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_mem_region(pd->ioarea->start, size);
 131
 132  err:
 133         kfree(pd);
 134         return ret;
 135 }
 136
 137 static int simtec_i2c_remove(struct platform_device *dev)
 138 {
 139         struct simtec_i2c_data *pd = platform_get_drvdata(dev);
 140
 141         i2c_del_adapter(&pd->adap);
 142
 143         iounmap(pd->reg);
 144         release_mem_region(pd->ioarea->start, resource_size(pd->ioarea));
 145         kfree(pd);
 146
 147         return 0;
 148 }
 149
 150 /* device driver */
 151
 152 static struct platform_driver simtec_i2c_driver = {
 153         .driver         = {
 154                 .name           = "simtec-i2c",
 155         },
 156         .probe          = simtec_i2c_probe,
 157         .remove         = simtec_i2c_remove,
 158 };
 159
 160 module_platform_driver(simtec_i2c_driver);
 161
 162 MODULE_DESCRIPTION("Simtec Generic I2C Bus driver");
 163 MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>");
 164 MODULE_LICENSE("GPL");
 165 MODULE_ALIAS("platform:simtec-i2c");