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>

3 files changed, 165 insertions, 0 deletions

diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
index ab398b700586..e1989f3a2684 100644
--- a/drivers/i2c/busses/Kconfig
+++ b/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
diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
index a82b6bfad046..37196c1d0794 100644
--- a/drivers/i2c/busses/Makefile
+++ b/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
diff --git a/drivers/i2c/busses/i2c-versatile.c b/drivers/i2c/busses/i2c-versatile.c
new file mode 100644
index 000000000000..081d9578ce10
--- /dev/null
+++ b/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");