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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * Backlight driver for the Kinetic KTZ88664 *5 * Copyright (C) 2022, 2023 Jianhua Lu <lujianhua000@gmail.com>6 */7 8#include <linux/backlight.h>9#include <linux/err.h>10#include <linux/gpio/consumer.h>11#include <linux/i2c.h>12#include <linux/module.h>13#include <linux/of.h>14#include <linux/regmap.h>15 16#define DEFAULT_BRIGHTNESS 150017#define MAX_BRIGHTNESS 204718#define REG_MAX 0x1519 20/* reg */21#define DEVICE_ID 0x0122#define BL_CFG1 0x0223#define BL_CFG2 0x0324#define BL_BRT_LSB 0x0425#define BL_BRT_MSB 0x0526#define BL_EN 0x0827#define LCD_BIAS_CFG1 0x0928#define LCD_BIAS_CFG2 0x0A29#define LCD_BIAS_CFG3 0x0B30#define LCD_BOOST_CFG 0x0C31#define OUTP_CFG 0x0D32#define OUTN_CFG 0x0E33#define FLAG 0x0F34#define BL_OPTION1 0x1035#define BL_OPTION2 0x1136#define PWM2DIG_LSBs 0x1237#define PWM2DIG_MSBs 0x1338#define BL_DIMMING 0x1439#define PWM_RAMP_TIME 0x1540 41/* definition */42#define BL_EN_BIT BIT(6)43#define LCD_BIAS_EN 0x9F44#define PWM_HYST 0x545 46struct ktz8866 {47 struct i2c_client *client;48 struct regmap *regmap;49 bool led_on;50 struct gpio_desc *enable_gpio;51};52 53static const struct regmap_config ktz8866_regmap_config = {54 .reg_bits = 8,55 .val_bits = 8,56 .max_register = REG_MAX,57};58 59static int ktz8866_write(struct ktz8866 *ktz, unsigned int reg,60 unsigned int val)61{62 return regmap_write(ktz->regmap, reg, val);63}64 65static int ktz8866_update_bits(struct ktz8866 *ktz, unsigned int reg,66 unsigned int mask, unsigned int val)67{68 return regmap_update_bits(ktz->regmap, reg, mask, val);69}70 71static int ktz8866_backlight_update_status(struct backlight_device *backlight_dev)72{73 struct ktz8866 *ktz = bl_get_data(backlight_dev);74 unsigned int brightness = backlight_get_brightness(backlight_dev);75 76 if (!ktz->led_on && brightness > 0) {77 ktz8866_update_bits(ktz, BL_EN, BL_EN_BIT, BL_EN_BIT);78 ktz->led_on = true;79 } else if (brightness == 0) {80 ktz8866_update_bits(ktz, BL_EN, BL_EN_BIT, 0);81 ktz->led_on = false;82 }83 84 /* Set brightness */85 ktz8866_write(ktz, BL_BRT_LSB, brightness & 0x7);86 ktz8866_write(ktz, BL_BRT_MSB, (brightness >> 3) & 0xFF);87 88 return 0;89}90 91static const struct backlight_ops ktz8866_backlight_ops = {92 .options = BL_CORE_SUSPENDRESUME,93 .update_status = ktz8866_backlight_update_status,94};95 96static void ktz8866_init(struct ktz8866 *ktz)97{98 unsigned int val = 0;99 100 if (!of_property_read_u32(ktz->client->dev.of_node, "current-num-sinks", &val))101 ktz8866_write(ktz, BL_EN, BIT(val) - 1);102 else103 /* Enable all 6 current sinks if the number of current sinks isn't specified. */104 ktz8866_write(ktz, BL_EN, BIT(6) - 1);105 106 if (!of_property_read_u32(ktz->client->dev.of_node, "kinetic,current-ramp-delay-ms", &val)) {107 if (val <= 128)108 ktz8866_write(ktz, BL_CFG2, BIT(7) | (ilog2(val) << 3) | PWM_HYST);109 else110 ktz8866_write(ktz, BL_CFG2, BIT(7) | ((5 + val / 64) << 3) | PWM_HYST);111 }112 113 if (!of_property_read_u32(ktz->client->dev.of_node, "kinetic,led-enable-ramp-delay-ms", &val)) {114 if (val == 0)115 ktz8866_write(ktz, BL_DIMMING, 0);116 else {117 unsigned int ramp_off_time = ilog2(val) + 1;118 unsigned int ramp_on_time = ramp_off_time << 4;119 ktz8866_write(ktz, BL_DIMMING, ramp_on_time | ramp_off_time);120 }121 }122 123 if (of_property_read_bool(ktz->client->dev.of_node, "kinetic,enable-lcd-bias"))124 ktz8866_write(ktz, LCD_BIAS_CFG1, LCD_BIAS_EN);125}126 127static int ktz8866_probe(struct i2c_client *client)128{129 struct backlight_device *backlight_dev;130 struct backlight_properties props;131 struct ktz8866 *ktz;132 int ret = 0;133 134 ktz = devm_kzalloc(&client->dev, sizeof(*ktz), GFP_KERNEL);135 if (!ktz)136 return -ENOMEM;137 138 ktz->client = client;139 ktz->regmap = devm_regmap_init_i2c(client, &ktz8866_regmap_config);140 if (IS_ERR(ktz->regmap))141 return dev_err_probe(&client->dev, PTR_ERR(ktz->regmap), "failed to init regmap\n");142 143 ret = devm_regulator_get_enable(&client->dev, "vddpos");144 if (ret)145 return dev_err_probe(&client->dev, ret, "get regulator vddpos failed\n");146 ret = devm_regulator_get_enable(&client->dev, "vddneg");147 if (ret)148 return dev_err_probe(&client->dev, ret, "get regulator vddneg failed\n");149 150 ktz->enable_gpio = devm_gpiod_get_optional(&client->dev, "enable", GPIOD_OUT_HIGH);151 if (IS_ERR(ktz->enable_gpio))152 return PTR_ERR(ktz->enable_gpio);153 154 memset(&props, 0, sizeof(props));155 props.type = BACKLIGHT_RAW;156 props.max_brightness = MAX_BRIGHTNESS;157 props.brightness = DEFAULT_BRIGHTNESS;158 props.scale = BACKLIGHT_SCALE_LINEAR;159 160 backlight_dev = devm_backlight_device_register(&client->dev, "ktz8866-backlight",161 &client->dev, ktz, &ktz8866_backlight_ops, &props);162 if (IS_ERR(backlight_dev))163 return dev_err_probe(&client->dev, PTR_ERR(backlight_dev),164 "failed to register backlight device\n");165 166 ktz8866_init(ktz);167 168 i2c_set_clientdata(client, backlight_dev);169 backlight_update_status(backlight_dev);170 171 return 0;172}173 174static void ktz8866_remove(struct i2c_client *client)175{176 struct backlight_device *backlight_dev = i2c_get_clientdata(client);177 backlight_dev->props.brightness = 0;178 backlight_update_status(backlight_dev);179}180 181static const struct i2c_device_id ktz8866_ids[] = {182 { "ktz8866" },183 {}184};185MODULE_DEVICE_TABLE(i2c, ktz8866_ids);186 187static const struct of_device_id ktz8866_match_table[] = {188 {189 .compatible = "kinetic,ktz8866",190 },191 {},192};193 194static struct i2c_driver ktz8866_driver = {195 .driver = {196 .name = "ktz8866",197 .of_match_table = ktz8866_match_table,198 },199 .probe = ktz8866_probe,200 .remove = ktz8866_remove,201 .id_table = ktz8866_ids,202};203 204module_i2c_driver(ktz8866_driver);205 206MODULE_DESCRIPTION("Kinetic KTZ8866 Backlight Driver");207MODULE_AUTHOR("Jianhua Lu <lujianhua000@gmail.com>");208MODULE_LICENSE("GPL");209