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bcda9f1e BD |
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. | |
bcda9f1e BD |
15 | */ |
16 | ||
17 | #include <linux/kernel.h> | |
18 | #include <linux/module.h> | |
bcda9f1e BD |
19 | #include <linux/delay.h> |
20 | #include <linux/platform_device.h> | |
5a0e3ad6 | 21 | #include <linux/slab.h> |
21782180 | 22 | #include <linux/io.h> |
bcda9f1e BD |
23 | |
24 | #include <linux/i2c.h> | |
25 | #include <linux/i2c-algo-bit.h> | |
26 | ||
bcda9f1e BD |
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 | ||
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 | ||
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 | ||
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 | ||
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 | ||
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); | |
46797a2a | 76 | if (pd == NULL) |
bcda9f1e | 77 | return -ENOMEM; |
bcda9f1e BD |
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 | ||
59330825 | 88 | size = resource_size(res); |
bcda9f1e BD |
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 | ||
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 | ||
bcda9f1e BD |
152 | /* device driver */ |
153 | ||
154 | static struct platform_driver simtec_i2c_driver = { | |
155 | .driver = { | |
156 | .name = "simtec-i2c", | |
bcda9f1e BD |
157 | }, |
158 | .probe = simtec_i2c_probe, | |
159 | .remove = simtec_i2c_remove, | |
160 | }; | |
161 | ||
a3664b51 | 162 | module_platform_driver(simtec_i2c_driver); |
bcda9f1e BD |
163 | |
164 | MODULE_DESCRIPTION("Simtec Generic I2C Bus driver"); | |
165 | MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>"); | |
166 | MODULE_LICENSE("GPL"); | |
a3664b51 | 167 | MODULE_ALIAS("platform:simtec-i2c"); |