Index: linux-3.14.30/drivers/i2c/busses/Kconfig
===================================================================
--- linux-3.14.30.orig/drivers/i2c/busses/Kconfig	2015-03-11 16:46:46.963996212 +0800
+++ linux-3.14.30/drivers/i2c/busses/Kconfig	2015-03-12 10:40:34.849574512 +0800
@@ -663,6 +663,10 @@
 	tristate "Ralink I2C Controller"
 	select OF_I2C
 
+config I2C_MT7621
+	tristate "Mt7621 I2C Controller"
+	select OF_I2C
+
 config HAVE_S3C2410_I2C
 	bool
 	help
Index: linux-3.14.30/drivers/i2c/busses/Makefile
===================================================================
--- linux-3.14.30.orig/drivers/i2c/busses/Makefile	2015-03-11 16:46:46.967996212 +0800
+++ linux-3.14.30/drivers/i2c/busses/Makefile	2015-03-11 17:52:43.008121712 +0800
@@ -64,6 +64,7 @@
 obj-$(CONFIG_I2C_PXA)		+= i2c-pxa.o
 obj-$(CONFIG_I2C_PXA_PCI)	+= i2c-pxa-pci.o
 obj-$(CONFIG_I2C_RALINK)	+= i2c-ralink.o
+obj-$(CONFIG_I2C_MT7621)	+= i2c-mt7621.o
 obj-$(CONFIG_I2C_RIIC)		+= i2c-riic.o
 obj-$(CONFIG_I2C_S3C2410)	+= i2c-s3c2410.o
 obj-$(CONFIG_I2C_S6000)		+= i2c-s6000.o
Index: linux-3.14.30/drivers/i2c/busses/i2c-mt7621.c
===================================================================
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ linux-3.14.30/drivers/i2c/busses/i2c-mt7621.c	2015-03-12 11:45:00.449759139 +0800
@@ -0,0 +1,358 @@
+/*
+ * drivers/i2c/busses/i2c-mt7621.c
+ *
+ * Copyright (C) 2013 Steven Liu <steven_liu@mediatek.com>
+ *
+ * Improve driver for i2cdetect from i2c-tools to detect i2c devices on the bus.
+ * (C) 2014 Sittisak <sittisaks@hotmail.com>
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/reset.h>
+#include <linux/delay.h>
+#include <linux/slab.h>
+#include <linux/init.h>
+#include <linux/errno.h>
+#include <linux/platform_device.h>
+#include <linux/i2c.h>
+#include <linux/io.h>
+#include <linux/err.h>
+
+#include <asm/mach-ralink/ralink_regs.h>
+
+#define REG_CONFIG_REG                       0x00
+#define REG_CLKDIV_REG                       0x04
+#define REG_DEVADDR_REG                      0x08
+#define REG_ADDR_REG                         0x0C
+#define REG_DATAOUT_REG                      0x10
+#define REG_DATAIN_REG                       0x14
+#define REG_STATUS_REG                       0x18
+#define REG_STARTXFR_REG                     0x1C
+#define REG_BYTECNT_REG                      0x20
+#define REG_SM0_IS_AUTOMODE                  0x28
+#define REG_SM0CTL0                          0x40
+
+
+#define I2C_STARTERR                         0x10
+#define I2C_ACKERR                           0x08
+#define I2C_DATARDY                          0x04
+#define I2C_SDOEMPTY                         0x02
+#define I2C_BUSY                             0x01
+
+/* I2C_CFG register bit field */
+#define I2C_CFG_ADDRLEN_8                    (7<<5)	/* 8 bits */
+#define I2C_CFG_DEVADLEN_7                   (6<<2)
+#define I2C_CFG_ADDRDIS                      (1<<1)
+#define I2C_CFG_DEVADDIS                     (1<<0)
+
+#define I2C_CFG_DEFAULT	(I2C_CFG_ADDRLEN_8 | \
+		I2C_CFG_DEVADLEN_7 | \
+		I2C_CFG_ADDRDIS)
+
+#define I2C_RETRY                            0x1000
+
+#define CLKDIV_VALUE                         333
+#define i2c_busy_loop                        (CLKDIV_VALUE*30)
+
+#define READ_CMD                             0x01
+#define WRITE_CMD                            0x00
+#define READ_BLOCK                           16
+
+#define I2C_OFFSET                           0x900
+#define RSTCTRL_OFFSET                       0x34
+
+#define MT7621_REG(x)                        (*((volatile u32 *)(x)))
+
+struct i2c_algo_mt7621_data{
+    u32 ioaddr;
+    wait_queue_head_t waitq;
+    spinlock_t lock;
+    int id;
+};
+/***********************************************************/
+
+static unsigned long clkdiv_value = CLKDIV_VALUE;
+
+static void __iomem *memsysctlbase;
+static void __iomem *membase;
+static struct i2c_adapter *adapter;
+static int i2c_id;
+
+static void rt_i2c_w32(u32 val, unsigned reg)
+{
+	iowrite32(val, membase + reg);
+}
+
+static u32 rt_i2c_r32(unsigned reg)
+{
+	return ioread32(membase + reg);
+}
+
+static void mt7621_i2c_reset(void)
+{
+	u32 val;
+	val = MT7621_REG(RSTCTRL_OFFSET+memsysctlbase);
+	val = val | (1<<16);
+	MT7621_REG(RSTCTRL_OFFSET+memsysctlbase) = val;
+    	val = val & ~(1<<16);
+	MT7621_REG(RSTCTRL_OFFSET+memsysctlbase) = val;
+	udelay(500);
+}
+static void mt7621_i2c_enable(struct i2c_msg *msg)
+{
+	rt_i2c_w32(msg->addr,REG_DEVADDR_REG);
+	rt_i2c_w32(0,REG_ADDR_REG);
+}
+
+static void i2c_master_init(void)
+{
+	u32 value;
+	/*set mt7621 i2c mode*/
+	(*((volatile u32*)(memsysctlbase+0x60))) &=~0x4;
+
+	mt7621_i2c_reset(); 
+	rt_i2c_w32(I2C_CFG_DEFAULT,REG_CONFIG_REG);    
+
+	value  = 1<< 31;
+	value |= 1<<28;
+	value |= clkdiv_value <<16;
+	value |= 1<<6;
+	value |= 1<<1;
+	rt_i2c_w32(value,REG_SM0CTL0);
+	rt_i2c_w32(1,REG_SM0_IS_AUTOMODE);//auto mode
+}
+
+
+static inline int rt_i2c_wait_rx_done(void)
+{
+	int i=0;
+	while((!(rt_i2c_r32(REG_STATUS_REG) & I2C_DATARDY)) && (i<i2c_busy_loop))
+		i++;
+	if(i>=i2c_busy_loop){
+		pr_err("err,wait for idle timeout");
+		return -ETIMEDOUT;
+	}
+	return 0;
+}
+
+static inline int rt_i2c_wait_idle(void)
+{
+	int i=0;
+	while((rt_i2c_r32(REG_STATUS_REG) & I2C_BUSY) && (i<i2c_busy_loop))
+		i++;
+	if(i>=i2c_busy_loop){
+		pr_err("err,wait for idle timeout");
+		return -ETIMEDOUT;
+	}
+	return 0;
+}
+
+static inline int rt_i2c_wait_tx_done(void)
+{
+	int i=0;
+	while((!(rt_i2c_r32(REG_STATUS_REG) & I2C_SDOEMPTY)) && (i<i2c_busy_loop))
+		i++;
+	if(i>=i2c_busy_loop){
+		pr_err("err,wait for idle timeout");
+		return -ETIMEDOUT;
+	}
+	return 0;
+}
+
+static int rt_i2c_handle_msg(struct i2c_adapter *a, struct i2c_msg* msg)
+{
+	int i = 0, j = 0, pos = 0;
+	int nblock = msg->len / READ_BLOCK;
+        int rem = msg->len % READ_BLOCK;
+
+	if (msg->flags & I2C_M_TEN) {
+		printk("10 bits addr not supported\n");
+		return -EINVAL;
+	}
+
+	if (msg->flags & I2C_M_RD) {
+		for (i = 0; i < nblock; i++) {
+	                if (rt_i2c_wait_idle())
+                        	goto ERR_TIMEOUT;
+			rt_i2c_w32(READ_BLOCK - 1, REG_BYTECNT_REG);
+			rt_i2c_w32(READ_CMD, REG_STARTXFR_REG);
+			for (j = 0; j < READ_BLOCK; j++) {
+				if (rt_i2c_wait_rx_done())
+				    goto ERR_TIMEOUT;
+                		msg->buf[pos++] = rt_i2c_r32(REG_DATAIN_REG);
+			}
+		}
+
+		if (rt_i2c_wait_idle()) {
+		    goto ERR_TIMEOUT;
+        	}
+
+		rt_i2c_w32(rem - 1, REG_BYTECNT_REG);
+		rt_i2c_w32(READ_CMD, REG_STARTXFR_REG);
+		
+        	for (i = 0; i < rem; i++) {
+			if (rt_i2c_wait_rx_done())
+                		goto ERR_TIMEOUT;
+				msg->buf[pos++] = rt_i2c_r32(REG_DATAIN_REG);
+		}
+	} else {
+		if (rt_i2c_wait_idle()) {
+	        	goto ERR_TIMEOUT;
+		}
+		rt_i2c_w32(msg->len - 1, REG_BYTECNT_REG);
+		for (i = 0; i < msg->len; i++) {
+			rt_i2c_w32(msg->buf[i], REG_DATAOUT_REG);
+			if(i == 0)
+				rt_i2c_w32(WRITE_CMD, REG_STARTXFR_REG);
+
+			if (rt_i2c_wait_tx_done())
+				goto ERR_TIMEOUT;
+		}
+	}
+
+	return 0;
+ERR_TIMEOUT:
+	return -ETIMEDOUT;
+}
+
+static int rt_i2c_master_xfer(struct i2c_adapter *a, struct i2c_msg *m, int n)
+{
+	int i = 0;
+	int ret = 0;
+	i2c_master_init();
+	mt7621_i2c_enable(m);
+
+	for (i = 0; i != n && ret==0; i++) {
+		ret = rt_i2c_handle_msg(a, &m[i]);
+
+		if (ret) {
+			return ret;
+		}
+	}
+
+	return i;
+}
+
+static u32 rt_i2c_func(struct i2c_adapter *a)
+{
+	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
+}
+
+static const struct i2c_algorithm rt_i2c_algo = {
+	.master_xfer	= rt_i2c_master_xfer,
+	.functionality	= rt_i2c_func,
+};
+
+static int rt_i2c_probe(struct platform_device *pdev)
+{
+	struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	int ret;
+	struct i2c_algo_mt7621_data *adapter_data;
+
+	adapter = kzalloc(sizeof(struct i2c_adapter), GFP_KERNEL);
+	if (!adapter) {
+		dev_err(&pdev->dev, "failed to allocate i2c_adapter\n");
+		ret =  -ENOMEM;
+        	goto out;
+	}
+	adapter_data = kzalloc(sizeof(struct i2c_algo_mt7621_data), GFP_KERNEL);
+	if (!adapter_data) {
+		ret = -ENOMEM;
+		goto free_adapter;
+	}
+    
+	membase = devm_request_and_ioremap(&pdev->dev, res);
+	if (IS_ERR(membase)){
+		ret = -EBUSY;
+		goto free_both;
+    	}
+	memsysctlbase = membase - I2C_OFFSET;
+
+	adapter_data->id = i2c_id++;
+	strlcpy(adapter->name, dev_name(&pdev->dev), sizeof(adapter->name));
+
+	adapter->owner = THIS_MODULE;
+	adapter->nr = pdev->id;
+	adapter->timeout = HZ;
+	adapter->algo = &rt_i2c_algo;
+	adapter->class = I2C_CLASS_HWMON | I2C_CLASS_SPD;
+	adapter->dev.parent = &pdev->dev;
+	adapter->dev.of_node = pdev->dev.of_node;
+
+	init_waitqueue_head(&adapter_data->waitq);
+	spin_lock_init(&adapter_data->lock);
+
+	platform_set_drvdata(pdev, adapter);
+	adapter->algo_data = adapter_data;
+
+	ret = i2c_add_numbered_adapter(adapter);
+	if (ret)
+		return ret;
+
+	printk("MT7621A i2c add adapter is ok\n");
+
+	return 0;
+free_both:
+	kfree(adapter_data);
+	free_adapter:
+	kfree(adapter);
+out:
+	return ret;
+}
+
+static int rt_i2c_remove(struct platform_device *pdev)
+{
+	struct i2c_algo_mt7621_data *adapter_data = (struct i2c_algo_mt7621_data *)adapter->algo_data;
+	release_mem_region((resource_size_t)membase,0x100);
+	kfree(adapter_data);
+	kfree(adapter);
+	platform_set_drvdata(pdev, NULL);
+
+	return 0;
+}
+
+static const struct of_device_id i2c_rt_dt_ids[] = {
+	{ .compatible = "ralink,i2c-mt7621", },
+	{ /* sentinel */ }
+};
+
+MODULE_DEVICE_TABLE(of, i2c_rt_dt_ids);
+
+static struct platform_driver rt_i2c_driver = {
+	.probe		= rt_i2c_probe,
+	.remove		= rt_i2c_remove,
+	.driver		= {
+		.owner	= THIS_MODULE,
+		.name	= "i2c-mt7621",
+		.of_match_table = i2c_rt_dt_ids,
+	},
+};
+
+static int __init i2c_rt_init (void)
+{
+	return platform_driver_register(&rt_i2c_driver);
+}
+
+static void __exit i2c_rt_exit (void)
+{
+	platform_driver_unregister(&rt_i2c_driver);
+}
+module_init (i2c_rt_init);
+module_exit (i2c_rt_exit);
+
+MODULE_AUTHOR("Steven Liu <steven_liu@mediatek.com>");
+MODULE_DESCRIPTION("MT7621 I2c host driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:MT7621-I2C");
