[PATCH v2 0/3] AUXADC: Mediatek auxadc driver

[PATCH v2 0/3] AUXADC: Mediatek auxadc driver

[Zhiyong Tao]

This series includes three patches:
1.Change the device tree binding documentation.
2.Add auxadc driver based on linux iio.
3.Add auxadc nodes in the mediatek MT2701 dtsi file.

changes in patch 2:
1).Change the file name mt65xx_auxadc.c to mt6577_auxadc.c.
2).Add 'depends on ARCH_MEDIATEK || COMPILE_TEST and HAS_IOMEM' for MEDIATEK_MT65XX_AUXADC config.
3).Add check case for return value of 'readl_poll_timeout'.
4).Remove returning 1 and 0 for SCALE and OFFSET. use channel type 'IIO_CHAN_INFO_PROCESSED' instead of 'IIO_CHAN_INFO_RAW'.
5).Remove 'IIO_CHAN_INFO_OFFSET' and 'IIO_CHAN_INFO_SCALE' in 'MT65XX_AUXADC_CHANNEL' channel type.
6).Add check case when auxadc power on failure. if auxadc power on failure, clk_disable_unprepare should be executed.
7).Put 'platform_set_drvdata' before 'iio_device_register'.
8).Fix coding style and spelling error.

Zhiyong Tao (3):
  dt-bindings: auxadc: Add binding document for Mediatek auxadc.
  auxadc: Add Mediatek auxadc driver for mt2701.
  arm: dts: auxadc: Add auxadc node.

 .../devicetree/bindings/iio/adc/mt65xx_auxadc.txt  |   27 ++
 .../devicetree/bindings/soc/mediatek/auxadc.txt    |   21 --
 arch/arm/boot/dts/mt2701.dtsi                      |    9 +
 drivers/iio/adc/Kconfig                            |   13 +
 drivers/iio/adc/Makefile                           |    1 +
 drivers/iio/adc/mt6577_auxadc.c                    |  301 ++++++++++++++++++++
 6 files changed, 351 insertions(+), 21 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/iio/adc/mt65xx_auxadc.txt
 delete mode 100644 Documentation/devicetree/bindings/soc/mediatek/auxadc.txt
 create mode 100644 drivers/iio/adc/mt6577_auxadc.c

[PATCH v2 1/3] dt-bindings: auxadc: Add binding document for Mediatek auxadc.

[Zhiyong Tao]

The commit adds the device tree binding documentation for the mediatek
auxadc found on Mediatek MT2701.
Thermal gets auxadc sample data by iio device.
So the commit changes auxadc device tree binding documentation from
/soc/mediatek/auxadc.txt to /iio/adc/mt65xx_auxadc.txt.

Signed-off-by: Zhiyong Tao <zhiyong.tao-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org>
---
 .../devicetree/bindings/iio/adc/mt65xx_auxadc.txt  |   27 ++++++++++++++++++++
 .../devicetree/bindings/soc/mediatek/auxadc.txt    |   21 ---------------
 2 files changed, 27 insertions(+), 21 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/iio/adc/mt65xx_auxadc.txt
 delete mode 100644 Documentation/devicetree/bindings/soc/mediatek/auxadc.txt

diff --git a/Documentation/devicetree/bindings/iio/adc/mt65xx_auxadc.txt b/Documentation/devicetree/bindings/iio/adc/mt65xx_auxadc.txt
new file mode 100644
index 0000000..47fcd1b
--- /dev/null
+++ b/Documentation/devicetree/bindings/iio/adc/mt65xx_auxadc.txt
@@ -0,0 +1,27 @@
+* Mediatek AUXADC - Analog to Digital Converter on Mediatek mobile soc (mt65xx/mt81xx/mt27xx)
+===============
+
+The Auxiliary Analog/Digital Converter (AUXADC) is an ADC found
+in some Mediatek SoCs which among other things measures the temperatures
+in the SoC. It can be used directly with register accesses, but it is also
+used by thermal controller which reads the temperatures from the AUXADC
+directly via its own bus interface. See
+Documentation/devicetree/bindings/thermal/mediatek-thermal.txt
+for the Thermal Controller which holds a phandle to the AUXADC.
+
+Required properties:
+  - compatible: "mediatek,mt2701-auxadc" or "mediatek,mt8173-auxadc"
+  - reg: Address range of the AUXADC unit.
+  - clocks: Should contain a clock specifier for each entry in clock-names
+  - clock-names: Should contain "main".
+  - io-channel-cells: Should be 1, see ../iio-bindings.txt
+
+Example:
+
+auxadc: auxadc@11001000 {
+	compatible = "mediatek,mt2701-auxadc";
+	reg = <0 0x11001000 0 0x1000>;
+	clocks = <&pericfg CLK_PERI_AUXADC>;
+	clock-names = "main";
+	#io-channel-cells = <1>;
+};
diff --git a/Documentation/devicetree/bindings/soc/mediatek/auxadc.txt b/Documentation/devicetree/bindings/soc/mediatek/auxadc.txt
deleted file mode 100644
index bdb7829..0000000
--- a/Documentation/devicetree/bindings/soc/mediatek/auxadc.txt
+++ /dev/null
@@ -1,21 +0,0 @@
-MediaTek AUXADC
-===============
-
-The Auxiliary Analog/Digital Converter (AUXADC) is an ADC found
-in some Mediatek SoCs which among other things measures the temperatures
-in the SoC. It can be used directly with register accesses, but it is also
-used by thermal controller which reads the temperatures from the AUXADC
-directly via its own bus interface. See
-Documentation/devicetree/bindings/thermal/mediatek-thermal.txt
-for the Thermal Controller which holds a phandle to the AUXADC.
-
-Required properties:
-- compatible: Must be "mediatek,mt8173-auxadc"
-- reg: Address range of the AUXADC unit
-
-Example:
-
-auxadc: auxadc@11001000 {
-	compatible = "mediatek,mt8173-auxadc";
-	reg = <0 0x11001000 0 0x1000>;
-};
-- 
1.7.9.5

Re: [PATCH v2 1/3] dt-bindings: auxadc: Add binding document for Mediatek auxadc.

[Rob Herring]

On Tue, Jul 05, 2016 at 11:50:08AM +0800, Zhiyong Tao wrote:
> The commit adds the device tree binding documentation for the mediatek
> auxadc found on Mediatek MT2701.
> Thermal gets auxadc sample data by iio device.
> So the commit changes auxadc device tree binding documentation from
> /soc/mediatek/auxadc.txt to /iio/adc/mt65xx_auxadc.txt.
> 
> Signed-off-by: Zhiyong Tao <zhiyong.tao-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org>
> ---
>  .../devicetree/bindings/iio/adc/mt65xx_auxadc.txt  |   27 ++++++++++++++++++++
>  .../devicetree/bindings/soc/mediatek/auxadc.txt    |   21 ---------------
>  2 files changed, 27 insertions(+), 21 deletions(-)
>  create mode 100644 Documentation/devicetree/bindings/iio/adc/mt65xx_auxadc.txt
>  delete mode 100644 Documentation/devicetree/bindings/soc/mediatek/auxadc.txt

Next time, use the git-format-patch -M option to send so only the 
changes have to be reviewed.

> 
> diff --git a/Documentation/devicetree/bindings/iio/adc/mt65xx_auxadc.txt b/Documentation/devicetree/bindings/iio/adc/mt65xx_auxadc.txt
> new file mode 100644
> index 0000000..47fcd1b
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/iio/adc/mt65xx_auxadc.txt
> @@ -0,0 +1,27 @@
> +* Mediatek AUXADC - Analog to Digital Converter on Mediatek mobile soc (mt65xx/mt81xx/mt27xx)
> +===============
> +
> +The Auxiliary Analog/Digital Converter (AUXADC) is an ADC found
> +in some Mediatek SoCs which among other things measures the temperatures
> +in the SoC. It can be used directly with register accesses, but it is also
> +used by thermal controller which reads the temperatures from the AUXADC
> +directly via its own bus interface. See
> +Documentation/devicetree/bindings/thermal/mediatek-thermal.txt
> +for the Thermal Controller which holds a phandle to the AUXADC.
> +
> +Required properties:
> +  - compatible: "mediatek,mt2701-auxadc" or "mediatek,mt8173-auxadc"
> +  - reg: Address range of the AUXADC unit.
> +  - clocks: Should contain a clock specifier for each entry in clock-names
> +  - clock-names: Should contain "main".
> +  - io-channel-cells: Should be 1, see ../iio-bindings.txt

Should be #io-channel-cells

> +
> +Example:
> +
> +auxadc: auxadc@11001000 {

Should be adc@...

> +	compatible = "mediatek,mt2701-auxadc";
> +	reg = <0 0x11001000 0 0x1000>;
> +	clocks = <&pericfg CLK_PERI_AUXADC>;
> +	clock-names = "main";
> +	#io-channel-cells = <1>;
> +};
> diff --git a/Documentation/devicetree/bindings/soc/mediatek/auxadc.txt b/Documentation/devicetree/bindings/soc/mediatek/auxadc.txt
> deleted file mode 100644
> index bdb7829..0000000
> --- a/Documentation/devicetree/bindings/soc/mediatek/auxadc.txt
> +++ /dev/null
> @@ -1,21 +0,0 @@
> -MediaTek AUXADC
> -===============
> -
> -The Auxiliary Analog/Digital Converter (AUXADC) is an ADC found
> -in some Mediatek SoCs which among other things measures the temperatures
> -in the SoC. It can be used directly with register accesses, but it is also
> -used by thermal controller which reads the temperatures from the AUXADC
> -directly via its own bus interface. See
> -Documentation/devicetree/bindings/thermal/mediatek-thermal.txt
> -for the Thermal Controller which holds a phandle to the AUXADC.
> -
> -Required properties:
> -- compatible: Must be "mediatek,mt8173-auxadc"
> -- reg: Address range of the AUXADC unit
> -
> -Example:
> -
> -auxadc: auxadc@11001000 {
> -	compatible = "mediatek,mt8173-auxadc";
> -	reg = <0 0x11001000 0 0x1000>;
> -};
> -- 
> 1.7.9.5
> 
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[PATCH v2 3/3] arm: dts: auxadc: Add auxadc node.

[Zhiyong Tao]

The commit adds auxadc nodes to the Mediatek MT2701 dtsi file.

Signed-off-by: Zhiyong Tao <zhiyong.tao-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org>
---
 arch/arm/boot/dts/mt2701.dtsi |    9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/arch/arm/boot/dts/mt2701.dtsi b/arch/arm/boot/dts/mt2701.dtsi
index 42d5a37..464c86a 100644
--- a/arch/arm/boot/dts/mt2701.dtsi
+++ b/arch/arm/boot/dts/mt2701.dtsi
@@ -187,6 +187,15 @@
 		      <0 0x10216000 0 0x2000>;
 	};
 
+	auxadc: auxadc@11001000 {
+		compatible = "mediatek,mt2701-auxadc";
+		reg = <0 0x11001000 0 0x1000>;
+		clocks = <&pericfg CLK_PERI_AUXADC>;
+		clock-names = "main";
+		#io-channel-cells = <1>;
+		status = "disabled";
+	};
+
 	uart0: serial@11002000 {
 		compatible = "mediatek,mt2701-uart",
 			     "mediatek,mt6577-uart";
-- 
1.7.9.5

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[PATCH v2 2/3] auxadc: Add Mediatek auxadc driver for mt2701.

[Zhiyong Tao]

Add Mediatek auxadc driver based on iio.
It will register a device in iio and support iio.
So thermal can read auxadc channel to sample data by iio device.
It is tested successfully on mt2701 platform.
Mt8173 and mt6577 platforms are not tested.
But the expectation is compatible.

Signed-off-by: Zhiyong Tao <zhiyong.tao@mediatek.com>
---
 drivers/iio/adc/Kconfig         |   13 ++
 drivers/iio/adc/Makefile        |    1 +
 drivers/iio/adc/mt6577_auxadc.c |  301 +++++++++++++++++++++++++++++++++++++++
 3 files changed, 315 insertions(+)
 create mode 100644 drivers/iio/adc/mt6577_auxadc.c

diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
index 25378c5..66e9b44 100644
--- a/drivers/iio/adc/Kconfig
+++ b/drivers/iio/adc/Kconfig
@@ -315,6 +315,19 @@ config MEN_Z188_ADC
 	  This driver can also be built as a module. If so, the module will be
 	  called men_z188_adc.
 
+config MEDIATEK_MT65XX_AUXADC
+	tristate "MediaTek AUXADC driver"
+	depends on ARCH_MEDIATEK || COMPILE_TEST
+	depends on HAS_IOMEM
+	help
+	  Say yes here to enable support for MediaTek mt65xx AUXADC.
+
+	  The driver supports immediate mode operation to read from one of sixteen
+	  channels (external or internal).
+
+	  This driver can also be built as a module. If so, the module will be
+	  called mt6577_auxadc.
+
 config MXS_LRADC
         tristate "Freescale i.MX23/i.MX28 LRADC"
         depends on (ARCH_MXS || COMPILE_TEST) && HAS_IOMEM
diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
index 38638d4..14a630f 100644
--- a/drivers/iio/adc/Makefile
+++ b/drivers/iio/adc/Makefile
@@ -31,6 +31,7 @@ obj-$(CONFIG_MAX1363) += max1363.o
 obj-$(CONFIG_MCP320X) += mcp320x.o
 obj-$(CONFIG_MCP3422) += mcp3422.o
 obj-$(CONFIG_MEN_Z188_ADC) += men_z188_adc.o
+obj-$(CONFIG_MEDIATEK_MT65XX_AUXADC) += mt6577_auxadc.o
 obj-$(CONFIG_MXS_LRADC) += mxs-lradc.o
 obj-$(CONFIG_NAU7802) += nau7802.o
 obj-$(CONFIG_PALMAS_GPADC) += palmas_gpadc.o
diff --git a/drivers/iio/adc/mt6577_auxadc.c b/drivers/iio/adc/mt6577_auxadc.c
new file mode 100644
index 0000000..a56531a
--- /dev/null
+++ b/drivers/iio/adc/mt6577_auxadc.c
@@ -0,0 +1,301 @@
+/*
+ * Copyright (c) 2016 MediaTek Inc.
+ * Author: Zhiyong Tao <zhiyong.tao@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/delay.h>
+#include <linux/err.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/iopoll.h>
+#include <linux/io.h>
+#include <linux/iio/iio.h>
+
+/* Registers definitions */
+#define MT65XX_AUXADC_CON0                    0x00
+#define MT65XX_AUXADC_CON1                    0x04
+#define MT65XX_AUXADC_CON2                    0x10
+#define MT65XX_AUXADC_STA                     BIT(0)
+
+#define MT65XX_AUXADC_DAT0                    0x14
+#define MT65XX_AUXADC_RDY0                    BIT(12)
+
+#define MT65XX_AUXADC_MISC                    0x94
+#define MT65XX_AUXADC_PDN_EN                  BIT(14)
+
+#define MT65XX_AUXADC_DAT_MASK                0xfff
+#define MT65XX_AUXADC_SLEEP_US                1000
+#define MT65XX_AUXADC_TIMEOUT_US              10000
+#define MT65XX_AUXADC_POWER_READY_MS          1
+#define MT65XX_AUXADC_SAMPLE_READY_US         25
+
+struct mt65xx_auxadc_device {
+	void __iomem *reg_base;
+	struct clk *adc_clk;
+	struct mutex lock;
+	unsigned int power_ready_ms;
+	unsigned int sample_ready_us;
+};
+
+#define MT65XX_AUXADC_CHANNEL(idx) {				    \
+		.type = IIO_VOLTAGE,				    \
+		.indexed = 1,					    \
+		.channel = (idx),				    \
+		.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED), \
+}
+
+static const struct iio_chan_spec mt65xx_auxadc_iio_channels[] = {
+	MT65XX_AUXADC_CHANNEL(0),
+	MT65XX_AUXADC_CHANNEL(1),
+	MT65XX_AUXADC_CHANNEL(2),
+	MT65XX_AUXADC_CHANNEL(3),
+	MT65XX_AUXADC_CHANNEL(4),
+	MT65XX_AUXADC_CHANNEL(5),
+	MT65XX_AUXADC_CHANNEL(6),
+	MT65XX_AUXADC_CHANNEL(7),
+	MT65XX_AUXADC_CHANNEL(8),
+	MT65XX_AUXADC_CHANNEL(9),
+	MT65XX_AUXADC_CHANNEL(10),
+	MT65XX_AUXADC_CHANNEL(11),
+	MT65XX_AUXADC_CHANNEL(12),
+	MT65XX_AUXADC_CHANNEL(13),
+	MT65XX_AUXADC_CHANNEL(14),
+	MT65XX_AUXADC_CHANNEL(15),
+};
+
+static int mt65xx_auxadc_read(struct iio_dev *indio_dev,
+			      struct iio_chan_spec const *chan)
+{
+	u32 rawdata, val;
+	void __iomem *reg_channel;
+	int ret;
+	struct mt65xx_auxadc_device *adc_dev = iio_priv(indio_dev);
+
+	reg_channel = adc_dev->reg_base + MT65XX_AUXADC_DAT0 +
+		      chan->channel * 0x04;
+
+	mutex_lock(&adc_dev->lock);
+
+	val = readl(adc_dev->reg_base + MT65XX_AUXADC_CON1);
+	val &= ~(1 << chan->channel);
+	writel(val, adc_dev->reg_base + MT65XX_AUXADC_CON1);
+
+	/* read channel and make sure old ready bit == 0 */
+	ret = readl_poll_timeout(reg_channel, val,
+				 ((val & MT65XX_AUXADC_RDY0) == 0),
+				 MT65XX_AUXADC_SLEEP_US,
+				 MT65XX_AUXADC_TIMEOUT_US);
+	if (ret < 0) {
+		dev_err(indio_dev->dev.parent,
+			"wait for channel[%d] ready bit clear time out\n",
+			chan->channel);
+
+		mutex_unlock(&adc_dev->lock);
+
+		return -EINVAL;
+	}
+
+	/* set bit to trigger sample */
+	val = readl(adc_dev->reg_base + MT65XX_AUXADC_CON1);
+	val |= 1 << chan->channel;
+	writel(val, adc_dev->reg_base + MT65XX_AUXADC_CON1);
+
+	/* we must delay here for hardware sample channel data */
+	udelay(adc_dev->sample_ready_us);
+
+	/* check MTK_AUXADC_CON2 if auxadc is idle */
+	ret = readl_poll_timeout(adc_dev->reg_base + MT65XX_AUXADC_CON2, val,
+				 ((val & MT65XX_AUXADC_STA) == 0),
+				 MT65XX_AUXADC_SLEEP_US,
+				 MT65XX_AUXADC_TIMEOUT_US);
+	if (ret < 0) {
+		dev_err(indio_dev->dev.parent,
+			"wait for auxadc idle time out\n");
+
+		mutex_unlock(&adc_dev->lock);
+
+		return -EINVAL;
+	}
+
+	/* read channel and make sure ready bit == 1 */
+	ret = readl_poll_timeout(reg_channel, val,
+				 ((val & MT65XX_AUXADC_RDY0) != 0),
+				 MT65XX_AUXADC_SLEEP_US,
+				 MT65XX_AUXADC_TIMEOUT_US);
+	if (ret < 0) {
+		dev_err(indio_dev->dev.parent,
+			"wait for channel[%d] data ready time out\n",
+			chan->channel);
+
+		mutex_unlock(&adc_dev->lock);
+
+		return -EINVAL;
+	}
+
+	/* read data */
+	rawdata = readl(reg_channel) & MT65XX_AUXADC_DAT_MASK;
+
+	mutex_unlock(&adc_dev->lock);
+
+	return rawdata;
+}
+
+static int mt65xx_auxadc_read_raw(struct iio_dev *indio_dev,
+				  struct iio_chan_spec const *chan,
+				  int *val,
+				  int *val2,
+				  long info)
+{
+	int ret;
+
+	switch (info) {
+	case IIO_CHAN_INFO_PROCESSED:
+		*val = mt65xx_auxadc_read(indio_dev, chan);
+		if (*val < 0) {
+			dev_err(indio_dev->dev.parent,
+				"failed to sample data on channel[%d]\n",
+				chan->channel);
+			return -EIO;
+		}
+		ret = IIO_VAL_INT;
+		break;
+	default:
+		ret = -EINVAL;
+		break;
+	}
+
+	return ret;
+}
+
+static const struct iio_info mt65xx_auxadc_info = {
+	.driver_module = THIS_MODULE,
+	.read_raw = &mt65xx_auxadc_read_raw,
+};
+
+static int mt65xx_auxadc_probe(struct platform_device *pdev)
+{
+	struct mt65xx_auxadc_device *adc_dev;
+	unsigned long adc_clk_rate;
+	struct resource *res;
+	struct iio_dev *indio_dev;
+	int ret;
+	u32 val;
+
+	indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*adc_dev));
+	if (!indio_dev)
+		return -ENOMEM;
+
+	adc_dev = iio_priv(indio_dev);
+	indio_dev->dev.parent = &pdev->dev;
+	indio_dev->name = dev_name(&pdev->dev);
+	indio_dev->info = &mt65xx_auxadc_info;
+	indio_dev->modes = INDIO_DIRECT_MODE;
+	indio_dev->channels = mt65xx_auxadc_iio_channels;
+	indio_dev->num_channels = ARRAY_SIZE(mt65xx_auxadc_iio_channels);
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	adc_dev->reg_base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(adc_dev->reg_base)) {
+		dev_err(&pdev->dev, "failed to get auxadc base address.\n");
+		return PTR_ERR(adc_dev->reg_base);
+	}
+
+	adc_dev->adc_clk = devm_clk_get(&pdev->dev, "main");
+	if (IS_ERR(adc_dev->adc_clk)) {
+		dev_err(&pdev->dev, "failed to get auxadc clock\n");
+		return PTR_ERR(adc_dev->adc_clk);
+	}
+
+	ret = clk_prepare_enable(adc_dev->adc_clk);
+	if (ret) {
+		dev_err(&pdev->dev, "failed to enable auxadc clock\n");
+		return ret;
+	}
+
+	adc_clk_rate = clk_get_rate(adc_dev->adc_clk);
+	if (!adc_clk_rate) {
+		dev_err(&pdev->dev, "null clock rate!\n");
+		goto err_disable_clk;
+	}
+
+	adc_dev->power_ready_ms = MT65XX_AUXADC_POWER_READY_MS;
+	adc_dev->sample_ready_us = MT65XX_AUXADC_SAMPLE_READY_US;
+
+	mutex_init(&adc_dev->lock);
+
+	val = readl(adc_dev->reg_base + MT65XX_AUXADC_MISC);
+	val |= MT65XX_AUXADC_PDN_EN;
+	writel(val, adc_dev->reg_base + MT65XX_AUXADC_MISC);
+	mdelay(adc_dev->power_ready_ms);
+
+	val = readl(adc_dev->reg_base + MT65XX_AUXADC_MISC);
+	if ((val & MT65XX_AUXADC_PDN_EN) == 0) {
+		dev_err(&pdev->dev, "failed to enable auxadc power!\n");
+		goto err_disable_clk;
+	}
+
+	platform_set_drvdata(pdev, indio_dev);
+
+	ret = iio_device_register(indio_dev);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "failed to register iio device!\n");
+		return ret;
+	}
+
+	return 0;
+
+err_disable_clk:
+	clk_disable_unprepare(adc_dev->adc_clk);
+	return -EINVAL;
+}
+
+static int mt65xx_auxadc_remove(struct platform_device *pdev)
+{
+	struct iio_dev *indio_dev = platform_get_drvdata(pdev);
+	struct mt65xx_auxadc_device *adc_dev = iio_priv(indio_dev);
+	u32 val;
+
+	iio_device_unregister(indio_dev);
+
+	val = readl(adc_dev->reg_base + MT65XX_AUXADC_MISC);
+	val &= ~MT65XX_AUXADC_PDN_EN;
+	writel(val, adc_dev->reg_base + MT65XX_AUXADC_MISC);
+
+	clk_disable_unprepare(adc_dev->adc_clk);
+
+	return 0;
+}
+
+static const struct of_device_id mt65xx_auxadc_of_match[] = {
+	{ .compatible = "mediatek,mt2701-auxadc", },
+	{ .compatible = "mediatek,mt8173-auxadc", },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, mt65xx_auxadc_of_match);
+
+static struct platform_driver mt65xx_auxadc_driver = {
+	.driver = {
+		.name   = "mt65xx-auxadc",
+		.of_match_table = mt65xx_auxadc_of_match,
+	},
+	.probe	= mt65xx_auxadc_probe,
+	.remove	= mt65xx_auxadc_remove,
+};
+module_platform_driver(mt65xx_auxadc_driver);
+
+MODULE_AUTHOR("Zhiyong Tao <zhiyong.tao@mediatek.com>");
+MODULE_DESCRIPTION("MTK AUXADC Device Driver");
+MODULE_LICENSE("GPL v2");
-- 
1.7.9.5