Commit | Line | Data |
---|---|---|
e952805d | 1 | /* |
0c36ec31 JB |
2 | * Copyright (C) 2006 Juergen Beisert, Pengutronix |
3 | * Copyright (C) 2008 Guennadi Liakhovetski, Pengutronix | |
e952805d | 4 | * Copyright (C) 2009 Wolfram Sang, Pengutronix |
0c36ec31 JB |
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 | * | |
e952805d | 10 | * Check max730x.c for further details. |
0c36ec31 JB |
11 | */ |
12 | ||
e952805d | 13 | #include <linux/module.h> |
0c36ec31 JB |
14 | #include <linux/init.h> |
15 | #include <linux/platform_device.h> | |
16 | #include <linux/mutex.h> | |
5a0e3ad6 | 17 | #include <linux/slab.h> |
0c36ec31 JB |
18 | #include <linux/spi/spi.h> |
19 | #include <linux/spi/max7301.h> | |
0c36ec31 | 20 | |
e952805d WS |
21 | /* A write to the MAX7301 means one message with one transfer */ |
22 | static int max7301_spi_write(struct device *dev, unsigned int reg, | |
23 | unsigned int val) | |
0c36ec31 | 24 | { |
e952805d | 25 | struct spi_device *spi = to_spi_device(dev); |
0c36ec31 | 26 | u16 word = ((reg & 0x7F) << 8) | (val & 0xFF); |
e952805d | 27 | |
0c36ec31 JB |
28 | return spi_write(spi, (const u8 *)&word, sizeof(word)); |
29 | } | |
30 | ||
e952805d WS |
31 | /* A read from the MAX7301 means two transfers; here, one message each */ |
32 | ||
33 | static int max7301_spi_read(struct device *dev, unsigned int reg) | |
0c36ec31 JB |
34 | { |
35 | int ret; | |
36 | u16 word; | |
e952805d | 37 | struct spi_device *spi = to_spi_device(dev); |
0c36ec31 JB |
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 | ||
3836309d | 53 | static int max7301_probe(struct spi_device *spi) |
0c36ec31 JB |
54 | { |
55 | struct max7301 *ts; | |
e952805d | 56 | int ret; |
0c36ec31 | 57 | |
e952805d | 58 | /* bits_per_word cannot be configured in platform data */ |
31eb4b55 | 59 | spi->bits_per_word = 16; |
0c36ec31 JB |
60 | ret = spi_setup(spi); |
61 | if (ret < 0) | |
62 | return ret; | |
63 | ||
4cb06cd5 | 64 | ts = devm_kzalloc(&spi->dev, sizeof(struct max7301), GFP_KERNEL); |
0c36ec31 JB |
65 | if (!ts) |
66 | return -ENOMEM; | |
67 | ||
e952805d WS |
68 | ts->read = max7301_spi_read; |
69 | ts->write = max7301_spi_write; | |
70 | ts->dev = &spi->dev; | |
0c36ec31 | 71 | |
e952805d | 72 | ret = __max730x_probe(ts); |
0c36ec31 JB |
73 | return ret; |
74 | } | |
75 | ||
206210ce | 76 | static int max7301_remove(struct spi_device *spi) |
0c36ec31 | 77 | { |
e952805d | 78 | return __max730x_remove(&spi->dev); |
0c36ec31 JB |
79 | } |
80 | ||
e952805d WS |
81 | static const struct spi_device_id max7301_id[] = { |
82 | { "max7301", 0 }, | |
83 | { } | |
84 | }; | |
85 | MODULE_DEVICE_TABLE(spi, max7301_id); | |
86 | ||
0c36ec31 JB |
87 | static struct spi_driver max7301_driver = { |
88 | .driver = { | |
e952805d WS |
89 | .name = "max7301", |
90 | .owner = THIS_MODULE, | |
0c36ec31 | 91 | }, |
e952805d | 92 | .probe = max7301_probe, |
8283c4ff | 93 | .remove = max7301_remove, |
e952805d | 94 | .id_table = max7301_id, |
0c36ec31 JB |
95 | }; |
96 | ||
97 | static int __init max7301_init(void) | |
98 | { | |
99 | return spi_register_driver(&max7301_driver); | |
100 | } | |
673c0c00 DB |
101 | /* register after spi postcore initcall and before |
102 | * subsys initcalls that may rely on these GPIOs | |
103 | */ | |
104 | subsys_initcall(max7301_init); | |
0c36ec31 JB |
105 | |
106 | static void __exit max7301_exit(void) | |
107 | { | |
108 | spi_unregister_driver(&max7301_driver); | |
109 | } | |
0c36ec31 JB |
110 | module_exit(max7301_exit); |
111 | ||
e952805d | 112 | MODULE_AUTHOR("Juergen Beisert, Wolfram Sang"); |
0c36ec31 | 113 | MODULE_LICENSE("GPL v2"); |
e952805d | 114 | MODULE_DESCRIPTION("MAX7301 GPIO-Expander"); |