Merge branch 'i2c/for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux (8f5d2708) · Commits · 戴 / test

Documentation/devicetree/bindings/i2c/i2c-rk3x.txt

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		* Rockchip RK3xxx I2C controller

		This driver interfaces with the native I2C controller present in Rockchip
		RK3xxx SoCs.

		Required properties :

		- reg : Offset and length of the register set for the device
		- compatible : should be "rockchip,rk3066-i2c", "rockchip,rk3188-i2c" or
		"rockchip,rk3288-i2c".
		- interrupts : interrupt number
		- clocks : parent clock

		Required on RK3066, RK3188 :

		- rockchip,grf : the phandle of the syscon node for the general register
		file (GRF)
		- on those SoCs an alias with the correct I2C bus ID (bit offset in the GRF)
		is also required.

		Optional properties :

		- clock-frequency : SCL frequency to use (in Hz). If omitted, 100kHz is used.

		Example:

		aliases {
		i2c0 = &i2c0;
		}

		i2c0: i2c@2002d000 {
		compatible = "rockchip,rk3188-i2c";
		reg = <0x2002d000 0x1000>;
		interrupts = <GIC_SPI 40 IRQ_TYPE_LEVEL_HIGH>;
		#address-cells = <1>;
		#size-cells = <0>;

		rockchip,grf = <&grf>;

		clock-names = "i2c";
		clocks = <&cru PCLK_I2C0>;
		};

Documentation/devicetree/bindings/i2c/i2c-sunxi-p2wi.txt

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		* Allwinner P2WI (Push/Pull 2 Wire Interface) controller

		Required properties :

		- reg : Offset and length of the register set for the device.
		- compatible : Should one of the following:
		- "allwinner,sun6i-a31-p2wi"
		- interrupts : The interrupt line connected to the P2WI peripheral.
		- clocks : The gate clk connected to the P2WI peripheral.
		- resets : The reset line connected to the P2WI peripheral.

		Optional properties :

		- clock-frequency : Desired P2WI bus clock frequency in Hz. If not set the
		default frequency is 100kHz

		A P2WI may contain one child node encoding a P2WI slave device.

		Slave device properties:
		Required properties:
		- reg : the I2C slave address used during the initialization
		process to switch from I2C to P2WI mode

		Example:

		p2wi@01f03400 {
		compatible = "allwinner,sun6i-a31-p2wi";
		reg = <0x01f03400 0x400>;
		interrupts = <0 39 4>;
		clocks = <&apb0_gates 3>;
		clock-frequency = <6000000>;
		resets = <&apb0_rst 3>;

		axp221: pmic@68 {
		compatible = "x-powers,axp221";
		reg = <0x68>;

		/* ... */
		};
		};

drivers/i2c/busses/Kconfig

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Original line number	Diff line number	Diff line
		@@ -676,6 +676,16 @@ config I2C_RIIC
		This driver can also be built as a module. If so, the module
		will be called i2c-riic.

		config I2C_RK3X
		tristate "Rockchip RK3xxx I2C adapter"
		depends on OF
		help
		Say Y here to include support for the I2C adapter in Rockchip RK3xxx
		SoCs.

		This driver can also be built as a module. If so, the module will
		be called i2c-rk3x.

		config HAVE_S3C2410_I2C
		bool
		help
		@@ -764,6 +774,19 @@ config I2C_STU300
		This driver can also be built as a module. If so, the module
		will be called i2c-stu300.

		config I2C_SUN6I_P2WI
		tristate "Allwinner sun6i internal P2WI controller"
		depends on RESET_CONTROLLER
		depends on MACH_SUN6I \|\| COMPILE_TEST
		help
		If you say yes to this option, support will be included for the
		P2WI (Push/Pull 2 Wire Interface) controller embedded in some sunxi
		SOCs.
		The P2WI looks like an SMBus controller (which supports only byte
		accesses), except that it only supports one slave device.
		This interface is used to connect to specific PMIC devices (like the
		AXP221).

		config I2C_TEGRA
		tristate "NVIDIA Tegra internal I2C controller"
		depends on ARCH_TEGRA

drivers/i2c/busses/Makefile

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Original line number	Diff line number	Diff line
		@@ -66,6 +66,7 @@ obj-$(CONFIG_I2C_PXA) += i2c-pxa.o
		obj-$(CONFIG_I2C_PXA_PCI) += i2c-pxa-pci.o
		obj-$(CONFIG_I2C_QUP) += i2c-qup.o
		obj-$(CONFIG_I2C_RIIC) += i2c-riic.o
		obj-$(CONFIG_I2C_RK3X) += i2c-rk3x.o
		obj-$(CONFIG_I2C_S3C2410) += i2c-s3c2410.o
		obj-$(CONFIG_I2C_S6000) += i2c-s6000.o
		obj-$(CONFIG_I2C_SH7760) += i2c-sh7760.o
		@@ -74,6 +75,7 @@ obj-$(CONFIG_I2C_SIMTEC) += i2c-simtec.o
		obj-$(CONFIG_I2C_SIRF) += i2c-sirf.o
		obj-$(CONFIG_I2C_ST) += i2c-st.o
		obj-$(CONFIG_I2C_STU300) += i2c-stu300.o
		obj-$(CONFIG_I2C_SUN6I_P2WI) += i2c-sun6i-p2wi.o
		obj-$(CONFIG_I2C_TEGRA) += i2c-tegra.o
		obj-$(CONFIG_I2C_VERSATILE) += i2c-versatile.o
		obj-$(CONFIG_I2C_WMT) += i2c-wmt.o

drivers/i2c/busses/i2c-rk3x.c

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		/*
		* Driver for I2C adapter in Rockchip RK3xxx SoC
		*
		* Max Schwarz <max.schwarz@online.de>
		* based on the patches by Rockchip Inc.
		*
		* 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/interrupt.h>
		#include <linux/errno.h>
		#include <linux/err.h>
		#include <linux/platform_device.h>
		#include <linux/io.h>
		#include <linux/of_address.h>
		#include <linux/of_irq.h>
		#include <linux/spinlock.h>
		#include <linux/clk.h>
		#include <linux/wait.h>
		#include <linux/mfd/syscon.h>
		#include <linux/regmap.h>


		/* Register Map */
		#define REG_CON 0x00 /* control register */
		#define REG_CLKDIV 0x04 /* clock divisor register */
		#define REG_MRXADDR 0x08 /* slave address for REGISTER_TX */
		#define REG_MRXRADDR 0x0c /* slave register address for REGISTER_TX */
		#define REG_MTXCNT 0x10 /* number of bytes to be transmitted */
		#define REG_MRXCNT 0x14 /* number of bytes to be received */
		#define REG_IEN 0x18 /* interrupt enable */
		#define REG_IPD 0x1c /* interrupt pending */
		#define REG_FCNT 0x20 /* finished count */

		/* Data buffer offsets */
		#define TXBUFFER_BASE 0x100
		#define RXBUFFER_BASE 0x200

		/* REG_CON bits */
		#define REG_CON_EN BIT(0)
		enum {
		REG_CON_MOD_TX = 0, /* transmit data */
		REG_CON_MOD_REGISTER_TX, /* select register and restart */
		REG_CON_MOD_RX, /* receive data */
		REG_CON_MOD_REGISTER_RX, /* broken: transmits read addr AND writes
		* register addr */
		};
		#define REG_CON_MOD(mod) ((mod) << 1)
		#define REG_CON_MOD_MASK (BIT(1) \| BIT(2))
		#define REG_CON_START BIT(3)
		#define REG_CON_STOP BIT(4)
		#define REG_CON_LASTACK BIT(5) /* 1: send NACK after last received byte */
		#define REG_CON_ACTACK BIT(6) /* 1: stop if NACK is received */

		/* REG_MRXADDR bits */
		#define REG_MRXADDR_VALID(x) BIT(24 + (x)) /* [x8+7:x8] of MRX[R]ADDR valid */

		/* REG_IEN/REG_IPD bits */
		#define REG_INT_BTF BIT(0) /* a byte was transmitted */
		#define REG_INT_BRF BIT(1) /* a byte was received */
		#define REG_INT_MBTF BIT(2) /* master data transmit finished */
		#define REG_INT_MBRF BIT(3) /* master data receive finished */
		#define REG_INT_START BIT(4) /* START condition generated */
		#define REG_INT_STOP BIT(5) /* STOP condition generated */
		#define REG_INT_NAKRCV BIT(6) /* NACK received */
		#define REG_INT_ALL 0x7f

		/* Constants */
		#define WAIT_TIMEOUT 200 /* ms */
		#define DEFAULT_SCL_RATE (100 * 1000) /* Hz */

		enum rk3x_i2c_state {
		STATE_IDLE,
		STATE_START,
		STATE_READ,
		STATE_WRITE,
		STATE_STOP
		};

		/**
		* @grf_offset: offset inside the grf regmap for setting the i2c type
		*/
		struct rk3x_i2c_soc_data {
		int grf_offset;
		};

		struct rk3x_i2c {
		struct i2c_adapter adap;
		struct device *dev;
		struct rk3x_i2c_soc_data *soc_data;

		/* Hardware resources */
		void __iomem *regs;
		struct clk *clk;

		/* Settings */
		unsigned int scl_frequency;

		/* Synchronization & notification */
		spinlock_t lock;
		wait_queue_head_t wait;
		bool busy;

		/* Current message */
		struct i2c_msg *msg;
		u8 addr;
		unsigned int mode;
		bool is_last_msg;

		/* I2C state machine */
		enum rk3x_i2c_state state;
		unsigned int processed; /* sent/received bytes */
		int error;
		};

		static inline void i2c_writel(struct rk3x_i2c *i2c, u32 value,
		unsigned int offset)
		{
		writel(value, i2c->regs + offset);
		}

		static inline u32 i2c_readl(struct rk3x_i2c *i2c, unsigned int offset)
		{
		return readl(i2c->regs + offset);
		}

		/* Reset all interrupt pending bits */
		static inline void rk3x_i2c_clean_ipd(struct rk3x_i2c *i2c)
		{
		i2c_writel(i2c, REG_INT_ALL, REG_IPD);
		}

		/**
		* Generate a START condition, which triggers a REG_INT_START interrupt.
		*/
		static void rk3x_i2c_start(struct rk3x_i2c *i2c)
		{
		u32 val;

		rk3x_i2c_clean_ipd(i2c);
		i2c_writel(i2c, REG_INT_START, REG_IEN);

		/* enable adapter with correct mode, send START condition */
		val = REG_CON_EN \| REG_CON_MOD(i2c->mode) \| REG_CON_START;

		/* if we want to react to NACK, set ACTACK bit */
		if (!(i2c->msg->flags & I2C_M_IGNORE_NAK))
		val \|= REG_CON_ACTACK;

		i2c_writel(i2c, val, REG_CON);
		}

		/**
		* Generate a STOP condition, which triggers a REG_INT_STOP interrupt.
		*
		* @error: Error code to return in rk3x_i2c_xfer
		*/
		static void rk3x_i2c_stop(struct rk3x_i2c *i2c, int error)
		{
		unsigned int ctrl;

		i2c->processed = 0;
		i2c->msg = NULL;
		i2c->error = error;

		if (i2c->is_last_msg) {
		/* Enable stop interrupt */
		i2c_writel(i2c, REG_INT_STOP, REG_IEN);

		i2c->state = STATE_STOP;

		ctrl = i2c_readl(i2c, REG_CON);
		ctrl \|= REG_CON_STOP;
		i2c_writel(i2c, ctrl, REG_CON);
		} else {
		/* Signal rk3x_i2c_xfer to start the next message. */
		i2c->busy = false;
		i2c->state = STATE_IDLE;

		/*
		* The HW is actually not capable of REPEATED START. But we can
		* get the intended effect by resetting its internal state
		* and issuing an ordinary START.
		*/
		i2c_writel(i2c, 0, REG_CON);

		/* signal that we are finished with the current msg */
		wake_up(&i2c->wait);
		}
		}

		/**
		* Setup a read according to i2c->msg
		*/
		static void rk3x_i2c_prepare_read(struct rk3x_i2c *i2c)
		{
		unsigned int len = i2c->msg->len - i2c->processed;
		u32 con;

		con = i2c_readl(i2c, REG_CON);

		/*
		* The hw can read up to 32 bytes at a time. If we need more than one
		* chunk, send an ACK after the last byte of the current chunk.
		*/
		if (unlikely(len > 32)) {
		len = 32;
		con &= ~REG_CON_LASTACK;
		} else {
		con \|= REG_CON_LASTACK;
		}

		/* make sure we are in plain RX mode if we read a second chunk */
		if (i2c->processed != 0) {
		con &= ~REG_CON_MOD_MASK;
		con \|= REG_CON_MOD(REG_CON_MOD_RX);
		}

		i2c_writel(i2c, con, REG_CON);
		i2c_writel(i2c, len, REG_MRXCNT);
		}

		/**
		* Fill the transmit buffer with data from i2c->msg
		*/
		static void rk3x_i2c_fill_transmit_buf(struct rk3x_i2c *i2c)
		{
		unsigned int i, j;
		u32 cnt = 0;
		u32 val;
		u8 byte;

		for (i = 0; i < 8; ++i) {
		val = 0;
		for (j = 0; j < 4; ++j) {
		if (i2c->processed == i2c->msg->len)
		break;

		if (i2c->processed == 0 && cnt == 0)
		byte = (i2c->addr & 0x7f) << 1;
		else
		byte = i2c->msg->buf[i2c->processed++];

		val \|= byte << (j * 8);
		cnt++;
		}

		i2c_writel(i2c, val, TXBUFFER_BASE + 4 * i);

		if (i2c->processed == i2c->msg->len)
		break;
		}

		i2c_writel(i2c, cnt, REG_MTXCNT);
		}


		/* IRQ handlers for individual states */

		static void rk3x_i2c_handle_start(struct rk3x_i2c *i2c, unsigned int ipd)
		{
		if (!(ipd & REG_INT_START)) {
		rk3x_i2c_stop(i2c, -EIO);
		dev_warn(i2c->dev, "unexpected irq in START: 0x%x\n", ipd);
		rk3x_i2c_clean_ipd(i2c);
		return;
		}

		/* ack interrupt */
		i2c_writel(i2c, REG_INT_START, REG_IPD);

		/* disable start bit */
		i2c_writel(i2c, i2c_readl(i2c, REG_CON) & ~REG_CON_START, REG_CON);

		/* enable appropriate interrupts and transition */
		if (i2c->mode == REG_CON_MOD_TX) {
		i2c_writel(i2c, REG_INT_MBTF \| REG_INT_NAKRCV, REG_IEN);
		i2c->state = STATE_WRITE;
		rk3x_i2c_fill_transmit_buf(i2c);
		} else {
		/* in any other case, we are going to be reading. */
		i2c_writel(i2c, REG_INT_MBRF \| REG_INT_NAKRCV, REG_IEN);
		i2c->state = STATE_READ;
		rk3x_i2c_prepare_read(i2c);
		}
		}

		static void rk3x_i2c_handle_write(struct rk3x_i2c *i2c, unsigned int ipd)
		{
		if (!(ipd & REG_INT_MBTF)) {
		rk3x_i2c_stop(i2c, -EIO);
		dev_err(i2c->dev, "unexpected irq in WRITE: 0x%x\n", ipd);
		rk3x_i2c_clean_ipd(i2c);
		return;
		}

		/* ack interrupt */
		i2c_writel(i2c, REG_INT_MBTF, REG_IPD);

		/* are we finished? */
		if (i2c->processed == i2c->msg->len)
		rk3x_i2c_stop(i2c, i2c->error);
		else
		rk3x_i2c_fill_transmit_buf(i2c);
		}

		static void rk3x_i2c_handle_read(struct rk3x_i2c *i2c, unsigned int ipd)
		{
		unsigned int i;
		unsigned int len = i2c->msg->len - i2c->processed;
		u32 uninitialized_var(val);
		u8 byte;

		/* we only care for MBRF here. */
		if (!(ipd & REG_INT_MBRF))
		return;

		/* ack interrupt */
		i2c_writel(i2c, REG_INT_MBRF, REG_IPD);

		/* read the data from receive buffer */
		for (i = 0; i < len; ++i) {
		if (i % 4 == 0)
		val = i2c_readl(i2c, RXBUFFER_BASE + (i / 4) * 4);

		byte = (val >> ((i % 4) * 8)) & 0xff;
		i2c->msg->buf[i2c->processed++] = byte;
		}

		/* are we finished? */
		if (i2c->processed == i2c->msg->len)
		rk3x_i2c_stop(i2c, i2c->error);
		else
		rk3x_i2c_prepare_read(i2c);
		}

		static void rk3x_i2c_handle_stop(struct rk3x_i2c *i2c, unsigned int ipd)
		{
		unsigned int con;

		if (!(ipd & REG_INT_STOP)) {
		rk3x_i2c_stop(i2c, -EIO);
		dev_err(i2c->dev, "unexpected irq in STOP: 0x%x\n", ipd);
		rk3x_i2c_clean_ipd(i2c);
		return;
		}

		/* ack interrupt */
		i2c_writel(i2c, REG_INT_STOP, REG_IPD);

		/* disable STOP bit */
		con = i2c_readl(i2c, REG_CON);
		con &= ~REG_CON_STOP;
		i2c_writel(i2c, con, REG_CON);

		i2c->busy = false;
		i2c->state = STATE_IDLE;

		/* signal rk3x_i2c_xfer that we are finished */
		wake_up(&i2c->wait);
		}

		static irqreturn_t rk3x_i2c_irq(int irqno, void *dev_id)
		{
		struct rk3x_i2c *i2c = dev_id;
		unsigned int ipd;

		spin_lock(&i2c->lock);

		ipd = i2c_readl(i2c, REG_IPD);
		if (i2c->state == STATE_IDLE) {
		dev_warn(i2c->dev, "irq in STATE_IDLE, ipd = 0x%x\n", ipd);
		rk3x_i2c_clean_ipd(i2c);
		goto out;
		}

		dev_dbg(i2c->dev, "IRQ: state %d, ipd: %x\n", i2c->state, ipd);

		/* Clean interrupt bits we don't care about */
		ipd &= ~(REG_INT_BRF \| REG_INT_BTF);

		if (ipd & REG_INT_NAKRCV) {
		/*
		* We got a NACK in the last operation. Depending on whether
		* IGNORE_NAK is set, we have to stop the operation and report
		* an error.
		*/
		i2c_writel(i2c, REG_INT_NAKRCV, REG_IPD);

		ipd &= ~REG_INT_NAKRCV;

		if (!(i2c->msg->flags & I2C_M_IGNORE_NAK))
		rk3x_i2c_stop(i2c, -ENXIO);
		}

		/* is there anything left to handle? */
		if (unlikely(ipd == 0))
		goto out;

		switch (i2c->state) {
		case STATE_START:
		rk3x_i2c_handle_start(i2c, ipd);
		break;
		case STATE_WRITE:
		rk3x_i2c_handle_write(i2c, ipd);
		break;
		case STATE_READ:
		rk3x_i2c_handle_read(i2c, ipd);
		break;
		case STATE_STOP:
		rk3x_i2c_handle_stop(i2c, ipd);
		break;
		case STATE_IDLE:
		break;
		}

		out:
		spin_unlock(&i2c->lock);
		return IRQ_HANDLED;
		}

		static void rk3x_i2c_set_scl_rate(struct rk3x_i2c *i2c, unsigned long scl_rate)
		{
		unsigned long i2c_rate = clk_get_rate(i2c->clk);
		unsigned int div;

		/* SCL rate = (clk rate) / (8 * DIV) */
		div = DIV_ROUND_UP(i2c_rate, scl_rate * 8);

		/* The lower and upper half of the CLKDIV reg describe the length of
		* SCL low & high periods. */
		div = DIV_ROUND_UP(div, 2);

		i2c_writel(i2c, (div << 16) \| (div & 0xffff), REG_CLKDIV);
		}

		/**
		* Setup I2C registers for an I2C operation specified by msgs, num.
		*
		* Must be called with i2c->lock held.
		*
		* @msgs: I2C msgs to process
		* @num: Number of msgs
		*
		* returns: Number of I2C msgs processed or negative in case of error
		*/
		static int rk3x_i2c_setup(struct rk3x_i2c i2c, struct i2c_msg msgs, int num)
		{
		u32 addr = (msgs[0].addr & 0x7f) << 1;
		int ret = 0;

		/*
		* The I2C adapter can issue a small (len < 4) write packet before
		* reading. This speeds up SMBus-style register reads.
		* The MRXADDR/MRXRADDR hold the slave address and the slave register
		* address in this case.
		*/

		if (num >= 2 && msgs[0].len < 4 &&
		!(msgs[0].flags & I2C_M_RD) && (msgs[1].flags & I2C_M_RD)) {
		u32 reg_addr = 0;
		int i;

		dev_dbg(i2c->dev, "Combined write/read from addr 0x%x\n",
		addr >> 1);

		/* Fill MRXRADDR with the register address(es) */
		for (i = 0; i < msgs[0].len; ++i) {
		reg_addr \|= msgs[0].buf[i] << (i * 8);
		reg_addr \|= REG_MRXADDR_VALID(i);
		}

		/* msgs[0] is handled by hw. */
		i2c->msg = &msgs[1];

		i2c->mode = REG_CON_MOD_REGISTER_TX;

		i2c_writel(i2c, addr \| REG_MRXADDR_VALID(0), REG_MRXADDR);
		i2c_writel(i2c, reg_addr, REG_MRXRADDR);

		ret = 2;
		} else {
		/*
		* We'll have to do it the boring way and process the msgs
		* one-by-one.
		*/

		if (msgs[0].flags & I2C_M_RD) {
		addr \|= 1; /* set read bit */

		/*
		* We have to transmit the slave addr first. Use
		* MOD_REGISTER_TX for that purpose.
		*/
		i2c->mode = REG_CON_MOD_REGISTER_TX;
		i2c_writel(i2c, addr \| REG_MRXADDR_VALID(0),
		REG_MRXADDR);
		i2c_writel(i2c, 0, REG_MRXRADDR);
		} else {
		i2c->mode = REG_CON_MOD_TX;
		}

		i2c->msg = &msgs[0];

		ret = 1;
		}

		i2c->addr = msgs[0].addr;
		i2c->busy = true;
		i2c->state = STATE_START;
		i2c->processed = 0;
		i2c->error = 0;

		rk3x_i2c_clean_ipd(i2c);

		return ret;
		}

		static int rk3x_i2c_xfer(struct i2c_adapter *adap,
		struct i2c_msg *msgs, int num)
		{
		struct rk3x_i2c i2c = (struct rk3x_i2c )adap->algo_data;
		unsigned long timeout, flags;
		int ret = 0;
		int i;

		spin_lock_irqsave(&i2c->lock, flags);

		clk_enable(i2c->clk);

		/* The clock rate might have changed, so setup the divider again */
		rk3x_i2c_set_scl_rate(i2c, i2c->scl_frequency);

		i2c->is_last_msg = false;

		/*
		* Process msgs. We can handle more than one message at once (see
		* rk3x_i2c_setup()).
		*/
		for (i = 0; i < num; i += ret) {
		ret = rk3x_i2c_setup(i2c, msgs + i, num - i);

		if (ret < 0) {
		dev_err(i2c->dev, "rk3x_i2c_setup() failed\n");
		break;
		}

		if (i + ret >= num)
		i2c->is_last_msg = true;

		spin_unlock_irqrestore(&i2c->lock, flags);

		rk3x_i2c_start(i2c);

		timeout = wait_event_timeout(i2c->wait, !i2c->busy,
		msecs_to_jiffies(WAIT_TIMEOUT));

		spin_lock_irqsave(&i2c->lock, flags);

		if (timeout == 0) {
		dev_err(i2c->dev, "timeout, ipd: 0x%02x, state: %d\n",
		i2c_readl(i2c, REG_IPD), i2c->state);

		/* Force a STOP condition without interrupt */
		i2c_writel(i2c, 0, REG_IEN);
		i2c_writel(i2c, REG_CON_EN \| REG_CON_STOP, REG_CON);

		i2c->state = STATE_IDLE;

		ret = -ETIMEDOUT;
		break;
		}

		if (i2c->error) {
		ret = i2c->error;
		break;
		}
		}

		clk_disable(i2c->clk);
		spin_unlock_irqrestore(&i2c->lock, flags);

		return ret;
		}

		static u32 rk3x_i2c_func(struct i2c_adapter *adap)
		{
		return I2C_FUNC_I2C \| I2C_FUNC_SMBUS_EMUL \| I2C_FUNC_PROTOCOL_MANGLING;
		}

		static const struct i2c_algorithm rk3x_i2c_algorithm = {
		.master_xfer = rk3x_i2c_xfer,
		.functionality = rk3x_i2c_func,
		};

		static struct rk3x_i2c_soc_data soc_data[3] = {
		{ .grf_offset = 0x154 }, /* rk3066 */
		{ .grf_offset = 0x0a4 }, /* rk3188 */
		{ .grf_offset = -1 }, /* no I2C switching needed */
		};

		static const struct of_device_id rk3x_i2c_match[] = {
		{ .compatible = "rockchip,rk3066-i2c", .data = (void *)&soc_data[0] },
		{ .compatible = "rockchip,rk3188-i2c", .data = (void *)&soc_data[1] },
		{ .compatible = "rockchip,rk3288-i2c", .data = (void *)&soc_data[2] },
		{},
		};

		static int rk3x_i2c_probe(struct platform_device *pdev)
		{
		struct device_node *np = pdev->dev.of_node;
		const struct of_device_id *match;
		struct rk3x_i2c *i2c;
		struct resource *mem;
		int ret = 0;
		int bus_nr;
		u32 value;
		int irq;

		i2c = devm_kzalloc(&pdev->dev, sizeof(struct rk3x_i2c), GFP_KERNEL);
		if (!i2c)
		return -ENOMEM;

		match = of_match_node(rk3x_i2c_match, np);
		i2c->soc_data = (struct rk3x_i2c_soc_data *)match->data;

		if (of_property_read_u32(pdev->dev.of_node, "clock-frequency",
		&i2c->scl_frequency)) {
		dev_info(&pdev->dev, "using default SCL frequency: %d\n",
		DEFAULT_SCL_RATE);
		i2c->scl_frequency = DEFAULT_SCL_RATE;
		}

		if (i2c->scl_frequency == 0 \|\| i2c->scl_frequency > 400 * 1000) {
		dev_warn(&pdev->dev, "invalid SCL frequency specified.\n");
		dev_warn(&pdev->dev, "using default SCL frequency: %d\n",
		DEFAULT_SCL_RATE);
		i2c->scl_frequency = DEFAULT_SCL_RATE;
		}

		strlcpy(i2c->adap.name, "rk3x-i2c", sizeof(i2c->adap.name));
		i2c->adap.owner = THIS_MODULE;
		i2c->adap.algo = &rk3x_i2c_algorithm;
		i2c->adap.retries = 3;
		i2c->adap.dev.of_node = np;
		i2c->adap.algo_data = i2c;
		i2c->adap.dev.parent = &pdev->dev;

		i2c->dev = &pdev->dev;

		spin_lock_init(&i2c->lock);
		init_waitqueue_head(&i2c->wait);

		i2c->clk = devm_clk_get(&pdev->dev, NULL);
		if (IS_ERR(i2c->clk)) {
		dev_err(&pdev->dev, "cannot get clock\n");
		return PTR_ERR(i2c->clk);
		}

		mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
		i2c->regs = devm_ioremap_resource(&pdev->dev, mem);
		if (IS_ERR(i2c->regs))
		return PTR_ERR(i2c->regs);

		/* Try to set the I2C adapter number from dt */
		bus_nr = of_alias_get_id(np, "i2c");

		/*
		* Switch to new interface if the SoC also offers the old one.
		* The control bit is located in the GRF register space.
		*/
		if (i2c->soc_data->grf_offset >= 0) {
		struct regmap *grf;

		grf = syscon_regmap_lookup_by_phandle(np, "rockchip,grf");
		if (IS_ERR(grf)) {
		dev_err(&pdev->dev,
		"rk3x-i2c needs 'rockchip,grf' property\n");
		return PTR_ERR(grf);
		}

		if (bus_nr < 0) {
		dev_err(&pdev->dev, "rk3x-i2c needs i2cX alias");
		return -EINVAL;
		}

		/* 27+i: write mask, 11+i: value */
		value = BIT(27 + bus_nr) \| BIT(11 + bus_nr);

		ret = regmap_write(grf, i2c->soc_data->grf_offset, value);
		if (ret != 0) {
		dev_err(i2c->dev, "Could not write to GRF: %d\n", ret);
		return ret;
		}
		}

		/* IRQ setup */
		irq = platform_get_irq(pdev, 0);
		if (irq < 0) {
		dev_err(&pdev->dev, "cannot find rk3x IRQ\n");
		return irq;
		}

		ret = devm_request_irq(&pdev->dev, irq, rk3x_i2c_irq,
		0, dev_name(&pdev->dev), i2c);
		if (ret < 0) {
		dev_err(&pdev->dev, "cannot request IRQ\n");
		return ret;
		}

		platform_set_drvdata(pdev, i2c);

		ret = clk_prepare(i2c->clk);
		if (ret < 0) {
		dev_err(&pdev->dev, "Could not prepare clock\n");
		return ret;
		}

		ret = i2c_add_adapter(&i2c->adap);
		if (ret < 0) {
		dev_err(&pdev->dev, "Could not register adapter\n");
		goto err_clk;
		}

		dev_info(&pdev->dev, "Initialized RK3xxx I2C bus at %p\n", i2c->regs);

		return 0;

		err_clk:
		clk_unprepare(i2c->clk);
		return ret;
		}

		static int rk3x_i2c_remove(struct platform_device *pdev)
		{
		struct rk3x_i2c *i2c = platform_get_drvdata(pdev);

		i2c_del_adapter(&i2c->adap);
		clk_unprepare(i2c->clk);

		return 0;
		}

		static struct platform_driver rk3x_i2c_driver = {
		.probe = rk3x_i2c_probe,
		.remove = rk3x_i2c_remove,
		.driver = {
		.owner = THIS_MODULE,
		.name = "rk3x-i2c",
		.of_match_table = rk3x_i2c_match,
		},
		};

		module_platform_driver(rk3x_i2c_driver);

		MODULE_DESCRIPTION("Rockchip RK3xxx I2C Bus driver");
		MODULE_AUTHOR("Max Schwarz <max.schwarz@online.de>");
		MODULE_LICENSE("GPL v2");

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