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
17 #include <linux/kernel.h>
18 #include <linux/module.h>
19 #include <linux/delay.h>
20 #include <linux/platform_device.h>
21 #include <linux/slab.h>
22 #include <linux/io.h>
23
24 #include <linux/i2c.h>
25 #include <linux/i2c-algo-bit.h>
26
27 struct simtec_i2c_data {
28 struct resource *ioarea;
29 void __iomem *reg;
30 struct i2c_adapter adap;
31 struct i2c_algo_bit_data bit;
32 };
33
34 #define CMD_SET_SDA (1<<2)
35 #define CMD_SET_SCL (1<<3)
36
37 #define STATE_SDA (1<<0)
38 #define STATE_SCL (1<<1)
39
40 /* i2c bit-bus functions */
41
simtec_i2c_setsda(void * pw,int state)42 static void simtec_i2c_setsda(void *pw, int state)
43 {
44 struct simtec_i2c_data *pd = pw;
45 writeb(CMD_SET_SDA | (state ? STATE_SDA : 0), pd->reg);
46 }
47
simtec_i2c_setscl(void * pw,int state)48 static void simtec_i2c_setscl(void *pw, int state)
49 {
50 struct simtec_i2c_data *pd = pw;
51 writeb(CMD_SET_SCL | (state ? STATE_SCL : 0), pd->reg);
52 }
53
simtec_i2c_getsda(void * pw)54 static int simtec_i2c_getsda(void *pw)
55 {
56 struct simtec_i2c_data *pd = pw;
57 return readb(pd->reg) & STATE_SDA ? 1 : 0;
58 }
59
simtec_i2c_getscl(void * pw)60 static int simtec_i2c_getscl(void *pw)
61 {
62 struct simtec_i2c_data *pd = pw;
63 return readb(pd->reg) & STATE_SCL ? 1 : 0;
64 }
65
66 /* device registration */
67
simtec_i2c_probe(struct platform_device * dev)68 static int simtec_i2c_probe(struct platform_device *dev)
69 {
70 struct simtec_i2c_data *pd;
71 struct resource *res;
72 int size;
73 int ret;
74
75 pd = kzalloc(sizeof(struct simtec_i2c_data), GFP_KERNEL);
76 if (pd == NULL)
77 return -ENOMEM;
78
79 platform_set_drvdata(dev, pd);
80
81 res = platform_get_resource(dev, IORESOURCE_MEM, 0);
82 if (res == NULL) {
83 dev_err(&dev->dev, "cannot find IO resource\n");
84 ret = -ENOENT;
85 goto err;
86 }
87
88 size = resource_size(res);
89
90 pd->ioarea = request_mem_region(res->start, size, dev->name);
91 if (pd->ioarea == NULL) {
92 dev_err(&dev->dev, "cannot request IO\n");
93 ret = -ENXIO;
94 goto err;
95 }
96
97 pd->reg = ioremap(res->start, size);
98 if (pd->reg == NULL) {
99 dev_err(&dev->dev, "cannot map IO\n");
100 ret = -ENXIO;
101 goto err_res;
102 }
103
104 /* setup the private data */
105
106 pd->adap.owner = THIS_MODULE;
107 pd->adap.algo_data = &pd->bit;
108 pd->adap.dev.parent = &dev->dev;
109
110 strlcpy(pd->adap.name, "Simtec I2C", sizeof(pd->adap.name));
111
112 pd->bit.data = pd;
113 pd->bit.setsda = simtec_i2c_setsda;
114 pd->bit.setscl = simtec_i2c_setscl;
115 pd->bit.getsda = simtec_i2c_getsda;
116 pd->bit.getscl = simtec_i2c_getscl;
117 pd->bit.timeout = HZ;
118 pd->bit.udelay = 20;
119
120 ret = i2c_bit_add_bus(&pd->adap);
121 if (ret)
122 goto err_all;
123
124 return 0;
125
126 err_all:
127 iounmap(pd->reg);
128
129 err_res:
130 release_resource(pd->ioarea);
131 kfree(pd->ioarea);
132
133 err:
134 kfree(pd);
135 return ret;
136 }
137
simtec_i2c_remove(struct platform_device * dev)138 static int simtec_i2c_remove(struct platform_device *dev)
139 {
140 struct simtec_i2c_data *pd = platform_get_drvdata(dev);
141
142 i2c_del_adapter(&pd->adap);
143
144 iounmap(pd->reg);
145 release_resource(pd->ioarea);
146 kfree(pd->ioarea);
147 kfree(pd);
148
149 return 0;
150 }
151
152 /* device driver */
153
154 static struct platform_driver simtec_i2c_driver = {
155 .driver = {
156 .name = "simtec-i2c",
157 },
158 .probe = simtec_i2c_probe,
159 .remove = simtec_i2c_remove,
160 };
161
162 module_platform_driver(simtec_i2c_driver);
163
164 MODULE_DESCRIPTION("Simtec Generic I2C Bus driver");
165 MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>");
166 MODULE_LICENSE("GPL");
167 MODULE_ALIAS("platform:simtec-i2c");
168