I2C: mediatek: Add driver for MediaTek I2C controller
authorXudong Chen <xudong.chen@mediatek.com>
Thu, 21 May 2015 08:53:28 +0000 (16:53 +0800)
committerWolfram Sang <wsa@the-dreams.de>
Sun, 31 May 2015 23:28:09 +0000 (08:28 +0900)
The mediatek SoCs have I2C controller that handle I2C transfer.
This patch include common I2C bus driver.
This driver is compatible with I2C controller on mt65xx/mt81xx.

Signed-off-by: Xudong Chen <xudong.chen@mediatek.com>
Signed-off-by: Liguo Zhang <liguo.zhang@mediatek.com>
Signed-off-by: Eddie Huang <eddie.huang@mediatek.com>
Acked-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Documentation/devicetree/bindings/i2c/i2c-mt6577.txt [new file with mode: 0644]
drivers/i2c/busses/Kconfig
drivers/i2c/busses/Makefile
drivers/i2c/busses/i2c-mt65xx.c [new file with mode: 0644]

diff --git a/Documentation/devicetree/bindings/i2c/i2c-mt6577.txt b/Documentation/devicetree/bindings/i2c/i2c-mt6577.txt
new file mode 100644 (file)
index 0000000..0ce6fa3
--- /dev/null
@@ -0,0 +1,41 @@
+* Mediatek's I2C controller
+
+The Mediatek's I2C controller is used to interface with I2C devices.
+
+Required properties:
+  - compatible: value should be either of the following.
+      (a) "mediatek,mt6577-i2c", for i2c compatible with mt6577 i2c.
+      (b) "mediatek,mt6589-i2c", for i2c compatible with mt6589 i2c.
+      (c) "mediatek,mt8127-i2c", for i2c compatible with mt8127 i2c.
+      (d) "mediatek,mt8135-i2c", for i2c compatible with mt8135 i2c.
+      (e) "mediatek,mt8173-i2c", for i2c compatible with mt8173 i2c.
+  - reg: physical base address of the controller and dma base, length of memory
+    mapped region.
+  - interrupts: interrupt number to the cpu.
+  - clock-div: the fixed value for frequency divider of clock source in i2c
+    module. Each IC may be different.
+  - clocks: clock name from clock manager
+  - clock-names: Must include "main" and "dma", if enable have-pmic need include
+    "pmic" extra.
+
+Optional properties:
+  - clock-frequency: Frequency in Hz of the bus when transfer, the default value
+    is 100000.
+  - mediatek,have-pmic: platform can control i2c form special pmic side.
+    Only mt6589 and mt8135 support this feature.
+  - mediatek,use-push-pull: IO config use push-pull mode.
+
+Example:
+
+       i2c0: i2c@1100d000 {
+                       compatible = "mediatek,mt6577-i2c";
+                       reg = <0x1100d000 0x70>,
+                             <0x11000300 0x80>;
+                       interrupts = <GIC_SPI 44 IRQ_TYPE_LEVEL_LOW>;
+                       clock-frequency = <400000>;
+                       mediatek,have-pmic;
+                       clock-div = <16>;
+                       clocks = <&i2c0_ck>, <&ap_dma_ck>;
+                       clock-names = "main", "dma";
+       };
+
index 1d759c3767e769f0b43da0bbbaf4a2ade26797b0..8a639dce517324d5ae968f91dde5ee4c68fe56f0 100644 (file)
@@ -620,6 +620,15 @@ config I2C_MPC
          This driver can also be built as a module.  If so, the module
          will be called i2c-mpc.
 
+config I2C_MT65XX
+       tristate "MediaTek I2C adapter"
+       depends on ARCH_MEDIATEK || COMPILE_TEST
+       help
+         This selects the MediaTek(R) Integrated Inter Circuit bus driver
+         for MT65xx and MT81xx.
+         If you want to use MediaTek(R) I2C interface, say Y or M here.
+         If unsure, say N.
+
 config I2C_MV64XXX
        tristate "Marvell mv64xxx I2C Controller"
        depends on MV64X60 || PLAT_ORION || ARCH_SUNXI
index d8093022ee4c062c94fabd7b9c11d191282e68c7..65995423c680135021d1adcf0711bc6b5e495c3b 100644 (file)
@@ -60,6 +60,7 @@ obj-$(CONFIG_I2C_JZ4780)      += i2c-jz4780.o
 obj-$(CONFIG_I2C_KEMPLD)       += i2c-kempld.o
 obj-$(CONFIG_I2C_MESON)                += i2c-meson.o
 obj-$(CONFIG_I2C_MPC)          += i2c-mpc.o
+obj-$(CONFIG_I2C_MT65XX)       += i2c-mt65xx.o
 obj-$(CONFIG_I2C_MV64XXX)      += i2c-mv64xxx.o
 obj-$(CONFIG_I2C_MXS)          += i2c-mxs.o
 obj-$(CONFIG_I2C_NOMADIK)      += i2c-nomadik.o
diff --git a/drivers/i2c/busses/i2c-mt65xx.c b/drivers/i2c/busses/i2c-mt65xx.c
new file mode 100644 (file)
index 0000000..b1d2d7c
--- /dev/null
@@ -0,0 +1,686 @@
+/*
+ * Copyright (c) 2014 MediaTek Inc.
+ * Author: Xudong Chen <xudong.chen@mediatek.com>
+ *
+ * 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.
+ *
+ * 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/clk.h>
+#include <linux/completion.h>
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/dma-mapping.h>
+#include <linux/err.h>
+#include <linux/errno.h>
+#include <linux/i2c.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/module.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/platform_device.h>
+#include <linux/scatterlist.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+
+#define I2C_HS_NACKERR                 (1 << 2)
+#define I2C_ACKERR                     (1 << 1)
+#define I2C_TRANSAC_COMP               (1 << 0)
+#define I2C_TRANSAC_START              (1 << 0)
+#define I2C_DCM_DISABLE                        0x0000
+#define I2C_IO_CONFIG_OPEN_DRAIN       0x0003
+#define I2C_IO_CONFIG_PUSH_PULL                0x0000
+#define I2C_SOFT_RST                   0x0001
+#define I2C_FIFO_ADDR_CLR              0x0001
+#define I2C_DELAY_LEN                  0x0002
+#define I2C_ST_START_CON               0x8001
+#define I2C_FS_START_CON               0x1800
+#define I2C_TIME_CLR_VALUE             0x0000
+#define I2C_TIME_DEFAULT_VALUE         0x0003
+#define I2C_FS_TIME_INIT_VALUE         0x1303
+#define I2C_WRRD_TRANAC_VALUE          0x0002
+#define I2C_RD_TRANAC_VALUE            0x0001
+
+#define I2C_DMA_CON_TX                 0x0000
+#define I2C_DMA_CON_RX                 0x0001
+#define I2C_DMA_START_EN               0x0001
+#define I2C_DMA_INT_FLAG_NONE          0x0000
+#define I2C_DMA_CLR_FLAG               0x0000
+
+#define I2C_DEFAULT_SPEED              100000  /* hz */
+#define MAX_FS_MODE_SPEED              400000
+#define MAX_HS_MODE_SPEED              3400000
+#define MAX_SAMPLE_CNT_DIV             8
+#define MAX_STEP_CNT_DIV               64
+#define MAX_HS_STEP_CNT_DIV            8
+
+#define I2C_CONTROL_RS                  (0x1 << 1)
+#define I2C_CONTROL_DMA_EN              (0x1 << 2)
+#define I2C_CONTROL_CLK_EXT_EN          (0x1 << 3)
+#define I2C_CONTROL_DIR_CHANGE          (0x1 << 4)
+#define I2C_CONTROL_ACKERR_DET_EN       (0x1 << 5)
+#define I2C_CONTROL_TRANSFER_LEN_CHANGE (0x1 << 6)
+#define I2C_CONTROL_WRAPPER             (0x1 << 0)
+
+#define I2C_DRV_NAME           "i2c-mt65xx"
+
+enum DMA_REGS_OFFSET {
+       OFFSET_INT_FLAG = 0x0,
+       OFFSET_INT_EN = 0x04,
+       OFFSET_EN = 0x08,
+       OFFSET_CON = 0x18,
+       OFFSET_TX_MEM_ADDR = 0x1c,
+       OFFSET_RX_MEM_ADDR = 0x20,
+       OFFSET_TX_LEN = 0x24,
+       OFFSET_RX_LEN = 0x28,
+};
+
+enum i2c_trans_st_rs {
+       I2C_TRANS_STOP = 0,
+       I2C_TRANS_REPEATED_START,
+};
+
+enum mtk_trans_op {
+       I2C_MASTER_WR = 1,
+       I2C_MASTER_RD,
+       I2C_MASTER_WRRD,
+};
+
+enum I2C_REGS_OFFSET {
+       OFFSET_DATA_PORT = 0x0,
+       OFFSET_SLAVE_ADDR = 0x04,
+       OFFSET_INTR_MASK = 0x08,
+       OFFSET_INTR_STAT = 0x0c,
+       OFFSET_CONTROL = 0x10,
+       OFFSET_TRANSFER_LEN = 0x14,
+       OFFSET_TRANSAC_LEN = 0x18,
+       OFFSET_DELAY_LEN = 0x1c,
+       OFFSET_TIMING = 0x20,
+       OFFSET_START = 0x24,
+       OFFSET_EXT_CONF = 0x28,
+       OFFSET_FIFO_STAT = 0x30,
+       OFFSET_FIFO_THRESH = 0x34,
+       OFFSET_FIFO_ADDR_CLR = 0x38,
+       OFFSET_IO_CONFIG = 0x40,
+       OFFSET_RSV_DEBUG = 0x44,
+       OFFSET_HS = 0x48,
+       OFFSET_SOFTRESET = 0x50,
+       OFFSET_DCM_EN = 0x54,
+       OFFSET_PATH_DIR = 0x60,
+       OFFSET_DEBUGSTAT = 0x64,
+       OFFSET_DEBUGCTRL = 0x68,
+       OFFSET_TRANSFER_LEN_AUX = 0x6c,
+};
+
+struct mtk_i2c_compatible {
+       const struct i2c_adapter_quirks *quirks;
+       unsigned char pmic_i2c: 1;
+       unsigned char dcm: 1;
+};
+
+struct mtk_i2c {
+       struct i2c_adapter adap;        /* i2c host adapter */
+       struct device *dev;
+       struct completion msg_complete;
+
+       /* set in i2c probe */
+       void __iomem *base;             /* i2c base addr */
+       void __iomem *pdmabase;         /* dma base address*/
+       struct clk *clk_main;           /* main clock for i2c bus */
+       struct clk *clk_dma;            /* DMA clock for i2c via DMA */
+       struct clk *clk_pmic;           /* PMIC clock for i2c from PMIC */
+       bool have_pmic;                 /* can use i2c pins from PMIC */
+       bool use_push_pull;             /* IO config push-pull mode */
+
+       u16 irq_stat;                   /* interrupt status */
+       unsigned int speed_hz;          /* The speed in transfer */
+       enum mtk_trans_op op;
+       u16 timing_reg;
+       u16 high_speed_reg;
+       const struct mtk_i2c_compatible *dev_comp;
+};
+
+static const struct i2c_adapter_quirks mt6577_i2c_quirks = {
+       .flags = I2C_AQ_COMB_WRITE_THEN_READ,
+       .max_num_msgs = 1,
+       .max_write_len = 255,
+       .max_read_len = 255,
+       .max_comb_1st_msg_len = 255,
+       .max_comb_2nd_msg_len = 31,
+};
+
+static const struct mtk_i2c_compatible mt6577_compat = {
+       .quirks = &mt6577_i2c_quirks,
+       .pmic_i2c = 0,
+       .dcm = 1,
+};
+
+static const struct mtk_i2c_compatible mt6589_compat = {
+       .quirks = &mt6577_i2c_quirks,
+       .pmic_i2c = 1,
+       .dcm = 0,
+};
+
+static const struct of_device_id mtk_i2c_of_match[] = {
+       { .compatible = "mediatek,mt6577-i2c", .data = &mt6577_compat },
+       { .compatible = "mediatek,mt6589-i2c", .data = &mt6589_compat },
+       {}
+};
+MODULE_DEVICE_TABLE(of, mtk_i2c_of_match);
+
+static int mtk_i2c_clock_enable(struct mtk_i2c *i2c)
+{
+       int ret;
+
+       ret = clk_prepare_enable(i2c->clk_dma);
+       if (ret)
+               return ret;
+
+       ret = clk_prepare_enable(i2c->clk_main);
+       if (ret)
+               goto err_main;
+
+       if (i2c->have_pmic) {
+               ret = clk_prepare_enable(i2c->clk_pmic);
+               if (ret)
+                       goto err_pmic;
+       }
+       return 0;
+
+err_pmic:
+       clk_disable_unprepare(i2c->clk_main);
+err_main:
+       clk_disable_unprepare(i2c->clk_dma);
+
+       return ret;
+}
+
+static void mtk_i2c_clock_disable(struct mtk_i2c *i2c)
+{
+       if (i2c->have_pmic)
+               clk_disable_unprepare(i2c->clk_pmic);
+
+       clk_disable_unprepare(i2c->clk_main);
+       clk_disable_unprepare(i2c->clk_dma);
+}
+
+static void mtk_i2c_init_hw(struct mtk_i2c *i2c)
+{
+       u16 control_reg;
+
+       writew(I2C_SOFT_RST, i2c->base + OFFSET_SOFTRESET);
+
+       /* Set ioconfig */
+       if (i2c->use_push_pull)
+               writew(I2C_IO_CONFIG_PUSH_PULL, i2c->base + OFFSET_IO_CONFIG);
+       else
+               writew(I2C_IO_CONFIG_OPEN_DRAIN, i2c->base + OFFSET_IO_CONFIG);
+
+       if (i2c->dev_comp->dcm)
+               writew(I2C_DCM_DISABLE, i2c->base + OFFSET_DCM_EN);
+
+       writew(i2c->timing_reg, i2c->base + OFFSET_TIMING);
+       writew(i2c->high_speed_reg, i2c->base + OFFSET_HS);
+
+       /* If use i2c pin from PMIC mt6397 side, need set PATH_DIR first */
+       if (i2c->have_pmic)
+               writew(I2C_CONTROL_WRAPPER, i2c->base + OFFSET_PATH_DIR);
+
+       control_reg = I2C_CONTROL_ACKERR_DET_EN |
+                     I2C_CONTROL_CLK_EXT_EN | I2C_CONTROL_DMA_EN;
+       writew(control_reg, i2c->base + OFFSET_CONTROL);
+       writew(I2C_DELAY_LEN, i2c->base + OFFSET_DELAY_LEN);
+}
+
+/*
+ * Calculate i2c port speed
+ *
+ * Hardware design:
+ * i2c_bus_freq = parent_clk / (clock_div * 2 * sample_cnt * step_cnt)
+ * clock_div: fixed in hardware, but may be various in different SoCs
+ *
+ * The calculation want to pick the highest bus frequency that is still
+ * less than or equal to i2c->speed_hz. The calculation try to get
+ * sample_cnt and step_cn
+ */
+static int mtk_i2c_set_speed(struct mtk_i2c *i2c, unsigned int parent_clk,
+                            unsigned int clock_div)
+{
+       unsigned int clk_src;
+       unsigned int step_cnt;
+       unsigned int sample_cnt;
+       unsigned int max_step_cnt;
+       unsigned int target_speed;
+       unsigned int base_sample_cnt = MAX_SAMPLE_CNT_DIV;
+       unsigned int base_step_cnt;
+       unsigned int opt_div;
+       unsigned int best_mul;
+       unsigned int cnt_mul;
+
+       clk_src = parent_clk / clock_div;
+       target_speed = i2c->speed_hz;
+
+       if (target_speed > MAX_HS_MODE_SPEED)
+               target_speed = MAX_HS_MODE_SPEED;
+
+       if (target_speed > MAX_FS_MODE_SPEED)
+               max_step_cnt = MAX_HS_STEP_CNT_DIV;
+       else
+               max_step_cnt = MAX_STEP_CNT_DIV;
+
+       base_step_cnt = max_step_cnt;
+       /* Find the best combination */
+       opt_div = DIV_ROUND_UP(clk_src >> 1, target_speed);
+       best_mul = MAX_SAMPLE_CNT_DIV * max_step_cnt;
+
+       /* Search for the best pair (sample_cnt, step_cnt) with
+        * 0 < sample_cnt < MAX_SAMPLE_CNT_DIV
+        * 0 < step_cnt < max_step_cnt
+        * sample_cnt * step_cnt >= opt_div
+        * optimizing for sample_cnt * step_cnt being minimal
+        */
+       for (sample_cnt = 1; sample_cnt <= MAX_SAMPLE_CNT_DIV; sample_cnt++) {
+               step_cnt = DIV_ROUND_UP(opt_div, sample_cnt);
+               cnt_mul = step_cnt * sample_cnt;
+               if (step_cnt > max_step_cnt)
+                       continue;
+
+               if (cnt_mul < best_mul) {
+                       best_mul = cnt_mul;
+                       base_sample_cnt = sample_cnt;
+                       base_step_cnt = step_cnt;
+                       if (best_mul == opt_div)
+                               break;
+               }
+       }
+
+       sample_cnt = base_sample_cnt;
+       step_cnt = base_step_cnt;
+
+       if ((clk_src / (2 * sample_cnt * step_cnt)) > target_speed) {
+               /* In this case, hardware can't support such
+                * low i2c_bus_freq
+                */
+               dev_dbg(i2c->dev, "Unsupported speed (%uhz)\n", target_speed);
+               return -EINVAL;
+       }
+
+       step_cnt--;
+       sample_cnt--;
+
+       if (target_speed > MAX_FS_MODE_SPEED) {
+               /* Set the high speed mode register */
+               i2c->timing_reg = I2C_FS_TIME_INIT_VALUE;
+               i2c->high_speed_reg = I2C_TIME_DEFAULT_VALUE |
+                       (sample_cnt << 12) | (step_cnt << 8);
+       } else {
+               i2c->timing_reg = (sample_cnt << 8) | (step_cnt << 0);
+               /* Disable the high speed transaction */
+               i2c->high_speed_reg = I2C_TIME_CLR_VALUE;
+       }
+
+       return 0;
+}
+
+static int mtk_i2c_do_transfer(struct mtk_i2c *i2c, struct i2c_msg *msgs)
+{
+       u16 addr_reg;
+       u16 control_reg;
+       dma_addr_t rpaddr = 0;
+       dma_addr_t wpaddr = 0;
+       int ret;
+
+       i2c->irq_stat = 0;
+
+       reinit_completion(&i2c->msg_complete);
+
+       control_reg = readw(i2c->base + OFFSET_CONTROL) &
+                       ~(I2C_CONTROL_DIR_CHANGE | I2C_CONTROL_RS);
+       if (i2c->speed_hz > 400000)
+               control_reg |= I2C_CONTROL_RS;
+
+       if (i2c->op == I2C_MASTER_WRRD)
+               control_reg |= I2C_CONTROL_DIR_CHANGE | I2C_CONTROL_RS;
+
+       writew(control_reg, i2c->base + OFFSET_CONTROL);
+
+       /* set start condition */
+       if (i2c->speed_hz <= 100000)
+               writew(I2C_ST_START_CON, i2c->base + OFFSET_EXT_CONF);
+       else
+               writew(I2C_FS_START_CON, i2c->base + OFFSET_EXT_CONF);
+
+       addr_reg = msgs->addr << 1;
+       if (i2c->op == I2C_MASTER_RD)
+               addr_reg |= 0x1;
+
+       writew(addr_reg, i2c->base + OFFSET_SLAVE_ADDR);
+
+       /* Clear interrupt status */
+       writew(I2C_HS_NACKERR | I2C_ACKERR | I2C_TRANSAC_COMP,
+              i2c->base + OFFSET_INTR_STAT);
+       writew(I2C_FIFO_ADDR_CLR, i2c->base + OFFSET_FIFO_ADDR_CLR);
+
+       /* Enable interrupt */
+       writew(I2C_HS_NACKERR | I2C_ACKERR | I2C_TRANSAC_COMP,
+              i2c->base + OFFSET_INTR_MASK);
+
+       /* Set transfer and transaction len */
+       if (i2c->op == I2C_MASTER_WRRD) {
+               writew(msgs->len | ((msgs + 1)->len) << 8,
+                      i2c->base + OFFSET_TRANSFER_LEN);
+               writew(I2C_WRRD_TRANAC_VALUE, i2c->base + OFFSET_TRANSAC_LEN);
+       } else {
+               writew(msgs->len, i2c->base + OFFSET_TRANSFER_LEN);
+               writew(I2C_RD_TRANAC_VALUE, i2c->base + OFFSET_TRANSAC_LEN);
+       }
+
+       /* Prepare buffer data to start transfer */
+       if (i2c->op == I2C_MASTER_RD) {
+               writel(I2C_DMA_INT_FLAG_NONE, i2c->pdmabase + OFFSET_INT_FLAG);
+               writel(I2C_DMA_CON_RX, i2c->pdmabase + OFFSET_CON);
+               rpaddr = dma_map_single(i2c->dev, msgs->buf,
+                                       msgs->len, DMA_FROM_DEVICE);
+               if (dma_mapping_error(i2c->dev, rpaddr))
+                       return -ENOMEM;
+               writel((u32)rpaddr, i2c->pdmabase + OFFSET_RX_MEM_ADDR);
+               writel(msgs->len, i2c->pdmabase + OFFSET_RX_LEN);
+       } else if (i2c->op == I2C_MASTER_WR) {
+               writel(I2C_DMA_INT_FLAG_NONE, i2c->pdmabase + OFFSET_INT_FLAG);
+               writel(I2C_DMA_CON_TX, i2c->pdmabase + OFFSET_CON);
+               wpaddr = dma_map_single(i2c->dev, msgs->buf,
+                                       msgs->len, DMA_TO_DEVICE);
+               if (dma_mapping_error(i2c->dev, wpaddr))
+                       return -ENOMEM;
+               writel((u32)wpaddr, i2c->pdmabase + OFFSET_TX_MEM_ADDR);
+               writel(msgs->len, i2c->pdmabase + OFFSET_TX_LEN);
+       } else {
+               writel(I2C_DMA_CLR_FLAG, i2c->pdmabase + OFFSET_INT_FLAG);
+               writel(I2C_DMA_CLR_FLAG, i2c->pdmabase + OFFSET_CON);
+               wpaddr = dma_map_single(i2c->dev, msgs->buf,
+                                       msgs->len, DMA_TO_DEVICE);
+               if (dma_mapping_error(i2c->dev, wpaddr))
+                       return -ENOMEM;
+               rpaddr = dma_map_single(i2c->dev, (msgs + 1)->buf,
+                                       (msgs + 1)->len,
+                                       DMA_FROM_DEVICE);
+               if (dma_mapping_error(i2c->dev, rpaddr)) {
+                       dma_unmap_single(i2c->dev, wpaddr,
+                                        msgs->len, DMA_TO_DEVICE);
+                       return -ENOMEM;
+               }
+               writel((u32)wpaddr, i2c->pdmabase + OFFSET_TX_MEM_ADDR);
+               writel((u32)rpaddr, i2c->pdmabase + OFFSET_RX_MEM_ADDR);
+               writel(msgs->len, i2c->pdmabase + OFFSET_TX_LEN);
+               writel((msgs + 1)->len, i2c->pdmabase + OFFSET_RX_LEN);
+       }
+
+       writel(I2C_DMA_START_EN, i2c->pdmabase + OFFSET_EN);
+       writew(I2C_TRANSAC_START, i2c->base + OFFSET_START);
+
+       ret = wait_for_completion_timeout(&i2c->msg_complete,
+                                         i2c->adap.timeout);
+
+       /* Clear interrupt mask */
+       writew(~(I2C_HS_NACKERR | I2C_ACKERR |
+              I2C_TRANSAC_COMP), i2c->base + OFFSET_INTR_MASK);
+
+       if (i2c->op == I2C_MASTER_WR) {
+               dma_unmap_single(i2c->dev, wpaddr,
+                                msgs->len, DMA_TO_DEVICE);
+       } else if (i2c->op == I2C_MASTER_RD) {
+               dma_unmap_single(i2c->dev, rpaddr,
+                                msgs->len, DMA_FROM_DEVICE);
+       } else {
+               dma_unmap_single(i2c->dev, wpaddr, msgs->len,
+                                DMA_TO_DEVICE);
+               dma_unmap_single(i2c->dev, rpaddr, (msgs + 1)->len,
+                                DMA_FROM_DEVICE);
+       }
+
+       if (ret == 0) {
+               dev_dbg(i2c->dev, "addr: %x, transfer timeout\n", msgs->addr);
+               mtk_i2c_init_hw(i2c);
+               return -ETIMEDOUT;
+       }
+
+       completion_done(&i2c->msg_complete);
+
+       if (i2c->irq_stat & (I2C_HS_NACKERR | I2C_ACKERR)) {
+               dev_dbg(i2c->dev, "addr: %x, transfer ACK error\n", msgs->addr);
+               mtk_i2c_init_hw(i2c);
+               return -ENXIO;
+       }
+
+       return 0;
+}
+
+static int mtk_i2c_transfer(struct i2c_adapter *adap,
+                           struct i2c_msg msgs[], int num)
+{
+       int ret;
+       int left_num = num;
+       struct mtk_i2c *i2c = i2c_get_adapdata(adap);
+
+       ret = mtk_i2c_clock_enable(i2c);
+       if (ret)
+               return ret;
+
+       if (!msgs->buf) {
+               dev_dbg(i2c->dev, "data buffer is NULL.\n");
+               ret = -EINVAL;
+               goto err_exit;
+       }
+
+       if (msgs->flags & I2C_M_RD)
+               i2c->op = I2C_MASTER_RD;
+       else
+               i2c->op = I2C_MASTER_WR;
+
+       if (num > 1) {
+               /* combined two messages into one transaction */
+               i2c->op = I2C_MASTER_WRRD;
+               left_num--;
+       }
+
+       /* always use DMA mode. */
+       ret = mtk_i2c_do_transfer(i2c, msgs);
+       if (ret < 0)
+               goto err_exit;
+
+       /* the return value is number of executed messages */
+       ret = num;
+
+err_exit:
+       mtk_i2c_clock_disable(i2c);
+       return ret;
+}
+
+static irqreturn_t mtk_i2c_irq(int irqno, void *dev_id)
+{
+       struct mtk_i2c *i2c = dev_id;
+
+       i2c->irq_stat = readw(i2c->base + OFFSET_INTR_STAT);
+       writew(I2C_HS_NACKERR | I2C_ACKERR
+               | I2C_TRANSAC_COMP, i2c->base + OFFSET_INTR_STAT);
+
+       complete(&i2c->msg_complete);
+
+       return IRQ_HANDLED;
+}
+
+static u32 mtk_i2c_functionality(struct i2c_adapter *adap)
+{
+       return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
+}
+
+static const struct i2c_algorithm mtk_i2c_algorithm = {
+       .master_xfer = mtk_i2c_transfer,
+       .functionality = mtk_i2c_functionality,
+};
+
+static int mtk_i2c_parse_dt(struct device_node *np, struct mtk_i2c *i2c,
+                           unsigned int *clk_src_div)
+{
+       int ret;
+
+       ret = of_property_read_u32(np, "clock-frequency", &i2c->speed_hz);
+       if (ret < 0)
+               i2c->speed_hz = I2C_DEFAULT_SPEED;
+
+       ret = of_property_read_u32(np, "clock-div", clk_src_div);
+       if (ret < 0)
+               return ret;
+
+       if (*clk_src_div == 0)
+               return -EINVAL;
+
+       i2c->have_pmic = of_property_read_bool(np, "mediatek,have-pmic");
+       i2c->use_push_pull =
+               of_property_read_bool(np, "mediatek,use-push-pull");
+
+       return 0;
+}
+
+static int mtk_i2c_probe(struct platform_device *pdev)
+{
+       const struct of_device_id *of_id;
+       int ret = 0;
+       struct mtk_i2c *i2c;
+       struct clk *clk;
+       unsigned int clk_src_div;
+       struct resource *res;
+       int irq;
+
+       i2c = devm_kzalloc(&pdev->dev, sizeof(*i2c), GFP_KERNEL);
+       if (!i2c)
+               return -ENOMEM;
+
+       ret = mtk_i2c_parse_dt(pdev->dev.of_node, i2c, &clk_src_div);
+       if (ret)
+               return -EINVAL;
+
+       res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+       i2c->base = devm_ioremap_resource(&pdev->dev, res);
+       if (IS_ERR(i2c->base))
+               return PTR_ERR(i2c->base);
+
+       res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
+       i2c->pdmabase = devm_ioremap_resource(&pdev->dev, res);
+       if (IS_ERR(i2c->pdmabase))
+               return PTR_ERR(i2c->pdmabase);
+
+       irq = platform_get_irq(pdev, 0);
+       if (irq <= 0)
+               return irq;
+
+       init_completion(&i2c->msg_complete);
+
+       of_id = of_match_node(mtk_i2c_of_match, pdev->dev.of_node);
+       if (!of_id)
+               return -EINVAL;
+
+       i2c->dev_comp = of_id->data;
+       i2c->adap.dev.of_node = pdev->dev.of_node;
+       i2c->dev = &pdev->dev;
+       i2c->adap.dev.parent = &pdev->dev;
+       i2c->adap.owner = THIS_MODULE;
+       i2c->adap.algo = &mtk_i2c_algorithm;
+       i2c->adap.quirks = i2c->dev_comp->quirks;
+       i2c->adap.timeout = 2 * HZ;
+       i2c->adap.retries = 1;
+
+       if (i2c->have_pmic && !i2c->dev_comp->pmic_i2c)
+               return -EINVAL;
+
+       i2c->clk_main = devm_clk_get(&pdev->dev, "main");
+       if (IS_ERR(i2c->clk_main)) {
+               dev_err(&pdev->dev, "cannot get main clock\n");
+               return PTR_ERR(i2c->clk_main);
+       }
+
+       i2c->clk_dma = devm_clk_get(&pdev->dev, "dma");
+       if (IS_ERR(i2c->clk_dma)) {
+               dev_err(&pdev->dev, "cannot get dma clock\n");
+               return PTR_ERR(i2c->clk_dma);
+       }
+
+       clk = i2c->clk_main;
+       if (i2c->have_pmic) {
+               i2c->clk_pmic = devm_clk_get(&pdev->dev, "pmic");
+               if (IS_ERR(i2c->clk_pmic)) {
+                       dev_err(&pdev->dev, "cannot get pmic clock\n");
+                       return PTR_ERR(i2c->clk_pmic);
+               }
+               clk = i2c->clk_pmic;
+       }
+
+       strlcpy(i2c->adap.name, I2C_DRV_NAME, sizeof(i2c->adap.name));
+
+       ret = mtk_i2c_set_speed(i2c, clk_get_rate(clk), clk_src_div);
+       if (ret) {
+               dev_err(&pdev->dev, "Failed to set the speed.\n");
+               return -EINVAL;
+       }
+
+       ret = mtk_i2c_clock_enable(i2c);
+       if (ret) {
+               dev_err(&pdev->dev, "clock enable failed!\n");
+               return ret;
+       }
+       mtk_i2c_init_hw(i2c);
+       mtk_i2c_clock_disable(i2c);
+
+       ret = devm_request_irq(&pdev->dev, irq, mtk_i2c_irq,
+                              IRQF_TRIGGER_NONE, I2C_DRV_NAME, i2c);
+       if (ret < 0) {
+               dev_err(&pdev->dev,
+                       "Request I2C IRQ %d fail\n", irq);
+               return ret;
+       }
+
+       i2c_set_adapdata(&i2c->adap, i2c);
+       ret = i2c_add_adapter(&i2c->adap);
+       if (ret) {
+               dev_err(&pdev->dev, "Failed to add i2c bus to i2c core\n");
+               return ret;
+       }
+
+       platform_set_drvdata(pdev, i2c);
+
+       return 0;
+}
+
+static int mtk_i2c_remove(struct platform_device *pdev)
+{
+       struct mtk_i2c *i2c = platform_get_drvdata(pdev);
+
+       i2c_del_adapter(&i2c->adap);
+
+       return 0;
+}
+
+static struct platform_driver mtk_i2c_driver = {
+       .probe = mtk_i2c_probe,
+       .remove = mtk_i2c_remove,
+       .driver = {
+               .name = I2C_DRV_NAME,
+               .of_match_table = of_match_ptr(mtk_i2c_of_match),
+       },
+};
+
+module_platform_driver(mtk_i2c_driver);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("MediaTek I2C Bus Driver");
+MODULE_AUTHOR("Xudong Chen <xudong.chen@mediatek.com>");