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         {.name = "ad5270", .devid = AD5270_ID},
  42         {.name = "ad5271", .devid = AD5271_ID},
  43         {}
  44 };
  45
  46 /* ------------------------------------------------------------------------- */
  47
  48 /* SPI bus functions */
  49 static int write8(void *client, u8 val)
  50 {
  51         u8 data = val;
  52         return spi_write(client, &data, 1);
  53 }
  54
  55 static int write16(void *client, u8 reg, u8 val)
  56 {
  57         u8 data[2] = {reg, val};
  58         return spi_write(client, data, 2);
  59 }
  60
  61 static int write24(void *client, u8 reg, u16 val)
  62 {
  63         u8 data[3] = {reg, val >> 8, val};
  64         return spi_write(client, data, 3);
  65 }
  66
  67 static int read8(void *client)
  68 {
  69         int ret;
  70         u8 data;
  71         ret = spi_read(client, &data, 1);
  72         if (ret < 0)
  73                 return ret;
  74
  75         return data;
  76 }
  77
  78 static int read16(void *client, u8 reg)
  79 {
  80         int ret;
  81         u8 buf_rx[2];
  82
  83         write16(client, reg, 0);
  84         ret = spi_read(client, buf_rx, 2);
  85         if (ret < 0)
  86                 return ret;
  87
  88         return (buf_rx[0] << 8) |  buf_rx[1];
  89 }
  90
  91 static int read24(void *client, u8 reg)
  92 {
  93         int ret;
  94         u8 buf_rx[3];
  95
  96         write24(client, reg, 0);
  97         ret = spi_read(client, buf_rx, 3);
  98         if (ret < 0)
  99                 return ret;
 100
 101         return (buf_rx[1] << 8) |  buf_rx[2];
 102 }
 103
 104 static const struct ad_dpot_bus_ops bops = {
 105         .read_d8        = read8,
 106         .read_r8d8      = read16,
 107         .read_r8d16     = read24,
 108         .write_d8       = write8,
 109         .write_r8d8     = write16,
 110         .write_r8d16    = write24,
 111 };
 112
 113 static const struct ad_dpot_id *dpot_match_id(const struct ad_dpot_id *id,
 114                                                 char *name)
 115 {
 116         while (id->name && id->name[0]) {
 117                 if (strcmp(name, id->name) == 0)
 118                         return id;
 119                 id++;
 120         }
 121         return NULL;
 122 }
 123
 124 static int __devinit ad_dpot_spi_probe(struct spi_device *spi)
 125 {
 126         char *name = spi->dev.platform_data;
 127         const struct ad_dpot_id *dpot_id;
 128
 129         struct ad_dpot_bus_data bdata = {
 130                 .client = spi,
 131                 .bops = &bops,
 132         };
 133
 134         dpot_id = dpot_match_id(ad_dpot_spi_devlist, name);
 135
 136         if (dpot_id == NULL) {
 137                 dev_err(&spi->dev, "%s not in supported device list", name);
 138                 return -ENODEV;
 139         }
 140
 141         return ad_dpot_probe(&spi->dev, &bdata, dpot_id);
 142 }
 143
 144 static int __devexit ad_dpot_spi_remove(struct spi_device *spi)
 145 {
 146         return ad_dpot_remove(&spi->dev);
 147 }
 148
 149 static struct spi_driver ad_dpot_spi_driver = {
 150         .driver = {
 151                 .name   = "ad_dpot",
 152                 .bus    = &spi_bus_type,
 153                 .owner  = THIS_MODULE,
 154         },
 155         .probe          = ad_dpot_spi_probe,
 156         .remove         = __devexit_p(ad_dpot_spi_remove),
 157 };
 158
 159 static int __init ad_dpot_spi_init(void)
 160 {
 161         return spi_register_driver(&ad_dpot_spi_driver);
 162 }
 163 module_init(ad_dpot_spi_init);
 164
 165 static void __exit ad_dpot_spi_exit(void)
 166 {
 167         spi_unregister_driver(&ad_dpot_spi_driver);
 168 }
 169 module_exit(ad_dpot_spi_exit);
 170
 171 MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
 172 MODULE_DESCRIPTION("digital potentiometer SPI bus driver");
 173 MODULE_LICENSE("GPL");
 174 MODULE_ALIAS("spi:ad_dpot");