iio: adc: Add Renesas GyroADC driver

Add IIO driver for the Renesas RCar GyroADC block. This block is a simple 4/8-channel ADC which samples 12/15/24 bits of data every cycle from all channels.

Signed-off-by Marek Vasut <[email protected]>

Cc Geert Uytterhoeven <[email protected]>

Cc Simon Horman <horms+renesas-/[email protected]>

Cc Jonathan Cameron <[email protected]>

Cc [email protected]

---
V2: - Spelling fixes
- Rename the driver source file to rcar-gyroadc
- Rework the channel sample width handling
- Use iio_device_claim_mode_direct()
- Rename "renesas,rcar-gyroadc" to "renesas,r8a7791-gyroadc" and rename "renesas,rcar-gyroadc-r8a7792" to "renesas,r8a7792-gyroadc" to match the new naming scheme (WARNING: scif uses the old one!)
- Switch to using regulators for channel voltage reference, add new properties renesas,gyroadc-vref-chN-supply for N in 0..7
- Handle vref regulators as optional to, make channels without vref regulator return EINVAL on read.
- Fix module license to GPL
- Drop interrupt.h include
- Rename clk to iclk
- Rename RCar to R-Car
- Rework the invalid mode handling
- Don't print error message on EPROBE_DEFER
- Drop fclk handling, use runtime PM for that instead
V3: - More R-Car spelling fixes
- Flip checks for V2H, since that's the only one that has interrupt registers
- Replace if-else statement with switch statement in init_mode
- Use unsigned types where applicable
- Rework timing calculation slightly to drop if-else block
- Use DIV_ROUND_CLOSEST
V4: - Add renesas,rcar-gyroadc fallback compatible string into the bindings
- Rework the ADC bindings to use per-channel subdevs
- Support more compatible ADC chips
V5: - Reword the DT bindings, improve the description of the modes
- Improve the description in Kconfig
- Implement special DT bindings for the MB88101A 4-channel ADC and add special handling for this chip into the driver.
- Add missing ADC stop on failure, wrap it into a function
- Fail hard in case the DT properties are incorrect or missing
- Fix reporting of scale, so that channel * scale value is in mV
- Use fractional scale instead of int plus nano
- Use pm_runtime to disable the sampling 2 seconds after last used
V6: - Replace the indio_dev->name with "rcar-gyroadc" instead of OF node name

---
 .../bindings/iio/adc/renesas,gyroadc.txt           |  93 +++
 MAINTAINERS                                        |   6 +
 drivers/iio/adc/Kconfig                            |  13 +
 drivers/iio/adc/Makefile                           |   1 +
 drivers/iio/adc/rcar-gyroadc.c                     | 631 +++++++++++++++++++++
 5 files changed, 744 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/iio/adc/renesas,gyroadc.txt
 create mode 100644 drivers/iio/adc/rcar-gyroadc.c

Documentation/devicetree/bindings/iio/adc/renesas,gyroadc.txt new file +93 -0

new file mode 100644
index 000000000000..081947367135
@@ -0,0 +1,93 @@
+* Renesas RCar GyroADC device driver
+
+Required properties:
+- compatible:	Should be "renesas,<chip>-gyroadc", "renesas,rcar-gyroadc".
+		Use "renesas,r8a7792-gyroadc" for a GyroADC with interrupt
+		block found in R8A7792.
+- reg:		Address and length of the register set for the device
+- clocks:	References to all the clocks specified in the clock-names
+		property as specified in
+		Documentation/devicetree/bindings/clock/clock-bindings.txt.
+- clock-names:	Shall contain "fck" and "if". The "fck" is the GyroADC block
+		clock, the "if" is the interface clock.
+- power-domains: Must contain a reference to the PM domain, if available.
+- #address-cells: Should be <1> (setting for the subnodes) for all ADCs
+		except for "fujitsu,mb88101a". Should be <0> (setting for
+		only subnode) for "fujitsu,mb88101a".
+- #size-cells:	Should be <0> (setting for the subnodes)
+
+Sub-nodes:
+Optionally you can define subnodes which select the connected ADC type and
+reference voltage for the GyroADC channels.
+
+Required properties for subnodes:
+- compatible:	Should be either of:
+		"fujitsu,mb88101a"
+			- Fujitsu MB88101A compatible mode,
+			  12bit sampling, up to 4 channels can be sampled in
+			  round-robin fashion. One Fujitsu chip supplies four
+			  GyroADC channels with data as it contains four ADCs
+			  on the chip and thus for 4-channel operation, single
+			  MB88101A is required. The Cx chipselect lines of the
+			  MB88101A connect directly to two CHS lines of the
+			  GyroADC, no demuxer is required. The data out line
+			  of each MB88101A connects to a shared input pin of
+			  the GyroADC.
+		"ti,adcs7476" or "ti,adc121" or "adi,ad7476"
+			- TI ADCS7476 / TI ADC121 / ADI AD7476 compatible mode,
+			  15bit sampling, up to 8 channels can be sampled in
+			  round-robin fashion. One TI/ADI chip supplies single
+			  ADC channel with data, thus for 8-channel operation,
+			  8 chips are required. A 3:8 chipselect demuxer is
+			  required to connect the nCS line of the TI/ADI chips
+			  to the GyroADC, while MISO line of each TI/ADI ADC
+			  connects to a shared input pin of the GyroADC.
+		"maxim,max1162" or "maxim,max11100"
+			- Maxim MAX1162 / Maxim MAX11100 compatible mode,
+			  16bit sampling, up to 8 channels can be sampled in
+			  round-robin fashion. One Maxim chip supplies single
+			  ADC channel with data, thus for 8-channel operation,
+			  8 chips are required. A 3:8 chipselect demuxer is
+			  required to connect the nCS line of the MAX chips
+			  to the GyroADC, while MISO line of each Maxim ADC
+			  connects to a shared input pin of the GyroADC.
+- reg:		Should be the number of the analog input. Should be present
+		for all ADCs except "fujitsu,mb88101a".
+- vref-supply:	Reference to the channel reference voltage regulator.
+
+Example:
+	vref_max1162: regulator-vref-max1162 {
+		compatible = "regulator-fixed";
+
+		regulator-name = "MAX1162 Vref";
+		regulator-min-microvolt = <4096000>;
+		regulator-max-microvolt = <4096000>;
+	};
+
+	&adc {
+		compatible = "renesas,r8a7791-gyroadc", "renesas,rcar-gyroadc";
+		reg = <0 0xe6e54000 0 64>;
+		clocks = <&mstp9_clks R8A7791_CLK_GYROADC>, <&clk_65m>;
+		clock-names = "fck", "if";
+		power-domains = <&sysc R8A7791_PD_ALWAYS_ON>;
+
+		pinctrl-0 = <&adc_pins>;
+		pinctrl-names = "default";
+
+		status = "okay";
+
+		#address-cells = <1>;
+		#size-cells = <0>;
+
+		adc@0 {
+			reg = <0>;
+			compatible = "maxim,max1162";
+			vref-supply = <&vref_max1162>;
+		};
+
+		adc@1 {
+			reg = <1>;
+			compatible = "maxim,max1162";
+			vref-supply = <&vref_max1162>;
+		};
+	};

MAINTAINERS +6 -0

index 890fc9e3c191..498e8a755eb6 100644
@@ -10276,6 +10276,12 @@ L:	[email protected]
 F:	drivers/net/ethernet/renesas/
 F:	include/linux/sh_eth.h
 
+RENESAS R-CAR GYROADC DRIVER
+M:	Marek Vasut <[email protected]>
+L:	[email protected]
+S:	Supported
+F:	drivers/iio/adc/rcar_gyro_adc.c
+
 RENESAS USB2 PHY DRIVER
 M:	Yoshihiro Shimoda <[email protected]>
 L:	[email protected]

drivers/iio/adc/Kconfig +13 -0

index 99c051490eff..2fbc11f42740 100644
@@ -408,6 +408,19 @@ config QCOM_SPMI_VADC
 	  To compile this driver as a module, choose M here: the module will
 	  be called qcom-spmi-vadc.
 
+config RCAR_GYRO_ADC
+	tristate "Renesas R-Car GyroADC driver"
+	depends on ARCH_RCAR_GEN2 || (ARM && COMPILE_TEST)
+	help
+	  Say yes here to build support for the GyroADC found in Renesas
+	  R-Car Gen2 SoCs. This block is a simple SPI offload engine for
+	  reading data out of attached compatible ADCs in a round-robin
+	  fashion. Up to 4 or 8 ADC channels are supported by this block,
+	  depending on which ADCs are attached.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called rcar-gyroadc.
+
 config ROCKCHIP_SARADC
 	tristate "Rockchip SARADC driver"
 	depends on ARCH_ROCKCHIP || (ARM && COMPILE_TEST)

drivers/iio/adc/Makefile +1 -0

index 7a40c04c311f..13db7c2bffc8 100644
@@ -39,6 +39,7 @@ obj-$(CONFIG_NAU7802) += nau7802.o
 obj-$(CONFIG_PALMAS_GPADC) += palmas_gpadc.o
 obj-$(CONFIG_QCOM_SPMI_IADC) += qcom-spmi-iadc.o
 obj-$(CONFIG_QCOM_SPMI_VADC) += qcom-spmi-vadc.o
+obj-$(CONFIG_RCAR_GYRO_ADC) += rcar-gyroadc.o
 obj-$(CONFIG_ROCKCHIP_SARADC) += rockchip_saradc.o
 obj-$(CONFIG_STX104) += stx104.o
 obj-$(CONFIG_TI_ADC081C) += ti-adc081c.o

drivers/iio/adc/rcar-gyroadc.c new file +631 -0

new file mode 100644
index 000000000000..0c44f72c32a8
@@ -0,0 +1,631 @@
+/*
+ * Renesas R-Car GyroADC driver
+ *
+ * Copyright 2016 Marek Vasut <[email protected]>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * 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/module.h>
+#include <linux/platform_device.h>
+#include <linux/delay.h>
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/io.h>
+#include <linux/clk.h>
+#include <linux/of.h>
+#include <linux/of_irq.h>
+#include <linux/regulator/consumer.h>
+#include <linux/of_platform.h>
+#include <linux/err.h>
+#include <linux/pm_runtime.h>
+
+#include <linux/iio/iio.h>
+#include <linux/iio/sysfs.h>
+#include <linux/iio/trigger.h>
+
+#define DRIVER_NAME				"rcar-gyroadc"
+
+/* GyroADC registers. */
+#define RCAR_GYROADC_MODE_SELECT		0x00
+#define RCAR_GYROADC_MODE_SELECT_1_MB88101A	0x0
+#define RCAR_GYROADC_MODE_SELECT_2_ADCS7476	0x1
+#define RCAR_GYROADC_MODE_SELECT_3_MAX1162	0x3
+
+#define RCAR_GYROADC_START_STOP			0x04
+#define RCAR_GYROADC_START_STOP_START		BIT(0)
+
+#define RCAR_GYROADC_CLOCK_LENGTH		0x08
+#define RCAR_GYROADC_1_25MS_LENGTH		0x0c
+
+#define RCAR_GYROADC_REALTIME_DATA(ch)		(0x10 + ((ch) * 4))
+#define RCAR_GYROADC_100MS_ADDED_DATA(ch)	(0x30 + ((ch) * 4))
+#define RCAR_GYROADC_10MS_AVG_DATA(ch)		(0x50 + ((ch) * 4))
+
+#define RCAR_GYROADC_FIFO_STATUS		0x70
+#define RCAR_GYROADC_FIFO_STATUS_EMPTY(ch)	BIT(0 + (4 * (ch)))
+#define RCAR_GYROADC_FIFO_STATUS_FULL(ch)	BIT(1 + (4 * (ch)))
+#define RCAR_GYROADC_FIFO_STATUS_ERROR(ch)	BIT(2 + (4 * (ch)))
+
+#define RCAR_GYROADC_INTR			0x74
+#define RCAR_GYROADC_INTR_INT			BIT(0)
+
+#define RCAR_GYROADC_INTENR			0x78
+#define RCAR_GYROADC_INTENR_INTEN		BIT(0)
+
+#define RCAR_GYROADC_SAMPLE_RATE		800	/* Hz */
+
+#define RCAR_GYROADC_RUNTIME_PM_DELAY_MS	2000
+
+enum rcar_gyroadc_model {
+	RCAR_GYROADC_MODEL_DEFAULT,
+	RCAR_GYROADC_MODEL_R8A7792,
+};
+
+struct rcar_gyroadc {
+	struct device			*dev;
+	void __iomem			*regs;
+	struct clk			*iclk;
+	struct regulator		*vref[8];
+	unsigned int			num_channels;
+	enum rcar_gyroadc_model		model;
+	unsigned int			mode;
+	unsigned int			sample_width;
+};
+
+static void rcar_gyroadc_hw_init(struct rcar_gyroadc *priv)
+{
+	const unsigned long clk_mhz = clk_get_rate(priv->iclk) / 1000000;
+	const unsigned long clk_mul =
+		(priv->mode == RCAR_GYROADC_MODE_SELECT_1_MB88101A) ? 10 : 5;
+	unsigned long clk_len = clk_mhz * clk_mul;
+
+	/*
+	 * According to the R-Car Gen2 datasheet Rev. 1.01, Sept 08 2014,
+	 * page 77-7, clock length must be even number. If it's odd number,
+	 * add one.
+	 */
+	if (clk_len & 1)
+		clk_len++;
+
+	/* Stop the GyroADC. */
+	writel(0, priv->regs + RCAR_GYROADC_START_STOP);
+
+	/* Disable IRQ on V2H. */
+	if (priv->model == RCAR_GYROADC_MODEL_R8A7792)
+		writel(0, priv->regs + RCAR_GYROADC_INTENR);
+
+	/* Set mode and timing. */
+	writel(priv->mode, priv->regs + RCAR_GYROADC_MODE_SELECT);
+	writel(clk_len, priv->regs + RCAR_GYROADC_CLOCK_LENGTH);
+	writel(clk_mhz * 1250, priv->regs + RCAR_GYROADC_1_25MS_LENGTH);
+}
+
+static void rcar_gyroadc_hw_start(struct rcar_gyroadc *priv)
+{
+	/* Start sampling. */
+	writel(RCAR_GYROADC_START_STOP_START,
+	       priv->regs + RCAR_GYROADC_START_STOP);
+
+	/*
+	 * Wait for the first conversion to complete. This is longer than
+	 * the 1.25 mS in the datasheet because 1.25 mS is not enough for
+	 * the hardware to deliver the first sample and the hardware does
+	 * then return zeroes instead of valid data.
+	 */
+	mdelay(3);
+}
+
+static void rcar_gyroadc_hw_stop(struct rcar_gyroadc *priv)
+{
+	/* Stop the GyroADC. */
+	writel(0, priv->regs + RCAR_GYROADC_START_STOP);
+}
+
+#define RCAR_GYROADC_CHAN(_idx) {				\
+	.type			= IIO_VOLTAGE,			\
+	.indexed		= 1,				\
+	.channel		= (_idx),			\
+	.info_mask_separate	= BIT(IIO_CHAN_INFO_RAW) |	\
+				  BIT(IIO_CHAN_INFO_SCALE),	\
+	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SAMP_FREQ), \
+}
+
+static const struct iio_chan_spec rcar_gyroadc_iio_channels_1[] = {
+	RCAR_GYROADC_CHAN(0),
+	RCAR_GYROADC_CHAN(1),
+	RCAR_GYROADC_CHAN(2),
+	RCAR_GYROADC_CHAN(3),
+};
+
+static const struct iio_chan_spec rcar_gyroadc_iio_channels_2[] = {
+	RCAR_GYROADC_CHAN(0),
+	RCAR_GYROADC_CHAN(1),
+	RCAR_GYROADC_CHAN(2),
+	RCAR_GYROADC_CHAN(3),
+	RCAR_GYROADC_CHAN(4),
+	RCAR_GYROADC_CHAN(5),
+	RCAR_GYROADC_CHAN(6),
+	RCAR_GYROADC_CHAN(7),
+};
+
+static const struct iio_chan_spec rcar_gyroadc_iio_channels_3[] = {
+	RCAR_GYROADC_CHAN(0),
+	RCAR_GYROADC_CHAN(1),
+	RCAR_GYROADC_CHAN(2),
+	RCAR_GYROADC_CHAN(3),
+	RCAR_GYROADC_CHAN(4),
+	RCAR_GYROADC_CHAN(5),
+	RCAR_GYROADC_CHAN(6),
+	RCAR_GYROADC_CHAN(7),
+};
+
+static int rcar_gyroadc_set_power(struct rcar_gyroadc *priv, bool on)
+{
+	struct device *dev = priv->dev;
+	int ret;
+
+	if (on) {
+		ret = pm_runtime_get_sync(dev);
+		if (ret < 0)
+			pm_runtime_put_noidle(dev);
+	} else {
+		pm_runtime_mark_last_busy(dev);
+		ret = pm_runtime_put_autosuspend(dev);
+	}
+
+	return ret;
+}
+
+static int rcar_gyroadc_read_raw(struct iio_dev *indio_dev,
+				 struct iio_chan_spec const *chan,
+				 int *val, int *val2, long mask)
+{
+	struct rcar_gyroadc *priv = iio_priv(indio_dev);
+	struct regulator *consumer;
+	unsigned int datareg = RCAR_GYROADC_REALTIME_DATA(chan->channel);
+	unsigned int vref;
+	int ret;
+
+	/*
+	 * MB88101 is special in that it has only single regulator for
+	 * all four channels.
+	 */
+	if (priv->mode == RCAR_GYROADC_MODE_SELECT_1_MB88101A)
+		consumer = priv->vref[0];
+	else
+		consumer = priv->vref[chan->channel];
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		if (chan->type != IIO_VOLTAGE)
+			return -EINVAL;
+
+		/* Channel not connected. */
+		if (!consumer)
+			return -EINVAL;
+
+		ret = iio_device_claim_direct_mode(indio_dev);
+		if (ret)
+			return ret;
+
+		ret = rcar_gyroadc_set_power(priv, true);
+		if (ret < 0) {
+			iio_device_release_direct_mode(indio_dev);
+			return ret;
+		}
+
+		*val = readl(priv->regs + datareg);
+		*val &= BIT(priv->sample_width) - 1;
+
+		ret = rcar_gyroadc_set_power(priv, false);
+		iio_device_release_direct_mode(indio_dev);
+		if (ret < 0)
+			return ret;
+
+		return IIO_VAL_INT;
+	case IIO_CHAN_INFO_SCALE:
+		/* Channel not connected. */
+		if (!consumer)
+			return -EINVAL;
+
+		vref = regulator_get_voltage(consumer);
+		*val = vref / 1000;
+		*val2 = 1 << priv->sample_width;
+
+		return IIO_VAL_FRACTIONAL;
+	case IIO_CHAN_INFO_SAMP_FREQ:
+		*val = RCAR_GYROADC_SAMPLE_RATE;
+
+		return IIO_VAL_INT;
+	default:
+		return -EINVAL;
+	}
+}
+
+static int rcar_gyroadc_reg_access(struct iio_dev *indio_dev,
+				   unsigned int reg, unsigned int writeval,
+				   unsigned int *readval)
+{
+	struct rcar_gyroadc *priv = iio_priv(indio_dev);
+	unsigned int maxreg = RCAR_GYROADC_FIFO_STATUS;
+
+	if (readval == NULL)
+		return -EINVAL;
+
+	if (reg % 4)
+		return -EINVAL;
+
+	/* Handle the V2H case with extra interrupt block. */
+	if (priv->model == RCAR_GYROADC_MODEL_R8A7792)
+		maxreg = RCAR_GYROADC_INTENR;
+
+	if (reg > maxreg)
+		return -EINVAL;
+
+	*readval = readl(priv->regs + reg);
+
+	return 0;
+}
+
+static const struct iio_info rcar_gyroadc_iio_info = {
+	.driver_module		= THIS_MODULE,
+	.read_raw		= rcar_gyroadc_read_raw,
+	.debugfs_reg_access	= rcar_gyroadc_reg_access,
+};
+
+static const struct of_device_id rcar_gyroadc_match[] = {
+	{
+		/* R-Car compatible GyroADC */
+		.compatible	= "renesas,rcar-gyroadc",
+		.data		= (void *)RCAR_GYROADC_MODEL_DEFAULT,
+	}, {
+		/* R-Car V2H specialty with interrupt registers. */
+		.compatible	= "renesas,r8a7792-gyroadc",
+		.data		= (void *)RCAR_GYROADC_MODEL_R8A7792,
+	}, {
+		/* sentinel */
+	}
+};
+
+MODULE_DEVICE_TABLE(of, rcar_gyroadc_match);
+
+static const struct of_device_id rcar_gyroadc_child_match[] = {
+	/* Mode 1 ADCs */
+	{
+		.compatible	= "fujitsu,mb88101a",
+		.data		= (void *)RCAR_GYROADC_MODE_SELECT_1_MB88101A,
+	},
+	/* Mode 2 ADCs */
+	{
+		.compatible	= "ti,adcs7476",
+		.data		= (void *)RCAR_GYROADC_MODE_SELECT_2_ADCS7476,
+	}, {
+		.compatible	= "ti,adc121",
+		.data		= (void *)RCAR_GYROADC_MODE_SELECT_2_ADCS7476,
+	}, {
+		.compatible	= "adi,ad7476",
+		.data		= (void *)RCAR_GYROADC_MODE_SELECT_2_ADCS7476,
+	},
+	/* Mode 3 ADCs */
+	{
+		.compatible	= "maxim,max1162",
+		.data		= (void *)RCAR_GYROADC_MODE_SELECT_3_MAX1162,
+	}, {
+		.compatible	= "maxim,max11100",
+		.data		= (void *)RCAR_GYROADC_MODE_SELECT_3_MAX1162,
+	},
+	{ /* sentinel */ }
+};
+
+static int rcar_gyroadc_parse_subdevs(struct iio_dev *indio_dev)
+{
+	const struct of_device_id *of_id;
+	const struct iio_chan_spec *channels;
+	struct rcar_gyroadc *priv = iio_priv(indio_dev);
+	struct device *dev = priv->dev;
+	struct device_node *np = dev->of_node;
+	struct device_node *child;
+	struct regulator *vref;
+	unsigned int reg;
+	unsigned int adcmode, childmode;
+	unsigned int sample_width;
+	unsigned int num_channels;
+	int ret, first = 1;
+
+	for_each_child_of_node(np, child) {
+		of_id = of_match_node(rcar_gyroadc_child_match, child);
+		if (!of_id) {
+			dev_err(dev, "Ignoring unsupported ADC \"%s\".",
+				child->name);
+			continue;
+		}
+
+		childmode = (unsigned int)of_id->data;
+		switch (childmode) {
+		case RCAR_GYROADC_MODE_SELECT_1_MB88101A:
+			sample_width = 12;
+			channels = rcar_gyroadc_iio_channels_1;
+			num_channels = ARRAY_SIZE(rcar_gyroadc_iio_channels_1);
+			break;
+		case RCAR_GYROADC_MODE_SELECT_2_ADCS7476:
+			sample_width = 15;
+			channels = rcar_gyroadc_iio_channels_2;
+			num_channels = ARRAY_SIZE(rcar_gyroadc_iio_channels_2);
+			break;
+		case RCAR_GYROADC_MODE_SELECT_3_MAX1162:
+			sample_width = 16;
+			channels = rcar_gyroadc_iio_channels_3;
+			num_channels = ARRAY_SIZE(rcar_gyroadc_iio_channels_3);
+			break;
+		}
+
+		/*
+		 * MB88101 is special in that it's only a single chip taking
+		 * up all the CHS lines. Thus, the DT binding is also special
+		 * and has no reg property. If we run into such ADC, handle
+		 * it here.
+		 */
+		if (childmode == RCAR_GYROADC_MODE_SELECT_1_MB88101A) {
+			reg = 0;
+		} else {
+			ret = of_property_read_u32(child, "reg", &reg);
+			if (ret) {
+				dev_err(dev,
+					"Failed to get child reg property of ADC \"%s\".\n",
+					child->name);
+				return ret;
+			}
+
+			/* Channel number is too high. */
+			if (reg >= num_channels) {
+				dev_err(dev,
+					"Only %i channels supported with %s, but reg = <%i>.\n",
+					num_channels, child->name, reg);
+				return ret;
+			}
+		}
+
+		/* Child node selected different mode than the rest. */
+		if (!first && (adcmode != childmode)) {
+			dev_err(dev,
+				"Channel %i uses different ADC mode than the rest.\n",
+				reg);
+			return ret;
+		}
+
+		/* Channel is valid, grab the regulator. */
+		dev->of_node = child;
+		vref = devm_regulator_get(dev, "vref");
+		dev->of_node = np;
+		if (IS_ERR(vref)) {
+			dev_dbg(dev, "Channel %i 'vref' supply not connected.\n",
+				reg);
+			return PTR_ERR(vref);
+		}
+
+		priv->vref[reg] = vref;
+
+		if (!first)
+			continue;
+
+		/* First child node which passed sanity tests. */
+		adcmode = childmode;
+		first = 0;
+
+		priv->num_channels = num_channels;
+		priv->mode = childmode;
+		priv->sample_width = sample_width;
+
+		indio_dev->channels = channels;
+		indio_dev->num_channels = num_channels;
+
+		/*
+		 * MB88101 is special and we only have one such device
+		 * attached to the GyroADC at a time, so if we found it,
+		 * we can stop parsing here.
+		 */
+		if (childmode == RCAR_GYROADC_MODE_SELECT_1_MB88101A)
+			break;
+	}
+
+	if (first) {
+		dev_err(dev, "No valid ADC channels found, aborting.\n");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static void rcar_gyroadc_deinit_supplies(struct iio_dev *indio_dev)
+{
+	struct rcar_gyroadc *priv = iio_priv(indio_dev);
+	unsigned int i;
+
+	for (i = 0; i < priv->num_channels; i++) {
+		if (!priv->vref[i])
+			continue;
+
+		regulator_disable(priv->vref[i]);
+	}
+}
+
+static int rcar_gyroadc_init_supplies(struct iio_dev *indio_dev)
+{
+	struct rcar_gyroadc *priv = iio_priv(indio_dev);
+	struct device *dev = priv->dev;
+	unsigned int i;
+	int ret;
+
+	for (i = 0; i < priv->num_channels; i++) {
+		if (!priv->vref[i])
+			continue;
+
+		ret = regulator_enable(priv->vref[i]);
+		if (ret) {
+			dev_err(dev, "Failed to enable regulator %i (ret=%i)\n",
+				i, ret);
+			goto err;
+		}
+	}
+
+	return 0;
+
+err:
+	rcar_gyroadc_deinit_supplies(indio_dev);
+	return ret;
+}
+
+static int rcar_gyroadc_probe(struct platform_device *pdev)
+{
+	const struct of_device_id *of_id =
+		of_match_device(rcar_gyroadc_match, &pdev->dev);
+	struct device *dev = &pdev->dev;
+	struct rcar_gyroadc *priv;
+	struct iio_dev *indio_dev;
+	struct resource *mem;
+	int ret;
+
+	indio_dev = devm_iio_device_alloc(dev, sizeof(*priv));
+	if (!indio_dev) {
+		dev_err(dev, "Failed to allocate IIO device.\n");
+		return -ENOMEM;
+	}
+
+	priv = iio_priv(indio_dev);
+	priv->dev = dev;
+
+	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	priv->regs = devm_ioremap_resource(dev, mem);
+	if (IS_ERR(priv->regs))
+		return PTR_ERR(priv->regs);
+
+	priv->iclk = devm_clk_get(dev, "if");
+	if (IS_ERR(priv->iclk)) {
+		ret = PTR_ERR(priv->iclk);
+		if (ret != -EPROBE_DEFER)
+			dev_err(dev, "Failed to get IF clock (ret=%i)\n", ret);
+		return ret;
+	}
+
+	ret = rcar_gyroadc_parse_subdevs(indio_dev);
+	if (ret)
+		return ret;
+
+	ret = rcar_gyroadc_init_supplies(indio_dev);
+	if (ret)
+		return ret;
+
+	priv->model = (enum rcar_gyroadc_model)of_id->data;
+
+	platform_set_drvdata(pdev, indio_dev);
+
+	indio_dev->name = DRIVER_NAME;
+	indio_dev->dev.parent = dev;
+	indio_dev->dev.of_node = pdev->dev.of_node;
+	indio_dev->info = &rcar_gyroadc_iio_info;
+	indio_dev->modes = INDIO_DIRECT_MODE;
+
+	ret = clk_prepare_enable(priv->iclk);
+	if (ret) {
+		dev_err(dev, "Could not prepare or enable the IF clock.\n");
+		goto err_clk_if_enable;
+	}
+
+	pm_runtime_set_autosuspend_delay(dev, RCAR_GYROADC_RUNTIME_PM_DELAY_MS);
+	pm_runtime_use_autosuspend(dev);
+	pm_runtime_enable(dev);
+
+	pm_runtime_get_sync(dev);
+	rcar_gyroadc_hw_init(priv);
+	rcar_gyroadc_hw_start(priv);
+
+	ret = iio_device_register(indio_dev);
+	if (ret) {
+		dev_err(dev, "Couldn't register IIO device.\n");
+		goto err_iio_device_register;
+	}
+
+	pm_runtime_put_sync(dev);
+
+	return 0;
+
+err_iio_device_register:
+	rcar_gyroadc_hw_stop(priv);
+	pm_runtime_put_sync(dev);
+	pm_runtime_disable(dev);
+	pm_runtime_set_suspended(dev);
+	clk_disable_unprepare(priv->iclk);
+err_clk_if_enable:
+	rcar_gyroadc_deinit_supplies(indio_dev);
+
+	return ret;
+}
+
+static int rcar_gyroadc_remove(struct platform_device *pdev)
+{
+	struct iio_dev *indio_dev = platform_get_drvdata(pdev);
+	struct rcar_gyroadc *priv = iio_priv(indio_dev);
+	struct device *dev = priv->dev;
+
+	iio_device_unregister(indio_dev);
+	pm_runtime_get_sync(dev);
+	rcar_gyroadc_hw_stop(priv);
+	pm_runtime_put_sync(dev);
+	pm_runtime_disable(dev);
+	pm_runtime_set_suspended(dev);
+	clk_disable_unprepare(priv->iclk);
+	rcar_gyroadc_deinit_supplies(indio_dev);
+
+	return 0;
+}
+
+#if defined(CONFIG_PM)
+static int rcar_gyroadc_suspend(struct device *dev)
+{
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	struct rcar_gyroadc *priv = iio_priv(indio_dev);
+
+	rcar_gyroadc_hw_stop(priv);
+
+	return 0;
+}
+
+static int rcar_gyroadc_resume(struct device *dev)
+{
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	struct rcar_gyroadc *priv = iio_priv(indio_dev);
+
+	rcar_gyroadc_hw_start(priv);
+
+	return 0;
+}
+#endif
+
+static const struct dev_pm_ops rcar_gyroadc_pm_ops = {
+	SET_RUNTIME_PM_OPS(rcar_gyroadc_suspend, rcar_gyroadc_resume, NULL)
+};
+
+static struct platform_driver rcar_gyroadc_driver = {
+	.probe          = rcar_gyroadc_probe,
+	.remove         = rcar_gyroadc_remove,
+	.driver         = {
+		.name		= DRIVER_NAME,
+		.of_match_table	= rcar_gyroadc_match,
+		.pm		= &rcar_gyroadc_pm_ops,
+	},
+};
+
+module_platform_driver(rcar_gyroadc_driver);
+
+MODULE_AUTHOR("Marek Vasut <[email protected]>");
+MODULE_DESCRIPTION("Renesas R-Car GyroADC driver");
+MODULE_LICENSE("GPL");

Quoted 9 lines · Marek Vasut

Add IIO driver for the Renesas RCar GyroADC block. This block is a simple 4/8-channel ADC which samples 12/15/24 bits of data every cycle from all channels.

Signed-off-by Marek Vasut <[email protected]>

Cc Geert Uytterhoeven <[email protected]>

Cc Simon Horman <[email protected]>

Cc Jonathan Cameron <[email protected]>

Cc [email protected]

Hi Marek,

One thing I hadn't picked up on earlier. This hasn't been going to the devicetree list or maintainers. I'd like an ack from them on the bindings as they are a little 'unusual' given the odd nature of the part.

Cc'd Rob, Mark and the list.

Jonathan

Quoted 839 lines

---
V2: - Spelling fixes
- Rename the driver source file to rcar-gyroadc
- Rework the channel sample width handling
- Use iio_device_claim_mode_direct()
- Rename "renesas,rcar-gyroadc" to "renesas,r8a7791-gyroadc" and rename "renesas,rcar-gyroadc-r8a7792" to "renesas,r8a7792-gyroadc" to match the new naming scheme (WARNING: scif uses the old one!)
- Switch to using regulators for channel voltage reference, add new properties renesas,gyroadc-vref-chN-supply for N in 0..7
- Handle vref regulators as optional to, make channels without vref regulator return EINVAL on read.
- Fix module license to GPL
- Drop interrupt.h include
- Rename clk to iclk
- Rename RCar to R-Car
- Rework the invalid mode handling
- Don't print error message on EPROBE_DEFER
- Drop fclk handling, use runtime PM for that instead
V3: - More R-Car spelling fixes
- Flip checks for V2H, since that's the only one that has interrupt registers
- Replace if-else statement with switch statement in init_mode
- Use unsigned types where applicable
- Rework timing calculation slightly to drop if-else block
- Use DIV_ROUND_CLOSEST
V4: - Add renesas,rcar-gyroadc fallback compatible string into the bindings
- Rework the ADC bindings to use per-channel subdevs
- Support more compatible ADC chips
V5: - Reword the DT bindings, improve the description of the modes
- Improve the description in Kconfig
- Implement special DT bindings for the MB88101A 4-channel ADC and add special handling for this chip into the driver.
- Add missing ADC stop on failure, wrap it into a function
- Fail hard in case the DT properties are incorrect or missing
- Fix reporting of scale, so that channel * scale value is in mV
- Use fractional scale instead of int plus nano
- Use pm_runtime to disable the sampling 2 seconds after last used
V6: - Replace the indio_dev->name with "rcar-gyroadc" instead of OF node name

---
 .../bindings/iio/adc/renesas,gyroadc.txt           |  93 +++
 MAINTAINERS                                        |   6 +
 drivers/iio/adc/Kconfig                            |  13 +
 drivers/iio/adc/Makefile                           |   1 +
 drivers/iio/adc/rcar-gyroadc.c                     | 631 +++++++++++++++++++++
 5 files changed, 744 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/iio/adc/renesas,gyroadc.txt
 create mode 100644 drivers/iio/adc/rcar-gyroadc.c

Documentation/devicetree/bindings/iio/adc/renesas,gyroadc.txt new file +93 -0

new file mode 100644
index 000000000000..081947367135
@@ -0,0 +1,93 @@
+* Renesas RCar GyroADC device driver
+
+Required properties:
+- compatible:	Should be "renesas,<chip>-gyroadc", "renesas,rcar-gyroadc".
+		Use "renesas,r8a7792-gyroadc" for a GyroADC with interrupt
+		block found in R8A7792.
+- reg:		Address and length of the register set for the device
+- clocks:	References to all the clocks specified in the clock-names
+		property as specified in
+		Documentation/devicetree/bindings/clock/clock-bindings.txt.
+- clock-names:	Shall contain "fck" and "if". The "fck" is the GyroADC block
+		clock, the "if" is the interface clock.
+- power-domains: Must contain a reference to the PM domain, if available.
+- #address-cells: Should be <1> (setting for the subnodes) for all ADCs
+		except for "fujitsu,mb88101a". Should be <0> (setting for
+		only subnode) for "fujitsu,mb88101a".
+- #size-cells:	Should be <0> (setting for the subnodes)
+
+Sub-nodes:
+Optionally you can define subnodes which select the connected ADC type and
+reference voltage for the GyroADC channels.
+
+Required properties for subnodes:
+- compatible:	Should be either of:
+		"fujitsu,mb88101a"
+			- Fujitsu MB88101A compatible mode,
+			  12bit sampling, up to 4 channels can be sampled in
+			  round-robin fashion. One Fujitsu chip supplies four
+			  GyroADC channels with data as it contains four ADCs
+			  on the chip and thus for 4-channel operation, single
+			  MB88101A is required. The Cx chipselect lines of the
+			  MB88101A connect directly to two CHS lines of the
+			  GyroADC, no demuxer is required. The data out line
+			  of each MB88101A connects to a shared input pin of
+			  the GyroADC.
+		"ti,adcs7476" or "ti,adc121" or "adi,ad7476"
+			- TI ADCS7476 / TI ADC121 / ADI AD7476 compatible mode,
+			  15bit sampling, up to 8 channels can be sampled in
+			  round-robin fashion. One TI/ADI chip supplies single
+			  ADC channel with data, thus for 8-channel operation,
+			  8 chips are required. A 3:8 chipselect demuxer is
+			  required to connect the nCS line of the TI/ADI chips
+			  to the GyroADC, while MISO line of each TI/ADI ADC
+			  connects to a shared input pin of the GyroADC.
+		"maxim,max1162" or "maxim,max11100"
+			- Maxim MAX1162 / Maxim MAX11100 compatible mode,
+			  16bit sampling, up to 8 channels can be sampled in
+			  round-robin fashion. One Maxim chip supplies single
+			  ADC channel with data, thus for 8-channel operation,
+			  8 chips are required. A 3:8 chipselect demuxer is
+			  required to connect the nCS line of the MAX chips
+			  to the GyroADC, while MISO line of each Maxim ADC
+			  connects to a shared input pin of the GyroADC.
+- reg:		Should be the number of the analog input. Should be present
+		for all ADCs except "fujitsu,mb88101a".
+- vref-supply:	Reference to the channel reference voltage regulator.
+
+Example:
+	vref_max1162: regulator-vref-max1162 {
+		compatible = "regulator-fixed";
+
+		regulator-name = "MAX1162 Vref";
+		regulator-min-microvolt = <4096000>;
+		regulator-max-microvolt = <4096000>;
+	};
+
+	&adc {
+		compatible = "renesas,r8a7791-gyroadc", "renesas,rcar-gyroadc";
+		reg = <0 0xe6e54000 0 64>;
+		clocks = <&mstp9_clks R8A7791_CLK_GYROADC>, <&clk_65m>;
+		clock-names = "fck", "if";
+		power-domains = <&sysc R8A7791_PD_ALWAYS_ON>;
+
+		pinctrl-0 = <&adc_pins>;
+		pinctrl-names = "default";
+
+		status = "okay";
+
+		#address-cells = <1>;
+		#size-cells = <0>;
+
+		adc@0 {
+			reg = <0>;
+			compatible = "maxim,max1162";
+			vref-supply = <&vref_max1162>;
+		};
+
+		adc@1 {
+			reg = <1>;
+			compatible = "maxim,max1162";
+			vref-supply = <&vref_max1162>;
+		};
+	};

MAINTAINERS +6 -0

index 890fc9e3c191..498e8a755eb6 100644
@@ -10276,6 +10276,12 @@ L:	[email protected]
 F:	drivers/net/ethernet/renesas/
 F:	include/linux/sh_eth.h
 
+RENESAS R-CAR GYROADC DRIVER
+M:	Marek Vasut <[email protected]>
+L:	[email protected]
+S:	Supported
+F:	drivers/iio/adc/rcar_gyro_adc.c
+
 RENESAS USB2 PHY DRIVER
 M:	Yoshihiro Shimoda <[email protected]>
 L:	[email protected]

drivers/iio/adc/Kconfig +13 -0

index 99c051490eff..2fbc11f42740 100644
@@ -408,6 +408,19 @@ config QCOM_SPMI_VADC
 	  To compile this driver as a module, choose M here: the module will
 	  be called qcom-spmi-vadc.
 
+config RCAR_GYRO_ADC
+	tristate "Renesas R-Car GyroADC driver"
+	depends on ARCH_RCAR_GEN2 || (ARM && COMPILE_TEST)
+	help
+	  Say yes here to build support for the GyroADC found in Renesas
+	  R-Car Gen2 SoCs. This block is a simple SPI offload engine for
+	  reading data out of attached compatible ADCs in a round-robin
+	  fashion. Up to 4 or 8 ADC channels are supported by this block,
+	  depending on which ADCs are attached.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called rcar-gyroadc.
+
 config ROCKCHIP_SARADC
 	tristate "Rockchip SARADC driver"
 	depends on ARCH_ROCKCHIP || (ARM && COMPILE_TEST)

drivers/iio/adc/Makefile +1 -0

index 7a40c04c311f..13db7c2bffc8 100644
@@ -39,6 +39,7 @@ obj-$(CONFIG_NAU7802) += nau7802.o
 obj-$(CONFIG_PALMAS_GPADC) += palmas_gpadc.o
 obj-$(CONFIG_QCOM_SPMI_IADC) += qcom-spmi-iadc.o
 obj-$(CONFIG_QCOM_SPMI_VADC) += qcom-spmi-vadc.o
+obj-$(CONFIG_RCAR_GYRO_ADC) += rcar-gyroadc.o
 obj-$(CONFIG_ROCKCHIP_SARADC) += rockchip_saradc.o
 obj-$(CONFIG_STX104) += stx104.o
 obj-$(CONFIG_TI_ADC081C) += ti-adc081c.o

drivers/iio/adc/rcar-gyroadc.c new file +631 -0

new file mode 100644
index 000000000000..0c44f72c32a8
@@ -0,0 +1,631 @@
+/*
+ * Renesas R-Car GyroADC driver
+ *
+ * Copyright 2016 Marek Vasut <[email protected]>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * 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/module.h>
+#include <linux/platform_device.h>
+#include <linux/delay.h>
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/io.h>
+#include <linux/clk.h>
+#include <linux/of.h>
+#include <linux/of_irq.h>
+#include <linux/regulator/consumer.h>
+#include <linux/of_platform.h>
+#include <linux/err.h>
+#include <linux/pm_runtime.h>
+
+#include <linux/iio/iio.h>
+#include <linux/iio/sysfs.h>
+#include <linux/iio/trigger.h>
+
+#define DRIVER_NAME				"rcar-gyroadc"
+
+/* GyroADC registers. */
+#define RCAR_GYROADC_MODE_SELECT		0x00
+#define RCAR_GYROADC_MODE_SELECT_1_MB88101A	0x0
+#define RCAR_GYROADC_MODE_SELECT_2_ADCS7476	0x1
+#define RCAR_GYROADC_MODE_SELECT_3_MAX1162	0x3
+
+#define RCAR_GYROADC_START_STOP			0x04
+#define RCAR_GYROADC_START_STOP_START		BIT(0)
+
+#define RCAR_GYROADC_CLOCK_LENGTH		0x08
+#define RCAR_GYROADC_1_25MS_LENGTH		0x0c
+
+#define RCAR_GYROADC_REALTIME_DATA(ch)		(0x10 + ((ch) * 4))
+#define RCAR_GYROADC_100MS_ADDED_DATA(ch)	(0x30 + ((ch) * 4))
+#define RCAR_GYROADC_10MS_AVG_DATA(ch)		(0x50 + ((ch) * 4))
+
+#define RCAR_GYROADC_FIFO_STATUS		0x70
+#define RCAR_GYROADC_FIFO_STATUS_EMPTY(ch)	BIT(0 + (4 * (ch)))
+#define RCAR_GYROADC_FIFO_STATUS_FULL(ch)	BIT(1 + (4 * (ch)))
+#define RCAR_GYROADC_FIFO_STATUS_ERROR(ch)	BIT(2 + (4 * (ch)))
+
+#define RCAR_GYROADC_INTR			0x74
+#define RCAR_GYROADC_INTR_INT			BIT(0)
+
+#define RCAR_GYROADC_INTENR			0x78
+#define RCAR_GYROADC_INTENR_INTEN		BIT(0)
+
+#define RCAR_GYROADC_SAMPLE_RATE		800	/* Hz */
+
+#define RCAR_GYROADC_RUNTIME_PM_DELAY_MS	2000
+
+enum rcar_gyroadc_model {
+	RCAR_GYROADC_MODEL_DEFAULT,
+	RCAR_GYROADC_MODEL_R8A7792,
+};
+
+struct rcar_gyroadc {
+	struct device			*dev;
+	void __iomem			*regs;
+	struct clk			*iclk;
+	struct regulator		*vref[8];
+	unsigned int			num_channels;
+	enum rcar_gyroadc_model		model;
+	unsigned int			mode;
+	unsigned int			sample_width;
+};
+
+static void rcar_gyroadc_hw_init(struct rcar_gyroadc *priv)
+{
+	const unsigned long clk_mhz = clk_get_rate(priv->iclk) / 1000000;
+	const unsigned long clk_mul =
+		(priv->mode == RCAR_GYROADC_MODE_SELECT_1_MB88101A) ? 10 : 5;
+	unsigned long clk_len = clk_mhz * clk_mul;
+
+	/*
+	 * According to the R-Car Gen2 datasheet Rev. 1.01, Sept 08 2014,
+	 * page 77-7, clock length must be even number. If it's odd number,
+	 * add one.
+	 */
+	if (clk_len & 1)
+		clk_len++;
+
+	/* Stop the GyroADC. */
+	writel(0, priv->regs + RCAR_GYROADC_START_STOP);
+
+	/* Disable IRQ on V2H. */
+	if (priv->model == RCAR_GYROADC_MODEL_R8A7792)
+		writel(0, priv->regs + RCAR_GYROADC_INTENR);
+
+	/* Set mode and timing. */
+	writel(priv->mode, priv->regs + RCAR_GYROADC_MODE_SELECT);
+	writel(clk_len, priv->regs + RCAR_GYROADC_CLOCK_LENGTH);
+	writel(clk_mhz * 1250, priv->regs + RCAR_GYROADC_1_25MS_LENGTH);
+}
+
+static void rcar_gyroadc_hw_start(struct rcar_gyroadc *priv)
+{
+	/* Start sampling. */
+	writel(RCAR_GYROADC_START_STOP_START,
+	       priv->regs + RCAR_GYROADC_START_STOP);
+
+	/*
+	 * Wait for the first conversion to complete. This is longer than
+	 * the 1.25 mS in the datasheet because 1.25 mS is not enough for
+	 * the hardware to deliver the first sample and the hardware does
+	 * then return zeroes instead of valid data.
+	 */
+	mdelay(3);
+}
+
+static void rcar_gyroadc_hw_stop(struct rcar_gyroadc *priv)
+{
+	/* Stop the GyroADC. */
+	writel(0, priv->regs + RCAR_GYROADC_START_STOP);
+}
+
+#define RCAR_GYROADC_CHAN(_idx) {				\
+	.type			= IIO_VOLTAGE,			\
+	.indexed		= 1,				\
+	.channel		= (_idx),			\
+	.info_mask_separate	= BIT(IIO_CHAN_INFO_RAW) |	\
+				  BIT(IIO_CHAN_INFO_SCALE),	\
+	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SAMP_FREQ), \
+}
+
+static const struct iio_chan_spec rcar_gyroadc_iio_channels_1[] = {
+	RCAR_GYROADC_CHAN(0),
+	RCAR_GYROADC_CHAN(1),
+	RCAR_GYROADC_CHAN(2),
+	RCAR_GYROADC_CHAN(3),
+};
+
+static const struct iio_chan_spec rcar_gyroadc_iio_channels_2[] = {
+	RCAR_GYROADC_CHAN(0),
+	RCAR_GYROADC_CHAN(1),
+	RCAR_GYROADC_CHAN(2),
+	RCAR_GYROADC_CHAN(3),
+	RCAR_GYROADC_CHAN(4),
+	RCAR_GYROADC_CHAN(5),
+	RCAR_GYROADC_CHAN(6),
+	RCAR_GYROADC_CHAN(7),
+};
+
+static const struct iio_chan_spec rcar_gyroadc_iio_channels_3[] = {
+	RCAR_GYROADC_CHAN(0),
+	RCAR_GYROADC_CHAN(1),
+	RCAR_GYROADC_CHAN(2),
+	RCAR_GYROADC_CHAN(3),
+	RCAR_GYROADC_CHAN(4),
+	RCAR_GYROADC_CHAN(5),
+	RCAR_GYROADC_CHAN(6),
+	RCAR_GYROADC_CHAN(7),
+};
+
+static int rcar_gyroadc_set_power(struct rcar_gyroadc *priv, bool on)
+{
+	struct device *dev = priv->dev;
+	int ret;
+
+	if (on) {
+		ret = pm_runtime_get_sync(dev);
+		if (ret < 0)
+			pm_runtime_put_noidle(dev);
+	} else {
+		pm_runtime_mark_last_busy(dev);
+		ret = pm_runtime_put_autosuspend(dev);
+	}
+
+	return ret;
+}
+
+static int rcar_gyroadc_read_raw(struct iio_dev *indio_dev,
+				 struct iio_chan_spec const *chan,
+				 int *val, int *val2, long mask)
+{
+	struct rcar_gyroadc *priv = iio_priv(indio_dev);
+	struct regulator *consumer;
+	unsigned int datareg = RCAR_GYROADC_REALTIME_DATA(chan->channel);
+	unsigned int vref;
+	int ret;
+
+	/*
+	 * MB88101 is special in that it has only single regulator for
+	 * all four channels.
+	 */
+	if (priv->mode == RCAR_GYROADC_MODE_SELECT_1_MB88101A)
+		consumer = priv->vref[0];
+	else
+		consumer = priv->vref[chan->channel];
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		if (chan->type != IIO_VOLTAGE)
+			return -EINVAL;
+
+		/* Channel not connected. */
+		if (!consumer)
+			return -EINVAL;
+
+		ret = iio_device_claim_direct_mode(indio_dev);
+		if (ret)
+			return ret;
+
+		ret = rcar_gyroadc_set_power(priv, true);
+		if (ret < 0) {
+			iio_device_release_direct_mode(indio_dev);
+			return ret;
+		}
+
+		*val = readl(priv->regs + datareg);
+		*val &= BIT(priv->sample_width) - 1;
+
+		ret = rcar_gyroadc_set_power(priv, false);
+		iio_device_release_direct_mode(indio_dev);
+		if (ret < 0)
+			return ret;
+
+		return IIO_VAL_INT;
+	case IIO_CHAN_INFO_SCALE:
+		/* Channel not connected. */
+		if (!consumer)
+			return -EINVAL;
+
+		vref = regulator_get_voltage(consumer);
+		*val = vref / 1000;
+		*val2 = 1 << priv->sample_width;
+
+		return IIO_VAL_FRACTIONAL;
+	case IIO_CHAN_INFO_SAMP_FREQ:
+		*val = RCAR_GYROADC_SAMPLE_RATE;
+
+		return IIO_VAL_INT;
+	default:
+		return -EINVAL;
+	}
+}
+
+static int rcar_gyroadc_reg_access(struct iio_dev *indio_dev,
+				   unsigned int reg, unsigned int writeval,
+				   unsigned int *readval)
+{
+	struct rcar_gyroadc *priv = iio_priv(indio_dev);
+	unsigned int maxreg = RCAR_GYROADC_FIFO_STATUS;
+
+	if (readval == NULL)
+		return -EINVAL;
+
+	if (reg % 4)
+		return -EINVAL;
+
+	/* Handle the V2H case with extra interrupt block. */
+	if (priv->model == RCAR_GYROADC_MODEL_R8A7792)
+		maxreg = RCAR_GYROADC_INTENR;
+
+	if (reg > maxreg)
+		return -EINVAL;
+
+	*readval = readl(priv->regs + reg);
+
+	return 0;
+}
+
+static const struct iio_info rcar_gyroadc_iio_info = {
+	.driver_module		= THIS_MODULE,
+	.read_raw		= rcar_gyroadc_read_raw,
+	.debugfs_reg_access	= rcar_gyroadc_reg_access,
+};
+
+static const struct of_device_id rcar_gyroadc_match[] = {
+	{
+		/* R-Car compatible GyroADC */
+		.compatible	= "renesas,rcar-gyroadc",
+		.data		= (void *)RCAR_GYROADC_MODEL_DEFAULT,
+	}, {
+		/* R-Car V2H specialty with interrupt registers. */
+		.compatible	= "renesas,r8a7792-gyroadc",
+		.data		= (void *)RCAR_GYROADC_MODEL_R8A7792,
+	}, {
+		/* sentinel */
+	}
+};
+
+MODULE_DEVICE_TABLE(of, rcar_gyroadc_match);
+
+static const struct of_device_id rcar_gyroadc_child_match[] = {
+	/* Mode 1 ADCs */
+	{
+		.compatible	= "fujitsu,mb88101a",
+		.data		= (void *)RCAR_GYROADC_MODE_SELECT_1_MB88101A,
+	},
+	/* Mode 2 ADCs */
+	{
+		.compatible	= "ti,adcs7476",
+		.data		= (void *)RCAR_GYROADC_MODE_SELECT_2_ADCS7476,
+	}, {
+		.compatible	= "ti,adc121",
+		.data		= (void *)RCAR_GYROADC_MODE_SELECT_2_ADCS7476,
+	}, {
+		.compatible	= "adi,ad7476",
+		.data		= (void *)RCAR_GYROADC_MODE_SELECT_2_ADCS7476,
+	},
+	/* Mode 3 ADCs */
+	{
+		.compatible	= "maxim,max1162",
+		.data		= (void *)RCAR_GYROADC_MODE_SELECT_3_MAX1162,
+	}, {
+		.compatible	= "maxim,max11100",
+		.data		= (void *)RCAR_GYROADC_MODE_SELECT_3_MAX1162,
+	},
+	{ /* sentinel */ }
+};
+
+static int rcar_gyroadc_parse_subdevs(struct iio_dev *indio_dev)
+{
+	const struct of_device_id *of_id;
+	const struct iio_chan_spec *channels;
+	struct rcar_gyroadc *priv = iio_priv(indio_dev);
+	struct device *dev = priv->dev;
+	struct device_node *np = dev->of_node;
+	struct device_node *child;
+	struct regulator *vref;
+	unsigned int reg;
+	unsigned int adcmode, childmode;
+	unsigned int sample_width;
+	unsigned int num_channels;
+	int ret, first = 1;
+
+	for_each_child_of_node(np, child) {
+		of_id = of_match_node(rcar_gyroadc_child_match, child);
+		if (!of_id) {
+			dev_err(dev, "Ignoring unsupported ADC \"%s\".",
+				child->name);
+			continue;
+		}
+
+		childmode = (unsigned int)of_id->data;
+		switch (childmode) {
+		case RCAR_GYROADC_MODE_SELECT_1_MB88101A:
+			sample_width = 12;
+			channels = rcar_gyroadc_iio_channels_1;
+			num_channels = ARRAY_SIZE(rcar_gyroadc_iio_channels_1);
+			break;
+		case RCAR_GYROADC_MODE_SELECT_2_ADCS7476:
+			sample_width = 15;
+			channels = rcar_gyroadc_iio_channels_2;
+			num_channels = ARRAY_SIZE(rcar_gyroadc_iio_channels_2);
+			break;
+		case RCAR_GYROADC_MODE_SELECT_3_MAX1162:
+			sample_width = 16;
+			channels = rcar_gyroadc_iio_channels_3;
+			num_channels = ARRAY_SIZE(rcar_gyroadc_iio_channels_3);
+			break;
+		}
+
+		/*
+		 * MB88101 is special in that it's only a single chip taking
+		 * up all the CHS lines. Thus, the DT binding is also special
+		 * and has no reg property. If we run into such ADC, handle
+		 * it here.
+		 */
+		if (childmode == RCAR_GYROADC_MODE_SELECT_1_MB88101A) {
+			reg = 0;
+		} else {
+			ret = of_property_read_u32(child, "reg", &reg);
+			if (ret) {
+				dev_err(dev,
+					"Failed to get child reg property of ADC \"%s\".\n",
+					child->name);
+				return ret;
+			}
+
+			/* Channel number is too high. */
+			if (reg >= num_channels) {
+				dev_err(dev,
+					"Only %i channels supported with %s, but reg = <%i>.\n",
+					num_channels, child->name, reg);
+				return ret;
+			}
+		}
+
+		/* Child node selected different mode than the rest. */
+		if (!first && (adcmode != childmode)) {
+			dev_err(dev,
+				"Channel %i uses different ADC mode than the rest.\n",
+				reg);
+			return ret;
+		}
+
+		/* Channel is valid, grab the regulator. */
+		dev->of_node = child;
+		vref = devm_regulator_get(dev, "vref");
+		dev->of_node = np;
+		if (IS_ERR(vref)) {
+			dev_dbg(dev, "Channel %i 'vref' supply not connected.\n",
+				reg);
+			return PTR_ERR(vref);
+		}
+
+		priv->vref[reg] = vref;
+
+		if (!first)
+			continue;
+
+		/* First child node which passed sanity tests. */
+		adcmode = childmode;
+		first = 0;
+
+		priv->num_channels = num_channels;
+		priv->mode = childmode;
+		priv->sample_width = sample_width;
+
+		indio_dev->channels = channels;
+		indio_dev->num_channels = num_channels;
+
+		/*
+		 * MB88101 is special and we only have one such device
+		 * attached to the GyroADC at a time, so if we found it,
+		 * we can stop parsing here.
+		 */
+		if (childmode == RCAR_GYROADC_MODE_SELECT_1_MB88101A)
+			break;
+	}
+
+	if (first) {
+		dev_err(dev, "No valid ADC channels found, aborting.\n");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static void rcar_gyroadc_deinit_supplies(struct iio_dev *indio_dev)
+{
+	struct rcar_gyroadc *priv = iio_priv(indio_dev);
+	unsigned int i;
+
+	for (i = 0; i < priv->num_channels; i++) {
+		if (!priv->vref[i])
+			continue;
+
+		regulator_disable(priv->vref[i]);
+	}
+}
+
+static int rcar_gyroadc_init_supplies(struct iio_dev *indio_dev)
+{
+	struct rcar_gyroadc *priv = iio_priv(indio_dev);
+	struct device *dev = priv->dev;
+	unsigned int i;
+	int ret;
+
+	for (i = 0; i < priv->num_channels; i++) {
+		if (!priv->vref[i])
+			continue;
+
+		ret = regulator_enable(priv->vref[i]);
+		if (ret) {
+			dev_err(dev, "Failed to enable regulator %i (ret=%i)\n",
+				i, ret);
+			goto err;
+		}
+	}
+
+	return 0;
+
+err:
+	rcar_gyroadc_deinit_supplies(indio_dev);
+	return ret;
+}
+
+static int rcar_gyroadc_probe(struct platform_device *pdev)
+{
+	const struct of_device_id *of_id =
+		of_match_device(rcar_gyroadc_match, &pdev->dev);
+	struct device *dev = &pdev->dev;
+	struct rcar_gyroadc *priv;
+	struct iio_dev *indio_dev;
+	struct resource *mem;
+	int ret;
+
+	indio_dev = devm_iio_device_alloc(dev, sizeof(*priv));
+	if (!indio_dev) {
+		dev_err(dev, "Failed to allocate IIO device.\n");
+		return -ENOMEM;
+	}
+
+	priv = iio_priv(indio_dev);
+	priv->dev = dev;
+
+	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	priv->regs = devm_ioremap_resource(dev, mem);
+	if (IS_ERR(priv->regs))
+		return PTR_ERR(priv->regs);
+
+	priv->iclk = devm_clk_get(dev, "if");
+	if (IS_ERR(priv->iclk)) {
+		ret = PTR_ERR(priv->iclk);
+		if (ret != -EPROBE_DEFER)
+			dev_err(dev, "Failed to get IF clock (ret=%i)\n", ret);
+		return ret;
+	}
+
+	ret = rcar_gyroadc_parse_subdevs(indio_dev);
+	if (ret)
+		return ret;
+
+	ret = rcar_gyroadc_init_supplies(indio_dev);
+	if (ret)
+		return ret;
+
+	priv->model = (enum rcar_gyroadc_model)of_id->data;
+
+	platform_set_drvdata(pdev, indio_dev);
+
+	indio_dev->name = DRIVER_NAME;
+	indio_dev->dev.parent = dev;
+	indio_dev->dev.of_node = pdev->dev.of_node;
+	indio_dev->info = &rcar_gyroadc_iio_info;
+	indio_dev->modes = INDIO_DIRECT_MODE;
+
+	ret = clk_prepare_enable(priv->iclk);
+	if (ret) {
+		dev_err(dev, "Could not prepare or enable the IF clock.\n");
+		goto err_clk_if_enable;
+	}
+
+	pm_runtime_set_autosuspend_delay(dev, RCAR_GYROADC_RUNTIME_PM_DELAY_MS);
+	pm_runtime_use_autosuspend(dev);
+	pm_runtime_enable(dev);
+
+	pm_runtime_get_sync(dev);
+	rcar_gyroadc_hw_init(priv);
+	rcar_gyroadc_hw_start(priv);
+
+	ret = iio_device_register(indio_dev);
+	if (ret) {
+		dev_err(dev, "Couldn't register IIO device.\n");
+		goto err_iio_device_register;
+	}
+
+	pm_runtime_put_sync(dev);
+
+	return 0;
+
+err_iio_device_register:
+	rcar_gyroadc_hw_stop(priv);
+	pm_runtime_put_sync(dev);
+	pm_runtime_disable(dev);
+	pm_runtime_set_suspended(dev);
+	clk_disable_unprepare(priv->iclk);
+err_clk_if_enable:
+	rcar_gyroadc_deinit_supplies(indio_dev);
+
+	return ret;
+}
+
+static int rcar_gyroadc_remove(struct platform_device *pdev)
+{
+	struct iio_dev *indio_dev = platform_get_drvdata(pdev);
+	struct rcar_gyroadc *priv = iio_priv(indio_dev);
+	struct device *dev = priv->dev;
+
+	iio_device_unregister(indio_dev);
+	pm_runtime_get_sync(dev);
+	rcar_gyroadc_hw_stop(priv);
+	pm_runtime_put_sync(dev);
+	pm_runtime_disable(dev);
+	pm_runtime_set_suspended(dev);
+	clk_disable_unprepare(priv->iclk);
+	rcar_gyroadc_deinit_supplies(indio_dev);
+
+	return 0;
+}
+
+#if defined(CONFIG_PM)
+static int rcar_gyroadc_suspend(struct device *dev)
+{
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	struct rcar_gyroadc *priv = iio_priv(indio_dev);
+
+	rcar_gyroadc_hw_stop(priv);
+
+	return 0;
+}
+
+static int rcar_gyroadc_resume(struct device *dev)
+{
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	struct rcar_gyroadc *priv = iio_priv(indio_dev);
+
+	rcar_gyroadc_hw_start(priv);
+
+	return 0;
+}
+#endif
+
+static const struct dev_pm_ops rcar_gyroadc_pm_ops = {
+	SET_RUNTIME_PM_OPS(rcar_gyroadc_suspend, rcar_gyroadc_resume, NULL)
+};
+
+static struct platform_driver rcar_gyroadc_driver = {
+	.probe          = rcar_gyroadc_probe,
+	.remove         = rcar_gyroadc_remove,
+	.driver         = {
+		.name		= DRIVER_NAME,
+		.of_match_table	= rcar_gyroadc_match,
+		.pm		= &rcar_gyroadc_pm_ops,
+	},
+};
+
+module_platform_driver(rcar_gyroadc_driver);
+
+MODULE_AUTHOR("Marek Vasut <[email protected]>");
+MODULE_DESCRIPTION("Renesas R-Car GyroADC driver");
+MODULE_LICENSE("GPL");