Thread (3 messages) 3 messages, 1 author, 16d ago
COLD16d

[PATCH v5 2/2] backlight: Add SY7758 6-channel High Efficiency LED Driver support

From: Neil Armstrong <neil.armstrong@linaro.org>
Date: 2026-05-29 19:23:20
Also in: dri-devel, linux-devicetree, linux-leds, lkml
Subsystem: backlight class/subsystem, framebuffer layer, the rest · Maintainers: Lee Jones, Daniel Thompson, Jingoo Han, Helge Deller, Linus Torvalds

From: KancyJoe <redacted>

Implement support for the Silergy SY7758 6-channel High Efficiency LED
Driver used for backlight brightness control in the Ayaneo Pocket S2
dual-DSI panel.

Signed-off-by: KancyJoe <redacted>
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
---
 drivers/video/backlight/Kconfig  |   8 ++
 drivers/video/backlight/Makefile |   1 +
 drivers/video/backlight/sy7758.c | 259 +++++++++++++++++++++++++++++++++++++++
 3 files changed, 268 insertions(+)
diff --git a/drivers/video/backlight/Kconfig b/drivers/video/backlight/Kconfig
index a7a3fbaf7c29..a1f70a2bae99 100644
--- a/drivers/video/backlight/Kconfig
+++ b/drivers/video/backlight/Kconfig
@@ -207,6 +207,14 @@ config BACKLIGHT_KTZ8866
 		Say Y to enable the backlight driver for the Kinetic KTZ8866
 		found in Xiaomi Mi Pad 5 series.
 
+config BACKLIGHT_SY7758
+	tristate "Backlight Driver for Silergy SY7758"
+	depends on I2C
+	select REGMAP_I2C
+	help
+	  Say Y to enable the backlight driver for the Silergy SY7758
+	  backlight controller found in Ayaneo Pocket S2.
+
 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 794820a98ed4..39ef588b1cf2 100644
--- a/drivers/video/backlight/Makefile
+++ b/drivers/video/backlight/Makefile
@@ -56,6 +56,7 @@ obj-$(CONFIG_BACKLIGHT_PWM)		+= pwm_bl.o
 obj-$(CONFIG_BACKLIGHT_QCOM_WLED)	+= qcom-wled.o
 obj-$(CONFIG_BACKLIGHT_RT4831)		+= rt4831-backlight.o
 obj-$(CONFIG_BACKLIGHT_SAHARA)		+= kb3886_bl.o
+obj-$(CONFIG_BACKLIGHT_SY7758)		+= sy7758.o
 obj-$(CONFIG_BACKLIGHT_SKY81452)	+= sky81452-backlight.o
 obj-$(CONFIG_BACKLIGHT_TPS65217)	+= tps65217_bl.o
 obj-$(CONFIG_BACKLIGHT_WM831X)		+= wm831x_bl.o
diff --git a/drivers/video/backlight/sy7758.c b/drivers/video/backlight/sy7758.c
new file mode 100644
index 000000000000..786589cb8df9
--- /dev/null
+++ b/drivers/video/backlight/sy7758.c
@@ -0,0 +1,259 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Silergy SY7758 6-channel High Efficiency LED Driver
+ *
+ * Copyright (C) 2025 Kancy Joe <kancy2333@outlook.com>
+ * Copyright (C) 2026 Linaro Limited
+ * Author: Neil Armstrong <neil.armstrong@linaro.org>
+ */
+#include <linux/backlight.h>
+#include <linux/module.h>
+#include <linux/i2c.h>
+#include <linux/of.h>
+#include <linux/err.h>
+#include <linux/bits.h>
+#include <linux/delay.h>
+#include <linux/regmap.h>
+#include <linux/bitfield.h>
+#include <linux/gpio/consumer.h>
+#include <linux/regulator/consumer.h>
+
+#define DEFAULT_BRIGHTNESS	1024
+#define MAX_BRIGHTNESS		4080
+#define REG_MAX			0xAE
+
+/* Registers */
+#define REG_DEV_CTL		0x01
+#define REG_DEV_ID		0x03
+#define REG_BRT_12BIT_L		0x10
+#define REG_BRT_12BIT_H		0x11
+
+/* OTP memory */
+#define REG_OTP_CFG0		0xA0
+#define REG_OTP_CFG1		0xA1
+#define REG_OTP_CFG2		0xA2
+#define REG_OTP_CFG5		0xA5
+#define REG_OTP_CFG9		0xA9
+
+/* Fields */
+#define BIT_DEV_CTL_FAST	BIT(7)
+#define MSK_DEV_CTL_BRT_MODE	GENMASK(2, 1)
+#define BIT_DEV_CTL_BL_CTLB	BIT(0)
+
+#define MSK_BRT_12BIT_L		GENMASK(7, 0)
+#define MSK_BRT_12BIT_H		GENMASK(3, 0)
+
+#define MSK_CFG0_CURRENT_LOW	GENMASK(7, 0)
+
+#define BIT_CFG1_PDET_STDBY	BIT(7)
+#define MSK_CFG1_CURRENT_MAX	GENMASK(6, 4)
+#define MSK_CFG1_CURRENT_HIGH	GENMASK(3, 0)
+
+#define BIT_CFG2_UVLO_EN	BIT(5)
+#define BIT_CFG2_UVLO_TH	BIT(4)
+#define BIT_CFG2_BL_ON		BIT(3)
+#define BIT_CFG2_ISET_EN	BIT(2)
+#define BIT_CFG2_BST_ESET_EN	BIT(1)
+
+#define BIT_CFG5_PWM_DIRECT	BIT(7)
+#define MSK_CFG5_PS_MODE	GENMASK(6, 4)
+#define MSK_CFG5_PWM_FREQ	GENMASK(3, 0)
+
+#define MSK_CFG9_VBST_MAX	GENMASK(7, 5)
+#define BIT_CFG9_JUMP_EN	BIT(4)
+#define MSK_CFG9_JUMP_TH	GENMASK(3, 2)
+#define MSK_CFG9_JUMP_VOLTAGE	GENMASK(1, 0)
+
+struct sy7758 {
+	struct i2c_client *client;
+	struct regmap *regmap;
+	struct gpio_desc *gpio;
+	struct backlight_device *bl;
+};
+
+static const struct regmap_config sy7758_regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 8,
+	.max_register = REG_MAX,
+};
+
+static int sy7758_backlight_update_status(struct backlight_device *backlight_dev)
+{
+	struct sy7758 *sydev = bl_get_data(backlight_dev);
+	unsigned int brightness = backlight_get_brightness(backlight_dev);
+	int ret;
+
+	ret = regmap_write(sydev->regmap, REG_BRT_12BIT_L,
+			   FIELD_PREP(MSK_BRT_12BIT_L,
+				      brightness & 0xff));
+	if (ret)
+		return ret;
+
+	ret = regmap_write(sydev->regmap, REG_BRT_12BIT_H,
+			   FIELD_PREP(MSK_BRT_12BIT_H,
+				      (brightness >> 8) & 0xf));
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+static const struct backlight_ops sy7758_backlight_ops = {
+	.options = BL_CORE_SUSPENDRESUME,
+	.update_status = sy7758_backlight_update_status,
+};
+
+static int sy7758_init(struct sy7758 *sydev)
+{
+	int ret = 0;
+
+	ret = regmap_write(sydev->regmap, REG_DEV_CTL,
+			   BIT_DEV_CTL_FAST | BIT_DEV_CTL_BL_CTLB |
+			   FIELD_PREP(MSK_DEV_CTL_BRT_MODE, 2));
+	if (ret)
+		return ret;
+
+	ret = regmap_write(sydev->regmap, REG_BRT_12BIT_L,
+			   FIELD_PREP(MSK_BRT_12BIT_L,
+				      DEFAULT_BRIGHTNESS & 0xff));
+	if (ret)
+		return ret;
+
+	ret = regmap_write(sydev->regmap, REG_BRT_12BIT_H,
+			   FIELD_PREP(MSK_BRT_12BIT_H,
+				      (DEFAULT_BRIGHTNESS >> 8)));
+	if (ret)
+		return ret;
+
+	ret = regmap_write(sydev->regmap, REG_OTP_CFG5,
+			   FIELD_PREP(MSK_CFG5_PS_MODE, 6) |
+			   FIELD_PREP(MSK_CFG5_PWM_FREQ, 4));
+	if (ret)
+		return ret;
+
+	ret = regmap_write(sydev->regmap, REG_OTP_CFG0,
+			   FIELD_PREP(MSK_CFG0_CURRENT_LOW, 85));
+	if (ret)
+		return ret;
+
+	ret = regmap_write(sydev->regmap, REG_OTP_CFG1,
+			   BIT_CFG1_PDET_STDBY |
+			   FIELD_PREP(MSK_CFG1_CURRENT_MAX, 1) |
+			   FIELD_PREP(MSK_CFG1_CURRENT_HIGH, 10));
+	if (ret)
+		return ret;
+
+	ret = regmap_write(sydev->regmap, REG_OTP_CFG9,
+			   FIELD_PREP(MSK_CFG9_VBST_MAX, 4));
+	if (ret)
+		return ret;
+
+	ret = regmap_write(sydev->regmap, REG_OTP_CFG2,
+			   BIT_CFG2_BL_ON | BIT_CFG2_UVLO_EN);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+static int sy7758_probe(struct i2c_client *client)
+{
+	struct backlight_properties props = { };
+	struct device *dev = &client->dev;
+	struct sy7758 *sydev;
+	unsigned int dev_id;
+	int ret;
+
+	sydev = devm_kzalloc(dev, sizeof(*sydev), GFP_KERNEL);
+	if (!sydev)
+		return -ENOMEM;
+
+	i2c_set_clientdata(client, sydev);
+
+	/* Initialize regmap */
+	sydev->client = client;
+	sydev->regmap = devm_regmap_init_i2c(client, &sy7758_regmap_config);
+	if (IS_ERR(sydev->regmap))
+		return dev_err_probe(dev, PTR_ERR(sydev->regmap),
+				     "failed to init regmap\n");
+
+	/* Get and enable regulator */
+	ret = devm_regulator_get_enable(dev, "vdd");
+	if (ret)
+		return dev_err_probe(dev, ret, "failed to get regulator\n");
+
+	fsleep(100);
+
+	/* Get enable GPIO and set to high */
+	sydev->gpio = devm_gpiod_get(dev, "enable", GPIOD_OUT_HIGH);
+	if (IS_ERR(sydev->gpio))
+		return dev_err_probe(dev, PTR_ERR(sydev->gpio),
+				     "failed to get enable GPIO\n");
+
+	/* Let some time for HW to settle */
+	fsleep(10000);
+
+	/* try read and check device id */
+	ret = regmap_read(sydev->regmap, REG_DEV_ID, &dev_id);
+	if (ret < 0)
+		return dev_err_probe(dev, ret, "failed to read device id\n");
+	if (dev_id != 0x63) {
+		dev_err(dev, "unexpected device id: 0x%02x\n", dev_id);
+		return -ENODEV;
+	}
+
+	/* Initialize and set default brightness */
+	ret = sy7758_init(sydev);
+	if (ret)
+		return ret;
+
+	props.type = BACKLIGHT_RAW;
+	props.max_brightness = MAX_BRIGHTNESS;
+	props.brightness = DEFAULT_BRIGHTNESS;
+	props.scale = BACKLIGHT_SCALE_LINEAR;
+
+	sydev->bl = devm_backlight_device_register(dev, "sy7758-backlight",
+						   dev, sydev, &sy7758_backlight_ops,
+						   &props);
+	if (IS_ERR(sydev->bl))
+		return dev_err_probe(dev, PTR_ERR(sydev->bl),
+				     "failed to register backlight device\n");
+
+	return backlight_update_status(sydev->bl);
+}
+
+static void sy7758_remove(struct i2c_client *client)
+{
+	struct sy7758 *sydev = i2c_get_clientdata(client);
+
+	backlight_disable(sydev->bl);
+}
+
+static const struct i2c_device_id sy7758_ids[] = {
+	{ "sy7758" },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, sy7758_ids);
+
+static const struct of_device_id sy7758_match_table[] = {
+	{ .compatible = "silergy,sy7758", },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, sy7758_match_table);
+
+static struct i2c_driver sy7758_driver = {
+	.driver = {
+		.name = "sy7758",
+		.of_match_table = sy7758_match_table,
+	},
+	.probe = sy7758_probe,
+	.remove = sy7758_remove,
+	.id_table = sy7758_ids,
+};
+
+module_i2c_driver(sy7758_driver);
+
+MODULE_DESCRIPTION("Silergy SY7758 Backlight Driver");
+MODULE_AUTHOR("Kancy Joe <kancy2333@outlook.com>");
+MODULE_AUTHOR("Neil Armstrong <neil.armstrong@linaro.org>");
+MODULE_LICENSE("GPL");
-- 
2.34.1
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