linux-imx

/*

 * Copyright 2008

 * Guennadi Liakhovetski, DENX Software Engineering, <lg@denx.de>

 *

 * This file is subject to the terms and conditions of version 2 of

 * the GNU General Public License.  See the file COPYING in the main

 * directory of this archive for more details.

 *

 * LED driver for the DAC124S085 SPI DAC

 */

​

#include <linux/leds.h>

#include <linux/module.h>

#include <linux/mutex.h>

#include <linux/slab.h>

#include <linux/spi/spi.h>

​

struct dac124s085_led {

    struct led_classdev ldev;

    struct spi_device   *spi;

    int         id;

    char            name[sizeof("dac124s085-3")];

​

    struct mutex        mutex;

};

​

struct dac124s085 {

    struct dac124s085_led leds[4];

};

​

#define REG_WRITE       (0 << 12)

#define REG_WRITE_UPDATE    (1 << 12)

#define ALL_WRITE_UPDATE    (2 << 12)

#define POWER_DOWN_OUTPUT   (3 << 12)

​

static int dac124s085_set_brightness(struct led_classdev *ldev,

                      enum led_brightness brightness)

{

    struct dac124s085_led *led = container_of(ldev, struct dac124s085_led,

                          ldev);

    u16 word;

    int ret;

​

    mutex_lock(&led->mutex);

    word = cpu_to_le16(((led->id) << 14) | REG_WRITE_UPDATE |

               (brightness & 0xfff));

    ret = spi_write(led->spi, (const u8 *)&word, sizeof(word));

    mutex_unlock(&led->mutex);

​

    return ret;

}

​

static int dac124s085_probe(struct spi_device *spi)

{

    struct dac124s085   *dac;

    struct dac124s085_led   *led;

    int i, ret;

​

    dac = devm_kzalloc(&spi->dev, sizeof(*dac), GFP_KERNEL);

    if (!dac)

        return -ENOMEM;

​

    spi->bits_per_word = 16;