drivers/video/backlight/ktz8866.c

   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" },
 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 MODULE_DEVICE_TABLE(of, ktz8866_match_table);
 194
 195 static struct i2c_driver ktz8866_driver = {
 196         .driver = {
 197                 .name = "ktz8866",
 198                 .of_match_table = ktz8866_match_table,
 199         },
 200         .probe = ktz8866_probe,
 201         .remove = ktz8866_remove,
 202         .id_table = ktz8866_ids,
 203 };
 204
 205 module_i2c_driver(ktz8866_driver);
 206
 207 MODULE_DESCRIPTION("Kinetic KTZ8866 Backlight Driver");
 208 MODULE_AUTHOR("Jianhua Lu <lujianhua000@gmail.com>");
 209 MODULE_LICENSE("GPL");