diff --git a/Documentation/devicetree/bindings/leds/backlight/common.yaml b/Documentation/devicetree/bindings/leds/backlight/common.yaml
new file mode 100644
index 0000000000000000000000000000000000000000..4e7e95e331a57dc26dd598c87eb8a8477b2fe062
--- /dev/null
+++ b/Documentation/devicetree/bindings/leds/backlight/common.yaml
@@ -0,0 +1,34 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/leds/backlight/common.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Common backlight properties
+
+maintainers:
+ - Lee Jones <lee.jones@linaro.org>
+ - Daniel Thompson <daniel.thompson@linaro.org>
+ - Jingoo Han <jingoohan1@gmail.com>
+
+description:
+ Backlight devices provide backlight for different types of graphical
+ displays. They are typically but not necessarily implemented using a white
+ LED powered by a boost converter.
+
+properties:
+ default-brightness:
+ description:
+ The default brightness that should be applied to the LED by the operating
+ system on start-up. The brightness should not exceed the brightness the
+ LED can provide.
+ $ref: /schemas/types.yaml#definitions/uint32
+
+ max-brightness:
+ description:
+ Normally the maximum brightness is determined by the hardware and this
+ property is not required. This property is used to put a software limit
+ on the brightness apart from what the driver says, as it could happen
+ that a LED can be made so bright that it gets damaged or causes damage
+ due to restrictions in a specific system, such as mounting conditions.
+ $ref: /schemas/types.yaml#definitions/uint32
diff --git a/Documentation/devicetree/bindings/leds/backlight/kinetic,ktd253.yaml b/Documentation/devicetree/bindings/leds/backlight/kinetic,ktd253.yaml
new file mode 100644
index 0000000000000000000000000000000000000000..7a6ec1f8c0f35a655facc0208b847728a7eaeabc
--- /dev/null
+++ b/Documentation/devicetree/bindings/leds/backlight/kinetic,ktd253.yaml
@@ -0,0 +1,46 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/leds/backlight/kinetic,ktd253.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Kinetic Technologies KTD253 one-wire backlight
+
+maintainers:
+ - Linus Walleij <linus.walleij@linaro.org>
+
+description: |
+ The Kinetic Technologies KTD253 is a white LED backlight that is
+ controlled by a single GPIO line. If you just turn on the backlight
+ it goes to maximum backlight then you can set the level of backlight
+ using pulses on the enable wire. This is sometimes referred to as
+ "expresswire".
+
+allOf:
+ - $ref: common.yaml#
+
+properties:
+ compatible:
+ const: kinetic,ktd253
+
+ enable-gpios:
+ description: GPIO to use to enable/disable and dim the backlight.
+ maxItems: 1
+
+ default-brightness: true
+ max-brightness: true
+
+required:
+ - compatible
+ - enable-gpios
+
+additionalProperties: false
+
+examples:
+ - |
+ #include <dt-bindings/gpio/gpio.h>
+ backlight {
+ compatible = "kinetic,ktd253";
+ enable-gpios = <&gpio2 5 GPIO_ACTIVE_HIGH>;
+ default-brightness = <13>;
+ };
diff --git a/MAINTAINERS b/MAINTAINERS
index 608b726f0fe61a69aede2eca65c1ba12482cd512..385bd1258bf827813d9dc399260ce07568e7a068 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -9760,6 +9760,12 @@ F: Documentation/admin-guide/auxdisplay/ks0108.rst
F: drivers/auxdisplay/ks0108.c
F: include/linux/ks0108.h
+KTD253 BACKLIGHT DRIVER
+M: Linus Walleij <linus.walleij@linaro.org>
+S: Maintained
+F: Documentation/devicetree/bindings/leds/backlight/kinetic,ktd253.yaml
+F: drivers/video/backlight/ktd253-backlight.c
+
L3MDEV
M: David Ahern <dsahern@kernel.org>
L: netdev@vger.kernel.org
diff --git a/drivers/video/backlight/Kconfig b/drivers/video/backlight/Kconfig
index 87f9fc238d28a69fddd2a7bce6e1dfea29aa3269..d83c87b902c16d40019e2daf6c7a6577f6baab55 100644
--- a/drivers/video/backlight/Kconfig
+++ b/drivers/video/backlight/Kconfig
@@ -182,6 +182,14 @@ config BACKLIGHT_IPAQ_MICRO
computers. Say yes if you have one of the h3100/h3600/h3700
machines.
+config BACKLIGHT_KTD253
+ tristate "Backlight Driver for Kinetic KTD253"
+ depends on GPIOLIB || COMPILE_TEST
+ help
+ Say y to enabled the backlight driver for the Kinetic KTD253
+ which is a 1-wire GPIO-controlled backlight found in some mobile
+ phones.
+
config BACKLIGHT_LM3533
tristate "Backlight Driver for LM3533"
depends on MFD_LM3533
diff --git a/drivers/video/backlight/Makefile b/drivers/video/backlight/Makefile
index 13463b99f1f94823ca83f3963e816cd6b35829b5..685f3f1ca4df64e1e12dd58d06f97c2d6e1b9bc3 100644
--- a/drivers/video/backlight/Makefile
+++ b/drivers/video/backlight/Makefile
@@ -35,6 +35,7 @@ obj-$(CONFIG_BACKLIGHT_GPIO) += gpio_backlight.o
obj-$(CONFIG_BACKLIGHT_HP680) += hp680_bl.o
obj-$(CONFIG_BACKLIGHT_HP700) += jornada720_bl.o
obj-$(CONFIG_BACKLIGHT_IPAQ_MICRO) += ipaq_micro_bl.o
+obj-$(CONFIG_BACKLIGHT_KTD253) += ktd253-backlight.o
obj-$(CONFIG_BACKLIGHT_LM3533) += lm3533_bl.o
obj-$(CONFIG_BACKLIGHT_LM3630A) += lm3630a_bl.o
obj-$(CONFIG_BACKLIGHT_LM3639) += lm3639_bl.o
diff --git a/drivers/video/backlight/ktd253-backlight.c b/drivers/video/backlight/ktd253-backlight.c
new file mode 100644
index 0000000000000000000000000000000000000000..e3fee3f1f58280cf6cc542f6abf436ef696fe5e7
--- /dev/null
+++ b/drivers/video/backlight/ktd253-backlight.c
@@ -0,0 +1,198 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Backlight driver for the Kinetic KTD253
+ * Based on code and know-how from the Samsung GT-S7710
+ * Gareth Phillips <gareth.phillips@samsung.com>
+ */
+#include <linux/backlight.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/fb.h>
+#include <linux/gpio/consumer.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/limits.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/property.h>
+#include <linux/slab.h>
+
+/* Current ratio is n/32 from 1/32 to 32/32 */
+#define KTD253_MIN_RATIO 1
+#define KTD253_MAX_RATIO 32
+#define KTD253_DEFAULT_RATIO 13
+
+#define KTD253_T_LOW_NS (200 + 10) /* Additional 10ns as safety factor */
+#define KTD253_T_HIGH_NS (200 + 10) /* Additional 10ns as safety factor */
+#define KTD253_T_OFF_MS 3
+
+struct ktd253_backlight {
+ struct device *dev;
+ struct backlight_device *bl;
+ struct gpio_desc *gpiod;
+ u16 ratio;
+};
+
+static int ktd253_backlight_update_status(struct backlight_device *bl)
+{
+ struct ktd253_backlight *ktd253 = bl_get_data(bl);
+ int brightness = backlight_get_brightness(bl);
+ u16 target_ratio;
+ u16 current_ratio = ktd253->ratio;
+ unsigned long flags;
+
+ dev_dbg(ktd253->dev, "new brightness/ratio: %d/32\n", brightness);
+
+ target_ratio = brightness;
+
+ if (target_ratio == current_ratio)
+ /* This is already right */
+ return 0;
+
+ if (target_ratio == 0) {
+ gpiod_set_value_cansleep(ktd253->gpiod, 0);
+ /*
+ * We need to keep the GPIO low for at least this long
+ * to actually switch the KTD253 off.
+ */
+ msleep(KTD253_T_OFF_MS);
+ ktd253->ratio = 0;
+ return 0;
+ }
+
+ if (current_ratio == 0) {
+ gpiod_set_value_cansleep(ktd253->gpiod, 1);
+ ndelay(KTD253_T_HIGH_NS);
+ /* We always fall back to this when we power on */
+ current_ratio = KTD253_MAX_RATIO;
+ }
+
+ /*
+ * WARNING:
+ * The loop to set the correct current level is performed
+ * with interrupts disabled as it is timing critical.
+ * The maximum number of cycles of the loop is 32
+ * so the time taken will be (T_LOW_NS + T_HIGH_NS + loop_time) * 32,
+ */
+ local_irq_save(flags);
+ while (current_ratio != target_ratio) {
+ /*
+ * These GPIO operations absolutely can NOT sleep so no
+ * _cansleep suffixes, and no using GPIO expanders on
+ * slow buses for this!
+ */
+ gpiod_set_value(ktd253->gpiod, 0);
+ ndelay(KTD253_T_LOW_NS);
+ gpiod_set_value(ktd253->gpiod, 1);
+ ndelay(KTD253_T_HIGH_NS);
+ /* After 1/32 we loop back to 32/32 */
+ if (current_ratio == KTD253_MIN_RATIO)
+ current_ratio = KTD253_MAX_RATIO;
+ else
+ current_ratio--;
+ }
+ local_irq_restore(flags);
+ ktd253->ratio = current_ratio;
+
+ dev_dbg(ktd253->dev, "new ratio set to %d/32\n", target_ratio);
+
+ return 0;
+}
+
+static const struct backlight_ops ktd253_backlight_ops = {
+ .options = BL_CORE_SUSPENDRESUME,
+ .update_status = ktd253_backlight_update_status,
+};
+
+static int ktd253_backlight_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct backlight_device *bl;
+ struct ktd253_backlight *ktd253;
+ u32 max_brightness;
+ u32 brightness;
+ int ret;
+
+ ktd253 = devm_kzalloc(dev, sizeof(*ktd253), GFP_KERNEL);
+ if (!ktd253)
+ return -ENOMEM;
+ ktd253->dev = dev;
+
+ ret = device_property_read_u32(dev, "max-brightness", &max_brightness);
+ if (ret)
+ max_brightness = KTD253_MAX_RATIO;
+ if (max_brightness > KTD253_MAX_RATIO) {
+ /* Clamp brightness to hardware max */
+ dev_err(dev, "illegal max brightness specified\n");
+ max_brightness = KTD253_MAX_RATIO;
+ }
+
+ ret = device_property_read_u32(dev, "default-brightness", &brightness);
+ if (ret)
+ brightness = KTD253_DEFAULT_RATIO;
+ if (brightness > max_brightness) {
+ /* Clamp default brightness to max brightness */
+ dev_err(dev, "default brightness exceeds max brightness\n");
+ brightness = max_brightness;
+ }
+
+ if (brightness)
+ /* This will be the default ratio when the KTD253 is enabled */
+ ktd253->ratio = KTD253_MAX_RATIO;
+ else
+ ktd253->ratio = 0;
+
+ ktd253->gpiod = devm_gpiod_get(dev, "enable",
+ brightness ? GPIOD_OUT_HIGH :
+ GPIOD_OUT_LOW);
+ if (IS_ERR(ktd253->gpiod)) {
+ ret = PTR_ERR(ktd253->gpiod);
+ if (ret != -EPROBE_DEFER)
+ dev_err(dev, "gpio line missing or invalid.\n");
+ return ret;
+ }
+ gpiod_set_consumer_name(ktd253->gpiod, dev_name(dev));
+
+ bl = devm_backlight_device_register(dev, dev_name(dev), dev, ktd253,
+ &ktd253_backlight_ops, NULL);
+ if (IS_ERR(bl)) {
+ dev_err(dev, "failed to register backlight\n");
+ return PTR_ERR(bl);
+ }
+ bl->props.max_brightness = max_brightness;
+ /* When we just enable the GPIO line we set max brightness */
+ if (brightness) {
+ bl->props.brightness = brightness;
+ bl->props.power = FB_BLANK_UNBLANK;
+ } else {
+ bl->props.brightness = 0;
+ bl->props.power = FB_BLANK_POWERDOWN;
+ }
+
+ ktd253->bl = bl;
+ platform_set_drvdata(pdev, bl);
+ backlight_update_status(bl);
+
+ return 0;
+}
+
+static const struct of_device_id ktd253_backlight_of_match[] = {
+ { .compatible = "kinetic,ktd253" },
+ { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, ktd253_backlight_of_match);
+
+static struct platform_driver ktd253_backlight_driver = {
+ .driver = {
+ .name = "ktd253-backlight",
+ .of_match_table = ktd253_backlight_of_match,
+ },
+ .probe = ktd253_backlight_probe,
+};
+module_platform_driver(ktd253_backlight_driver);
+
+MODULE_AUTHOR("Linus Walleij <linus.walleij@linaro.org>");
+MODULE_DESCRIPTION("Kinetic KTD253 Backlight Driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:ktd253-backlight");
diff --git a/drivers/video/backlight/sky81452-backlight.c b/drivers/video/backlight/sky81452-backlight.c
index 0ce18158500807b79232099ec63ceaf1f0f43057..8268ac43d54f78366d4487eb2798420e897d376c 100644
--- a/drivers/video/backlight/sky81452-backlight.c
+++ b/drivers/video/backlight/sky81452-backlight.c
@@ -217,6 +217,7 @@ static struct sky81452_bl_platform_data *sky81452_bl_parse_dt(
num_entry);
if (ret < 0) {
dev_err(dev, "led-sources node is invalid.\n");
+ of_node_put(np);
return ERR_PTR(-EINVAL);
}
diff --git a/drivers/video/backlight/tosa_bl.c b/drivers/video/backlight/tosa_bl.c
index cff5e96fd9884224b610086143ed5ee03c1b54b4..6df6fcd132e36794094c117fe496e9da32b0ae7b 100644
--- a/drivers/video/backlight/tosa_bl.c
+++ b/drivers/video/backlight/tosa_bl.c
@@ -11,7 +11,7 @@
#include <linux/device.h>
#include <linux/spi/spi.h>
#include <linux/i2c.h>
-#include <linux/gpio.h>
+#include <linux/gpio/consumer.h>
#include <linux/fb.h>
#include <linux/backlight.h>
#include <linux/slab.h>
diff --git a/drivers/video/backlight/tosa_lcd.c b/drivers/video/backlight/tosa_lcd.c
index 113116d3585c6b9cb83e57f69e3c410704d01bc2..38765544345b8d76f07aacfd6038f1855ad082e2 100644
--- a/drivers/video/backlight/tosa_lcd.c
+++ b/drivers/video/backlight/tosa_lcd.c
@@ -12,7 +12,7 @@
#include <linux/spi/spi.h>
#include <linux/i2c.h>
#include <linux/slab.h>
-#include <linux/gpio.h>
+#include <linux/gpio/consumer.h>
#include <linux/delay.h>
#include <linux/lcd.h>
#include <linux/fb.h>