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];
  66         u8 rx_buf[2];
  67         int status;
  68         u32 value;
  69
  70         if (mutex_lock_interruptible(&adc->lock))
  71                 return -ERESTARTSYS;
  72
  73         if (adc->channels == 1) {
  74                 status = spi_read(spi, rx_buf, sizeof(rx_buf));
  75         } else {
  76                 tx_buf[0] = attr->index << 3; /* other bits are don't care */
  77                 status = spi_write_then_read(spi, tx_buf, sizeof(tx_buf),
  78                                                 rx_buf, sizeof(rx_buf));
  79         }
  80         if (status < 0) {
  81                 dev_warn(dev, "SPI synch. transfer failed with status %d\n",
  82                                 status);
  83                 goto out;
  84         }
  85
  86         value = (rx_buf[0] << 8) + rx_buf[1];
  87         dev_dbg(dev, "raw value = 0x%x\n", value);
  88
  89         value = value * adc->reference >> 12;
  90         status = sprintf(buf, "%d\n", value);
  91 out:
  92         mutex_unlock(&adc->lock);
  93         return status;
  94 }
  95
  96 static ssize_t adcxx_show_min(struct device *dev,
  97                 struct device_attribute *devattr, char *buf)
  98 {
  99         /* The minimum reference is 0 for this chip family */
 100         return sprintf(buf, "0\n");
 101 }
 102
 103 static ssize_t adcxx_show_max(struct device *dev,
 104                 struct device_attribute *devattr, char *buf)
 105 {
 106         struct spi_device *spi = to_spi_device(dev);
 107         struct adcxx *adc = dev_get_drvdata(&spi->dev);
 108         u32 reference;
 109
 110         if (mutex_lock_interruptible(&adc->lock))
 111                 return -ERESTARTSYS;
 112
 113         reference = adc->reference;
 114
 115         mutex_unlock(&adc->lock);
 116
 117         return sprintf(buf, "%d\n", reference);
 118 }
 119
 120 static ssize_t adcxx_set_max(struct device *dev,
 121         struct device_attribute *devattr, const char *buf, size_t count)
 122 {
 123         struct spi_device *spi = to_spi_device(dev);
 124         struct adcxx *adc = dev_get_drvdata(&spi->dev);
 125         unsigned long value;
 126
 127         if (strict_strtoul(buf, 10, &value))
 128                 return -EINVAL;
 129
 130         if (mutex_lock_interruptible(&adc->lock))
 131                 return -ERESTARTSYS;
 132
 133         adc->reference = value;
 134
 135         mutex_unlock(&adc->lock);
 136
 137         return count;
 138 }
 139
 140 static ssize_t adcxx_show_name(struct device *dev, struct device_attribute
 141                               *devattr, char *buf)
 142 {
 143         struct spi_device *spi = to_spi_device(dev);
 144         struct adcxx *adc = dev_get_drvdata(&spi->dev);
 145
 146         return sprintf(buf, "adcxx%ds\n", adc->channels);
 147 }
 148
 149 static struct sensor_device_attribute ad_input[] = {
 150         SENSOR_ATTR(name, S_IRUGO, adcxx_show_name, NULL, 0),
 151         SENSOR_ATTR(in_min, S_IRUGO, adcxx_show_min, NULL, 0),
 152         SENSOR_ATTR(in_max, S_IWUSR | S_IRUGO, adcxx_show_max,
 153                                         adcxx_set_max, 0),
 154         SENSOR_ATTR(in0_input, S_IRUGO, adcxx_read, NULL, 0),
 155         SENSOR_ATTR(in1_input, S_IRUGO, adcxx_read, NULL, 1),
 156         SENSOR_ATTR(in2_input, S_IRUGO, adcxx_read, NULL, 2),
 157         SENSOR_ATTR(in3_input, S_IRUGO, adcxx_read, NULL, 3),
 158         SENSOR_ATTR(in4_input, S_IRUGO, adcxx_read, NULL, 4),
 159         SENSOR_ATTR(in5_input, S_IRUGO, adcxx_read, NULL, 5),
 160         SENSOR_ATTR(in6_input, S_IRUGO, adcxx_read, NULL, 6),
 161         SENSOR_ATTR(in7_input, S_IRUGO, adcxx_read, NULL, 7),
 162 };
 163
 164 /*----------------------------------------------------------------------*/
 165
 166 static int __devinit adcxx_probe(struct spi_device *spi)
 167 {
 168         int channels = spi_get_device_id(spi)->driver_data;
 169         struct adcxx *adc;
 170         int status;
 171         int i;
 172
 173         adc = kzalloc(sizeof *adc, GFP_KERNEL);
 174         if (!adc)
 175                 return -ENOMEM;
 176
 177         /* set a default value for the reference */
 178         adc->reference = 3300;
 179         adc->channels = channels;
 180         mutex_init(&adc->lock);
 181
 182         mutex_lock(&adc->lock);
 183
 184         dev_set_drvdata(&spi->dev, adc);
 185
 186         for (i = 0; i < 3 + adc->channels; i++) {
 187                 status = device_create_file(&spi->dev, &ad_input[i].dev_attr);
 188                 if (status) {
 189                         dev_err(&spi->dev, "device_create_file failed.\n");
 190                         goto out_err;
 191                 }
 192         }
 193
 194         adc->hwmon_dev = hwmon_device_register(&spi->dev);
 195         if (IS_ERR(adc->hwmon_dev)) {
 196                 dev_err(&spi->dev, "hwmon_device_register failed.\n");
 197                 status = PTR_ERR(adc->hwmon_dev);
 198                 goto out_err;
 199         }
 200
 201         mutex_unlock(&adc->lock);
 202         return 0;
 203
 204 out_err:
 205         for (i--; i >= 0; i--)
 206                 device_remove_file(&spi->dev, &ad_input[i].dev_attr);
 207
 208         dev_set_drvdata(&spi->dev, NULL);
 209         mutex_unlock(&adc->lock);
 210         kfree(adc);
 211         return status;
 212 }
 213
 214 static int __devexit adcxx_remove(struct spi_device *spi)
 215 {
 216         struct adcxx *adc = dev_get_drvdata(&spi->dev);
 217         int i;
 218
 219         mutex_lock(&adc->lock);
 220         hwmon_device_unregister(adc->hwmon_dev);
 221         for (i = 0; i < 3 + adc->channels; i++)
 222                 device_remove_file(&spi->dev, &ad_input[i].dev_attr);
 223
 224         dev_set_drvdata(&spi->dev, NULL);
 225         mutex_unlock(&adc->lock);
 226         kfree(adc);
 227
 228         return 0;
 229 }
 230
 231 static const struct spi_device_id adcxx_ids[] = {
 232         { "adcxx1s", 1 },
 233         { "adcxx2s", 2 },
 234         { "adcxx4s", 4 },
 235         { "adcxx8s", 8 },
 236         { },
 237 };
 238 MODULE_DEVICE_TABLE(spi, adcxx_ids);
 239
 240 static struct spi_driver adcxx_driver = {
 241         .driver = {
 242                 .name   = "adcxx",
 243                 .owner  = THIS_MODULE,
 244         },
 245         .id_table = adcxx_ids,
 246         .probe  = adcxx_probe,
 247         .remove = __devexit_p(adcxx_remove),
 248 };
 249
 250 static int __init init_adcxx(void)
 251 {
 252         return spi_register_driver(&adcxx_driver);
 253 }
 254
 255 static void __exit exit_adcxx(void)
 256 {
 257         spi_unregister_driver(&adcxx_driver);
 258 }
 259
 260 module_init(init_adcxx);
 261 module_exit(exit_adcxx);
 262
 263 MODULE_AUTHOR("Marc Pignat");
 264 MODULE_DESCRIPTION("National Semiconductor adcxx8sxxx Linux driver");
 265 MODULE_LICENSE("GPL");