1d2912cb1SThomas Gleixner // SPDX-License-Identifier: GPL-2.0-only
2c103de24SGrant Likely /*
3c103de24SGrant Likely * Copyright (C) 2006 Juergen Beisert, Pengutronix
4c103de24SGrant Likely * Copyright (C) 2008 Guennadi Liakhovetski, Pengutronix
5c103de24SGrant Likely * Copyright (C) 2009 Wolfram Sang, Pengutronix
6c103de24SGrant Likely *
7c103de24SGrant Likely * Check max730x.c for further details.
8c103de24SGrant Likely */
9c103de24SGrant Likely
10c103de24SGrant Likely #include <linux/module.h>
11c103de24SGrant Likely #include <linux/init.h>
12c103de24SGrant Likely #include <linux/platform_device.h>
13c103de24SGrant Likely #include <linux/mutex.h>
14c103de24SGrant Likely #include <linux/slab.h>
15c103de24SGrant Likely #include <linux/spi/spi.h>
16c103de24SGrant Likely #include <linux/spi/max7301.h>
17c103de24SGrant Likely
18c103de24SGrant Likely /* A write to the MAX7301 means one message with one transfer */
max7301_spi_write(struct device * dev,unsigned int reg,unsigned int val)19c103de24SGrant Likely static int max7301_spi_write(struct device *dev, unsigned int reg,
20c103de24SGrant Likely unsigned int val)
21c103de24SGrant Likely {
22c103de24SGrant Likely struct spi_device *spi = to_spi_device(dev);
23c103de24SGrant Likely u16 word = ((reg & 0x7F) << 8) | (val & 0xFF);
24c103de24SGrant Likely
25abf221d2SChristophe Leroy return spi_write_then_read(spi, &word, sizeof(word), NULL, 0);
26c103de24SGrant Likely }
27c103de24SGrant Likely
28c103de24SGrant Likely /* A read from the MAX7301 means two transfers; here, one message each */
29c103de24SGrant Likely
max7301_spi_read(struct device * dev,unsigned int reg)30c103de24SGrant Likely static int max7301_spi_read(struct device *dev, unsigned int reg)
31c103de24SGrant Likely {
32c103de24SGrant Likely int ret;
33c103de24SGrant Likely u16 word;
34c103de24SGrant Likely struct spi_device *spi = to_spi_device(dev);
35c103de24SGrant Likely
36c103de24SGrant Likely word = 0x8000 | (reg << 8);
37abf221d2SChristophe Leroy ret = spi_write_then_read(spi, &word, sizeof(word), &word,
38abf221d2SChristophe Leroy sizeof(word));
39c103de24SGrant Likely if (ret)
40c103de24SGrant Likely return ret;
41c103de24SGrant Likely return word & 0xff;
42c103de24SGrant Likely }
43c103de24SGrant Likely
max7301_probe(struct spi_device * spi)443836309dSBill Pemberton static int max7301_probe(struct spi_device *spi)
45c103de24SGrant Likely {
46c103de24SGrant Likely struct max7301 *ts;
47c103de24SGrant Likely int ret;
48c103de24SGrant Likely
49c103de24SGrant Likely /* bits_per_word cannot be configured in platform data */
50c103de24SGrant Likely spi->bits_per_word = 16;
51c103de24SGrant Likely ret = spi_setup(spi);
52c103de24SGrant Likely if (ret < 0)
53c103de24SGrant Likely return ret;
54c103de24SGrant Likely
554cb06cd5SJingoo Han ts = devm_kzalloc(&spi->dev, sizeof(struct max7301), GFP_KERNEL);
56c103de24SGrant Likely if (!ts)
57c103de24SGrant Likely return -ENOMEM;
58c103de24SGrant Likely
59c103de24SGrant Likely ts->read = max7301_spi_read;
60c103de24SGrant Likely ts->write = max7301_spi_write;
61c103de24SGrant Likely ts->dev = &spi->dev;
62c103de24SGrant Likely
63c103de24SGrant Likely ret = __max730x_probe(ts);
64c103de24SGrant Likely return ret;
65c103de24SGrant Likely }
66c103de24SGrant Likely
max7301_remove(struct spi_device * spi)67*a0386bbaSUwe Kleine-König static void max7301_remove(struct spi_device *spi)
68c103de24SGrant Likely {
6906de2cd7SUwe Kleine-König __max730x_remove(&spi->dev);
70c103de24SGrant Likely }
71c103de24SGrant Likely
72c103de24SGrant Likely static const struct spi_device_id max7301_id[] = {
73c103de24SGrant Likely { "max7301", 0 },
74c103de24SGrant Likely { }
75c103de24SGrant Likely };
76c103de24SGrant Likely MODULE_DEVICE_TABLE(spi, max7301_id);
77c103de24SGrant Likely
78c103de24SGrant Likely static struct spi_driver max7301_driver = {
79c103de24SGrant Likely .driver = {
80c103de24SGrant Likely .name = "max7301",
81c103de24SGrant Likely },
82c103de24SGrant Likely .probe = max7301_probe,
838283c4ffSBill Pemberton .remove = max7301_remove,
84c103de24SGrant Likely .id_table = max7301_id,
85c103de24SGrant Likely };
86c103de24SGrant Likely
max7301_init(void)87c103de24SGrant Likely static int __init max7301_init(void)
88c103de24SGrant Likely {
89c103de24SGrant Likely return spi_register_driver(&max7301_driver);
90c103de24SGrant Likely }
91c103de24SGrant Likely /* register after spi postcore initcall and before
92c103de24SGrant Likely * subsys initcalls that may rely on these GPIOs
93c103de24SGrant Likely */
94c103de24SGrant Likely subsys_initcall(max7301_init);
95c103de24SGrant Likely
max7301_exit(void)96c103de24SGrant Likely static void __exit max7301_exit(void)
97c103de24SGrant Likely {
98c103de24SGrant Likely spi_unregister_driver(&max7301_driver);
99c103de24SGrant Likely }
100c103de24SGrant Likely module_exit(max7301_exit);
101c103de24SGrant Likely
102c103de24SGrant Likely MODULE_AUTHOR("Juergen Beisert, Wolfram Sang");
103c103de24SGrant Likely MODULE_LICENSE("GPL v2");
104c103de24SGrant Likely MODULE_DESCRIPTION("MAX7301 GPIO-Expander");
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