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>

arch/arm/mach-realview/core.c

@@ -141,6 +141,19 @@ struct platform_device realview_smc91x_device = {
 	.resource	= realview_smc91x_resources,
 };
 
+static struct resource realview_i2c_resource = {
+	.start		= REALVIEW_I2C_BASE,
+	.end		= REALVIEW_I2C_BASE + SZ_4K - 1,
+	.flags		= IORESOURCE_MEM,
+};
+
+struct platform_device realview_i2c_device = {
+	.name		= "versatile-i2c",
+	.id		= -1,
+	.num_resources	= 1,
+	.resource	= &realview_i2c_resource,
+};
+
 #define REALVIEW_SYSMCI	(__io_address(REALVIEW_SYS_BASE) + REALVIEW_SYS_MCI_OFFSET)
 
 static unsigned int realview_mmc_status(struct device *dev)

arch/arm/mach-realview/core.h

@@ -108,6 +108,7 @@ static struct amba_device name##_device = {			\
 
 extern struct platform_device realview_flash_device;
 extern struct platform_device realview_smc91x_device;
+extern struct platform_device realview_i2c_device;
 extern struct mmc_platform_data realview_mmc0_plat_data;
 extern struct mmc_platform_data realview_mmc1_plat_data;
 extern struct clk realview_clcd_clk;

arch/arm/mach-realview/realview_eb.c

@@ -155,6 +155,7 @@ static void __init realview_eb_init(void)
 
 	platform_device_register(&realview_flash_device);
 	platform_device_register(&realview_smc91x_device);
+	platform_device_register(&realview_i2c_device);
 
 	for (i = 0; i < ARRAY_SIZE(amba_devs); i++) {
 		struct amba_device *d = amba_devs[i];

arch/arm/mach-versatile/core.c

@@ -325,6 +325,19 @@ static struct platform_device smc91x_device = {
 	.resource	= smc91x_resources,
 };
 
+static struct resource versatile_i2c_resource = {
+	.start			= VERSATILE_I2C_BASE,
+	.end			= VERSATILE_I2C_BASE + SZ_4K - 1,
+	.flags			= IORESOURCE_MEM,
+};
+
+static struct platform_device versatile_i2c_device = {
+	.name			= "versatile-i2c",
+	.id			= -1,
+	.num_resources		= 1,
+	.resource		= &versatile_i2c_resource,
+};
+
 #define VERSATILE_SYSMCI	(__io_address(VERSATILE_SYS_BASE) + VERSATILE_SYS_MCI_OFFSET)
 
 unsigned int mmc_status(struct device *dev)
@@ -775,6 +788,7 @@ void __init versatile_init(void)
 	clk_register(&versatile_clcd_clk);
 
 	platform_device_register(&versatile_flash_device);
+	platform_device_register(&versatile_i2c_device);
 	platform_device_register(&smc91x_device);
 
 	for (i = 0; i < ARRAY_SIZE(amba_devs); i++) {

drivers/i2c/busses/Kconfig

@@ -476,6 +476,17 @@ config I2C_STUB
 
 	  If you don't know what to do here, definitely say N.
 
+config I2C_VERSATILE
+	tristate "ARM Versatile/Realview I2C bus support"
+	depends on I2C && (ARCH_VERSATILE || ARCH_REALVIEW)
+	select I2C_ALGOBIT
+	help
+	  Say yes if you want to support the I2C serial bus on ARMs Versatile
+	  range of platforms.
+
+	  This driver can also be built as a module.  If so, the module
+	  will be called i2c-versatile.
+
 config I2C_VIA
 	tristate "VIA 82C586B"
 	depends on I2C && PCI && EXPERIMENTAL

drivers/i2c/busses/Makefile

@@ -40,6 +40,7 @@ obj-$(CONFIG_I2C_SIS5595)	+= i2c-sis5595.o
 obj-$(CONFIG_I2C_SIS630)	+= i2c-sis630.o
 obj-$(CONFIG_I2C_SIS96X)	+= i2c-sis96x.o
 obj-$(CONFIG_I2C_STUB)		+= i2c-stub.o
+obj-$(CONFIG_I2C_VERSATILE)	+= i2c-versatile.o
 obj-$(CONFIG_I2C_VIA)		+= i2c-via.o
 obj-$(CONFIG_I2C_VIAPRO)	+= i2c-viapro.o
 obj-$(CONFIG_I2C_VOODOO3)	+= i2c-voodoo3.o

drivers/i2c/busses/i2c-versatile.c

+/*
+ *  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");