diff mbox

[v2,1/4] iio: adc: add support for Berlin

Message ID 1428066409-30392-2-git-send-email-antoine.tenart@free-electrons.com (mailing list archive)
State New, archived
Headers show

Commit Message

Antoine Tenart April 3, 2015, 1:06 p.m. UTC 
This patch adds the support of the Berlin ADC, available on Berlin SoCs.
This ADC has 8 channels available, with one connected to a temperature
sensor.

The particularity here, is that the temperature sensor connected to the
ADC has its own registers, and both the ADC and the temperature sensor
must be configured when using it.

Signed-off-by: Antoine Tenart <antoine.tenart@free-electrons.com>
---
 drivers/iio/adc/Kconfig       |   7 +
 drivers/iio/adc/Makefile      |   1 +
 drivers/iio/adc/berlin2-adc.c | 379 ++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 387 insertions(+)
 create mode 100644 drivers/iio/adc/berlin2-adc.c

Comments

Jonathan Cameron April 9, 2015, 1:58 p.m. UTC | #1 
On 03/04/15 14:06, Antoine Tenart wrote:
> This patch adds the support of the Berlin ADC, available on Berlin SoCs.
> This ADC has 8 channels available, with one connected to a temperature
> sensor.
> 
> The particularity here, is that the temperature sensor connected to the
> ADC has its own registers, and both the ADC and the temperature sensor
> must be configured when using it.
> 
> Signed-off-by: Antoine Tenart <antoine.tenart@free-electrons.com>
Few bits and bobs inline.  However, big one is that you've gotten
confused on how the devm managed allocations work....
Also a lot of care is needed with using devm_iio_device_register.
It only makes sense in really simple devices where there really is nothing
to do on device removal...

> ---
>  drivers/iio/adc/Kconfig       |   7 +
>  drivers/iio/adc/Makefile      |   1 +
>  drivers/iio/adc/berlin2-adc.c | 379 ++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 387 insertions(+)
>  create mode 100644 drivers/iio/adc/berlin2-adc.c
> 
> diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
> index 202daf889be2..92cc40fd5e71 100644
> --- a/drivers/iio/adc/Kconfig
> +++ b/drivers/iio/adc/Kconfig
> @@ -135,6 +135,13 @@ config AXP288_ADC
>  	  device. Depending on platform configuration, this general purpose ADC can
>  	  be used for sampling sensors such as thermal resistors.
>  
> +config BERLIN2_ADC
> +	tristate "Marvell Berlin2 ADC driver"
> +	depends on ARCH_BERLIN
> +	help
> +	  Marvell Berlin2 ADC driver. This ADC has 8 channels, with one used for
> +	  temperature measurement.
> +
>  config CC10001_ADC
>  	tristate "Cosmic Circuits 10001 ADC driver"
>  	depends on HAS_IOMEM || HAVE_CLK || REGULATOR
> diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
> index 0315af640866..2b6dadaf7714 100644
> --- a/drivers/iio/adc/Makefile
> +++ b/drivers/iio/adc/Makefile
> @@ -15,6 +15,7 @@ obj-$(CONFIG_AD7887) += ad7887.o
>  obj-$(CONFIG_AD799X) += ad799x.o
>  obj-$(CONFIG_AT91_ADC) += at91_adc.o
>  obj-$(CONFIG_AXP288_ADC) += axp288_adc.o
> +obj-$(CONFIG_BERLIN2_ADC) += berlin2-adc.o
>  obj-$(CONFIG_CC10001_ADC) += cc10001_adc.o
>  obj-$(CONFIG_EXYNOS_ADC) += exynos_adc.o
>  obj-$(CONFIG_LP8788_ADC) += lp8788_adc.o
> diff --git a/drivers/iio/adc/berlin2-adc.c b/drivers/iio/adc/berlin2-adc.c
> new file mode 100644
> index 000000000000..cd21fefc403e
> --- /dev/null
> +++ b/drivers/iio/adc/berlin2-adc.c
> @@ -0,0 +1,379 @@
> +/*
> + * Marvell Berlin2 ADC driver
> + *
> + * Copyright (C) 2015 Marvell Technology Group Ltd.
> + *
> + * Antoine Tenart <antoine.tenart@free-electrons.com>
> + *
> + * This file is licensed under the terms of the GNU General Public
> + * License version 2. This program is licensed "as is" without any
> + * warranty of any kind, whether express or implied.
> + */
> +
> +#include <linux/iio/iio.h>
> +#include <linux/iio/driver.h>
> +#include <linux/iio/machine.h>
> +#include <linux/interrupt.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/slab.h>
> +#include <linux/mfd/syscon.h>
> +#include <linux/regmap.h>
> +#include <linux/sched.h>
> +#include <linux/wait.h>
> +
> +#define BERLIN2_SM_CTRL				0x14
> +#define  BERLIN2_SM_CTRL_SM_SOC_INT		BIT(1)
> +#define  BERLIN2_SM_CTRL_SOC_SM_INT		BIT(2)
> +#define  BERLIN2_SM_CTRL_ADC_SEL(x)		(BIT(x) << 5)	/* 0-15 */
> +#define  BERLIN2_SM_CTRL_ADC_SEL_MASK		(0xf << 5)
> +#define  BERLIN2_SM_CTRL_ADC_POWER		BIT(9)
> +#define  BERLIN2_SM_CTRL_ADC_CLKSEL_DIV2	(0x0 << 10)
> +#define  BERLIN2_SM_CTRL_ADC_CLKSEL_DIV3	(0x1 << 10)
> +#define  BERLIN2_SM_CTRL_ADC_CLKSEL_DIV4	(0x2 << 10)
> +#define  BERLIN2_SM_CTRL_ADC_CLKSEL_DIV8	(0x3 << 10)
> +#define  BERLIN2_SM_CTRL_ADC_CLKSEL_MASK	(0x3 << 10)
> +#define  BERLIN2_SM_CTRL_ADC_START		BIT(12)
> +#define  BERLIN2_SM_CTRL_ADC_RESET		BIT(13)
> +#define  BERLIN2_SM_CTRL_ADC_BANDGAP_RDY	BIT(14)
> +#define  BERLIN2_SM_CTRL_ADC_CONT_SINGLE	(0x0 << 15)
> +#define  BERLIN2_SM_CTRL_ADC_CONT_CONTINUOUS	(0x1 << 15)
> +#define  BERLIN2_SM_CTRL_ADC_BUFFER_EN		BIT(16)
> +#define  BERLIN2_SM_CTRL_ADC_VREF_EXT		(0x0 << 17)
> +#define  BERLIN2_SM_CTRL_ADC_VREF_INT		(0x1 << 17)
> +#define  BERLIN2_SM_CTRL_ADC_ROTATE		BIT(19)
> +#define  BERLIN2_SM_CTRL_TSEN_EN		BIT(20)
> +#define  BERLIN2_SM_CTRL_TSEN_CLK_SEL_125	(0x0 << 21)	/* 1.25 MHz */
> +#define  BERLIN2_SM_CTRL_TSEN_CLK_SEL_250	(0x1 << 21)	/* 2.5 MHz */
> +#define  BERLIN2_SM_CTRL_TSEN_MODE_0_125	(0x0 << 22)	/* 0-125 C */
> +#define  BERLIN2_SM_CTRL_TSEN_MODE_10_50	(0x1 << 22)	/* 10-50 C */
> +#define  BERLIN2_SM_CTRL_TSEN_RESET		BIT(29)
> +#define BERLIN2_SM_ADC_DATA			0x20
> +#define  BERLIN2_SM_ADC_MASK			0x3ff
> +#define BERLIN2_SM_ADC_STATUS			0x1c
> +#define  BERLIN2_SM_ADC_STATUS_DATA_RDY(x)	BIT(x)		/* 0-15 */
> +#define  BERLIN2_SM_ADC_STATUS_DATA_RDY_MASK	0xf
> +#define  BERLIN2_SM_ADC_STATUS_INT_EN(x)	(BIT(x) << 16)	/* 0-15 */
> +#define  BERLIN2_SM_ADC_STATUS_INT_EN_MASK	(0xf << 16)
> +#define BERLIN2_SM_TSEN_STATUS			0x24
> +#define  BERLIN2_SM_TSEN_STATUS_DATA_RDY	BIT(0)
> +#define  BERLIN2_SM_TSEN_STATUS_INT_EN		BIT(1)
> +#define BERLIN2_SM_TSEN_DATA			0x28
> +#define  BERLIN2_SM_TSEN_MASK			0xfff
> +#define BERLIN2_SM_TSEN_CTRL			0x74
> +#define  BERLIN2_SM_TSEN_CTRL_START		BIT(8)
> +#define  BERLIN2_SM_TSEN_CTRL_SETTLING_4	(0x0 << 21)	/* 4 us */
> +#define  BERLIN2_SM_TSEN_CTRL_SETTLING_12	(0x1 << 21)	/* 12 us */
> +#define  BERLIN2_SM_TSEN_CTRL_SETTLING_MASK	(0x1 << 21)
> +#define  BERLIN2_SM_TSEN_CTRL_TRIM(x)		((x) << 22)
> +#define  BERLIN2_SM_TSEN_CTRL_TRIM_MASK		(0xf << 22)
> +
> +struct berlin2_adc_priv {
> +	struct regmap		*regmap;
> +	struct mutex		lock;
> +	wait_queue_head_t	wq;
> +	int			irq;
> +	int			tsen_irq;
> +	bool			data_available;
> +	int			data;
> +};
> +
> +#define BERLIN2_ADC_CHANNEL(n, t)					\
> +		{							\
> +			.channel	= n,				\
> +			.datasheet_name	= "channel"#n,			\
> +			.type		= t,				\
> +			.indexed	= 1,				\
> +			.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),	\
> +		}
> +
> +static struct iio_chan_spec berlin2_adc_channels[] = {
> +	BERLIN2_ADC_CHANNEL(0, IIO_VOLTAGE),	/* external input */
> +	BERLIN2_ADC_CHANNEL(1, IIO_VOLTAGE),	/* external input */
> +	BERLIN2_ADC_CHANNEL(2, IIO_VOLTAGE),	/* external input */
> +	BERLIN2_ADC_CHANNEL(3, IIO_VOLTAGE),	/* external input */
> +	BERLIN2_ADC_CHANNEL(4, IIO_VOLTAGE),	/* reserved */
> +	BERLIN2_ADC_CHANNEL(5, IIO_VOLTAGE),	/* reserved */
> +	{					/* temperature sensor */
> +		.channel		= 6,
> +		.datasheet_name		= "channel6",
> +		.type			= IIO_TEMP,
> +		.indexed		= 0,
> +		.info_mask_separate	= BIT(IIO_CHAN_INFO_PROCESSED),
> +	},
> +	BERLIN2_ADC_CHANNEL(7, IIO_VOLTAGE),	/* reserved */
> +	IIO_CHAN_SOFT_TIMESTAMP(8),		/* timestamp */
> +};
> +#define BERLIN2_N_CHANNELS	ARRAY_SIZE(berlin2_adc_channels)
> +
> +static int berlin2_adc_read(struct iio_dev *indio_dev, int channel)
> +{
> +	struct berlin2_adc_priv *priv = iio_priv(indio_dev);
> +	int data, ret;
> +
> +	mutex_lock(&priv->lock);
> +
> +	/* Configure the ADC */
> +	regmap_update_bits(priv->regmap, BERLIN2_SM_CTRL,
> +			BERLIN2_SM_CTRL_ADC_RESET | BERLIN2_SM_CTRL_ADC_SEL_MASK
> +			| BERLIN2_SM_CTRL_ADC_START,
> +			BERLIN2_SM_CTRL_ADC_SEL(channel) | BERLIN2_SM_CTRL_ADC_START);
> +
> +	/* Enable the interrupts */
> +	regmap_write(priv->regmap, BERLIN2_SM_ADC_STATUS,
> +			BERLIN2_SM_ADC_STATUS_INT_EN(channel));
> +
> +	ret = wait_event_interruptible_timeout(priv->wq, priv->data_available,
> +			msecs_to_jiffies(1000));
> +
> +	/* Disable the interrupts */
> +	regmap_update_bits(priv->regmap, BERLIN2_SM_ADC_STATUS,
> +			BERLIN2_SM_ADC_STATUS_INT_EN(channel), 0);
> +
> +	if (ret == 0)
> +		ret = -ETIMEDOUT;
> +	if (ret < 0) {
> +		mutex_unlock(&priv->lock);
> +		return ret;
> +	}
> +
> +	regmap_update_bits(priv->regmap, BERLIN2_SM_CTRL,
> +			BERLIN2_SM_CTRL_ADC_START, 0);
> +
> +	data = priv->data;
> +	priv->data = -1;
> +	priv->data_available = false;
> +
> +	mutex_unlock(&priv->lock);
> +
> +	return data;
> +}
> +
> +static int berlin2_adc_tsen_read(struct iio_dev *indio_dev)
> +{
> +	struct berlin2_adc_priv *priv = iio_priv(indio_dev);
> +	int data, ret;
> +
> +	mutex_lock(&priv->lock);
> +
> +	/* Configure the ADC */
> +	regmap_update_bits(priv->regmap, BERLIN2_SM_CTRL,
> +			BERLIN2_SM_CTRL_TSEN_RESET | BERLIN2_SM_CTRL_ADC_ROTATE,
> +			BERLIN2_SM_CTRL_ADC_ROTATE);
> +
> +	/* Configure the temperature sensor */
> +	regmap_update_bits(priv->regmap, BERLIN2_SM_TSEN_CTRL,
> +			BERLIN2_SM_TSEN_CTRL_TRIM_MASK | BERLIN2_SM_TSEN_CTRL_SETTLING_MASK
> +			| BERLIN2_SM_TSEN_CTRL_START,
> +			BERLIN2_SM_TSEN_CTRL_TRIM(3) | BERLIN2_SM_TSEN_CTRL_SETTLING_12
> +			| BERLIN2_SM_TSEN_CTRL_START);
> +
> +	/* Enable interrupts */
> +	regmap_write(priv->regmap, BERLIN2_SM_TSEN_STATUS,
> +			BERLIN2_SM_TSEN_STATUS_INT_EN);
Is there a possible race here?  Depends on whether this is a level interrupt
or an edge triggered one... Would probably expect this just before the
call to start the read.
> +
> +	ret = wait_event_interruptible_timeout(priv->wq, priv->data_available,
> +			msecs_to_jiffies(1000));
> +
> +	/* Disable interrupts */
> +	regmap_update_bits(priv->regmap, BERLIN2_SM_TSEN_STATUS,
> +			BERLIN2_SM_TSEN_STATUS_INT_EN, 0);
> +
> +	if (ret == 0)
> +		ret = -ETIMEDOUT;
> +	if (ret < 0) {
> +		mutex_unlock(&priv->lock);
> +		return ret;
> +	}
> +
> +	regmap_update_bits(priv->regmap, BERLIN2_SM_TSEN_CTRL,
> +			BERLIN2_SM_TSEN_CTRL_START, 0);
> +
> +	data = priv->data;
> +	priv->data = -1;
> +	priv->data_available = false;
> +
> +	mutex_unlock(&priv->lock);
> +
> +	return data;
> +}
> +
> +static int berlin2_adc_read_raw(struct iio_dev *indio_dev,
> +		struct iio_chan_spec const *chan, int *val, int *val2,
> +		long mask)
> +{
> +	int temp;
> +
> +	switch (mask) {
> +	case IIO_CHAN_INFO_RAW:
> +		if (chan->type != IIO_VOLTAGE)
> +			return -EINVAL;
> +
> +		*val = berlin2_adc_read(indio_dev, chan->channel);
> +		if (*val < 0)
> +			return *val;
> +
> +		return IIO_VAL_INT;
> +	case IIO_CHAN_INFO_PROCESSED:
> +		if (chan->type != IIO_TEMP)
> +			return -EINVAL;
> +
> +		temp = berlin2_adc_tsen_read(indio_dev);
> +		if (temp < 0)
> +			return temp;
> +
> +		if (temp > 2047)
> +			temp = -(4096 - temp);
> +
> +		/* Convert to Celsius */
> +		*val = (temp * 100) / 264 - 270;
> +		return IIO_VAL_INT;
> +	default:
> +		break;
> +	}
> +
> +	return -EINVAL;
> +}
> +
> +static irqreturn_t berlin2_adc_irq(int irq, void *private)
> +{
> +	struct iio_dev *indio_dev = private;
> +	struct berlin2_adc_priv *priv = iio_priv(indio_dev);
> +	unsigned val;
> +
> +	regmap_read(priv->regmap, BERLIN2_SM_ADC_STATUS, &val);
> +	if (val & BERLIN2_SM_ADC_STATUS_DATA_RDY_MASK) {
> +		regmap_read(priv->regmap, BERLIN2_SM_ADC_DATA, &priv->data);
> +		priv->data &= BERLIN2_SM_ADC_MASK;
> +
> +		val &= ~BERLIN2_SM_ADC_STATUS_DATA_RDY_MASK;
> +		regmap_write(priv->regmap, BERLIN2_SM_ADC_STATUS, val);
> +
> +		priv->data_available = true;
> +		wake_up_interruptible(&priv->wq);
> +	}
> +
> +	return IRQ_HANDLED;
> +}
> +
> +static irqreturn_t berlin2_adc_tsen_irq(int irq, void *private)
> +{
> +	struct iio_dev *indio_dev = private;
> +	struct berlin2_adc_priv *priv = iio_priv(indio_dev);
I'd roll the above two lines into one.
struct berlin2_adc_priv *priv = iio_priv(private);

> +	unsigned val;
> +
> +	regmap_read(priv->regmap, BERLIN2_SM_TSEN_STATUS, &val);
> +	if (val & BERLIN2_SM_TSEN_STATUS_DATA_RDY) {
> +		regmap_read(priv->regmap, BERLIN2_SM_TSEN_DATA, &priv->data);
> +		priv->data &= BERLIN2_SM_TSEN_MASK;
> +
> +		val &= ~BERLIN2_SM_TSEN_STATUS_DATA_RDY;
> +		regmap_write(priv->regmap, BERLIN2_SM_TSEN_STATUS, val);
> +
> +		priv->data_available = true;
> +		wake_up_interruptible(&priv->wq);
> +	}
> +
> +	return IRQ_HANDLED;
> +}
> +
> +static const struct iio_info berlin2_adc_info = {
> +	.driver_module	= THIS_MODULE,
> +	.read_raw	= berlin2_adc_read_raw,
> +};
> +
> +static int berlin2_adc_probe(struct platform_device *pdev)
> +{
> +	struct iio_dev *indio_dev;
> +	struct berlin2_adc_priv *priv;
> +	struct device_node *parent_np = of_get_parent(pdev->dev.of_node);
> +	int ret;
> +
> +	indio_dev = devm_iio_device_alloc(&pdev->dev,
> +					  sizeof(struct berlin2_adc_priv));
> +	if (!indio_dev)
> +		return -ENOMEM;
> +
> +	priv = iio_priv(indio_dev);
> +	platform_set_drvdata(pdev, indio_dev);
> +
> +	priv->regmap = syscon_node_to_regmap(parent_np);
> +	of_node_put(parent_np);
> +	if (IS_ERR(priv->regmap))
> +		return PTR_ERR(priv->regmap);
> +
> +	priv->irq = platform_get_irq_byname(pdev, "adc");
> +	if (priv->irq < 0)
> +		return -ENODEV;
> +
> +	priv->tsen_irq = platform_get_irq_byname(pdev, "tsen");
> +	if (priv->tsen_irq < 0)
> +		return -ENODEV;
> +
> +	ret = devm_request_irq(&pdev->dev, priv->irq, berlin2_adc_irq, 0,
> +			pdev->dev.driver->name, indio_dev);
> +	if (ret)
> +		return ret;
> +
> +	ret = devm_request_irq(&pdev->dev, priv->tsen_irq, berlin2_adc_tsen_irq,
> +			0, pdev->dev.driver->name, indio_dev);
> +	if (ret)
> +		return ret;
> +
> +	init_waitqueue_head(&priv->wq);
> +	mutex_init(&priv->lock);
> +
> +	indio_dev->dev.parent = &pdev->dev;
> +	indio_dev->name = dev_name(&pdev->dev);
> +	indio_dev->modes = INDIO_DIRECT_MODE;
> +	indio_dev->info = &berlin2_adc_info;
> +
> +	indio_dev->num_channels = BERLIN2_N_CHANNELS;
> +	indio_dev->channels = berlin2_adc_channels;
> +
> +	/* Power up the ADC */
> +	regmap_update_bits(priv->regmap, BERLIN2_SM_CTRL,
> +			BERLIN2_SM_CTRL_ADC_POWER, BERLIN2_SM_CTRL_ADC_POWER);
> +
> +	return devm_iio_device_register(&pdev->dev, indio_dev);
you are mixing devm requests with explicit removes in the remove.
You are going to get double frees.

You'll also want to catch any errors from iio_device_register and power down
the device (via the regmap call) if the register fails.

> +}
> +
> +static int berlin2_adc_remove(struct platform_device *pdev)
> +{
> +	struct iio_dev *indio_dev = platform_get_drvdata(pdev);
> +	struct berlin2_adc_priv *priv = iio_priv(indio_dev);
> +
> +	iio_device_unregister(indio_dev);
As you used devm_iio_device_register you don't need to explicitly unregister.
However...
> +
> +	/* Power down the ADC */
> +	regmap_update_bits(priv->regmap, BERLIN2_SM_CTRL,
> +			BERLIN2_SM_CTRL_ADC_POWER, 0);
If you do use the devm register above then the userspace access to the
hardware will only be removed AFTER the regmap_update_bits here. Hence
there will be a nasty window.  I would suggest not using the
devm_iio_device_register but rather iio_device_register and then keep
the explicit unregister here.

> +
> +	free_irq(priv->irq, indio_dev);
> +	free_irq(priv->tsen_irq, indio_dev);
> +
> +	iio_device_free(indio_dev);
You used devm versions of the irq requests and iio_device alloc.  These
frees should not be here and will result in a double free.
> +
> +	return 0;
> +}
> +
> +static const struct of_device_id berlin2_adc_match[] = {
> +	{ .compatible = "marvell,berlin2-adc", },
> +	{ },
> +};
> +MODULE_DEVICE_TABLE(of, berlin2q_adc_match);
> +
> +static struct platform_driver berlin2_adc_driver = {
> +	.driver	= {
> +		.name		= "berlin2-adc",
> +		.of_match_table	= berlin2_adc_match,
> +	},
> +	.probe	= berlin2_adc_probe,
> +	.remove	= berlin2_adc_remove,
> +};
> +module_platform_driver(berlin2_adc_driver);
> +
> +MODULE_AUTHOR("Antoine Tenart <antoine.tenart@free-electrons.com>");
> +MODULE_DESCRIPTION("Marvell Berlin2 ADC driver");
> +MODULE_LICENSE("GPL v2");
>
diff mbox

Patch

diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
index 202daf889be2..92cc40fd5e71 100644
--- a/drivers/iio/adc/Kconfig
+++ b/drivers/iio/adc/Kconfig
@@ -135,6 +135,13 @@  config AXP288_ADC
 	  device. Depending on platform configuration, this general purpose ADC can
 	  be used for sampling sensors such as thermal resistors.
 
+config BERLIN2_ADC
+	tristate "Marvell Berlin2 ADC driver"
+	depends on ARCH_BERLIN
+	help
+	  Marvell Berlin2 ADC driver. This ADC has 8 channels, with one used for
+	  temperature measurement.
+
 config CC10001_ADC
 	tristate "Cosmic Circuits 10001 ADC driver"
 	depends on HAS_IOMEM || HAVE_CLK || REGULATOR
diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
index 0315af640866..2b6dadaf7714 100644
--- a/drivers/iio/adc/Makefile
+++ b/drivers/iio/adc/Makefile
@@ -15,6 +15,7 @@  obj-$(CONFIG_AD7887) += ad7887.o
 obj-$(CONFIG_AD799X) += ad799x.o
 obj-$(CONFIG_AT91_ADC) += at91_adc.o
 obj-$(CONFIG_AXP288_ADC) += axp288_adc.o
+obj-$(CONFIG_BERLIN2_ADC) += berlin2-adc.o
 obj-$(CONFIG_CC10001_ADC) += cc10001_adc.o
 obj-$(CONFIG_EXYNOS_ADC) += exynos_adc.o
 obj-$(CONFIG_LP8788_ADC) += lp8788_adc.o
diff --git a/drivers/iio/adc/berlin2-adc.c b/drivers/iio/adc/berlin2-adc.c
new file mode 100644
index 000000000000..cd21fefc403e
--- /dev/null
+++ b/drivers/iio/adc/berlin2-adc.c
@@ -0,0 +1,379 @@ 
+/*
+ * Marvell Berlin2 ADC driver
+ *
+ * Copyright (C) 2015 Marvell Technology Group Ltd.
+ *
+ * Antoine Tenart <antoine.tenart@free-electrons.com>
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2. This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+
+#include <linux/iio/iio.h>
+#include <linux/iio/driver.h>
+#include <linux/iio/machine.h>
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/mfd/syscon.h>
+#include <linux/regmap.h>
+#include <linux/sched.h>
+#include <linux/wait.h>
+
+#define BERLIN2_SM_CTRL				0x14
+#define  BERLIN2_SM_CTRL_SM_SOC_INT		BIT(1)
+#define  BERLIN2_SM_CTRL_SOC_SM_INT		BIT(2)
+#define  BERLIN2_SM_CTRL_ADC_SEL(x)		(BIT(x) << 5)	/* 0-15 */
+#define  BERLIN2_SM_CTRL_ADC_SEL_MASK		(0xf << 5)
+#define  BERLIN2_SM_CTRL_ADC_POWER		BIT(9)
+#define  BERLIN2_SM_CTRL_ADC_CLKSEL_DIV2	(0x0 << 10)
+#define  BERLIN2_SM_CTRL_ADC_CLKSEL_DIV3	(0x1 << 10)
+#define  BERLIN2_SM_CTRL_ADC_CLKSEL_DIV4	(0x2 << 10)
+#define  BERLIN2_SM_CTRL_ADC_CLKSEL_DIV8	(0x3 << 10)
+#define  BERLIN2_SM_CTRL_ADC_CLKSEL_MASK	(0x3 << 10)
+#define  BERLIN2_SM_CTRL_ADC_START		BIT(12)
+#define  BERLIN2_SM_CTRL_ADC_RESET		BIT(13)
+#define  BERLIN2_SM_CTRL_ADC_BANDGAP_RDY	BIT(14)
+#define  BERLIN2_SM_CTRL_ADC_CONT_SINGLE	(0x0 << 15)
+#define  BERLIN2_SM_CTRL_ADC_CONT_CONTINUOUS	(0x1 << 15)
+#define  BERLIN2_SM_CTRL_ADC_BUFFER_EN		BIT(16)
+#define  BERLIN2_SM_CTRL_ADC_VREF_EXT		(0x0 << 17)
+#define  BERLIN2_SM_CTRL_ADC_VREF_INT		(0x1 << 17)
+#define  BERLIN2_SM_CTRL_ADC_ROTATE		BIT(19)
+#define  BERLIN2_SM_CTRL_TSEN_EN		BIT(20)
+#define  BERLIN2_SM_CTRL_TSEN_CLK_SEL_125	(0x0 << 21)	/* 1.25 MHz */
+#define  BERLIN2_SM_CTRL_TSEN_CLK_SEL_250	(0x1 << 21)	/* 2.5 MHz */
+#define  BERLIN2_SM_CTRL_TSEN_MODE_0_125	(0x0 << 22)	/* 0-125 C */
+#define  BERLIN2_SM_CTRL_TSEN_MODE_10_50	(0x1 << 22)	/* 10-50 C */
+#define  BERLIN2_SM_CTRL_TSEN_RESET		BIT(29)
+#define BERLIN2_SM_ADC_DATA			0x20
+#define  BERLIN2_SM_ADC_MASK			0x3ff
+#define BERLIN2_SM_ADC_STATUS			0x1c
+#define  BERLIN2_SM_ADC_STATUS_DATA_RDY(x)	BIT(x)		/* 0-15 */
+#define  BERLIN2_SM_ADC_STATUS_DATA_RDY_MASK	0xf
+#define  BERLIN2_SM_ADC_STATUS_INT_EN(x)	(BIT(x) << 16)	/* 0-15 */
+#define  BERLIN2_SM_ADC_STATUS_INT_EN_MASK	(0xf << 16)
+#define BERLIN2_SM_TSEN_STATUS			0x24
+#define  BERLIN2_SM_TSEN_STATUS_DATA_RDY	BIT(0)
+#define  BERLIN2_SM_TSEN_STATUS_INT_EN		BIT(1)
+#define BERLIN2_SM_TSEN_DATA			0x28
+#define  BERLIN2_SM_TSEN_MASK			0xfff
+#define BERLIN2_SM_TSEN_CTRL			0x74
+#define  BERLIN2_SM_TSEN_CTRL_START		BIT(8)
+#define  BERLIN2_SM_TSEN_CTRL_SETTLING_4	(0x0 << 21)	/* 4 us */
+#define  BERLIN2_SM_TSEN_CTRL_SETTLING_12	(0x1 << 21)	/* 12 us */
+#define  BERLIN2_SM_TSEN_CTRL_SETTLING_MASK	(0x1 << 21)
+#define  BERLIN2_SM_TSEN_CTRL_TRIM(x)		((x) << 22)
+#define  BERLIN2_SM_TSEN_CTRL_TRIM_MASK		(0xf << 22)
+
+struct berlin2_adc_priv {
+	struct regmap		*regmap;
+	struct mutex		lock;
+	wait_queue_head_t	wq;
+	int			irq;
+	int			tsen_irq;
+	bool			data_available;
+	int			data;
+};
+
+#define BERLIN2_ADC_CHANNEL(n, t)					\
+		{							\
+			.channel	= n,				\
+			.datasheet_name	= "channel"#n,			\
+			.type		= t,				\
+			.indexed	= 1,				\
+			.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),	\
+		}
+
+static struct iio_chan_spec berlin2_adc_channels[] = {
+	BERLIN2_ADC_CHANNEL(0, IIO_VOLTAGE),	/* external input */
+	BERLIN2_ADC_CHANNEL(1, IIO_VOLTAGE),	/* external input */
+	BERLIN2_ADC_CHANNEL(2, IIO_VOLTAGE),	/* external input */
+	BERLIN2_ADC_CHANNEL(3, IIO_VOLTAGE),	/* external input */
+	BERLIN2_ADC_CHANNEL(4, IIO_VOLTAGE),	/* reserved */
+	BERLIN2_ADC_CHANNEL(5, IIO_VOLTAGE),	/* reserved */
+	{					/* temperature sensor */
+		.channel		= 6,
+		.datasheet_name		= "channel6",
+		.type			= IIO_TEMP,
+		.indexed		= 0,
+		.info_mask_separate	= BIT(IIO_CHAN_INFO_PROCESSED),
+	},
+	BERLIN2_ADC_CHANNEL(7, IIO_VOLTAGE),	/* reserved */
+	IIO_CHAN_SOFT_TIMESTAMP(8),		/* timestamp */
+};
+#define BERLIN2_N_CHANNELS	ARRAY_SIZE(berlin2_adc_channels)
+
+static int berlin2_adc_read(struct iio_dev *indio_dev, int channel)
+{
+	struct berlin2_adc_priv *priv = iio_priv(indio_dev);
+	int data, ret;
+
+	mutex_lock(&priv->lock);
+
+	/* Configure the ADC */
+	regmap_update_bits(priv->regmap, BERLIN2_SM_CTRL,
+			BERLIN2_SM_CTRL_ADC_RESET | BERLIN2_SM_CTRL_ADC_SEL_MASK
+			| BERLIN2_SM_CTRL_ADC_START,
+			BERLIN2_SM_CTRL_ADC_SEL(channel) | BERLIN2_SM_CTRL_ADC_START);
+
+	/* Enable the interrupts */
+	regmap_write(priv->regmap, BERLIN2_SM_ADC_STATUS,
+			BERLIN2_SM_ADC_STATUS_INT_EN(channel));
+
+	ret = wait_event_interruptible_timeout(priv->wq, priv->data_available,
+			msecs_to_jiffies(1000));
+
+	/* Disable the interrupts */
+	regmap_update_bits(priv->regmap, BERLIN2_SM_ADC_STATUS,
+			BERLIN2_SM_ADC_STATUS_INT_EN(channel), 0);
+
+	if (ret == 0)
+		ret = -ETIMEDOUT;
+	if (ret < 0) {
+		mutex_unlock(&priv->lock);
+		return ret;
+	}
+
+	regmap_update_bits(priv->regmap, BERLIN2_SM_CTRL,
+			BERLIN2_SM_CTRL_ADC_START, 0);
+
+	data = priv->data;
+	priv->data = -1;
+	priv->data_available = false;
+
+	mutex_unlock(&priv->lock);
+
+	return data;
+}
+
+static int berlin2_adc_tsen_read(struct iio_dev *indio_dev)
+{
+	struct berlin2_adc_priv *priv = iio_priv(indio_dev);
+	int data, ret;
+
+	mutex_lock(&priv->lock);
+
+	/* Configure the ADC */
+	regmap_update_bits(priv->regmap, BERLIN2_SM_CTRL,
+			BERLIN2_SM_CTRL_TSEN_RESET | BERLIN2_SM_CTRL_ADC_ROTATE,
+			BERLIN2_SM_CTRL_ADC_ROTATE);
+
+	/* Configure the temperature sensor */
+	regmap_update_bits(priv->regmap, BERLIN2_SM_TSEN_CTRL,
+			BERLIN2_SM_TSEN_CTRL_TRIM_MASK | BERLIN2_SM_TSEN_CTRL_SETTLING_MASK
+			| BERLIN2_SM_TSEN_CTRL_START,
+			BERLIN2_SM_TSEN_CTRL_TRIM(3) | BERLIN2_SM_TSEN_CTRL_SETTLING_12
+			| BERLIN2_SM_TSEN_CTRL_START);
+
+	/* Enable interrupts */
+	regmap_write(priv->regmap, BERLIN2_SM_TSEN_STATUS,
+			BERLIN2_SM_TSEN_STATUS_INT_EN);
+
+	ret = wait_event_interruptible_timeout(priv->wq, priv->data_available,
+			msecs_to_jiffies(1000));
+
+	/* Disable interrupts */
+	regmap_update_bits(priv->regmap, BERLIN2_SM_TSEN_STATUS,
+			BERLIN2_SM_TSEN_STATUS_INT_EN, 0);
+
+	if (ret == 0)
+		ret = -ETIMEDOUT;
+	if (ret < 0) {
+		mutex_unlock(&priv->lock);
+		return ret;
+	}
+
+	regmap_update_bits(priv->regmap, BERLIN2_SM_TSEN_CTRL,
+			BERLIN2_SM_TSEN_CTRL_START, 0);
+
+	data = priv->data;
+	priv->data = -1;
+	priv->data_available = false;
+
+	mutex_unlock(&priv->lock);
+
+	return data;
+}
+
+static int berlin2_adc_read_raw(struct iio_dev *indio_dev,
+		struct iio_chan_spec const *chan, int *val, int *val2,
+		long mask)
+{
+	int temp;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		if (chan->type != IIO_VOLTAGE)
+			return -EINVAL;
+
+		*val = berlin2_adc_read(indio_dev, chan->channel);
+		if (*val < 0)
+			return *val;
+
+		return IIO_VAL_INT;
+	case IIO_CHAN_INFO_PROCESSED:
+		if (chan->type != IIO_TEMP)
+			return -EINVAL;
+
+		temp = berlin2_adc_tsen_read(indio_dev);
+		if (temp < 0)
+			return temp;
+
+		if (temp > 2047)
+			temp = -(4096 - temp);
+
+		/* Convert to Celsius */
+		*val = (temp * 100) / 264 - 270;
+		return IIO_VAL_INT;
+	default:
+		break;
+	}
+
+	return -EINVAL;
+}
+
+static irqreturn_t berlin2_adc_irq(int irq, void *private)
+{
+	struct iio_dev *indio_dev = private;
+	struct berlin2_adc_priv *priv = iio_priv(indio_dev);
+	unsigned val;
+
+	regmap_read(priv->regmap, BERLIN2_SM_ADC_STATUS, &val);
+	if (val & BERLIN2_SM_ADC_STATUS_DATA_RDY_MASK) {
+		regmap_read(priv->regmap, BERLIN2_SM_ADC_DATA, &priv->data);
+		priv->data &= BERLIN2_SM_ADC_MASK;
+
+		val &= ~BERLIN2_SM_ADC_STATUS_DATA_RDY_MASK;
+		regmap_write(priv->regmap, BERLIN2_SM_ADC_STATUS, val);
+
+		priv->data_available = true;
+		wake_up_interruptible(&priv->wq);
+	}
+
+	return IRQ_HANDLED;
+}
+
+static irqreturn_t berlin2_adc_tsen_irq(int irq, void *private)
+{
+	struct iio_dev *indio_dev = private;
+	struct berlin2_adc_priv *priv = iio_priv(indio_dev);
+	unsigned val;
+
+	regmap_read(priv->regmap, BERLIN2_SM_TSEN_STATUS, &val);
+	if (val & BERLIN2_SM_TSEN_STATUS_DATA_RDY) {
+		regmap_read(priv->regmap, BERLIN2_SM_TSEN_DATA, &priv->data);
+		priv->data &= BERLIN2_SM_TSEN_MASK;
+
+		val &= ~BERLIN2_SM_TSEN_STATUS_DATA_RDY;
+		regmap_write(priv->regmap, BERLIN2_SM_TSEN_STATUS, val);
+
+		priv->data_available = true;
+		wake_up_interruptible(&priv->wq);
+	}
+
+	return IRQ_HANDLED;
+}
+
+static const struct iio_info berlin2_adc_info = {
+	.driver_module	= THIS_MODULE,
+	.read_raw	= berlin2_adc_read_raw,
+};
+
+static int berlin2_adc_probe(struct platform_device *pdev)
+{
+	struct iio_dev *indio_dev;
+	struct berlin2_adc_priv *priv;
+	struct device_node *parent_np = of_get_parent(pdev->dev.of_node);
+	int ret;
+
+	indio_dev = devm_iio_device_alloc(&pdev->dev,
+					  sizeof(struct berlin2_adc_priv));
+	if (!indio_dev)
+		return -ENOMEM;
+
+	priv = iio_priv(indio_dev);
+	platform_set_drvdata(pdev, indio_dev);
+
+	priv->regmap = syscon_node_to_regmap(parent_np);
+	of_node_put(parent_np);
+	if (IS_ERR(priv->regmap))
+		return PTR_ERR(priv->regmap);
+
+	priv->irq = platform_get_irq_byname(pdev, "adc");
+	if (priv->irq < 0)
+		return -ENODEV;
+
+	priv->tsen_irq = platform_get_irq_byname(pdev, "tsen");
+	if (priv->tsen_irq < 0)
+		return -ENODEV;
+
+	ret = devm_request_irq(&pdev->dev, priv->irq, berlin2_adc_irq, 0,
+			pdev->dev.driver->name, indio_dev);
+	if (ret)
+		return ret;
+
+	ret = devm_request_irq(&pdev->dev, priv->tsen_irq, berlin2_adc_tsen_irq,
+			0, pdev->dev.driver->name, indio_dev);
+	if (ret)
+		return ret;
+
+	init_waitqueue_head(&priv->wq);
+	mutex_init(&priv->lock);
+
+	indio_dev->dev.parent = &pdev->dev;
+	indio_dev->name = dev_name(&pdev->dev);
+	indio_dev->modes = INDIO_DIRECT_MODE;
+	indio_dev->info = &berlin2_adc_info;
+
+	indio_dev->num_channels = BERLIN2_N_CHANNELS;
+	indio_dev->channels = berlin2_adc_channels;
+
+	/* Power up the ADC */
+	regmap_update_bits(priv->regmap, BERLIN2_SM_CTRL,
+			BERLIN2_SM_CTRL_ADC_POWER, BERLIN2_SM_CTRL_ADC_POWER);
+
+	return devm_iio_device_register(&pdev->dev, indio_dev);
+}
+
+static int berlin2_adc_remove(struct platform_device *pdev)
+{
+	struct iio_dev *indio_dev = platform_get_drvdata(pdev);
+	struct berlin2_adc_priv *priv = iio_priv(indio_dev);
+
+	iio_device_unregister(indio_dev);
+
+	/* Power down the ADC */
+	regmap_update_bits(priv->regmap, BERLIN2_SM_CTRL,
+			BERLIN2_SM_CTRL_ADC_POWER, 0);
+
+	free_irq(priv->irq, indio_dev);
+	free_irq(priv->tsen_irq, indio_dev);
+
+	iio_device_free(indio_dev);
+
+	return 0;
+}
+
+static const struct of_device_id berlin2_adc_match[] = {
+	{ .compatible = "marvell,berlin2-adc", },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, berlin2q_adc_match);
+
+static struct platform_driver berlin2_adc_driver = {
+	.driver	= {
+		.name		= "berlin2-adc",
+		.of_match_table	= berlin2_adc_match,
+	},
+	.probe	= berlin2_adc_probe,
+	.remove	= berlin2_adc_remove,
+};
+module_platform_driver(berlin2_adc_driver);
+
+MODULE_AUTHOR("Antoine Tenart <antoine.tenart@free-electrons.com>");
+MODULE_DESCRIPTION("Marvell Berlin2 ADC driver");
+MODULE_LICENSE("GPL v2");