Message-ID: <bul6syabdw353oqomcbdz75b56q5yjgslczbw7d6yxfkxvy3hn@3yz3yusfzrlo>
Date: Sat, 17 Feb 2024 20:28:42 +0100
From: Ondřej Jirman <megi@....cz>
To: Jonathan Cameron <jic23@...nel.org>, 
	Lars-Peter Clausen <lars@...afoo.de>, Rob Herring <robh+dt@...nel.org>, 
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>, Conor Dooley <conor+dt@...nel.org>, 
	Andrey Skvortsov <andrej.skvortzov@...il.com>
Cc: Icenowy Zheng <icenowy@...c.io>, Dalton Durst <dalton@...orts.com>, 
	Shoji Keita <awaittrot@...k.jp>, linux-iio@...r.kernel.org, devicetree@...r.kernel.org, 
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 3/4] iio: magnetometer: add a driver for Voltafield
 AF8133J magnetometer

On Fri, Feb 16, 2024 at 07:50:01PM +0100, megi xff wrote:
> From: Icenowy Zheng <icenowy@...c.io>
> 
> AF8133J is a simple I2C-connected magnetometer, without interrupts.
> 
> Add a simple IIO driver for it.
> 
> Co-developed-by: Icenowy Zheng <icenowy@...c.io>
> Signed-off-by: Icenowy Zheng <icenowy@...c.io>
> Signed-off-by: Dalton Durst <dalton@...orts.com>
> Signed-off-by: Shoji Keita <awaittrot@...k.jp>
> Co-developed-by: Ondrej Jirman <megi@....cz>
> Signed-off-by: Ondrej Jirman <megi@....cz>
> Reviewed-by: Andrey Skvortsov <andrej.skvortzov@...il.com>
> Tested-by: Andrey Skvortsov <andrej.skvortzov@...il.com>
> ---
>  drivers/iio/magnetometer/Kconfig   |  12 +
>  drivers/iio/magnetometer/Makefile  |   1 +
>  drivers/iio/magnetometer/af8133j.c | 524 +++++++++++++++++++++++++++++
>  3 files changed, 537 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 @@
>  
>  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..fcb4f0a8e633
> --- /dev/null
> +++ b/drivers/iio/magnetometer/af8133j.c
> @@ -0,0 +1,524 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * af8133j.c - Voltafield AF8133J magnetometer driver
> + *
> + * Copyright 2021 Icenowy Zheng <icenowy@...c.io>
> + * Copyright 2024 Ondřej Jirman <megi@....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) {
> +		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) {
> +			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)
> +		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)
> +		return ret;
> +
> +	ret = regmap_write(data->regmap,
> +			   AF8133J_REG_STATE, AF8133J_REG_STATE_STBY);
> +	if (ret)
> +		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)
> +			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))
> +		scoped_guard(mutex, &data->mutex)
> +			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);
> +
> +	switch (mask) {
> +	case IIO_CHAN_INFO_SCALE:
> +		return af8133j_set_scale(data, val, val2);
> +	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;
> +
> +	if (!pm_runtime_status_suspended(&data->client->dev))
> +		af8133j_power_down(data);
> +}
> +
> +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)
> +		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;

Ah, forgot to move this up. Oh, well. I'll send v4.

kind regards,
	o.

> +	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@...c.io>");
> +MODULE_AUTHOR("Ondřej Jirman <megi@....cz>");
> +MODULE_DESCRIPTION("Voltafield AF8133J magnetic sensor driver");
> +MODULE_LICENSE("GPL");
> -- 
> 2.43.0
> 

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