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