drivers/input/misc/ad714x-spi.c

   1 /*
   2  * AD714X CapTouch Programmable Controller driver (SPI bus)
   3  *
   4  * Copyright 2009-2011 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, size_t len)
  35 {
  36         struct spi_device *spi = to_spi_device(chip->dev);
  37         struct spi_message message;
  38         struct spi_transfer xfer[2];
  39         int i;
  40         int error;
  41
  42         spi_message_init(&message);
  43         memset(xfer, 0, sizeof(xfer));
  44
  45         chip->xfer_buf[0] = cpu_to_be16(AD714x_SPI_CMD_PREFIX |
  46                                         AD714x_SPI_READ | reg);
  47         xfer[0].tx_buf = &chip->xfer_buf[0];
  48         xfer[0].len = sizeof(chip->xfer_buf[0]);
  49         spi_message_add_tail(&xfer[0], &message);
  50
  51         xfer[1].rx_buf = &chip->xfer_buf[1];
  52         xfer[1].len = sizeof(chip->xfer_buf[1]) * len;
  53         spi_message_add_tail(&xfer[1], &message);
  54
  55         error = spi_sync(spi, &message);
  56         if (unlikely(error)) {
  57                 dev_err(chip->dev, "SPI read error: %d\n", error);
  58                 return error;
  59         }
  60
  61         for (i = 0; i < len; i++)
  62                 data[i] = be16_to_cpu(chip->xfer_buf[i + 1]);
  63
  64         return 0;
  65 }
  66
  67 static int ad714x_spi_write(struct ad714x_chip *chip,
  68                             unsigned short reg, unsigned short data)
  69 {
  70         struct spi_device *spi = to_spi_device(chip->dev);
  71         int error;
  72
  73         chip->xfer_buf[0] = cpu_to_be16(AD714x_SPI_CMD_PREFIX | reg);
  74         chip->xfer_buf[1] = cpu_to_be16(data);
  75
  76         error = spi_write(spi, (u8 *)chip->xfer_buf,
  77                           2 * sizeof(*chip->xfer_buf));
  78         if (unlikely(error)) {
  79                 dev_err(chip->dev, "SPI write error: %d\n", error);
  80                 return error;
  81         }
  82
  83         return 0;
  84 }
  85
  86 static int __devinit ad714x_spi_probe(struct spi_device *spi)
  87 {
  88         struct ad714x_chip *chip;
  89         int err;
  90
  91         spi->bits_per_word = 8;
  92         err = spi_setup(spi);
  93         if (err < 0)
  94                 return err;
  95
  96         chip = ad714x_probe(&spi->dev, BUS_SPI, spi->irq,
  97                             ad714x_spi_read, ad714x_spi_write);
  98         if (IS_ERR(chip))
  99                 return PTR_ERR(chip);
 100
 101         spi_set_drvdata(spi, chip);
 102
 103         return 0;
 104 }
 105
 106 static int __devexit ad714x_spi_remove(struct spi_device *spi)
 107 {
 108         struct ad714x_chip *chip = spi_get_drvdata(spi);
 109
 110         ad714x_remove(chip);
 111         spi_set_drvdata(spi, NULL);
 112
 113         return 0;
 114 }
 115
 116 static struct spi_driver ad714x_spi_driver = {
 117         .driver = {
 118                 .name   = "ad714x_captouch",
 119                 .owner  = THIS_MODULE,
 120                 .pm     = &ad714x_spi_pm,
 121         },
 122         .probe          = ad714x_spi_probe,
 123         .remove         = __devexit_p(ad714x_spi_remove),
 124 };
 125
 126 static __init int ad714x_spi_init(void)
 127 {
 128         return spi_register_driver(&ad714x_spi_driver);
 129 }
 130 module_init(ad714x_spi_init);
 131
 132 static __exit void ad714x_spi_exit(void)
 133 {
 134         spi_unregister_driver(&ad714x_spi_driver);
 135 }
 136 module_exit(ad714x_spi_exit);
 137
 138 MODULE_DESCRIPTION("Analog Devices AD714X Capacitance Touch Sensor SPI Bus Driver");
 139 MODULE_AUTHOR("Barry Song <21cnbao@gmail.com>");
 140 MODULE_LICENSE("GPL");