drivers/input/misc/ad714x-spi.c

   1 /*
   2  * AD714X CapTouch Programmable Controller driver (SPI bus)
   3  *
   4  * Copyright 2009 Analog Devices Inc.
   5  *
   6  * Licensed under the GPL-2 or later.
   7  */
   8
   9 #include <linux/input.h>        /* BUS_I2C */
  10 #include <linux/module.h>
  11 #include <linux/spi/spi.h>
  12 #include <linux/pm.h>
  13 #include <linux/types.h>
  14 #include "ad714x.h"
  15
  16 #define AD714x_SPI_CMD_PREFIX      0xE000   /* bits 15:11 */
  17 #define AD714x_SPI_READ            BIT(10)
  18
  19 #ifdef CONFIG_PM
  20 static int ad714x_spi_suspend(struct device *dev)
  21 {
  22         return ad714x_disable(spi_get_drvdata(to_spi_device(dev)));
  23 }
  24
  25 static int ad714x_spi_resume(struct device *dev)
  26 {
  27         return ad714x_enable(spi_get_drvdata(to_spi_device(dev)));
  28 }
  29 #endif
  30
  31 static SIMPLE_DEV_PM_OPS(ad714x_spi_pm, ad714x_spi_suspend, ad714x_spi_resume);
  32
  33 static int ad714x_spi_read(struct device *dev, unsigned short reg,
  34                 unsigned short *data)
  35 {
  36         struct spi_device *spi = to_spi_device(dev);
  37         unsigned short tx = AD714x_SPI_CMD_PREFIX | AD714x_SPI_READ | reg;
  38
  39         return spi_write_then_read(spi, (u8 *)&tx, 2, (u8 *)data, 2);
  40 }
  41
  42 static int ad714x_spi_write(struct device *dev, unsigned short reg,
  43                 unsigned short data)
  44 {
  45         struct spi_device *spi = to_spi_device(dev);
  46         unsigned short tx[2] = {
  47                 AD714x_SPI_CMD_PREFIX | reg,
  48                 data
  49         };
  50
  51         return spi_write(spi, (u8 *)tx, 4);
  52 }
  53
  54 static int __devinit ad714x_spi_probe(struct spi_device *spi)
  55 {
  56         struct ad714x_chip *chip;
  57         int err;
  58
  59         spi->bits_per_word = 8;
  60         err = spi_setup(spi);
  61         if (err < 0)
  62                 return err;
  63
  64         chip = ad714x_probe(&spi->dev, BUS_SPI, spi->irq,
  65                             ad714x_spi_read, ad714x_spi_write);
  66         if (IS_ERR(chip))
  67                 return PTR_ERR(chip);
  68
  69         spi_set_drvdata(spi, chip);
  70
  71         return 0;
  72 }
  73
  74 static int __devexit ad714x_spi_remove(struct spi_device *spi)
  75 {
  76         struct ad714x_chip *chip = spi_get_drvdata(spi);
  77
  78         ad714x_remove(chip);
  79         spi_set_drvdata(spi, NULL);
  80
  81         return 0;
  82 }
  83
  84 static struct spi_driver ad714x_spi_driver = {
  85         .driver = {
  86                 .name   = "ad714x_captouch",
  87                 .owner  = THIS_MODULE,
  88                 .pm     = &ad714x_spi_pm,
  89         },
  90         .probe          = ad714x_spi_probe,
  91         .remove         = __devexit_p(ad714x_spi_remove),
  92 };
  93
  94 static __init int ad714x_spi_init(void)
  95 {
  96         return spi_register_driver(&ad714x_spi_driver);
  97 }
  98 module_init(ad714x_spi_init);
  99
 100 static __exit void ad714x_spi_exit(void)
 101 {
 102         spi_unregister_driver(&ad714x_spi_driver);
 103 }
 104 module_exit(ad714x_spi_exit);
 105
 106 MODULE_DESCRIPTION("Analog Devices AD714X Capacitance Touch Sensor SPI Bus Driver");
 107 MODULE_AUTHOR("Barry Song <21cnbao@gmail.com>");
 108 MODULE_LICENSE("GPL");