drivers/hwmon/adcxx.c

   1 /*
   2  * adcxx.c
   3  *
   4  * The adcxx4s is an AD converter family from National Semiconductor (NS).
   5  *
   6  * Copyright (c) 2008 Marc Pignat <marc.pignat@hevs.ch>
   7  *
   8  * The adcxx4s communicates with a host processor via an SPI/Microwire Bus
   9  * interface. This driver supports the whole family of devices with name
  10  * ADC<bb><c>S<sss>, where
  11  * * bb is the resolution in number of bits (8, 10, 12)
  12  * * c is the number of channels (1, 2, 4, 8)
  13  * * sss is the maximum conversion speed (021 for 200 kSPS, 051 for 500 kSPS
  14  *   and 101 for 1 MSPS)
  15  *
  16  * Complete datasheets are available at National's website here:
  17  * http://www.national.com/ds/DC/ADC<bb><c>S<sss>.pdf
  18  *
  19  * Handling of 8, 10 and 12 bits converters are the same, the
  20  * unavailable bits are 0 :)
  21  *
  22  * This program is free software; you can redistribute it and/or modify
  23  * it under the terms of the GNU General Public License as published by
  24  * the Free Software Foundation; either version 2 of the License, or
  25  * (at your option) any later version.
  26  *
  27  * This program is distributed in the hope that it will be useful,
  28  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  29  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  30  * GNU General Public License for more details.
  31  *
  32  * You should have received a copy of the GNU General Public License
  33  * along with this program; if not, write to the Free Software
  34  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  35  */
  36
  37 #include <linux/init.h>
  38 #include <linux/module.h>
  39 #include <linux/kernel.h>
  40 #include <linux/device.h>
  41 #include <linux/err.h>
  42 #include <linux/sysfs.h>
  43 #include <linux/hwmon.h>
  44 #include <linux/hwmon-sysfs.h>
  45 #include <linux/mutex.h>
  46 #include <linux/spi/spi.h>
  47
  48 #define DRVNAME         "adcxx"
  49
  50 struct adcxx {
  51         struct device *hwmon_dev;
  52         struct mutex lock;
  53         u32 channels;
  54         u32 reference; /* in millivolts */
  55 };
  56
  57 /* sysfs hook function */
  58 static ssize_t adcxx_read(struct device *dev,
  59                 struct device_attribute *devattr, char *buf)
  60 {
  61         struct spi_device *spi = to_spi_device(dev);
  62         struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
  63         struct adcxx *adc = dev_get_drvdata(&spi->dev);
  64         u8 tx_buf[2] = { attr->index << 3 }; /* other bits are don't care */
  65         u8 rx_buf[2];
  66         int status;
  67         int value;
  68
  69         if (mutex_lock_interruptible(&adc->lock))
  70                 return -ERESTARTSYS;
  71
  72         status = spi_write_then_read(spi, tx_buf, sizeof(tx_buf),
  73                                         rx_buf, sizeof(rx_buf));
  74         if (status < 0) {
  75                 dev_warn(dev, "spi_write_then_read failed with status %d\n",
  76                                 status);
  77                 goto out;
  78         }
  79
  80         value = (rx_buf[0] << 8) + rx_buf[1];
  81         dev_dbg(dev, "raw value = 0x%x\n", value);
  82
  83         value = value * adc->reference >> 12;
  84         status = sprintf(buf, "%d\n", value);
  85 out:
  86         mutex_unlock(&adc->lock);
  87         return status;
  88 }
  89
  90 static ssize_t adcxx_show_min(struct device *dev,
  91                 struct device_attribute *devattr, char *buf)
  92 {
  93         /* The minimum reference is 0 for this chip family */
  94         return sprintf(buf, "0\n");
  95 }
  96
  97 static ssize_t adcxx_show_max(struct device *dev,
  98                 struct device_attribute *devattr, char *buf)
  99 {
 100         struct spi_device *spi = to_spi_device(dev);
 101         struct adcxx *adc = dev_get_drvdata(&spi->dev);
 102         u32 reference;
 103
 104         if (mutex_lock_interruptible(&adc->lock))
 105                 return -ERESTARTSYS;
 106
 107         reference = adc->reference;
 108
 109         mutex_unlock(&adc->lock);
 110
 111         return sprintf(buf, "%d\n", reference);
 112 }
 113
 114 static ssize_t adcxx_set_max(struct device *dev,
 115         struct device_attribute *devattr, const char *buf, size_t count)
 116 {
 117         struct spi_device *spi = to_spi_device(dev);
 118         struct adcxx *adc = dev_get_drvdata(&spi->dev);
 119         unsigned long value;
 120
 121         if (strict_strtoul(buf, 10, &value))
 122                 return -EINVAL;
 123
 124         if (mutex_lock_interruptible(&adc->lock))
 125                 return -ERESTARTSYS;
 126
 127         adc->reference = value;
 128
 129         mutex_unlock(&adc->lock);
 130
 131         return count;
 132 }
 133
 134 static ssize_t adcxx_show_name(struct device *dev, struct device_attribute
 135                               *devattr, char *buf)
 136 {
 137         struct spi_device *spi = to_spi_device(dev);
 138         struct adcxx *adc = dev_get_drvdata(&spi->dev);
 139
 140         return sprintf(buf, "adcxx%ds\n", adc->channels);
 141 }
 142
 143 static struct sensor_device_attribute ad_input[] = {
 144         SENSOR_ATTR(name, S_IRUGO, adcxx_show_name, NULL, 0),
 145         SENSOR_ATTR(in_min, S_IRUGO, adcxx_show_min, NULL, 0),
 146         SENSOR_ATTR(in_max, S_IWUSR | S_IRUGO, adcxx_show_max,
 147                                         adcxx_set_max, 0),
 148         SENSOR_ATTR(in0_input, S_IRUGO, adcxx_read, NULL, 0),
 149         SENSOR_ATTR(in1_input, S_IRUGO, adcxx_read, NULL, 1),
 150         SENSOR_ATTR(in2_input, S_IRUGO, adcxx_read, NULL, 2),
 151         SENSOR_ATTR(in3_input, S_IRUGO, adcxx_read, NULL, 3),
 152         SENSOR_ATTR(in4_input, S_IRUGO, adcxx_read, NULL, 4),
 153         SENSOR_ATTR(in5_input, S_IRUGO, adcxx_read, NULL, 5),
 154         SENSOR_ATTR(in6_input, S_IRUGO, adcxx_read, NULL, 6),
 155         SENSOR_ATTR(in7_input, S_IRUGO, adcxx_read, NULL, 7),
 156 };
 157
 158 /*----------------------------------------------------------------------*/
 159
 160 static int __devinit adcxx_probe(struct spi_device *spi, int channels)
 161 {
 162         struct adcxx *adc;
 163         int status;
 164         int i;
 165
 166         adc = kzalloc(sizeof *adc, GFP_KERNEL);
 167         if (!adc)
 168                 return -ENOMEM;
 169
 170         /* set a default value for the reference */
 171         adc->reference = 3300;
 172         adc->channels = channels;
 173         mutex_init(&adc->lock);
 174
 175         mutex_lock(&adc->lock);
 176
 177         dev_set_drvdata(&spi->dev, adc);
 178
 179         for (i = 0; i < 3 + adc->channels; i++) {
 180                 status = device_create_file(&spi->dev, &ad_input[i].dev_attr);
 181                 if (status) {
 182                         dev_err(&spi->dev, "device_create_file failed.\n");
 183                         goto out_err;
 184                 }
 185         }
 186
 187         adc->hwmon_dev = hwmon_device_register(&spi->dev);
 188         if (IS_ERR(adc->hwmon_dev)) {
 189                 dev_err(&spi->dev, "hwmon_device_register failed.\n");
 190                 status = PTR_ERR(adc->hwmon_dev);
 191                 goto out_err;
 192         }
 193
 194         mutex_unlock(&adc->lock);
 195         return 0;
 196
 197 out_err:
 198         for (i--; i >= 0; i--)
 199                 device_remove_file(&spi->dev, &ad_input[i].dev_attr);
 200
 201         dev_set_drvdata(&spi->dev, NULL);
 202         mutex_unlock(&adc->lock);
 203         kfree(adc);
 204         return status;
 205 }
 206
 207 static int __devinit adcxx1s_probe(struct spi_device *spi)
 208 {
 209         return adcxx_probe(spi, 1);
 210 }
 211
 212 static int __devinit adcxx2s_probe(struct spi_device *spi)
 213 {
 214         return adcxx_probe(spi, 2);
 215 }
 216
 217 static int __devinit adcxx4s_probe(struct spi_device *spi)
 218 {
 219         return adcxx_probe(spi, 4);
 220 }
 221
 222 static int __devinit adcxx8s_probe(struct spi_device *spi)
 223 {
 224         return adcxx_probe(spi, 8);
 225 }
 226
 227 static int __devexit adcxx_remove(struct spi_device *spi)
 228 {
 229         struct adcxx *adc = dev_get_drvdata(&spi->dev);
 230         int i;
 231
 232         mutex_lock(&adc->lock);
 233         hwmon_device_unregister(adc->hwmon_dev);
 234         for (i = 0; i < 3 + adc->channels; i++)
 235                 device_remove_file(&spi->dev, &ad_input[i].dev_attr);
 236
 237         dev_set_drvdata(&spi->dev, NULL);
 238         mutex_unlock(&adc->lock);
 239         kfree(adc);
 240
 241         return 0;
 242 }
 243
 244 static struct spi_driver adcxx1s_driver = {
 245         .driver = {
 246                 .name   = "adcxx1s",
 247                 .owner  = THIS_MODULE,
 248         },
 249         .probe  = adcxx1s_probe,
 250         .remove = __devexit_p(adcxx_remove),
 251 };
 252
 253 static struct spi_driver adcxx2s_driver = {
 254         .driver = {
 255                 .name   = "adcxx2s",
 256                 .owner  = THIS_MODULE,
 257         },
 258         .probe  = adcxx2s_probe,
 259         .remove = __devexit_p(adcxx_remove),
 260 };
 261
 262 static struct spi_driver adcxx4s_driver = {
 263         .driver = {
 264                 .name   = "adcxx4s",
 265                 .owner  = THIS_MODULE,
 266         },
 267         .probe  = adcxx4s_probe,
 268         .remove = __devexit_p(adcxx_remove),
 269 };
 270
 271 static struct spi_driver adcxx8s_driver = {
 272         .driver = {
 273                 .name   = "adcxx8s",
 274                 .owner  = THIS_MODULE,
 275         },
 276         .probe  = adcxx8s_probe,
 277         .remove = __devexit_p(adcxx_remove),
 278 };
 279
 280 static int __init init_adcxx(void)
 281 {
 282         int status;
 283         status = spi_register_driver(&adcxx1s_driver);
 284         if (status)
 285                 goto reg_1_failed;
 286
 287         status = spi_register_driver(&adcxx2s_driver);
 288         if (status)
 289                 goto reg_2_failed;
 290
 291         status = spi_register_driver(&adcxx4s_driver);
 292         if (status)
 293                 goto reg_4_failed;
 294
 295         status = spi_register_driver(&adcxx8s_driver);
 296         if (status)
 297                 goto reg_8_failed;
 298
 299         return status;
 300
 301 reg_8_failed:
 302         spi_unregister_driver(&adcxx4s_driver);
 303 reg_4_failed:
 304         spi_unregister_driver(&adcxx2s_driver);
 305 reg_2_failed:
 306         spi_unregister_driver(&adcxx1s_driver);
 307 reg_1_failed:
 308         return status;
 309 }
 310
 311 static void __exit exit_adcxx(void)
 312 {
 313         spi_unregister_driver(&adcxx1s_driver);
 314         spi_unregister_driver(&adcxx2s_driver);
 315         spi_unregister_driver(&adcxx4s_driver);
 316         spi_unregister_driver(&adcxx8s_driver);
 317 }
 318
 319 module_init(init_adcxx);
 320 module_exit(exit_adcxx);
 321
 322 MODULE_AUTHOR("Marc Pignat");
 323 MODULE_DESCRIPTION("National Semiconductor adcxx8sxxx Linux driver");
 324 MODULE_LICENSE("GPL");
 325
 326 MODULE_ALIAS("adcxx1s");
 327 MODULE_ALIAS("adcxx2s");
 328 MODULE_ALIAS("adcxx4s");
 329 MODULE_ALIAS("adcxx8s");