LXR linux/drivers/leds/leds-dac124s085.c

   1/*
   2 * Copyright 2008
   3 * Guennadi Liakhovetski, DENX Software Engineering, <lg@denx.de>
   4 *
   5 * This file is subject to the terms and conditions of version 2 of
   6 * the GNU General Public License.  See the file COPYING in the main
   7 * directory of this archive for more details.
   8 *
   9 * LED driver for the DAC124S085 SPI DAC
  10 */
  11
  12#include <linux/leds.h>
  13#include <linux/module.h>
  14#include <linux/mutex.h>
  15#include <linux/slab.h>
  16#include <linux/spi/spi.h>
  17
  18struct dac124s085_led {
  19        struct led_classdev     ldev;
  20        struct spi_device       *spi;
  21        int                     id;
  22        char                    name[sizeof("dac124s085-3")];
  23
  24        struct mutex            mutex;
  25};
  26
  27struct dac124s085 {
  28        struct dac124s085_led leds[4];
  29};
  30
  31#define REG_WRITE               (0 << 12)
  32#define REG_WRITE_UPDATE        (1 << 12)
  33#define ALL_WRITE_UPDATE        (2 << 12)
  34#define POWER_DOWN_OUTPUT       (3 << 12)
  35
  36static int dac124s085_set_brightness(struct led_classdev *ldev,
  37                                      enum led_brightness brightness)
  38{
  39        struct dac124s085_led *led = container_of(ldev, struct dac124s085_led,
  40                                                  ldev);
  41        u16 word;
  42        int ret;
  43
  44        mutex_lock(&led->mutex);
  45        word = cpu_to_le16(((led->id) << 14) | REG_WRITE_UPDATE |
  46                           (brightness & 0xfff));
  47        ret = spi_write(led->spi, (const u8 *)&word, sizeof(word));
  48        mutex_unlock(&led->mutex);
  49
  50        return ret;
  51}
  52
  53static int dac124s085_probe(struct spi_device *spi)
  54{
  55        struct dac124s085       *dac;
  56        struct dac124s085_led   *led;
  57        int i, ret;
  58
  59        dac = devm_kzalloc(&spi->dev, sizeof(*dac), GFP_KERNEL);
  60        if (!dac)
  61                return -ENOMEM;
  62
  63        spi->bits_per_word = 16;
  64
  65        for (i = 0; i < ARRAY_SIZE(dac->leds); i++) {
  66                led             = dac->leds + i;
  67                led->id         = i;
  68                led->spi        = spi;
  69                snprintf(led->name, sizeof(led->name), "dac124s085-%d", i);
  70                mutex_init(&led->mutex);
  71                led->ldev.name = led->name;
  72                led->ldev.brightness = LED_OFF;
  73                led->ldev.max_brightness = 0xfff;
  74                led->ldev.brightness_set_blocking = dac124s085_set_brightness;
  75                ret = led_classdev_register(&spi->dev, &led->ldev);
  76                if (ret < 0)
  77                        goto eledcr;
  78        }
  79
  80        spi_set_drvdata(spi, dac);
  81
  82        return 0;
  83
  84eledcr:
  85        while (i--)
  86                led_classdev_unregister(&dac->leds[i].ldev);
  87
  88        return ret;
  89}
  90
  91static int dac124s085_remove(struct spi_device *spi)
  92{
  93        struct dac124s085       *dac = spi_get_drvdata(spi);
  94        int i;
  95
  96        for (i = 0; i < ARRAY_SIZE(dac->leds); i++)
  97                led_classdev_unregister(&dac->leds[i].ldev);
  98
  99        return 0;
 100}
 101
 102static struct spi_driver dac124s085_driver = {
 103        .probe          = dac124s085_probe,
 104        .remove         = dac124s085_remove,
 105        .driver = {
 106                .name   = "dac124s085",
 107        },
 108};
 109
 110module_spi_driver(dac124s085_driver);
 111
 112MODULE_AUTHOR("Guennadi Liakhovetski <lg@denx.de>");
 113MODULE_DESCRIPTION("DAC124S085 LED driver");
 114MODULE_LICENSE("GPL v2");
 115MODULE_ALIAS("spi:dac124s085");
 116