1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (C) 2005 Simtec Electronics
4 *	Ben Dooks <ben@simtec.co.uk>
5 *
6 * Simtec Generic I2C Controller
7*/
8
9#include <linux/kernel.h>
10#include <linux/module.h>
11#include <linux/delay.h>
12#include <linux/platform_device.h>
13#include <linux/slab.h>
14#include <linux/io.h>
15
16#include <linux/i2c.h>
17#include <linux/i2c-algo-bit.h>
18
19struct simtec_i2c_data {
20	struct resource		*ioarea;
21	void __iomem		*reg;
22	struct i2c_adapter	 adap;
23	struct i2c_algo_bit_data bit;
24};
25
26#define CMD_SET_SDA	(1<<2)
27#define CMD_SET_SCL	(1<<3)
28
29#define STATE_SDA	(1<<0)
30#define STATE_SCL	(1<<1)
31
32/* i2c bit-bus functions */
33
34static void simtec_i2c_setsda(void *pw, int state)
35{
36	struct simtec_i2c_data *pd = pw;
37	writeb(CMD_SET_SDA | (state ? STATE_SDA : 0), pd->reg);
38}
39
40static void simtec_i2c_setscl(void *pw, int state)
41{
42	struct simtec_i2c_data *pd = pw;
43	writeb(CMD_SET_SCL | (state ? STATE_SCL : 0), pd->reg);
44}
45
46static int simtec_i2c_getsda(void *pw)
47{
48	struct simtec_i2c_data *pd = pw;
49	return readb(pd->reg) & STATE_SDA ? 1 : 0;
50}
51
52static int simtec_i2c_getscl(void *pw)
53{
54	struct simtec_i2c_data *pd = pw;
55	return readb(pd->reg) & STATE_SCL ? 1 : 0;
56}
57
58/* device registration */
59
60static int simtec_i2c_probe(struct platform_device *dev)
61{
62	struct simtec_i2c_data *pd;
63	struct resource *res;
64	int size;
65	int ret;
66
67	pd = kzalloc(sizeof(struct simtec_i2c_data), GFP_KERNEL);
68	if (pd == NULL)
69		return -ENOMEM;
70
71	platform_set_drvdata(dev, pd);
72
73	res = platform_get_resource(dev, IORESOURCE_MEM, 0);
74	if (res == NULL) {
75		dev_err(&dev->dev, "cannot find IO resource\n");
76		ret = -ENOENT;
77		goto err;
78	}
79
80	size = resource_size(res);
81
82	pd->ioarea = request_mem_region(res->start, size, dev->name);
83	if (pd->ioarea == NULL) {
84		dev_err(&dev->dev, "cannot request IO\n");
85		ret = -ENXIO;
86		goto err;
87	}
88
89	pd->reg = ioremap(res->start, size);
90	if (pd->reg == NULL) {
91		dev_err(&dev->dev, "cannot map IO\n");
92		ret = -ENXIO;
93		goto err_res;
94	}
95
96	/* setup the private data */
97
98	pd->adap.owner = THIS_MODULE;
99	pd->adap.algo_data = &pd->bit;
100	pd->adap.dev.parent = &dev->dev;
101
102	strscpy(pd->adap.name, "Simtec I2C", sizeof(pd->adap.name));
103
104	pd->bit.data = pd;
105	pd->bit.setsda = simtec_i2c_setsda;
106	pd->bit.setscl = simtec_i2c_setscl;
107	pd->bit.getsda = simtec_i2c_getsda;
108	pd->bit.getscl = simtec_i2c_getscl;
109	pd->bit.timeout = HZ;
110	pd->bit.udelay = 20;
111
112	ret = i2c_bit_add_bus(&pd->adap);
113	if (ret)
114		goto err_all;
115
116	return 0;
117
118 err_all:
119	iounmap(pd->reg);
120
121 err_res:
122	release_mem_region(pd->ioarea->start, size);
123
124 err:
125	kfree(pd);
126	return ret;
127}
128
129static void simtec_i2c_remove(struct platform_device *dev)
130{
131	struct simtec_i2c_data *pd = platform_get_drvdata(dev);
132
133	i2c_del_adapter(&pd->adap);
134
135	iounmap(pd->reg);
136	release_mem_region(pd->ioarea->start, resource_size(pd->ioarea));
137	kfree(pd);
138}
139
140/* device driver */
141
142static struct platform_driver simtec_i2c_driver = {
143	.driver		= {
144		.name		= "simtec-i2c",
145	},
146	.probe		= simtec_i2c_probe,
147	.remove_new	= simtec_i2c_remove,
148};
149
150module_platform_driver(simtec_i2c_driver);
151
152MODULE_DESCRIPTION("Simtec Generic I2C Bus driver");
153MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>");
154MODULE_LICENSE("GPL");
155MODULE_ALIAS("platform:simtec-i2c");
156