drivers/misc/ti_dac7512.c

   1 /*
   2  *  dac7512.c - Linux kernel module for
   3  *      Texas Instruments DAC7512
   4  *
   5  *  Copyright (c) 2009 Daniel Mack <daniel@caiaq.de>
   6  *
   7  *  This program is free software; you can redistribute it and/or modify
   8  *  it under the terms of the GNU General Public License as published by
   9  *  the Free Software Foundation; either version 2 of the License, or
  10  *  (at your option) any later version.
  11  *
  12  *  This program is distributed in the hope that it will be useful,
  13  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  *  GNU General Public License for more details.
  16  *
  17  *  You should have received a copy of the GNU General Public License
  18  *  along with this program; if not, write to the Free Software
  19  *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  20  */
  21
  22 #include <linux/module.h>
  23 #include <linux/init.h>
  24 #include <linux/spi/spi.h>
  25
  26 #define DAC7512_DRV_NAME        "dac7512"
  27 #define DRIVER_VERSION          "1.0"
  28
  29 static ssize_t dac7512_store_val(struct device *dev,
  30                                  struct device_attribute *attr,
  31                                  const char *buf, size_t count)
  32 {
  33         struct spi_device *spi = to_spi_device(dev);
  34         unsigned char tmp[2];
  35         unsigned long val;
  36
  37         if (strict_strtoul(buf, 10, &val) < 0)
  38                 return -EINVAL;
  39
  40         tmp[0] = val >> 8;
  41         tmp[1] = val & 0xff;
  42         spi_write(spi, tmp, sizeof(tmp));
  43         return count;
  44 }
  45
  46 static DEVICE_ATTR(value, S_IWUSR, NULL, dac7512_store_val);
  47
  48 static struct attribute *dac7512_attributes[] = {
  49         &dev_attr_value.attr,
  50         NULL
  51 };
  52
  53 static const struct attribute_group dac7512_attr_group = {
  54         .attrs = dac7512_attributes,
  55 };
  56
  57 static int __devinit dac7512_probe(struct spi_device *spi)
  58 {
  59         int ret;
  60
  61         spi->bits_per_word = 8;
  62         spi->mode = SPI_MODE_0;
  63         ret = spi_setup(spi);
  64         if (ret < 0)
  65                 return ret;
  66
  67         return sysfs_create_group(&spi->dev.kobj, &dac7512_attr_group);
  68 }
  69
  70 static int __devexit dac7512_remove(struct spi_device *spi)
  71 {
  72         sysfs_remove_group(&spi->dev.kobj, &dac7512_attr_group);
  73         return 0;
  74 }
  75
  76 static struct spi_driver dac7512_driver = {
  77         .driver = {
  78                 .name   = DAC7512_DRV_NAME,
  79                 .owner  = THIS_MODULE,
  80         },
  81         .probe  = dac7512_probe,
  82         .remove = __devexit_p(dac7512_remove),
  83 };
  84
  85 static int __init dac7512_init(void)
  86 {
  87         return spi_register_driver(&dac7512_driver);
  88 }
  89
  90 static void __exit dac7512_exit(void)
  91 {
  92         spi_unregister_driver(&dac7512_driver);
  93 }
  94
  95 MODULE_AUTHOR("Daniel Mack <daniel@caiaq.de>");
  96 MODULE_DESCRIPTION("DAC7512 16-bit DAC");
  97 MODULE_LICENSE("GPL v2");
  98 MODULE_VERSION(DRIVER_VERSION);
  99
 100 module_init(dac7512_init);
 101 module_exit(dac7512_exit);