Eric Lee / smarc-fsl-linux-kernel

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drivers/leds/leds-dac124s085.c 2.55 KB
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81f7e3824   Eric Lee   Initial Release, ... 
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  /*
   * 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;
  
  	for (i = 0; i < ARRAY_SIZE(dac->leds); i++) {
  		led		= dac->leds + i;
  		led->id		= i;
  		led->spi	= spi;
  		snprintf(led->name, sizeof(led->name), "dac124s085-%d", i);
  		mutex_init(&led->mutex);
  		led->ldev.name = led->name;
  		led->ldev.brightness = LED_OFF;
  		led->ldev.max_brightness = 0xfff;
  		led->ldev.brightness_set_blocking = dac124s085_set_brightness;
  		ret = led_classdev_register(&spi->dev, &led->ldev);
  		if (ret < 0)
  			goto eledcr;
  	}
  
  	spi_set_drvdata(spi, dac);
  
  	return 0;
  
  eledcr:
  	while (i--)
  		led_classdev_unregister(&dac->leds[i].ldev);
  
  	return ret;
  }
  
  static int dac124s085_remove(struct spi_device *spi)
  {
  	struct dac124s085	*dac = spi_get_drvdata(spi);
  	int i;
  
  	for (i = 0; i < ARRAY_SIZE(dac->leds); i++)
  		led_classdev_unregister(&dac->leds[i].ldev);
  
  	return 0;
  }
  
  static struct spi_driver dac124s085_driver = {
  	.probe		= dac124s085_probe,
  	.remove		= dac124s085_remove,
  	.driver = {
  		.name	= "dac124s085",
  	},
  };
  
  module_spi_driver(dac124s085_driver);
  
  MODULE_AUTHOR("Guennadi Liakhovetski <lg@denx.de>");
  MODULE_DESCRIPTION("DAC124S085 LED driver");
  MODULE_LICENSE("GPL v2");
  MODULE_ALIAS("spi:dac124s085");