drivers/misc/ad525x_dpot-spi.c

   1 /*
   2  * Driver for the Analog Devices digital potentiometers (SPI bus)
   3  *
   4  * Copyright (C) 2010 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 static const struct ad_dpot_id ad_dpot_spi_devlist[] = {
  15         {.name = "ad5160", .devid = AD5160_ID},
  16         {.name = "ad5161", .devid = AD5161_ID},
  17         {.name = "ad5162", .devid = AD5162_ID},
  18         {.name = "ad5165", .devid = AD5165_ID},
  19         {.name = "ad5200", .devid = AD5200_ID},
  20         {.name = "ad5201", .devid = AD5201_ID},
  21         {.name = "ad5203", .devid = AD5203_ID},
  22         {.name = "ad5204", .devid = AD5204_ID},
  23         {.name = "ad5206", .devid = AD5206_ID},
  24         {.name = "ad5207", .devid = AD5207_ID},
  25         {.name = "ad5231", .devid = AD5231_ID},
  26         {.name = "ad5232", .devid = AD5232_ID},
  27         {.name = "ad5233", .devid = AD5233_ID},
  28         {.name = "ad5235", .devid = AD5235_ID},
  29         {.name = "ad5260", .devid = AD5260_ID},
  30         {.name = "ad5262", .devid = AD5262_ID},
  31         {.name = "ad5263", .devid = AD5263_ID},
  32         {.name = "ad5290", .devid = AD5290_ID},
  33         {.name = "ad5291", .devid = AD5291_ID},
  34         {.name = "ad5292", .devid = AD5292_ID},
  35         {.name = "ad5293", .devid = AD5293_ID},
  36         {.name = "ad7376", .devid = AD7376_ID},
  37         {.name = "ad8400", .devid = AD8400_ID},
  38         {.name = "ad8402", .devid = AD8402_ID},
  39         {.name = "ad8403", .devid = AD8403_ID},
  40         {.name = "adn2850", .devid = ADN2850_ID},
  41         {}
  42 };
  43
  44 /* ------------------------------------------------------------------------- */
  45
  46 /* SPI bus functions */
  47 static int write8(void *client, u8 val)
  48 {
  49         u8 data = val;
  50         return spi_write(client, &data, 1);
  51 }
  52
  53 static int write16(void *client, u8 reg, u8 val)
  54 {
  55         u8 data[2] = {reg, val};
  56         return spi_write(client, data, 1);
  57 }
  58
  59 static int write24(void *client, u8 reg, u16 val)
  60 {
  61         u8 data[3] = {reg, val >> 8, val};
  62         return spi_write(client, data, 1);
  63 }
  64
  65 static int read8(void *client)
  66 {
  67         int ret;
  68         u8 data;
  69         ret = spi_read(client, &data, 1);
  70         if (ret < 0)
  71                 return ret;
  72
  73         return data;
  74 }
  75
  76 static int read16(void *client, u8 reg)
  77 {
  78         int ret;
  79         u8 buf_rx[2];
  80
  81         write16(client, reg, 0);
  82         ret = spi_read(client, buf_rx, 2);
  83         if (ret < 0)
  84                 return ret;
  85
  86         return (buf_rx[0] << 8) |  buf_rx[1];
  87 }
  88
  89 static int read24(void *client, u8 reg)
  90 {
  91         int ret;
  92         u8 buf_rx[3];
  93
  94         write24(client, reg, 0);
  95         ret = spi_read(client, buf_rx, 3);
  96         if (ret < 0)
  97                 return ret;
  98
  99         return (buf_rx[1] << 8) |  buf_rx[2];
 100 }
 101
 102 static const struct ad_dpot_bus_ops bops = {
 103         .read_d8        = read8,
 104         .read_r8d8      = read16,
 105         .read_r8d16     = read24,
 106         .write_d8       = write8,
 107         .write_r8d8     = write16,
 108         .write_r8d16    = write24,
 109 };
 110
 111 static const struct ad_dpot_id *dpot_match_id(const struct ad_dpot_id *id,
 112                                                 char *name)
 113 {
 114         while (id->name && id->name[0]) {
 115                 if (strcmp(name, id->name) == 0)
 116                         return id;
 117                 id++;
 118         }
 119         return NULL;
 120 }
 121
 122 static int __devinit ad_dpot_spi_probe(struct spi_device *spi)
 123 {
 124         char *name = spi->dev.platform_data;
 125         const struct ad_dpot_id *dpot_id;
 126
 127         struct ad_dpot_bus_data bdata = {
 128                 .client = spi,
 129                 .bops = &bops,
 130         };
 131
 132         dpot_id = dpot_match_id(ad_dpot_spi_devlist, name);
 133
 134         if (dpot_id == NULL) {
 135                 dev_err(&spi->dev, "%s not in supported device list", name);
 136                 return -ENODEV;
 137         }
 138
 139         return ad_dpot_probe(&spi->dev, &bdata, dpot_id);
 140 }
 141
 142 static int __devexit ad_dpot_spi_remove(struct spi_device *spi)
 143 {
 144         return ad_dpot_remove(&spi->dev);
 145 }
 146
 147 static struct spi_driver ad_dpot_spi_driver = {
 148         .driver = {
 149                 .name   = "ad_dpot",
 150                 .bus    = &spi_bus_type,
 151                 .owner  = THIS_MODULE,
 152         },
 153         .probe          = ad_dpot_spi_probe,
 154         .remove         = __devexit_p(ad_dpot_spi_remove),
 155 };
 156
 157 static int __init ad_dpot_spi_init(void)
 158 {
 159         return spi_register_driver(&ad_dpot_spi_driver);
 160 }
 161 module_init(ad_dpot_spi_init);
 162
 163 static void __exit ad_dpot_spi_exit(void)
 164 {
 165         spi_unregister_driver(&ad_dpot_spi_driver);
 166 }
 167 module_exit(ad_dpot_spi_exit);
 168
 169 MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
 170 MODULE_DESCRIPTION("digital potentiometer SPI bus driver");
 171 MODULE_LICENSE("GPL");
 172 MODULE_ALIAS("spi:ad_dpot");