diff mbox

i2c: vt8500: Add support for Wondermedia I2C master-mode

Message ID 1356658166-18688-1-git-send-email-linux@prisktech.co.nz (mailing list archive)
State New, archived
Headers show

Commit Message

Tony Prisk Dec. 28, 2012, 1:29 a.m. UTC
This patch adds support for the I2C controller found on Wondermedia
SoCs.

Due to the lack of pinmux support, GPIO pin alternate functions are
configured by machine's compatible property, as are pullups.

Signed-off-by: Tony Prisk <linux@prisktech.co.nz>
---
 .../devicetree/bindings/i2c/i2c-vt8500.txt         |   24 +
 drivers/i2c/busses/Kconfig                         |    7 +
 drivers/i2c/busses/Makefile                        |    1 +
 drivers/i2c/busses/i2c-wmt.c                       |  636 ++++++++++++++++++++
 4 files changed, 668 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/i2c/i2c-vt8500.txt
 create mode 100644 drivers/i2c/busses/i2c-wmt.c
diff mbox

Patch

diff --git a/Documentation/devicetree/bindings/i2c/i2c-vt8500.txt b/Documentation/devicetree/bindings/i2c/i2c-vt8500.txt
new file mode 100644
index 0000000..94a425e
--- /dev/null
+++ b/Documentation/devicetree/bindings/i2c/i2c-vt8500.txt
@@ -0,0 +1,24 @@ 
+* Wondermedia I2C Controller
+
+Required properties :
+
+ - compatible : should be "wm,wm8505-i2c"
+ - reg : Offset and length of the register set for the device
+ - interrupts : <IRQ> where IRQ is the interrupt number
+ - clocks : phandle to the I2C clock source
+
+Optional properties :
+
+ - clock-frequency : desired I2C bus clock frequency in Hz.
+	Valid values are 100000 and 400000.
+	Default to 100000 if not specified, or invalid value.
+
+Example :
+
+	i2c_0: i2c@d8280000 {
+		compatible = "wm,wm8505-i2c";
+		reg = <0xd8280000 0x1000>;
+		interrupts = <19>;
+		clocks = <&clki2c0>;
+		clock-frequency = <400000>;
+	};
diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
index bdca511..41270fa 100644
--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -700,6 +700,13 @@  config I2C_VERSATILE
 	  This driver can also be built as a module.  If so, the module
 	  will be called i2c-versatile.
 
+config I2C_WMT
+	tristate "Wondermedia I2C Controller support"
+	depends on ARCH_VT8500
+	help
+	  If you say yes to this option, support will be included for the
+	  I2C controllers found in Wondermedia SoCs.
+
 config I2C_OCTEON
 	tristate "Cavium OCTEON I2C bus support"
 	depends on CPU_CAVIUM_OCTEON
diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
index 6181f3f..dce6299 100644
--- a/drivers/i2c/busses/Makefile
+++ b/drivers/i2c/busses/Makefile
@@ -69,6 +69,7 @@  obj-$(CONFIG_I2C_SIRF)		+= i2c-sirf.o
 obj-$(CONFIG_I2C_STU300)	+= i2c-stu300.o
 obj-$(CONFIG_I2C_TEGRA)		+= i2c-tegra.o
 obj-$(CONFIG_I2C_VERSATILE)	+= i2c-versatile.o
+obj-$(CONFIG_I2C_WMT)		+= i2c-wmt.o
 obj-$(CONFIG_I2C_OCTEON)	+= i2c-octeon.o
 obj-$(CONFIG_I2C_XILINX)	+= i2c-xiic.o
 obj-$(CONFIG_I2C_XLR)		+= i2c-xlr.o
diff --git a/drivers/i2c/busses/i2c-wmt.c b/drivers/i2c/busses/i2c-wmt.c
new file mode 100644
index 0000000..07d86e3
--- /dev/null
+++ b/drivers/i2c/busses/i2c-wmt.c
@@ -0,0 +1,636 @@ 
+/*
+ *  Wondermedia I2C Master Mode Driver
+ *
+ *  Copyright (C) 2012 Tony Prisk <linux@prisktech.co.nz>
+ *
+ *  Derived from GPL licensed source:
+ *  - Copyright (C) 2008 WonderMedia Technologies, 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/clk.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_i2c.h>
+#include <linux/of_irq.h>
+#include <linux/platform_device.h>
+
+#define REG_CR		0x00
+#define REG_TCR		0x02
+#define REG_CSR		0x04
+#define REG_ISR		0x06
+#define REG_IMR		0x08
+#define REG_CDR		0x0A
+#define REG_TR		0x0C
+#define REG_MCR		0x0E
+#define REG_SLAVE_CR	0x10
+#define REG_SLAVE_SR	0x12
+#define REG_SLAVE_ISR	0x14
+#define REG_SLAVE_IMR	0x16
+#define REG_SLAVE_DR	0x18
+#define REG_SLAVE_TR	0x1A
+
+/* REG_CR Bit fields */
+#define CR_TX_NEXT_ACK		0x0000
+#define CR_ENABLE		0x0001
+#define CR_TX_NEXT_NO_ACK	0x0002
+#define CR_TX_END		0x0004
+#define CR_CPU_RDY		0x0008
+#define SLAV_MODE_SEL		0x8000
+
+/* REG_TCR Bit fields */
+#define TCR_STANDARD_MODE	0x0000
+#define TCR_MASTER_WRITE	0x0000
+#define TCR_HS_MODE		0x2000
+#define TCR_MASTER_READ		0x4000
+#define TCR_FAST_MODE		0x8000
+#define TCR_SLAVE_ADDR_MASK	0x007F
+
+/* REG_ISR Bit fields */
+#define ISR_NACK_ADDR		0x0001
+#define ISR_BYTE_END		0x0002
+#define ISR_SCL_TIMEOUT		0x0004
+#define ISR_WRITE_ALL		0x0007
+
+/* REG_IMR Bit fields */
+#define IMR_ENABLE_ALL		0x0007
+
+/* REG_CSR Bit fields */
+#define CSR_RCV_NOT_ACK		0x0001
+#define CSR_RCV_ACK_MASK	0x0001
+#define CSR_READY_MASK		0x0002
+
+#define I2C_MODE_STANDARD	0
+#define I2C_MODE_FAST		1
+
+
+
+struct wmt_i2c_dev {
+	struct i2c_adapter	adapter;
+	struct completion	complete;
+	struct device		*dev;
+	void __iomem		*base;
+	struct clk		*clk;
+	int			mode;
+	int			irq;
+	u16			cmd_status;
+};
+
+static int wmt_i2c_wait_bus_not_busy(struct wmt_i2c_dev *i2c_dev)
+{
+	u16 val;
+	int i;
+	int ret = 0;
+
+	for (i = 0; i < 10000000; i++) {
+		val = readw(i2c_dev->base + REG_CSR);
+		if (val & CSR_READY_MASK)
+			break;
+
+		udelay(1);
+	}
+	if (i >= 9999999)
+		ret = -EBUSY;
+
+	return ret;
+}
+
+static int wmt_check_status(struct wmt_i2c_dev *i2c_dev)
+{
+	int ret = 0;
+
+	if (i2c_dev->cmd_status & ISR_NACK_ADDR)
+		ret = -EIO;
+
+	if (i2c_dev->cmd_status & ISR_SCL_TIMEOUT)
+		ret = -ETIMEDOUT;
+
+	return ret;
+}
+
+static int wmt_i2c_write(struct i2c_adapter *adap, struct i2c_msg *pmsg,
+						   int restart, int last)
+{
+	struct wmt_i2c_dev *i2c_dev = i2c_get_adapdata(adap);
+	u16 val;
+	u16 tcr_val;
+	int ret;
+	int wait_result;
+	u32 xfer_len = 0;
+
+	if (pmsg->len < 0)
+		return -EINVAL;
+
+	if (restart == 0) {
+		ret = wmt_i2c_wait_bus_not_busy(i2c_dev);
+		if (ret < 0)
+			return ret;
+	}
+
+	if (pmsg->len == 0)
+		writew(0, i2c_dev->base + REG_CDR);
+	else
+		writew(pmsg->buf[0] & 0xFF, i2c_dev->base + REG_CDR);
+
+	if (restart == 0) {
+		val = readw(i2c_dev->base + REG_CR);
+		val &= ~CR_TX_END;
+		writew(val, i2c_dev->base + REG_CR);
+
+		val = readw(i2c_dev->base + REG_CR);
+		val |= CR_CPU_RDY;
+		writew(val, i2c_dev->base + REG_CR);
+	}
+
+	init_completion(&i2c_dev->complete);
+
+	if (i2c_dev->mode == I2C_MODE_STANDARD)
+		tcr_val = TCR_STANDARD_MODE;
+	else
+		tcr_val = TCR_FAST_MODE;
+
+	tcr_val |= (TCR_MASTER_WRITE | (pmsg->addr & TCR_SLAVE_ADDR_MASK));
+
+	writew(tcr_val, i2c_dev->base + REG_TCR);
+
+	if (restart == 1) {
+		val = readw(i2c_dev->base + REG_CR);
+		val |= CR_CPU_RDY;
+		writew(val, i2c_dev->base + REG_CR);
+	}
+
+	ret = 0;
+
+	for (;;) {
+		wait_result = wait_for_completion_interruptible_timeout(
+				&i2c_dev->complete, 500 * HZ / 1000);
+
+		if (wait_result == 0) {
+			dev_dbg(i2c_dev->dev, "wait timeout (tx)\n");
+			ret = -ETIMEDOUT;
+			break;
+		}
+
+		ret = wmt_check_status(i2c_dev);
+		if (ret)
+			break;
+
+		xfer_len++;
+
+		val = readw(i2c_dev->base + REG_CSR);
+		if ((val & CSR_RCV_ACK_MASK) == CSR_RCV_NOT_ACK) {
+			dev_dbg(i2c_dev->dev, "write RCV NACK error\n");
+			ret = -EIO;
+			break;
+		}
+
+		if (pmsg->len == 0) {
+			val = CR_TX_END | CR_CPU_RDY | CR_ENABLE;
+			writew(val, i2c_dev->base + REG_CR);
+			break;
+		}
+
+		if (pmsg->len > xfer_len) {
+			writew(pmsg->buf[xfer_len] & 0xFF, i2c_dev->base +
+								REG_CDR);
+			writew(CR_CPU_RDY | CR_ENABLE, i2c_dev->base + REG_CR);
+		} else if (pmsg->len == xfer_len) {
+			if (last != 1)
+				writew(CR_ENABLE, i2c_dev->base + REG_CR);
+			break;
+		} else {
+			dev_dbg(i2c_dev->dev, "unknown error (tx)\n");
+			ret = -EIO;
+			break;
+		}
+	}
+
+	return ret;
+}
+
+static int wmt_i2c_read(struct i2c_adapter *adap, struct i2c_msg *pmsg,
+						  int restart, int last)
+{
+	struct wmt_i2c_dev *i2c_dev = i2c_get_adapdata(adap);
+	u16 val;
+	u16 tcr_val;
+	int ret;
+	int wait_result;
+	u32 xfer_len = 0;
+
+	if (pmsg->len <= 0)
+		return -EINVAL;
+
+	if (restart == 0) {
+		ret = wmt_i2c_wait_bus_not_busy(i2c_dev);
+		if (ret < 0)
+			return ret;
+	}
+
+	val = readw(i2c_dev->base + REG_CR);
+	val &= ~CR_TX_END;
+	writew(val, i2c_dev->base + REG_CR);
+
+	val = readw(i2c_dev->base + REG_CR);
+	val &= ~CR_TX_NEXT_NO_ACK;
+	writew(val, i2c_dev->base + REG_CR);
+
+	if (restart == 0) {
+		val = readw(i2c_dev->base + REG_CR);
+		val |= CR_CPU_RDY;
+		writew(val, i2c_dev->base + REG_CR);
+	}
+
+	if (pmsg->len == 1) {
+		val = readw(i2c_dev->base + REG_CR);
+		val |= CR_TX_NEXT_NO_ACK;
+		writew(val, i2c_dev->base + REG_CR);
+	}
+
+	init_completion(&i2c_dev->complete);
+
+	if (i2c_dev->mode == I2C_MODE_STANDARD)
+		tcr_val = TCR_STANDARD_MODE;
+	else
+		tcr_val = TCR_FAST_MODE;
+
+	tcr_val |= TCR_MASTER_READ | (pmsg->addr & TCR_SLAVE_ADDR_MASK);
+
+	writew(tcr_val, i2c_dev->base + REG_TCR);
+
+	if (restart == 1) {
+		val = readw(i2c_dev->base + REG_CR);
+		val |= CR_CPU_RDY;
+		writew(val, i2c_dev->base + REG_CR);
+	}
+
+	ret = 0;
+
+	for (;;) {
+		wait_result = wait_for_completion_interruptible_timeout(
+				&i2c_dev->complete, 500 * HZ / 1000);
+
+		if (wait_result == 0) {
+			dev_dbg(i2c_dev->dev, "wait timeout (tx)\n");
+			ret = -ETIMEDOUT;
+			break;
+		}
+
+		ret = wmt_check_status(i2c_dev);
+		if (ret)
+			break;
+
+		pmsg->buf[xfer_len] = readw(i2c_dev->base + REG_CDR) >> 8;
+		xfer_len++;
+
+		if (pmsg->len > xfer_len) {
+			if (pmsg->len - 1 == xfer_len) {
+				val = readw(i2c_dev->base + REG_CR);
+				val |= (CR_TX_NEXT_NO_ACK | CR_CPU_RDY);
+				writew(val, i2c_dev->base + REG_CR);
+			} else {
+				val = readw(i2c_dev->base + REG_CR);
+				val |= CR_CPU_RDY;
+				writew(val, i2c_dev->base + REG_CR);
+			}
+		} else if (pmsg->len == xfer_len) {
+			break;
+		} else {
+			ret = -EIO;
+			break;
+		}
+	}
+
+	return ret;
+}
+
+static int wmt_i2c_xfer(struct i2c_adapter *adap,
+			struct i2c_msg msgs[],
+			int num)
+{
+	struct i2c_msg *pmsg;
+	int i;
+	int ret = 0;
+	int is_last;
+	int restart;
+
+	for (i = 0; ret >= 0 && i < num; i++) {
+		is_last = ((i + 1) == num);
+		restart = (i != 0);
+
+		pmsg = &msgs[i];
+		if (pmsg->flags & I2C_M_NOSTART)
+			restart = 1;
+		if (pmsg->flags & I2C_M_RD)
+			ret = wmt_i2c_read(adap, pmsg, restart, is_last);
+		else
+			ret = wmt_i2c_write(adap, pmsg, restart, is_last);
+	}
+
+	if (ret < 0)
+		return ret;
+	else
+		return i;
+}
+
+static u32 wmt_i2c_func(struct i2c_adapter *adap)
+{
+	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
+}
+
+static const struct i2c_algorithm wmt_i2c_algo = {
+	.master_xfer	= wmt_i2c_xfer,
+	.functionality	= wmt_i2c_func,
+};
+
+static irqreturn_t wmt_i2c_isr(int irq, void *data)
+{
+	struct wmt_i2c_dev *i2c_dev = data;
+
+	/* save the status and write-clear it */
+	i2c_dev->cmd_status = readw(i2c_dev->base + REG_ISR);
+	writew(i2c_dev->cmd_status, i2c_dev->base + REG_ISR);
+
+	complete(&i2c_dev->complete);
+
+	return IRQ_HANDLED;
+}
+
+/*
+ * Due to a lack of pinmux functionality we need to manually configure
+ * the GPIO pullup. Once pinmux is implemented, this function should be
+ * removed. Pullup's are not available on vt8500 or wm8505 so we skip.
+ */
+static int wmt_i2c_setup_gpio(struct wmt_i2c_dev *i2c_dev)
+{
+	struct device_node *np;
+	void __iomem *gpio_base;
+	int nr = i2c_dev->adapter.nr;
+	u8 val;
+	u8 mask;
+
+	/* VT8500 - has external pullups so no configuration required. */
+	if (of_machine_is_compatible("via,vt8500"))
+		return 0;
+
+	/*
+	 * WM8505 - has external pullups but we need to config the alt func
+	 * WM8650 - has programmable pullups + alt func
+	 * WM8850 - has programmable pullups + alt func
+	 */
+	if (of_machine_is_compatible("wm,wm8505")) {
+		np = of_find_compatible_node(NULL, NULL, "wm,wm8505-gpio");
+		if (!np) {
+			dev_err(i2c_dev->dev, "GPIO required for WM8505 i2c\n");
+			return -EINVAL;
+		}
+	} else if (of_machine_is_compatible("wm,wm8650") ||
+		   of_machine_is_compatible("wm,wm8850")) {
+		np = of_find_compatible_node(NULL, NULL, "wm,wm8650-gpio");
+		if (!np) {
+			dev_err(i2c_dev->dev, "GPIO required for WM8650 i2c\n");
+			return -EINVAL;
+		}
+	} else {
+		/* If we don't know what machine, assume its configured */
+		dev_warn(i2c_dev->dev, "unrecognised machine\n");
+		return 0;
+	}
+
+	gpio_base = of_iomap(np, 0);
+	if (!gpio_base) {
+		dev_err(i2c_dev->dev, "failed to map gpio memory\n");
+		return -ENOMEM;
+	}
+
+	if (of_machine_is_compatible("wm,wm8505")) {
+		if (nr == 0) {
+			/* Set gpio pins to alt function */
+			val = readb(gpio_base + 0x500);
+			writeb(val & 0xFC, gpio_base + 0x500);
+		}
+	} else if (of_machine_is_compatible("wm,wm8650")) {
+		if (nr == 0) {
+			/* set gpio pins to alt function */
+			val = readb(gpio_base + 0x55);
+			val &= ~(BIT(0) | BIT(1));
+			writeb(val, gpio_base + 0x55);
+
+			/* enable pull */
+			val = readb(gpio_base + 0x495);
+			val |= (BIT(0) | BIT(1));
+			writeb(val, gpio_base + 0x495);
+
+			/* set pulled-up */
+			val = readb(gpio_base + 0x4D5);
+			val |= (BIT(0) | BIT(1));
+			writeb(val, gpio_base + 0x4D5);
+		} else if (nr == 1) {
+			/* set gpio pins to alt function */
+			val = readb(gpio_base + 0x49);
+			val &= ~(BIT(4) | BIT(5));
+			writeb(val, gpio_base + 0x49);
+
+			/* enable pull */
+			val = readb(gpio_base + 0x489);
+			val |= (BIT(4) | BIT(5));
+			writeb(val, gpio_base + 0x489);
+
+			/* set pulled-up */
+			val = readb(gpio_base + 0x4C9);
+			val |= (BIT(4) | BIT(5));
+			writeb(val, gpio_base + 0x4C9);
+		}
+	} else if (of_machine_is_compatible("wm,wm8850")) {
+		if ((nr >= 0) && (nr <= 2)) {
+			mask = 0x03 << (nr << 1);
+	
+			/* set gpio pins to alt function */
+			val = readb(gpio_base + 0x55);
+			val &= ~mask;
+			writeb(val, gpio_base + 0x55);
+
+			/* enable pull */
+			val = readb(gpio_base + 0x495);
+			val |= mask;
+			writeb(val, gpio_base + 0x495);
+
+			/* set pulled-up */
+			val = readb(gpio_base + 0x4D5);
+			val |= mask;
+			writeb(val, gpio_base + 0x4D5);
+		}
+	}
+
+
+	iounmap(gpio_base);
+
+	return 0;
+}
+
+static int wmt_i2c_reset_hardware(struct wmt_i2c_dev *i2c_dev)
+{
+	int err;
+
+	err = clk_prepare_enable(i2c_dev->clk);
+	if (err) {
+		dev_err(i2c_dev->dev, "failed to enable clock\n");
+		return err;
+	}
+
+	err = clk_set_rate(i2c_dev->clk, 20000000);
+	if (err) {
+		dev_err(i2c_dev->dev, "failed to set clock = 20Mhz\n");
+		return err;
+	}
+
+	err = wmt_i2c_setup_gpio(i2c_dev);
+	if (err)
+		return err;
+
+	writew(0, i2c_dev->base + REG_CR);
+	writew(12, i2c_dev->base + REG_MCR);
+	writew(ISR_WRITE_ALL, i2c_dev->base + REG_ISR);
+	writew(IMR_ENABLE_ALL, i2c_dev->base + REG_IMR);
+	writew(CR_ENABLE, i2c_dev->base + REG_CR);
+	readw(i2c_dev->base + REG_CSR);		/* read clear */
+	writew(ISR_WRITE_ALL, i2c_dev->base + REG_ISR);
+
+	if (i2c_dev->mode == I2C_MODE_STANDARD)
+		writew(0x8064, i2c_dev->base + REG_TR);
+	else
+		writew(0x8019, i2c_dev->base + REG_TR);
+
+	return 0;
+}
+
+static int wmt_i2c_probe(struct platform_device *pdev)
+{
+	struct device_node	*np = pdev->dev.of_node;
+	struct wmt_i2c_dev	*i2c_dev;
+	struct i2c_adapter	*adap;
+	struct resource		*res;
+	int err;
+	u32 clk_rate;
+
+	if (!np) {
+		dev_err(&pdev->dev, "device node not found\n");
+		return -ENODEV;
+	}
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!res) {
+		dev_err(&pdev->dev, "no memory resource defined\n");
+		return -ENODEV;
+	}
+
+	i2c_dev = devm_kzalloc(&pdev->dev, sizeof(*i2c_dev), GFP_KERNEL);
+	if (!i2c_dev) {
+		dev_err(&pdev->dev, "device memory allocation failed\n");
+		return -ENOMEM;
+	}
+
+	i2c_dev->base = devm_request_and_ioremap(&pdev->dev, res);
+	if (!i2c_dev->base) {
+		dev_err(&pdev->dev, "memory region unavailable\n");
+		return -ENOMEM;
+	}
+
+	i2c_dev->irq = irq_of_parse_and_map(np, 0);
+	if (!i2c_dev->irq) {
+		dev_err(&pdev->dev, "irq missing or invalid\n");
+		return -EINVAL;
+	}
+
+	i2c_dev->clk = of_clk_get(np, 0);
+	if (IS_ERR(i2c_dev->clk)) {
+		dev_err(&pdev->dev, "unable to request clock\n");
+		return PTR_ERR(i2c_dev->clk);
+	}
+
+	i2c_dev->mode = I2C_MODE_STANDARD;
+	err = of_property_read_u32(np, "clock-frequency", &clk_rate);
+	if ((!err) && (clk_rate == 400000))
+		i2c_dev->mode = I2C_MODE_FAST;
+
+	i2c_dev->dev = &pdev->dev;
+
+	err = devm_request_irq(&pdev->dev, i2c_dev->irq, wmt_i2c_isr, 0,
+							"i2c", i2c_dev);
+	if (err) {
+		dev_err(&pdev->dev, "failed to request irq %i\n", i2c_dev->irq);
+		return err;
+	}
+
+	adap = &i2c_dev->adapter;
+	i2c_set_adapdata(adap, i2c_dev);
+	strlcpy(adap->name, "WMT I2C adapter", sizeof(adap->name));
+	adap->owner		= THIS_MODULE;
+	adap->class		= I2C_CLASS_HWMON;
+	adap->algo		= &wmt_i2c_algo;
+	adap->dev.parent	= &pdev->dev;
+	adap->dev.of_node	= pdev->dev.of_node;
+	adap->nr		= of_alias_get_id(pdev->dev.of_node, "i2c");
+
+	err = wmt_i2c_reset_hardware(i2c_dev);
+	if (err) {
+		dev_err(&pdev->dev, "error initializing hardware\n");
+		return err;
+	}
+
+	if (adap->nr < 0)
+		err = i2c_add_adapter(adap);
+	else
+		err = i2c_add_numbered_adapter(adap);
+
+	if (err) {
+		dev_err(&pdev->dev, "failed to add adapter\n");
+		return err;
+	}
+
+	platform_set_drvdata(pdev, i2c_dev);
+
+	of_i2c_register_devices(adap);
+
+	return 0;
+}
+
+static int wmt_i2c_remove(struct platform_device *pdev)
+{
+	struct wmt_i2c_dev *i2c_dev = platform_get_drvdata(pdev);
+
+	i2c_del_adapter(&i2c_dev->adapter);
+
+	return 0;
+}
+
+static struct of_device_id wmt_i2c_dt_ids[] = {
+	{ .compatible = "wm,wm8505-i2c" },
+	{ /* Sentinel */ },
+};
+
+static struct platform_driver wmt_i2c_driver = {
+	.probe		= wmt_i2c_probe,
+	.remove		= wmt_i2c_remove,
+	.driver		= {
+		.name	= "wmt-i2c",
+		.owner	= THIS_MODULE,
+		.of_match_table = wmt_i2c_dt_ids,
+	},
+};
+
+module_platform_driver(wmt_i2c_driver);
+
+MODULE_DESCRIPTION("Wondermedia I2C master-mode bus adapter");
+MODULE_AUTHOR("Tony Prisk <linux@prisktech.co.nz>");
+MODULE_LICENSE("GPL v2");
+MODULE_DEVICE_TABLE(of, wmt_i2c_dt_ids);