drivers/iio/dac/m62332.c

   1 /*
   2  *  m62332.c - Support for Mitsubishi m62332 DAC
   3  *
   4  *  Copyright (c) 2014 Dmitry Eremin-Solenikov
   5  *
   6  *  Based on max517 driver:
   7  *  Copyright (C) 2010, 2011 Roland Stigge <stigge@antcom.de>
   8  *
   9  *  This program is free software; you can redistribute it and/or modify
  10  *  it under the terms of the GNU General Public License as published by
  11  *  the Free Software Foundation; either version 2 of the License, or
  12  *  (at your option) any later version.
  13  *
  14  *  This program is distributed in the hope that it will be useful,
  15  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17  *  GNU General Public License for more details.
  18  */
  19
  20 #include <linux/module.h>
  21 #include <linux/slab.h>
  22 #include <linux/i2c.h>
  23 #include <linux/err.h>
  24
  25 #include <linux/iio/iio.h>
  26 #include <linux/iio/driver.h>
  27
  28 #include <linux/regulator/consumer.h>
  29
  30 #define M62332_CHANNELS 2
  31
  32 struct m62332_data {
  33         struct i2c_client       *client;
  34         struct regulator        *vcc;
  35         struct mutex            mutex;
  36         u8                      raw[M62332_CHANNELS];
  37 #ifdef CONFIG_PM_SLEEP
  38         u8                      save[M62332_CHANNELS];
  39 #endif
  40 };
  41
  42 static int m62332_set_value(struct iio_dev *indio_dev, u8 val, int channel)
  43 {
  44         struct m62332_data *data = iio_priv(indio_dev);
  45         struct i2c_client *client = data->client;
  46         u8 outbuf[2];
  47         int res;
  48
  49         if (val == data->raw[channel])
  50                 return 0;
  51
  52         outbuf[0] = channel;
  53         outbuf[1] = val;
  54
  55         mutex_lock(&data->mutex);
  56
  57         if (val) {
  58                 res = regulator_enable(data->vcc);
  59                 if (res)
  60                         goto out;
  61         }
  62
  63         res = i2c_master_send(client, outbuf, ARRAY_SIZE(outbuf));
  64         if (res >= 0 && res != ARRAY_SIZE(outbuf))
  65                 res = -EIO;
  66         if (res < 0)
  67                 goto out;
  68
  69         data->raw[channel] = val;
  70
  71         if (!val)
  72                 regulator_disable(data->vcc);
  73
  74         mutex_unlock(&data->mutex);
  75
  76         return 0;
  77
  78 out:
  79         mutex_unlock(&data->mutex);
  80
  81         return res;
  82 }
  83
  84 static int m62332_read_raw(struct iio_dev *indio_dev,
  85                            struct iio_chan_spec const *chan,
  86                            int *val,
  87                            int *val2,
  88                            long mask)
  89 {
  90         struct m62332_data *data = iio_priv(indio_dev);
  91         int ret;
  92
  93         switch (mask) {
  94         case IIO_CHAN_INFO_SCALE:
  95                 /* Corresponds to Vref / 2^(bits) */
  96                 ret = regulator_get_voltage(data->vcc);
  97                 if (ret < 0)
  98                         return ret;
  99
 100                 *val = ret / 1000; /* mV */
 101                 *val2 = 8;
 102
 103                 return IIO_VAL_FRACTIONAL_LOG2;
 104         case IIO_CHAN_INFO_RAW:
 105                 *val = data->raw[chan->channel];
 106
 107                 return IIO_VAL_INT;
 108         case IIO_CHAN_INFO_OFFSET:
 109                 *val = 1;
 110
 111                 return IIO_VAL_INT;
 112         default:
 113                 break;
 114         }
 115
 116         return -EINVAL;
 117 }
 118
 119 static int m62332_write_raw(struct iio_dev *indio_dev,
 120                             struct iio_chan_spec const *chan, int val, int val2,
 121                             long mask)
 122 {
 123         switch (mask) {
 124         case IIO_CHAN_INFO_RAW:
 125                 if (val < 0 || val > 255)
 126                         return -EINVAL;
 127
 128                 return m62332_set_value(indio_dev, val, chan->channel);
 129         default:
 130                 break;
 131         }
 132
 133         return -EINVAL;
 134 }
 135
 136 #ifdef CONFIG_PM_SLEEP
 137 static int m62332_suspend(struct device *dev)
 138 {
 139         struct i2c_client *client = to_i2c_client(dev);
 140         struct iio_dev *indio_dev = i2c_get_clientdata(client);
 141         struct m62332_data *data = iio_priv(indio_dev);
 142         int ret;
 143
 144         data->save[0] = data->raw[0];
 145         data->save[1] = data->raw[1];
 146
 147         ret = m62332_set_value(indio_dev, 0, 0);
 148         if (ret < 0)
 149                 return ret;
 150
 151         return m62332_set_value(indio_dev, 0, 1);
 152 }
 153
 154 static int m62332_resume(struct device *dev)
 155 {
 156         struct i2c_client *client = to_i2c_client(dev);
 157         struct iio_dev *indio_dev = i2c_get_clientdata(client);
 158         struct m62332_data *data = iio_priv(indio_dev);
 159         int ret;
 160
 161         ret = m62332_set_value(indio_dev, data->save[0], 0);
 162         if (ret < 0)
 163                 return ret;
 164
 165         return m62332_set_value(indio_dev, data->save[1], 1);
 166 }
 167
 168 static SIMPLE_DEV_PM_OPS(m62332_pm_ops, m62332_suspend, m62332_resume);
 169 #define M62332_PM_OPS (&m62332_pm_ops)
 170 #else
 171 #define M62332_PM_OPS NULL
 172 #endif
 173
 174 static const struct iio_info m62332_info = {
 175         .read_raw = m62332_read_raw,
 176         .write_raw = m62332_write_raw,
 177         .driver_module = THIS_MODULE,
 178 };
 179
 180 #define M62332_CHANNEL(chan) {                                  \
 181         .type = IIO_VOLTAGE,                                    \
 182         .indexed = 1,                                           \
 183         .output = 1,                                            \
 184         .channel = (chan),                                      \
 185         .datasheet_name = "CH" #chan,                           \
 186         .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),           \
 187         .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) |  \
 188                                     BIT(IIO_CHAN_INFO_OFFSET),  \
 189 }
 190
 191 static const struct iio_chan_spec m62332_channels[M62332_CHANNELS] = {
 192         M62332_CHANNEL(0),
 193         M62332_CHANNEL(1)
 194 };
 195
 196 static int m62332_probe(struct i2c_client *client,
 197                         const struct i2c_device_id *id)
 198 {
 199         struct m62332_data *data;
 200         struct iio_dev *indio_dev;
 201         int ret;
 202
 203         indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
 204         if (!indio_dev)
 205                 return -ENOMEM;
 206
 207         data = iio_priv(indio_dev);
 208         i2c_set_clientdata(client, indio_dev);
 209         data->client = client;
 210
 211         mutex_init(&data->mutex);
 212
 213         data->vcc = devm_regulator_get(&client->dev, "VCC");
 214         if (IS_ERR(data->vcc))
 215                 return PTR_ERR(data->vcc);
 216
 217         /* establish that the iio_dev is a child of the i2c device */
 218         indio_dev->dev.parent = &client->dev;
 219
 220         indio_dev->num_channels = ARRAY_SIZE(m62332_channels);
 221         indio_dev->channels = m62332_channels;
 222         indio_dev->modes = INDIO_DIRECT_MODE;
 223         indio_dev->info = &m62332_info;
 224
 225         ret = iio_map_array_register(indio_dev, client->dev.platform_data);
 226         if (ret < 0)
 227                 return ret;
 228
 229         ret = iio_device_register(indio_dev);
 230         if (ret < 0)
 231                 goto err;
 232
 233         return 0;
 234
 235 err:
 236         iio_map_array_unregister(indio_dev);
 237
 238         return ret;
 239 }
 240
 241 static int m62332_remove(struct i2c_client *client)
 242 {
 243         struct iio_dev *indio_dev = i2c_get_clientdata(client);
 244
 245         iio_device_unregister(indio_dev);
 246         iio_map_array_unregister(indio_dev);
 247         m62332_set_value(indio_dev, 0, 0);
 248         m62332_set_value(indio_dev, 0, 1);
 249
 250         return 0;
 251 }
 252
 253 static const struct i2c_device_id m62332_id[] = {
 254         { "m62332", },
 255         { }
 256 };
 257 MODULE_DEVICE_TABLE(i2c, m62332_id);
 258
 259 static struct i2c_driver m62332_driver = {
 260         .driver = {
 261                 .name   = "m62332",
 262                 .pm     = M62332_PM_OPS,
 263         },
 264         .probe          = m62332_probe,
 265         .remove         = m62332_remove,
 266         .id_table       = m62332_id,
 267 };
 268 module_i2c_driver(m62332_driver);
 269
 270 MODULE_AUTHOR("Dmitry Eremin-Solenikov");
 271 MODULE_DESCRIPTION("M62332 8-bit DAC");
 272 MODULE_LICENSE("GPL v2");