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