drivers/iio/dac/max517.c

   1 /*
   2  *  max517.c - Support for Maxim MAX517, MAX518 and MAX519
   3  *
   4  *  Copyright (C) 2010, 2011 Roland Stigge <stigge@antcom.de>
   5  *
   6  *  This program is free software; you can redistribute it and/or modify
   7  *  it under the terms of the GNU General Public License as published by
   8  *  the Free Software Foundation; either version 2 of the License, or
   9  *  (at your option) any later version.
  10  *
  11  *  This program is distributed in the hope that it will be useful,
  12  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  *  GNU General Public License for more details.
  15  *
  16  *  You should have received a copy of the GNU General Public License
  17  *  along with this program; if not, write to the Free Software
  18  *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  19  */
  20
  21 #include <linux/module.h>
  22 #include <linux/slab.h>
  23 #include <linux/jiffies.h>
  24 #include <linux/i2c.h>
  25 #include <linux/err.h>
  26
  27 #include <linux/iio/iio.h>
  28 #include <linux/iio/sysfs.h>
  29 #include <linux/iio/dac/max517.h>
  30
  31 #define MAX517_DRV_NAME "max517"
  32
  33 /* Commands */
  34 #define COMMAND_CHANNEL0        0x00
  35 #define COMMAND_CHANNEL1        0x01 /* for MAX518 and MAX519 */
  36 #define COMMAND_PD              0x08 /* Power Down */
  37
  38 enum max517_device_ids {
  39         ID_MAX517,
  40         ID_MAX518,
  41         ID_MAX519,
  42         ID_MAX520,
  43         ID_MAX521,
  44 };
  45
  46 struct max517_data {
  47         struct i2c_client       *client;
  48         unsigned short          vref_mv[8];
  49 };
  50
  51 /*
  52  * channel: bit 0: channel 1
  53  *          bit 1: channel 2
  54  * (this way, it's possible to set both channels at once)
  55  */
  56 static int max517_set_value(struct iio_dev *indio_dev,
  57         long val, int channel)
  58 {
  59         struct max517_data *data = iio_priv(indio_dev);
  60         struct i2c_client *client = data->client;
  61         u8 outbuf[2];
  62         int res;
  63
  64         if (val < 0 || val > 255)
  65                 return -EINVAL;
  66
  67         outbuf[0] = channel;
  68         outbuf[1] = val;
  69
  70         res = i2c_master_send(client, outbuf, 2);
  71         if (res < 0)
  72                 return res;
  73         else if (res != 2)
  74                 return -EIO;
  75         else
  76                 return 0;
  77 }
  78
  79 static int max517_read_raw(struct iio_dev *indio_dev,
  80                            struct iio_chan_spec const *chan,
  81                            int *val,
  82                            int *val2,
  83                            long m)
  84 {
  85         struct max517_data *data = iio_priv(indio_dev);
  86
  87         switch (m) {
  88         case IIO_CHAN_INFO_SCALE:
  89                 /* Corresponds to Vref / 2^(bits) */
  90                 *val = data->vref_mv[chan->channel];
  91                 *val2 = 8;
  92                 return IIO_VAL_FRACTIONAL_LOG2;
  93         default:
  94                 break;
  95         }
  96         return -EINVAL;
  97 }
  98
  99 static int max517_write_raw(struct iio_dev *indio_dev,
 100         struct iio_chan_spec const *chan, int val, int val2, long mask)
 101 {
 102         int ret;
 103
 104         switch (mask) {
 105         case IIO_CHAN_INFO_RAW:
 106                 ret = max517_set_value(indio_dev, val, chan->channel);
 107                 break;
 108         default:
 109                 ret = -EINVAL;
 110                 break;
 111         }
 112
 113         return ret;
 114 }
 115
 116 #ifdef CONFIG_PM_SLEEP
 117 static int max517_suspend(struct device *dev)
 118 {
 119         u8 outbuf = COMMAND_PD;
 120
 121         return i2c_master_send(to_i2c_client(dev), &outbuf, 1);
 122 }
 123
 124 static int max517_resume(struct device *dev)
 125 {
 126         u8 outbuf = 0;
 127
 128         return i2c_master_send(to_i2c_client(dev), &outbuf, 1);
 129 }
 130
 131 static SIMPLE_DEV_PM_OPS(max517_pm_ops, max517_suspend, max517_resume);
 132 #define MAX517_PM_OPS (&max517_pm_ops)
 133 #else
 134 #define MAX517_PM_OPS NULL
 135 #endif
 136
 137 static const struct iio_info max517_info = {
 138         .read_raw = max517_read_raw,
 139         .write_raw = max517_write_raw,
 140 };
 141
 142 #define MAX517_CHANNEL(chan) {                          \
 143         .type = IIO_VOLTAGE,                            \
 144         .indexed = 1,                                   \
 145         .output = 1,                                    \
 146         .channel = (chan),                              \
 147         .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |  \
 148         BIT(IIO_CHAN_INFO_SCALE),                       \
 149 }
 150
 151 static const struct iio_chan_spec max517_channels[] = {
 152         MAX517_CHANNEL(0),
 153         MAX517_CHANNEL(1),
 154         MAX517_CHANNEL(2),
 155         MAX517_CHANNEL(3),
 156         MAX517_CHANNEL(4),
 157         MAX517_CHANNEL(5),
 158         MAX517_CHANNEL(6),
 159         MAX517_CHANNEL(7),
 160 };
 161
 162 static int max517_probe(struct i2c_client *client,
 163                         const struct i2c_device_id *id)
 164 {
 165         struct max517_data *data;
 166         struct iio_dev *indio_dev;
 167         struct max517_platform_data *platform_data = client->dev.platform_data;
 168         int chan;
 169
 170         indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
 171         if (!indio_dev)
 172                 return -ENOMEM;
 173         data = iio_priv(indio_dev);
 174         i2c_set_clientdata(client, indio_dev);
 175         data->client = client;
 176
 177         /* establish that the iio_dev is a child of the i2c device */
 178         indio_dev->dev.parent = &client->dev;
 179
 180         switch (id->driver_data) {
 181         case ID_MAX521:
 182                 indio_dev->num_channels = 8;
 183                 break;
 184         case ID_MAX520:
 185                 indio_dev->num_channels = 4;
 186                 break;
 187         case ID_MAX519:
 188         case ID_MAX518:
 189                 indio_dev->num_channels = 2;
 190                 break;
 191         default:  /* single channel for MAX517 */
 192                 indio_dev->num_channels = 1;
 193                 break;
 194         }
 195         indio_dev->channels = max517_channels;
 196         indio_dev->modes = INDIO_DIRECT_MODE;
 197         indio_dev->info = &max517_info;
 198
 199         /*
 200          * Reference voltage on MAX518 and default is 5V, else take vref_mv
 201          * from platform_data
 202          */
 203         for (chan = 0; chan < indio_dev->num_channels; chan++) {
 204                 if (id->driver_data == ID_MAX518 || !platform_data)
 205                         data->vref_mv[chan] = 5000; /* mV */
 206                 else
 207                         data->vref_mv[chan] = platform_data->vref_mv[chan];
 208         }
 209
 210         return iio_device_register(indio_dev);
 211 }
 212
 213 static int max517_remove(struct i2c_client *client)
 214 {
 215         iio_device_unregister(i2c_get_clientdata(client));
 216         return 0;
 217 }
 218
 219 static const struct i2c_device_id max517_id[] = {
 220         { "max517", ID_MAX517 },
 221         { "max518", ID_MAX518 },
 222         { "max519", ID_MAX519 },
 223         { "max520", ID_MAX520 },
 224         { "max521", ID_MAX521 },
 225         { }
 226 };
 227 MODULE_DEVICE_TABLE(i2c, max517_id);
 228
 229 static struct i2c_driver max517_driver = {
 230         .driver = {
 231                 .name   = MAX517_DRV_NAME,
 232                 .pm             = MAX517_PM_OPS,
 233         },
 234         .probe          = max517_probe,
 235         .remove         = max517_remove,
 236         .id_table       = max517_id,
 237 };
 238 module_i2c_driver(max517_driver);
 239
 240 MODULE_AUTHOR("Roland Stigge <stigge@antcom.de>");
 241 MODULE_DESCRIPTION("MAX517/518/519/520/521 8-bit DAC");
 242 MODULE_LICENSE("GPL");