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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  * 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/delay.h>
 24 #include <linux/platform_device.h>
 25 #include <linux/slab.h>
 26 #include <linux/io.h>
 27 
 28 #include <linux/i2c.h>
 29 #include <linux/i2c-algo-bit.h>
 30 
 31 struct simtec_i2c_data {
 32         struct resource         *ioarea;
 33         void __iomem            *reg;
 34         struct i2c_adapter       adap;
 35         struct i2c_algo_bit_data bit;
 36 };
 37 
 38 #define CMD_SET_SDA     (1<<2)
 39 #define CMD_SET_SCL     (1<<3)
 40 
 41 #define STATE_SDA       (1<<0)
 42 #define STATE_SCL       (1<<1)
 43 
 44 /* i2c bit-bus functions */
 45 
 46 static void simtec_i2c_setsda(void *pw, int state)
 47 {
 48         struct simtec_i2c_data *pd = pw;
 49         writeb(CMD_SET_SDA | (state ? STATE_SDA : 0), pd->reg);
 50 }
 51 
 52 static void simtec_i2c_setscl(void *pw, int state)
 53 {
 54         struct simtec_i2c_data *pd = pw;
 55         writeb(CMD_SET_SCL | (state ? STATE_SCL : 0), pd->reg);
 56 }
 57 
 58 static int simtec_i2c_getsda(void *pw)
 59 {
 60         struct simtec_i2c_data *pd = pw;
 61         return readb(pd->reg) & STATE_SDA ? 1 : 0;
 62 }
 63 
 64 static int simtec_i2c_getscl(void *pw)
 65 {
 66         struct simtec_i2c_data *pd = pw;
 67         return readb(pd->reg) & STATE_SCL ? 1 : 0;
 68 }
 69 
 70 /* device registration */
 71 
 72 static int simtec_i2c_probe(struct platform_device *dev)
 73 {
 74         struct simtec_i2c_data *pd;
 75         struct resource *res;
 76         int size;
 77         int ret;
 78 
 79         pd = kzalloc(sizeof(struct simtec_i2c_data), GFP_KERNEL);
 80         if (pd == NULL) {
 81                 dev_err(&dev->dev, "cannot allocate private data\n");
 82                 return -ENOMEM;
 83         }
 84 
 85         platform_set_drvdata(dev, pd);
 86 
 87         res = platform_get_resource(dev, IORESOURCE_MEM, 0);
 88         if (res == NULL) {
 89                 dev_err(&dev->dev, "cannot find IO resource\n");
 90                 ret = -ENOENT;
 91                 goto err;
 92         }
 93 
 94         size = resource_size(res);
 95 
 96         pd->ioarea = request_mem_region(res->start, size, dev->name);
 97         if (pd->ioarea == NULL) {
 98                 dev_err(&dev->dev, "cannot request IO\n");
 99                 ret = -ENXIO;
100                 goto err;
101         }
102 
103         pd->reg = ioremap(res->start, size);
104         if (pd->reg == NULL) {
105                 dev_err(&dev->dev, "cannot map IO\n");
106                 ret = -ENXIO;
107                 goto err_res;
108         }
109 
110         /* setup the private data */
111 
112         pd->adap.owner = THIS_MODULE;
113         pd->adap.algo_data = &pd->bit;
114         pd->adap.dev.parent = &dev->dev;
115 
116         strlcpy(pd->adap.name, "Simtec I2C", sizeof(pd->adap.name));
117 
118         pd->bit.data = pd;
119         pd->bit.setsda = simtec_i2c_setsda;
120         pd->bit.setscl = simtec_i2c_setscl;
121         pd->bit.getsda = simtec_i2c_getsda;
122         pd->bit.getscl = simtec_i2c_getscl;
123         pd->bit.timeout = HZ;
124         pd->bit.udelay = 20;
125 
126         ret = i2c_bit_add_bus(&pd->adap);
127         if (ret)
128                 goto err_all;
129 
130         return 0;
131 
132  err_all:
133         iounmap(pd->reg);
134 
135  err_res:
136         release_resource(pd->ioarea);
137         kfree(pd->ioarea);
138 
139  err:
140         kfree(pd);
141         return ret;
142 }
143 
144 static int simtec_i2c_remove(struct platform_device *dev)
145 {
146         struct simtec_i2c_data *pd = platform_get_drvdata(dev);
147 
148         i2c_del_adapter(&pd->adap);
149 
150         iounmap(pd->reg);
151         release_resource(pd->ioarea);
152         kfree(pd->ioarea);
153         kfree(pd);
154 
155         return 0;
156 }
157 
158 /* device driver */
159 
160 static struct platform_driver simtec_i2c_driver = {
161         .driver         = {
162                 .name           = "simtec-i2c",
163                 .owner          = THIS_MODULE,
164         },
165         .probe          = simtec_i2c_probe,
166         .remove         = simtec_i2c_remove,
167 };
168 
169 module_platform_driver(simtec_i2c_driver);
170 
171 MODULE_DESCRIPTION("Simtec Generic I2C Bus driver");
172 MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>");
173 MODULE_LICENSE("GPL");
174 MODULE_ALIAS("platform:simtec-i2c");
175 

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