drivers/misc/ad525x_dpot-spi.c

   1 /*
   2  * Driver for the Analog Devices digital potentiometers (SPI bus)
   3  *
   4  * Copyright (C) 2010-2011 Michael Hennerich, Analog Devices Inc.
   5  *
   6  * Licensed under the GPL-2 or later.
   7  */
   8
   9 #include <linux/spi/spi.h>
  10 #include <linux/module.h>
  11
  12 #include "ad525x_dpot.h"
  13
  14 /* SPI bus functions */
  15 static int write8(void *client, u8 val)
  16 {
  17         u8 data = val;
  18         return spi_write(client, &data, 1);
  19 }
  20
  21 static int write16(void *client, u8 reg, u8 val)
  22 {
  23         u8 data[2] = {reg, val};
  24         return spi_write(client, data, 2);
  25 }
  26
  27 static int write24(void *client, u8 reg, u16 val)
  28 {
  29         u8 data[3] = {reg, val >> 8, val};
  30         return spi_write(client, data, 3);
  31 }
  32
  33 static int read8(void *client)
  34 {
  35         int ret;
  36         u8 data;
  37         ret = spi_read(client, &data, 1);
  38         if (ret < 0)
  39                 return ret;
  40
  41         return data;
  42 }
  43
  44 static int read16(void *client, u8 reg)
  45 {
  46         int ret;
  47         u8 buf_rx[2];
  48
  49         write16(client, reg, 0);
  50         ret = spi_read(client, buf_rx, 2);
  51         if (ret < 0)
  52                 return ret;
  53
  54         return (buf_rx[0] << 8) |  buf_rx[1];
  55 }
  56
  57 static int read24(void *client, u8 reg)
  58 {
  59         int ret;
  60         u8 buf_rx[3];
  61
  62         write24(client, reg, 0);
  63         ret = spi_read(client, buf_rx, 3);
  64         if (ret < 0)
  65                 return ret;
  66
  67         return (buf_rx[1] << 8) |  buf_rx[2];
  68 }
  69
  70 static const struct ad_dpot_bus_ops bops = {
  71         .read_d8        = read8,
  72         .read_r8d8      = read16,
  73         .read_r8d16     = read24,
  74         .write_d8       = write8,
  75         .write_r8d8     = write16,
  76         .write_r8d16    = write24,
  77 };
  78 static int __devinit ad_dpot_spi_probe(struct spi_device *spi)
  79 {
  80         struct ad_dpot_bus_data bdata = {
  81                 .client = spi,
  82                 .bops = &bops,
  83         };
  84
  85         return ad_dpot_probe(&spi->dev, &bdata,
  86                              spi_get_device_id(spi)->driver_data,
  87                              spi_get_device_id(spi)->name);
  88 }
  89
  90 static int __devexit ad_dpot_spi_remove(struct spi_device *spi)
  91 {
  92         return ad_dpot_remove(&spi->dev);
  93 }
  94
  95 static const struct spi_device_id ad_dpot_spi_id[] = {
  96         {"ad5160", AD5160_ID},
  97         {"ad5161", AD5161_ID},
  98         {"ad5162", AD5162_ID},
  99         {"ad5165", AD5165_ID},
 100         {"ad5200", AD5200_ID},
 101         {"ad5201", AD5201_ID},
 102         {"ad5203", AD5203_ID},
 103         {"ad5204", AD5204_ID},
 104         {"ad5206", AD5206_ID},
 105         {"ad5207", AD5207_ID},
 106         {"ad5231", AD5231_ID},
 107         {"ad5232", AD5232_ID},
 108         {"ad5233", AD5233_ID},
 109         {"ad5235", AD5235_ID},
 110         {"ad5260", AD5260_ID},
 111         {"ad5262", AD5262_ID},
 112         {"ad5263", AD5263_ID},
 113         {"ad5290", AD5290_ID},
 114         {"ad5291", AD5291_ID},
 115         {"ad5292", AD5292_ID},
 116         {"ad5293", AD5293_ID},
 117         {"ad7376", AD7376_ID},
 118         {"ad8400", AD8400_ID},
 119         {"ad8402", AD8402_ID},
 120         {"ad8403", AD8403_ID},
 121         {"adn2850", ADN2850_ID},
 122         {"ad5270", AD5270_ID},
 123         {"ad5271", AD5271_ID},
 124         {}
 125 };
 126 MODULE_DEVICE_TABLE(spi, ad_dpot_spi_id);
 127
 128 static struct spi_driver ad_dpot_spi_driver = {
 129         .driver = {
 130                 .name   = "ad_dpot",
 131                 .owner  = THIS_MODULE,
 132         },
 133         .probe          = ad_dpot_spi_probe,
 134         .remove         = __devexit_p(ad_dpot_spi_remove),
 135         .id_table       = ad_dpot_spi_id,
 136 };
 137
 138 static int __init ad_dpot_spi_init(void)
 139 {
 140         return spi_register_driver(&ad_dpot_spi_driver);
 141 }
 142 module_init(ad_dpot_spi_init);
 143
 144 static void __exit ad_dpot_spi_exit(void)
 145 {
 146         spi_unregister_driver(&ad_dpot_spi_driver);
 147 }
 148 module_exit(ad_dpot_spi_exit);
 149
 150 MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
 151 MODULE_DESCRIPTION("digital potentiometer SPI bus driver");
 152 MODULE_LICENSE("GPL");
 153 MODULE_ALIAS("spi:ad_dpot");