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Wolfram Sange9528052010-03-05 13:44:33 -08001/*
Juergen Beisert0c36ec32008-07-21 14:21:34 -07002 * Copyright (C) 2006 Juergen Beisert, Pengutronix
3 * Copyright (C) 2008 Guennadi Liakhovetski, Pengutronix
Wolfram Sange9528052010-03-05 13:44:33 -08004 * Copyright (C) 2009 Wolfram Sang, Pengutronix
Juergen Beisert0c36ec32008-07-21 14:21:34 -07005 *
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 *
Wolfram Sange9528052010-03-05 13:44:33 -080010 * Check max730x.c for further details.
Juergen Beisert0c36ec32008-07-21 14:21:34 -070011 */
12
Wolfram Sange9528052010-03-05 13:44:33 -080013#include <linux/module.h>
Juergen Beisert0c36ec32008-07-21 14:21:34 -070014#include <linux/init.h>
15#include <linux/platform_device.h>
16#include <linux/mutex.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090017#include <linux/slab.h>
Juergen Beisert0c36ec32008-07-21 14:21:34 -070018#include <linux/spi/spi.h>
19#include <linux/spi/max7301.h>
Juergen Beisert0c36ec32008-07-21 14:21:34 -070020
Wolfram Sange9528052010-03-05 13:44:33 -080021/* 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)
Juergen Beisert0c36ec32008-07-21 14:21:34 -070024{
Wolfram Sange9528052010-03-05 13:44:33 -080025 struct spi_device *spi = to_spi_device(dev);
Juergen Beisert0c36ec32008-07-21 14:21:34 -070026 u16 word = ((reg & 0x7F) << 8) | (val & 0xFF);
Wolfram Sange9528052010-03-05 13:44:33 -080027
Juergen Beisert0c36ec32008-07-21 14:21:34 -070028 return spi_write(spi, (const u8 *)&word, sizeof(word));
29}
30
Wolfram Sange9528052010-03-05 13:44:33 -080031/* A read from the MAX7301 means two transfers; here, one message each */
32
33static int max7301_spi_read(struct device *dev, unsigned int reg)
Juergen Beisert0c36ec32008-07-21 14:21:34 -070034{
35 int ret;
36 u16 word;
Wolfram Sange9528052010-03-05 13:44:33 -080037 struct spi_device *spi = to_spi_device(dev);
Juergen Beisert0c36ec32008-07-21 14:21:34 -070038
39 word = 0x8000 | (reg << 8);
40 ret = spi_write(spi, (const u8 *)&word, sizeof(word));
41 if (ret)
42 return ret;
43 /*
44 * This relies on the fact, that a transfer with NULL tx_buf shifts out
45 * zero bytes (=NOOP for MAX7301)
46 */
47 ret = spi_read(spi, (u8 *)&word, sizeof(word));
48 if (ret)
49 return ret;
50 return word & 0xff;
51}
52
Bill Pemberton38363092012-11-19 13:22:34 -050053static int max7301_probe(struct spi_device *spi)
Juergen Beisert0c36ec32008-07-21 14:21:34 -070054{
55 struct max7301 *ts;
Wolfram Sange9528052010-03-05 13:44:33 -080056 int ret;
Juergen Beisert0c36ec32008-07-21 14:21:34 -070057
Wolfram Sange9528052010-03-05 13:44:33 -080058 /* bits_per_word cannot be configured in platform data */
Christophe Leroy31eb4b552013-08-20 08:29:23 +020059 spi->bits_per_word = 16;
Juergen Beisert0c36ec32008-07-21 14:21:34 -070060 ret = spi_setup(spi);
61 if (ret < 0)
62 return ret;
63
Jingoo Han4cb06cd2013-03-15 18:15:06 +090064 ts = devm_kzalloc(&spi->dev, sizeof(struct max7301), GFP_KERNEL);
Juergen Beisert0c36ec32008-07-21 14:21:34 -070065 if (!ts)
66 return -ENOMEM;
67
Wolfram Sange9528052010-03-05 13:44:33 -080068 ts->read = max7301_spi_read;
69 ts->write = max7301_spi_write;
70 ts->dev = &spi->dev;
Juergen Beisert0c36ec32008-07-21 14:21:34 -070071
Wolfram Sange9528052010-03-05 13:44:33 -080072 ret = __max730x_probe(ts);
Juergen Beisert0c36ec32008-07-21 14:21:34 -070073 return ret;
74}
75
Bill Pemberton206210c2012-11-19 13:25:50 -050076static int max7301_remove(struct spi_device *spi)
Juergen Beisert0c36ec32008-07-21 14:21:34 -070077{
Wolfram Sange9528052010-03-05 13:44:33 -080078 return __max730x_remove(&spi->dev);
Juergen Beisert0c36ec32008-07-21 14:21:34 -070079}
80
Wolfram Sange9528052010-03-05 13:44:33 -080081static const struct spi_device_id max7301_id[] = {
82 { "max7301", 0 },
83 { }
84};
85MODULE_DEVICE_TABLE(spi, max7301_id);
86
Juergen Beisert0c36ec32008-07-21 14:21:34 -070087static struct spi_driver max7301_driver = {
88 .driver = {
Wolfram Sange9528052010-03-05 13:44:33 -080089 .name = "max7301",
90 .owner = THIS_MODULE,
Juergen Beisert0c36ec32008-07-21 14:21:34 -070091 },
Wolfram Sange9528052010-03-05 13:44:33 -080092 .probe = max7301_probe,
Bill Pemberton8283c4f2012-11-19 13:20:08 -050093 .remove = max7301_remove,
Wolfram Sange9528052010-03-05 13:44:33 -080094 .id_table = max7301_id,
Juergen Beisert0c36ec32008-07-21 14:21:34 -070095};
96
97static int __init max7301_init(void)
98{
99 return spi_register_driver(&max7301_driver);
100}
David Brownell673c0c02008-10-15 22:02:46 -0700101/* register after spi postcore initcall and before
102 * subsys initcalls that may rely on these GPIOs
103 */
104subsys_initcall(max7301_init);
Juergen Beisert0c36ec32008-07-21 14:21:34 -0700105
106static void __exit max7301_exit(void)
107{
108 spi_unregister_driver(&max7301_driver);
109}
Juergen Beisert0c36ec32008-07-21 14:21:34 -0700110module_exit(max7301_exit);
111
Wolfram Sange9528052010-03-05 13:44:33 -0800112MODULE_AUTHOR("Juergen Beisert, Wolfram Sang");
Juergen Beisert0c36ec32008-07-21 14:21:34 -0700113MODULE_LICENSE("GPL v2");
Wolfram Sange9528052010-03-05 13:44:33 -0800114MODULE_DESCRIPTION("MAX7301 GPIO-Expander");