Message-Id: <1467099636-31855-3-git-send-email-raveendra.padasalagi@broadcom.com>
Date:	Tue, 28 Jun 2016 13:10:35 +0530
From:	Raveendra Padasalagi <raveendra.padasalagi@...adcom.com>
To:	Jonathan Cameron <jic23@...nel.org>,
	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,
	Raveendra Padasalagi <raveendra.padasalagi@...adcom.com>
Subject: [PATCH v4 2/3] iio: Add driver for Broadcom iproc-static-adc

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>
---
 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");
-- 
1.9.1

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