drivers/leds/leds-dac124s085.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright 2008
   4  * Guennadi Liakhovetski, DENX Software Engineering, <lg@denx.de>
   5  *
   6  * LED driver for the DAC124S085 SPI DAC
   7  */
   8
   9 #include <linux/leds.h>
  10 #include <linux/module.h>
  11 #include <linux/mutex.h>
  12 #include <linux/slab.h>
  13 #include <linux/spi/spi.h>
  14
  15 struct dac124s085_led {
  16         struct led_classdev     ldev;
  17         struct spi_device       *spi;
  18         int                     id;
  19         char                    name[sizeof("dac124s085-3")];
  20
  21         struct mutex            mutex;
  22 };
  23
  24 struct dac124s085 {
  25         struct dac124s085_led leds[4];
  26 };
  27
  28 #define REG_WRITE               (0 << 12)
  29 #define REG_WRITE_UPDATE        (1 << 12)
  30 #define ALL_WRITE_UPDATE        (2 << 12)
  31 #define POWER_DOWN_OUTPUT       (3 << 12)
  32
  33 static int dac124s085_set_brightness(struct led_classdev *ldev,
  34                                       enum led_brightness brightness)
  35 {
  36         struct dac124s085_led *led = container_of(ldev, struct dac124s085_led,
  37                                                   ldev);
  38         u16 word;
  39         int ret;
  40
  41         mutex_lock(&led->mutex);
  42         word = cpu_to_le16(((led->id) << 14) | REG_WRITE_UPDATE |
  43                            (brightness & 0xfff));
  44         ret = spi_write(led->spi, (const u8 *)&word, sizeof(word));
  45         mutex_unlock(&led->mutex);
  46
  47         return ret;
  48 }
  49
  50 static int dac124s085_probe(struct spi_device *spi)
  51 {
  52         struct dac124s085       *dac;
  53         struct dac124s085_led   *led;
  54         int i, ret;
  55
  56         dac = devm_kzalloc(&spi->dev, sizeof(*dac), GFP_KERNEL);
  57         if (!dac)
  58                 return -ENOMEM;
  59
  60         spi->bits_per_word = 16;
  61
  62         for (i = 0; i < ARRAY_SIZE(dac->leds); i++) {
  63                 led             = dac->leds + i;
  64                 led->id         = i;
  65                 led->spi        = spi;
  66                 snprintf(led->name, sizeof(led->name), "dac124s085-%d", i);
  67                 mutex_init(&led->mutex);
  68                 led->ldev.name = led->name;
  69                 led->ldev.brightness = LED_OFF;
  70                 led->ldev.max_brightness = 0xfff;
  71                 led->ldev.brightness_set_blocking = dac124s085_set_brightness;
  72                 ret = led_classdev_register(&spi->dev, &led->ldev);
  73                 if (ret < 0)
  74                         goto eledcr;
  75         }
  76
  77         spi_set_drvdata(spi, dac);
  78
  79         return 0;
  80
  81 eledcr:
  82         while (i--)
  83                 led_classdev_unregister(&dac->leds[i].ldev);
  84
  85         return ret;
  86 }
  87
  88 static int dac124s085_remove(struct spi_device *spi)
  89 {
  90         struct dac124s085       *dac = spi_get_drvdata(spi);
  91         int i;
  92
  93         for (i = 0; i < ARRAY_SIZE(dac->leds); i++)
  94                 led_classdev_unregister(&dac->leds[i].ldev);
  95
  96         return 0;
  97 }
  98
  99 static struct spi_driver dac124s085_driver = {
 100         .probe          = dac124s085_probe,
 101         .remove         = dac124s085_remove,
 102         .driver = {
 103                 .name   = "dac124s085",
 104         },
 105 };
 106
 107 module_spi_driver(dac124s085_driver);
 108
 109 MODULE_AUTHOR("Guennadi Liakhovetski <lg@denx.de>");
 110 MODULE_DESCRIPTION("DAC124S085 LED driver");
 111 MODULE_LICENSE("GPL v2");
 112 MODULE_ALIAS("spi:dac124s085");