[PATCH v2 0/3] ARM: mediatek: Add driver for Mediatek I2C controller

[PATCH v2 0/3] ARM: mediatek: Add driver for Mediatek I2C controller

[Xudong Chen]

This series is the second version of Mediatek SoCs I2C controller common
bus driver.
Compared to the first version,
1. Add comment for feature have-pmic in dt-bindings file i2c-mt6577.txt.
2. Add notes for I2C4/5/6 in mt8135.dtsi.
3. Add check compatible for the feature have-pmic in i2c-mt65xx.c, if set
have-pmic for the compatible mt6577 the driver will return error.

Because the clock driver for mediatek SoC is not ready yet(still work in
progress), so I delete the related clock code in dtsi file for now.

This driver is based on 3.18-rc1 & Hongzhou's gpio patch.

MTK I2C HW has some limitation.
1. If the i2c_msg number is more than one, STOP will be issued instead of
RS(Repeat Start) between each message.
Such as: "START + ADDR + DATA_n + STOP + START + ADDR + DATA_n + STOP ..."

2. Mediatek I2C controller support WRRD(write then read) mode, in WRRD
mode the Repeat Start will be issued between 2 messages.
In this driver if 2 messages is first write then read, the driver will
combine 2 messages using Write-Read mode so the RS will be issued between
the 2 messages.
Ex: W/R/R, driver will combine first W/R and then R.
The data series will be:
"START + WriteADDR + DATA + RS + ReadADDR + DATA + STOP + START + ReadADDR +
DATA + STOP".

3. Due to HW limitation, in this version the max transfer data length is 255
in one message. If want to transfer more than 255 bytes, HW needs the SW
driver to split the data. Take 600 bytes for example, the data need to be
divided into 3 parts 255 + 255 + 90. The data series will be:
"START + ADDR + DATA_255 + RS + ADDR + DATA_255 + RS + ADDR +  DATA_90 + STOP"
instead of "START + ADDR + DATA_900 + STOP".
We haven't implement this yet, we will do this in the separate patch.

MT8135 and MT6589 can control I2C pins on PMIC(MT6397) by setting the i2c
registers in MT8135 side. In this case, driver should set OFFSET_PATH_DIR
bit first, the operation on other registers are still the same.
For now MT6589/MT8135 support this, MT6577/MT6595/MT8127 do not support.
For example, If want to use I2C4/5/6 pins on MT8135 just need to enable
the pinmux, else if want to use I2C pins on PMIC(MT6397) just need to add
"mediatek,have-pmic" property in the .dts file of each platform.

Xudong Chen (3):
  dt-bindings: Add I2C bindings for mt65xx/mt81xx.
  ARM: mediatek: Add I2C node for mt8135 and mt8127
  I2C: mediatek: Add driver for MediaTek I2C controller

 .../devicetree/bindings/i2c/i2c-mt6577.txt         |  39 ++
 arch/arm/boot/dts/mt8127.dtsi                      |  27 +
 arch/arm/boot/dts/mt8135.dtsi                      |  90 +++
 drivers/i2c/busses/Kconfig                         |   9 +
 drivers/i2c/busses/Makefile                        |   1 +
 drivers/i2c/busses/i2c-mt65xx.c                    | 742 +++++++++++++++++++++
 6 files changed, 908 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/i2c/i2c-mt6577.txt
 create mode 100644 drivers/i2c/busses/i2c-mt65xx.c

--
1.8.1.1.dirty

[PATCH v2 1/3] dt-bindings: Add I2C bindings for mt65xx/mt81xx.

[Xudong Chen]

Add devicetree bindings for Mediatek Soc I2C driver.

Signed-off-by: Xudong Chen <xudong.chen@mediatek.com>
---
 .../devicetree/bindings/i2c/i2c-mt6577.txt         | 39 ++++++++++++++++++++++
 1 file changed, 39 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/i2c/i2c-mt6577.txt

diff --git a/Documentation/devicetree/bindings/i2c/i2c-mt6577.txt b/Documentation/devicetree/bindings/i2c/i2c-mt6577.txt
new file mode 100644
index 0000000..733e65e
--- /dev/null
+++ b/Documentation/devicetree/bindings/i2c/i2c-mt6577.txt
@@ -0,0 +1,39 @@
+* 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.
+  - 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: clock name used in i2c driver probe
+
+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,have-dcm: platform has DCM(hardware digital clock manager) property.
+  - mediatek,use-push-pull: IO 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 = <100000>;
+			mediatek,have-pmic;
+			clock-div = <16>;
+			clocks = <&i2c0_ck>, <&ap_dma_ck>;
+			clock-names = "main", "dma";
+	};
+
-- 
1.8.1.1.dirty

[PATCH v2 2/3] ARM: mediatek: Add I2C node for mt8135 and mt8127

[Xudong Chen]

Add I2C node to mt8135.dtsi and mt8127.dtsi

Signed-off-by: Xudong Chen <xudong.chen@mediatek.com>
---
 arch/arm/boot/dts/mt8127.dtsi | 27 +++++++++++++
 arch/arm/boot/dts/mt8135.dtsi | 90 +++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 117 insertions(+)

diff --git a/arch/arm/boot/dts/mt8127.dtsi b/arch/arm/boot/dts/mt8127.dtsi
index 25c9f69..60d7685e 100644
--- a/arch/arm/boot/dts/mt8127.dtsi
+++ b/arch/arm/boot/dts/mt8127.dtsi
@@ -89,5 +89,32 @@
 			      <0 0x10214000 0 0x2000>,
 			      <0 0x10216000 0 0x2000>;
 		};
+
+		i2c0: i2c@11007000 {
+			compatible = "mediatek,mt8127-i2c",
+				"mediatek,mt6577-i2c";
+			reg = <0 0x11007000 0 0x70>,
+				<0 0x11000200 0 0x80>;
+			interrupts = <GIC_SPI 44 IRQ_TYPE_LEVEL_LOW>;
+			mediatek,have-dcm;
+		};
+
+		i2c1: i2c@11008000 {
+			compatible = "mediatek,mt8127-i2c",
+				"mediatek,mt6577-i2c";
+			reg = <0 0x11008000 0 0x70>,
+				<0 0x11000280 0 0x80>;
+			interrupts = <GIC_SPI 45 IRQ_TYPE_LEVEL_LOW>;
+			mediatek,have-dcm;
+		};
+
+		i2c2: i2c@11009000 {
+			compatible = "mediatek,mt8127-i2c",
+				"mediatek,mt6577-i2c";
+			reg = <0 0x11009000 0 0x70>,
+				<0 0x11000300 0 0x80>;
+			interrupts = <GIC_SPI 46 IRQ_TYPE_LEVEL_LOW>;
+			mediatek,have-dcm;
+		};
 	};
 };
diff --git a/arch/arm/boot/dts/mt8135.dtsi b/arch/arm/boot/dts/mt8135.dtsi
index 221ce09..cb32350 100644
--- a/arch/arm/boot/dts/mt8135.dtsi
+++ b/arch/arm/boot/dts/mt8135.dtsi
@@ -119,7 +119,97 @@
 			      <0 0x1020C000 0 0x1000>;
 			gpio-controller;
 			#gpio-cells = <2>;
+
+			i2c0_pins_a: i2c0@0 {
+				mediatek,pins = <MT8135_PIN_100_SDA0__FUNC_SDA0 &pcfg_pull_none>,
+						<MT8135_PIN_101_SCL0__FUNC_SCL0 &pcfg_pull_none>;
+			};
+
+			i2c1_pins_a: i2c1@0 {
+				mediatek,pins = <MT8135_PIN_195_SDA1__FUNC_SDA1 &pcfg_pull_none>,
+						<MT8135_PIN_196_SCL1__FUNC_SCL1 &pcfg_pull_none>;
+			};
+
+			i2c2_pins_a: i2c2@0 {
+				mediatek,pins = <MT8135_PIN_193_SDA2__FUNC_SDA2 &pcfg_pull_none>,
+						<MT8135_PIN_194_SCL2__FUNC_SCL2 &pcfg_pull_none>;
+			};
+
+			i2c3_pins_a: i2c3@0 {
+				mediatek,pins = <MT8135_PIN_35_SCL3__FUNC_SCL3 &pcfg_pull_none>,
+						<MT8135_PIN_36_SDA3__FUNC_SDA3 &pcfg_pull_none>;
+			};
+
+			i2c4_pins_a: i2c4@0 {
+				mediatek,pins = <MT8135_PIN_87_MSDC1_DAT2__FUNC_SCL4 &pcfg_pull_none>,
+						<MT8135_PIN_88_MSDC1_DAT3__FUNC_SDA4 &pcfg_pull_none>;
+			};
+
+			i2c5_pins_a: i2c5@0 {
+				mediatek,pins = <MT8135_PIN_63_MSDC1_INSI__FUNC_SCL5 &pcfg_pull_none>,
+						<MT8135_PIN_64_MSDC1_SDWPI__FUNC_SDA5 &pcfg_pull_none>;
+			};
+
+			i2c6_pins_a: i2c6@0 {
+				mediatek,pins = <MT8135_PIN_197_MSDC3_DAT2__FUNC_SCL6 &pcfg_pull_none>,
+						<MT8135_PIN_198_MSDC3_DAT3__FUNC_SDA6 &pcfg_pull_none>;
+			};
 		};
 
+		i2c0: i2c@1100d000 {
+			compatible = "mediatek,mt8135-i2c",
+				"mediatek,mt6589-i2c";
+			reg = <0 0x1100d000 0 0x70>,
+				<0 0x11000300 0 0x80>;
+			interrupts = <GIC_SPI 44 IRQ_TYPE_LEVEL_LOW>;
+		};
+
+		i2c1: i2c@1100e000 {
+			compatible = "mediatek,mt8135-i2c",
+				"mediatek,mt6589-i2c";
+			reg = <0 0x1100e000 0 0x70>,
+				<0 0x11000380 0 0x80>;
+			interrupts = <GIC_SPI 45 IRQ_TYPE_LEVEL_LOW>;
+		};
+
+		i2c2: i2c@1100f000 {
+			compatible = "mediatek,mt8135-i2c",
+				"mediatek,mt6589-i2c";
+			reg = <0 0x1100f000 0 0x70>,
+				<0 0x11000400 0 0x80>;
+			interrupts = <GIC_SPI 46 IRQ_TYPE_LEVEL_LOW>;
+		};
+
+		i2c3: i2c@11010000 {
+			compatible = "mediatek,mt8135-i2c",
+				"mediatek,mt6589-i2c";
+			reg = <0 0x11010000 0 0x70>,
+				<0 0x11000480 0 0x80>;
+			interrupts = <GIC_SPI 47 IRQ_TYPE_LEVEL_LOW>;
+		};
+
+		i2c4: i2c@11011000 {
+			compatible = "mediatek,mt8135-i2c",
+				"mediatek,mt6589-i2c";
+			reg = <0 0x11011000 0 0x70>,
+				<0 0x11000500 0 0x80>;
+			interrupts = <GIC_SPI 48 IRQ_TYPE_LEVEL_LOW>;
+		};
+
+		i2c5: i2c@11012000 {
+			compatible = "mediatek,mt8135-i2c",
+				"mediatek,mt6589-i2c";
+			reg = <0 0x11012000 0 0x70>,
+				<0 0x11000580 0 0x80>;
+			interrupts = <GIC_SPI 49 IRQ_TYPE_LEVEL_LOW>;
+		};
+
+		i2c6: i2c@11013000 {
+			compatible = "mediatek,mt8135-i2c",
+				"mediatek,mt6589-i2c";
+			reg = <0 0x11013000 0 0x70>,
+				<0 0x11000600 0 0x80>;
+			interrupts = <GIC_SPI 50 IRQ_TYPE_LEVEL_LOW>;
+		};
 	};
 };
-- 
1.8.1.1.dirty

[PATCH v2 3/3] I2C: mediatek: Add driver for MediaTek I2C controller

[Xudong Chen]

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>
---
 drivers/i2c/busses/Kconfig      |   9 +
 drivers/i2c/busses/Makefile     |   1 +
 drivers/i2c/busses/i2c-mt65xx.c | 742 ++++++++++++++++++++++++++++++++++++++++
 3 files changed, 752 insertions(+)
 create mode 100644 drivers/i2c/busses/i2c-mt65xx.c

diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
index 917c358..0d7d0a4 100644
--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -564,6 +564,15 @@ 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
+	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
diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
index 78d56c5..7a9f0f3 100644
--- a/drivers/i2c/busses/Makefile
+++ b/drivers/i2c/busses/Makefile
@@ -54,6 +54,7 @@ obj-$(CONFIG_I2C_IMX)		+= i2c-imx.o
 obj-$(CONFIG_I2C_IOP3XX)	+= i2c-iop3xx.o
 obj-$(CONFIG_I2C_KEMPLD)	+= i2c-kempld.o
 obj-$(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
index 0000000..4a0f4b0
--- /dev/null
+++ b/drivers/i2c/busses/i2c-mt65xx.c
@@ -0,0 +1,742 @@
+/*
+ * 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/kernel.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/i2c.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/sched.h>
+#include <linux/delay.h>
+#include <linux/errno.h>
+#include <linux/err.h>
+#include <linux/device.h>
+#include <linux/platform_device.h>
+#include <linux/wait.h>
+#include <linux/mm.h>
+#include <linux/dma-mapping.h>
+#include <linux/scatterlist.h>
+#include <linux/io.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/clk.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_TIMING_STEP_DIV_MASK	(0x3f << 0)
+#define I2C_TIMING_SAMPLE_COUNT_MASK	(0x7 << 0)
+#define I2C_TIMING_SAMPLE_DIV_MASK	(0x7 << 8)
+#define I2C_TIMING_DATA_READ_MASK	(0x7 << 12)
+#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_DEFAUT_SPEED		100000	/* hz */
+#define MAX_FS_MODE_SPEED		400000
+#define MAX_HS_MODE_SPEED		3400000
+#define MAX_DMA_TRANS_SIZE		255
+#define MAX_WRRD_TRANS_SIZE		32
+#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 COMPAT_MT6577			(0x1 << 0)
+#define COMPAT_MT6589			(0x1 << 1)
+
+#define I2C_DRV_NAME		"mt-i2c"
+
+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 {
+	FS_MODE,
+	HS_MODE,
+};
+
+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_data {
+	unsigned int clk_frequency;	/* bus speed in Hz */
+	unsigned int flags;
+	unsigned int clk_src_div;
+};
+
+struct i2c_dma_buf {
+	u8 *vaddr;
+	dma_addr_t paddr;
+};
+
+struct mtk_i2c {
+	struct i2c_adapter adap;	/* i2c host adapter */
+	struct device *dev;
+	wait_queue_head_t wait;		/* i2c transfer wait queue */
+	/* set in i2c probe */
+	void __iomem *base;		/* i2c base addr */
+	void __iomem *pdmabase;		/* dma base address*/
+	int irqnr;			/* i2c interrupt number */
+	struct i2c_dma_buf dma_buf;	/* memory alloc for DMA mode */
+	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 form PMIC */
+	bool have_dcm;			/* HW DCM function */
+	bool use_push_pull;		/* IO config push-pull mode */
+	/* set when doing the transfer */
+	u16 irq_stat;			/* interrupt status */
+	unsigned int speed_hz;		/* The speed in transfer */
+	bool trans_stop;		/* i2c transfer stop */
+	enum mtk_trans_op op;
+	u16 msg_len;
+	u8 *msg_buf;			/* pointer to msg data */
+	u16 msg_aux_len;		/* WRRD mode to set AUX_LEN register*/
+	u16 addr;	/* 7bit slave address, without read/write bit */
+	u16 timing_reg;
+	u16 high_speed_reg;
+};
+
+static const struct of_device_id mtk_i2c_of_match[] = {
+	{ .compatible = "mediatek,mt6577-i2c", .data = (void *)COMPAT_MT6577 },
+	{ .compatible = "mediatek,mt6589-i2c", .data = (void *)COMPAT_MT6589 },
+	{},
+};
+MODULE_DEVICE_TABLE(of, mtk_i2c_match);
+
+static inline void i2c_writew(u16 value, struct mtk_i2c *i2c, u8 offset)
+{
+	writew(value, i2c->base + offset);
+}
+
+static inline u16 i2c_readw(struct mtk_i2c *i2c, u8 offset)
+{
+	return readw(i2c->base + offset);
+}
+
+static inline void i2c_writel_dma(u32 value, struct mtk_i2c *i2c, u8 offset)
+{
+	writel(value, i2c->pdmabase + offset);
+}
+
+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 free_i2c_dma_bufs(struct mtk_i2c *i2c)
+{
+	dma_free_coherent(i2c->adap.dev.parent, PAGE_SIZE,
+		i2c->dma_buf.vaddr, i2c->dma_buf.paddr);
+}
+
+static inline void mtk_i2c_init_hw(struct mtk_i2c *i2c)
+{
+	i2c_writew(I2C_SOFT_RST, i2c, OFFSET_SOFTRESET);
+	/* Set ioconfig */
+	if (i2c->use_push_pull)
+		i2c_writew(I2C_IO_CONFIG_PUSH_PULL, i2c, OFFSET_IO_CONFIG);
+	else
+		i2c_writew(I2C_IO_CONFIG_OPEN_DRAIN, i2c, OFFSET_IO_CONFIG);
+
+	if (i2c->have_dcm)
+		i2c_writew(I2C_DCM_DISABLE, i2c, OFFSET_DCM_EN);
+
+	i2c_writew(i2c->timing_reg, i2c, OFFSET_TIMING);
+	i2c_writew(i2c->high_speed_reg, i2c, OFFSET_HS);
+}
+
+/* calculate i2c port speed */
+static int i2c_set_speed(struct mtk_i2c *i2c, unsigned int clk_src_in_hz)
+{
+	int mode;
+	unsigned int khz;
+	unsigned int step_cnt;
+	unsigned int sample_cnt;
+	unsigned int sclk;
+	unsigned int hclk;
+	unsigned int max_step_cnt;
+	unsigned int sample_div = MAX_SAMPLE_CNT_DIV;
+	unsigned int step_div;
+	unsigned int min_div;
+	unsigned int best_mul;
+	unsigned int cnt_mul;
+
+	if (i2c->speed_hz > MAX_HS_MODE_SPEED) {
+		return -EINVAL;
+	} else if (i2c->speed_hz > MAX_FS_MODE_SPEED) {
+		mode = HS_MODE;
+		max_step_cnt = MAX_HS_STEP_CNT_DIV;
+	} else {
+		mode = FS_MODE;
+		max_step_cnt = MAX_STEP_CNT_DIV;
+	}
+
+	step_div = max_step_cnt;
+	/* Find the best combination */
+	khz = i2c->speed_hz / 1000;
+	hclk = clk_src_in_hz / 1000;
+	min_div = ((hclk >> 1) + khz - 1) / khz;
+	best_mul = MAX_SAMPLE_CNT_DIV * max_step_cnt;
+
+	for (sample_cnt = 1; sample_cnt <= MAX_SAMPLE_CNT_DIV; sample_cnt++) {
+		step_cnt = (min_div + sample_cnt - 1) / sample_cnt;
+		cnt_mul = step_cnt * sample_cnt;
+		if (step_cnt > max_step_cnt)
+			continue;
+
+		if (cnt_mul < best_mul) {
+			best_mul = cnt_mul;
+			sample_div = sample_cnt;
+			step_div = step_cnt;
+			if (best_mul == min_div)
+				break;
+		}
+	}
+
+	sample_cnt = sample_div;
+	step_cnt = step_div;
+	sclk = hclk / (2 * sample_cnt * step_cnt);
+	if (sclk > khz) {
+		dev_dbg(i2c->dev, "%s mode: unsupported speed (%ldkhz)\n",
+			(mode == HS_MODE) ? "HS" : "ST/FT", (long int)khz);
+		return -ENOTSUPP;
+	}
+
+	step_cnt--;
+	sample_cnt--;
+
+	if (mode == HS_MODE) {
+		/* Set the hign speed mode register */
+		i2c->timing_reg = I2C_FS_TIME_INIT_VALUE;
+		i2c->high_speed_reg = I2C_TIME_DEFAULT_VALUE |
+			(sample_cnt & I2C_TIMING_SAMPLE_COUNT_MASK) << 12 |
+			(step_cnt & I2C_TIMING_SAMPLE_COUNT_MASK) << 8;
+	} else {
+		i2c->timing_reg =
+			(sample_cnt & I2C_TIMING_SAMPLE_COUNT_MASK) << 8 |
+			(step_cnt & I2C_TIMING_STEP_DIV_MASK) << 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)
+{
+	u16 addr_reg;
+	u16 control_reg;
+	int tmo = i2c->adap.timeout;
+
+	i2c->trans_stop = false;
+	i2c->irq_stat = 0;
+
+	/* If use i2c pin from PMIC mt6397 side, need set PATH_DIR first */
+	if (i2c->have_pmic)
+		i2c_writew(I2C_CONTROL_WRAPPER, i2c, OFFSET_PATH_DIR);
+
+	control_reg = I2C_CONTROL_ACKERR_DET_EN |
+		I2C_CONTROL_CLK_EXT_EN | I2C_CONTROL_DMA_EN;
+	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;
+	i2c_writew(control_reg, i2c, OFFSET_CONTROL);
+
+	/* set start condition */
+	if (i2c->speed_hz <= 100000)
+		i2c_writew(I2C_ST_START_CON, i2c, OFFSET_EXT_CONF);
+	else
+		i2c_writew(I2C_FS_START_CON, i2c, OFFSET_EXT_CONF);
+
+	if (~control_reg & I2C_CONTROL_RS)
+		i2c_writew(I2C_DELAY_LEN, i2c, OFFSET_DELAY_LEN);
+
+	addr_reg = i2c->addr << 1;
+	if (i2c->op == I2C_MASTER_RD)
+		addr_reg |= 0x1;
+	i2c_writew(addr_reg, i2c, OFFSET_SLAVE_ADDR);
+
+	/* Clear interrupt status */
+	i2c_writew(I2C_HS_NACKERR | I2C_ACKERR | I2C_TRANSAC_COMP,
+		i2c, OFFSET_INTR_STAT);
+	i2c_writew(I2C_FIFO_ADDR_CLR, i2c, OFFSET_FIFO_ADDR_CLR);
+
+	/* Enable interrupt */
+	i2c_writew(I2C_HS_NACKERR | I2C_ACKERR | I2C_TRANSAC_COMP,
+		i2c, OFFSET_INTR_MASK);
+
+	/* Set transfer and transaction len */
+	if (i2c->op == I2C_MASTER_WRRD) {
+		i2c_writew(i2c->msg_len | (i2c->msg_aux_len) << 8,
+			i2c, OFFSET_TRANSFER_LEN);
+		i2c_writew(I2C_WRRD_TRANAC_VALUE, i2c, OFFSET_TRANSAC_LEN);
+	} else {
+		i2c_writew(i2c->msg_len, i2c, OFFSET_TRANSFER_LEN);
+		i2c_writew(I2C_RD_TRANAC_VALUE, i2c, OFFSET_TRANSAC_LEN);
+	}
+
+	/* Prepare buffer data to start transfer */
+	if (i2c->op == I2C_MASTER_RD) {
+		i2c_writel_dma(I2C_DMA_INT_FLAG_NONE, i2c, OFFSET_INT_FLAG);
+		i2c_writel_dma(I2C_DMA_CON_RX, i2c, OFFSET_CON);
+		i2c_writel_dma((u32)i2c->msg_buf, i2c, OFFSET_RX_MEM_ADDR);
+		i2c_writel_dma(i2c->msg_len, i2c, OFFSET_RX_LEN);
+	} else if (i2c->op == I2C_MASTER_WR) {
+		i2c_writel_dma(I2C_DMA_INT_FLAG_NONE, i2c, OFFSET_INT_FLAG);
+		i2c_writel_dma(I2C_DMA_CON_TX, i2c, OFFSET_CON);
+		i2c_writel_dma((u32)i2c->msg_buf, i2c, OFFSET_TX_MEM_ADDR);
+		i2c_writel_dma(i2c->msg_len, i2c, OFFSET_TX_LEN);
+	} else {
+		i2c_writel_dma(I2C_DMA_CLR_FLAG, i2c, OFFSET_INT_FLAG);
+		i2c_writel_dma(I2C_DMA_CLR_FLAG, i2c, OFFSET_CON);
+		i2c_writel_dma((u32)i2c->msg_buf, i2c, OFFSET_TX_MEM_ADDR);
+		i2c_writel_dma((u32)i2c->dma_buf.paddr, i2c,
+			OFFSET_RX_MEM_ADDR);
+		i2c_writel_dma(i2c->msg_len, i2c, OFFSET_TX_LEN);
+		i2c_writel_dma(i2c->msg_aux_len, i2c, OFFSET_RX_LEN);
+	}
+
+	/* flush before sending start */
+	mb();
+	i2c_writel_dma(I2C_DMA_START_EN, i2c, OFFSET_EN);
+	i2c_writew(I2C_TRANSAC_START, i2c, OFFSET_START);
+
+	tmo = wait_event_timeout(i2c->wait, i2c->trans_stop, tmo);
+	if (tmo == 0) {
+		dev_dbg(i2c->dev, "addr: %x, transfer timeout\n", i2c->addr);
+		mtk_i2c_init_hw(i2c);
+		return -ETIMEDOUT;
+	}
+
+	if (i2c->irq_stat & (I2C_HS_NACKERR | I2C_ACKERR)) {
+		dev_dbg(i2c->dev, "addr: %x, transfer ACK error\n", i2c->addr);
+		mtk_i2c_init_hw(i2c);
+		return -EREMOTEIO;
+	}
+
+	dev_dbg(i2c->dev, "i2c transfer done.\n");
+
+	return 0;
+}
+
+static inline void mtk_i2c_copy_to_dma(struct mtk_i2c *i2c, struct i2c_msg *msg)
+{
+	/* if the operate is write, need to copy the data to DMA memory */
+	if (!(msg->flags & I2C_M_RD))
+		memcpy(i2c->dma_buf.vaddr, msg->buf, msg->len);
+}
+
+static inline void mtk_i2c_copy_from_dma(struct mtk_i2c *i2c,
+	struct i2c_msg *msg)
+{
+	/* if the operate is read, need to copy the data from DMA memory */
+	if (msg->flags & I2C_M_RD)
+		memcpy(msg->buf, i2c->dma_buf.vaddr, msg->len);
+}
+
+/*
+ * In MTK platform the STOP will be issued after each
+ * message was transferred which is not flow the clarify
+ * for i2c_transfer(), several I2C devices tolerate the STOP,
+ * but some device need Repeat-Start and do not compatible with STOP
+ * MTK platform has WRRD mode which can write then read with
+ * Repeat-Start between two message, so we combined two
+ * messages into one transaction.
+ * The max read length is 31
+ */
+static bool mtk_i2c_should_combine(struct i2c_msg *msg)
+{
+	struct i2c_msg *next_msg = msg + 1;
+
+	if ((next_msg->len < MAX_WRRD_TRANS_SIZE) &&
+			msg->addr == next_msg->addr &&
+			!(msg->flags & I2C_M_RD) &&
+			(next_msg->flags & I2C_M_RD) == I2C_M_RD) {
+		return true;
+	}
+
+	return false;
+}
+
+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;
+
+	while (left_num--) {
+		/* In MTK platform the max transfer number is 255 */
+		if (msgs->len > MAX_DMA_TRANS_SIZE) {
+			dev_dbg(i2c->dev,
+				" message data length is more than 255\n");
+			ret = -EINVAL;
+			goto err_exit;
+		}
+
+		if (msgs->addr == 0) {
+			dev_dbg(i2c->dev, " addr is invalid.\n");
+			ret = -EINVAL;
+			goto err_exit;
+		}
+
+		if (msgs->buf == NULL) {
+			dev_dbg(i2c->dev, " data buffer is NULL.\n");
+			ret = -EINVAL;
+			goto err_exit;
+		}
+
+		i2c->addr = msgs->addr;
+		i2c->msg_len = msgs->len;
+		i2c->msg_buf = msgs->buf;
+
+		if (msgs->flags & I2C_M_RD)
+			i2c->op = I2C_MASTER_RD;
+		else
+			i2c->op = I2C_MASTER_WR;
+
+		/* combined two messages into one transaction */
+		if (left_num >= 1 && mtk_i2c_should_combine(msgs)) {
+			i2c->msg_aux_len = (msgs + 1)->len;
+			i2c->op = I2C_MASTER_WRRD;
+			left_num--;
+		}
+
+		/*
+		 * always use DMA mode.
+		 * 1st when write need copy the data of message to dma memory
+		 * 2nd when read need copy the DMA data to the message buffer.
+		 * The length should be less than 255.
+		 */
+		mtk_i2c_copy_to_dma(i2c, msgs);
+		i2c->msg_buf = (u8 *)i2c->dma_buf.paddr;
+		ret = mtk_i2c_do_transfer(i2c);
+		if (ret < 0)
+			goto err_exit;
+
+		if (i2c->op == I2C_MASTER_WRRD)
+			mtk_i2c_copy_from_dma(i2c, msgs + 1);
+		else
+			mtk_i2c_copy_from_dma(i2c, msgs);
+
+		msgs++;
+
+		/* after combined two messages so we need ignore one */
+		if (left_num > 0 && i2c->op == I2C_MASTER_WRRD)
+			msgs++;
+	}
+	/* 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;
+
+	/* Clear interrupt mask */
+	i2c_writew(~(I2C_HS_NACKERR | I2C_ACKERR | I2C_TRANSAC_COMP),
+		i2c, OFFSET_INTR_MASK);
+
+	i2c->irq_stat = i2c_readw(i2c, OFFSET_INTR_STAT);
+	i2c_writew(I2C_HS_NACKERR | I2C_ACKERR | I2C_TRANSAC_COMP,
+		i2c, OFFSET_INTR_STAT);
+	i2c->trans_stop = true;
+	wake_up(&i2c->wait);
+
+	return IRQ_HANDLED;
+}
+
+static u32 mtk_i2c_functionality(struct i2c_adapter *adap)
+{
+	return I2C_FUNC_I2C | I2C_FUNC_10BIT_ADDR | I2C_FUNC_SMBUS_EMUL;
+}
+
+static const struct i2c_algorithm mtk_i2c_algorithm = {
+	.master_xfer = mtk_i2c_transfer,
+	.functionality = mtk_i2c_functionality,
+};
+
+static inline u32 mtk_get_device_prop(struct platform_device *pdev)
+{
+	const struct of_device_id *match;
+
+	match = of_match_node(mtk_i2c_of_match, pdev->dev.of_node);
+	return (u32)match->data;
+}
+
+static int mtk_i2c_parse_dt(struct device_node *np, struct mtk_i2c *i2c,
+	unsigned int *clk_src_div)
+{
+	i2c->speed_hz = I2C_DEFAUT_SPEED;
+	of_property_read_u32(np, "clock-frequency", &i2c->speed_hz);
+	of_property_read_u32(np, "clock-div", clk_src_div);
+	if (*clk_src_div == 0)
+		return -EINVAL;
+
+	i2c->have_pmic = of_property_read_bool(np, "mediatek,have-pmic");
+	i2c->have_dcm = of_property_read_bool(np, "mediatek,have-dcm");
+	i2c->use_push_pull =
+		of_property_read_bool(np, "mediatek,use-push-pull");
+
+	return 0;
+}
+
+static int mtk_i2c_probe(struct platform_device *pdev)
+{
+	int ret = 0;
+	struct mtk_i2c *i2c;
+	unsigned int clk_src_in_hz;
+	unsigned int clk_src_div;
+	struct resource *res;
+
+	i2c = devm_kzalloc(&pdev->dev, sizeof(struct mtk_i2c), GFP_KERNEL);
+	if (i2c == NULL)
+		return -ENOMEM;
+
+	ret = mtk_i2c_parse_dt(pdev->dev.of_node, i2c, &clk_src_div);
+	if (ret)
+		return -EINVAL;
+	if (i2c->have_pmic &&
+			(mtk_get_device_prop(pdev) & COMPAT_MT6577))
+		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);
+
+	i2c->irqnr = platform_get_irq(pdev, 0);
+	if (i2c->irqnr <= 0)
+		return -EINVAL;
+
+	ret = devm_request_irq(&pdev->dev, i2c->irqnr, mtk_i2c_irq,
+		IRQF_TRIGGER_NONE, I2C_DRV_NAME, i2c);
+	if (ret < 0) {
+		dev_err(&pdev->dev,
+			"Request I2C IRQ %d fail\n", i2c->irqnr);
+		return ret;
+	}
+
+	i2c->adap.dev.of_node = pdev->dev.of_node;
+	i2c->dev = &i2c->adap.dev;
+	i2c->adap.dev.parent = &pdev->dev;
+	i2c->adap.owner = THIS_MODULE;
+	i2c->adap.algo = &mtk_i2c_algorithm;
+	i2c->adap.algo_data = NULL;
+	i2c->adap.timeout = 2 * HZ;
+	i2c->adap.retries = 1;
+
+	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);
+	}
+
+	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_src_in_hz = clk_get_rate(i2c->clk_pmic) / clk_src_div;
+	} else {
+		clk_src_in_hz = clk_get_rate(i2c->clk_main) / clk_src_div;
+	}
+
+	dev_dbg(&pdev->dev, "clock source %p,clock src frequency %d\n",
+		i2c->clk_main, clk_src_in_hz);
+	strlcpy(i2c->adap.name, I2C_DRV_NAME, sizeof(i2c->adap.name));
+	init_waitqueue_head(&i2c->wait);
+
+	ret = i2c_set_speed(i2c, clk_src_in_hz);
+	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);
+
+	i2c->dma_buf.vaddr = dma_alloc_coherent(&pdev->dev,
+		PAGE_SIZE, &i2c->dma_buf.paddr, GFP_KERNEL);
+	if (i2c->dma_buf.vaddr == NULL) {
+		dev_err(&pdev->dev, "dma_alloc_coherent fail\n");
+		return -ENOMEM;
+	}
+
+	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");
+		free_i2c_dma_bufs(i2c);
+		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);
+	free_i2c_dma_bufs(i2c);
+	platform_set_drvdata(pdev, NULL);
+
+	return 0;
+}
+
+static struct platform_driver mtk_i2c_driver = {
+	.probe = mtk_i2c_probe,
+	.remove = mtk_i2c_remove,
+	.driver = {
+		.name = I2C_DRV_NAME,
+		.owner = THIS_MODULE,
+		.of_match_table = of_match_ptr(mtk_i2c_of_match),
+	},
+};
+
+module_platform_driver(mtk_i2c_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("MediaTek I2C Bus Driver");
+MODULE_AUTHOR("Xudong Chen <xudong.chen@mediatek.com>");
-- 
1.8.1.1.dirty

Re: [PATCH v2 0/3] ARM: mediatek: Add driver for Mediatek I2C controller

[xudong chen]

Hi,

I have modify the code according the comment in patch v2.
Is the any other suggestion or question for this patch?

If this patch is OK, how to merger this patch? Because of the dtsi 
dependency patch v2 can't be merged now, can we just merge dt-bindings
and I2C common driver?

Thanks!


On Tue, 2014-11-04 at 13:29 +0800, Xudong Chen wrote:
> This series is the second version of Mediatek SoCs I2C controller common
> bus driver.
> Compared to the first version,
> 1. Add comment for feature have-pmic in dt-bindings file i2c-mt6577.txt.
> 2. Add notes for I2C4/5/6 in mt8135.dtsi.
> 3. Add check compatible for the feature have-pmic in i2c-mt65xx.c, if set
> have-pmic for the compatible mt6577 the driver will return error.
> 
> Because the clock driver for mediatek SoC is not ready yet(still work in
> progress), so I delete the related clock code in dtsi file for now.
> 
> This driver is based on 3.18-rc1 & Hongzhou's gpio patch.
> 
> MTK I2C HW has some limitation.
> 1. If the i2c_msg number is more than one, STOP will be issued instead of
> RS(Repeat Start) between each message.
> Such as: "START + ADDR + DATA_n + STOP + START + ADDR + DATA_n + STOP ..."
> 
> 2. Mediatek I2C controller support WRRD(write then read) mode, in WRRD
> mode the Repeat Start will be issued between 2 messages.
> In this driver if 2 messages is first write then read, the driver will
> combine 2 messages using Write-Read mode so the RS will be issued between
> the 2 messages.
> Ex: W/R/R, driver will combine first W/R and then R.
> The data series will be:
> "START + WriteADDR + DATA + RS + ReadADDR + DATA + STOP + START + ReadADDR +
> DATA + STOP".
> 
> 3. Due to HW limitation, in this version the max transfer data length is 255
> in one message. If want to transfer more than 255 bytes, HW needs the SW
> driver to split the data. Take 600 bytes for example, the data need to be
> divided into 3 parts 255 + 255 + 90. The data series will be:
> "START + ADDR + DATA_255 + RS + ADDR + DATA_255 + RS + ADDR +  DATA_90 + STOP"
> instead of "START + ADDR + DATA_900 + STOP".
> We haven't implement this yet, we will do this in the separate patch.
> 
> MT8135 and MT6589 can control I2C pins on PMIC(MT6397) by setting the i2c
> registers in MT8135 side. In this case, driver should set OFFSET_PATH_DIR
> bit first, the operation on other registers are still the same.
> For now MT6589/MT8135 support this, MT6577/MT6595/MT8127 do not support.
> For example, If want to use I2C4/5/6 pins on MT8135 just need to enable
> the pinmux, else if want to use I2C pins on PMIC(MT6397) just need to add
> "mediatek,have-pmic" property in the .dts file of each platform.
> 
> Xudong Chen (3):
>   dt-bindings: Add I2C bindings for mt65xx/mt81xx.
>   ARM: mediatek: Add I2C node for mt8135 and mt8127
>   I2C: mediatek: Add driver for MediaTek I2C controller
> 
>  .../devicetree/bindings/i2c/i2c-mt6577.txt         |  39 ++
>  arch/arm/boot/dts/mt8127.dtsi                      |  27 +
>  arch/arm/boot/dts/mt8135.dtsi                      |  90 +++
>  drivers/i2c/busses/Kconfig                         |   9 +
>  drivers/i2c/busses/Makefile                        |   1 +
>  drivers/i2c/busses/i2c-mt65xx.c                    | 742 +++++++++++++++++++++
>  6 files changed, 908 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/i2c/i2c-mt6577.txt
>  create mode 100644 drivers/i2c/busses/i2c-mt65xx.c
> 
> --
> 1.8.1.1.dirty
> 

Re: [PATCH v2 1/3] dt-bindings: Add I2C bindings for mt65xx/mt81xx.

[Wolfram Sang]

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On Tue, Nov 04, 2014 at 01:29:35PM +0800, Xudong Chen wrote:
> Add devicetree bindings for Mediatek Soc I2C driver.
> 
> Signed-off-by: Xudong Chen <xudong.chen@mediatek.com>
> ---
>  .../devicetree/bindings/i2c/i2c-mt6577.txt         | 39 ++++++++++++++++++++++
>  1 file changed, 39 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/i2c/i2c-mt6577.txt
> 
> diff --git a/Documentation/devicetree/bindings/i2c/i2c-mt6577.txt b/Documentation/devicetree/bindings/i2c/i2c-mt6577.txt
> new file mode 100644
> index 0000000..733e65e
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/i2c/i2c-mt6577.txt
> @@ -0,0 +1,39 @@
> +* 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.
> +  - 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.

? Doesn't that platform have CCF and can't we derive an I2C clock there?

> +  - clocks: clock name from clock manager
> +  - clock-names: clock name used in i2c driver probe

This needs names of the clocks. Check other binding documentation for
examples.

> +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,have-dcm: platform has DCM(hardware digital clock manager) property.
> +  - mediatek,use-push-pull: IO use push-pull mode.

About the last 3 ones: Can't we encode this in the driver? Like, if the
compatible is "mediatek,mt6589-i2c" we know it has this and that but not
this?

> +
> +Example:
> +
> +	i2c0: i2c@1100d000 {
> +			compatible = "mediatek,mt6577-i2c";
> +			reg = <0x1100d000 0x70>,
> +			      <0x11000300 0x80>;
> +			interrupts = <GIC_SPI 44 IRQ_TYPE_LEVEL_LOW>;
> +			clock-frequency = <100000>;
> +			mediatek,have-pmic;
> +			clock-div = <16>;
> +			clocks = <&i2c0_ck>, <&ap_dma_ck>;
> +			clock-names = "main", "dma";
> +	};
> +
> -- 
> 1.8.1.1.dirty
> 

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Re: [PATCH v2 0/3] ARM: mediatek: Add driver for Mediatek I2C controller

[Wolfram Sang]

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> MTK I2C HW has some limitation.
> 1. If the i2c_msg number is more than one, STOP will be issued instead of
> RS(Repeat Start) between each message.
> 
> 2. Mediatek I2C controller support WRRD(write then read) mode, in WRRD
> mode the Repeat Start will be issued between 2 messages.
> In this driver if 2 messages is first write then read, the driver will
> combine 2 messages using Write-Read mode so the RS will be issued between
> the 2 messages.
> Ex: W/R/R, driver will combine first W/R and then R.
> 
> 3. Due to HW limitation, in this version the max transfer data length is 255
> in one message.

This looks to me more like an SMBUS controller instead of I2C. Maybe you
should populate smbus_xfer rather than master_xfer?

> MT8135 and MT6589 can control I2C pins on PMIC(MT6397) by setting the i2c
> registers in MT8135 side.

I still didn't get this, even after reading the mail thread of old
series. Can someone maybe draw me a nice ASCII picture showing the setup
which is going on here?


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Re: [PATCH v2 0/3] ARM: mediatek: Add driver for Mediatek I2C controller

[xudong chen]

On Thu, 2014-11-13 at 19:31 +0100, Wolfram Sang wrote:
> > MTK I2C HW has some limitation.
> > 1. If the i2c_msg number is more than one, STOP will be issued instead of
> > RS(Repeat Start) between each message.
> > 
> > 2. Mediatek I2C controller support WRRD(write then read) mode, in WRRD
> > mode the Repeat Start will be issued between 2 messages.
> > In this driver if 2 messages is first write then read, the driver will
> > combine 2 messages using Write-Read mode so the RS will be issued between
> > the 2 messages.
> > Ex: W/R/R, driver will combine first W/R and then R.
> > 
> > 3. Due to HW limitation, in this version the max transfer data length is 255
> > in one message.
> 
> This looks to me more like an SMBUS controller instead of I2C. Maybe you
> should populate smbus_xfer rather than master_xfer?

This is the HW limitation, we will try to workaround this in the
separate patch.

> 
> > MT8135 and MT6589 can control I2C pins on PMIC(MT6397) by setting the i2c
> > registers in MT8135 side.
> 
> I still didn't get this, even after reading the mail thread of old
> series. Can someone maybe draw me a nice ASCII picture showing the setup
> which is going on here?
> 

1. The DIR_PATH register is in MT8135.
2. All the registers used in the driver are in MT8135.
3. If want I2C wave go/from PMIC need to set the DIR_PATH register bit^0
to 1 extra.

>From the picture:
If MT8135 connected to PMIC(MT6397), when set the DIR_PATH register
bit^0 to 1, the HW will transfer the i2c wave from pins(SDA4_pmic &
SCL4_pmic) on MT6397 side.
If want use pins(SDA4 & SCL4) on 8135 side directly, we should set the
DIR_PATH register bit^0 to 0.

_______       ________
|      |______|       |
|      |      |  PMIC |
| 8135 |______| (6397)|___SDA4_pmic
|      |      |       |___SCL4_pmic
!______!      !_______!
  |   |
SDA4 SCL4


Thanks!

Re: [PATCH v2 1/3] dt-bindings: Add I2C bindings for mt65xx/mt81xx.

[xudong chen]

On Thu, 2014-11-13 at 19:16 +0100, Wolfram Sang wrote:
> On Tue, Nov 04, 2014 at 01:29:35PM +0800, Xudong Chen wrote:
> > Add devicetree bindings for Mediatek Soc I2C driver.
> > 
> > Signed-off-by: Xudong Chen <xudong.chen@mediatek.com>
> > ---
> >  .../devicetree/bindings/i2c/i2c-mt6577.txt         | 39 ++++++++++++++++++++++
> >  1 file changed, 39 insertions(+)
> >  create mode 100644 Documentation/devicetree/bindings/i2c/i2c-mt6577.txt
> > 
> > diff --git a/Documentation/devicetree/bindings/i2c/i2c-mt6577.txt b/Documentation/devicetree/bindings/i2c/i2c-mt6577.txt
> > new file mode 100644
> > index 0000000..733e65e
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/i2c/i2c-mt6577.txt
> > @@ -0,0 +1,39 @@
> > +* 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.
> > +  - 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.
> 
> ? Doesn't that platform have CCF and can't we derive an I2C clock there?
> 
This value is fixed and is different from each chip. It cannot be get
from the CCF.

> > +  - clocks: clock name from clock manager
> > +  - clock-names: clock name used in i2c driver probe
> 
> This needs names of the clocks. Check other binding documentation for
> examples.
> 
OK I will add the names.
> > +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,have-dcm: platform has DCM(hardware digital clock manager) property.
> > +  - mediatek,use-push-pull: IO use push-pull mode.
> 
> About the last 3 ones: Can't we encode this in the driver? Like, if the
> compatible is "mediatek,mt6589-i2c" we know it has this and that but not
> this?
> 
Yes, the DCM can be moved to the driver, but the pmic and push-pull
cannot encode in the driver.
Because Mediatek i2c IO-config compatible with open-drain and push-pull
mode, some devices use push-pull mode, so need set this in dts.
The PMIC feature can use the pins on PMIC(mt6397) side, if do not set
this the driver will use the I2C pins on the master chip.
I will try to explain more detail for PMIC in the other mail thread.

> > +
> > +Example:
> > +
> > +	i2c0: i2c@1100d000 {
> > +			compatible = "mediatek,mt6577-i2c";
> > +			reg = <0x1100d000 0x70>,
> > +			      <0x11000300 0x80>;
> > +			interrupts = <GIC_SPI 44 IRQ_TYPE_LEVEL_LOW>;
> > +			clock-frequency = <100000>;
> > +			mediatek,have-pmic;
> > +			clock-div = <16>;
> > +			clocks = <&i2c0_ck>, <&ap_dma_ck>;
> > +			clock-names = "main", "dma";
> > +	};
> > +
> > -- 
> > 1.8.1.1.dirty
> > 

Re: [PATCH v2 0/3] ARM: mediatek: Add driver for Mediatek I2C controller

[Yingjoe Chen]

On Fri, 2014-11-14 at 11:12 +0800, xudong chen wrote:
> On Thu, 2014-11-13 at 19:31 +0100, Wolfram Sang wrote:
> > > MT8135 and MT6589 can control I2C pins on PMIC(MT6397) by setting the i2c
> > > registers in MT8135 side.
> > 
> > I still didn't get this, even after reading the mail thread of old
> > series. Can someone maybe draw me a nice ASCII picture showing the setup
> > which is going on here?
> > 
> 
> 1. The DIR_PATH register is in MT8135.
> 2. All the registers used in the driver are in MT8135.
> 3. If want I2C wave go/from PMIC need to set the DIR_PATH register bit^0
> to 1 extra.

Hi,

Some supplemental, I hope this make it more clear.

    +---------------+
    |     MT8135    |
    |               |
    |    +----------|
    |    |I2C       |___SDA
    |    |controller|___SCL
    |    +----------|
    |               |      +-------+
    |    +----------|      | MT6397|
    |    |  pwrap   |      |       |___SDA_pmic
    |    |          |<---->|       |___SCL_pmic
    +---------------+      +-------+

This is the simplified block diagram of mt8135 and mt6397. MT8135 can
works with MTK PMIC MT6397. On MT8135, it use pwrap module to control
/communicate with the PMIC. Pwrap is a hardware communicate with pmic
through MTK proprietary interface.

There are several PMIC functionality that is controlled by registers
and controllers on MT8135, I2C is one of them.

On MT8135, I2C controller can control I2C pins on MT8135 and MT6397.
When you set I2C DIR_PATH register on MT8135, i2c controller will
control PMIC pins(through pwrap) to send i2c signal. Because the
i2c controllers are on 8135, it can still do DMA from system memory.
So it kinds of like these 2 works like a virtual SoC.

Joe.C

Re: [PATCH v2 0/3] ARM: mediatek: Add driver for Mediatek I2C controller

[xudong chen]

On Fri, 2014-11-14 at 11:12 +0800, xudong chen wrote:
> On Thu, 2014-11-13 at 19:31 +0100, Wolfram Sang wrote:
> > > MTK I2C HW has some limitation.
> > > 1. If the i2c_msg number is more than one, STOP will be issued instead of
> > > RS(Repeat Start) between each message.
> > > 
> > > 2. Mediatek I2C controller support WRRD(write then read) mode, in WRRD
> > > mode the Repeat Start will be issued between 2 messages.
> > > In this driver if 2 messages is first write then read, the driver will
> > > combine 2 messages using Write-Read mode so the RS will be issued between
> > > the 2 messages.
> > > Ex: W/R/R, driver will combine first W/R and then R.
> > > 
> > > 3. Due to HW limitation, in this version the max transfer data length is 255
> > > in one message.
> > 
> > This looks to me more like an SMBUS controller instead of I2C. Maybe you
> > should populate smbus_xfer rather than master_xfer?
> 
> This is the HW limitation, we will try to workaround this in the
> separate patch.
> 
Except limited RS and limited length support, our HW follow I2C protocol
spec.
The length is compatible with most I2C devices, only a few I2C devices
need transfer more than 255 bytes.
The future Mediatek IC will fix the RS and length limitation.

Thanks!
> 
>