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
 29static 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
 46static DEVICE_ATTR(value, S_IWUSR, NULL, dac7512_store_val);
 47
 48static struct attribute *dac7512_attributes[] = {
 49	&dev_attr_value.attr,
 50	NULL
 51};
 52
 53static const struct attribute_group dac7512_attr_group = {
 54	.attrs = dac7512_attributes,
 55};
 56
 57static 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
 70static int __devexit dac7512_remove(struct spi_device *spi)
 71{
 72	sysfs_remove_group(&spi->dev.kobj, &dac7512_attr_group);
 73	return 0;
 74}
 75
 76static 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
 85static int __init dac7512_init(void)
 86{
 87	return spi_register_driver(&dac7512_driver);
 88}
 89
 90static void __exit dac7512_exit(void)
 91{
 92	spi_unregister_driver(&dac7512_driver);
 93}
 94
 95MODULE_AUTHOR("Daniel Mack <daniel@caiaq.de>");
 96MODULE_DESCRIPTION("DAC7512 16-bit DAC");
 97MODULE_LICENSE("GPL v2");
 98MODULE_VERSION(DRIVER_VERSION);
 99
100module_init(dac7512_init);
101module_exit(dac7512_exit);