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 };
  43
  44 struct max517_data {
  45         struct i2c_client       *client;
  46         unsigned short          vref_mv[2];
  47 };
  48
  49 /*
  50  * channel: bit 0: channel 1
  51  *          bit 1: channel 2
  52  * (this way, it's possible to set both channels at once)
  53  */
  54 static int max517_set_value(struct iio_dev *indio_dev,
  55         long val, int channel)
  56 {
  57         struct max517_data *data = iio_priv(indio_dev);
  58         struct i2c_client *client = data->client;
  59         u8 outbuf[2];
  60         int res;
  61
  62         if (val < 0 || val > 255)
  63                 return -EINVAL;
  64
  65         outbuf[0] = channel;
  66         outbuf[1] = val;
  67
  68         res = i2c_master_send(client, outbuf, 2);
  69         if (res < 0)
  70                 return res;
  71         else if (res != 2)
  72                 return -EIO;
  73         else
  74                 return 0;
  75 }
  76
  77 static int max517_read_raw(struct iio_dev *indio_dev,
  78                            struct iio_chan_spec const *chan,
  79                            int *val,
  80                            int *val2,
  81                            long m)
  82 {
  83         struct max517_data *data = iio_priv(indio_dev);
  84
  85         switch (m) {
  86         case IIO_CHAN_INFO_SCALE:
  87                 /* Corresponds to Vref / 2^(bits) */
  88                 *val = data->vref_mv[chan->channel];
  89                 *val2 = 8;
  90                 return IIO_VAL_FRACTIONAL_LOG2;
  91         default:
  92                 break;
  93         }
  94         return -EINVAL;
  95 }
  96
  97 static int max517_write_raw(struct iio_dev *indio_dev,
  98         struct iio_chan_spec const *chan, int val, int val2, long mask)
  99 {
 100         int ret;
 101
 102         switch (mask) {
 103         case IIO_CHAN_INFO_RAW:
 104                 ret = max517_set_value(indio_dev, val, chan->channel);
 105                 break;
 106         default:
 107                 ret = -EINVAL;
 108                 break;
 109         }
 110
 111         return ret;
 112 }
 113
 114 #ifdef CONFIG_PM_SLEEP
 115 static int max517_suspend(struct device *dev)
 116 {
 117         u8 outbuf = COMMAND_PD;
 118
 119         return i2c_master_send(to_i2c_client(dev), &outbuf, 1);
 120 }
 121
 122 static int max517_resume(struct device *dev)
 123 {
 124         u8 outbuf = 0;
 125
 126         return i2c_master_send(to_i2c_client(dev), &outbuf, 1);
 127 }
 128
 129 static SIMPLE_DEV_PM_OPS(max517_pm_ops, max517_suspend, max517_resume);
 130 #define MAX517_PM_OPS (&max517_pm_ops)
 131 #else
 132 #define MAX517_PM_OPS NULL
 133 #endif
 134
 135 static const struct iio_info max517_info = {
 136         .read_raw = max517_read_raw,
 137         .write_raw = max517_write_raw,
 138         .driver_module = THIS_MODULE,
 139 };
 140
 141 #define MAX517_CHANNEL(chan) {                          \
 142         .type = IIO_VOLTAGE,                            \
 143         .indexed = 1,                                   \
 144         .output = 1,                                    \
 145         .channel = (chan),                              \
 146         .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |  \
 147         BIT(IIO_CHAN_INFO_SCALE),                       \
 148 }
 149
 150 static const struct iio_chan_spec max517_channels[] = {
 151         MAX517_CHANNEL(0),
 152         MAX517_CHANNEL(1)
 153 };
 154
 155 static int max517_probe(struct i2c_client *client,
 156                         const struct i2c_device_id *id)
 157 {
 158         struct max517_data *data;
 159         struct iio_dev *indio_dev;
 160         struct max517_platform_data *platform_data = client->dev.platform_data;
 161
 162         indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
 163         if (!indio_dev)
 164                 return -ENOMEM;
 165         data = iio_priv(indio_dev);
 166         i2c_set_clientdata(client, indio_dev);
 167         data->client = client;
 168
 169         /* establish that the iio_dev is a child of the i2c device */
 170         indio_dev->dev.parent = &client->dev;
 171
 172         /* reduced channel set for MAX517 */
 173         if (id->driver_data == ID_MAX517)
 174                 indio_dev->num_channels = 1;
 175         else
 176                 indio_dev->num_channels = 2;
 177         indio_dev->channels = max517_channels;
 178         indio_dev->modes = INDIO_DIRECT_MODE;
 179         indio_dev->info = &max517_info;
 180
 181         /*
 182          * Reference voltage on MAX518 and default is 5V, else take vref_mv
 183          * from platform_data
 184          */
 185         if (id->driver_data == ID_MAX518 || !platform_data) {
 186                 data->vref_mv[0] = data->vref_mv[1] = 5000; /* mV */
 187         } else {
 188                 data->vref_mv[0] = platform_data->vref_mv[0];
 189                 data->vref_mv[1] = platform_data->vref_mv[1];
 190         }
 191
 192         return iio_device_register(indio_dev);
 193 }
 194
 195 static int max517_remove(struct i2c_client *client)
 196 {
 197         iio_device_unregister(i2c_get_clientdata(client));
 198         return 0;
 199 }
 200
 201 static const struct i2c_device_id max517_id[] = {
 202         { "max517", ID_MAX517 },
 203         { "max518", ID_MAX518 },
 204         { "max519", ID_MAX519 },
 205         { }
 206 };
 207 MODULE_DEVICE_TABLE(i2c, max517_id);
 208
 209 static struct i2c_driver max517_driver = {
 210         .driver = {
 211                 .name   = MAX517_DRV_NAME,
 212                 .pm             = MAX517_PM_OPS,
 213         },
 214         .probe          = max517_probe,
 215         .remove         = max517_remove,
 216         .id_table       = max517_id,
 217 };
 218 module_i2c_driver(max517_driver);
 219
 220 MODULE_AUTHOR("Roland Stigge <stigge@antcom.de>");
 221 MODULE_DESCRIPTION("MAX517/MAX518/MAX519 8-bit DAC");
 222 MODULE_LICENSE("GPL");