Merge tag 'backlight-next-6.9' of git://git.kernel.org/pub/scm/linux/kernel/git/lee/backlight

Pull backlight updates from Lee Jones:
 "New Drivers:
   - Add support for Kinetic KTD2801 Backlight

  Fix-ups:
   - Fix include lists; alphabetise, remove unused, explicitly add used
   - Device Tree binding adaptions/conversions/creation
   - Use dev_err_probe() to clean-up error paths
   - Use/convert to new/better APIs/helpers/MACROs instead of hand-rolling implementations

  Bug Fixes:
   - Fix changes of NULL pointer dereference
   - Remedy a bunch of logic errors
   - Initialise (zero) Backlight properties data structures"

* tag 'backlight-next-6.9' of git://git.kernel.org/pub/scm/linux/kernel/git/lee/backlight: (32 commits)
  backlight: pandora_bl: Drop unneeded ENOMEM error message
  backlight: lm3630a_bl: Simplify probe return on gpio request error
  backlight: lm3630a_bl: Handle deferred probe
  backlight: as3711_bl: Handle deferred probe
  backlight: bd6107: Handle deferred probe
  backlight: l4f00242t03: Simplify with dev_err_probe()
  backlight: gpio: Simplify with dev_err_probe()
  backlight: lp8788: Fully initialize backlight_properties during probe
  backlight: lm3639: Fully initialize backlight_properties during probe
  backlight: da9052: Fully initialize backlight_properties during probe
  backlight: lm3630a: Use backlight_get_brightness helper in update_status
  backlight: lm3630a: Don't set bl->props.brightness in get_brightness
  backlight: lm3630a: Initialize backlight_properties on init
  backlight: mp3309c: Fully initialize backlight_properties during probe
  backlight: mp3309c: Utilise temporary variable for struct device
  backlight: mp3309c: Use dev_err_probe() instead of dev_err()
  backlight: mp3309c: Make use of device properties
  dt-bindings: backlight: qcom-wled: Fix bouncing email addresses
  backlight: hx8357: Utilise temporary variable for struct device
  backlight: hx8357: Make use of dev_err_probe()
  ...

Author: torvalds

Documentation/devicetree/bindings/leds/backlight/kinetic,ktd2801.yaml

@@ -0,0 +1,46 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/leds/backlight/kinetic,ktd2801.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Kinetic Technologies KTD2801 one-wire backlight
+
+maintainers:
+  - Duje Mihanović <[email protected]>
+
+description: |
+  The Kinetic Technologies KTD2801 is a LED backlight driver controlled
+  by a single GPIO line. The driver can be controlled with a PWM signal
+  or by pulsing the GPIO line to set the backlight level. This is called
+  "ExpressWire".
+
+allOf:
+  - $ref: common.yaml#
+
+properties:
+  compatible:
+    const: kinetic,ktd2801
+
+  ctrl-gpios:
+    maxItems: 1
+
+  default-brightness: true
+  max-brightness: true
+
+required:
+  - compatible
+  - ctrl-gpios
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/gpio/gpio.h>
+
+    backlight {
+        compatible = "kinetic,ktd2801";
+        ctrl-gpios = <&gpio 97 GPIO_ACTIVE_HIGH>;
+        max-brightness = <210>;
+        default-brightness = <100>;
+    };

Documentation/devicetree/bindings/leds/backlight/qcom-wled.yaml

@@ -7,8 +7,8 @@ $schema: http://devicetree.org/meta-schemas/core.yaml#
 title: Qualcomm Technologies, Inc. WLED driver
 
 maintainers:
-  - Bjorn Andersson <bjorn.andersson@linaro.org>
-  - Kiran Gunda <[email protected]>
+  - Bjorn Andersson <andersson@kernel.org>
+  - Kiran Gunda <[email protected]>
 
 description: |
   WLED (White Light Emitting Diode) driver is used for controlling display

MAINTAINERS

@@ -8039,6 +8039,13 @@ S:	Maintained
 T:	git git://git.kernel.org/pub/scm/linux/kernel/git/linkinjeon/exfat.git
 F:	fs/exfat/
 
+EXPRESSWIRE PROTOCOL LIBRARY
+M:	Duje Mihanović <[email protected]>
+L:	[email protected]
+S:	Maintained
+F:	drivers/leds/leds-expresswire.c
+F:	include/linux/leds-expresswire.h
+
 EXT2 FILE SYSTEM
 M:	Jan Kara <[email protected]>
 L:	[email protected]
@@ -12103,6 +12110,12 @@ S:	Maintained
 F:	Documentation/devicetree/bindings/leds/backlight/kinetic,ktd253.yaml
 F:	drivers/video/backlight/ktd253-backlight.c
 
+KTD2801 BACKLIGHT DRIVER
+M:	Duje Mihanović <[email protected]>
+S:	Maintained
+F:	Documentation/devicetree/bindings/leds/backlight/kinetic,ktd2801.yaml
+F:	drivers/video/backlight/ktd2801-backlight.c
+
 KTEST
 M:	Steven Rostedt <[email protected]>
 M:	John Hawley <[email protected]>

drivers/leds/Kconfig

@@ -186,6 +186,10 @@ config LEDS_EL15203000
 	  To compile this driver as a module, choose M here: the module
 	  will be called leds-el15203000.
 
+config LEDS_EXPRESSWIRE
+	bool
+	depends on GPIOLIB
+
 config LEDS_TURRIS_OMNIA
 	tristate "LED support for CZ.NIC's Turris Omnia"
 	depends on LEDS_CLASS_MULTICOLOR

drivers/leds/Makefile

@@ -91,6 +91,9 @@ obj-$(CONFIG_LEDS_WM831X_STATUS)	+= leds-wm831x-status.o
 obj-$(CONFIG_LEDS_WM8350)		+= leds-wm8350.o
 obj-$(CONFIG_LEDS_WRAP)			+= leds-wrap.o
 
+# Kinetic ExpressWire Protocol
+obj-$(CONFIG_LEDS_EXPRESSWIRE)		+= leds-expresswire.o
+
 # LED SPI Drivers
 obj-$(CONFIG_LEDS_CR0014114)		+= leds-cr0014114.o
 obj-$(CONFIG_LEDS_DAC124S085)		+= leds-dac124s085.o

drivers/leds/flash/Kconfig

@@ -23,7 +23,8 @@ config LEDS_AS3645A
 config LEDS_KTD2692
 	tristate "LED support for Kinetic KTD2692 flash LED controller"
 	depends on OF
-	depends on GPIOLIB || COMPILE_TEST
+	depends on GPIOLIB
+	select LEDS_EXPRESSWIRE
 	help
 	  This option enables support for Kinetic KTD2692 LED flash connected
 	  through ExpressWire interface.

drivers/leds/flash/leds-ktd2692.c

@@ -6,9 +6,9 @@
  * Ingi Kim <[email protected]>
  */
 
-#include <linux/delay.h>
 #include <linux/err.h>
 #include <linux/gpio/consumer.h>
+#include <linux/leds-expresswire.h>
 #include <linux/led-class-flash.h>
 #include <linux/module.h>
 #include <linux/mutex.h>
@@ -37,22 +37,9 @@
 #define KTD2692_REG_FLASH_CURRENT_BASE		0x80
 #define KTD2692_REG_MODE_BASE			0xA0
 
-/* Set bit coding time for expresswire interface */
-#define KTD2692_TIME_RESET_US			700
-#define KTD2692_TIME_DATA_START_TIME_US		10
-#define KTD2692_TIME_HIGH_END_OF_DATA_US	350
-#define KTD2692_TIME_LOW_END_OF_DATA_US		10
-#define KTD2692_TIME_SHORT_BITSET_US		4
-#define KTD2692_TIME_LONG_BITSET_US		12
-
 /* KTD2692 default length of name */
 #define KTD2692_NAME_LENGTH			20
 
-enum ktd2692_bitset {
-	KTD2692_LOW = 0,
-	KTD2692_HIGH,
-};
-
 /* Movie / Flash Mode Control */
 enum ktd2692_led_mode {
 	KTD2692_MODE_DISABLE = 0,	/* default */
@@ -71,7 +58,19 @@ struct ktd2692_led_config_data {
 	enum led_brightness max_brightness;
 };
 
+const struct expresswire_timing ktd2692_timing = {
+	.poweroff_us = 700,
+	.data_start_us = 10,
+	.end_of_data_low_us = 10,
+	.end_of_data_high_us = 350,
+	.short_bitset_us = 4,
+	.long_bitset_us = 12
+};
+
 struct ktd2692_context {
+	/* Common ExpressWire properties (ctrl GPIO and timing) */
+	struct expresswire_common_props props;
+
 	/* Related LED Flash class device */
 	struct led_classdev_flash fled_cdev;
 
@@ -80,7 +79,6 @@ struct ktd2692_context {
 	struct regulator *regulator;
 
 	struct gpio_desc *aux_gpio;
-	struct gpio_desc *ctrl_gpio;
 
 	enum ktd2692_led_mode mode;
 	enum led_brightness torch_brightness;
@@ -92,67 +90,6 @@ static struct ktd2692_context *fled_cdev_to_led(
 	return container_of(fled_cdev, struct ktd2692_context, fled_cdev);
 }
 
-static void ktd2692_expresswire_start(struct ktd2692_context *led)
-{
-	gpiod_direction_output(led->ctrl_gpio, KTD2692_HIGH);
-	udelay(KTD2692_TIME_DATA_START_TIME_US);
-}
-
-static void ktd2692_expresswire_reset(struct ktd2692_context *led)
-{
-	gpiod_direction_output(led->ctrl_gpio, KTD2692_LOW);
-	udelay(KTD2692_TIME_RESET_US);
-}
-
-static void ktd2692_expresswire_end(struct ktd2692_context *led)
-{
-	gpiod_direction_output(led->ctrl_gpio, KTD2692_LOW);
-	udelay(KTD2692_TIME_LOW_END_OF_DATA_US);
-	gpiod_direction_output(led->ctrl_gpio, KTD2692_HIGH);
-	udelay(KTD2692_TIME_HIGH_END_OF_DATA_US);
-}
-
-static void ktd2692_expresswire_set_bit(struct ktd2692_context *led, bool bit)
-{
-	/*
-	 * The Low Bit(0) and High Bit(1) is based on a time detection
-	 * algorithm between time low and time high
-	 * Time_(L_LB) : Low time of the Low Bit(0)
-	 * Time_(H_LB) : High time of the LOW Bit(0)
-	 * Time_(L_HB) : Low time of the High Bit(1)
-	 * Time_(H_HB) : High time of the High Bit(1)
-	 *
-	 * It can be simplified to:
-	 * Low Bit(0) : 2 * Time_(H_LB) < Time_(L_LB)
-	 * High Bit(1) : 2 * Time_(L_HB) < Time_(H_HB)
-	 * HIGH  ___           ____    _..     _________    ___
-	 *          |_________|    |_..  |____|         |__|
-	 * LOW        <L_LB>  <H_LB>     <L_HB>  <H_HB>
-	 *          [  Low Bit (0) ]     [  High Bit(1) ]
-	 */
-	if (bit) {
-		gpiod_direction_output(led->ctrl_gpio, KTD2692_LOW);
-		udelay(KTD2692_TIME_SHORT_BITSET_US);
-		gpiod_direction_output(led->ctrl_gpio, KTD2692_HIGH);
-		udelay(KTD2692_TIME_LONG_BITSET_US);
-	} else {
-		gpiod_direction_output(led->ctrl_gpio, KTD2692_LOW);
-		udelay(KTD2692_TIME_LONG_BITSET_US);
-		gpiod_direction_output(led->ctrl_gpio, KTD2692_HIGH);
-		udelay(KTD2692_TIME_SHORT_BITSET_US);
-	}
-}
-
-static void ktd2692_expresswire_write(struct ktd2692_context *led, u8 value)
-{
-	int i;
-
-	ktd2692_expresswire_start(led);
-	for (i = 7; i >= 0; i--)
-		ktd2692_expresswire_set_bit(led, value & BIT(i));
-	ktd2692_expresswire_end(led);
-}
-
 static int ktd2692_led_brightness_set(struct led_classdev *led_cdev,
 				       enum led_brightness brightness)
 {
@@ -163,14 +100,14 @@ static int ktd2692_led_brightness_set(struct led_classdev *led_cdev,
 
 	if (brightness == LED_OFF) {
 		led->mode = KTD2692_MODE_DISABLE;
-		gpiod_direction_output(led->aux_gpio, KTD2692_LOW);
+		gpiod_direction_output(led->aux_gpio, 0);
 	} else {
-		ktd2692_expresswire_write(led, brightness |
+		expresswire_write_u8(&led->props, brightness |
 					KTD2692_REG_MOVIE_CURRENT_BASE);
 		led->mode = KTD2692_MODE_MOVIE;
 	}
 
-	ktd2692_expresswire_write(led, led->mode | KTD2692_REG_MODE_BASE);
+	expresswire_write_u8(&led->props, led->mode | KTD2692_REG_MODE_BASE);
 	mutex_unlock(&led->lock);
 
 	return 0;
@@ -187,17 +124,17 @@ static int ktd2692_led_flash_strobe_set(struct led_classdev_flash *fled_cdev,
 
 	if (state) {
 		flash_tm_reg = GET_TIMEOUT_OFFSET(timeout->val, timeout->step);
-		ktd2692_expresswire_write(led, flash_tm_reg
+		expresswire_write_u8(&led->props, flash_tm_reg
 				| KTD2692_REG_FLASH_TIMEOUT_BASE);
 
 		led->mode = KTD2692_MODE_FLASH;
-		gpiod_direction_output(led->aux_gpio, KTD2692_HIGH);
+		gpiod_direction_output(led->aux_gpio, 1);
 	} else {
 		led->mode = KTD2692_MODE_DISABLE;
-		gpiod_direction_output(led->aux_gpio, KTD2692_LOW);
+		gpiod_direction_output(led->aux_gpio, 0);
 	}
 
-	ktd2692_expresswire_write(led, led->mode | KTD2692_REG_MODE_BASE);
+	expresswire_write_u8(&led->props, led->mode | KTD2692_REG_MODE_BASE);
 
 	fled_cdev->led_cdev.brightness = LED_OFF;
 	led->mode = KTD2692_MODE_DISABLE;
@@ -247,12 +184,12 @@ static void ktd2692_init_flash_timeout(struct led_classdev_flash *fled_cdev,
 static void ktd2692_setup(struct ktd2692_context *led)
 {
 	led->mode = KTD2692_MODE_DISABLE;
-	ktd2692_expresswire_reset(led);
-	gpiod_direction_output(led->aux_gpio, KTD2692_LOW);
+	expresswire_power_off(&led->props);
+	gpiod_direction_output(led->aux_gpio, 0);
 
-	ktd2692_expresswire_write(led, (KTD2692_MM_MIN_CURR_THRESHOLD_SCALE - 1)
+	expresswire_write_u8(&led->props, (KTD2692_MM_MIN_CURR_THRESHOLD_SCALE - 1)
 				 | KTD2692_REG_MM_MIN_CURR_THRESHOLD_BASE);
-	ktd2692_expresswire_write(led, KTD2692_FLASH_MODE_CURR_PERCENT(45)
+	expresswire_write_u8(&led->props, KTD2692_FLASH_MODE_CURR_PERCENT(45)
 				 | KTD2692_REG_FLASH_CURRENT_BASE);
 }
 
@@ -277,8 +214,8 @@ static int ktd2692_parse_dt(struct ktd2692_context *led, struct device *dev,
 	if (!np)
 		return -ENXIO;
 
-	led->ctrl_gpio = devm_gpiod_get(dev, "ctrl", GPIOD_ASIS);
-	ret = PTR_ERR_OR_ZERO(led->ctrl_gpio);
+	led->props.ctrl_gpio = devm_gpiod_get(dev, "ctrl", GPIOD_ASIS);
+	ret = PTR_ERR_OR_ZERO(led->props.ctrl_gpio);
 	if (ret)
 		return dev_err_probe(dev, ret, "cannot get ctrl-gpios\n");
 
@@ -412,6 +349,7 @@ static struct platform_driver ktd2692_driver = {
 
 module_platform_driver(ktd2692_driver);
 
+MODULE_IMPORT_NS(EXPRESSWIRE);
 MODULE_AUTHOR("Ingi Kim <[email protected]>");
 MODULE_DESCRIPTION("Kinetic KTD2692 LED driver");
 MODULE_LICENSE("GPL v2");

drivers/leds/leds-expresswire.c

@@ -0,0 +1,72 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Shared library for Kinetic's ExpressWire protocol.
+ * This protocol works by pulsing the ExpressWire IC's control GPIO.
+ * ktd2692 and ktd2801 are known to use this protocol.
+ */
+
+#include <linux/bits.h>
+#include <linux/delay.h>
+#include <linux/export.h>
+#include <linux/gpio/consumer.h>
+#include <linux/types.h>
+
+#include <linux/leds-expresswire.h>
+
+void expresswire_power_off(struct expresswire_common_props *props)
+{
+	gpiod_set_value_cansleep(props->ctrl_gpio, 0);
+	usleep_range(props->timing.poweroff_us, props->timing.poweroff_us * 2);
+}
+EXPORT_SYMBOL_NS_GPL(expresswire_power_off, EXPRESSWIRE);
+
+void expresswire_enable(struct expresswire_common_props *props)
+{
+	gpiod_set_value(props->ctrl_gpio, 1);
+	udelay(props->timing.detect_delay_us);
+	gpiod_set_value(props->ctrl_gpio, 0);
+	udelay(props->timing.detect_us);
+	gpiod_set_value(props->ctrl_gpio, 1);
+}
+EXPORT_SYMBOL_NS_GPL(expresswire_enable, EXPRESSWIRE);
+
+void expresswire_start(struct expresswire_common_props *props)
+{
+	gpiod_set_value(props->ctrl_gpio, 1);
+	udelay(props->timing.data_start_us);
+}
+EXPORT_SYMBOL_NS_GPL(expresswire_start, EXPRESSWIRE);
+
+void expresswire_end(struct expresswire_common_props *props)
+{
+	gpiod_set_value(props->ctrl_gpio, 0);
+	udelay(props->timing.end_of_data_low_us);
+	gpiod_set_value(props->ctrl_gpio, 1);
+	udelay(props->timing.end_of_data_high_us);
+}
+EXPORT_SYMBOL_NS_GPL(expresswire_end, EXPRESSWIRE);
+
+void expresswire_set_bit(struct expresswire_common_props *props, bool bit)
+{
+	if (bit) {
+		gpiod_set_value(props->ctrl_gpio, 0);
+		udelay(props->timing.short_bitset_us);
+		gpiod_set_value(props->ctrl_gpio, 1);
+		udelay(props->timing.long_bitset_us);
+	} else {
+		gpiod_set_value(props->ctrl_gpio, 0);
+		udelay(props->timing.long_bitset_us);
+		gpiod_set_value(props->ctrl_gpio, 1);
+		udelay(props->timing.short_bitset_us);
+	}
+}
+EXPORT_SYMBOL_NS_GPL(expresswire_set_bit, EXPRESSWIRE);
+
+void expresswire_write_u8(struct expresswire_common_props *props, u8 val)
+{
+	expresswire_start(props);
+	for (int i = 7; i >= 0; i--)
+		expresswire_set_bit(props, val & BIT(i));
+	expresswire_end(props);
+}
+EXPORT_SYMBOL_NS_GPL(expresswire_write_u8, EXPRESSWIRE);