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 "dac.h"
  30
  31 #include "max517.h"
  32
  33 #define MAX517_DRV_NAME "max517"
  34
  35 /* Commands */
  36 #define COMMAND_CHANNEL0        0x00
  37 #define COMMAND_CHANNEL1        0x01 /* for MAX518 and MAX519 */
  38 #define COMMAND_PD              0x08 /* Power Down */
  39
  40 enum max517_device_ids {
  41         ID_MAX517,
  42         ID_MAX518,
  43         ID_MAX519,
  44 };
  45
  46 struct max517_data {
  47         struct iio_dev          *indio_dev;
  48         struct i2c_client       *client;
  49         unsigned short          vref_mv[2];
  50 };
  51
  52 /*
  53  * channel: bit 0: channel 1
  54  *          bit 1: channel 2
  55  * (this way, it's possible to set both channels at once)
  56  */
  57 static ssize_t max517_set_value(struct device *dev,
  58                                  struct device_attribute *attr,
  59                                  const char *buf, size_t count, int channel)
  60 {
  61         struct iio_dev *dev_info = dev_get_drvdata(dev);
  62         struct max517_data *data = iio_priv(dev_info);
  63         struct i2c_client *client = data->client;
  64         u8 outbuf[4]; /* 1x or 2x command + value */
  65         int outbuf_size = 0;
  66         int res;
  67         long val;
  68
  69         res = strict_strtol(buf, 10, &val);
  70
  71         if (res)
  72                 return res;
  73
  74         if (val < 0 || val > 255)
  75                 return -EINVAL;
  76
  77         if (channel & 1) {
  78                 outbuf[outbuf_size++] = COMMAND_CHANNEL0;
  79                 outbuf[outbuf_size++] = val;
  80         }
  81         if (channel & 2) {
  82                 outbuf[outbuf_size++] = COMMAND_CHANNEL1;
  83                 outbuf[outbuf_size++] = val;
  84         }
  85
  86         /*
  87          * At this point, there are always 1 or 2 two-byte commands in
  88          * outbuf. With 2 commands, the device can set two outputs
  89          * simultaneously, latching the values upon the end of the I2C
  90          * transfer.
  91          */
  92
  93         res = i2c_master_send(client, outbuf, outbuf_size);
  94         if (res < 0)
  95                 return res;
  96
  97         return count;
  98 }
  99
 100 static ssize_t max517_set_value_1(struct device *dev,
 101                                  struct device_attribute *attr,
 102                                  const char *buf, size_t count)
 103 {
 104         return max517_set_value(dev, attr, buf, count, 1);
 105 }
 106 static IIO_DEV_ATTR_OUT_RAW(1, max517_set_value_1, 0);
 107
 108 static ssize_t max517_set_value_2(struct device *dev,
 109                                  struct device_attribute *attr,
 110                                  const char *buf, size_t count)
 111 {
 112         return max517_set_value(dev, attr, buf, count, 2);
 113 }
 114 static IIO_DEV_ATTR_OUT_RAW(2, max517_set_value_2, 1);
 115
 116 static ssize_t max517_set_value_both(struct device *dev,
 117                                  struct device_attribute *attr,
 118                                  const char *buf, size_t count)
 119 {
 120         return max517_set_value(dev, attr, buf, count, 3);
 121 }
 122 static IIO_DEVICE_ATTR_NAMED(out1and2_raw, out1&2_raw, S_IWUSR, NULL,
 123                 max517_set_value_both, -1);
 124
 125 static ssize_t max517_show_scale(struct device *dev,
 126                                 struct device_attribute *attr,
 127                                 char *buf, int channel)
 128 {
 129         struct iio_dev *dev_info = dev_get_drvdata(dev);
 130         struct max517_data *data = iio_priv(dev_info);
 131         /* Corresponds to Vref / 2^(bits) */
 132         unsigned int scale_uv = (data->vref_mv[channel - 1] * 1000) >> 8;
 133
 134         return sprintf(buf, "%d.%03d\n", scale_uv / 1000, scale_uv % 1000);
 135 }
 136
 137 static ssize_t max517_show_scale1(struct device *dev,
 138                                 struct device_attribute *attr,
 139                                 char *buf)
 140 {
 141         return max517_show_scale(dev, attr, buf, 1);
 142 }
 143 static IIO_DEVICE_ATTR(out1_scale, S_IRUGO, max517_show_scale1, NULL, 0);
 144
 145 static ssize_t max517_show_scale2(struct device *dev,
 146                                 struct device_attribute *attr,
 147                                 char *buf)
 148 {
 149         return max517_show_scale(dev, attr, buf, 2);
 150 }
 151 static IIO_DEVICE_ATTR(out2_scale, S_IRUGO, max517_show_scale2, NULL, 0);
 152
 153 /* On MAX517 variant, we have one output */
 154 static struct attribute *max517_attributes[] = {
 155         &iio_dev_attr_out1_raw.dev_attr.attr,
 156         &iio_dev_attr_out1_scale.dev_attr.attr,
 157         NULL
 158 };
 159
 160 static struct attribute_group max517_attribute_group = {
 161         .attrs = max517_attributes,
 162 };
 163
 164 /* On MAX518 and MAX519 variant, we have two outputs */
 165 static struct attribute *max518_attributes[] = {
 166         &iio_dev_attr_out1_raw.dev_attr.attr,
 167         &iio_dev_attr_out1_scale.dev_attr.attr,
 168         &iio_dev_attr_out2_raw.dev_attr.attr,
 169         &iio_dev_attr_out2_scale.dev_attr.attr,
 170         &iio_dev_attr_out1and2_raw.dev_attr.attr,
 171         NULL
 172 };
 173
 174 static struct attribute_group max518_attribute_group = {
 175         .attrs = max518_attributes,
 176 };
 177
 178 static int max517_suspend(struct i2c_client *client, pm_message_t mesg)
 179 {
 180         u8 outbuf = COMMAND_PD;
 181
 182         return i2c_master_send(client, &outbuf, 1);
 183 }
 184
 185 static int max517_resume(struct i2c_client *client)
 186 {
 187         u8 outbuf = 0;
 188
 189         return i2c_master_send(client, &outbuf, 1);
 190 }
 191
 192 static const struct iio_info max517_info = {
 193         .attrs = &max517_attribute_group,
 194         .driver_module = THIS_MODULE,
 195 };
 196
 197 static const struct iio_info max518_info = {
 198         .attrs = &max518_attribute_group,
 199         .driver_module = THIS_MODULE,
 200 };
 201
 202 static int max517_probe(struct i2c_client *client,
 203                         const struct i2c_device_id *id)
 204 {
 205         struct max517_data *data;
 206         struct iio_dev *indio_dev;
 207         struct max517_platform_data *platform_data = client->dev.platform_data;
 208         int err;
 209
 210         indio_dev = iio_allocate_device(sizeof(*data));
 211         if (indio_dev == NULL) {
 212                 err = -ENOMEM;
 213                 goto exit;
 214         }
 215         data = iio_priv(indio_dev);
 216         i2c_set_clientdata(client, indio_dev);
 217         data->client = client;
 218
 219         /* establish that the iio_dev is a child of the i2c device */
 220         indio_dev->dev.parent = &client->dev;
 221
 222         /* reduced attribute set for MAX517 */
 223         if (id->driver_data == ID_MAX517)
 224                 indio_dev->info = &max517_info;
 225         else
 226                 indio_dev->info = &max518_info;
 227         indio_dev->modes = INDIO_DIRECT_MODE;
 228
 229         /*
 230          * Reference voltage on MAX518 and default is 5V, else take vref_mv
 231          * from platform_data
 232          */
 233         if (id->driver_data == ID_MAX518 || !platform_data) {
 234                 data->vref_mv[0] = data->vref_mv[1] = 5000; /* mV */
 235         } else {
 236                 data->vref_mv[0] = platform_data->vref_mv[0];
 237                 data->vref_mv[1] = platform_data->vref_mv[1];
 238         }
 239
 240         err = iio_device_register(indio_dev);
 241         if (err)
 242                 goto exit_free_device;
 243
 244         dev_info(&client->dev, "DAC registered\n");
 245
 246         return 0;
 247
 248 exit_free_device:
 249         iio_free_device(indio_dev);
 250 exit:
 251         return err;
 252 }
 253
 254 static int max517_remove(struct i2c_client *client)
 255 {
 256         iio_free_device(i2c_get_clientdata(client));
 257
 258         return 0;
 259 }
 260
 261 static const struct i2c_device_id max517_id[] = {
 262         { "max517", ID_MAX517 },
 263         { "max518", ID_MAX518 },
 264         { "max519", ID_MAX519 },
 265         { }
 266 };
 267 MODULE_DEVICE_TABLE(i2c, max517_id);
 268
 269 static struct i2c_driver max517_driver = {
 270         .driver = {
 271                 .name   = MAX517_DRV_NAME,
 272         },
 273         .probe          = max517_probe,
 274         .remove         = max517_remove,
 275         .suspend        = max517_suspend,
 276         .resume         = max517_resume,
 277         .id_table       = max517_id,
 278 };
 279
 280 static int __init max517_init(void)
 281 {
 282         return i2c_add_driver(&max517_driver);
 283 }
 284
 285 static void __exit max517_exit(void)
 286 {
 287         i2c_del_driver(&max517_driver);
 288 }
 289
 290 MODULE_AUTHOR("Roland Stigge <stigge@antcom.de>");
 291 MODULE_DESCRIPTION("MAX517/MAX518/MAX519 8-bit DAC");
 292 MODULE_LICENSE("GPL");
 293
 294 module_init(max517_init);
 295 module_exit(max517_exit);