    $ref: /schemas/types.yaml#/definitions/uint32-array
+
+  default-brightness-level:
+    description:
+      The default brightness level (index into the array defined by the
+      "brightness-levels" property).
+    $ref: /schemas/types.yaml#/definitions/uint32
+
 additionalProperties: true

Documentation/devicetree/bindings/leds/backlight/led-backlight.yaml

@@ -16,6 +16,9 @@ description:
   can also be used to describe a backlight device controlled by the output of
   a LED driver.
 
+allOf:
+  - $ref: common.yaml#
+
 properties:
   compatible:
     const: led-backlight
@@ -26,25 +29,11 @@ properties:
     items:
       maxItems: 1
 
-  brightness-levels:
-    description:
-      Array of distinct brightness levels. The levels must be in the range
-      accepted by the underlying LED devices. This is used to translate a
-      backlight brightness level into a LED brightness level. If it is not
-      provided, the identity mapping is used.
-    $ref: /schemas/types.yaml#/definitions/uint32-array
-
-  default-brightness-level:
-    description:
-      The default brightness level (index into the array defined by the
-      "brightness-levels" property).
-    $ref: /schemas/types.yaml#/definitions/uint32
-
 required:
   - compatible
   - leds
 
-additionalProperties: false
+unevaluatedProperties: false
 
 examples:
   - |

Documentation/devicetree/bindings/leds/backlight/mps,mp3309c.yaml

@@ -0,0 +1,73 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/leds/backlight/mps,mp3309c.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: MPS MP3309C backlight
+
+maintainers:
+  - Flavio Suligoi <f.suligoi@asem.it>
+
+description: |
+  The Monolithic Power (MPS) MP3309C is a WLED step-up converter, featuring a
+  programmable switching frequency to optimize efficiency.
+  It supports two different dimming modes:
+
+  - analog mode, via I2C commands (default)
+  - PWM controlled mode.
+
+  The datasheet is available at:
+  https://www.monolithicpower.com/en/mp3309c.html
+
+allOf:
+  - $ref: common.yaml#
+
+properties:
+  compatible:
+    const: mps,mp3309c
+
+  reg:
+    maxItems: 1
+
+  pwms:
+    description: if present, the backlight is controlled in PWM mode.
+    maxItems: 1
+
+  enable-gpios:
+    description: GPIO used to enable the backlight in "analog-i2c" dimming mode.
+    maxItems: 1
+
+  mps,overvoltage-protection-microvolt:
+    description: Overvoltage protection (13.5V, 24V or 35.5V).
+    enum: [ 13500000, 24000000, 35500000 ]
+    default: 35500000
+
+  mps,no-sync-mode:
+    description: disable synchronous rectification mode
+    type: boolean
+
+required:
+  - compatible
+  - reg
+  - max-brightness
+  - default-brightness
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    i2c {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        /* Backlight with PWM control */
+        backlight_pwm: backlight@17 {
+            compatible = "mps,mp3309c";
+            reg = <0x17>;
+            pwms = <&pwm1 0 3333333 0>; /* 300 Hz --> (1/f) * 1*10^9 */
+            max-brightness = <100>;
+            default-brightness = <80>;
+            mps,overvoltage-protection-microvolt = <24000000>;
+        };
+    };

Documentation/devicetree/bindings/leds/backlight/pwm-backlight.yaml

@@ -11,6 +11,9 @@ maintainers:
   - Daniel Thompson <daniel.thompson@linaro.org>
   - Jingoo Han <jingoohan1@gmail.com>
 
+allOf:
+  - $ref: common.yaml#
+
 properties:
   compatible:
     const: pwm-backlight
@@ -39,21 +42,6 @@ properties:
       Delay in ms between disabling the backlight using GPIO and setting PWM
       value to 0.
 
-  brightness-levels:
-    description:
-      Array of distinct brightness levels. Typically these are in the range
-      from 0 to 255, but any range starting at 0 will do. The actual brightness
-      level (PWM duty cycle) will be interpolated from these values. 0 means a
-      0% duty cycle (darkest/off), while the last value in the array represents
-      a 100% duty cycle (brightest).
-    $ref: /schemas/types.yaml#/definitions/uint32-array
-
-  default-brightness-level:
-    description:
-      The default brightness level (index into the array defined by the
-      "brightness-levels" property).
-    $ref: /schemas/types.yaml#/definitions/uint32
-
   num-interpolated-steps:
     description:
       Number of interpolated steps between each value of brightness-levels
@@ -69,7 +57,7 @@ required:
   - compatible
   - pwms
 
-additionalProperties: false
+unevaluatedProperties: false
 
 examples:
   - |

drivers/video/backlight/pwm_bl.c

@@ -626,9 +626,14 @@ static void pwm_backlight_remove(struct platform_device *pdev)
 {
 	struct backlight_device *bl = platform_get_drvdata(pdev);
 	struct pwm_bl_data *pb = bl_get_data(bl);
+	struct pwm_state state;
 
 	backlight_device_unregister(bl);
 	pwm_backlight_power_off(pb);
+	pwm_get_state(pb->pwm, &state);
+	state.duty_cycle = 0;
+	state.enabled = false;
+	pwm_apply_state(pb->pwm, &state);
 
 	if (pb->exit)
 		pb->exit(&pdev->dev);
@@ -638,8 +643,13 @@ static void pwm_backlight_shutdown(struct platform_device *pdev)
 {
 	struct backlight_device *bl = platform_get_drvdata(pdev);
 	struct pwm_bl_data *pb = bl_get_data(bl);
+	struct pwm_state state;
 
 	pwm_backlight_power_off(pb);
+	pwm_get_state(pb->pwm, &state);
+	state.duty_cycle = 0;
+	state.enabled = false;
+	pwm_apply_state(pb->pwm, &state);
 }
 
 #ifdef CONFIG_PM_SLEEP
@@ -647,12 +657,24 @@ static int pwm_backlight_suspend(struct device *dev)
 {
 	struct backlight_device *bl = dev_get_drvdata(dev);
 	struct pwm_bl_data *pb = bl_get_data(bl);
+	struct pwm_state state;
 
 	if (pb->notify)
 		pb->notify(pb->dev, 0);
 
 	pwm_backlight_power_off(pb);
 
+	/*
+	 * Note that disabling the PWM doesn't guarantee that the output stays
+	 * at its inactive state. However without the PWM disabled, the PWM
+	 * driver refuses to suspend. So disable here even though this might
+	 * enable the backlight on poorly designed boards.
+	 */
+	pwm_get_state(pb->pwm, &state);
+	state.duty_cycle = 0;
+	state.enabled = false;
+	pwm_apply_state(pb->pwm, &state);
+
 	if (pb->notify_after)
 		pb->notify_after(pb->dev, 0);