[v2,2/3] auxadc: Add Mediatek auxadc driver for mt2701.
diff mbox

Message ID 1467690610-20550-3-git-send-email-zhiyong.tao@mediatek.com
State New
Headers show

Commit Message

Zhiyong Tao July 5, 2016, 3:50 a.m. UTC
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

Comments

Peter Meerwald-Stadler July 5, 2016, 8:15 a.m. UTC | #1
> 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.

comments below
 
> 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

not strictly alphabethic

>  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 */

Register definitions

> +#define MT65XX_AUXADC_CON0                    0x00

usually the prefix matches the driver name

> +#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;

why are the delays stored in the struct, you could use the #defines above 
directly?

> +};
> +
> +#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;

I'd use -ETIMEDOUT

> +	}
> +
> +	/* 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;

I suggest to return *val and not change the error code

> +		}
> +		ret = IIO_VAL_INT;

return IIO_VAL_INT seems simpler

> +		break;
> +	default:

return -EINVAL ...

> +		ret = -EINVAL;
> +		break;
> +	}
> +

... and drop next line

> +	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");

need to power off and unprepare clock here
> +		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");
>

Patch
diff mbox

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");