iio: adc: add support for Berlin

This patch adds the support of the Berlin ADC, available on Berlin SoCs.
This ADC has 8 channels available, with one connected to a temperature
sensor.

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

Signed-off-by: Antoine Tenart <antoine.tenart@free-electrons.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

3 files changed, 386 insertions, 0 deletions

diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
index e36a73e7c3a8..cee50de76fb1 100644
--- a/drivers/iio/adc/Kconfig
+++ b/drivers/iio/adc/Kconfig
@@ -135,6 +135,13 @@ config AXP288_ADC
 	  device. Depending on platform configuration, this general purpose ADC can
 	  be used for sampling sensors such as thermal resistors.
 
+config BERLIN2_ADC
+	tristate "Marvell Berlin2 ADC driver"
+	depends on ARCH_BERLIN
+	help
+	  Marvell Berlin2 ADC driver. This ADC has 8 channels, with one used for
+	  temperature measurement.
+
 config DA9150_GPADC
 	tristate "Dialog DA9150 GPADC driver support"
 	depends on MFD_DA9150
diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
index 3930e63e84bc..a0962103e866 100644
--- a/drivers/iio/adc/Makefile
+++ b/drivers/iio/adc/Makefile
@@ -15,6 +15,7 @@ obj-$(CONFIG_AD7887) += ad7887.o
 obj-$(CONFIG_AD799X) += ad799x.o
 obj-$(CONFIG_AT91_ADC) += at91_adc.o
 obj-$(CONFIG_AXP288_ADC) += axp288_adc.o
+obj-$(CONFIG_BERLIN2_ADC) += berlin2-adc.o
 obj-$(CONFIG_DA9150_GPADC) += da9150-gpadc.o
 obj-$(CONFIG_CC10001_ADC) += cc10001_adc.o
 obj-$(CONFIG_EXYNOS_ADC) += exynos_adc.o
diff --git a/drivers/iio/adc/berlin2-adc.c b/drivers/iio/adc/berlin2-adc.c
new file mode 100644
index 000000000000..aecc9ad995ad
--- /dev/null
+++ b/drivers/iio/adc/berlin2-adc.c
@@ -0,0 +1,378 @@
+/*
+ * Marvell Berlin2 ADC driver
+ *
+ * Copyright (C) 2015 Marvell Technology Group Ltd.
+ *
+ * Antoine Tenart <antoine.tenart@free-electrons.com>
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2. This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+
+#include <linux/iio/iio.h>
+#include <linux/iio/driver.h>
+#include <linux/iio/machine.h>
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/mfd/syscon.h>
+#include <linux/regmap.h>
+#include <linux/sched.h>
+#include <linux/wait.h>
+
+#define BERLIN2_SM_CTRL				0x14
+#define  BERLIN2_SM_CTRL_SM_SOC_INT		BIT(1)
+#define  BERLIN2_SM_CTRL_SOC_SM_INT		BIT(2)
+#define  BERLIN2_SM_CTRL_ADC_SEL(x)		(BIT(x) << 5)	/* 0-15 */
+#define  BERLIN2_SM_CTRL_ADC_SEL_MASK		(0xf << 5)
+#define  BERLIN2_SM_CTRL_ADC_POWER		BIT(9)
+#define  BERLIN2_SM_CTRL_ADC_CLKSEL_DIV2	(0x0 << 10)
+#define  BERLIN2_SM_CTRL_ADC_CLKSEL_DIV3	(0x1 << 10)
+#define  BERLIN2_SM_CTRL_ADC_CLKSEL_DIV4	(0x2 << 10)
+#define  BERLIN2_SM_CTRL_ADC_CLKSEL_DIV8	(0x3 << 10)
+#define  BERLIN2_SM_CTRL_ADC_CLKSEL_MASK	(0x3 << 10)
+#define  BERLIN2_SM_CTRL_ADC_START		BIT(12)
+#define  BERLIN2_SM_CTRL_ADC_RESET		BIT(13)
+#define  BERLIN2_SM_CTRL_ADC_BANDGAP_RDY	BIT(14)
+#define  BERLIN2_SM_CTRL_ADC_CONT_SINGLE	(0x0 << 15)
+#define  BERLIN2_SM_CTRL_ADC_CONT_CONTINUOUS	(0x1 << 15)
+#define  BERLIN2_SM_CTRL_ADC_BUFFER_EN		BIT(16)
+#define  BERLIN2_SM_CTRL_ADC_VREF_EXT		(0x0 << 17)
+#define  BERLIN2_SM_CTRL_ADC_VREF_INT		(0x1 << 17)
+#define  BERLIN2_SM_CTRL_ADC_ROTATE		BIT(19)
+#define  BERLIN2_SM_CTRL_TSEN_EN		BIT(20)
+#define  BERLIN2_SM_CTRL_TSEN_CLK_SEL_125	(0x0 << 21)	/* 1.25 MHz */
+#define  BERLIN2_SM_CTRL_TSEN_CLK_SEL_250	(0x1 << 21)	/* 2.5 MHz */
+#define  BERLIN2_SM_CTRL_TSEN_MODE_0_125	(0x0 << 22)	/* 0-125 C */
+#define  BERLIN2_SM_CTRL_TSEN_MODE_10_50	(0x1 << 22)	/* 10-50 C */
+#define  BERLIN2_SM_CTRL_TSEN_RESET		BIT(29)
+#define BERLIN2_SM_ADC_DATA			0x20
+#define  BERLIN2_SM_ADC_MASK			0x3ff
+#define BERLIN2_SM_ADC_STATUS			0x1c
+#define  BERLIN2_SM_ADC_STATUS_DATA_RDY(x)	BIT(x)		/* 0-15 */
+#define  BERLIN2_SM_ADC_STATUS_DATA_RDY_MASK	0xf
+#define  BERLIN2_SM_ADC_STATUS_INT_EN(x)	(BIT(x) << 16)	/* 0-15 */
+#define  BERLIN2_SM_ADC_STATUS_INT_EN_MASK	(0xf << 16)
+#define BERLIN2_SM_TSEN_STATUS			0x24
+#define  BERLIN2_SM_TSEN_STATUS_DATA_RDY	BIT(0)
+#define  BERLIN2_SM_TSEN_STATUS_INT_EN		BIT(1)
+#define BERLIN2_SM_TSEN_DATA			0x28
+#define  BERLIN2_SM_TSEN_MASK			0xfff
+#define BERLIN2_SM_TSEN_CTRL			0x74
+#define  BERLIN2_SM_TSEN_CTRL_START		BIT(8)
+#define  BERLIN2_SM_TSEN_CTRL_SETTLING_4	(0x0 << 21)	/* 4 us */
+#define  BERLIN2_SM_TSEN_CTRL_SETTLING_12	(0x1 << 21)	/* 12 us */
+#define  BERLIN2_SM_TSEN_CTRL_SETTLING_MASK	(0x1 << 21)
+#define  BERLIN2_SM_TSEN_CTRL_TRIM(x)		((x) << 22)
+#define  BERLIN2_SM_TSEN_CTRL_TRIM_MASK		(0xf << 22)
+
+struct berlin2_adc_priv {
+	struct regmap		*regmap;
+	struct mutex		lock;
+	wait_queue_head_t	wq;
+	bool			data_available;
+	int			data;
+};
+
+#define BERLIN2_ADC_CHANNEL(n, t)					\
+		{							\
+			.channel	= n,				\
+			.datasheet_name	= "channel"#n,			\
+			.type		= t,				\
+			.indexed	= 1,				\
+			.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),	\
+		}
+
+static struct iio_chan_spec berlin2_adc_channels[] = {
+	BERLIN2_ADC_CHANNEL(0, IIO_VOLTAGE),	/* external input */
+	BERLIN2_ADC_CHANNEL(1, IIO_VOLTAGE),	/* external input */
+	BERLIN2_ADC_CHANNEL(2, IIO_VOLTAGE),	/* external input */
+	BERLIN2_ADC_CHANNEL(3, IIO_VOLTAGE),	/* external input */
+	BERLIN2_ADC_CHANNEL(4, IIO_VOLTAGE),	/* reserved */
+	BERLIN2_ADC_CHANNEL(5, IIO_VOLTAGE),	/* reserved */
+	{					/* temperature sensor */
+		.channel		= 6,
+		.datasheet_name		= "channel6",
+		.type			= IIO_TEMP,
+		.indexed		= 0,
+		.info_mask_separate	= BIT(IIO_CHAN_INFO_PROCESSED),
+	},
+	BERLIN2_ADC_CHANNEL(7, IIO_VOLTAGE),	/* reserved */
+	IIO_CHAN_SOFT_TIMESTAMP(8),		/* timestamp */
+};
+#define BERLIN2_N_CHANNELS	ARRAY_SIZE(berlin2_adc_channels)
+
+static int berlin2_adc_read(struct iio_dev *indio_dev, int channel)
+{
+	struct berlin2_adc_priv *priv = iio_priv(indio_dev);
+	int data, ret;
+
+	mutex_lock(&priv->lock);
+
+	/* Configure the ADC */
+	regmap_update_bits(priv->regmap, BERLIN2_SM_CTRL,
+			BERLIN2_SM_CTRL_ADC_RESET | BERLIN2_SM_CTRL_ADC_SEL_MASK
+			| BERLIN2_SM_CTRL_ADC_START,
+			BERLIN2_SM_CTRL_ADC_SEL(channel) | BERLIN2_SM_CTRL_ADC_START);
+
+	ret = wait_event_interruptible_timeout(priv->wq, priv->data_available,
+			msecs_to_jiffies(1000));
+
+	/* Disable the interrupts */
+	regmap_update_bits(priv->regmap, BERLIN2_SM_ADC_STATUS,
+			BERLIN2_SM_ADC_STATUS_INT_EN(channel), 0);
+
+	if (ret == 0)
+		ret = -ETIMEDOUT;
+	if (ret < 0) {
+		mutex_unlock(&priv->lock);
+		return ret;
+	}
+
+	regmap_update_bits(priv->regmap, BERLIN2_SM_CTRL,
+			BERLIN2_SM_CTRL_ADC_START, 0);
+
+	data = priv->data;
+	priv->data_available = false;
+
+	mutex_unlock(&priv->lock);
+
+	return data;
+}
+
+static int berlin2_adc_tsen_read(struct iio_dev *indio_dev)
+{
+	struct berlin2_adc_priv *priv = iio_priv(indio_dev);
+	int data, ret;
+
+	mutex_lock(&priv->lock);
+
+	/* Configure the ADC */
+	regmap_update_bits(priv->regmap, BERLIN2_SM_CTRL,
+			BERLIN2_SM_CTRL_TSEN_RESET | BERLIN2_SM_CTRL_ADC_ROTATE,
+			BERLIN2_SM_CTRL_ADC_ROTATE);
+
+	/* Configure the temperature sensor */
+	regmap_update_bits(priv->regmap, BERLIN2_SM_TSEN_CTRL,
+			BERLIN2_SM_TSEN_CTRL_TRIM_MASK | BERLIN2_SM_TSEN_CTRL_SETTLING_MASK
+			| BERLIN2_SM_TSEN_CTRL_START,
+			BERLIN2_SM_TSEN_CTRL_TRIM(3) | BERLIN2_SM_TSEN_CTRL_SETTLING_12
+			| BERLIN2_SM_TSEN_CTRL_START);
+
+	ret = wait_event_interruptible_timeout(priv->wq, priv->data_available,
+			msecs_to_jiffies(1000));
+
+	/* Disable interrupts */
+	regmap_update_bits(priv->regmap, BERLIN2_SM_TSEN_STATUS,
+			BERLIN2_SM_TSEN_STATUS_INT_EN, 0);
+
+	if (ret == 0)
+		ret = -ETIMEDOUT;
+	if (ret < 0) {
+		mutex_unlock(&priv->lock);
+		return ret;
+	}
+
+	regmap_update_bits(priv->regmap, BERLIN2_SM_TSEN_CTRL,
+			BERLIN2_SM_TSEN_CTRL_START, 0);
+
+	data = priv->data;
+	priv->data_available = false;
+
+	mutex_unlock(&priv->lock);
+
+	return data;
+}
+
+static int berlin2_adc_read_raw(struct iio_dev *indio_dev,
+		struct iio_chan_spec const *chan, int *val, int *val2,
+		long mask)
+{
+	struct berlin2_adc_priv *priv = iio_priv(indio_dev);
+	int temp;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		if (chan->type != IIO_VOLTAGE)
+			return -EINVAL;
+
+		/* Enable the interrupts */
+		regmap_write(priv->regmap, BERLIN2_SM_ADC_STATUS,
+				BERLIN2_SM_ADC_STATUS_INT_EN(chan->channel));
+
+		*val = berlin2_adc_read(indio_dev, chan->channel);
+		if (*val < 0)
+			return *val;
+
+		return IIO_VAL_INT;
+	case IIO_CHAN_INFO_PROCESSED:
+		if (chan->type != IIO_TEMP)
+			return -EINVAL;
+
+		/* Enable interrupts */
+		regmap_write(priv->regmap, BERLIN2_SM_TSEN_STATUS,
+				BERLIN2_SM_TSEN_STATUS_INT_EN);
+
+		temp = berlin2_adc_tsen_read(indio_dev);
+		if (temp < 0)
+			return temp;
+
+		if (temp > 2047)
+			temp = -(4096 - temp);
+
+		/* Convert to milli Celsius */
+		*val = ((temp * 100000) / 264 - 270000);
+		return IIO_VAL_INT;
+	default:
+		break;
+	}
+
+	return -EINVAL;
+}
+
+static irqreturn_t berlin2_adc_irq(int irq, void *private)
+{
+	struct berlin2_adc_priv *priv = iio_priv(private);
+	unsigned val;
+
+	regmap_read(priv->regmap, BERLIN2_SM_ADC_STATUS, &val);
+	if (val & BERLIN2_SM_ADC_STATUS_DATA_RDY_MASK) {
+		regmap_read(priv->regmap, BERLIN2_SM_ADC_DATA, &priv->data);
+		priv->data &= BERLIN2_SM_ADC_MASK;
+
+		val &= ~BERLIN2_SM_ADC_STATUS_DATA_RDY_MASK;
+		regmap_write(priv->regmap, BERLIN2_SM_ADC_STATUS, val);
+
+		priv->data_available = true;
+		wake_up_interruptible(&priv->wq);
+	}
+
+	return IRQ_HANDLED;
+}
+
+static irqreturn_t berlin2_adc_tsen_irq(int irq, void *private)
+{
+	struct berlin2_adc_priv *priv = iio_priv(private);
+	unsigned val;
+
+	regmap_read(priv->regmap, BERLIN2_SM_TSEN_STATUS, &val);
+	if (val & BERLIN2_SM_TSEN_STATUS_DATA_RDY) {
+		regmap_read(priv->regmap, BERLIN2_SM_TSEN_DATA, &priv->data);
+		priv->data &= BERLIN2_SM_TSEN_MASK;
+
+		val &= ~BERLIN2_SM_TSEN_STATUS_DATA_RDY;
+		regmap_write(priv->regmap, BERLIN2_SM_TSEN_STATUS, val);
+
+		priv->data_available = true;
+		wake_up_interruptible(&priv->wq);
+	}
+
+	return IRQ_HANDLED;
+}
+
+static const struct iio_info berlin2_adc_info = {
+	.driver_module	= THIS_MODULE,
+	.read_raw	= berlin2_adc_read_raw,
+};
+
+static int berlin2_adc_probe(struct platform_device *pdev)
+{
+	struct iio_dev *indio_dev;
+	struct berlin2_adc_priv *priv;
+	struct device_node *parent_np = of_get_parent(pdev->dev.of_node);
+	int irq, tsen_irq;
+	int ret;
+
+	indio_dev = devm_iio_device_alloc(&pdev->dev,
+					  sizeof(struct berlin2_adc_priv));
+	if (!indio_dev)
+		return -ENOMEM;
+
+	priv = iio_priv(indio_dev);
+	platform_set_drvdata(pdev, indio_dev);
+
+	priv->regmap = syscon_node_to_regmap(parent_np);
+	of_node_put(parent_np);
+	if (IS_ERR(priv->regmap))
+		return PTR_ERR(priv->regmap);
+
+	irq = platform_get_irq_byname(pdev, "adc");
+	if (irq < 0)
+		return -ENODEV;
+
+	tsen_irq = platform_get_irq_byname(pdev, "tsen");
+	if (tsen_irq < 0)
+		return -ENODEV;
+
+	ret = devm_request_irq(&pdev->dev, irq, berlin2_adc_irq, 0,
+			pdev->dev.driver->name, indio_dev);
+	if (ret)
+		return ret;
+
+	ret = devm_request_irq(&pdev->dev, tsen_irq, berlin2_adc_tsen_irq,
+			0, pdev->dev.driver->name, indio_dev);
+	if (ret)
+		return ret;
+
+	init_waitqueue_head(&priv->wq);
+	mutex_init(&priv->lock);
+
+	indio_dev->dev.parent = &pdev->dev;
+	indio_dev->name = dev_name(&pdev->dev);
+	indio_dev->modes = INDIO_DIRECT_MODE;
+	indio_dev->info = &berlin2_adc_info;
+
+	indio_dev->num_channels = BERLIN2_N_CHANNELS;
+	indio_dev->channels = berlin2_adc_channels;
+
+	/* Power up the ADC */
+	regmap_update_bits(priv->regmap, BERLIN2_SM_CTRL,
+			BERLIN2_SM_CTRL_ADC_POWER, BERLIN2_SM_CTRL_ADC_POWER);
+
+	ret = iio_device_register(indio_dev);
+	if (ret) {
+		/* Power down the ADC */
+		regmap_update_bits(priv->regmap, BERLIN2_SM_CTRL,
+				BERLIN2_SM_CTRL_ADC_POWER, 0);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int berlin2_adc_remove(struct platform_device *pdev)
+{
+	struct iio_dev *indio_dev = platform_get_drvdata(pdev);
+	struct berlin2_adc_priv *priv = iio_priv(indio_dev);
+
+	iio_device_unregister(indio_dev);
+
+	/* Power down the ADC */
+	regmap_update_bits(priv->regmap, BERLIN2_SM_CTRL,
+			BERLIN2_SM_CTRL_ADC_POWER, 0);
+
+	return 0;
+}
+
+static const struct of_device_id berlin2_adc_match[] = {
+	{ .compatible = "marvell,berlin2-adc", },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, berlin2_adc_match);
+
+static struct platform_driver berlin2_adc_driver = {
+	.driver	= {
+		.name		= "berlin2-adc",
+		.of_match_table	= berlin2_adc_match,
+	},
+	.probe	= berlin2_adc_probe,
+	.remove	= berlin2_adc_remove,
+};
+module_platform_driver(berlin2_adc_driver);
+
+MODULE_AUTHOR("Antoine Tenart <antoine.tenart@free-electrons.com>");
+MODULE_DESCRIPTION("Marvell Berlin2 ADC driver");
+MODULE_LICENSE("GPL v2");