xref: /openbmc/linux/drivers/i2c/busses/i2c-simtec.c (revision 22246614)
1 /*
2  * Copyright (C) 2005 Simtec Electronics
3  *	Ben Dooks <ben@simtec.co.uk>
4  *
5  * Simtec Generic I2C Controller
6  *
7  * This program is free software; you can redistribute it and/or modify
8  * it under the terms of the GNU General Public License as published by
9  * the Free Software Foundation; either version 2 of the License
10  *
11  * This program is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14  * GNU General Public License for more details.
15  *
16  * You should have received a copy of the GNU General Public License
17  * along with this program; if not, write to the Free Software
18  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
19 */
20 
21 #include <linux/kernel.h>
22 #include <linux/module.h>
23 #include <linux/init.h>
24 #include <linux/delay.h>
25 #include <linux/platform_device.h>
26 
27 #include <linux/i2c.h>
28 #include <linux/i2c-algo-bit.h>
29 
30 #include <asm/io.h>
31 
32 struct simtec_i2c_data {
33 	struct resource		*ioarea;
34 	void __iomem		*reg;
35 	struct i2c_adapter	 adap;
36 	struct i2c_algo_bit_data bit;
37 };
38 
39 #define CMD_SET_SDA	(1<<2)
40 #define CMD_SET_SCL	(1<<3)
41 
42 #define STATE_SDA	(1<<0)
43 #define STATE_SCL	(1<<1)
44 
45 /* i2c bit-bus functions */
46 
47 static void simtec_i2c_setsda(void *pw, int state)
48 {
49 	struct simtec_i2c_data *pd = pw;
50 	writeb(CMD_SET_SDA | (state ? STATE_SDA : 0), pd->reg);
51 }
52 
53 static void simtec_i2c_setscl(void *pw, int state)
54 {
55 	struct simtec_i2c_data *pd = pw;
56 	writeb(CMD_SET_SCL | (state ? STATE_SCL : 0), pd->reg);
57 }
58 
59 static int simtec_i2c_getsda(void *pw)
60 {
61 	struct simtec_i2c_data *pd = pw;
62 	return readb(pd->reg) & STATE_SDA ? 1 : 0;
63 }
64 
65 static int simtec_i2c_getscl(void *pw)
66 {
67 	struct simtec_i2c_data *pd = pw;
68 	return readb(pd->reg) & STATE_SCL ? 1 : 0;
69 }
70 
71 /* device registration */
72 
73 static int simtec_i2c_probe(struct platform_device *dev)
74 {
75 	struct simtec_i2c_data *pd;
76 	struct resource *res;
77 	int size;
78 	int ret;
79 
80 	pd = kzalloc(sizeof(struct simtec_i2c_data), GFP_KERNEL);
81 	if (pd == NULL) {
82 		dev_err(&dev->dev, "cannot allocate private data\n");
83 		return -ENOMEM;
84 	}
85 
86 	platform_set_drvdata(dev, pd);
87 
88 	res = platform_get_resource(dev, IORESOURCE_MEM, 0);
89 	if (res == NULL) {
90 		dev_err(&dev->dev, "cannot find IO resource\n");
91 		ret = -ENOENT;
92 		goto err;
93 	}
94 
95 	size = (res->end-res->start)+1;
96 
97 	pd->ioarea = request_mem_region(res->start, size, dev->name);
98 	if (pd->ioarea == NULL) {
99 		dev_err(&dev->dev, "cannot request IO\n");
100 		ret = -ENXIO;
101 		goto err;
102 	}
103 
104 	pd->reg = ioremap(res->start, size);
105 	if (pd->reg == NULL) {
106 		dev_err(&dev->dev, "cannot map IO\n");
107 		ret = -ENXIO;
108 		goto err_res;
109 	}
110 
111 	/* setup the private data */
112 
113 	pd->adap.owner = THIS_MODULE;
114 	pd->adap.algo_data = &pd->bit;
115 	pd->adap.dev.parent = &dev->dev;
116 
117 	strlcpy(pd->adap.name, "Simtec I2C", sizeof(pd->adap.name));
118 
119 	pd->bit.data = pd;
120 	pd->bit.setsda = simtec_i2c_setsda;
121 	pd->bit.setscl = simtec_i2c_setscl;
122 	pd->bit.getsda = simtec_i2c_getsda;
123 	pd->bit.getscl = simtec_i2c_getscl;
124 	pd->bit.timeout = HZ;
125 	pd->bit.udelay = 20;
126 
127 	ret = i2c_bit_add_bus(&pd->adap);
128 	if (ret)
129 		goto err_all;
130 
131 	return 0;
132 
133  err_all:
134 	iounmap(pd->reg);
135 
136  err_res:
137 	release_resource(pd->ioarea);
138 	kfree(pd->ioarea);
139 
140  err:
141 	kfree(pd);
142 	return ret;
143 }
144 
145 static int simtec_i2c_remove(struct platform_device *dev)
146 {
147 	struct simtec_i2c_data *pd = platform_get_drvdata(dev);
148 
149 	i2c_del_adapter(&pd->adap);
150 
151 	iounmap(pd->reg);
152 	release_resource(pd->ioarea);
153 	kfree(pd->ioarea);
154 	kfree(pd);
155 
156 	return 0;
157 }
158 
159 
160 /* device driver */
161 
162 /* work with hotplug and coldplug */
163 MODULE_ALIAS("platform:simtec-i2c");
164 
165 static struct platform_driver simtec_i2c_driver = {
166 	.driver		= {
167 		.name		= "simtec-i2c",
168 		.owner		= THIS_MODULE,
169 	},
170 	.probe		= simtec_i2c_probe,
171 	.remove		= simtec_i2c_remove,
172 };
173 
174 static int __init i2c_adap_simtec_init(void)
175 {
176 	return platform_driver_register(&simtec_i2c_driver);
177 }
178 
179 static void __exit i2c_adap_simtec_exit(void)
180 {
181 	platform_driver_unregister(&simtec_i2c_driver);
182 }
183 
184 module_init(i2c_adap_simtec_init);
185 module_exit(i2c_adap_simtec_exit);
186 
187 MODULE_DESCRIPTION("Simtec Generic I2C Bus driver");
188 MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>");
189 MODULE_LICENSE("GPL");
190