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_SPI */
  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 ad714x_chip *chip,
  34                            unsigned short reg, unsigned short *data)
  35 {
  36         struct spi_device *spi = to_spi_device(chip->dev);
  37         struct spi_message message;
  38         struct spi_transfer xfer[2];
  39         int error;
  40
  41         spi_message_init(&message);
  42         memset(xfer, 0, sizeof(xfer));
  43
  44         chip->xfer_buf[0] = cpu_to_be16(AD714x_SPI_CMD_PREFIX |
  45                                         AD714x_SPI_READ | reg);
  46         xfer[0].tx_buf = &chip->xfer_buf[0];
  47         xfer[0].len = sizeof(chip->xfer_buf[0]);
  48         spi_message_add_tail(&xfer[0], &message);
  49
  50         xfer[1].rx_buf = &chip->xfer_buf[1];
  51         xfer[1].len = sizeof(chip->xfer_buf[1]);
  52         spi_message_add_tail(&xfer[1], &message);
  53
  54         error = spi_sync(spi, &message);
  55         if (unlikely(error)) {
  56                 dev_err(chip->dev, "SPI read error: %d\n", error);
  57                 return error;
  58         }
  59
  60         *data = be16_to_cpu(chip->xfer_buf[1]);
  61         return 0;
  62 }
  63
  64 static int ad714x_spi_write(struct ad714x_chip *chip,
  65                             unsigned short reg, unsigned short data)
  66 {
  67         struct spi_device *spi = to_spi_device(chip->dev);
  68         int error;
  69
  70         chip->xfer_buf[0] = cpu_to_be16(AD714x_SPI_CMD_PREFIX | reg);
  71         chip->xfer_buf[1] = cpu_to_be16(data);
  72
  73         error = spi_write(spi, (u8 *)chip->xfer_buf,
  74                           2 * sizeof(*chip->xfer_buf));
  75         if (unlikely(error)) {
  76                 dev_err(chip->dev, "SPI write error: %d\n", error);
  77                 return error;
  78         }
  79
  80         return 0;
  81 }
  82
  83 static int __devinit ad714x_spi_probe(struct spi_device *spi)
  84 {
  85         struct ad714x_chip *chip;
  86         int err;
  87
  88         spi->bits_per_word = 8;
  89         err = spi_setup(spi);
  90         if (err < 0)
  91                 return err;
  92
  93         chip = ad714x_probe(&spi->dev, BUS_SPI, spi->irq,
  94                             ad714x_spi_read, ad714x_spi_write);
  95         if (IS_ERR(chip))
  96                 return PTR_ERR(chip);
  97
  98         spi_set_drvdata(spi, chip);
  99
 100         return 0;
 101 }
 102
 103 static int __devexit ad714x_spi_remove(struct spi_device *spi)
 104 {
 105         struct ad714x_chip *chip = spi_get_drvdata(spi);
 106
 107         ad714x_remove(chip);
 108         spi_set_drvdata(spi, NULL);
 109
 110         return 0;
 111 }
 112
 113 static struct spi_driver ad714x_spi_driver = {
 114         .driver = {
 115                 .name   = "ad714x_captouch",
 116                 .owner  = THIS_MODULE,
 117                 .pm     = &ad714x_spi_pm,
 118         },
 119         .probe          = ad714x_spi_probe,
 120         .remove         = __devexit_p(ad714x_spi_remove),
 121 };
 122
 123 static __init int ad714x_spi_init(void)
 124 {
 125         return spi_register_driver(&ad714x_spi_driver);
 126 }
 127 module_init(ad714x_spi_init);
 128
 129 static __exit void ad714x_spi_exit(void)
 130 {
 131         spi_unregister_driver(&ad714x_spi_driver);
 132 }
 133 module_exit(ad714x_spi_exit);
 134
 135 MODULE_DESCRIPTION("Analog Devices AD714X Capacitance Touch Sensor SPI Bus Driver");
 136 MODULE_AUTHOR("Barry Song <21cnbao@gmail.com>");
 137 MODULE_LICENSE("GPL");