drivers/leds/leds-cpcap.c

   1 /*
   2  * Copyright (c) 2017 Sebastian Reichel <sre@kernel.org>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License version 2 or
   6  * later as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  */
  13
  14 #include <linux/leds.h>
  15 #include <linux/mfd/motorola-cpcap.h>
  16 #include <linux/module.h>
  17 #include <linux/mutex.h>
  18 #include <linux/of_device.h>
  19 #include <linux/platform_device.h>
  20 #include <linux/regmap.h>
  21 #include <linux/regulator/consumer.h>
  22
  23 #define CPCAP_LED_NO_CURRENT 0x0001
  24
  25 struct cpcap_led_info {
  26         u16 reg;
  27         u16 mask;
  28         u16 limit;
  29         u16 init_mask;
  30         u16 init_val;
  31 };
  32
  33 static const struct cpcap_led_info cpcap_led_red = {
  34         .reg    = CPCAP_REG_REDC,
  35         .mask   = 0x03FF,
  36         .limit  = 31,
  37 };
  38
  39 static const struct cpcap_led_info cpcap_led_green = {
  40         .reg    = CPCAP_REG_GREENC,
  41         .mask   = 0x03FF,
  42         .limit  = 31,
  43 };
  44
  45 static const struct cpcap_led_info cpcap_led_blue = {
  46         .reg    = CPCAP_REG_BLUEC,
  47         .mask   = 0x03FF,
  48         .limit  = 31,
  49 };
  50
  51 /* aux display light */
  52 static const struct cpcap_led_info cpcap_led_adl = {
  53         .reg            = CPCAP_REG_ADLC,
  54         .mask           = 0x000F,
  55         .limit          = 1,
  56         .init_mask      = 0x7FFF,
  57         .init_val       = 0x5FF0,
  58 };
  59
  60 /* camera privacy led */
  61 static const struct cpcap_led_info cpcap_led_cp = {
  62         .reg            = CPCAP_REG_CLEDC,
  63         .mask           = 0x0007,
  64         .limit          = 1,
  65         .init_mask      = 0x03FF,
  66         .init_val       = 0x0008,
  67 };
  68
  69 struct cpcap_led {
  70         struct led_classdev led;
  71         const struct cpcap_led_info *info;
  72         struct device *dev;
  73         struct regmap *regmap;
  74         struct mutex update_lock;
  75         struct regulator *vdd;
  76         bool powered;
  77
  78         u32 current_limit;
  79 };
  80
  81 static u16 cpcap_led_val(u8 current_limit, u8 duty_cycle)
  82 {
  83         current_limit &= 0x1f; /* 5 bit */
  84         duty_cycle &= 0x0f; /* 4 bit */
  85
  86         return current_limit << 4 | duty_cycle;
  87 }
  88
  89 static int cpcap_led_set_power(struct cpcap_led *led, bool status)
  90 {
  91         int err;
  92
  93         if (status == led->powered)
  94                 return 0;
  95
  96         if (status)
  97                 err = regulator_enable(led->vdd);
  98         else
  99                 err = regulator_disable(led->vdd);
 100
 101         if (err) {
 102                 dev_err(led->dev, "regulator failure: %d", err);
 103                 return err;
 104         }
 105
 106         led->powered = status;
 107
 108         return 0;
 109 }
 110
 111 static int cpcap_led_set(struct led_classdev *ledc, enum led_brightness value)
 112 {
 113         struct cpcap_led *led = container_of(ledc, struct cpcap_led, led);
 114         int brightness;
 115         int err;
 116
 117         mutex_lock(&led->update_lock);
 118
 119         if (value > LED_OFF) {
 120                 err = cpcap_led_set_power(led, true);
 121                 if (err)
 122                         goto exit;
 123         }
 124
 125         if (value == LED_OFF) {
 126                 /* Avoid HW issue by turning off current before duty cycle */
 127                 err = regmap_update_bits(led->regmap,
 128                         led->info->reg, led->info->mask, CPCAP_LED_NO_CURRENT);
 129                 if (err) {
 130                         dev_err(led->dev, "regmap failed: %d", err);
 131                         goto exit;
 132                 }
 133
 134                 brightness = cpcap_led_val(value, LED_OFF);
 135         } else {
 136                 brightness = cpcap_led_val(value, LED_ON);
 137         }
 138
 139         err = regmap_update_bits(led->regmap, led->info->reg, led->info->mask,
 140                 brightness);
 141         if (err) {
 142                 dev_err(led->dev, "regmap failed: %d", err);
 143                 goto exit;
 144         }
 145
 146         if (value == LED_OFF) {
 147                 err = cpcap_led_set_power(led, false);
 148                 if (err)
 149                         goto exit;
 150         }
 151
 152 exit:
 153         mutex_unlock(&led->update_lock);
 154         return err;
 155 }
 156
 157 static const struct of_device_id cpcap_led_of_match[] = {
 158         { .compatible = "motorola,cpcap-led-red", .data = &cpcap_led_red },
 159         { .compatible = "motorola,cpcap-led-green", .data = &cpcap_led_green },
 160         { .compatible = "motorola,cpcap-led-blue",  .data = &cpcap_led_blue },
 161         { .compatible = "motorola,cpcap-led-adl", .data = &cpcap_led_adl },
 162         { .compatible = "motorola,cpcap-led-cp", .data = &cpcap_led_cp },
 163         {},
 164 };
 165 MODULE_DEVICE_TABLE(of, cpcap_led_of_match);
 166
 167 static int cpcap_led_probe(struct platform_device *pdev)
 168 {
 169         const struct of_device_id *match;
 170         struct cpcap_led *led;
 171         int err;
 172
 173         match = of_match_device(of_match_ptr(cpcap_led_of_match), &pdev->dev);
 174         if (!match || !match->data)
 175                 return -EINVAL;
 176
 177         led = devm_kzalloc(&pdev->dev, sizeof(*led), GFP_KERNEL);
 178         if (!led)
 179                 return -ENOMEM;
 180         platform_set_drvdata(pdev, led);
 181         led->info = match->data;
 182         led->dev = &pdev->dev;
 183
 184         if (led->info->reg == 0x0000) {
 185                 dev_err(led->dev, "Unsupported LED");
 186                 return -ENODEV;
 187         }
 188
 189         led->regmap = dev_get_regmap(pdev->dev.parent, NULL);
 190         if (!led->regmap)
 191                 return -ENODEV;
 192
 193         led->vdd = devm_regulator_get(&pdev->dev, "vdd");
 194         if (IS_ERR(led->vdd)) {
 195                 err = PTR_ERR(led->vdd);
 196                 dev_err(led->dev, "Couldn't get regulator: %d", err);
 197                 return err;
 198         }
 199
 200         err = device_property_read_string(&pdev->dev, "label", &led->led.name);
 201         if (err) {
 202                 dev_err(led->dev, "Couldn't read LED label: %d", err);
 203                 return err;
 204         }
 205
 206         if (led->info->init_mask) {
 207                 err = regmap_update_bits(led->regmap, led->info->reg,
 208                         led->info->init_mask, led->info->init_val);
 209                 if (err) {
 210                         dev_err(led->dev, "regmap failed: %d", err);
 211                         return err;
 212                 }
 213         }
 214
 215         mutex_init(&led->update_lock);
 216
 217         led->led.max_brightness = led->info->limit;
 218         led->led.brightness_set_blocking = cpcap_led_set;
 219         err = devm_led_classdev_register(&pdev->dev, &led->led);
 220         if (err) {
 221                 dev_err(led->dev, "Couldn't register LED: %d", err);
 222                 return err;
 223         }
 224
 225         return 0;
 226 }
 227
 228 static struct platform_driver cpcap_led_driver = {
 229         .probe = cpcap_led_probe,
 230         .driver = {
 231                 .name = "cpcap-led",
 232                 .of_match_table = cpcap_led_of_match,
 233         },
 234 };
 235 module_platform_driver(cpcap_led_driver);
 236
 237 MODULE_DESCRIPTION("CPCAP LED driver");
 238 MODULE_AUTHOR("Sebastian Reichel <sre@kernel.org>");
 239 MODULE_LICENSE("GPL");