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");