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
dac7512_store_val(struct device * dev,struct device_attribute * attr,const char * buf,size_t count)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
dac7512_probe(struct spi_device * spi)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
dac7512_remove(struct spi_device * spi)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");
104