1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Backlight driver for the Kinetic KTZ8866 4 * 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 1500 17 #define MAX_BRIGHTNESS 2047 18 #define REG_MAX 0x15 19 20 /* reg */ 21 #define DEVICE_ID 0x01 22 #define BL_CFG1 0x02 23 #define BL_CFG2 0x03 24 #define BL_BRT_LSB 0x04 25 #define BL_BRT_MSB 0x05 26 #define BL_EN 0x08 27 #define LCD_BIAS_CFG1 0x09 28 #define LCD_BIAS_CFG2 0x0A 29 #define LCD_BIAS_CFG3 0x0B 30 #define LCD_BOOST_CFG 0x0C 31 #define OUTP_CFG 0x0D 32 #define OUTN_CFG 0x0E 33 #define FLAG 0x0F 34 #define BL_OPTION1 0x10 35 #define BL_OPTION2 0x11 36 #define PWM2DIG_LSBs 0x12 37 #define PWM2DIG_MSBs 0x13 38 #define BL_DIMMING 0x14 39 #define PWM_RAMP_TIME 0x15 40 41 /* definition */ 42 #define BL_EN_BIT BIT(6) 43 #define LCD_BIAS_EN 0x9F 44 #define PWM_HYST 0x5 45 46 struct ktz8866 { 47 struct i2c_client *client; 48 struct regmap *regmap; 49 bool led_on; 50 struct gpio_desc *enable_gpio; 51 }; 52 53 static const struct regmap_config ktz8866_regmap_config = { 54 .reg_bits = 8, 55 .val_bits = 8, 56 .max_register = REG_MAX, 57 }; 58 59 static int ktz8866_write(struct ktz8866 *ktz, unsigned int reg, 60 unsigned int val) 61 { 62 return regmap_write(ktz->regmap, reg, val); 63 } 64 65 static 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 71 static 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 91 static const struct backlight_ops ktz8866_backlight_ops = { 92 .options = BL_CORE_SUSPENDRESUME, 93 .update_status = ktz8866_backlight_update_status, 94 }; 95 96 static 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 else 103 /* 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 else 110 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 } 126 127 static 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 } 173 174 static 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 } 180 181 static const struct i2c_device_id ktz8866_ids[] = { 182 { "ktz8866", 0 }, 183 {}, 184 }; 185 MODULE_DEVICE_TABLE(i2c, ktz8866_ids); 186 187 static const struct of_device_id ktz8866_match_table[] = { 188 { 189 .compatible = "kinetic,ktz8866", 190 }, 191 {}, 192 }; 193 194 static 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 }; 203 204 module_i2c_driver(ktz8866_driver); 205 206 MODULE_DESCRIPTION("Kinetic KTZ8866 Backlight Driver"); 207 MODULE_AUTHOR("Jianhua Lu <lujianhua000@gmail.com>"); 208 MODULE_LICENSE("GPL"); 209