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/types.h>
  13 #include "ad714x.h"
  14
  15 #define AD714x_SPI_CMD_PREFIX      0xE000   /* bits 15:11 */
  16 #define AD714x_SPI_READ            BIT(10)
  17
  18 #ifdef CONFIG_PM
  19 static int ad714x_spi_suspend(struct spi_device *spi, pm_message_t message)
  20 {
  21         return ad714x_disable(spi_get_drvdata(spi));
  22 }
  23
  24 static int ad714x_spi_resume(struct spi_device *spi)
  25 {
  26         return ad714x_enable(spi_get_drvdata(spi));
  27 }
  28 #else
  29 # define ad714x_spi_suspend NULL
  30 # define ad714x_spi_resume  NULL
  31 #endif
  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
  58         chip = ad714x_probe(&spi->dev, BUS_SPI, spi->irq,
  59                             ad714x_spi_read, ad714x_spi_write);
  60         if (IS_ERR(chip))
  61                 return PTR_ERR(chip);
  62
  63         spi_set_drvdata(spi, chip);
  64
  65         return 0;
  66 }
  67
  68 static int __devexit ad714x_spi_remove(struct spi_device *spi)
  69 {
  70         struct ad714x_chip *chip = spi_get_drvdata(spi);
  71
  72         ad714x_remove(chip);
  73         spi_set_drvdata(spi, NULL);
  74
  75         return 0;
  76 }
  77
  78 static struct spi_driver ad714x_spi_driver = {
  79         .driver = {
  80                 .name   = "ad714x_captouch",
  81                 .owner  = THIS_MODULE,
  82         },
  83         .probe          = ad714x_spi_probe,
  84         .remove         = __devexit_p(ad714x_spi_remove),
  85         .suspend        = ad714x_spi_suspend,
  86         .resume         = ad714x_spi_resume,
  87 };
  88
  89 static __init int ad714x_spi_init(void)
  90 {
  91         return spi_register_driver(&ad714x_spi_driver);
  92 }
  93 module_init(ad714x_spi_init);
  94
  95 static __exit void ad714x_spi_exit(void)
  96 {
  97         spi_unregister_driver(&ad714x_spi_driver);
  98 }
  99 module_exit(ad714x_spi_exit);
 100
 101 MODULE_DESCRIPTION("Analog Devices AD714X Capacitance Touch Sensor SPI Bus Driver");
 102 MODULE_AUTHOR("Barry Song <21cnbao@gmail.com>");
 103 MODULE_LICENSE("GPL");