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/mod_devicetable.h>
  47 #include <linux/spi/spi.h>
  48
  49 #define DRVNAME         "adcxx"
  50
  51 struct adcxx {
  52         struct device *hwmon_dev;
  53         struct mutex lock;
  54         u32 channels;
  55         u32 reference; /* in millivolts */
  56 };
  57
  58 /* sysfs hook function */
  59 static ssize_t adcxx_read(struct device *dev,
  60                 struct device_attribute *devattr, char *buf)
  61 {
  62         struct spi_device *spi = to_spi_device(dev);
  63         struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
  64         struct adcxx *adc = dev_get_drvdata(&spi->dev);
  65         u8 tx_buf[2] = { attr->index << 3 }; /* other bits are don't care */
  66         u8 rx_buf[2];
  67         int status;
  68         int value;
  69
  70         if (mutex_lock_interruptible(&adc->lock))
  71                 return -ERESTARTSYS;
  72
  73         status = spi_write_then_read(spi, tx_buf, sizeof(tx_buf),
  74                                         rx_buf, sizeof(rx_buf));
  75         if (status < 0) {
  76                 dev_warn(dev, "spi_write_then_read failed with status %d\n",
  77                                 status);
  78                 goto out;
  79         }
  80
  81         value = (rx_buf[0] << 8) + rx_buf[1];
  82         dev_dbg(dev, "raw value = 0x%x\n", value);
  83
  84         value = value * adc->reference >> 12;
  85         status = sprintf(buf, "%d\n", value);
  86 out:
  87         mutex_unlock(&adc->lock);
  88         return status;
  89 }
  90
  91 static ssize_t adcxx_show_min(struct device *dev,
  92                 struct device_attribute *devattr, char *buf)
  93 {
  94         /* The minimum reference is 0 for this chip family */
  95         return sprintf(buf, "0\n");
  96 }
  97
  98 static ssize_t adcxx_show_max(struct device *dev,
  99                 struct device_attribute *devattr, char *buf)
 100 {
 101         struct spi_device *spi = to_spi_device(dev);
 102         struct adcxx *adc = dev_get_drvdata(&spi->dev);
 103         u32 reference;
 104
 105         if (mutex_lock_interruptible(&adc->lock))
 106                 return -ERESTARTSYS;
 107
 108         reference = adc->reference;
 109
 110         mutex_unlock(&adc->lock);
 111
 112         return sprintf(buf, "%d\n", reference);
 113 }
 114
 115 static ssize_t adcxx_set_max(struct device *dev,
 116         struct device_attribute *devattr, const char *buf, size_t count)
 117 {
 118         struct spi_device *spi = to_spi_device(dev);
 119         struct adcxx *adc = dev_get_drvdata(&spi->dev);
 120         unsigned long value;
 121
 122         if (strict_strtoul(buf, 10, &value))
 123                 return -EINVAL;
 124
 125         if (mutex_lock_interruptible(&adc->lock))
 126                 return -ERESTARTSYS;
 127
 128         adc->reference = value;
 129
 130         mutex_unlock(&adc->lock);
 131
 132         return count;
 133 }
 134
 135 static ssize_t adcxx_show_name(struct device *dev, struct device_attribute
 136                               *devattr, char *buf)
 137 {
 138         struct spi_device *spi = to_spi_device(dev);
 139         struct adcxx *adc = dev_get_drvdata(&spi->dev);
 140
 141         return sprintf(buf, "adcxx%ds\n", adc->channels);
 142 }
 143
 144 static struct sensor_device_attribute ad_input[] = {
 145         SENSOR_ATTR(name, S_IRUGO, adcxx_show_name, NULL, 0),
 146         SENSOR_ATTR(in_min, S_IRUGO, adcxx_show_min, NULL, 0),
 147         SENSOR_ATTR(in_max, S_IWUSR | S_IRUGO, adcxx_show_max,
 148                                         adcxx_set_max, 0),
 149         SENSOR_ATTR(in0_input, S_IRUGO, adcxx_read, NULL, 0),
 150         SENSOR_ATTR(in1_input, S_IRUGO, adcxx_read, NULL, 1),
 151         SENSOR_ATTR(in2_input, S_IRUGO, adcxx_read, NULL, 2),
 152         SENSOR_ATTR(in3_input, S_IRUGO, adcxx_read, NULL, 3),
 153         SENSOR_ATTR(in4_input, S_IRUGO, adcxx_read, NULL, 4),
 154         SENSOR_ATTR(in5_input, S_IRUGO, adcxx_read, NULL, 5),
 155         SENSOR_ATTR(in6_input, S_IRUGO, adcxx_read, NULL, 6),
 156         SENSOR_ATTR(in7_input, S_IRUGO, adcxx_read, NULL, 7),
 157 };
 158
 159 /*----------------------------------------------------------------------*/
 160
 161 static int __devinit adcxx_probe(struct spi_device *spi)
 162 {
 163         int channels = spi_get_device_id(spi)->driver_data;
 164         struct adcxx *adc;
 165         int status;
 166         int i;
 167
 168         adc = kzalloc(sizeof *adc, GFP_KERNEL);
 169         if (!adc)
 170                 return -ENOMEM;
 171
 172         /* set a default value for the reference */
 173         adc->reference = 3300;
 174         adc->channels = channels;
 175         mutex_init(&adc->lock);
 176
 177         mutex_lock(&adc->lock);
 178
 179         dev_set_drvdata(&spi->dev, adc);
 180
 181         for (i = 0; i < 3 + adc->channels; i++) {
 182                 status = device_create_file(&spi->dev, &ad_input[i].dev_attr);
 183                 if (status) {
 184                         dev_err(&spi->dev, "device_create_file failed.\n");
 185                         goto out_err;
 186                 }
 187         }
 188
 189         adc->hwmon_dev = hwmon_device_register(&spi->dev);
 190         if (IS_ERR(adc->hwmon_dev)) {
 191                 dev_err(&spi->dev, "hwmon_device_register failed.\n");
 192                 status = PTR_ERR(adc->hwmon_dev);
 193                 goto out_err;
 194         }
 195
 196         mutex_unlock(&adc->lock);
 197         return 0;
 198
 199 out_err:
 200         for (i--; i >= 0; i--)
 201                 device_remove_file(&spi->dev, &ad_input[i].dev_attr);
 202
 203         dev_set_drvdata(&spi->dev, NULL);
 204         mutex_unlock(&adc->lock);
 205         kfree(adc);
 206         return status;
 207 }
 208
 209 static int __devexit adcxx_remove(struct spi_device *spi)
 210 {
 211         struct adcxx *adc = dev_get_drvdata(&spi->dev);
 212         int i;
 213
 214         mutex_lock(&adc->lock);
 215         hwmon_device_unregister(adc->hwmon_dev);
 216         for (i = 0; i < 3 + adc->channels; i++)
 217                 device_remove_file(&spi->dev, &ad_input[i].dev_attr);
 218
 219         dev_set_drvdata(&spi->dev, NULL);
 220         mutex_unlock(&adc->lock);
 221         kfree(adc);
 222
 223         return 0;
 224 }
 225
 226 static const struct spi_device_id adcxx_ids[] = {
 227         { "adcxx1s", 1 },
 228         { "adcxx2s", 2 },
 229         { "adcxx4s", 4 },
 230         { "adcxx8s", 8 },
 231         { },
 232 };
 233 MODULE_DEVICE_TABLE(spi, adcxx_ids);
 234
 235 static struct spi_driver adcxx_driver = {
 236         .driver = {
 237                 .name   = "adcxx",
 238                 .owner  = THIS_MODULE,
 239         },
 240         .id_table = adcxx_ids,
 241         .probe  = adcxx_probe,
 242         .remove = __devexit_p(adcxx_remove),
 243 };
 244
 245 static int __init init_adcxx(void)
 246 {
 247         return spi_register_driver(&adcxx_driver);
 248 }
 249
 250 static void __exit exit_adcxx(void)
 251 {
 252         spi_unregister_driver(&adcxx_driver);
 253 }
 254
 255 module_init(init_adcxx);
 256 module_exit(exit_adcxx);
 257
 258 MODULE_AUTHOR("Marc Pignat");
 259 MODULE_DESCRIPTION("National Semiconductor adcxx8sxxx Linux driver");
 260 MODULE_LICENSE("GPL");