drivers/leds/leds-ariel.c

   1 // SPDX-License-Identifier: BSD-2-Clause OR GPL-2.0-or-later
   2 /*
   3  * Dell Wyse 3020 a.k.a. "Ariel" Embedded Controller LED Driver
   4  *
   5  * Copyright (C) 2020 Lubomir Rintel
   6  */
   7
   8 #include <linux/module.h>
   9 #include <linux/leds.h>
  10 #include <linux/regmap.h>
  11 #include <linux/of_platform.h>
  12
  13 enum ec_index {
  14         EC_BLUE_LED     = 0x01,
  15         EC_AMBER_LED    = 0x02,
  16         EC_GREEN_LED    = 0x03,
  17 };
  18
  19 enum {
  20         EC_LED_OFF      = 0x00,
  21         EC_LED_STILL    = 0x01,
  22         EC_LED_FADE     = 0x02,
  23         EC_LED_BLINK    = 0x03,
  24 };
  25
  26 struct ariel_led {
  27         struct regmap *ec_ram;
  28         enum ec_index ec_index;
  29         struct led_classdev led_cdev;
  30 };
  31
  32 #define led_cdev_to_ariel_led(c) container_of(c, struct ariel_led, led_cdev)
  33
  34 static enum led_brightness ariel_led_get(struct led_classdev *led_cdev)
  35 {
  36         struct ariel_led *led = led_cdev_to_ariel_led(led_cdev);
  37         unsigned int led_status = 0;
  38
  39         if (regmap_read(led->ec_ram, led->ec_index, &led_status))
  40                 return LED_OFF;
  41
  42         if (led_status == EC_LED_STILL)
  43                 return LED_FULL;
  44         else
  45                 return LED_OFF;
  46 }
  47
  48 static void ariel_led_set(struct led_classdev *led_cdev,
  49                           enum led_brightness brightness)
  50 {
  51         struct ariel_led *led = led_cdev_to_ariel_led(led_cdev);
  52
  53         if (brightness == LED_OFF)
  54                 regmap_write(led->ec_ram, led->ec_index, EC_LED_OFF);
  55         else
  56                 regmap_write(led->ec_ram, led->ec_index, EC_LED_STILL);
  57 }
  58
  59 static int ariel_blink_set(struct led_classdev *led_cdev,
  60                            unsigned long *delay_on, unsigned long *delay_off)
  61 {
  62         struct ariel_led *led = led_cdev_to_ariel_led(led_cdev);
  63
  64         if (*delay_on == 0 && *delay_off == 0)
  65                 return -EINVAL;
  66
  67         if (*delay_on == 0) {
  68                 regmap_write(led->ec_ram, led->ec_index, EC_LED_OFF);
  69         } else if (*delay_off == 0) {
  70                 regmap_write(led->ec_ram, led->ec_index, EC_LED_STILL);
  71         } else {
  72                 *delay_on = 500;
  73                 *delay_off = 500;
  74                 regmap_write(led->ec_ram, led->ec_index, EC_LED_BLINK);
  75         }
  76
  77         return 0;
  78 }
  79
  80 #define NLEDS 3
  81
  82 static int ariel_led_probe(struct platform_device *pdev)
  83 {
  84         struct device *dev = &pdev->dev;
  85         struct ariel_led *leds;
  86         struct regmap *ec_ram;
  87         int ret;
  88         int i;
  89
  90         ec_ram = dev_get_regmap(dev->parent, "ec_ram");
  91         if (!ec_ram)
  92                 return -ENODEV;
  93
  94         leds = devm_kcalloc(dev, NLEDS, sizeof(*leds), GFP_KERNEL);
  95         if (!leds)
  96                 return -ENOMEM;
  97
  98         leds[0].ec_index = EC_BLUE_LED;
  99         leds[0].led_cdev.name = "blue:power";
 100         leds[0].led_cdev.default_trigger = "default-on";
 101
 102         leds[1].ec_index = EC_AMBER_LED;
 103         leds[1].led_cdev.name = "amber:status";
 104
 105         leds[2].ec_index = EC_GREEN_LED;
 106         leds[2].led_cdev.name = "green:status";
 107         leds[2].led_cdev.default_trigger = "default-on";
 108
 109         for (i = 0; i < NLEDS; i++) {
 110                 leds[i].ec_ram = ec_ram;
 111                 leds[i].led_cdev.brightness_get = ariel_led_get;
 112                 leds[i].led_cdev.brightness_set = ariel_led_set;
 113                 leds[i].led_cdev.blink_set = ariel_blink_set;
 114
 115                 ret = devm_led_classdev_register(dev, &leds[i].led_cdev);
 116                 if (ret)
 117                         return ret;
 118         }
 119
 120         return 0;
 121 }
 122
 123 static struct platform_driver ariel_led_driver = {
 124         .probe = ariel_led_probe,
 125         .driver = {
 126                 .name = "dell-wyse-ariel-led",
 127         },
 128 };
 129 module_platform_driver(ariel_led_driver);
 130
 131 MODULE_AUTHOR("Lubomir Rintel <lkundrak@v3.sk>");
 132 MODULE_DESCRIPTION("Dell Wyse 3020 Status LEDs Driver");
 133 MODULE_LICENSE("Dual BSD/GPL");