LXR linux/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
  38enum max517_device_ids {
  39        ID_MAX517,
  40        ID_MAX518,
  41        ID_MAX519,
  42        ID_MAX520,
  43        ID_MAX521,
  44};
  45
  46struct 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 */
  56static 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
  79static 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
  99static 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
 117static 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
 124static 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
 131static 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
 137static const struct iio_info max517_info = {
 138        .read_raw = max517_read_raw,
 139        .write_raw = max517_write_raw,
 140        .driver_module = THIS_MODULE,
 141};
 142
 143#define MAX517_CHANNEL(chan) {                          \
 144        .type = IIO_VOLTAGE,                            \
 145        .indexed = 1,                                   \
 146        .output = 1,                                    \
 147        .channel = (chan),                              \
 148        .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |  \
 149        BIT(IIO_CHAN_INFO_SCALE),                       \
 150}
 151
 152static const struct iio_chan_spec max517_channels[] = {
 153        MAX517_CHANNEL(0),
 154        MAX517_CHANNEL(1),
 155        MAX517_CHANNEL(2),
 156        MAX517_CHANNEL(3),
 157        MAX517_CHANNEL(4),
 158        MAX517_CHANNEL(5),
 159        MAX517_CHANNEL(6),
 160        MAX517_CHANNEL(7),
 161};
 162
 163static int max517_probe(struct i2c_client *client,
 164                        const struct i2c_device_id *id)
 165{
 166        struct max517_data *data;
 167        struct iio_dev *indio_dev;
 168        struct max517_platform_data *platform_data = client->dev.platform_data;
 169        int chan;
 170
 171        indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
 172        if (!indio_dev)
 173                return -ENOMEM;
 174        data = iio_priv(indio_dev);
 175        i2c_set_clientdata(client, indio_dev);
 176        data->client = client;
 177
 178        /* establish that the iio_dev is a child of the i2c device */
 179        indio_dev->dev.parent = &client->dev;
 180
 181        switch (id->driver_data) {
 182        case ID_MAX521:
 183                indio_dev->num_channels = 8;
 184                break;
 185        case ID_MAX520:
 186                indio_dev->num_channels = 4;
 187                break;
 188        case ID_MAX519:
 189        case ID_MAX518:
 190                indio_dev->num_channels = 2;
 191                break;
 192        default:  /* single channel for MAX517 */
 193                indio_dev->num_channels = 1;
 194                break;
 195        }
 196        indio_dev->channels = max517_channels;
 197        indio_dev->modes = INDIO_DIRECT_MODE;
 198        indio_dev->info = &max517_info;
 199
 200        /*
 201         * Reference voltage on MAX518 and default is 5V, else take vref_mv
 202         * from platform_data
 203         */
 204        for (chan = 0; chan < indio_dev->num_channels; chan++) {
 205                if (id->driver_data == ID_MAX518 || !platform_data)
 206                        data->vref_mv[chan] = 5000; /* mV */
 207                else
 208                        data->vref_mv[chan] = platform_data->vref_mv[chan];
 209        }
 210
 211        return iio_device_register(indio_dev);
 212}
 213
 214static int max517_remove(struct i2c_client *client)
 215{
 216        iio_device_unregister(i2c_get_clientdata(client));
 217        return 0;
 218}
 219
 220static const struct i2c_device_id max517_id[] = {
 221        { "max517", ID_MAX517 },
 222        { "max518", ID_MAX518 },
 223        { "max519", ID_MAX519 },
 224        { "max520", ID_MAX520 },
 225        { "max521", ID_MAX521 },
 226        { }
 227};
 228MODULE_DEVICE_TABLE(i2c, max517_id);
 229
 230static struct i2c_driver max517_driver = {
 231        .driver = {
 232                .name   = MAX517_DRV_NAME,
 233                .pm             = MAX517_PM_OPS,
 234        },
 235        .probe          = max517_probe,
 236        .remove         = max517_remove,
 237        .id_table       = max517_id,
 238};
 239module_i2c_driver(max517_driver);
 240
 241MODULE_AUTHOR("Roland Stigge <stigge@antcom.de>");
 242MODULE_DESCRIPTION("MAX517/518/519/520/521 8-bit DAC");
 243MODULE_LICENSE("GPL");
 244