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/init.h>
  23 #include <linux/slab.h>
  24 #include <linux/jiffies.h>
  25 #include <linux/i2c.h>
  26 #include <linux/err.h>
  27
  28 #include <linux/iio/iio.h>
  29 #include <linux/iio/sysfs.h>
  30 #include <linux/iio/dac/max517.h>
  31
  32 #define MAX517_DRV_NAME "max517"
  33
  34 /* Commands */
  35 #define COMMAND_CHANNEL0        0x00
  36 #define COMMAND_CHANNEL1        0x01 /* for MAX518 and MAX519 */
  37 #define COMMAND_PD              0x08 /* Power Down */
  38
  39 enum max517_device_ids {
  40         ID_MAX517,
  41         ID_MAX518,
  42         ID_MAX519,
  43 };
  44
  45 struct max517_data {
  46         struct i2c_client       *client;
  47         unsigned short          vref_mv[2];
  48 };
  49
  50 /*
  51  * channel: bit 0: channel 1
  52  *          bit 1: channel 2
  53  * (this way, it's possible to set both channels at once)
  54  */
  55 static int max517_set_value(struct iio_dev *indio_dev,
  56         long val, int channel)
  57 {
  58         struct max517_data *data = iio_priv(indio_dev);
  59         struct i2c_client *client = data->client;
  60         u8 outbuf[2];
  61         int res;
  62
  63         if (val < 0 || val > 255)
  64                 return -EINVAL;
  65
  66         outbuf[0] = channel;
  67         outbuf[1] = val;
  68
  69         res = i2c_master_send(client, outbuf, 2);
  70         if (res < 0)
  71                 return res;
  72         else if (res != 2)
  73                 return -EIO;
  74         else
  75                 return 0;
  76 }
  77
  78 static int max517_read_raw(struct iio_dev *indio_dev,
  79                            struct iio_chan_spec const *chan,
  80                            int *val,
  81                            int *val2,
  82                            long m)
  83 {
  84         struct max517_data *data = iio_priv(indio_dev);
  85
  86         switch (m) {
  87         case IIO_CHAN_INFO_SCALE:
  88                 /* Corresponds to Vref / 2^(bits) */
  89                 *val = data->vref_mv[chan->channel];
  90                 *val2 = 8;
  91                 return IIO_VAL_FRACTIONAL_LOG2;
  92         default:
  93                 break;
  94         }
  95         return -EINVAL;
  96 }
  97
  98 static int max517_write_raw(struct iio_dev *indio_dev,
  99         struct iio_chan_spec const *chan, int val, int val2, long mask)
 100 {
 101         int ret;
 102
 103         switch (mask) {
 104         case IIO_CHAN_INFO_RAW:
 105                 ret = max517_set_value(indio_dev, val, chan->channel);
 106                 break;
 107         default:
 108                 ret = -EINVAL;
 109                 break;
 110         }
 111
 112         return ret;
 113 }
 114
 115 #ifdef CONFIG_PM_SLEEP
 116 static int max517_suspend(struct device *dev)
 117 {
 118         u8 outbuf = COMMAND_PD;
 119
 120         return i2c_master_send(to_i2c_client(dev), &outbuf, 1);
 121 }
 122
 123 static int max517_resume(struct device *dev)
 124 {
 125         u8 outbuf = 0;
 126
 127         return i2c_master_send(to_i2c_client(dev), &outbuf, 1);
 128 }
 129
 130 static SIMPLE_DEV_PM_OPS(max517_pm_ops, max517_suspend, max517_resume);
 131 #define MAX517_PM_OPS (&max517_pm_ops)
 132 #else
 133 #define MAX517_PM_OPS NULL
 134 #endif
 135
 136 static const struct iio_info max517_info = {
 137         .read_raw = max517_read_raw,
 138         .write_raw = max517_write_raw,
 139         .driver_module = THIS_MODULE,
 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 };
 155
 156 static int max517_probe(struct i2c_client *client,
 157                         const struct i2c_device_id *id)
 158 {
 159         struct max517_data *data;
 160         struct iio_dev *indio_dev;
 161         struct max517_platform_data *platform_data = client->dev.platform_data;
 162
 163         indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
 164         if (!indio_dev)
 165                 return -ENOMEM;
 166         data = iio_priv(indio_dev);
 167         i2c_set_clientdata(client, indio_dev);
 168         data->client = client;
 169
 170         /* establish that the iio_dev is a child of the i2c device */
 171         indio_dev->dev.parent = &client->dev;
 172
 173         /* reduced channel set for MAX517 */
 174         if (id->driver_data == ID_MAX517)
 175                 indio_dev->num_channels = 1;
 176         else
 177                 indio_dev->num_channels = 2;
 178         indio_dev->channels = max517_channels;
 179         indio_dev->modes = INDIO_DIRECT_MODE;
 180         indio_dev->info = &max517_info;
 181
 182         /*
 183          * Reference voltage on MAX518 and default is 5V, else take vref_mv
 184          * from platform_data
 185          */
 186         if (id->driver_data == ID_MAX518 || !platform_data) {
 187                 data->vref_mv[0] = data->vref_mv[1] = 5000; /* mV */
 188         } else {
 189                 data->vref_mv[0] = platform_data->vref_mv[0];
 190                 data->vref_mv[1] = platform_data->vref_mv[1];
 191         }
 192
 193         return iio_device_register(indio_dev);
 194 }
 195
 196 static int max517_remove(struct i2c_client *client)
 197 {
 198         iio_device_unregister(i2c_get_clientdata(client));
 199         return 0;
 200 }
 201
 202 static const struct i2c_device_id max517_id[] = {
 203         { "max517", ID_MAX517 },
 204         { "max518", ID_MAX518 },
 205         { "max519", ID_MAX519 },
 206         { }
 207 };
 208 MODULE_DEVICE_TABLE(i2c, max517_id);
 209
 210 static struct i2c_driver max517_driver = {
 211         .driver = {
 212                 .name   = MAX517_DRV_NAME,
 213                 .pm             = MAX517_PM_OPS,
 214         },
 215         .probe          = max517_probe,
 216         .remove         = max517_remove,
 217         .id_table       = max517_id,
 218 };
 219 module_i2c_driver(max517_driver);
 220
 221 MODULE_AUTHOR("Roland Stigge <stigge@antcom.de>");
 222 MODULE_DESCRIPTION("MAX517/MAX518/MAX519 8-bit DAC");
 223 MODULE_LICENSE("GPL");