drivers/input/misc/adxl34x-spi.c

   1 /*
   2  * ADLX345/346 Three-Axis Digital Accelerometers (SPI Interface)
   3  *
   4  * Enter bugs at http://blackfin.uclinux.org/
   5  *
   6  * Copyright (C) 2009 Michael Hennerich, Analog Devices Inc.
   7  * Licensed under the GPL-2 or later.
   8  */
   9
  10 #include <linux/input.h>        /* BUS_SPI */
  11 #include <linux/module.h>
  12 #include <linux/spi/spi.h>
  13 #include <linux/types.h>
  14 #include "adxl34x.h"
  15
  16 #define MAX_SPI_FREQ_HZ         5000000
  17 #define MAX_FREQ_NO_FIFODELAY   1500000
  18 #define ADXL34X_CMD_MULTB       (1 << 6)
  19 #define ADXL34X_CMD_READ        (1 << 7)
  20 #define ADXL34X_WRITECMD(reg)   (reg & 0x3F)
  21 #define ADXL34X_READCMD(reg)    (ADXL34X_CMD_READ | (reg & 0x3F))
  22 #define ADXL34X_READMB_CMD(reg) (ADXL34X_CMD_READ | ADXL34X_CMD_MULTB \
  23                                         | (reg & 0x3F))
  24
  25 static int adxl34x_spi_read(struct device *dev, unsigned char reg)
  26 {
  27         struct spi_device *spi = to_spi_device(dev);
  28         unsigned char cmd;
  29
  30         cmd = ADXL34X_READCMD(reg);
  31
  32         return spi_w8r8(spi, cmd);
  33 }
  34
  35 static int adxl34x_spi_write(struct device *dev,
  36                              unsigned char reg, unsigned char val)
  37 {
  38         struct spi_device *spi = to_spi_device(dev);
  39         unsigned char buf[2];
  40
  41         buf[0] = ADXL34X_WRITECMD(reg);
  42         buf[1] = val;
  43
  44         return spi_write(spi, buf, sizeof(buf));
  45 }
  46
  47 static int adxl34x_spi_read_block(struct device *dev,
  48                                   unsigned char reg, int count,
  49                                   void *buf)
  50 {
  51         struct spi_device *spi = to_spi_device(dev);
  52         ssize_t status;
  53
  54         reg = ADXL34X_READMB_CMD(reg);
  55         status = spi_write_then_read(spi, &reg, 1, buf, count);
  56
  57         return (status < 0) ? status : 0;
  58 }
  59
  60 static const struct adxl34x_bus_ops adx134x_spi_bops = {
  61         .bustype        = BUS_SPI,
  62         .write          = adxl34x_spi_write,
  63         .read           = adxl34x_spi_read,
  64         .read_block     = adxl34x_spi_read_block,
  65 };
  66
  67 static int __devinit adxl34x_spi_probe(struct spi_device *spi)
  68 {
  69         struct adxl34x *ac;
  70
  71         /* don't exceed max specified SPI CLK frequency */
  72         if (spi->max_speed_hz > MAX_SPI_FREQ_HZ) {
  73                 dev_err(&spi->dev, "SPI CLK %d Hz too fast\n", spi->max_speed_hz);
  74                 return -EINVAL;
  75         }
  76
  77         ac = adxl34x_probe(&spi->dev, spi->irq,
  78                            spi->max_speed_hz > MAX_FREQ_NO_FIFODELAY,
  79                            &adx134x_spi_bops);
  80
  81         if (IS_ERR(ac))
  82                 return PTR_ERR(ac);
  83
  84         spi_set_drvdata(spi, ac);
  85
  86         return 0;
  87 }
  88
  89 static int __devexit adxl34x_spi_remove(struct spi_device *spi)
  90 {
  91         struct adxl34x *ac = dev_get_drvdata(&spi->dev);
  92
  93         return adxl34x_remove(ac);
  94 }
  95
  96 #ifdef CONFIG_PM
  97 static int adxl34x_spi_suspend(struct spi_device *spi, pm_message_t message)
  98 {
  99         struct adxl34x *ac = dev_get_drvdata(&spi->dev);
 100
 101         adxl34x_suspend(ac);
 102
 103         return 0;
 104 }
 105
 106 static int adxl34x_spi_resume(struct spi_device *spi)
 107 {
 108         struct adxl34x *ac = dev_get_drvdata(&spi->dev);
 109
 110         adxl34x_resume(ac);
 111
 112         return 0;
 113 }
 114 #else
 115 # define adxl34x_spi_suspend NULL
 116 # define adxl34x_spi_resume  NULL
 117 #endif
 118
 119 static struct spi_driver adxl34x_driver = {
 120         .driver = {
 121                 .name = "adxl34x",
 122                 .bus = &spi_bus_type,
 123                 .owner = THIS_MODULE,
 124         },
 125         .probe   = adxl34x_spi_probe,
 126         .remove  = __devexit_p(adxl34x_spi_remove),
 127         .suspend = adxl34x_spi_suspend,
 128         .resume  = adxl34x_spi_resume,
 129 };
 130
 131 static int __init adxl34x_spi_init(void)
 132 {
 133         return spi_register_driver(&adxl34x_driver);
 134 }
 135 module_init(adxl34x_spi_init);
 136
 137 static void __exit adxl34x_spi_exit(void)
 138 {
 139         spi_unregister_driver(&adxl34x_driver);
 140 }
 141 module_exit(adxl34x_spi_exit);
 142
 143 MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
 144 MODULE_DESCRIPTION("ADXL345/346 Three-Axis Digital Accelerometer SPI Bus Driver");
 145 MODULE_LICENSE("GPL");