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/init.h>
  24 #include <linux/delay.h>
  25 #include <linux/platform_device.h>
  26 #include <linux/slab.h>
  27
  28 #include <linux/i2c.h>
  29 #include <linux/i2c-algo-bit.h>
  30
  31 #include <asm/io.h>
  32
  33 struct simtec_i2c_data {
  34         struct resource         *ioarea;
  35         void __iomem            *reg;
  36         struct i2c_adapter       adap;
  37         struct i2c_algo_bit_data bit;
  38 };
  39
  40 #define CMD_SET_SDA     (1<<2)
  41 #define CMD_SET_SCL     (1<<3)
  42
  43 #define STATE_SDA       (1<<0)
  44 #define STATE_SCL       (1<<1)
  45
  46 /* i2c bit-bus functions */
  47
  48 static void simtec_i2c_setsda(void *pw, int state)
  49 {
  50         struct simtec_i2c_data *pd = pw;
  51         writeb(CMD_SET_SDA | (state ? STATE_SDA : 0), pd->reg);
  52 }
  53
  54 static void simtec_i2c_setscl(void *pw, int state)
  55 {
  56         struct simtec_i2c_data *pd = pw;
  57         writeb(CMD_SET_SCL | (state ? STATE_SCL : 0), pd->reg);
  58 }
  59
  60 static int simtec_i2c_getsda(void *pw)
  61 {
  62         struct simtec_i2c_data *pd = pw;
  63         return readb(pd->reg) & STATE_SDA ? 1 : 0;
  64 }
  65
  66 static int simtec_i2c_getscl(void *pw)
  67 {
  68         struct simtec_i2c_data *pd = pw;
  69         return readb(pd->reg) & STATE_SCL ? 1 : 0;
  70 }
  71
  72 /* device registration */
  73
  74 static int simtec_i2c_probe(struct platform_device *dev)
  75 {
  76         struct simtec_i2c_data *pd;
  77         struct resource *res;
  78         int size;
  79         int ret;
  80
  81         pd = kzalloc(sizeof(struct simtec_i2c_data), GFP_KERNEL);
  82         if (pd == NULL) {
  83                 dev_err(&dev->dev, "cannot allocate private data\n");
  84                 return -ENOMEM;
  85         }
  86
  87         platform_set_drvdata(dev, pd);
  88
  89         res = platform_get_resource(dev, IORESOURCE_MEM, 0);
  90         if (res == NULL) {
  91                 dev_err(&dev->dev, "cannot find IO resource\n");
  92                 ret = -ENOENT;
  93                 goto err;
  94         }
  95
  96         size = resource_size(res);
  97
  98         pd->ioarea = request_mem_region(res->start, size, dev->name);
  99         if (pd->ioarea == NULL) {
 100                 dev_err(&dev->dev, "cannot request IO\n");
 101                 ret = -ENXIO;
 102                 goto err;
 103         }
 104
 105         pd->reg = ioremap(res->start, size);
 106         if (pd->reg == NULL) {
 107                 dev_err(&dev->dev, "cannot map IO\n");
 108                 ret = -ENXIO;
 109                 goto err_res;
 110         }
 111
 112         /* setup the private data */
 113
 114         pd->adap.owner = THIS_MODULE;
 115         pd->adap.algo_data = &pd->bit;
 116         pd->adap.dev.parent = &dev->dev;
 117
 118         strlcpy(pd->adap.name, "Simtec I2C", sizeof(pd->adap.name));
 119
 120         pd->bit.data = pd;
 121         pd->bit.setsda = simtec_i2c_setsda;
 122         pd->bit.setscl = simtec_i2c_setscl;
 123         pd->bit.getsda = simtec_i2c_getsda;
 124         pd->bit.getscl = simtec_i2c_getscl;
 125         pd->bit.timeout = HZ;
 126         pd->bit.udelay = 20;
 127
 128         ret = i2c_bit_add_bus(&pd->adap);
 129         if (ret)
 130                 goto err_all;
 131
 132         return 0;
 133
 134  err_all:
 135         iounmap(pd->reg);
 136
 137  err_res:
 138         release_resource(pd->ioarea);
 139         kfree(pd->ioarea);
 140
 141  err:
 142         kfree(pd);
 143         return ret;
 144 }
 145
 146 static int simtec_i2c_remove(struct platform_device *dev)
 147 {
 148         struct simtec_i2c_data *pd = platform_get_drvdata(dev);
 149
 150         i2c_del_adapter(&pd->adap);
 151
 152         iounmap(pd->reg);
 153         release_resource(pd->ioarea);
 154         kfree(pd->ioarea);
 155         kfree(pd);
 156
 157         return 0;
 158 }
 159
 160
 161 /* device driver */
 162
 163 /* work with hotplug and coldplug */
 164 MODULE_ALIAS("platform:simtec-i2c");
 165
 166 static struct platform_driver simtec_i2c_driver = {
 167         .driver         = {
 168                 .name           = "simtec-i2c",
 169                 .owner          = THIS_MODULE,
 170         },
 171         .probe          = simtec_i2c_probe,
 172         .remove         = simtec_i2c_remove,
 173 };
 174
 175 static int __init i2c_adap_simtec_init(void)
 176 {
 177         return platform_driver_register(&simtec_i2c_driver);
 178 }
 179
 180 static void __exit i2c_adap_simtec_exit(void)
 181 {
 182         platform_driver_unregister(&simtec_i2c_driver);
 183 }
 184
 185 module_init(i2c_adap_simtec_init);
 186 module_exit(i2c_adap_simtec_exit);
 187
 188 MODULE_DESCRIPTION("Simtec Generic I2C Bus driver");
 189 MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>");
 190 MODULE_LICENSE("GPL");