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
dac7512_store_val(struct device * dev,struct device_attribute * attr,const char * buf,size_t count)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
dac7512_probe(struct spi_device * spi)57 static int 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
dac7512_remove(struct spi_device * spi)70 static int 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 = dac7512_remove,
83 };
84
85 module_spi_driver(dac7512_driver);
86
87 MODULE_AUTHOR("Daniel Mack <daniel@caiaq.de>");
88 MODULE_DESCRIPTION("DAC7512 16-bit DAC");
89 MODULE_LICENSE("GPL v2");
90 MODULE_VERSION(DRIVER_VERSION);
91