1*4882a593Smuzhiyun // SPDX-License-Identifier: GPL-2.0-only
2*4882a593Smuzhiyun /*
3*4882a593Smuzhiyun * Copyright (C) 2006 Juergen Beisert, Pengutronix
4*4882a593Smuzhiyun * Copyright (C) 2008 Guennadi Liakhovetski, Pengutronix
5*4882a593Smuzhiyun * Copyright (C) 2009 Wolfram Sang, Pengutronix
6*4882a593Smuzhiyun *
7*4882a593Smuzhiyun * Check max730x.c for further details.
8*4882a593Smuzhiyun */
9*4882a593Smuzhiyun
10*4882a593Smuzhiyun #include <linux/module.h>
11*4882a593Smuzhiyun #include <linux/init.h>
12*4882a593Smuzhiyun #include <linux/platform_device.h>
13*4882a593Smuzhiyun #include <linux/mutex.h>
14*4882a593Smuzhiyun #include <linux/slab.h>
15*4882a593Smuzhiyun #include <linux/spi/spi.h>
16*4882a593Smuzhiyun #include <linux/spi/max7301.h>
17*4882a593Smuzhiyun
18*4882a593Smuzhiyun /* A write to the MAX7301 means one message with one transfer */
max7301_spi_write(struct device * dev,unsigned int reg,unsigned int val)19*4882a593Smuzhiyun static int max7301_spi_write(struct device *dev, unsigned int reg,
20*4882a593Smuzhiyun unsigned int val)
21*4882a593Smuzhiyun {
22*4882a593Smuzhiyun struct spi_device *spi = to_spi_device(dev);
23*4882a593Smuzhiyun u16 word = ((reg & 0x7F) << 8) | (val & 0xFF);
24*4882a593Smuzhiyun
25*4882a593Smuzhiyun return spi_write_then_read(spi, &word, sizeof(word), NULL, 0);
26*4882a593Smuzhiyun }
27*4882a593Smuzhiyun
28*4882a593Smuzhiyun /* A read from the MAX7301 means two transfers; here, one message each */
29*4882a593Smuzhiyun
max7301_spi_read(struct device * dev,unsigned int reg)30*4882a593Smuzhiyun static int max7301_spi_read(struct device *dev, unsigned int reg)
31*4882a593Smuzhiyun {
32*4882a593Smuzhiyun int ret;
33*4882a593Smuzhiyun u16 word;
34*4882a593Smuzhiyun struct spi_device *spi = to_spi_device(dev);
35*4882a593Smuzhiyun
36*4882a593Smuzhiyun word = 0x8000 | (reg << 8);
37*4882a593Smuzhiyun ret = spi_write_then_read(spi, &word, sizeof(word), &word,
38*4882a593Smuzhiyun sizeof(word));
39*4882a593Smuzhiyun if (ret)
40*4882a593Smuzhiyun return ret;
41*4882a593Smuzhiyun return word & 0xff;
42*4882a593Smuzhiyun }
43*4882a593Smuzhiyun
max7301_probe(struct spi_device * spi)44*4882a593Smuzhiyun static int max7301_probe(struct spi_device *spi)
45*4882a593Smuzhiyun {
46*4882a593Smuzhiyun struct max7301 *ts;
47*4882a593Smuzhiyun int ret;
48*4882a593Smuzhiyun
49*4882a593Smuzhiyun /* bits_per_word cannot be configured in platform data */
50*4882a593Smuzhiyun spi->bits_per_word = 16;
51*4882a593Smuzhiyun ret = spi_setup(spi);
52*4882a593Smuzhiyun if (ret < 0)
53*4882a593Smuzhiyun return ret;
54*4882a593Smuzhiyun
55*4882a593Smuzhiyun ts = devm_kzalloc(&spi->dev, sizeof(struct max7301), GFP_KERNEL);
56*4882a593Smuzhiyun if (!ts)
57*4882a593Smuzhiyun return -ENOMEM;
58*4882a593Smuzhiyun
59*4882a593Smuzhiyun ts->read = max7301_spi_read;
60*4882a593Smuzhiyun ts->write = max7301_spi_write;
61*4882a593Smuzhiyun ts->dev = &spi->dev;
62*4882a593Smuzhiyun
63*4882a593Smuzhiyun ret = __max730x_probe(ts);
64*4882a593Smuzhiyun return ret;
65*4882a593Smuzhiyun }
66*4882a593Smuzhiyun
max7301_remove(struct spi_device * spi)67*4882a593Smuzhiyun static int max7301_remove(struct spi_device *spi)
68*4882a593Smuzhiyun {
69*4882a593Smuzhiyun return __max730x_remove(&spi->dev);
70*4882a593Smuzhiyun }
71*4882a593Smuzhiyun
72*4882a593Smuzhiyun static const struct spi_device_id max7301_id[] = {
73*4882a593Smuzhiyun { "max7301", 0 },
74*4882a593Smuzhiyun { }
75*4882a593Smuzhiyun };
76*4882a593Smuzhiyun MODULE_DEVICE_TABLE(spi, max7301_id);
77*4882a593Smuzhiyun
78*4882a593Smuzhiyun static struct spi_driver max7301_driver = {
79*4882a593Smuzhiyun .driver = {
80*4882a593Smuzhiyun .name = "max7301",
81*4882a593Smuzhiyun },
82*4882a593Smuzhiyun .probe = max7301_probe,
83*4882a593Smuzhiyun .remove = max7301_remove,
84*4882a593Smuzhiyun .id_table = max7301_id,
85*4882a593Smuzhiyun };
86*4882a593Smuzhiyun
max7301_init(void)87*4882a593Smuzhiyun static int __init max7301_init(void)
88*4882a593Smuzhiyun {
89*4882a593Smuzhiyun return spi_register_driver(&max7301_driver);
90*4882a593Smuzhiyun }
91*4882a593Smuzhiyun /* register after spi postcore initcall and before
92*4882a593Smuzhiyun * subsys initcalls that may rely on these GPIOs
93*4882a593Smuzhiyun */
94*4882a593Smuzhiyun subsys_initcall(max7301_init);
95*4882a593Smuzhiyun
max7301_exit(void)96*4882a593Smuzhiyun static void __exit max7301_exit(void)
97*4882a593Smuzhiyun {
98*4882a593Smuzhiyun spi_unregister_driver(&max7301_driver);
99*4882a593Smuzhiyun }
100*4882a593Smuzhiyun module_exit(max7301_exit);
101*4882a593Smuzhiyun
102*4882a593Smuzhiyun MODULE_AUTHOR("Juergen Beisert, Wolfram Sang");
103*4882a593Smuzhiyun MODULE_LICENSE("GPL v2");
104*4882a593Smuzhiyun MODULE_DESCRIPTION("MAX7301 GPIO-Expander");
105