Message-ID: <0530c4e7-c902-1246-79a4-34be9831c3e5@kernel.org>
Date:	Sun, 3 Jul 2016 11:33:39 +0100
From:	Jonathan Cameron <jic23@...nel.org>
To:	Raveendra Padasalagi <raveendra.padasalagi@...adcom.com>,
	Peter Meerwald-Stadler <pmeerw@...erw.net>,
	Rob Herring <robh+dt@...nel.org>,
	Russell King <linux@....linux.org.uk>,
	Arnd Bergmann <arnd@...db.de>, linux-iio@...r.kernel.org,
	devicetree@...r.kernel.org, linux-arm-kernel@...ts.infradead.org
Cc:	Pawel Moll <pawel.moll@....com>,
	Mark Rutland <mark.rutland@....com>,
	Ian Campbell <ijc+devicetree@...lion.org.uk>,
	Kumar Gala <galak@...eaurora.org>,
	Jonathan Richardson <jonathar@...adcom.com>,
	Jon Mason <jonmason@...adcom.com>,
	Florian Fainelli <f.fainelli@...il.com>,
	Anup Patel <anup.patel@...adcom.com>,
	Ray Jui <rjui@...adcom.com>,
	Scott Branden <sbranden@...adcom.com>,
	Pramod Kumar <pramod.kumar@...adcom.com>,
	linux-kernel@...r.kernel.org, bcm-kernel-feedback-list@...adcom.com
Subject: Re: [PATCH v4 2/3] iio: Add driver for Broadcom iproc-static-adc

On 28/06/16 08:40, Raveendra Padasalagi wrote:
> This patch adds basic driver implementation for Broadcom's
> static adc controller used in iProc SoC's family.
> 
> Signed-off-by: Raveendra Padasalagi <raveendra.padasalagi@...adcom.com>
> Reviewed-by: Ray Jui <ray.jui@...adcom.com>
> Reviewed-by: Scott Branden <scott.branden@...adcom.com>
Looks good to me.

Applied to the togreg branch of iio.git -- initially pushed out as
testing for the autobuilders to play with it.

Thanks,

Jonathan
> ---
>  drivers/iio/adc/Kconfig         |  12 +
>  drivers/iio/adc/Makefile        |   1 +
>  drivers/iio/adc/bcm_iproc_adc.c | 644 ++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 657 insertions(+)
>  create mode 100644 drivers/iio/adc/bcm_iproc_adc.c
> 
> diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
> index 25378c5..1de31bd 100644
> --- a/drivers/iio/adc/Kconfig
> +++ b/drivers/iio/adc/Kconfig
> @@ -153,6 +153,18 @@ config AXP288_ADC
>  	  To compile this driver as a module, choose M here: the module will be
>  	  called axp288_adc.
>  
> +config BCM_IPROC_ADC
> +	tristate "Broadcom IPROC ADC driver"
> +	depends on ARCH_BCM_IPROC || COMPILE_TEST
> +	depends on MFD_SYSCON
> +	default ARCH_BCM_CYGNUS
> +	help
> +	  Say Y here if you want to add support for the Broadcom static
> +	  ADC driver.
> +
> +	  Broadcom iProc ADC driver. Broadcom iProc ADC controller has 8
> +	  channels. The driver allows the user to read voltage values.
> +
>  config BERLIN2_ADC
>  	tristate "Marvell Berlin2 ADC driver"
>  	depends on ARCH_BERLIN
> diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
> index 38638d4..0ba0d50 100644
> --- a/drivers/iio/adc/Makefile
> +++ b/drivers/iio/adc/Makefile
> @@ -16,6 +16,7 @@ obj-$(CONFIG_AD799X) += ad799x.o
>  obj-$(CONFIG_AT91_ADC) += at91_adc.o
>  obj-$(CONFIG_AT91_SAMA5D2_ADC) += at91-sama5d2_adc.o
>  obj-$(CONFIG_AXP288_ADC) += axp288_adc.o
> +obj-$(CONFIG_BCM_IPROC_ADC) += bcm_iproc_adc.o
>  obj-$(CONFIG_BERLIN2_ADC) += berlin2-adc.o
>  obj-$(CONFIG_CC10001_ADC) += cc10001_adc.o
>  obj-$(CONFIG_DA9150_GPADC) += da9150-gpadc.o
> diff --git a/drivers/iio/adc/bcm_iproc_adc.c b/drivers/iio/adc/bcm_iproc_adc.c
> new file mode 100644
> index 0000000..21d38c8
> --- /dev/null
> +++ b/drivers/iio/adc/bcm_iproc_adc.c
> @@ -0,0 +1,644 @@
> +/*
> + * Copyright 2016 Broadcom
> + *
> + * 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 (the "GPL").
> + *
> + * 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 version 2 (GPLv2) for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * version 2 (GPLv2) along with this source code.
> + */
> +
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/io.h>
> +#include <linux/clk.h>
> +#include <linux/mfd/syscon.h>
> +#include <linux/regmap.h>
> +#include <linux/delay.h>
> +#include <linux/interrupt.h>
> +#include <linux/platform_device.h>
> +
> +#include <linux/iio/iio.h>
> +
> +/* Below Register's are common to IPROC ADC and Touchscreen IP */
> +#define IPROC_REGCTL1			0x00
> +#define IPROC_REGCTL2			0x04
> +#define IPROC_INTERRUPT_THRES		0x08
> +#define IPROC_INTERRUPT_MASK		0x0c
> +#define IPROC_INTERRUPT_STATUS		0x10
> +#define IPROC_ANALOG_CONTROL		0x1c
> +#define IPROC_CONTROLLER_STATUS		0x14
> +#define IPROC_AUX_DATA			0x20
> +#define IPROC_SOFT_BYPASS_CONTROL	0x38
> +#define IPROC_SOFT_BYPASS_DATA		0x3C
> +
> +/* IPROC ADC Channel register offsets */
> +#define IPROC_ADC_CHANNEL_REGCTL1		0x800
> +#define IPROC_ADC_CHANNEL_REGCTL2		0x804
> +#define IPROC_ADC_CHANNEL_STATUS		0x808
> +#define IPROC_ADC_CHANNEL_INTERRUPT_STATUS	0x80c
> +#define IPROC_ADC_CHANNEL_INTERRUPT_MASK	0x810
> +#define IPROC_ADC_CHANNEL_DATA			0x814
> +#define IPROC_ADC_CHANNEL_OFFSET		0x20
> +
> +/* Bit definitions for IPROC_REGCTL2 */
> +#define IPROC_ADC_AUXIN_SCAN_ENA	BIT(0)
> +#define IPROC_ADC_PWR_LDO		BIT(5)
> +#define IPROC_ADC_PWR_ADC		BIT(4)
> +#define IPROC_ADC_PWR_BG		BIT(3)
> +#define IPROC_ADC_CONTROLLER_EN		BIT(17)
> +
> +/* Bit definitions for IPROC_INTERRUPT_MASK and IPROC_INTERRUPT_STATUS */
> +#define IPROC_ADC_AUXDATA_RDY_INTR	BIT(3)
> +#define IPROC_ADC_INTR			9
> +#define IPROC_ADC_INTR_MASK		(0xFF << IPROC_ADC_INTR)
> +
> +/* Bit definitions for IPROC_ANALOG_CONTROL */
> +#define IPROC_ADC_CHANNEL_SEL		11
> +#define IPROC_ADC_CHANNEL_SEL_MASK	(0x7 << IPROC_ADC_CHANNEL_SEL)
> +
> +/* Bit definitions for IPROC_ADC_CHANNEL_REGCTL1 */
> +#define IPROC_ADC_CHANNEL_ROUNDS	0x2
> +#define IPROC_ADC_CHANNEL_ROUNDS_MASK	(0x3F << IPROC_ADC_CHANNEL_ROUNDS)
> +#define IPROC_ADC_CHANNEL_MODE		0x1
> +#define IPROC_ADC_CHANNEL_MODE_MASK	(0x1 << IPROC_ADC_CHANNEL_MODE)
> +#define IPROC_ADC_CHANNEL_MODE_TDM	0x1
> +#define IPROC_ADC_CHANNEL_MODE_SNAPSHOT 0x0
> +#define IPROC_ADC_CHANNEL_ENABLE	0x0
> +#define IPROC_ADC_CHANNEL_ENABLE_MASK	0x1
> +
> +/* Bit definitions for IPROC_ADC_CHANNEL_REGCTL2 */
> +#define IPROC_ADC_CHANNEL_WATERMARK	0x0
> +#define IPROC_ADC_CHANNEL_WATERMARK_MASK \
> +		(0x3F << IPROC_ADC_CHANNEL_WATERMARK)
> +
> +#define IPROC_ADC_WATER_MARK_LEVEL	0x1
> +
> +/* Bit definitions for IPROC_ADC_CHANNEL_STATUS */
> +#define IPROC_ADC_CHANNEL_DATA_LOST		0x0
> +#define IPROC_ADC_CHANNEL_DATA_LOST_MASK	\
> +		(0x0 << IPROC_ADC_CHANNEL_DATA_LOST)
> +#define IPROC_ADC_CHANNEL_VALID_ENTERIES	0x1
> +#define IPROC_ADC_CHANNEL_VALID_ENTERIES_MASK	\
> +		(0xFF << IPROC_ADC_CHANNEL_VALID_ENTERIES)
> +#define IPROC_ADC_CHANNEL_TOTAL_ENTERIES	0x9
> +#define IPROC_ADC_CHANNEL_TOTAL_ENTERIES_MASK	\
> +		(0xFF << IPROC_ADC_CHANNEL_TOTAL_ENTERIES)
> +
> +/* Bit definitions for IPROC_ADC_CHANNEL_INTERRUPT_MASK */
> +#define IPROC_ADC_CHANNEL_WTRMRK_INTR			0x0
> +#define IPROC_ADC_CHANNEL_WTRMRK_INTR_MASK		\
> +		(0x1 << IPROC_ADC_CHANNEL_WTRMRK_INTR)
> +#define IPROC_ADC_CHANNEL_FULL_INTR			0x1
> +#define IPROC_ADC_CHANNEL_FULL_INTR_MASK		\
> +		(0x1 << IPROC_ADC_IPROC_ADC_CHANNEL_FULL_INTR)
> +#define IPROC_ADC_CHANNEL_EMPTY_INTR			0x2
> +#define IPROC_ADC_CHANNEL_EMPTY_INTR_MASK		\
> +		(0x1 << IPROC_ADC_CHANNEL_EMPTY_INTR)
> +
> +#define IPROC_ADC_WATER_MARK_INTR_ENABLE		0x1
> +
> +/* Number of time to retry a set of the interrupt mask reg */
> +#define IPROC_ADC_INTMASK_RETRY_ATTEMPTS		10
> +
> +#define IPROC_ADC_READ_TIMEOUT        (HZ*2)
> +
> +#define iproc_adc_dbg_reg(dev, priv, reg) \
> +do { \
> +	u32 val; \
> +	regmap_read(priv->regmap, reg, &val); \
> +	dev_dbg(dev, "%20s= 0x%08x\n", #reg, val); \
> +} while (0)
> +
> +struct iproc_adc_priv {
> +	struct regmap *regmap;
> +	struct clk *adc_clk;
> +	struct mutex mutex;
> +	int  irqno;
> +	int chan_val;
> +	int chan_id;
> +	struct completion completion;
> +};
> +
> +static void iproc_adc_reg_dump(struct iio_dev *indio_dev)
> +{
> +	struct device *dev = &indio_dev->dev;
> +	struct iproc_adc_priv *adc_priv = iio_priv(indio_dev);
> +
> +	iproc_adc_dbg_reg(dev, adc_priv, IPROC_REGCTL1);
> +	iproc_adc_dbg_reg(dev, adc_priv, IPROC_REGCTL2);
> +	iproc_adc_dbg_reg(dev, adc_priv, IPROC_INTERRUPT_THRES);
> +	iproc_adc_dbg_reg(dev, adc_priv, IPROC_INTERRUPT_MASK);
> +	iproc_adc_dbg_reg(dev, adc_priv, IPROC_INTERRUPT_STATUS);
> +	iproc_adc_dbg_reg(dev, adc_priv, IPROC_CONTROLLER_STATUS);
> +	iproc_adc_dbg_reg(dev, adc_priv, IPROC_ANALOG_CONTROL);
> +	iproc_adc_dbg_reg(dev, adc_priv, IPROC_AUX_DATA);
> +	iproc_adc_dbg_reg(dev, adc_priv, IPROC_SOFT_BYPASS_CONTROL);
> +	iproc_adc_dbg_reg(dev, adc_priv, IPROC_SOFT_BYPASS_DATA);
> +}
> +
> +static irqreturn_t iproc_adc_interrupt_handler(int irq, void *data)
> +{
> +	u32 channel_intr_status;
> +	u32 intr_status;
> +	u32 intr_mask;
> +	struct iio_dev *indio_dev = data;
> +	struct iproc_adc_priv *adc_priv = iio_priv(indio_dev);
> +
> +	/*
> +	 * This interrupt is shared with the touchscreen driver.
> +	 * Make sure this interrupt is intended for us.
> +	 * Handle only ADC channel specific interrupts.
> +	 */
> +	regmap_read(adc_priv->regmap, IPROC_INTERRUPT_STATUS, &intr_status);
> +	regmap_read(adc_priv->regmap, IPROC_INTERRUPT_MASK, &intr_mask);
> +	intr_status = intr_status & intr_mask;
> +	channel_intr_status = (intr_status & IPROC_ADC_INTR_MASK) >>
> +				IPROC_ADC_INTR;
> +	if (channel_intr_status)
> +		return IRQ_WAKE_THREAD;
> +
> +	return IRQ_NONE;
> +}
> +
> +static irqreturn_t iproc_adc_interrupt_thread(int irq, void *data)
> +{
> +	irqreturn_t retval = IRQ_NONE;
> +	struct iproc_adc_priv *adc_priv;
> +	struct iio_dev *indio_dev = data;
> +	unsigned int valid_entries;
> +	u32 intr_status;
> +	u32 intr_channels;
> +	u32 channel_status;
> +	u32 ch_intr_status;
> +
> +	adc_priv = iio_priv(indio_dev);
> +
> +	regmap_read(adc_priv->regmap, IPROC_INTERRUPT_STATUS, &intr_status);
> +	dev_dbg(&indio_dev->dev, "iproc_adc_interrupt_thread(),INTRPT_STS:%x\n",
> +			intr_status);
> +
> +	intr_channels = (intr_status & IPROC_ADC_INTR_MASK) >> IPROC_ADC_INTR;
> +	if (intr_channels) {
> +		regmap_read(adc_priv->regmap,
> +			    IPROC_ADC_CHANNEL_INTERRUPT_STATUS +
> +			    IPROC_ADC_CHANNEL_OFFSET * adc_priv->chan_id,
> +			    &ch_intr_status);
> +
> +		if (ch_intr_status & IPROC_ADC_CHANNEL_WTRMRK_INTR_MASK) {
> +			regmap_read(adc_priv->regmap,
> +					IPROC_ADC_CHANNEL_STATUS +
> +					IPROC_ADC_CHANNEL_OFFSET *
> +					adc_priv->chan_id,
> +					&channel_status);
> +
> +			valid_entries = ((channel_status &
> +				IPROC_ADC_CHANNEL_VALID_ENTERIES_MASK) >>
> +				IPROC_ADC_CHANNEL_VALID_ENTERIES);
> +			if (valid_entries >= 1) {
> +				regmap_read(adc_priv->regmap,
> +					IPROC_ADC_CHANNEL_DATA +
> +					IPROC_ADC_CHANNEL_OFFSET *
> +					adc_priv->chan_id,
> +					&adc_priv->chan_val);
> +				complete(&adc_priv->completion);
> +			} else {
> +				dev_err(&indio_dev->dev,
> +					"No data rcvd on channel %d\n",
> +					adc_priv->chan_id);
> +			}
> +			regmap_write(adc_priv->regmap,
> +					IPROC_ADC_CHANNEL_INTERRUPT_MASK +
> +					IPROC_ADC_CHANNEL_OFFSET *
> +					adc_priv->chan_id,
> +					(ch_intr_status &
> +					~(IPROC_ADC_CHANNEL_WTRMRK_INTR_MASK)));
> +		}
> +		regmap_write(adc_priv->regmap,
> +				IPROC_ADC_CHANNEL_INTERRUPT_STATUS +
> +				IPROC_ADC_CHANNEL_OFFSET * adc_priv->chan_id,
> +				ch_intr_status);
> +		regmap_write(adc_priv->regmap, IPROC_INTERRUPT_STATUS,
> +				intr_channels);
> +		retval = IRQ_HANDLED;
> +	}
> +
> +	return retval;
> +}
> +
> +static int iproc_adc_do_read(struct iio_dev *indio_dev,
> +			   int channel,
> +			   u16 *p_adc_data)
> +{
> +	int read_len = 0;
> +	u32 val;
> +	u32 mask;
> +	u32 val_check;
> +	int failed_cnt = 0;
> +	struct iproc_adc_priv *adc_priv = iio_priv(indio_dev);
> +
> +	mutex_lock(&adc_priv->mutex);
> +
> +	/*
> +	 * After a read is complete the ADC interrupts will be disabled so
> +	 * we can assume this section of code is safe from interrupts.
> +	 */
> +	adc_priv->chan_val = -1;
> +	adc_priv->chan_id = channel;
> +
> +	reinit_completion(&adc_priv->completion);
> +	/* Clear any pending interrupt */
> +	regmap_update_bits(adc_priv->regmap, IPROC_INTERRUPT_STATUS,
> +			IPROC_ADC_INTR_MASK | IPROC_ADC_AUXDATA_RDY_INTR,
> +			((0x0 << channel) << IPROC_ADC_INTR) |
> +			IPROC_ADC_AUXDATA_RDY_INTR);
> +
> +	/* Configure channel for snapshot mode and enable  */
> +	val = (BIT(IPROC_ADC_CHANNEL_ROUNDS) |
> +		(IPROC_ADC_CHANNEL_MODE_SNAPSHOT << IPROC_ADC_CHANNEL_MODE) |
> +		(0x1 << IPROC_ADC_CHANNEL_ENABLE));
> +
> +	mask = IPROC_ADC_CHANNEL_ROUNDS_MASK | IPROC_ADC_CHANNEL_MODE_MASK |
> +		IPROC_ADC_CHANNEL_ENABLE_MASK;
> +	regmap_update_bits(adc_priv->regmap, (IPROC_ADC_CHANNEL_REGCTL1 +
> +				IPROC_ADC_CHANNEL_OFFSET * channel),
> +				mask, val);
> +
> +	/* Set the Watermark for a channel */
> +	regmap_update_bits(adc_priv->regmap, (IPROC_ADC_CHANNEL_REGCTL2 +
> +					IPROC_ADC_CHANNEL_OFFSET * channel),
> +					IPROC_ADC_CHANNEL_WATERMARK_MASK,
> +					0x1);
> +
> +	/* Enable water mark interrupt */
> +	regmap_update_bits(adc_priv->regmap, (IPROC_ADC_CHANNEL_INTERRUPT_MASK +
> +					IPROC_ADC_CHANNEL_OFFSET *
> +					channel),
> +					IPROC_ADC_CHANNEL_WTRMRK_INTR_MASK,
> +					IPROC_ADC_WATER_MARK_INTR_ENABLE);
> +	regmap_read(adc_priv->regmap, IPROC_INTERRUPT_MASK, &val);
> +
> +	/* Enable ADC interrupt for a channel */
> +	val |= (BIT(channel) << IPROC_ADC_INTR);
> +	regmap_write(adc_priv->regmap, IPROC_INTERRUPT_MASK, val);
> +
> +	/*
> +	 * There seems to be a very rare issue where writing to this register
> +	 * does not take effect.  To work around the issue we will try multiple
> +	 * writes.  In total we will spend about 10*10 = 100 us attempting this.
> +	 * Testing has shown that this may loop a few time, but we have never
> +	 * hit the full count.
> +	 */
> +	regmap_read(adc_priv->regmap, IPROC_INTERRUPT_MASK, &val_check);
> +	while (val_check != val) {
> +		failed_cnt++;
> +
> +		if (failed_cnt > IPROC_ADC_INTMASK_RETRY_ATTEMPTS)
> +			break;
> +
> +		udelay(10);
> +		regmap_update_bits(adc_priv->regmap, IPROC_INTERRUPT_MASK,
> +				IPROC_ADC_INTR_MASK,
> +				((0x1 << channel) <<
> +				IPROC_ADC_INTR));
> +
> +		regmap_read(adc_priv->regmap, IPROC_INTERRUPT_MASK, &val_check);
> +	}
> +
> +	if (failed_cnt) {
> +		dev_dbg(&indio_dev->dev,
> +			"IntMask failed (%d times)", failed_cnt);
> +		if (failed_cnt > IPROC_ADC_INTMASK_RETRY_ATTEMPTS) {
> +			dev_err(&indio_dev->dev,
> +				"IntMask set failed. Read will likely fail.");
> +			read_len = -EIO;
> +			goto adc_err;
> +		};
> +	}
> +	regmap_read(adc_priv->regmap, IPROC_INTERRUPT_MASK, &val_check);
> +
> +	if (wait_for_completion_timeout(&adc_priv->completion,
> +		IPROC_ADC_READ_TIMEOUT) > 0) {
> +
> +		/* Only the lower 16 bits are relevant */
> +		*p_adc_data = adc_priv->chan_val & 0xFFFF;
> +		read_len = sizeof(*p_adc_data);
> +
> +	} else {
> +		/*
> +		 * We never got the interrupt, something went wrong.
> +		 * Perhaps the interrupt may still be coming, we do not want
> +		 * that now.  Lets disable the ADC interrupt, and clear the
> +		 * status to put it back in to normal state.
> +		 */
> +		read_len = -ETIMEDOUT;
> +		goto adc_err;
> +	}
> +	mutex_unlock(&adc_priv->mutex);
> +
> +	return read_len;
> +
> +adc_err:
> +	regmap_update_bits(adc_priv->regmap, IPROC_INTERRUPT_MASK,
> +			   IPROC_ADC_INTR_MASK,
> +			   ((0x0 << channel) << IPROC_ADC_INTR));
> +
> +	regmap_update_bits(adc_priv->regmap, IPROC_INTERRUPT_STATUS,
> +			   IPROC_ADC_INTR_MASK,
> +			   ((0x0 << channel) << IPROC_ADC_INTR));
> +
> +	dev_err(&indio_dev->dev, "Timed out waiting for ADC data!\n");
> +	iproc_adc_reg_dump(indio_dev);
> +	mutex_unlock(&adc_priv->mutex);
> +
> +	return read_len;
> +}
> +
> +static int iproc_adc_enable(struct iio_dev *indio_dev)
> +{
> +	u32 val;
> +	u32 channel_id;
> +	struct iproc_adc_priv *adc_priv = iio_priv(indio_dev);
> +	int ret;
> +
> +	/* Set i_amux = 3b'000, select channel 0 */
> +	ret = regmap_update_bits(adc_priv->regmap, IPROC_ANALOG_CONTROL,
> +				IPROC_ADC_CHANNEL_SEL_MASK, 0);
> +	if (ret) {
> +		dev_err(&indio_dev->dev,
> +			"failed to write IPROC_ANALOG_CONTROL %d\n", ret);
> +		return ret;
> +	}
> +	adc_priv->chan_val = -1;
> +
> +	/*
> +	 * PWR up LDO, ADC, and Band Gap (0 to enable)
> +	 * Also enable ADC controller (set high)
> +	 */
> +	ret = regmap_read(adc_priv->regmap, IPROC_REGCTL2, &val);
> +	if (ret) {
> +		dev_err(&indio_dev->dev,
> +			"failed to read IPROC_REGCTL2 %d\n", ret);
> +		return ret;
> +	}
> +
> +	val &= ~(IPROC_ADC_PWR_LDO | IPROC_ADC_PWR_ADC | IPROC_ADC_PWR_BG);
> +
> +	ret = regmap_write(adc_priv->regmap, IPROC_REGCTL2, val);
> +	if (ret) {
> +		dev_err(&indio_dev->dev,
> +			"failed to write IPROC_REGCTL2 %d\n", ret);
> +		return ret;
> +	}
> +
> +	ret = regmap_read(adc_priv->regmap, IPROC_REGCTL2, &val);
> +	if (ret) {
> +		dev_err(&indio_dev->dev,
> +			"failed to read IPROC_REGCTL2 %d\n", ret);
> +		return ret;
> +	}
> +
> +	val |= IPROC_ADC_CONTROLLER_EN;
> +	ret = regmap_write(adc_priv->regmap, IPROC_REGCTL2, val);
> +	if (ret) {
> +		dev_err(&indio_dev->dev,
> +			"failed to write IPROC_REGCTL2 %d\n", ret);
> +		return ret;
> +	}
> +
> +	for (channel_id = 0; channel_id < indio_dev->num_channels;
> +		channel_id++) {
> +		ret = regmap_write(adc_priv->regmap,
> +				IPROC_ADC_CHANNEL_INTERRUPT_MASK +
> +				IPROC_ADC_CHANNEL_OFFSET * channel_id, 0);
> +		if (ret) {
> +			dev_err(&indio_dev->dev,
> +			    "failed to write ADC_CHANNEL_INTERRUPT_MASK %d\n",
> +			    ret);
> +			return ret;
> +		}
> +
> +		ret = regmap_write(adc_priv->regmap,
> +				IPROC_ADC_CHANNEL_INTERRUPT_STATUS +
> +				IPROC_ADC_CHANNEL_OFFSET * channel_id, 0);
> +		if (ret) {
> +			dev_err(&indio_dev->dev,
> +			    "failed to write ADC_CHANNEL_INTERRUPT_STATUS %d\n",
> +			    ret);
> +			return ret;
> +		}
> +	}
> +
> +	return 0;
> +}
> +
> +static void iproc_adc_disable(struct iio_dev *indio_dev)
> +{
> +	u32 val;
> +	int ret;
> +	struct iproc_adc_priv *adc_priv = iio_priv(indio_dev);
> +
> +	ret = regmap_read(adc_priv->regmap, IPROC_REGCTL2, &val);
> +	if (ret) {
> +		dev_err(&indio_dev->dev,
> +			"failed to read IPROC_REGCTL2 %d\n", ret);
> +		return;
> +	}
> +
> +	val &= ~IPROC_ADC_CONTROLLER_EN;
> +	ret = regmap_write(adc_priv->regmap, IPROC_REGCTL2, val);
> +	if (ret) {
> +		dev_err(&indio_dev->dev,
> +			"failed to write IPROC_REGCTL2 %d\n", ret);
> +		return;
> +	}
> +}
> +
> +static int iproc_adc_read_raw(struct iio_dev *indio_dev,
> +			  struct iio_chan_spec const *chan,
> +			  int *val,
> +			  int *val2,
> +			  long mask)
> +{
> +	u16 adc_data;
> +	int err;
> +
> +	switch (mask) {
> +	case IIO_CHAN_INFO_RAW:
> +		err =  iproc_adc_do_read(indio_dev, chan->channel, &adc_data);
> +		if (err < 0)
> +			return err;
> +		*val = adc_data;
> +		return IIO_VAL_INT;
> +	case IIO_CHAN_INFO_SCALE:
> +		switch (chan->type) {
> +		case IIO_VOLTAGE:
> +			*val = 1800;
> +			*val2 = 10;
> +			return IIO_VAL_FRACTIONAL_LOG2;
> +		default:
> +			return -EINVAL;
> +		}
> +	default:
> +		return -EINVAL;
> +	}
> +}
> +
> +static const struct iio_info iproc_adc_iio_info = {
> +	.read_raw = &iproc_adc_read_raw,
> +	.driver_module = THIS_MODULE,
> +};
> +
> +#define IPROC_ADC_CHANNEL(_index, _id) {                \
> +	.type = IIO_VOLTAGE,                            \
> +	.indexed = 1,                                   \
> +	.channel = _index,                              \
> +	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),   \
> +	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
> +	.datasheet_name = _id,                          \
> +}
> +
> +static const struct iio_chan_spec iproc_adc_iio_channels[] = {
> +	IPROC_ADC_CHANNEL(0, "adc0"),
> +	IPROC_ADC_CHANNEL(1, "adc1"),
> +	IPROC_ADC_CHANNEL(2, "adc2"),
> +	IPROC_ADC_CHANNEL(3, "adc3"),
> +	IPROC_ADC_CHANNEL(4, "adc4"),
> +	IPROC_ADC_CHANNEL(5, "adc5"),
> +	IPROC_ADC_CHANNEL(6, "adc6"),
> +	IPROC_ADC_CHANNEL(7, "adc7"),
> +};
> +
> +static int iproc_adc_probe(struct platform_device *pdev)
> +{
> +	struct iproc_adc_priv *adc_priv;
> +	struct iio_dev *indio_dev = NULL;
> +	int ret;
> +
> +	indio_dev = devm_iio_device_alloc(&pdev->dev,
> +					sizeof(*adc_priv));
> +	if (!indio_dev) {
> +		dev_err(&pdev->dev, "failed to allocate iio device\n");
> +		return -ENOMEM;
> +	}
> +
> +	adc_priv = iio_priv(indio_dev);
> +	platform_set_drvdata(pdev, indio_dev);
> +
> +	mutex_init(&adc_priv->mutex);
> +
> +	init_completion(&adc_priv->completion);
> +
> +	adc_priv->regmap = syscon_regmap_lookup_by_phandle(pdev->dev.of_node,
> +			   "adc-syscon");
> +	if (IS_ERR(adc_priv->regmap)) {
> +		dev_err(&pdev->dev, "failed to get handle for tsc syscon\n");
> +		ret = PTR_ERR(adc_priv->regmap);
> +		return ret;
> +	}
> +
> +	adc_priv->adc_clk = devm_clk_get(&pdev->dev, "tsc_clk");
> +	if (IS_ERR(adc_priv->adc_clk)) {
> +		dev_err(&pdev->dev,
> +			"failed getting clock tsc_clk\n");
> +		ret = PTR_ERR(adc_priv->adc_clk);
> +		return ret;
> +	}
> +
> +	adc_priv->irqno = platform_get_irq(pdev, 0);
> +	if (adc_priv->irqno <= 0) {
> +		dev_err(&pdev->dev, "platform_get_irq failed\n");
> +		ret = -ENODEV;
> +		return ret;
> +	}
> +
> +	ret = regmap_update_bits(adc_priv->regmap, IPROC_REGCTL2,
> +				IPROC_ADC_AUXIN_SCAN_ENA, 0);
> +	if (ret) {
> +		dev_err(&pdev->dev, "failed to write IPROC_REGCTL2 %d\n", ret);
> +		return ret;
> +	}
> +
> +	ret = devm_request_threaded_irq(&pdev->dev, adc_priv->irqno,
> +				iproc_adc_interrupt_thread,
> +				iproc_adc_interrupt_handler,
> +				IRQF_SHARED, "iproc-adc", indio_dev);
> +	if (ret) {
> +		dev_err(&pdev->dev, "request_irq error %d\n", ret);
> +		return ret;
> +	}
> +
> +	ret = clk_prepare_enable(adc_priv->adc_clk);
> +	if (ret) {
> +		dev_err(&pdev->dev,
> +			"clk_prepare_enable failed %d\n", ret);
> +		return ret;
> +	}
> +
> +	ret = iproc_adc_enable(indio_dev);
> +	if (ret) {
> +		dev_err(&pdev->dev, "failed to enable adc %d\n", ret);
> +		goto err_adc_enable;
> +	}
> +
> +	indio_dev->name = "iproc-static-adc";
> +	indio_dev->dev.parent = &pdev->dev;
> +	indio_dev->dev.of_node = pdev->dev.of_node;
> +	indio_dev->info = &iproc_adc_iio_info;
> +	indio_dev->modes = INDIO_DIRECT_MODE;
> +	indio_dev->channels = iproc_adc_iio_channels;
> +	indio_dev->num_channels = ARRAY_SIZE(iproc_adc_iio_channels);
> +
> +	ret = iio_device_register(indio_dev);
> +	if (ret) {
> +		dev_err(&pdev->dev, "iio_device_register failed:err %d\n", ret);
> +		goto err_clk;
> +	}
> +
> +	return 0;
> +
> +err_clk:
> +	iproc_adc_disable(indio_dev);
> +err_adc_enable:
> +	clk_disable_unprepare(adc_priv->adc_clk);
> +
> +	return ret;
> +}
> +
> +static int iproc_adc_remove(struct platform_device *pdev)
> +{
> +	struct iio_dev *indio_dev = platform_get_drvdata(pdev);
> +	struct iproc_adc_priv *adc_priv = iio_priv(indio_dev);
> +
> +	iio_device_unregister(indio_dev);
> +	iproc_adc_disable(indio_dev);
> +	clk_disable_unprepare(adc_priv->adc_clk);
> +
> +	return 0;
> +}
> +
> +static const struct of_device_id iproc_adc_of_match[] = {
> +	{.compatible = "brcm,iproc-static-adc", },
> +	{ },
> +};
> +MODULE_DEVICE_TABLE(of, iproc_adc_of_match);
> +
> +static struct platform_driver iproc_adc_driver = {
> +	.probe  = iproc_adc_probe,
> +	.remove	= iproc_adc_remove,
> +	.driver	= {
> +		.name	= "iproc-static-adc",
> +		.of_match_table = of_match_ptr(iproc_adc_of_match),
> +	},
> +};
> +module_platform_driver(iproc_adc_driver);
> +
> +MODULE_DESCRIPTION("Broadcom iProc ADC controller driver");
> +MODULE_AUTHOR("Raveendra Padasalagi <raveendra.padasalagi@...adcom.com>");
> +MODULE_LICENSE("GPL v2");
> 

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