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d2912cb1 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
e952805d | 2 | /* |
0c36ec31 JB |
3 | * Copyright (C) 2006 Juergen Beisert, Pengutronix |
4 | * Copyright (C) 2008 Guennadi Liakhovetski, Pengutronix | |
e952805d | 5 | * Copyright (C) 2009 Wolfram Sang, Pengutronix |
0c36ec31 | 6 | * |
e952805d | 7 | * Check max730x.c for further details. |
0c36ec31 JB |
8 | */ |
9 | ||
e952805d | 10 | #include <linux/module.h> |
0c36ec31 JB |
11 | #include <linux/init.h> |
12 | #include <linux/platform_device.h> | |
13 | #include <linux/mutex.h> | |
5a0e3ad6 | 14 | #include <linux/slab.h> |
0c36ec31 JB |
15 | #include <linux/spi/spi.h> |
16 | #include <linux/spi/max7301.h> | |
0c36ec31 | 17 | |
e952805d WS |
18 | /* A write to the MAX7301 means one message with one transfer */ |
19 | static int max7301_spi_write(struct device *dev, unsigned int reg, | |
20 | unsigned int val) | |
0c36ec31 | 21 | { |
e952805d | 22 | struct spi_device *spi = to_spi_device(dev); |
0c36ec31 | 23 | u16 word = ((reg & 0x7F) << 8) | (val & 0xFF); |
e952805d | 24 | |
abf221d2 | 25 | return spi_write_then_read(spi, &word, sizeof(word), NULL, 0); |
0c36ec31 JB |
26 | } |
27 | ||
e952805d WS |
28 | /* A read from the MAX7301 means two transfers; here, one message each */ |
29 | ||
30 | static int max7301_spi_read(struct device *dev, unsigned int reg) | |
0c36ec31 JB |
31 | { |
32 | int ret; | |
33 | u16 word; | |
e952805d | 34 | struct spi_device *spi = to_spi_device(dev); |
0c36ec31 JB |
35 | |
36 | word = 0x8000 | (reg << 8); | |
abf221d2 CL |
37 | ret = spi_write_then_read(spi, &word, sizeof(word), &word, |
38 | sizeof(word)); | |
0c36ec31 JB |
39 | if (ret) |
40 | return ret; | |
41 | return word & 0xff; | |
42 | } | |
43 | ||
3836309d | 44 | static int max7301_probe(struct spi_device *spi) |
0c36ec31 JB |
45 | { |
46 | struct max7301 *ts; | |
e952805d | 47 | int ret; |
0c36ec31 | 48 | |
e952805d | 49 | /* bits_per_word cannot be configured in platform data */ |
31eb4b55 | 50 | spi->bits_per_word = 16; |
0c36ec31 JB |
51 | ret = spi_setup(spi); |
52 | if (ret < 0) | |
53 | return ret; | |
54 | ||
4cb06cd5 | 55 | ts = devm_kzalloc(&spi->dev, sizeof(struct max7301), GFP_KERNEL); |
0c36ec31 JB |
56 | if (!ts) |
57 | return -ENOMEM; | |
58 | ||
e952805d WS |
59 | ts->read = max7301_spi_read; |
60 | ts->write = max7301_spi_write; | |
61 | ts->dev = &spi->dev; | |
0c36ec31 | 62 | |
e952805d | 63 | ret = __max730x_probe(ts); |
0c36ec31 JB |
64 | return ret; |
65 | } | |
66 | ||
206210ce | 67 | static int max7301_remove(struct spi_device *spi) |
0c36ec31 | 68 | { |
e952805d | 69 | return __max730x_remove(&spi->dev); |
0c36ec31 JB |
70 | } |
71 | ||
e952805d WS |
72 | static const struct spi_device_id max7301_id[] = { |
73 | { "max7301", 0 }, | |
74 | { } | |
75 | }; | |
76 | MODULE_DEVICE_TABLE(spi, max7301_id); | |
77 | ||
0c36ec31 JB |
78 | static struct spi_driver max7301_driver = { |
79 | .driver = { | |
e952805d | 80 | .name = "max7301", |
0c36ec31 | 81 | }, |
e952805d | 82 | .probe = max7301_probe, |
8283c4ff | 83 | .remove = max7301_remove, |
e952805d | 84 | .id_table = max7301_id, |
0c36ec31 JB |
85 | }; |
86 | ||
87 | static int __init max7301_init(void) | |
88 | { | |
89 | return spi_register_driver(&max7301_driver); | |
90 | } | |
673c0c00 DB |
91 | /* register after spi postcore initcall and before |
92 | * subsys initcalls that may rely on these GPIOs | |
93 | */ | |
94 | subsys_initcall(max7301_init); | |
0c36ec31 JB |
95 | |
96 | static void __exit max7301_exit(void) | |
97 | { | |
98 | spi_unregister_driver(&max7301_driver); | |
99 | } | |
0c36ec31 JB |
100 | module_exit(max7301_exit); |
101 | ||
e952805d | 102 | MODULE_AUTHOR("Juergen Beisert, Wolfram Sang"); |
0c36ec31 | 103 | MODULE_LICENSE("GPL v2"); |
e952805d | 104 | MODULE_DESCRIPTION("MAX7301 GPIO-Expander"); |