i2c: New ARM Versatile/Realview bus driver

Add support for the I2C bus found on the ARM Versatile and Realview
platforms.  The I2C bus has a RTC and optionally some EEPROMs attached.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Jean Delvare <khali@linux-fr.org>

drivers/i2c/busses/i2c-versatile.c

@@ -0,0 +1,153 @@
+/*
+ *  i2c-versatile.c
+ *
+ *  Copyright (C) 2006 ARM Ltd.
+ *  written by Russell King, Deep Blue Solutions Ltd.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/i2c.h>
+#include <linux/i2c-algo-bit.h>
+#include <linux/init.h>
+#include <linux/platform_device.h>
+
+#include <asm/io.h>
+
+#define I2C_CONTROL	0x00
+#define I2C_CONTROLS	0x00
+#define I2C_CONTROLC	0x04
+#define SCL		(1 << 0)
+#define SDA		(1 << 1)
+
+struct i2c_versatile {
+	struct i2c_adapter	 adap;
+	struct i2c_algo_bit_data algo;
+	void __iomem		 *base;
+};
+
+static void i2c_versatile_setsda(void *data, int state)
+{
+	struct i2c_versatile *i2c = data;
+
+	writel(SDA, i2c->base + (state ? I2C_CONTROLS : I2C_CONTROLC));
+}
+
+static void i2c_versatile_setscl(void *data, int state)
+{
+	struct i2c_versatile *i2c = data;
+
+	writel(SCL, i2c->base + (state ? I2C_CONTROLS : I2C_CONTROLC));
+}
+
+static int i2c_versatile_getsda(void *data)
+{
+	struct i2c_versatile *i2c = data;
+	return !!(readl(i2c->base + I2C_CONTROL) & SDA);
+}
+
+static int i2c_versatile_getscl(void *data)
+{
+	struct i2c_versatile *i2c = data;
+	return !!(readl(i2c->base + I2C_CONTROL) & SCL);
+}
+
+static struct i2c_algo_bit_data i2c_versatile_algo = {
+	.setsda	= i2c_versatile_setsda,
+	.setscl = i2c_versatile_setscl,
+	.getsda	= i2c_versatile_getsda,
+	.getscl = i2c_versatile_getscl,
+	.udelay	= 30,
+	.timeout = HZ,
+};
+
+static int i2c_versatile_probe(struct platform_device *dev)
+{
+	struct i2c_versatile *i2c;
+	struct resource *r;
+	int ret;
+
+	r = platform_get_resource(dev, IORESOURCE_MEM, 0);
+	if (!r) {
+		ret = -EINVAL;
+		goto err_out;
+	}
+
+	if (!request_mem_region(r->start, r->end - r->start + 1, "versatile-i2c")) {
+		ret = -EBUSY;
+		goto err_out;
+	}
+
+	i2c = kzalloc(sizeof(struct i2c_versatile), GFP_KERNEL);
+	if (!i2c) {
+		ret = -ENOMEM;
+		goto err_release;
+	}
+
+	i2c->base = ioremap(r->start, r->end - r->start + 1);
+	if (!i2c->base) {
+		ret = -ENOMEM;
+		goto err_free;
+	}
+
+	writel(SCL | SDA, i2c->base + I2C_CONTROLS);
+
+	i2c->adap.owner = THIS_MODULE;
+	strlcpy(i2c->adap.name, "Versatile I2C adapter", sizeof(i2c->adap.name));
+	i2c->adap.algo_data = &i2c->algo;
+	i2c->adap.dev.parent = &dev->dev;
+	i2c->algo = i2c_versatile_algo;
+	i2c->algo.data = i2c;
+
+	ret = i2c_bit_add_bus(&i2c->adap);
+	if (ret >= 0) {
+		platform_set_drvdata(dev, i2c);
+		return 0;
+	}
+
+	iounmap(i2c->base);
+ err_free:
+	kfree(i2c);
+ err_release:
+	release_mem_region(r->start, r->end - r->start + 1);
+ err_out:
+	return ret;
+}
+
+static int i2c_versatile_remove(struct platform_device *dev)
+{
+	struct i2c_versatile *i2c = platform_get_drvdata(dev);
+
+	platform_set_drvdata(dev, NULL);
+
+	i2c_del_adapter(&i2c->adap);
+	return 0;
+}
+
+static struct platform_driver i2c_versatile_driver = {
+	.probe		= i2c_versatile_probe,
+	.remove		= i2c_versatile_remove,
+	.driver		= {
+		.name	= "versatile-i2c",
+		.owner	= THIS_MODULE,
+	},
+};
+
+static int __init i2c_versatile_init(void)
+{
+	return platform_driver_register(&i2c_versatile_driver);
+}
+
+static void __exit i2c_versatile_exit(void)
+{
+	platform_driver_unregister(&i2c_versatile_driver);
+}
+
+module_init(i2c_versatile_init);
+module_exit(i2c_versatile_exit);
+
+MODULE_DESCRIPTION("ARM Versatile I2C bus driver");
+MODULE_LICENSE("GPL");