]>
Commit | Line | Data |
---|---|---|
e952805d | 1 | /* |
0c36ec31 JB |
2 | * drivers/gpio/max7301.c |
3 | * | |
4 | * Copyright (C) 2006 Juergen Beisert, Pengutronix | |
5 | * Copyright (C) 2008 Guennadi Liakhovetski, Pengutronix | |
e952805d | 6 | * Copyright (C) 2009 Wolfram Sang, Pengutronix |
0c36ec31 JB |
7 | * |
8 | * This program is free software; you can redistribute it and/or modify | |
9 | * it under the terms of the GNU General Public License version 2 as | |
10 | * published by the Free Software Foundation. | |
11 | * | |
e952805d | 12 | * Check max730x.c for further details. |
0c36ec31 JB |
13 | */ |
14 | ||
e952805d | 15 | #include <linux/module.h> |
0c36ec31 JB |
16 | #include <linux/init.h> |
17 | #include <linux/platform_device.h> | |
18 | #include <linux/mutex.h> | |
5a0e3ad6 | 19 | #include <linux/slab.h> |
0c36ec31 JB |
20 | #include <linux/spi/spi.h> |
21 | #include <linux/spi/max7301.h> | |
0c36ec31 | 22 | |
e952805d WS |
23 | /* A write to the MAX7301 means one message with one transfer */ |
24 | static int max7301_spi_write(struct device *dev, unsigned int reg, | |
25 | unsigned int val) | |
0c36ec31 | 26 | { |
e952805d | 27 | struct spi_device *spi = to_spi_device(dev); |
0c36ec31 | 28 | u16 word = ((reg & 0x7F) << 8) | (val & 0xFF); |
e952805d | 29 | |
0c36ec31 JB |
30 | return spi_write(spi, (const u8 *)&word, sizeof(word)); |
31 | } | |
32 | ||
e952805d WS |
33 | /* A read from the MAX7301 means two transfers; here, one message each */ |
34 | ||
35 | static int max7301_spi_read(struct device *dev, unsigned int reg) | |
0c36ec31 JB |
36 | { |
37 | int ret; | |
38 | u16 word; | |
e952805d | 39 | struct spi_device *spi = to_spi_device(dev); |
0c36ec31 JB |
40 | |
41 | word = 0x8000 | (reg << 8); | |
42 | ret = spi_write(spi, (const u8 *)&word, sizeof(word)); | |
43 | if (ret) | |
44 | return ret; | |
45 | /* | |
46 | * This relies on the fact, that a transfer with NULL tx_buf shifts out | |
47 | * zero bytes (=NOOP for MAX7301) | |
48 | */ | |
49 | ret = spi_read(spi, (u8 *)&word, sizeof(word)); | |
50 | if (ret) | |
51 | return ret; | |
52 | return word & 0xff; | |
53 | } | |
54 | ||
0c36ec31 JB |
55 | static int __devinit max7301_probe(struct spi_device *spi) |
56 | { | |
57 | struct max7301 *ts; | |
e952805d | 58 | int ret; |
0c36ec31 | 59 | |
e952805d | 60 | /* bits_per_word cannot be configured in platform data */ |
0c36ec31 | 61 | spi->bits_per_word = 16; |
0c36ec31 JB |
62 | ret = spi_setup(spi); |
63 | if (ret < 0) | |
64 | return ret; | |
65 | ||
66 | ts = kzalloc(sizeof(struct max7301), GFP_KERNEL); | |
67 | if (!ts) | |
68 | return -ENOMEM; | |
69 | ||
e952805d WS |
70 | ts->read = max7301_spi_read; |
71 | ts->write = max7301_spi_write; | |
72 | ts->dev = &spi->dev; | |
0c36ec31 | 73 | |
e952805d | 74 | ret = __max730x_probe(ts); |
c557fa3e | 75 | if (ret) |
e952805d | 76 | kfree(ts); |
0c36ec31 JB |
77 | return ret; |
78 | } | |
79 | ||
de3483b0 | 80 | static int __devexit max7301_remove(struct spi_device *spi) |
0c36ec31 | 81 | { |
e952805d | 82 | return __max730x_remove(&spi->dev); |
0c36ec31 JB |
83 | } |
84 | ||
e952805d WS |
85 | static const struct spi_device_id max7301_id[] = { |
86 | { "max7301", 0 }, | |
87 | { } | |
88 | }; | |
89 | MODULE_DEVICE_TABLE(spi, max7301_id); | |
90 | ||
0c36ec31 JB |
91 | static struct spi_driver max7301_driver = { |
92 | .driver = { | |
e952805d WS |
93 | .name = "max7301", |
94 | .owner = THIS_MODULE, | |
0c36ec31 | 95 | }, |
e952805d WS |
96 | .probe = max7301_probe, |
97 | .remove = __devexit_p(max7301_remove), | |
98 | .id_table = max7301_id, | |
0c36ec31 JB |
99 | }; |
100 | ||
101 | static int __init max7301_init(void) | |
102 | { | |
103 | return spi_register_driver(&max7301_driver); | |
104 | } | |
673c0c00 DB |
105 | /* register after spi postcore initcall and before |
106 | * subsys initcalls that may rely on these GPIOs | |
107 | */ | |
108 | subsys_initcall(max7301_init); | |
0c36ec31 JB |
109 | |
110 | static void __exit max7301_exit(void) | |
111 | { | |
112 | spi_unregister_driver(&max7301_driver); | |
113 | } | |
0c36ec31 JB |
114 | module_exit(max7301_exit); |
115 | ||
e952805d | 116 | MODULE_AUTHOR("Juergen Beisert, Wolfram Sang"); |
0c36ec31 | 117 | MODULE_LICENSE("GPL v2"); |
e952805d | 118 | MODULE_DESCRIPTION("MAX7301 GPIO-Expander"); |