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         int ret;
  37
  38         ret = kstrtoul(buf, 10, &val);
  39         if (ret)
  40                 return ret;
  41
  42         tmp[0] = val >> 8;
  43         tmp[1] = val & 0xff;
  44         spi_write(spi, tmp, sizeof(tmp));
  45         return count;
  46 }
  47
  48 static DEVICE_ATTR(value, S_IWUSR, NULL, dac7512_store_val);
  49
  50 static struct attribute *dac7512_attributes[] = {
  51         &dev_attr_value.attr,
  52         NULL
  53 };
  54
  55 static const struct attribute_group dac7512_attr_group = {
  56         .attrs = dac7512_attributes,
  57 };
  58
  59 static int dac7512_probe(struct spi_device *spi)
  60 {
  61         int ret;
  62
  63         spi->bits_per_word = 8;
  64         spi->mode = SPI_MODE_0;
  65         ret = spi_setup(spi);
  66         if (ret < 0)
  67                 return ret;
  68
  69         return sysfs_create_group(&spi->dev.kobj, &dac7512_attr_group);
  70 }
  71
  72 static int dac7512_remove(struct spi_device *spi)
  73 {
  74         sysfs_remove_group(&spi->dev.kobj, &dac7512_attr_group);
  75         return 0;
  76 }
  77
  78 static struct spi_driver dac7512_driver = {
  79         .driver = {
  80                 .name   = DAC7512_DRV_NAME,
  81                 .owner  = THIS_MODULE,
  82         },
  83         .probe  = dac7512_probe,
  84         .remove = dac7512_remove,
  85 };
  86
  87 module_spi_driver(dac7512_driver);
  88
  89 MODULE_AUTHOR("Daniel Mack <daniel@caiaq.de>");
  90 MODULE_DESCRIPTION("DAC7512 16-bit DAC");
  91 MODULE_LICENSE("GPL v2");
  92 MODULE_VERSION(DRIVER_VERSION);