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kernel/linux-imx6_3.14.28/drivers/input/misc/adxl34x-spi.c 3.07 KB
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  /*
   * ADLX345/346 Three-Axis Digital Accelerometers (SPI Interface)
   *
   * Enter bugs at http://blackfin.uclinux.org/
   *
   * Copyright (C) 2009 Michael Hennerich, Analog Devices Inc.
   * Licensed under the GPL-2 or later.
   */
  
  #include <linux/input.h>	/* BUS_SPI */
  #include <linux/module.h>
  #include <linux/spi/spi.h>
  #include <linux/pm.h>
  #include <linux/types.h>
  #include "adxl34x.h"
  
  #define MAX_SPI_FREQ_HZ		5000000
  #define MAX_FREQ_NO_FIFODELAY	1500000
  #define ADXL34X_CMD_MULTB	(1 << 6)
  #define ADXL34X_CMD_READ	(1 << 7)
  #define ADXL34X_WRITECMD(reg)	(reg & 0x3F)
  #define ADXL34X_READCMD(reg)	(ADXL34X_CMD_READ | (reg & 0x3F))
  #define ADXL34X_READMB_CMD(reg) (ADXL34X_CMD_READ | ADXL34X_CMD_MULTB \
  					| (reg & 0x3F))
  
  static int adxl34x_spi_read(struct device *dev, unsigned char reg)
  {
  	struct spi_device *spi = to_spi_device(dev);
  	unsigned char cmd;
  
  	cmd = ADXL34X_READCMD(reg);
  
  	return spi_w8r8(spi, cmd);
  }
  
  static int adxl34x_spi_write(struct device *dev,
  			     unsigned char reg, unsigned char val)
  {
  	struct spi_device *spi = to_spi_device(dev);
  	unsigned char buf[2];
  
  	buf[0] = ADXL34X_WRITECMD(reg);
  	buf[1] = val;
  
  	return spi_write(spi, buf, sizeof(buf));
  }
  
  static int adxl34x_spi_read_block(struct device *dev,
  				  unsigned char reg, int count,
  				  void *buf)
  {
  	struct spi_device *spi = to_spi_device(dev);
  	ssize_t status;
  
  	reg = ADXL34X_READMB_CMD(reg);
  	status = spi_write_then_read(spi, &reg, 1, buf, count);
  
  	return (status < 0) ? status : 0;
  }
  
  static const struct adxl34x_bus_ops adxl34x_spi_bops = {
  	.bustype	= BUS_SPI,
  	.write		= adxl34x_spi_write,
  	.read		= adxl34x_spi_read,
  	.read_block	= adxl34x_spi_read_block,
  };
  
  static int adxl34x_spi_probe(struct spi_device *spi)
  {
  	struct adxl34x *ac;
  
  	/* don't exceed max specified SPI CLK frequency */
  	if (spi->max_speed_hz > MAX_SPI_FREQ_HZ) {
  		dev_err(&spi->dev, "SPI CLK %d Hz too fast
  ", spi->max_speed_hz);
  		return -EINVAL;
  	}
  
  	ac = adxl34x_probe(&spi->dev, spi->irq,
  			   spi->max_speed_hz > MAX_FREQ_NO_FIFODELAY,
  			   &adxl34x_spi_bops);
  
  	if (IS_ERR(ac))
  		return PTR_ERR(ac);
  
  	spi_set_drvdata(spi, ac);
  
  	return 0;
  }
  
  static int adxl34x_spi_remove(struct spi_device *spi)
  {
  	struct adxl34x *ac = spi_get_drvdata(spi);
  
  	return adxl34x_remove(ac);
  }
  
  #ifdef CONFIG_PM_SLEEP
  static int adxl34x_spi_suspend(struct device *dev)
  {
  	struct spi_device *spi = to_spi_device(dev);
  	struct adxl34x *ac = spi_get_drvdata(spi);
  
  	adxl34x_suspend(ac);
  
  	return 0;
  }
  
  static int adxl34x_spi_resume(struct device *dev)
  {
  	struct spi_device *spi = to_spi_device(dev);
  	struct adxl34x *ac = spi_get_drvdata(spi);
  
  	adxl34x_resume(ac);
  
  	return 0;
  }
  #endif
  
  static SIMPLE_DEV_PM_OPS(adxl34x_spi_pm, adxl34x_spi_suspend,
  			 adxl34x_spi_resume);
  
  static struct spi_driver adxl34x_driver = {
  	.driver = {
  		.name = "adxl34x",
  		.owner = THIS_MODULE,
  		.pm = &adxl34x_spi_pm,
  	},
  	.probe   = adxl34x_spi_probe,
  	.remove  = adxl34x_spi_remove,
  };
  
  module_spi_driver(adxl34x_driver);
  
  MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
  MODULE_DESCRIPTION("ADXL345/346 Three-Axis Digital Accelerometer SPI Bus Driver");
  MODULE_LICENSE("GPL");