Merge tag 'backlight-next-6.20' of git://git.kernel.org/pub/scm/linux/kernel/git/lee/backlight

Pull backlight updates from Lee Jones:
 "New Support & Features:

   - Add a new driver for the Congatec Board Controller (CGBC)
     backlight, providing brightness control via the board controller's
     PWM interface

  Improvements & Fixes:

   - Resolve build failures in the Awinic AW99706 driver by switching to
     the correct GPIO consumer header

   - Extend the Qualcomm WLED driver to support the specific
     over-voltage protection (OVP) values required for the PMI8994 and
     PMI8950 variants

  Device Tree Bindings Updates:

   - Document the device-specific over-voltage protection (OVP)
     millivolt ranges and default values for Qualcomm PMI8994 and
     PMI8950 WLED controllers"

* tag 'backlight-next-6.20' of git://git.kernel.org/pub/scm/linux/kernel/git/lee/backlight:
  backlight: qcom-wled: Change PM8950 WLED configurations
  dt-bindings: backlight: qcom-wled: Document ovp values for PMI8950
  backlight: qcom-wled: Support ovp values for PMI8994
  dt-bindings: backlight: qcom-wled: Document ovp values for PMI8994
  backlight: aw99706: Fix build errors caused by wrong gpio header
  backlight: Add Congatec Board Controller (CGBC) backlight support

5 files changed, 233 insertions, 3 deletions

diff --git a/drivers/video/backlight/Kconfig b/drivers/video/backlight/Kconfig
index a1422ddd1c22..a7a3fbaf7c29 100644
--- a/drivers/video/backlight/Kconfig
+++ b/drivers/video/backlight/Kconfig
@@ -258,6 +258,17 @@ config BACKLIGHT_PWM
 	  If you have a LCD backlight adjustable by PWM, say Y to enable
 	  this driver.
 
+config BACKLIGHT_CGBC
+	tristate "Congatec Board Controller (CGBC) backlight support"
+	depends on MFD_CGBC && X86
+	help
+	  Say Y here to enable support for LCD backlight control on Congatec
+	  x86-based boards via the CGBC (Congatec Board Controller).
+
+	  This driver provides backlight brightness control through the Linux
+	  backlight subsystem. It communicates with the board controller to
+	  adjust LCD backlight using PWM signals.
+
 config BACKLIGHT_DA903X
 	tristate "Backlight Driver for DA9030/DA9034 using WLED"
 	depends on PMIC_DA903X
diff --git a/drivers/video/backlight/Makefile b/drivers/video/backlight/Makefile
index a5d62b018102..794820a98ed4 100644
--- a/drivers/video/backlight/Makefile
+++ b/drivers/video/backlight/Makefile
@@ -27,6 +27,7 @@ obj-$(CONFIG_BACKLIGHT_APPLE_DWI)	+= apple_dwi_bl.o
 obj-$(CONFIG_BACKLIGHT_AS3711)		+= as3711_bl.o
 obj-$(CONFIG_BACKLIGHT_AW99706)		+= aw99706.o
 obj-$(CONFIG_BACKLIGHT_BD6107)		+= bd6107.o
+obj-$(CONFIG_BACKLIGHT_CGBC)		+= cgbc_bl.o
 obj-$(CONFIG_BACKLIGHT_CLASS_DEVICE)	+= backlight.o
 obj-$(CONFIG_BACKLIGHT_DA903X)		+= da903x_bl.o
 obj-$(CONFIG_BACKLIGHT_DA9052)		+= da9052_bl.o
diff --git a/drivers/video/backlight/aw99706.c b/drivers/video/backlight/aw99706.c
index df5b23b2f753..938f352aaab7 100644
--- a/drivers/video/backlight/aw99706.c
+++ b/drivers/video/backlight/aw99706.c
@@ -12,7 +12,7 @@
 #include <linux/backlight.h>
 #include <linux/bitfield.h>
 #include <linux/delay.h>
-#include <linux/gpio.h>
+#include <linux/gpio/consumer.h>
 #include <linux/i2c.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
diff --git a/drivers/video/backlight/cgbc_bl.c b/drivers/video/backlight/cgbc_bl.c
new file mode 100644
index 000000000000..ab27e14338a8
--- /dev/null
+++ b/drivers/video/backlight/cgbc_bl.c
@@ -0,0 +1,180 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Congatec Board Controller (CGBC) Backlight Driver
+ *
+ * This driver provides backlight control for LCD displays connected to
+ * Congatec boards via the CGBC (Congatec Board Controller). It integrates
+ * with the Linux backlight subsystem and communicates with hardware through
+ * the cgbc-core module.
+ *
+ * Copyright (C) 2025 Novatron Oy
+ *
+ * Author: Petri Karhula <petri.karhula@novatron.fi>
+ */
+
+#include <linux/backlight.h>
+#include <linux/bitfield.h>
+#include <linux/bits.h>
+#include <linux/mfd/cgbc.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+
+#define BLT_PWM_DUTY_MASK          GENMASK(6, 0)
+
+/* CGBC command for PWM brightness control*/
+#define CGBC_CMD_BLT0_PWM          0x75
+
+#define CGBC_BL_MAX_BRIGHTNESS     100
+
+/**
+ * CGBC backlight driver data
+ * @dev: Pointer to the platform device
+ * @cgbc: Pointer to the parent CGBC device data
+ * @current_brightness: Current brightness level (0-100)
+ */
+struct cgbc_bl_data {
+	struct device *dev;
+	struct cgbc_device_data *cgbc;
+	unsigned int current_brightness;
+};
+
+static int cgbc_bl_read_brightness(struct cgbc_bl_data *bl_data)
+{
+	u8 cmd_buf[4] = { CGBC_CMD_BLT0_PWM };
+	u8 reply_buf[3];
+	int ret;
+
+	ret = cgbc_command(bl_data->cgbc, cmd_buf, sizeof(cmd_buf),
+			   reply_buf, sizeof(reply_buf), NULL);
+	if (ret < 0)
+		return ret;
+
+	/*
+	 * Get only PWM duty factor percentage,
+	 * ignore polarity inversion bit (bit 7)
+	 */
+	bl_data->current_brightness = FIELD_GET(BLT_PWM_DUTY_MASK, reply_buf[0]);
+
+	return 0;
+}
+
+static int cgbc_bl_update_status(struct backlight_device *bl)
+{
+	struct cgbc_bl_data *bl_data = bl_get_data(bl);
+	u8 cmd_buf[4] = { CGBC_CMD_BLT0_PWM };
+	u8 reply_buf[3];
+	u8 brightness;
+	int ret;
+
+	brightness = backlight_get_brightness(bl);
+
+	if (brightness != bl_data->current_brightness) {
+		/* Read the current values */
+		ret = cgbc_command(bl_data->cgbc, cmd_buf, sizeof(cmd_buf), reply_buf,
+				   sizeof(reply_buf), NULL);
+		if (ret < 0) {
+			dev_err(bl_data->dev, "Failed to read PWM settings: %d\n", ret);
+			return ret;
+		}
+
+		/*
+		 * Prepare command buffer for writing new settings. Only 2nd byte is changed
+		 * to set new brightness (PWM duty cycle %). Other values (polarity, frequency)
+		 * are preserved from the read values.
+		 */
+		cmd_buf[1] = (reply_buf[0] & ~BLT_PWM_DUTY_MASK) |
+			FIELD_PREP(BLT_PWM_DUTY_MASK, brightness);
+		cmd_buf[2] = reply_buf[1];
+		cmd_buf[3] = reply_buf[2];
+
+		ret = cgbc_command(bl_data->cgbc, cmd_buf, sizeof(cmd_buf), reply_buf,
+				   sizeof(reply_buf), NULL);
+		if (ret < 0) {
+			dev_err(bl_data->dev, "Failed to set brightness: %d\n", ret);
+			return ret;
+		}
+
+		bl_data->current_brightness = reply_buf[0] & BLT_PWM_DUTY_MASK;
+
+		/* Verify the setting was applied correctly */
+		if (bl_data->current_brightness != brightness) {
+			dev_err(bl_data->dev,
+				"Brightness setting verification failed (got %u, expected %u)\n",
+				bl_data->current_brightness, (unsigned int)brightness);
+			return -EIO;
+		}
+	}
+
+	return 0;
+}
+
+static int cgbc_bl_get_brightness(struct backlight_device *bl)
+{
+	struct cgbc_bl_data *bl_data = bl_get_data(bl);
+	int ret;
+
+	ret = cgbc_bl_read_brightness(bl_data);
+	if (ret < 0) {
+		dev_err(bl_data->dev, "Failed to read brightness: %d\n", ret);
+		return ret;
+	}
+
+	return bl_data->current_brightness;
+}
+
+static const struct backlight_ops cgbc_bl_ops = {
+	.options = BL_CORE_SUSPENDRESUME,
+	.update_status = cgbc_bl_update_status,
+	.get_brightness = cgbc_bl_get_brightness,
+};
+
+static int cgbc_bl_probe(struct platform_device *pdev)
+{
+	struct cgbc_device_data *cgbc = dev_get_drvdata(pdev->dev.parent);
+	struct backlight_properties props = { };
+	struct backlight_device *bl_dev;
+	struct cgbc_bl_data *bl_data;
+	int ret;
+
+	bl_data = devm_kzalloc(&pdev->dev, sizeof(*bl_data), GFP_KERNEL);
+	if (!bl_data)
+		return -ENOMEM;
+
+	bl_data->dev = &pdev->dev;
+	bl_data->cgbc = cgbc;
+
+	ret = cgbc_bl_read_brightness(bl_data);
+	if (ret < 0)
+		return dev_err_probe(&pdev->dev, ret,
+				     "Failed to read initial brightness\n");
+
+	props.type = BACKLIGHT_PLATFORM;
+	props.max_brightness = CGBC_BL_MAX_BRIGHTNESS;
+	props.brightness = bl_data->current_brightness;
+	props.scale = BACKLIGHT_SCALE_LINEAR;
+
+	bl_dev = devm_backlight_device_register(&pdev->dev, "cgbc-backlight",
+						&pdev->dev, bl_data,
+						&cgbc_bl_ops, &props);
+	if (IS_ERR(bl_dev))
+		return dev_err_probe(&pdev->dev, PTR_ERR(bl_dev),
+			     "Failed to register backlight device\n");
+
+	platform_set_drvdata(pdev, bl_data);
+
+	return 0;
+}
+
+static struct platform_driver cgbc_bl_driver = {
+	.driver = {
+		.name = "cgbc-backlight",
+	},
+	.probe = cgbc_bl_probe,
+};
+
+module_platform_driver(cgbc_bl_driver);
+
+MODULE_AUTHOR("Petri Karhula <petri.karhula@novatron.fi>");
+MODULE_DESCRIPTION("Congatec Board Controller (CGBC) Backlight Driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:cgbc-backlight");
diff --git a/drivers/video/backlight/qcom-wled.c b/drivers/video/backlight/qcom-wled.c
index a63bb42c8f8b..8054e4787725 100644
--- a/drivers/video/backlight/qcom-wled.c
+++ b/drivers/video/backlight/qcom-wled.c
@@ -1244,6 +1244,15 @@ static const struct wled_var_cfg wled4_ovp_cfg = {
 	.size = ARRAY_SIZE(wled4_ovp_values),
 };
 
+static const u32 pmi8994_wled_ovp_values[] = {
+	31000, 29500, 19400, 17800,
+};
+
+static const struct wled_var_cfg pmi8994_wled_ovp_cfg = {
+	.values = pmi8994_wled_ovp_values,
+	.size = ARRAY_SIZE(pmi8994_wled_ovp_values),
+};
+
 static inline u32 wled5_ovp_values_fn(u32 idx)
 {
 	/*
@@ -1357,6 +1366,29 @@ static int wled_configure(struct wled *wled)
 		},
 	};
 
+	const struct wled_u32_opts pmi8994_wled_opts[] = {
+		{
+			.name = "qcom,current-boost-limit",
+			.val_ptr = &cfg->boost_i_limit,
+			.cfg = &wled4_boost_i_limit_cfg,
+		},
+		{
+			.name = "qcom,current-limit-microamp",
+			.val_ptr = &cfg->string_i_limit,
+			.cfg = &wled4_string_i_limit_cfg,
+		},
+		{
+			.name = "qcom,ovp-millivolt",
+			.val_ptr = &cfg->ovp,
+			.cfg = &pmi8994_wled_ovp_cfg,
+		},
+		{
+			.name = "qcom,switching-freq",
+			.val_ptr = &cfg->switch_freq,
+			.cfg = &wled3_switch_freq_cfg,
+		},
+	};
+
 	const struct wled_u32_opts wled5_opts[] = {
 		{
 			.name = "qcom,current-boost-limit",
@@ -1423,8 +1455,14 @@ static int wled_configure(struct wled *wled)
 		break;
 
 	case 4:
-		u32_opts = wled4_opts;
-		size = ARRAY_SIZE(wled4_opts);
+		if (of_device_is_compatible(dev->of_node, "qcom,pmi8950-wled") ||
+		    of_device_is_compatible(dev->of_node, "qcom,pmi8994-wled")) {
+			u32_opts = pmi8994_wled_opts;
+			size = ARRAY_SIZE(pmi8994_wled_opts);
+		} else {
+			u32_opts = wled4_opts;
+			size = ARRAY_SIZE(wled4_opts);
+		}
 		*cfg = wled4_config_defaults;
 		wled->wled_set_brightness = wled4_set_brightness;
 		wled->wled_sync_toggle = wled3_sync_toggle;