@@ -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 regulators */
+ ret = devm_regulator_get_enable(dev, "vddio");
+ 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");