[v2,3/4] iio: magnetometer: add a driver for Voltafield AF8133J magnetometer

Message ID 20240212175410.3101973-4-megi@xff.cz
State New
Headers
Series Add support for AF8133J magnetometer |

Commit Message

Ondřej Jirman Feb. 12, 2024, 5:53 p.m. UTC
  From: Icenowy Zheng <icenowy@aosc.io>

AF8133J is a simple I2C-connected magnetometer, without interrupts.

Add a simple IIO driver for it.

Co-developed-by: Icenowy Zheng <icenowy@aosc.io>
Signed-off-by: Icenowy Zheng <icenowy@aosc.io>
Signed-off-by: Dalton Durst <dalton@ubports.com>
Signed-off-by: Shoji Keita <awaittrot@shjk.jp>
Co-developed-by: Ondrej Jirman <megi@xff.cz>
Signed-off-by: Ondrej Jirman <megi@xff.cz>
---
 drivers/iio/magnetometer/Kconfig   |  12 +
 drivers/iio/magnetometer/Makefile  |   1 +
 drivers/iio/magnetometer/af8133j.c | 528 +++++++++++++++++++++++++++++
 3 files changed, 541 insertions(+)
 create mode 100644 drivers/iio/magnetometer/af8133j.c
  

Comments

Andrey Skvortsov Feb. 13, 2024, 9:21 p.m. UTC | #1
Hi Ondřej,

thank you for submitting the driver.

On 24-02-12 18:53, Ondřej Jirman wrote:
> From: Icenowy Zheng <icenowy@aosc.io>
> 
> AF8133J is a simple I2C-connected magnetometer, without interrupts.
> 
> Add a simple IIO driver for it.
> 
> Co-developed-by: Icenowy Zheng <icenowy@aosc.io>
> Signed-off-by: Icenowy Zheng <icenowy@aosc.io>
> Signed-off-by: Dalton Durst <dalton@ubports.com>
> Signed-off-by: Shoji Keita <awaittrot@shjk.jp>
> Co-developed-by: Ondrej Jirman <megi@xff.cz>
> Signed-off-by: Ondrej Jirman <megi@xff.cz>
> ---
>  drivers/iio/magnetometer/Kconfig   |  12 +
>  drivers/iio/magnetometer/Makefile  |   1 +
>  drivers/iio/magnetometer/af8133j.c | 528 +++++++++++++++++++++++++++++
>  3 files changed, 541 insertions(+)
>  create mode 100644 drivers/iio/magnetometer/af8133j.c
> 
> diff --git a/drivers/iio/magnetometer/Kconfig b/drivers/iio/magnetometer/Kconfig
> index 38532d840f2a..cd2917d71904 100644
> --- a/drivers/iio/magnetometer/Kconfig
> +++ b/drivers/iio/magnetometer/Kconfig
> @@ -6,6 +6,18 @@
>  

Reviewed-by: Andrey Skvortsov <andrej.skvortzov@gmail.com>

I've successfully tested driver from v2 on 6.8-rc3.
  
Jonathan Cameron Feb. 16, 2024, 3:39 p.m. UTC | #2
On Wed, 14 Feb 2024 18:43:10 +0100
Ondřej Jirman <megi@xff.cz> wrote:

> Hi Jonathan,

Gah. Runtime pm always gives me a headache. I'd indeed misunderstood some
of what you are doing.
> 
> On Wed, Feb 14, 2024 at 05:01:36PM +0000, Jonathan Cameron wrote:
> > On Mon, 12 Feb 2024 18:53:55 +0100
> > Ondřej Jirman <megi@xff.cz> wrote:
> >   
> > > From: Icenowy Zheng <icenowy@aosc.io>
> > > 
> > > AF8133J is a simple I2C-connected magnetometer, without interrupts.
> > > 
> > > Add a simple IIO driver for it.
> > > 
> > > Co-developed-by: Icenowy Zheng <icenowy@aosc.io>
> > > Signed-off-by: Icenowy Zheng <icenowy@aosc.io>
> > > Signed-off-by: Dalton Durst <dalton@ubports.com>
> > > Signed-off-by: Shoji Keita <awaittrot@shjk.jp>
> > > Co-developed-by: Ondrej Jirman <megi@xff.cz>
> > > Signed-off-by: Ondrej Jirman <megi@xff.cz>  
> > 
> > 
> > Hi a few comments (mostly on changes)
> > 
> > The runtime_pm handling can be simplified somewhat if you
> > rearrange probe a little.
> >   
> > > diff --git a/drivers/iio/magnetometer/af8133j.c b/drivers/iio/magnetometer/af8133j.c
> > > new file mode 100644
> > > index 000000000000..1f64a2337f6e
> > > --- /dev/null
> > > +++ b/drivers/iio/magnetometer/af8133j.c
> > > @@ -0,0 +1,528 @@  
> > 
> >   
> > > +static int af8133j_take_measurement(struct af8133j_data *data)
> > > +{
> > > +	unsigned int val;
> > > +	int ret;
> > > +
> > > +	ret = regmap_write(data->regmap,
> > > +			   AF8133J_REG_STATE, AF8133J_REG_STATE_WORK);
> > > +	if (ret < 0)
> > > +		return ret;
> > > +
> > > +	/* The datasheet says "Mesaure Time <1.5ms" */
> > > +	ret = regmap_read_poll_timeout(data->regmap, AF8133J_REG_STATUS, val,
> > > +				       val & AF8133J_REG_STATUS_ACQ,
> > > +				       500, 1500);
> > > +	if (ret < 0)
> > > +		return ret;
> > > +
> > > +	ret = regmap_write(data->regmap,
> > > +			   AF8133J_REG_STATE, AF8133J_REG_STATE_STBY);  
> > 
> > return regmap_write()
> > 
> > regmap accesses return 0 or a negative error code enabling little code
> > reductions like this.  
> 
> Yeah, some reviewers dislike this, because modifying the code in the future
> creates a more unpleasant diff. But if you like this style, I don't mind
> changing it.

Always a gamble on chance of a modification coming.

In general I'd check regmap calls with if (ret) but don't feel that strongly
about that either.

So not really important either way.
> 
> > > +	if (ret < 0)
> > > +		return ret;
> > > +
> > > +	return 0;
> > > +}
> > > +
> > > +static int af8133j_read_measurement(struct af8133j_data *data, __le16 buf[3])
> > > +{
> > > +	struct device *dev = &data->client->dev;
> > > +	int ret;
> > > +
> > > +	ret = pm_runtime_resume_and_get(dev);
> > > +	if (ret) {
> > > +		/*
> > > +		 * Ignore EACCES because that happens when RPM is disabled
> > > +		 * during system sleep, while userspace leave eg. hrtimer
> > > +		 * trigger attached and IIO core keeps trying to do measurements.  
> > 
> > Yeah. We still need to fix that more elegantly :(
> >   
> > > +		 */
> > > +		if (ret != -EACCES)
> > > +			dev_err(dev, "Failed to power on (%d)\n", ret);
> > > +		return ret;
> > > +	}
> > > +
> > > +	scoped_guard(mutex, &data->mutex) {
> > > +		ret = af8133j_take_measurement(data);
> > > +		if (ret)
> > > +			goto out_rpm_put;
> > > +
> > > +		ret = regmap_bulk_read(data->regmap, AF8133J_REG_OUT,
> > > +				       buf, sizeof(__le16) * 3);
> > > +	}
> > > +
> > > +out_rpm_put:
> > > +	pm_runtime_mark_last_busy(dev);
> > > +	pm_runtime_put_autosuspend(dev);
> > > +
> > > +	return ret;
> > > +}
> > > +  
> > 
> >   
> > > +
> > > +static int af8133j_set_scale(struct af8133j_data *data,
> > > +			     unsigned int val, unsigned int val2)
> > > +{
> > > +	struct device *dev = &data->client->dev;
> > > +	u8 range;
> > > +	int ret = 0;
> > > +
> > > +	if (af8133j_scales[0][0] == val && af8133j_scales[0][1] == val2)
> > > +		range = AF8133J_REG_RANGE_12G;
> > > +	else if (af8133j_scales[1][0] == val && af8133j_scales[1][1] == val2)
> > > +		range = AF8133J_REG_RANGE_22G;
> > > +	else
> > > +		return -EINVAL;
> > > +
> > > +	pm_runtime_disable(dev);
> > > +
> > > +	/*
> > > +	 * When suspended, just store the new range to data->range to be
> > > +	 * applied later during power up.  
> > Better to just do
> > 	pm_runtime_resume_and_get() here
> >   
> > > +	 */
> > > +	if (!pm_runtime_status_suspended(dev))
> > > +		ret = regmap_write(data->regmap, AF8133J_REG_RANGE, range);
> > > +
> > > +	pm_runtime_enable(dev);  
> > and
> > 	pm_runtime_mark_last_busy(dev);
> > 	pm_runtime_put_autosuspend(dev);
> > here.
> > 
> > The userspace interface is only way this function is called so rearrange
> > probe a little so that you don't need extra complexity in these functions.  
> 
> It doesn't make sense to wakeup the device for range change, because it will
> forget the range the moment it's powered off again, after changing the range.

Ah.  I'd missed understood that. Thanks for extra explanation.

I'm not keen on the enable / disable dance but anything else is probably worse
(delaying update until we actually using it etc).



> 
> Also this function has nothing to do with probe. data->range is authoritative
> value, not cache. It gets applied to HW on each power up.
> 
> >   
> > > +
> > > +	data->range = range;  
> > 
> > If the write failed, generally don't update the cached value.  
> 
> Right.
> 
> > > +	return ret;
> > > +}
> > > +
> > > +static int af8133j_write_raw(struct iio_dev *indio_dev,
> > > +			     struct iio_chan_spec const *chan,
> > > +			     int val, int val2, long mask)
> > > +{
> > > +	struct af8133j_data *data = iio_priv(indio_dev);
> > > +	int ret;
> > > +
> > > +	switch (mask) {
> > > +	case IIO_CHAN_INFO_SCALE:
> > > +		scoped_guard(mutex, &data->mutex)
> > > +			ret = af8133j_set_scale(data, val, val2);  
> > 
> > Look more closely at what scoped_guard() does.
> > 			return af8133j_set_scale(data, val, val2);
> > is fine and simpler as no local variable needed.  
> 
> I did, it will not work as you suggest. It's implemented as for loop with
> condition, and the compiler will complain about fallthrough.
> 
> I can do:
> 
> 		scoped_guard(mutex, &data->mutex)
> 			return af8133j_set_scale(data, val, val2);
> 		return 0;
> 
> but it looks weirder at first glance, at least to my eye.

I agree that bit is less than ideal, but with your code it should also
get confused about whether ret is ever set.

		scoped_guard(mutex, &data->mutex)
			return ...
		unreachable();

perhaps?  or just use a guard and add scope manually

	case IIO_CHAN_INFO_SCALE: {
		guard(mutex)(&data->mutex);

		return af8133j_set_scale(...);
	}

I'd go with this as the cleanest solution in this case.


> 
> > > +		return ret;
> > > +	default:
> > > +		return -EINVAL;
> > > +	}
> > > +}  
> >   
> > > +static void af8133j_power_down_action(void *ptr)
> > > +{
> > > +	struct af8133j_data *data = ptr;
> > > +	struct device *dev = &data->client->dev;
> > > +
> > > +	pm_runtime_disable(dev);  
> > You group together unwinding of calls that occur in very
> > different places in probe.  Don't do that as it leas
> > to disabling runtime pm having never enabled it
> > in some error paths.  That may be safe but if fails the
> > obviously correct test.  
> 
> This whole disable/enable dance is here so that pm_runtime_status_suspended can
> be trusted. Not for disabling PM during device remove or in error paths.
> 
> There's no imbalance here or problem with disabling PM when it's already
> disabled. Disable/enable is reference counted, and this function keeps the
> balance.

Whilst not buggy but I still want to be able to cleanly associate a given
bit of cleanup with what is being cleaned up.  That is the path to
maintainable code longer term.  Runtime PM does make a mess of doing this
but tends to have somewhat logical sets of calls that go together.

As long as we hold a reference, doesn't matter when we turn it on in probe()
Only the put_autosuspend has to come after we done talking to it.




	
> 
> > So this is a good solution to the normal dance of turning power on
> > just to turn it off shortly afterwards.
> >   
> > > +		af8133j_power_down(data);
> > > +	pm_runtime_enable(dev);  
> > Why?  
> 
> See above. To keep the disable ref count balanced.
> 
> Looks like actual RPM disable already happened at this point a bit earlier in
> another callback registered via devm_pm_runtime_enable(). I guess this
> pm_runtime_enable()/pm_runtime_disable() guard can just be skipped, because RPM
> is already disabled thanks to reverse ordering of devm callbacks during device
> remove. So while this is safe, it's redundant at this point and call to 
> pm_runtime_status_suspended() is safe without this.

Yes, That's a side effect of only enabling it right at the end.

> 
> > > +}
> > > +
> > > +static int af8133j_probe(struct i2c_client *client)
> > > +{
> > > +	struct device *dev = &client->dev;
> > > +	struct af8133j_data *data;
> > > +	struct iio_dev *indio_dev;
> > > +	struct regmap *regmap;
> > > +	int ret, i;
> > > +
> > > +	indio_dev = devm_iio_device_alloc(dev, sizeof(*data));
> > > +	if (!indio_dev)
> > > +		return -ENOMEM;
> > > +
> > > +	regmap = devm_regmap_init_i2c(client, &af8133j_regmap_config);
> > > +	if (IS_ERR(regmap))
> > > +		return dev_err_probe(dev, PTR_ERR(regmap),
> > > +				     "regmap initialization failed\n");
> > > +
> > > +	data = iio_priv(indio_dev);
> > > +	i2c_set_clientdata(client, indio_dev);
> > > +	data->client = client;
> > > +	data->regmap = regmap;
> > > +	data->range = AF8133J_REG_RANGE_12G;
> > > +	mutex_init(&data->mutex);
> > > +
> > > +	data->reset_gpiod = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH);
> > > +	if (IS_ERR(data->reset_gpiod))
> > > +		return dev_err_probe(dev, PTR_ERR(data->reset_gpiod),
> > > +				     "Failed to get reset gpio\n");
> > > +
> > > +	for (i = 0; i < ARRAY_SIZE(af8133j_supply_names); i++)
> > > +		data->supplies[i].supply = af8133j_supply_names[i];
> > > +	ret = devm_regulator_bulk_get(dev, ARRAY_SIZE(data->supplies),
> > > +				      data->supplies);
> > > +	if (ret)
> > > +		return ret;
> > > +
> > > +	ret = iio_read_mount_matrix(dev, &data->orientation);
> > > +	if (ret)
> > > +		return dev_err_probe(dev, ret, "Failed to read mount matrix\n");
> > > +
> > > +	ret = af8133j_power_up(data);
> > > +	if (ret)
> > > +		return ret;
> > > +
> > > +	pm_runtime_set_active(dev);
> > > +
> > > +	ret = devm_add_action_or_reset(dev, af8133j_power_down_action, data);  
> > 
> > As mentioned above, this should only undo things done before this point.
> > So just the af8133j_power_down() I think.  
> 
> The callback doesn't do anything else but power down. It leaves everything
> else as is after it exits.
> 
> > > +	if (ret)
> > > +		return ret;
> > > +
> > > +	ret = af8133j_product_check(data);
> > > +	if (ret)
> > > +		return ret;
> > > +
> > > +	indio_dev->info = &af8133j_info;
> > > +	indio_dev->name = "af8133j";
> > > +	indio_dev->channels = af8133j_channels;
> > > +	indio_dev->num_channels = ARRAY_SIZE(af8133j_channels);
> > > +	indio_dev->modes = INDIO_DIRECT_MODE;
> > > +
> > > +	ret = devm_iio_triggered_buffer_setup(dev, indio_dev, NULL,
> > > +					      &af8133j_trigger_handler, NULL);
> > > +	if (ret < 0)
> > > +		return dev_err_probe(&client->dev, ret,
> > > +				     "Failed to setup iio triggered buffer\n");
> > > +
> > > +	ret = devm_iio_device_register(dev, indio_dev);
> > > +	if (ret)
> > > +		return dev_err_probe(dev, ret, "Failed to register iio device");
> > > +
> > > +	pm_runtime_get_noresume(dev);  
> >   
> > > +	pm_runtime_use_autosuspend(dev);
> > > +	pm_runtime_set_autosuspend_delay(dev, 500);
> > > +	ret = devm_pm_runtime_enable(dev);  
> > 
> > This already deals with pm_runtime_disable() so you shouldn't need do it manually.  
> 
> I'm not disabling RPM manually, it was just used as temporary guard to be able
> to read pm_runtime_status_suspended() safely.

I'd indeed misunderstood that. I forgot the oddity that runtime pm is effectively
reference counting in only one direction for enable / disable and the opposite
one for get and put.

pm_runtime_disable()
pm_runtime_disable()
pm_runtime_enable()
pm_runtime_enable()
pm_runtime_enable()
is fine, but

pm_runtime_enable()
pm_runtime_enable()
pm_runtime_disable()
pm_runtime_disable()
pm_runtime_enable()
is not.

Which makes sense when you realise it's all about ensuring it is off, but
never ensuring that it is turned on.




> 
> > Also you want to enable that before the devm_iio_device_register() to avoid
> > problems with it not being available as the userspace interfaces are used.
> >
> > So just move this up a few lines.  
> 
> Good idea, thanks.
> 
> kind regards,
> 	o.
> 
> > 
> >   
> > > +	if (ret)
> > > +		return ret;
> > > +
> > > +	pm_runtime_put_autosuspend(dev);
> > > +
> > > +	return 0;
> > > +}  
> >
  

Patch

diff --git a/drivers/iio/magnetometer/Kconfig b/drivers/iio/magnetometer/Kconfig
index 38532d840f2a..cd2917d71904 100644
--- a/drivers/iio/magnetometer/Kconfig
+++ b/drivers/iio/magnetometer/Kconfig
@@ -6,6 +6,18 @@ 
 
 menu "Magnetometer sensors"
 
+config AF8133J
+	tristate "Voltafield AF8133J 3-Axis Magnetometer"
+	depends on I2C
+	depends on OF
+	select REGMAP_I2C
+	help
+	  Say yes here to build support for Voltafield AF8133J I2C-based
+	  3-axis magnetometer chip.
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called af8133j.
+
 config AK8974
 	tristate "Asahi Kasei AK8974 3-Axis Magnetometer"
 	depends on I2C
diff --git a/drivers/iio/magnetometer/Makefile b/drivers/iio/magnetometer/Makefile
index b1c784ea71c8..ec5c46fbf999 100644
--- a/drivers/iio/magnetometer/Makefile
+++ b/drivers/iio/magnetometer/Makefile
@@ -4,6 +4,7 @@ 
 #
 
 # When adding new entries keep the list in alphabetical order
+obj-$(CONFIG_AF8133J)	+= af8133j.o
 obj-$(CONFIG_AK8974)	+= ak8974.o
 obj-$(CONFIG_AK8975)	+= ak8975.o
 obj-$(CONFIG_BMC150_MAGN) += bmc150_magn.o
diff --git a/drivers/iio/magnetometer/af8133j.c b/drivers/iio/magnetometer/af8133j.c
new file mode 100644
index 000000000000..1f64a2337f6e
--- /dev/null
+++ b/drivers/iio/magnetometer/af8133j.c
@@ -0,0 +1,528 @@ 
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * af8133j.c - Voltafield AF8133J magnetometer driver
+ *
+ * Copyright 2021 Icenowy Zheng <icenowy@aosc.io>
+ * Copyright 2024 Ondřej Jirman <megi@xff.cz>
+ */
+
+#include <linux/delay.h>
+#include <linux/gpio/consumer.h>
+#include <linux/i2c.h>
+#include <linux/module.h>
+#include <linux/pm_runtime.h>
+#include <linux/regmap.h>
+#include <linux/regulator/consumer.h>
+
+#include <linux/iio/iio.h>
+#include <linux/iio/trigger_consumer.h>
+#include <linux/iio/triggered_buffer.h>
+
+#define AF8133J_REG_OUT		0x03
+#define AF8133J_REG_PCODE	0x00
+#define AF8133J_REG_PCODE_VAL	0x5e
+#define AF8133J_REG_STATUS	0x02
+#define AF8133J_REG_STATUS_ACQ	BIT(0)
+#define AF8133J_REG_STATE	0x0a
+#define AF8133J_REG_STATE_STBY	0x00
+#define AF8133J_REG_STATE_WORK	0x01
+#define AF8133J_REG_RANGE	0x0b
+#define AF8133J_REG_RANGE_22G	0x12
+#define AF8133J_REG_RANGE_12G	0x34
+#define AF8133J_REG_SWR		0x11
+#define AF8133J_REG_SWR_PERFORM	0x81
+
+static const char * const af8133j_supply_names[] = {
+	"avdd",
+	"dvdd",
+};
+
+struct af8133j_data {
+	struct i2c_client *client;
+	struct regmap *regmap;
+	struct mutex mutex;
+	struct iio_mount_matrix orientation;
+
+	struct gpio_desc *reset_gpiod;
+	struct regulator_bulk_data supplies[ARRAY_SIZE(af8133j_supply_names)];
+
+	u8 range;
+};
+
+enum af8133j_axis {
+	AXIS_X = 0,
+	AXIS_Y,
+	AXIS_Z,
+};
+
+static struct iio_mount_matrix *
+af8133j_get_mount_matrix(struct iio_dev *indio_dev,
+			 const struct iio_chan_spec *chan)
+{
+	struct af8133j_data *data = iio_priv(indio_dev);
+
+	return &data->orientation;
+}
+
+static const struct iio_chan_spec_ext_info af8133j_ext_info[] = {
+	IIO_MOUNT_MATRIX(IIO_SHARED_BY_DIR, af8133j_get_mount_matrix),
+	{ }
+};
+
+#define AF8133J_CHANNEL(_si, _axis) { \
+	.type = IIO_MAGN, \
+	.modified = 1, \
+	.channel2 = IIO_MOD_ ## _axis, \
+	.address = AXIS_ ## _axis, \
+	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
+	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
+	.info_mask_shared_by_type_available = BIT(IIO_CHAN_INFO_SCALE), \
+	.ext_info = af8133j_ext_info, \
+	.scan_index = _si, \
+	.scan_type = { \
+		.sign = 's', \
+		.realbits = 16, \
+		.storagebits = 16, \
+		.endianness = IIO_LE, \
+	}, \
+}
+
+static const struct iio_chan_spec af8133j_channels[] = {
+	AF8133J_CHANNEL(0, X),
+	AF8133J_CHANNEL(1, Y),
+	AF8133J_CHANNEL(2, Z),
+	IIO_CHAN_SOFT_TIMESTAMP(3),
+};
+
+static int af8133j_product_check(struct af8133j_data *data)
+{
+	struct device *dev = &data->client->dev;
+	unsigned int val;
+	int ret;
+
+	ret = regmap_read(data->regmap, AF8133J_REG_PCODE, &val);
+	if (ret < 0) {
+		dev_err(dev, "Error reading product code (%d)\n", ret);
+		return ret;
+	}
+
+	if (val != AF8133J_REG_PCODE_VAL) {
+		dev_err(dev, "Invalid product code (0x%02x)\n", val);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int af8133j_reset(struct af8133j_data *data)
+{
+	struct device *dev = &data->client->dev;
+	int ret;
+
+	if (data->reset_gpiod) {
+		/* If we have GPIO reset line, use it */
+		gpiod_set_value_cansleep(data->reset_gpiod, 1);
+		udelay(10);
+		gpiod_set_value_cansleep(data->reset_gpiod, 0);
+	} else {
+		/* Otherwise use software reset */
+		ret = regmap_write(data->regmap, AF8133J_REG_SWR,
+				   AF8133J_REG_SWR_PERFORM);
+		if (ret < 0) {
+			dev_err(dev, "Failed to reset the chip\n");
+			return ret;
+		}
+	}
+
+	/* Wait for reset to finish */
+	usleep_range(1000, 1100);
+
+	/* Restore range setting */
+	if (data->range == AF8133J_REG_RANGE_22G) {
+		ret = regmap_write(data->regmap, AF8133J_REG_RANGE, data->range);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+static void af8133j_power_down(struct af8133j_data *data)
+{
+	gpiod_set_value_cansleep(data->reset_gpiod, 1);
+	regulator_bulk_disable(ARRAY_SIZE(data->supplies), data->supplies);
+}
+
+static int af8133j_power_up(struct af8133j_data *data)
+{
+	struct device *dev = &data->client->dev;
+	int ret;
+
+	ret = regulator_bulk_enable(ARRAY_SIZE(data->supplies), data->supplies);
+	if (ret) {
+		dev_err(dev, "Could not enable regulators\n");
+		return ret;
+	}
+
+	gpiod_set_value_cansleep(data->reset_gpiod, 0);
+
+	/* Wait for power on reset */
+	usleep_range(15000, 16000);
+
+	ret = af8133j_reset(data);
+	if (ret) {
+		af8133j_power_down(data);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int af8133j_take_measurement(struct af8133j_data *data)
+{
+	unsigned int val;
+	int ret;
+
+	ret = regmap_write(data->regmap,
+			   AF8133J_REG_STATE, AF8133J_REG_STATE_WORK);
+	if (ret < 0)
+		return ret;
+
+	/* The datasheet says "Mesaure Time <1.5ms" */
+	ret = regmap_read_poll_timeout(data->regmap, AF8133J_REG_STATUS, val,
+				       val & AF8133J_REG_STATUS_ACQ,
+				       500, 1500);
+	if (ret < 0)
+		return ret;
+
+	ret = regmap_write(data->regmap,
+			   AF8133J_REG_STATE, AF8133J_REG_STATE_STBY);
+	if (ret < 0)
+		return ret;
+
+	return 0;
+}
+
+static int af8133j_read_measurement(struct af8133j_data *data, __le16 buf[3])
+{
+	struct device *dev = &data->client->dev;
+	int ret;
+
+	ret = pm_runtime_resume_and_get(dev);
+	if (ret) {
+		/*
+		 * Ignore EACCES because that happens when RPM is disabled
+		 * during system sleep, while userspace leave eg. hrtimer
+		 * trigger attached and IIO core keeps trying to do measurements.
+		 */
+		if (ret != -EACCES)
+			dev_err(dev, "Failed to power on (%d)\n", ret);
+		return ret;
+	}
+
+	scoped_guard(mutex, &data->mutex) {
+		ret = af8133j_take_measurement(data);
+		if (ret)
+			goto out_rpm_put;
+
+		ret = regmap_bulk_read(data->regmap, AF8133J_REG_OUT,
+				       buf, sizeof(__le16) * 3);
+	}
+
+out_rpm_put:
+	pm_runtime_mark_last_busy(dev);
+	pm_runtime_put_autosuspend(dev);
+
+	return ret;
+}
+
+static const int af8133j_scales[][2] = {
+	[0] = { 0, 366210 }, // 12 gauss
+	[1] = { 0, 671386 }, // 22 gauss
+};
+
+static int af8133j_read_raw(struct iio_dev *indio_dev,
+			    struct iio_chan_spec const *chan, int *val,
+			    int *val2, long mask)
+{
+	struct af8133j_data *data = iio_priv(indio_dev);
+	__le16 buf[3];
+	int ret;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		ret = af8133j_read_measurement(data, buf);
+		if (ret < 0)
+			return ret;
+
+		*val = sign_extend32(le16_to_cpu(buf[chan->address]),
+				     chan->scan_type.realbits - 1);
+		return IIO_VAL_INT;
+	case IIO_CHAN_INFO_SCALE:
+		*val = 0;
+
+		if (data->range == AF8133J_REG_RANGE_12G)
+			*val2 = af8133j_scales[0][1];
+		else
+			*val2 = af8133j_scales[1][1];
+
+		return IIO_VAL_INT_PLUS_NANO;
+	default:
+		return -EINVAL;
+	}
+}
+
+static int af8133j_read_avail(struct iio_dev *indio_dev,
+			      struct iio_chan_spec const *chan,
+			      const int **vals, int *type, int *length,
+			      long mask)
+{
+	switch (mask) {
+	case IIO_CHAN_INFO_SCALE:
+		*vals = (const int *)af8133j_scales;
+		*length = ARRAY_SIZE(af8133j_scales) * 2;
+		*type = IIO_VAL_INT_PLUS_NANO;
+		return IIO_AVAIL_LIST;
+	default:
+		return -EINVAL;
+	}
+}
+
+static int af8133j_set_scale(struct af8133j_data *data,
+			     unsigned int val, unsigned int val2)
+{
+	struct device *dev = &data->client->dev;
+	u8 range;
+	int ret = 0;
+
+	if (af8133j_scales[0][0] == val && af8133j_scales[0][1] == val2)
+		range = AF8133J_REG_RANGE_12G;
+	else if (af8133j_scales[1][0] == val && af8133j_scales[1][1] == val2)
+		range = AF8133J_REG_RANGE_22G;
+	else
+		return -EINVAL;
+
+	pm_runtime_disable(dev);
+
+	/*
+	 * When suspended, just store the new range to data->range to be
+	 * applied later during power up.
+	 */
+	if (!pm_runtime_status_suspended(dev))
+		ret = regmap_write(data->regmap, AF8133J_REG_RANGE, range);
+
+	pm_runtime_enable(dev);
+
+	data->range = range;
+	return ret;
+}
+
+static int af8133j_write_raw(struct iio_dev *indio_dev,
+			     struct iio_chan_spec const *chan,
+			     int val, int val2, long mask)
+{
+	struct af8133j_data *data = iio_priv(indio_dev);
+	int ret;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_SCALE:
+		scoped_guard(mutex, &data->mutex)
+			ret = af8133j_set_scale(data, val, val2);
+		return ret;
+	default:
+		return -EINVAL;
+	}
+}
+
+static int af8133j_write_raw_get_fmt(struct iio_dev *indio_dev,
+				     struct iio_chan_spec const *chan,
+				     long mask)
+{
+	return IIO_VAL_INT_PLUS_NANO;
+}
+
+static const struct iio_info af8133j_info = {
+	.read_raw = af8133j_read_raw,
+	.read_avail = af8133j_read_avail,
+	.write_raw = af8133j_write_raw,
+	.write_raw_get_fmt = af8133j_write_raw_get_fmt,
+};
+
+static irqreturn_t af8133j_trigger_handler(int irq, void *p)
+{
+	struct iio_poll_func *pf = p;
+	struct iio_dev *indio_dev = pf->indio_dev;
+	struct af8133j_data *data = iio_priv(indio_dev);
+	s64 timestamp = iio_get_time_ns(indio_dev);
+	struct {
+		__le16 values[3];
+		s64 timestamp __aligned(8);
+	} sample;
+	int ret;
+
+	memset(&sample, 0, sizeof(sample));
+
+	ret = af8133j_read_measurement(data, sample.values);
+	if (ret)
+		goto out_done;
+
+	iio_push_to_buffers_with_timestamp(indio_dev, &sample, timestamp);
+
+out_done:
+	iio_trigger_notify_done(indio_dev->trig);
+
+	return IRQ_HANDLED;
+}
+
+static const struct regmap_config af8133j_regmap_config = {
+	.name = "af8133j_regmap",
+	.reg_bits = 8,
+	.val_bits = 8,
+	.max_register = AF8133J_REG_SWR,
+	.cache_type = REGCACHE_NONE,
+};
+
+static void af8133j_power_down_action(void *ptr)
+{
+	struct af8133j_data *data = ptr;
+	struct device *dev = &data->client->dev;
+
+	pm_runtime_disable(dev);
+	if (!pm_runtime_status_suspended(dev))
+		af8133j_power_down(data);
+	pm_runtime_enable(dev);
+}
+
+static int af8133j_probe(struct i2c_client *client)
+{
+	struct device *dev = &client->dev;
+	struct af8133j_data *data;
+	struct iio_dev *indio_dev;
+	struct regmap *regmap;
+	int ret, i;
+
+	indio_dev = devm_iio_device_alloc(dev, sizeof(*data));
+	if (!indio_dev)
+		return -ENOMEM;
+
+	regmap = devm_regmap_init_i2c(client, &af8133j_regmap_config);
+	if (IS_ERR(regmap))
+		return dev_err_probe(dev, PTR_ERR(regmap),
+				     "regmap initialization failed\n");
+
+	data = iio_priv(indio_dev);
+	i2c_set_clientdata(client, indio_dev);
+	data->client = client;
+	data->regmap = regmap;
+	data->range = AF8133J_REG_RANGE_12G;
+	mutex_init(&data->mutex);
+
+	data->reset_gpiod = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH);
+	if (IS_ERR(data->reset_gpiod))
+		return dev_err_probe(dev, PTR_ERR(data->reset_gpiod),
+				     "Failed to get reset gpio\n");
+
+	for (i = 0; i < ARRAY_SIZE(af8133j_supply_names); i++)
+		data->supplies[i].supply = af8133j_supply_names[i];
+	ret = devm_regulator_bulk_get(dev, ARRAY_SIZE(data->supplies),
+				      data->supplies);
+	if (ret)
+		return ret;
+
+	ret = iio_read_mount_matrix(dev, &data->orientation);
+	if (ret)
+		return dev_err_probe(dev, ret, "Failed to read mount matrix\n");
+
+	ret = af8133j_power_up(data);
+	if (ret)
+		return ret;
+
+	pm_runtime_set_active(dev);
+
+	ret = devm_add_action_or_reset(dev, af8133j_power_down_action, data);
+	if (ret)
+		return ret;
+
+	ret = af8133j_product_check(data);
+	if (ret)
+		return ret;
+
+	indio_dev->info = &af8133j_info;
+	indio_dev->name = "af8133j";
+	indio_dev->channels = af8133j_channels;
+	indio_dev->num_channels = ARRAY_SIZE(af8133j_channels);
+	indio_dev->modes = INDIO_DIRECT_MODE;
+
+	ret = devm_iio_triggered_buffer_setup(dev, indio_dev, NULL,
+					      &af8133j_trigger_handler, NULL);
+	if (ret < 0)
+		return dev_err_probe(&client->dev, ret,
+				     "Failed to setup iio triggered buffer\n");
+
+	ret = devm_iio_device_register(dev, indio_dev);
+	if (ret)
+		return dev_err_probe(dev, ret, "Failed to register iio device");
+
+	pm_runtime_get_noresume(dev);
+	pm_runtime_use_autosuspend(dev);
+	pm_runtime_set_autosuspend_delay(dev, 500);
+	ret = devm_pm_runtime_enable(dev);
+	if (ret)
+		return ret;
+
+	pm_runtime_put_autosuspend(dev);
+
+	return 0;
+}
+
+static int af8133j_runtime_suspend(struct device *dev)
+{
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	struct af8133j_data *data = iio_priv(indio_dev);
+
+	af8133j_power_down(data);
+
+	return 0;
+}
+
+static int af8133j_runtime_resume(struct device *dev)
+{
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	struct af8133j_data *data = iio_priv(indio_dev);
+
+	return af8133j_power_up(data);
+}
+
+const struct dev_pm_ops af8133j_pm_ops = {
+	SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend, pm_runtime_force_resume)
+	RUNTIME_PM_OPS(af8133j_runtime_suspend, af8133j_runtime_resume, NULL)
+};
+
+static const struct of_device_id af8133j_of_match[] = {
+	{ .compatible = "voltafield,af8133j", },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, af8133j_of_match);
+
+static const struct i2c_device_id af8133j_id[] = {
+	{ "af8133j", 0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, af8133j_id);
+
+static struct i2c_driver af8133j_driver = {
+	.driver = {
+		.name = "af8133j",
+		.of_match_table = af8133j_of_match,
+		.pm = pm_ptr(&af8133j_pm_ops),
+	},
+	.probe = af8133j_probe,
+	.id_table = af8133j_id,
+};
+
+module_i2c_driver(af8133j_driver);
+
+MODULE_AUTHOR("Icenowy Zheng <icenowy@aosc.io>");
+MODULE_AUTHOR("Ondřej Jirman <megi@xff.cz>");
+MODULE_DESCRIPTION("Voltafield AF8133J magnetic sensor driver");
+MODULE_LICENSE("GPL");