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Linux/drivers/i2c/busses/i2c-simtec.c

  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 
 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);
 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 
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                 .owner          = THIS_MODULE,
158         },
159         .probe          = simtec_i2c_probe,
160         .remove         = simtec_i2c_remove,
161 };
162 
163 module_platform_driver(simtec_i2c_driver);
164 
165 MODULE_DESCRIPTION("Simtec Generic I2C Bus driver");
166 MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>");
167 MODULE_LICENSE("GPL");
168 MODULE_ALIAS("platform:simtec-i2c");
169 

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