1/*
2 * Copyright (C) 2006 Juergen Beisert, Pengutronix
3 * Copyright (C) 2008 Guennadi Liakhovetski, Pengutronix
4 * Copyright (C) 2009 Wolfram Sang, Pengutronix
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 *
10 * Check max730x.c for further details.
11 */
12
13#include <linux/module.h>
14#include <linux/init.h>
15#include <linux/platform_device.h>
16#include <linux/mutex.h>
17#include <linux/slab.h>
18#include <linux/spi/spi.h>
19#include <linux/spi/max7301.h>
20
21/* A write to the MAX7301 means one message with one transfer */
22static int max7301_spi_write(struct device *dev, unsigned int reg,
23 unsigned int val)
24{
25 struct spi_device *spi = to_spi_device(dev);
26 u16 word = ((reg & 0x7F) << 8) | (val & 0xFF);
27
28 return spi_write_then_read(spi, &word, sizeof(word), NULL, 0);
29}
30
31/* A read from the MAX7301 means two transfers; here, one message each */
32
33static int max7301_spi_read(struct device *dev, unsigned int reg)
34{
35 int ret;
36 u16 word;
37 struct spi_device *spi = to_spi_device(dev);
38
39 word = 0x8000 | (reg << 8);
40 ret = spi_write_then_read(spi, &word, sizeof(word), &word,
41 sizeof(word));
42 if (ret)
43 return ret;
44 return word & 0xff;
45}
46
47static int max7301_probe(struct spi_device *spi)
48{
49 struct max7301 *ts;
50 int ret;
51
52 /* bits_per_word cannot be configured in platform data */
53 spi->bits_per_word = 16;
54 ret = spi_setup(spi);
55 if (ret < 0)
56 return ret;
57
58 ts = devm_kzalloc(&spi->dev, sizeof(struct max7301), GFP_KERNEL);
59 if (!ts)
60 return -ENOMEM;
61
62 ts->read = max7301_spi_read;
63 ts->write = max7301_spi_write;
64 ts->dev = &spi->dev;
65
66 ret = __max730x_probe(ts);
67 return ret;
68}
69
70static int max7301_remove(struct spi_device *spi)
71{
72 return __max730x_remove(&spi->dev);
73}
74
75static const struct spi_device_id max7301_id[] = {
76 { "max7301", 0 },
77 { }
78};
79MODULE_DEVICE_TABLE(spi, max7301_id);
80
81static struct spi_driver max7301_driver = {
82 .driver = {
83 .name = "max7301",
84 },
85 .probe = max7301_probe,
86 .remove = max7301_remove,
87 .id_table = max7301_id,
88};
89
90static int __init max7301_init(void)
91{
92 return spi_register_driver(&max7301_driver);
93}
94/* register after spi postcore initcall and before
95 * subsys initcalls that may rely on these GPIOs
96 */
97subsys_initcall(max7301_init);
98
99static void __exit max7301_exit(void)
100{
101 spi_unregister_driver(&max7301_driver);
102}
103module_exit(max7301_exit);
104
105MODULE_AUTHOR("Juergen Beisert, Wolfram Sang");
106MODULE_LICENSE("GPL v2");
107MODULE_DESCRIPTION("MAX7301 GPIO-Expander");
108