drivers/staging/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 "../iio.h"
  29 #include "../sysfs.h"
  30 #include "dac.h"
  31
  32 #include "max517.h"
  33
  34 #define MAX517_DRV_NAME "max517"
  35
  36 /* Commands */
  37 #define COMMAND_CHANNEL0        0x00
  38 #define COMMAND_CHANNEL1        0x01 /* for MAX518 and MAX519 */
  39 #define COMMAND_PD              0x08 /* Power Down */
  40
  41 enum max517_device_ids {
  42         ID_MAX517,
  43         ID_MAX518,
  44         ID_MAX519,
  45 };
  46
  47 struct max517_data {
  48         struct iio_dev          *indio_dev;
  49         struct i2c_client       *client;
  50         unsigned short          vref_mv[2];
  51 };
  52
  53 /*
  54  * channel: bit 0: channel 1
  55  *          bit 1: channel 2
  56  * (this way, it's possible to set both channels at once)
  57  */
  58 static ssize_t max517_set_value(struct device *dev,
  59                                  struct device_attribute *attr,
  60                                  const char *buf, size_t count, int channel)
  61 {
  62         struct iio_dev *indio_dev = dev_get_drvdata(dev);
  63         struct max517_data *data = iio_priv(indio_dev);
  64         struct i2c_client *client = data->client;
  65         u8 outbuf[4]; /* 1x or 2x command + value */
  66         int outbuf_size = 0;
  67         int res;
  68         long val;
  69
  70         res = strict_strtol(buf, 10, &val);
  71
  72         if (res)
  73                 return res;
  74
  75         if (val < 0 || val > 255)
  76                 return -EINVAL;
  77
  78         if (channel & 1) {
  79                 outbuf[outbuf_size++] = COMMAND_CHANNEL0;
  80                 outbuf[outbuf_size++] = val;
  81         }
  82         if (channel & 2) {
  83                 outbuf[outbuf_size++] = COMMAND_CHANNEL1;
  84                 outbuf[outbuf_size++] = val;
  85         }
  86
  87         /*
  88          * At this point, there are always 1 or 2 two-byte commands in
  89          * outbuf. With 2 commands, the device can set two outputs
  90          * simultaneously, latching the values upon the end of the I2C
  91          * transfer.
  92          */
  93
  94         res = i2c_master_send(client, outbuf, outbuf_size);
  95         if (res < 0)
  96                 return res;
  97
  98         return count;
  99 }
 100
 101 static ssize_t max517_set_value_1(struct device *dev,
 102                                  struct device_attribute *attr,
 103                                  const char *buf, size_t count)
 104 {
 105         return max517_set_value(dev, attr, buf, count, 1);
 106 }
 107 static IIO_DEV_ATTR_OUT_RAW(1, max517_set_value_1, 0);
 108
 109 static ssize_t max517_set_value_2(struct device *dev,
 110                                  struct device_attribute *attr,
 111                                  const char *buf, size_t count)
 112 {
 113         return max517_set_value(dev, attr, buf, count, 2);
 114 }
 115 static IIO_DEV_ATTR_OUT_RAW(2, max517_set_value_2, 1);
 116
 117 static ssize_t max517_set_value_both(struct device *dev,
 118                                  struct device_attribute *attr,
 119                                  const char *buf, size_t count)
 120 {
 121         return max517_set_value(dev, attr, buf, count, 3);
 122 }
 123 static IIO_DEVICE_ATTR_NAMED(out_voltage1and2_raw,
 124                              out_voltage1&2_raw, S_IWUSR, NULL,
 125                              max517_set_value_both, -1);
 126
 127 static ssize_t max517_show_scale(struct device *dev,
 128                                 struct device_attribute *attr,
 129                                 char *buf, int channel)
 130 {
 131         struct iio_dev *indio_dev = dev_get_drvdata(dev);
 132         struct max517_data *data = iio_priv(indio_dev);
 133         /* Corresponds to Vref / 2^(bits) */
 134         unsigned int scale_uv = (data->vref_mv[channel - 1] * 1000) >> 8;
 135
 136         return sprintf(buf, "%d.%03d\n", scale_uv / 1000, scale_uv % 1000);
 137 }
 138
 139 static ssize_t max517_show_scale1(struct device *dev,
 140                                 struct device_attribute *attr,
 141                                 char *buf)
 142 {
 143         return max517_show_scale(dev, attr, buf, 1);
 144 }
 145 static IIO_DEVICE_ATTR(out_voltage1_scale, S_IRUGO,
 146                        max517_show_scale1, NULL, 0);
 147
 148 static ssize_t max517_show_scale2(struct device *dev,
 149                                 struct device_attribute *attr,
 150                                 char *buf)
 151 {
 152         return max517_show_scale(dev, attr, buf, 2);
 153 }
 154 static IIO_DEVICE_ATTR(out_voltage2_scale, S_IRUGO,
 155                        max517_show_scale2, NULL, 0);
 156
 157 /* On MAX517 variant, we have one output */
 158 static struct attribute *max517_attributes[] = {
 159         &iio_dev_attr_out_voltage1_raw.dev_attr.attr,
 160         &iio_dev_attr_out_voltage1_scale.dev_attr.attr,
 161         NULL
 162 };
 163
 164 static struct attribute_group max517_attribute_group = {
 165         .attrs = max517_attributes,
 166 };
 167
 168 /* On MAX518 and MAX519 variant, we have two outputs */
 169 static struct attribute *max518_attributes[] = {
 170         &iio_dev_attr_out_voltage1_raw.dev_attr.attr,
 171         &iio_dev_attr_out_voltage1_scale.dev_attr.attr,
 172         &iio_dev_attr_out_voltage2_raw.dev_attr.attr,
 173         &iio_dev_attr_out_voltage2_scale.dev_attr.attr,
 174         &iio_dev_attr_out_voltage1and2_raw.dev_attr.attr,
 175         NULL
 176 };
 177
 178 static struct attribute_group max518_attribute_group = {
 179         .attrs = max518_attributes,
 180 };
 181
 182 static int max517_suspend(struct i2c_client *client, pm_message_t mesg)
 183 {
 184         u8 outbuf = COMMAND_PD;
 185
 186         return i2c_master_send(client, &outbuf, 1);
 187 }
 188
 189 static int max517_resume(struct i2c_client *client)
 190 {
 191         u8 outbuf = 0;
 192
 193         return i2c_master_send(client, &outbuf, 1);
 194 }
 195
 196 static const struct iio_info max517_info = {
 197         .attrs = &max517_attribute_group,
 198         .driver_module = THIS_MODULE,
 199 };
 200
 201 static const struct iio_info max518_info = {
 202         .attrs = &max518_attribute_group,
 203         .driver_module = THIS_MODULE,
 204 };
 205
 206 static int max517_probe(struct i2c_client *client,
 207                         const struct i2c_device_id *id)
 208 {
 209         struct max517_data *data;
 210         struct iio_dev *indio_dev;
 211         struct max517_platform_data *platform_data = client->dev.platform_data;
 212         int err;
 213
 214         indio_dev = iio_allocate_device(sizeof(*data));
 215         if (indio_dev == NULL) {
 216                 err = -ENOMEM;
 217                 goto exit;
 218         }
 219         data = iio_priv(indio_dev);
 220         i2c_set_clientdata(client, indio_dev);
 221         data->client = client;
 222
 223         /* establish that the iio_dev is a child of the i2c device */
 224         indio_dev->dev.parent = &client->dev;
 225
 226         /* reduced attribute set for MAX517 */
 227         if (id->driver_data == ID_MAX517)
 228                 indio_dev->info = &max517_info;
 229         else
 230                 indio_dev->info = &max518_info;
 231         indio_dev->modes = INDIO_DIRECT_MODE;
 232
 233         /*
 234          * Reference voltage on MAX518 and default is 5V, else take vref_mv
 235          * from platform_data
 236          */
 237         if (id->driver_data == ID_MAX518 || !platform_data) {
 238                 data->vref_mv[0] = data->vref_mv[1] = 5000; /* mV */
 239         } else {
 240                 data->vref_mv[0] = platform_data->vref_mv[0];
 241                 data->vref_mv[1] = platform_data->vref_mv[1];
 242         }
 243
 244         err = iio_device_register(indio_dev);
 245         if (err)
 246                 goto exit_free_device;
 247
 248         dev_info(&client->dev, "DAC registered\n");
 249
 250         return 0;
 251
 252 exit_free_device:
 253         iio_free_device(indio_dev);
 254 exit:
 255         return err;
 256 }
 257
 258 static int max517_remove(struct i2c_client *client)
 259 {
 260         iio_free_device(i2c_get_clientdata(client));
 261
 262         return 0;
 263 }
 264
 265 static const struct i2c_device_id max517_id[] = {
 266         { "max517", ID_MAX517 },
 267         { "max518", ID_MAX518 },
 268         { "max519", ID_MAX519 },
 269         { }
 270 };
 271 MODULE_DEVICE_TABLE(i2c, max517_id);
 272
 273 static struct i2c_driver max517_driver = {
 274         .driver = {
 275                 .name   = MAX517_DRV_NAME,
 276         },
 277         .probe          = max517_probe,
 278         .remove         = max517_remove,
 279         .suspend        = max517_suspend,
 280         .resume         = max517_resume,
 281         .id_table       = max517_id,
 282 };
 283 module_i2c_driver(max517_driver);
 284
 285 MODULE_AUTHOR("Roland Stigge <stigge@antcom.de>");
 286 MODULE_DESCRIPTION("MAX517/MAX518/MAX519 8-bit DAC");
 287 MODULE_LICENSE("GPL");