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/spi/spi.h>
  24 #include <linux/of.h>
  25
  26 static ssize_t dac7512_store_val(struct device *dev,
  27                                  struct device_attribute *attr,
  28                                  const char *buf, size_t count)
  29 {
  30         struct spi_device *spi = to_spi_device(dev);
  31         unsigned char tmp[2];
  32         unsigned long val;
  33         int ret;
  34
  35         ret = kstrtoul(buf, 10, &val);
  36         if (ret)
  37                 return ret;
  38
  39         tmp[0] = val >> 8;
  40         tmp[1] = val & 0xff;
  41         spi_write(spi, tmp, sizeof(tmp));
  42         return count;
  43 }
  44
  45 static DEVICE_ATTR(value, S_IWUSR, NULL, dac7512_store_val);
  46
  47 static struct attribute *dac7512_attributes[] = {
  48         &dev_attr_value.attr,
  49         NULL
  50 };
  51
  52 static const struct attribute_group dac7512_attr_group = {
  53         .attrs = dac7512_attributes,
  54 };
  55
  56 static int dac7512_probe(struct spi_device *spi)
  57 {
  58         int ret;
  59
  60         spi->bits_per_word = 8;
  61         spi->mode = SPI_MODE_0;
  62         ret = spi_setup(spi);
  63         if (ret < 0)
  64                 return ret;
  65
  66         return sysfs_create_group(&spi->dev.kobj, &dac7512_attr_group);
  67 }
  68
  69 static int dac7512_remove(struct spi_device *spi)
  70 {
  71         sysfs_remove_group(&spi->dev.kobj, &dac7512_attr_group);
  72         return 0;
  73 }
  74
  75 static const struct spi_device_id dac7512_id_table[] = {
  76         { "dac7512", 0 },
  77         { }
  78 };
  79 MODULE_DEVICE_TABLE(spi, dac7512_id_table);
  80
  81 #ifdef CONFIG_OF
  82 static const struct of_device_id dac7512_of_match[] = {
  83         { .compatible = "ti,dac7512", },
  84         { }
  85 };
  86 MODULE_DEVICE_TABLE(of, dac7512_of_match);
  87 #endif
  88
  89 static struct spi_driver dac7512_driver = {
  90         .driver = {
  91                 .name   = "dac7512",
  92                 .of_match_table = of_match_ptr(dac7512_of_match),
  93         },
  94         .probe  = dac7512_probe,
  95         .remove = dac7512_remove,
  96         .id_table = dac7512_id_table,
  97 };
  98
  99 module_spi_driver(dac7512_driver);
 100
 101 MODULE_AUTHOR("Daniel Mack <daniel@caiaq.de>");
 102 MODULE_DESCRIPTION("DAC7512 16-bit DAC");
 103 MODULE_LICENSE("GPL v2");