drivers/i2c/busses/i2c-versatile.c

   1 /*
   2  *  i2c-versatile.c
   3  *
   4  *  Copyright (C) 2006 ARM Ltd.
   5  *  written by Russell King, Deep Blue Solutions Ltd.
   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 version 2 as
   9  * published by the Free Software Foundation.
  10  */
  11 #include <linux/kernel.h>
  12 #include <linux/module.h>
  13 #include <linux/i2c.h>
  14 #include <linux/i2c-algo-bit.h>
  15 #include <linux/init.h>
  16 #include <linux/platform_device.h>
  17 #include <linux/slab.h>
  18
  19 #include <asm/io.h>
  20
  21 #define I2C_CONTROL     0x00
  22 #define I2C_CONTROLS    0x00
  23 #define I2C_CONTROLC    0x04
  24 #define SCL             (1 << 0)
  25 #define SDA             (1 << 1)
  26
  27 struct i2c_versatile {
  28         struct i2c_adapter       adap;
  29         struct i2c_algo_bit_data algo;
  30         void __iomem             *base;
  31 };
  32
  33 static void i2c_versatile_setsda(void *data, int state)
  34 {
  35         struct i2c_versatile *i2c = data;
  36
  37         writel(SDA, i2c->base + (state ? I2C_CONTROLS : I2C_CONTROLC));
  38 }
  39
  40 static void i2c_versatile_setscl(void *data, int state)
  41 {
  42         struct i2c_versatile *i2c = data;
  43
  44         writel(SCL, i2c->base + (state ? I2C_CONTROLS : I2C_CONTROLC));
  45 }
  46
  47 static int i2c_versatile_getsda(void *data)
  48 {
  49         struct i2c_versatile *i2c = data;
  50         return !!(readl(i2c->base + I2C_CONTROL) & SDA);
  51 }
  52
  53 static int i2c_versatile_getscl(void *data)
  54 {
  55         struct i2c_versatile *i2c = data;
  56         return !!(readl(i2c->base + I2C_CONTROL) & SCL);
  57 }
  58
  59 static struct i2c_algo_bit_data i2c_versatile_algo = {
  60         .setsda = i2c_versatile_setsda,
  61         .setscl = i2c_versatile_setscl,
  62         .getsda = i2c_versatile_getsda,
  63         .getscl = i2c_versatile_getscl,
  64         .udelay = 30,
  65         .timeout = HZ,
  66 };
  67
  68 static int i2c_versatile_probe(struct platform_device *dev)
  69 {
  70         struct i2c_versatile *i2c;
  71         struct resource *r;
  72         int ret;
  73
  74         r = platform_get_resource(dev, IORESOURCE_MEM, 0);
  75         if (!r) {
  76                 ret = -EINVAL;
  77                 goto err_out;
  78         }
  79
  80         if (!request_mem_region(r->start, resource_size(r), "versatile-i2c")) {
  81                 ret = -EBUSY;
  82                 goto err_out;
  83         }
  84
  85         i2c = kzalloc(sizeof(struct i2c_versatile), GFP_KERNEL);
  86         if (!i2c) {
  87                 ret = -ENOMEM;
  88                 goto err_release;
  89         }
  90
  91         i2c->base = ioremap(r->start, resource_size(r));
  92         if (!i2c->base) {
  93                 ret = -ENOMEM;
  94                 goto err_free;
  95         }
  96
  97         writel(SCL | SDA, i2c->base + I2C_CONTROLS);
  98
  99         i2c->adap.owner = THIS_MODULE;
 100         strlcpy(i2c->adap.name, "Versatile I2C adapter", sizeof(i2c->adap.name));
 101         i2c->adap.algo_data = &i2c->algo;
 102         i2c->adap.dev.parent = &dev->dev;
 103         i2c->algo = i2c_versatile_algo;
 104         i2c->algo.data = i2c;
 105
 106         if (dev->id >= 0) {
 107                 /* static bus numbering */
 108                 i2c->adap.nr = dev->id;
 109                 ret = i2c_bit_add_numbered_bus(&i2c->adap);
 110         } else
 111                 /* dynamic bus numbering */
 112                 ret = i2c_bit_add_bus(&i2c->adap);
 113         if (ret >= 0) {
 114                 platform_set_drvdata(dev, i2c);
 115                 return 0;
 116         }
 117
 118         iounmap(i2c->base);
 119  err_free:
 120         kfree(i2c);
 121  err_release:
 122         release_mem_region(r->start, resource_size(r));
 123  err_out:
 124         return ret;
 125 }
 126
 127 static int i2c_versatile_remove(struct platform_device *dev)
 128 {
 129         struct i2c_versatile *i2c = platform_get_drvdata(dev);
 130
 131         platform_set_drvdata(dev, NULL);
 132
 133         i2c_del_adapter(&i2c->adap);
 134         return 0;
 135 }
 136
 137 static struct platform_driver i2c_versatile_driver = {
 138         .probe          = i2c_versatile_probe,
 139         .remove         = i2c_versatile_remove,
 140         .driver         = {
 141                 .name   = "versatile-i2c",
 142                 .owner  = THIS_MODULE,
 143         },
 144 };
 145
 146 static int __init i2c_versatile_init(void)
 147 {
 148         return platform_driver_register(&i2c_versatile_driver);
 149 }
 150
 151 static void __exit i2c_versatile_exit(void)
 152 {
 153         platform_driver_unregister(&i2c_versatile_driver);
 154 }
 155
 156 subsys_initcall(i2c_versatile_init);
 157 module_exit(i2c_versatile_exit);
 158
 159 MODULE_DESCRIPTION("ARM Versatile I2C bus driver");
 160 MODULE_LICENSE("GPL");
 161 MODULE_ALIAS("platform:versatile-i2c");