Adding upstream version 4.19.249.upstream/4.19.249upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 959 insertions, 0 deletions

diff --git a/drivers/iio/magnetometer/ak8974.c b/drivers/iio/magnetometer/ak8974.c
new file mode 100644
index 000000000..d3f09405c
--- /dev/null
+++ b/drivers/iio/magnetometer/ak8974.c
@@ -0,0 +1,959 @@
+/*
+ * Driver for the Asahi Kasei EMD Corporation AK8974
+ * and Aichi Steel AMI305 magnetometer chips.
+ * Based on a patch from Samu Onkalo and the AK8975 IIO driver.
+ *
+ * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies).
+ * Copyright (c) 2010 NVIDIA Corporation.
+ * Copyright (C) 2016 Linaro Ltd.
+ *
+ * Author: Samu Onkalo <samu.p.onkalo@nokia.com>
+ * Author: Linus Walleij <linus.walleij@linaro.org>
+ */
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/i2c.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h> /* For irq_get_irq_data() */
+#include <linux/completion.h>
+#include <linux/err.h>
+#include <linux/mutex.h>
+#include <linux/delay.h>
+#include <linux/bitops.h>
+#include <linux/random.h>
+#include <linux/regmap.h>
+#include <linux/regulator/consumer.h>
+#include <linux/pm_runtime.h>
+
+#include <linux/iio/iio.h>
+#include <linux/iio/sysfs.h>
+#include <linux/iio/buffer.h>
+#include <linux/iio/trigger.h>
+#include <linux/iio/trigger_consumer.h>
+#include <linux/iio/triggered_buffer.h>
+
+/*
+ * 16-bit registers are little-endian. LSB is at the address defined below
+ * and MSB is at the next higher address.
+ */
+
+/* These registers are common for AK8974 and AMI30x */
+#define AK8974_SELFTEST		0x0C
+#define AK8974_SELFTEST_IDLE	0x55
+#define AK8974_SELFTEST_OK	0xAA
+
+#define AK8974_INFO		0x0D
+
+#define AK8974_WHOAMI		0x0F
+#define AK8974_WHOAMI_VALUE_AMI306 0x46
+#define AK8974_WHOAMI_VALUE_AMI305 0x47
+#define AK8974_WHOAMI_VALUE_AK8974 0x48
+
+#define AK8974_DATA_X		0x10
+#define AK8974_DATA_Y		0x12
+#define AK8974_DATA_Z		0x14
+#define AK8974_INT_SRC		0x16
+#define AK8974_STATUS		0x18
+#define AK8974_INT_CLEAR	0x1A
+#define AK8974_CTRL1		0x1B
+#define AK8974_CTRL2		0x1C
+#define AK8974_CTRL3		0x1D
+#define AK8974_INT_CTRL		0x1E
+#define AK8974_INT_THRES	0x26  /* Absolute any axis value threshold */
+#define AK8974_PRESET		0x30
+
+/* AK8974-specific offsets */
+#define AK8974_OFFSET_X		0x20
+#define AK8974_OFFSET_Y		0x22
+#define AK8974_OFFSET_Z		0x24
+/* AMI305-specific offsets */
+#define AMI305_OFFSET_X		0x6C
+#define AMI305_OFFSET_Y		0x72
+#define AMI305_OFFSET_Z		0x78
+
+/* Different temperature registers */
+#define AK8974_TEMP		0x31
+#define AMI305_TEMP		0x60
+
+/* AMI306-specific control register */
+#define AMI306_CTRL4		0x5C
+
+/* AMI306 factory calibration data */
+
+/* fine axis sensitivity */
+#define AMI306_FINEOUTPUT_X	0x90
+#define AMI306_FINEOUTPUT_Y	0x92
+#define AMI306_FINEOUTPUT_Z	0x94
+
+/* axis sensitivity */
+#define AMI306_SENS_X		0x96
+#define AMI306_SENS_Y		0x98
+#define AMI306_SENS_Z		0x9A
+
+/* axis cross-interference */
+#define AMI306_GAIN_PARA_XZ	0x9C
+#define AMI306_GAIN_PARA_XY	0x9D
+#define AMI306_GAIN_PARA_YZ	0x9E
+#define AMI306_GAIN_PARA_YX	0x9F
+#define AMI306_GAIN_PARA_ZY	0xA0
+#define AMI306_GAIN_PARA_ZX	0xA1
+
+/* offset at ZERO magnetic field */
+#define AMI306_OFFZERO_X	0xF8
+#define AMI306_OFFZERO_Y	0xFA
+#define AMI306_OFFZERO_Z	0xFC
+
+
+#define AK8974_INT_X_HIGH	BIT(7) /* Axis over +threshold  */
+#define AK8974_INT_Y_HIGH	BIT(6)
+#define AK8974_INT_Z_HIGH	BIT(5)
+#define AK8974_INT_X_LOW	BIT(4) /* Axis below -threshold	*/
+#define AK8974_INT_Y_LOW	BIT(3)
+#define AK8974_INT_Z_LOW	BIT(2)
+#define AK8974_INT_RANGE	BIT(1) /* Range overflow (any axis) */
+
+#define AK8974_STATUS_DRDY	BIT(6) /* Data ready */
+#define AK8974_STATUS_OVERRUN	BIT(5) /* Data overrun */
+#define AK8974_STATUS_INT	BIT(4) /* Interrupt occurred */
+
+#define AK8974_CTRL1_POWER	BIT(7) /* 0 = standby; 1 = active */
+#define AK8974_CTRL1_RATE	BIT(4) /* 0 = 10 Hz; 1 = 20 Hz	 */
+#define AK8974_CTRL1_FORCE_EN	BIT(1) /* 0 = normal; 1 = force	 */
+#define AK8974_CTRL1_MODE2	BIT(0) /* 0 */
+
+#define AK8974_CTRL2_INT_EN	BIT(4)  /* 1 = enable interrupts	      */
+#define AK8974_CTRL2_DRDY_EN	BIT(3)  /* 1 = enable data ready signal */
+#define AK8974_CTRL2_DRDY_POL	BIT(2)  /* 1 = data ready active high   */
+#define AK8974_CTRL2_RESDEF	(AK8974_CTRL2_DRDY_POL)
+
+#define AK8974_CTRL3_RESET	BIT(7) /* Software reset		  */
+#define AK8974_CTRL3_FORCE	BIT(6) /* Start forced measurement */
+#define AK8974_CTRL3_SELFTEST	BIT(4) /* Set selftest register	  */
+#define AK8974_CTRL3_RESDEF	0x00
+
+#define AK8974_INT_CTRL_XEN	BIT(7) /* Enable interrupt for this axis */
+#define AK8974_INT_CTRL_YEN	BIT(6)
+#define AK8974_INT_CTRL_ZEN	BIT(5)
+#define AK8974_INT_CTRL_XYZEN	(BIT(7)|BIT(6)|BIT(5))
+#define AK8974_INT_CTRL_POL	BIT(3) /* 0 = active low; 1 = active high */
+#define AK8974_INT_CTRL_PULSE	BIT(1) /* 0 = latched; 1 = pulse (50 usec) */
+#define AK8974_INT_CTRL_RESDEF	(AK8974_INT_CTRL_XYZEN | AK8974_INT_CTRL_POL)
+
+/* The AMI305 has elaborate FW version and serial number registers */
+#define AMI305_VER		0xE8
+#define AMI305_SN		0xEA
+
+#define AK8974_MAX_RANGE	2048
+
+#define AK8974_POWERON_DELAY	50
+#define AK8974_ACTIVATE_DELAY	1
+#define AK8974_SELFTEST_DELAY	1
+/*
+ * Set the autosuspend to two orders of magnitude larger than the poweron
+ * delay to make sane reasonable power tradeoff savings (5 seconds in
+ * this case).
+ */
+#define AK8974_AUTOSUSPEND_DELAY 5000
+
+#define AK8974_MEASTIME		3
+
+#define AK8974_PWR_ON		1
+#define AK8974_PWR_OFF		0
+
+/**
+ * struct ak8974 - state container for the AK8974 driver
+ * @i2c: parent I2C client
+ * @orientation: mounting matrix, flipped axis etc
+ * @map: regmap to access the AK8974 registers over I2C
+ * @regs: the avdd and dvdd power regulators
+ * @name: the name of the part
+ * @variant: the whoami ID value (for selecting code paths)
+ * @lock: locks the magnetometer for exclusive use during a measurement
+ * @drdy_irq: uses the DRDY IRQ line
+ * @drdy_complete: completion for DRDY
+ * @drdy_active_low: the DRDY IRQ is active low
+ */
+struct ak8974 {
+	struct i2c_client *i2c;
+	struct iio_mount_matrix orientation;
+	struct regmap *map;
+	struct regulator_bulk_data regs[2];
+	const char *name;
+	u8 variant;
+	struct mutex lock;
+	bool drdy_irq;
+	struct completion drdy_complete;
+	bool drdy_active_low;
+	/* Ensure timestamp is naturally aligned */
+	struct {
+		__le16 channels[3];
+		s64 ts __aligned(8);
+	} scan;
+};
+
+static const char ak8974_reg_avdd[] = "avdd";
+static const char ak8974_reg_dvdd[] = "dvdd";
+
+static int ak8974_get_u16_val(struct ak8974 *ak8974, u8 reg, u16 *val)
+{
+	int ret;
+	__le16 bulk;
+
+	ret = regmap_bulk_read(ak8974->map, reg, &bulk, 2);
+	if (ret)
+		return ret;
+	*val = le16_to_cpu(bulk);
+
+	return 0;
+}
+
+static int ak8974_set_u16_val(struct ak8974 *ak8974, u8 reg, u16 val)
+{
+	__le16 bulk = cpu_to_le16(val);
+
+	return regmap_bulk_write(ak8974->map, reg, &bulk, 2);
+}
+
+static int ak8974_set_power(struct ak8974 *ak8974, bool mode)
+{
+	int ret;
+	u8 val;
+
+	val = mode ? AK8974_CTRL1_POWER : 0;
+	val |= AK8974_CTRL1_FORCE_EN;
+	ret = regmap_write(ak8974->map, AK8974_CTRL1, val);
+	if (ret < 0)
+		return ret;
+
+	if (mode)
+		msleep(AK8974_ACTIVATE_DELAY);
+
+	return 0;
+}
+
+static int ak8974_reset(struct ak8974 *ak8974)
+{
+	int ret;
+
+	/* Power on to get register access. Sets CTRL1 reg to reset state */
+	ret = ak8974_set_power(ak8974, AK8974_PWR_ON);
+	if (ret)
+		return ret;
+	ret = regmap_write(ak8974->map, AK8974_CTRL2, AK8974_CTRL2_RESDEF);
+	if (ret)
+		return ret;
+	ret = regmap_write(ak8974->map, AK8974_CTRL3, AK8974_CTRL3_RESDEF);
+	if (ret)
+		return ret;
+	ret = regmap_write(ak8974->map, AK8974_INT_CTRL,
+			   AK8974_INT_CTRL_RESDEF);
+	if (ret)
+		return ret;
+
+	/* After reset, power off is default state */
+	return ak8974_set_power(ak8974, AK8974_PWR_OFF);
+}
+
+static int ak8974_configure(struct ak8974 *ak8974)
+{
+	int ret;
+
+	ret = regmap_write(ak8974->map, AK8974_CTRL2, AK8974_CTRL2_DRDY_EN |
+			   AK8974_CTRL2_INT_EN);
+	if (ret)
+		return ret;
+	ret = regmap_write(ak8974->map, AK8974_CTRL3, 0);
+	if (ret)
+		return ret;
+	if (ak8974->variant == AK8974_WHOAMI_VALUE_AMI306) {
+		/* magic from datasheet: set high-speed measurement mode */
+		ret = ak8974_set_u16_val(ak8974, AMI306_CTRL4, 0xA07E);
+		if (ret)
+			return ret;
+	}
+	ret = regmap_write(ak8974->map, AK8974_INT_CTRL, AK8974_INT_CTRL_POL);
+	if (ret)
+		return ret;
+
+	return regmap_write(ak8974->map, AK8974_PRESET, 0);
+}
+
+static int ak8974_trigmeas(struct ak8974 *ak8974)
+{
+	unsigned int clear;
+	u8 mask;
+	u8 val;
+	int ret;
+
+	/* Clear any previous measurement overflow status */
+	ret = regmap_read(ak8974->map, AK8974_INT_CLEAR, &clear);
+	if (ret)
+		return ret;
+
+	/* If we have a DRDY IRQ line, use it */
+	if (ak8974->drdy_irq) {
+		mask = AK8974_CTRL2_INT_EN |
+			AK8974_CTRL2_DRDY_EN |
+			AK8974_CTRL2_DRDY_POL;
+		val = AK8974_CTRL2_DRDY_EN;
+
+		if (!ak8974->drdy_active_low)
+			val |= AK8974_CTRL2_DRDY_POL;
+
+		init_completion(&ak8974->drdy_complete);
+		ret = regmap_update_bits(ak8974->map, AK8974_CTRL2,
+					 mask, val);
+		if (ret)
+			return ret;
+	}
+
+	/* Force a measurement */
+	return regmap_update_bits(ak8974->map,
+				  AK8974_CTRL3,
+				  AK8974_CTRL3_FORCE,
+				  AK8974_CTRL3_FORCE);
+}
+
+static int ak8974_await_drdy(struct ak8974 *ak8974)
+{
+	int timeout = 2;
+	unsigned int val;
+	int ret;
+
+	if (ak8974->drdy_irq) {
+		ret = wait_for_completion_timeout(&ak8974->drdy_complete,
+					1 + msecs_to_jiffies(1000));
+		if (!ret) {
+			dev_err(&ak8974->i2c->dev,
+				"timeout waiting for DRDY IRQ\n");
+			return -ETIMEDOUT;
+		}
+		return 0;
+	}
+
+	/* Default delay-based poll loop */
+	do {
+		msleep(AK8974_MEASTIME);
+		ret = regmap_read(ak8974->map, AK8974_STATUS, &val);
+		if (ret < 0)
+			return ret;
+		if (val & AK8974_STATUS_DRDY)
+			return 0;
+	} while (--timeout);
+
+	dev_err(&ak8974->i2c->dev, "timeout waiting for DRDY\n");
+	return -ETIMEDOUT;
+}
+
+static int ak8974_getresult(struct ak8974 *ak8974, __le16 *result)
+{
+	unsigned int src;
+	int ret;
+
+	ret = ak8974_await_drdy(ak8974);
+	if (ret)
+		return ret;
+	ret = regmap_read(ak8974->map, AK8974_INT_SRC, &src);
+	if (ret < 0)
+		return ret;
+
+	/* Out of range overflow! Strong magnet close? */
+	if (src & AK8974_INT_RANGE) {
+		dev_err(&ak8974->i2c->dev,
+			"range overflow in sensor\n");
+		return -ERANGE;
+	}
+
+	ret = regmap_bulk_read(ak8974->map, AK8974_DATA_X, result, 6);
+	if (ret)
+		return ret;
+
+	return ret;
+}
+
+static irqreturn_t ak8974_drdy_irq(int irq, void *d)
+{
+	struct ak8974 *ak8974 = d;
+
+	if (!ak8974->drdy_irq)
+		return IRQ_NONE;
+
+	/* TODO: timestamp here to get good measurement stamps */
+	return IRQ_WAKE_THREAD;
+}
+
+static irqreturn_t ak8974_drdy_irq_thread(int irq, void *d)
+{
+	struct ak8974 *ak8974 = d;
+	unsigned int val;
+	int ret;
+
+	/* Check if this was a DRDY from us */
+	ret = regmap_read(ak8974->map, AK8974_STATUS, &val);
+	if (ret < 0) {
+		dev_err(&ak8974->i2c->dev, "error reading DRDY status\n");
+		return IRQ_HANDLED;
+	}
+	if (val & AK8974_STATUS_DRDY) {
+		/* Yes this was our IRQ */
+		complete(&ak8974->drdy_complete);
+		return IRQ_HANDLED;
+	}
+
+	/* We may be on a shared IRQ, let the next client check */
+	return IRQ_NONE;
+}
+
+static int ak8974_selftest(struct ak8974 *ak8974)
+{
+	struct device *dev = &ak8974->i2c->dev;
+	unsigned int val;
+	int ret;
+
+	ret = regmap_read(ak8974->map, AK8974_SELFTEST, &val);
+	if (ret)
+		return ret;
+	if (val != AK8974_SELFTEST_IDLE) {
+		dev_err(dev, "selftest not idle before test\n");
+		return -EIO;
+	}
+
+	/* Trigger self-test */
+	ret = regmap_update_bits(ak8974->map,
+			AK8974_CTRL3,
+			AK8974_CTRL3_SELFTEST,
+			AK8974_CTRL3_SELFTEST);
+	if (ret) {
+		dev_err(dev, "could not write CTRL3\n");
+		return ret;
+	}
+
+	msleep(AK8974_SELFTEST_DELAY);
+
+	ret = regmap_read(ak8974->map, AK8974_SELFTEST, &val);
+	if (ret)
+		return ret;
+	if (val != AK8974_SELFTEST_OK) {
+		dev_err(dev, "selftest result NOT OK (%02x)\n", val);
+		return -EIO;
+	}
+
+	ret = regmap_read(ak8974->map, AK8974_SELFTEST, &val);
+	if (ret)
+		return ret;
+	if (val != AK8974_SELFTEST_IDLE) {
+		dev_err(dev, "selftest not idle after test (%02x)\n", val);
+		return -EIO;
+	}
+	dev_dbg(dev, "passed self-test\n");
+
+	return 0;
+}
+
+static void ak8974_read_calib_data(struct ak8974 *ak8974, unsigned int reg,
+				   __le16 *tab, size_t tab_size)
+{
+	int ret = regmap_bulk_read(ak8974->map, reg, tab, tab_size);
+	if (ret) {
+		memset(tab, 0xFF, tab_size);
+		dev_warn(&ak8974->i2c->dev,
+			 "can't read calibration data (regs %u..%zu): %d\n",
+			 reg, reg + tab_size - 1, ret);
+	} else {
+		add_device_randomness(tab, tab_size);
+	}
+}
+
+static int ak8974_detect(struct ak8974 *ak8974)
+{
+	unsigned int whoami;
+	const char *name;
+	int ret;
+	unsigned int fw;
+	u16 sn;
+
+	ret = regmap_read(ak8974->map, AK8974_WHOAMI, &whoami);
+	if (ret)
+		return ret;
+
+	name = "ami305";
+
+	switch (whoami) {
+	case AK8974_WHOAMI_VALUE_AMI306:
+		name = "ami306";
+		/* fall-through */
+	case AK8974_WHOAMI_VALUE_AMI305:
+		ret = regmap_read(ak8974->map, AMI305_VER, &fw);
+		if (ret)
+			return ret;
+		fw &= 0x7f; /* only bits 0 thru 6 valid */
+		ret = ak8974_get_u16_val(ak8974, AMI305_SN, &sn);
+		if (ret)
+			return ret;
+		add_device_randomness(&sn, sizeof(sn));
+		dev_info(&ak8974->i2c->dev,
+			 "detected %s, FW ver %02x, S/N: %04x\n",
+			 name, fw, sn);
+		break;
+	case AK8974_WHOAMI_VALUE_AK8974:
+		name = "ak8974";
+		dev_info(&ak8974->i2c->dev, "detected AK8974\n");
+		break;
+	default:
+		dev_err(&ak8974->i2c->dev, "unsupported device (%02x) ",
+			whoami);
+		return -ENODEV;
+	}
+
+	ak8974->name = name;
+	ak8974->variant = whoami;
+
+	if (whoami == AK8974_WHOAMI_VALUE_AMI306) {
+		__le16 fab_data1[9], fab_data2[3];
+		int i;
+
+		ak8974_read_calib_data(ak8974, AMI306_FINEOUTPUT_X,
+				       fab_data1, sizeof(fab_data1));
+		ak8974_read_calib_data(ak8974, AMI306_OFFZERO_X,
+				       fab_data2, sizeof(fab_data2));
+
+		for (i = 0; i < 3; ++i) {
+			static const char axis[3] = "XYZ";
+			static const char pgaxis[6] = "ZYZXYX";
+			unsigned offz = le16_to_cpu(fab_data2[i]) & 0x7F;
+			unsigned fine = le16_to_cpu(fab_data1[i]);
+			unsigned sens = le16_to_cpu(fab_data1[i + 3]);
+			unsigned pgain1 = le16_to_cpu(fab_data1[i + 6]);
+			unsigned pgain2 = pgain1 >> 8;
+
+			pgain1 &= 0xFF;
+
+			dev_info(&ak8974->i2c->dev,
+				 "factory calibration for axis %c: offz=%u sens=%u fine=%u pga%c=%u pga%c=%u\n",
+				 axis[i], offz, sens, fine, pgaxis[i * 2],
+				 pgain1, pgaxis[i * 2 + 1], pgain2);
+		}
+	}
+
+	return 0;
+}
+
+static int ak8974_read_raw(struct iio_dev *indio_dev,
+			   struct iio_chan_spec const *chan,
+			   int *val, int *val2,
+			   long mask)
+{
+	struct ak8974 *ak8974 = iio_priv(indio_dev);
+	__le16 hw_values[3];
+	int ret = -EINVAL;
+
+	pm_runtime_get_sync(&ak8974->i2c->dev);
+	mutex_lock(&ak8974->lock);
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		if (chan->address > 2) {
+			dev_err(&ak8974->i2c->dev, "faulty channel address\n");
+			ret = -EIO;
+			goto out_unlock;
+		}
+		ret = ak8974_trigmeas(ak8974);
+		if (ret)
+			goto out_unlock;
+		ret = ak8974_getresult(ak8974, hw_values);
+		if (ret)
+			goto out_unlock;
+
+		/*
+		 * We read all axes and discard all but one, for optimized
+		 * reading, use the triggered buffer.
+		 */
+		*val = (s16)le16_to_cpu(hw_values[chan->address]);
+
+		ret = IIO_VAL_INT;
+	}
+
+ out_unlock:
+	mutex_unlock(&ak8974->lock);
+	pm_runtime_mark_last_busy(&ak8974->i2c->dev);
+	pm_runtime_put_autosuspend(&ak8974->i2c->dev);
+
+	return ret;
+}
+
+static void ak8974_fill_buffer(struct iio_dev *indio_dev)
+{
+	struct ak8974 *ak8974 = iio_priv(indio_dev);
+	int ret;
+
+	pm_runtime_get_sync(&ak8974->i2c->dev);
+	mutex_lock(&ak8974->lock);
+
+	ret = ak8974_trigmeas(ak8974);
+	if (ret) {
+		dev_err(&ak8974->i2c->dev, "error triggering measure\n");
+		goto out_unlock;
+	}
+	ret = ak8974_getresult(ak8974, ak8974->scan.channels);
+	if (ret) {
+		dev_err(&ak8974->i2c->dev, "error getting measures\n");
+		goto out_unlock;
+	}
+
+	iio_push_to_buffers_with_timestamp(indio_dev, &ak8974->scan,
+					   iio_get_time_ns(indio_dev));
+
+ out_unlock:
+	mutex_unlock(&ak8974->lock);
+	pm_runtime_mark_last_busy(&ak8974->i2c->dev);
+	pm_runtime_put_autosuspend(&ak8974->i2c->dev);
+}
+
+static irqreturn_t ak8974_handle_trigger(int irq, void *p)
+{
+	const struct iio_poll_func *pf = p;
+	struct iio_dev *indio_dev = pf->indio_dev;
+
+	ak8974_fill_buffer(indio_dev);
+	iio_trigger_notify_done(indio_dev->trig);
+
+	return IRQ_HANDLED;
+}
+
+static const struct iio_mount_matrix *
+ak8974_get_mount_matrix(const struct iio_dev *indio_dev,
+			const struct iio_chan_spec *chan)
+{
+	struct ak8974 *ak8974 = iio_priv(indio_dev);
+
+	return &ak8974->orientation;
+}
+
+static const struct iio_chan_spec_ext_info ak8974_ext_info[] = {
+	IIO_MOUNT_MATRIX(IIO_SHARED_BY_DIR, ak8974_get_mount_matrix),
+	{ },
+};
+
+#define AK8974_AXIS_CHANNEL(axis, index)				\
+	{								\
+		.type = IIO_MAGN,					\
+		.modified = 1,						\
+		.channel2 = IIO_MOD_##axis,				\
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),		\
+		.ext_info = ak8974_ext_info,				\
+		.address = index,					\
+		.scan_index = index,					\
+		.scan_type = {						\
+			.sign = 's',					\
+			.realbits = 16,					\
+			.storagebits = 16,				\
+			.endianness = IIO_LE				\
+		},							\
+	}
+
+static const struct iio_chan_spec ak8974_channels[] = {
+	AK8974_AXIS_CHANNEL(X, 0),
+	AK8974_AXIS_CHANNEL(Y, 1),
+	AK8974_AXIS_CHANNEL(Z, 2),
+	IIO_CHAN_SOFT_TIMESTAMP(3),
+};
+
+static const unsigned long ak8974_scan_masks[] = { 0x7, 0 };
+
+static const struct iio_info ak8974_info = {
+	.read_raw = &ak8974_read_raw,
+};
+
+static bool ak8974_writeable_reg(struct device *dev, unsigned int reg)
+{
+	struct i2c_client *i2c = to_i2c_client(dev);
+	struct iio_dev *indio_dev = i2c_get_clientdata(i2c);
+	struct ak8974 *ak8974 = iio_priv(indio_dev);
+
+	switch (reg) {
+	case AK8974_CTRL1:
+	case AK8974_CTRL2:
+	case AK8974_CTRL3:
+	case AK8974_INT_CTRL:
+	case AK8974_INT_THRES:
+	case AK8974_INT_THRES + 1:
+	case AK8974_PRESET:
+	case AK8974_PRESET + 1:
+		return true;
+	case AK8974_OFFSET_X:
+	case AK8974_OFFSET_X + 1:
+	case AK8974_OFFSET_Y:
+	case AK8974_OFFSET_Y + 1:
+	case AK8974_OFFSET_Z:
+	case AK8974_OFFSET_Z + 1:
+		if (ak8974->variant == AK8974_WHOAMI_VALUE_AK8974)
+			return true;
+		return false;
+	case AMI305_OFFSET_X:
+	case AMI305_OFFSET_X + 1:
+	case AMI305_OFFSET_Y:
+	case AMI305_OFFSET_Y + 1:
+	case AMI305_OFFSET_Z:
+	case AMI305_OFFSET_Z + 1:
+		return ak8974->variant == AK8974_WHOAMI_VALUE_AMI305 ||
+		       ak8974->variant == AK8974_WHOAMI_VALUE_AMI306;
+	case AMI306_CTRL4:
+	case AMI306_CTRL4 + 1:
+		return ak8974->variant == AK8974_WHOAMI_VALUE_AMI306;
+	default:
+		return false;
+	}
+}
+
+static bool ak8974_precious_reg(struct device *dev, unsigned int reg)
+{
+	return reg == AK8974_INT_CLEAR;
+}
+
+static const struct regmap_config ak8974_regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 8,
+	.max_register = 0xff,
+	.writeable_reg = ak8974_writeable_reg,
+	.precious_reg = ak8974_precious_reg,
+};
+
+static int ak8974_probe(struct i2c_client *i2c,
+			const struct i2c_device_id *id)
+{
+	struct iio_dev *indio_dev;
+	struct ak8974 *ak8974;
+	unsigned long irq_trig;
+	int irq = i2c->irq;
+	int ret;
+
+	/* Register with IIO */
+	indio_dev = devm_iio_device_alloc(&i2c->dev, sizeof(*ak8974));
+	if (indio_dev == NULL)
+		return -ENOMEM;
+
+	ak8974 = iio_priv(indio_dev);
+	i2c_set_clientdata(i2c, indio_dev);
+	ak8974->i2c = i2c;
+	mutex_init(&ak8974->lock);
+
+	ret = of_iio_read_mount_matrix(&i2c->dev,
+				       "mount-matrix",
+				       &ak8974->orientation);
+	if (ret)
+		return ret;
+
+	ak8974->regs[0].supply = ak8974_reg_avdd;
+	ak8974->regs[1].supply = ak8974_reg_dvdd;
+
+	ret = devm_regulator_bulk_get(&i2c->dev,
+				      ARRAY_SIZE(ak8974->regs),
+				      ak8974->regs);
+	if (ret < 0) {
+		dev_err(&i2c->dev, "cannot get regulators\n");
+		return ret;
+	}
+
+	ret = regulator_bulk_enable(ARRAY_SIZE(ak8974->regs), ak8974->regs);
+	if (ret < 0) {
+		dev_err(&i2c->dev, "cannot enable regulators\n");
+		return ret;
+	}
+
+	/* Take runtime PM online */
+	pm_runtime_get_noresume(&i2c->dev);
+	pm_runtime_set_active(&i2c->dev);
+	pm_runtime_enable(&i2c->dev);
+
+	ak8974->map = devm_regmap_init_i2c(i2c, &ak8974_regmap_config);
+	if (IS_ERR(ak8974->map)) {
+		dev_err(&i2c->dev, "failed to allocate register map\n");
+		pm_runtime_put_noidle(&i2c->dev);
+		pm_runtime_disable(&i2c->dev);
+		return PTR_ERR(ak8974->map);
+	}
+
+	ret = ak8974_set_power(ak8974, AK8974_PWR_ON);
+	if (ret) {
+		dev_err(&i2c->dev, "could not power on\n");
+		goto disable_pm;
+	}
+
+	ret = ak8974_detect(ak8974);
+	if (ret) {
+		dev_err(&i2c->dev, "neither AK8974 nor AMI30x found\n");
+		goto disable_pm;
+	}
+
+	ret = ak8974_selftest(ak8974);
+	if (ret)
+		dev_err(&i2c->dev, "selftest failed (continuing anyway)\n");
+
+	ret = ak8974_reset(ak8974);
+	if (ret) {
+		dev_err(&i2c->dev, "AK8974 reset failed\n");
+		goto disable_pm;
+	}
+
+	indio_dev->dev.parent = &i2c->dev;
+	indio_dev->channels = ak8974_channels;
+	indio_dev->num_channels = ARRAY_SIZE(ak8974_channels);
+	indio_dev->info = &ak8974_info;
+	indio_dev->available_scan_masks = ak8974_scan_masks;
+	indio_dev->modes = INDIO_DIRECT_MODE;
+	indio_dev->name = ak8974->name;
+
+	ret = iio_triggered_buffer_setup(indio_dev, NULL,
+					 ak8974_handle_trigger,
+					 NULL);
+	if (ret) {
+		dev_err(&i2c->dev, "triggered buffer setup failed\n");
+		goto disable_pm;
+	}
+
+	/* If we have a valid DRDY IRQ, make use of it */
+	if (irq > 0) {
+		irq_trig = irqd_get_trigger_type(irq_get_irq_data(irq));
+		if (irq_trig == IRQF_TRIGGER_RISING) {
+			dev_info(&i2c->dev, "enable rising edge DRDY IRQ\n");
+		} else if (irq_trig == IRQF_TRIGGER_FALLING) {
+			ak8974->drdy_active_low = true;
+			dev_info(&i2c->dev, "enable falling edge DRDY IRQ\n");
+		} else {
+			irq_trig = IRQF_TRIGGER_RISING;
+		}
+		irq_trig |= IRQF_ONESHOT;
+		irq_trig |= IRQF_SHARED;
+
+		ret = devm_request_threaded_irq(&i2c->dev,
+						irq,
+						ak8974_drdy_irq,
+						ak8974_drdy_irq_thread,
+						irq_trig,
+						ak8974->name,
+						ak8974);
+		if (ret) {
+			dev_err(&i2c->dev, "unable to request DRDY IRQ "
+				"- proceeding without IRQ\n");
+			goto no_irq;
+		}
+		ak8974->drdy_irq = true;
+	}
+
+no_irq:
+	ret = iio_device_register(indio_dev);
+	if (ret) {
+		dev_err(&i2c->dev, "device register failed\n");
+		goto cleanup_buffer;
+	}
+
+	pm_runtime_set_autosuspend_delay(&i2c->dev,
+					 AK8974_AUTOSUSPEND_DELAY);
+	pm_runtime_use_autosuspend(&i2c->dev);
+	pm_runtime_put(&i2c->dev);
+
+	return 0;
+
+cleanup_buffer:
+	iio_triggered_buffer_cleanup(indio_dev);
+disable_pm:
+	pm_runtime_put_noidle(&i2c->dev);
+	pm_runtime_disable(&i2c->dev);
+	ak8974_set_power(ak8974, AK8974_PWR_OFF);
+	regulator_bulk_disable(ARRAY_SIZE(ak8974->regs), ak8974->regs);
+
+	return ret;
+}
+
+static int ak8974_remove(struct i2c_client *i2c)
+{
+	struct iio_dev *indio_dev = i2c_get_clientdata(i2c);
+	struct ak8974 *ak8974 = iio_priv(indio_dev);
+
+	iio_device_unregister(indio_dev);
+	iio_triggered_buffer_cleanup(indio_dev);
+	pm_runtime_get_sync(&i2c->dev);
+	pm_runtime_put_noidle(&i2c->dev);
+	pm_runtime_disable(&i2c->dev);
+	ak8974_set_power(ak8974, AK8974_PWR_OFF);
+	regulator_bulk_disable(ARRAY_SIZE(ak8974->regs), ak8974->regs);
+
+	return 0;
+}
+
+static int __maybe_unused ak8974_runtime_suspend(struct device *dev)
+{
+	struct ak8974 *ak8974 =
+		iio_priv(i2c_get_clientdata(to_i2c_client(dev)));
+
+	ak8974_set_power(ak8974, AK8974_PWR_OFF);
+	regulator_bulk_disable(ARRAY_SIZE(ak8974->regs), ak8974->regs);
+
+	return 0;
+}
+
+static int __maybe_unused ak8974_runtime_resume(struct device *dev)
+{
+	struct ak8974 *ak8974 =
+		iio_priv(i2c_get_clientdata(to_i2c_client(dev)));
+	int ret;
+
+	ret = regulator_bulk_enable(ARRAY_SIZE(ak8974->regs), ak8974->regs);
+	if (ret)
+		return ret;
+	msleep(AK8974_POWERON_DELAY);
+	ret = ak8974_set_power(ak8974, AK8974_PWR_ON);
+	if (ret)
+		goto out_regulator_disable;
+
+	ret = ak8974_configure(ak8974);
+	if (ret)
+		goto out_disable_power;
+
+	return 0;
+
+out_disable_power:
+	ak8974_set_power(ak8974, AK8974_PWR_OFF);
+out_regulator_disable:
+	regulator_bulk_disable(ARRAY_SIZE(ak8974->regs), ak8974->regs);
+
+	return ret;
+}
+
+static const struct dev_pm_ops ak8974_dev_pm_ops = {
+	SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
+				pm_runtime_force_resume)
+	SET_RUNTIME_PM_OPS(ak8974_runtime_suspend,
+			   ak8974_runtime_resume, NULL)
+};
+
+static const struct i2c_device_id ak8974_id[] = {
+	{"ami305", 0 },
+	{"ami306", 0 },
+	{"ak8974", 0 },
+	{}
+};
+MODULE_DEVICE_TABLE(i2c, ak8974_id);
+
+static const struct of_device_id ak8974_of_match[] = {
+	{ .compatible = "asahi-kasei,ak8974", },
+	{}
+};
+MODULE_DEVICE_TABLE(of, ak8974_of_match);
+
+static struct i2c_driver ak8974_driver = {
+	.driver	 = {
+		.name	= "ak8974",
+		.pm = &ak8974_dev_pm_ops,
+		.of_match_table = of_match_ptr(ak8974_of_match),
+	},
+	.probe	  = ak8974_probe,
+	.remove	  = ak8974_remove,
+	.id_table = ak8974_id,
+};
+module_i2c_driver(ak8974_driver);
+
+MODULE_DESCRIPTION("AK8974 and AMI30x 3-axis magnetometer driver");
+MODULE_AUTHOR("Samu Onkalo");
+MODULE_AUTHOR("Linus Walleij");
+MODULE_LICENSE("GPL v2");