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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(spi, (const u8 *)&word, sizeof(word));
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(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
53static int max7301_probe(struct spi_device *spi)
54{
55 struct max7301 *ts;
56 int ret;
57
58 /* bits_per_word cannot be configured in platform data */
59 spi->bits_per_word = 16;
60 ret = spi_setup(spi);
61 if (ret < 0)
62 return ret;
63
64 ts = devm_kzalloc(&spi->dev, sizeof(struct max7301), GFP_KERNEL);
65 if (!ts)
66 return -ENOMEM;
67
68 ts->read = max7301_spi_read;
69 ts->write = max7301_spi_write;
70 ts->dev = &spi->dev;
71
72 ret = __max730x_probe(ts);
73 return ret;
74}
75
76static int max7301_remove(struct spi_device *spi)
77{
78 return __max730x_remove(&spi->dev);
79}
80
81static const struct spi_device_id max7301_id[] = {
82 { "max7301", 0 },
83 { }
84};
85MODULE_DEVICE_TABLE(spi, max7301_id);
86
87static struct spi_driver max7301_driver = {
88 .driver = {
89 .name = "max7301",
90 },
91 .probe = max7301_probe,
92 .remove = max7301_remove,
93 .id_table = max7301_id,
94};
95
96static int __init max7301_init(void)
97{
98 return spi_register_driver(&max7301_driver);
99}
100/* register after spi postcore initcall and before
101 * subsys initcalls that may rely on these GPIOs
102 */
103subsys_initcall(max7301_init);
104
105static void __exit max7301_exit(void)
106{
107 spi_unregister_driver(&max7301_driver);
108}
109module_exit(max7301_exit);
110
111MODULE_AUTHOR("Juergen Beisert, Wolfram Sang");
112MODULE_LICENSE("GPL v2");
113MODULE_DESCRIPTION("MAX7301 GPIO-Expander");
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (C) 2006 Juergen Beisert, Pengutronix
4 * Copyright (C) 2008 Guennadi Liakhovetski, Pengutronix
5 * Copyright (C) 2009 Wolfram Sang, Pengutronix
6 *
7 * Check max730x.c for further details.
8 */
9
10#include <linux/module.h>
11#include <linux/init.h>
12#include <linux/platform_device.h>
13#include <linux/mutex.h>
14#include <linux/slab.h>
15#include <linux/spi/spi.h>
16#include <linux/spi/max7301.h>
17
18/* A write to the MAX7301 means one message with one transfer */
19static int max7301_spi_write(struct device *dev, unsigned int reg,
20 unsigned int val)
21{
22 struct spi_device *spi = to_spi_device(dev);
23 u16 word = ((reg & 0x7F) << 8) | (val & 0xFF);
24
25 return spi_write_then_read(spi, &word, sizeof(word), NULL, 0);
26}
27
28/* A read from the MAX7301 means two transfers; here, one message each */
29
30static int max7301_spi_read(struct device *dev, unsigned int reg)
31{
32 int ret;
33 u16 word;
34 struct spi_device *spi = to_spi_device(dev);
35
36 word = 0x8000 | (reg << 8);
37 ret = spi_write_then_read(spi, &word, sizeof(word), &word,
38 sizeof(word));
39 if (ret)
40 return ret;
41 return word & 0xff;
42}
43
44static int max7301_probe(struct spi_device *spi)
45{
46 struct max7301 *ts;
47 int ret;
48
49 /* bits_per_word cannot be configured in platform data */
50 spi->bits_per_word = 16;
51 ret = spi_setup(spi);
52 if (ret < 0)
53 return ret;
54
55 ts = devm_kzalloc(&spi->dev, sizeof(struct max7301), GFP_KERNEL);
56 if (!ts)
57 return -ENOMEM;
58
59 ts->read = max7301_spi_read;
60 ts->write = max7301_spi_write;
61 ts->dev = &spi->dev;
62
63 ret = __max730x_probe(ts);
64 return ret;
65}
66
67static void max7301_remove(struct spi_device *spi)
68{
69 __max730x_remove(&spi->dev);
70}
71
72static const struct spi_device_id max7301_id[] = {
73 { "max7301", 0 },
74 { }
75};
76MODULE_DEVICE_TABLE(spi, max7301_id);
77
78static struct spi_driver max7301_driver = {
79 .driver = {
80 .name = "max7301",
81 },
82 .probe = max7301_probe,
83 .remove = max7301_remove,
84 .id_table = max7301_id,
85};
86
87static int __init max7301_init(void)
88{
89 return spi_register_driver(&max7301_driver);
90}
91/* register after spi postcore initcall and before
92 * subsys initcalls that may rely on these GPIOs
93 */
94subsys_initcall(max7301_init);
95
96static void __exit max7301_exit(void)
97{
98 spi_unregister_driver(&max7301_driver);
99}
100module_exit(max7301_exit);
101
102MODULE_AUTHOR("Juergen Beisert, Wolfram Sang");
103MODULE_LICENSE("GPL v2");
104MODULE_DESCRIPTION("MAX7301 GPIO-Expander");