drivers/iio/pressure/mprls0025pa.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * MPRLS0025PA - Honeywell MicroPressure pressure sensor series driver
  *
  * Copyright (c) Andreas Klinger <ak@it-klinger.de>
  *
  * Data sheet:
  *  https://prod-edam.honeywell.com/content/dam/honeywell-edam/sps/siot/en-us/products/sensors/pressure-sensors/board-mount-pressure-sensors/micropressure-mpr-series/documents/sps-siot-mpr-series-datasheet-32332628-ciid-172626.pdf
  *
  */

 #include <linux/array_size.h>
 #include <linux/bitfield.h>
 #include <linux/bits.h>
 #include <linux/math64.h>
 #include <linux/mod_devicetable.h>
 #include <linux/module.h>
 #include <linux/property.h>
 #include <linux/units.h>

 #include <linux/gpio/consumer.h>

 #include <linux/iio/buffer.h>
 #include <linux/iio/trigger_consumer.h>
 #include <linux/iio/triggered_buffer.h>

 #include <linux/regulator/consumer.h>

 #include <linux/unaligned.h>

 #include "mprls0025pa.h"

 /* bits in status byte */
 #define MPR_ST_POWER  BIT(6) /* device is powered */
 #define MPR_ST_BUSY   BIT(5) /* device is busy */
 #define MPR_ST_MEMORY BIT(2) /* integrity test passed */
 #define MPR_ST_MATH   BIT(0) /* internal math saturation */

 #define MPR_ST_ERR_FLAG  (MPR_ST_BUSY | MPR_ST_MEMORY | MPR_ST_MATH)

 /*
  * support _RAW sysfs interface:
  *
  * Calculation formula from the datasheet:
  * pressure = (press_cnt - outputmin) * scale + pmin
  * with:
  * * pressure	- measured pressure in Pascal
  * * press_cnt	- raw value read from sensor
  * * pmin	- minimum pressure range value of sensor (data->pmin)
  * * pmax	- maximum pressure range value of sensor (data->pmax)
  * * outputmin	- minimum numerical range raw value delivered by sensor
  *						(mpr_func_spec.output_min)
  * * outputmax	- maximum numerical range raw value delivered by sensor
  *						(mpr_func_spec.output_max)
  * * scale	- (pmax - pmin) / (outputmax - outputmin)
  *
  * formula of the userspace:
  * pressure = (raw + offset) * scale
  *
  * Values given to the userspace in sysfs interface:
  * * raw	- press_cnt
  * * offset	- (-1 * outputmin) - pmin / scale
  *                note: With all sensors from the datasheet pmin = 0
  *                which reduces the offset to (-1 * outputmin)
  */

 /*
  * transfer function A: 10%   to 90%   of 2^24
  * transfer function B:  2.5% to 22.5% of 2^24
  * transfer function C: 20%   to 80%   of 2^24
  */
 struct mpr_func_spec {
 	u32			output_min;
 	u32			output_max;
 };

 static const struct mpr_func_spec mpr_func_spec[] = {
 	[MPR_FUNCTION_A] = { .output_min = 1677722, .output_max = 15099494 },
 	[MPR_FUNCTION_B] = { .output_min =  419430, .output_max =  3774874 },
 	[MPR_FUNCTION_C] = { .output_min = 3355443, .output_max = 13421773 },
 };

 enum mpr_variants {
 	MPR0001BA = 0x00, MPR01_6BA = 0x01, MPR02_5BA = 0x02, MPR0060MG = 0x03,
 	MPR0100MG = 0x04, MPR0160MG = 0x05, MPR0250MG = 0x06, MPR0400MG = 0x07,
 	MPR0600MG = 0x08, MPR0001BG = 0x09, MPR01_6BG = 0x0a, MPR02_5BG = 0x0b,
 	MPR0100KA = 0x0c, MPR0160KA = 0x0d, MPR0250KA = 0x0e, MPR0006KG = 0x0f,
 	MPR0010KG = 0x10, MPR0016KG = 0x11, MPR0025KG = 0x12, MPR0040KG = 0x13,
 	MPR0060KG = 0x14, MPR0100KG = 0x15, MPR0160KG = 0x16, MPR0250KG = 0x17,
 	MPR0015PA = 0x18, MPR0025PA = 0x19, MPR0030PA = 0x1a, MPR0001PG = 0x1b,
 	MPR0005PG = 0x1c, MPR0015PG = 0x1d, MPR0030PG = 0x1e, MPR0300YG = 0x1f,
 	MPR_VARIANTS_MAX
 };

 static const char * const mpr_triplet_variants[MPR_VARIANTS_MAX] = {
 	[MPR0001BA] = "0001BA", [MPR01_6BA] = "01.6BA", [MPR02_5BA] = "02.5BA",
 	[MPR0060MG] = "0060MG", [MPR0100MG] = "0100MG", [MPR0160MG] = "0160MG",
 	[MPR0250MG] = "0250MG", [MPR0400MG] = "0400MG", [MPR0600MG] = "0600MG",
 	[MPR0001BG] = "0001BG", [MPR01_6BG] = "01.6BG", [MPR02_5BG] = "02.5BG",
 	[MPR0100KA] = "0100KA", [MPR0160KA] = "0160KA", [MPR0250KA] = "0250KA",
 	[MPR0006KG] = "0006KG", [MPR0010KG] = "0010KG", [MPR0016KG] = "0016KG",
 	[MPR0025KG] = "0025KG", [MPR0040KG] = "0040KG", [MPR0060KG] = "0060KG",
 	[MPR0100KG] = "0100KG", [MPR0160KG] = "0160KG", [MPR0250KG] = "0250KG",
 	[MPR0015PA] = "0015PA", [MPR0025PA] = "0025PA", [MPR0030PA] = "0030PA",
 	[MPR0001PG] = "0001PG", [MPR0005PG] = "0005PG", [MPR0015PG] = "0015PG",
 	[MPR0030PG] = "0030PG", [MPR0300YG] = "0300YG"
 };

 /**
  * struct mpr_range_config - list of pressure ranges based on nomenclature
  * @pmin: lowest pressure that can be measured
  * @pmax: highest pressure that can be measured
  */
 struct mpr_range_config {
 	const s32 pmin;
 	const s32 pmax;
 };

 /* All min max limits have been converted to pascals */
 static const struct mpr_range_config mpr_range_config[MPR_VARIANTS_MAX] = {
 	[MPR0001BA] = { .pmin = 0, .pmax = 100000 },
 	[MPR01_6BA] = { .pmin = 0, .pmax = 160000 },
 	[MPR02_5BA] = { .pmin = 0, .pmax = 250000 },
 	[MPR0060MG] = { .pmin = 0, .pmax =   6000 },
 	[MPR0100MG] = { .pmin = 0, .pmax =  10000 },
 	[MPR0160MG] = { .pmin = 0, .pmax =  16000 },
 	[MPR0250MG] = { .pmin = 0, .pmax =  25000 },
 	[MPR0400MG] = { .pmin = 0, .pmax =  40000 },
 	[MPR0600MG] = { .pmin = 0, .pmax =  60000 },
 	[MPR0001BG] = { .pmin = 0, .pmax = 100000 },
 	[MPR01_6BG] = { .pmin = 0, .pmax = 160000 },
 	[MPR02_5BG] = { .pmin = 0, .pmax = 250000 },
 	[MPR0100KA] = { .pmin = 0, .pmax = 100000 },
 	[MPR0160KA] = { .pmin = 0, .pmax = 160000 },
 	[MPR0250KA] = { .pmin = 0, .pmax = 250000 },
 	[MPR0006KG] = { .pmin = 0, .pmax =   6000 },
 	[MPR0010KG] = { .pmin = 0, .pmax =  10000 },
 	[MPR0016KG] = { .pmin = 0, .pmax =  16000 },
 	[MPR0025KG] = { .pmin = 0, .pmax =  25000 },
 	[MPR0040KG] = { .pmin = 0, .pmax =  40000 },
 	[MPR0060KG] = { .pmin = 0, .pmax =  60000 },
 	[MPR0100KG] = { .pmin = 0, .pmax = 100000 },
 	[MPR0160KG] = { .pmin = 0, .pmax = 160000 },
 	[MPR0250KG] = { .pmin = 0, .pmax = 250000 },
 	[MPR0015PA] = { .pmin = 0, .pmax = 103421 },
 	[MPR0025PA] = { .pmin = 0, .pmax = 172369 },
 	[MPR0030PA] = { .pmin = 0, .pmax = 206843 },
 	[MPR0001PG] = { .pmin = 0, .pmax =   6895 },
 	[MPR0005PG] = { .pmin = 0, .pmax =  34474 },
 	[MPR0015PG] = { .pmin = 0, .pmax = 103421 },
 	[MPR0030PG] = { .pmin = 0, .pmax = 206843 },
 	[MPR0300YG] = { .pmin = 0, .pmax =  39997 }
 };

 static const struct iio_chan_spec mpr_channels[] = {
 	{
 		.type = IIO_PRESSURE,
 		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
 					BIT(IIO_CHAN_INFO_SCALE) |
 					BIT(IIO_CHAN_INFO_OFFSET),
 		.scan_index = 0,
 		.scan_type = {
 			.sign = 's',
 			.realbits = 32,
 			.storagebits = 32,
 			.endianness = IIO_CPU,
 		},
 	},
 	IIO_CHAN_SOFT_TIMESTAMP(1),
 };

 static void mpr_reset(struct mpr_data *data)
 {
 	if (data->gpiod_reset) {
 		gpiod_set_value(data->gpiod_reset, 0);
 		udelay(10);
 		gpiod_set_value(data->gpiod_reset, 1);
 	}
 }

 /**
  * mpr_read_pressure() - Read pressure value from sensor
  * @data: Pointer to private data struct.
  * @press: Output value read from sensor.
  *
  * Reading from the sensor by sending and receiving telegrams.
  *
  * If there is an end of conversion (EOC) interrupt registered the function
  * waits for a maximum of one second for the interrupt.
  *
  * Context: The function can sleep and data->lock should be held when calling it
  * Return:
  * * 0		- OK, the pressure value could be read
  * * -ETIMEDOUT	- Timeout while waiting for the EOC interrupt or busy flag is
  *		  still set after nloops attempts of reading
  */
 static int mpr_read_pressure(struct mpr_data *data, s32 *press)
 {
 	struct device *dev = data->dev;
 	int ret, i;
 	int nloops = 10;

 	reinit_completion(&data->completion);

 	ret = data->ops->write(data, MPR_CMD_SYNC, MPR_PKT_SYNC_LEN);
 	if (ret < 0) {
 		dev_err(dev, "error while writing ret: %d\n", ret);
 		return ret;
 	}

 	if (data->irq > 0) {
 		ret = wait_for_completion_timeout(&data->completion, HZ);
 		if (!ret) {
 			dev_err(dev, "timeout while waiting for eoc irq\n");
 			return -ETIMEDOUT;
 		}
 	} else {
 		/* wait until status indicates data is ready */
 		for (i = 0; i < nloops; i++) {
 			/*
 			 * datasheet only says to wait at least 5 ms for the
 			 * data but leave the maximum response time open
 			 * --> let's try it nloops (10) times which seems to be
 			 *     quite long
 			 */
 			usleep_range(5000, 10000);
 			ret = data->ops->read(data, MPR_CMD_NOP, 1);
 			if (ret < 0) {
 				dev_err(dev,
 					"error while reading, status: %d\n",
 					ret);
 				return ret;
 			}
 			if (!(data->buffer[0] & MPR_ST_ERR_FLAG))
 				break;
 		}
 		if (i == nloops) {
 			dev_err(dev, "timeout while reading\n");
 			return -ETIMEDOUT;
 		}
 	}

 	ret = data->ops->read(data, MPR_CMD_NOP, MPR_PKT_NOP_LEN);
 	if (ret < 0)
 		return ret;

 	if (data->buffer[0] & MPR_ST_ERR_FLAG) {
 		dev_err(data->dev,
 			"unexpected status byte %02x\n", data->buffer[0]);
 		return -ETIMEDOUT;
 	}

 	*press = get_unaligned_be24(&data->buffer[1]);

 	dev_dbg(dev, "received: %*ph cnt: %d\n", ret, data->buffer, *press);

 	return 0;
 }

 static irqreturn_t mpr_eoc_handler(int irq, void *p)
 {
 	struct mpr_data *data = p;

 	complete(&data->completion);

 	return IRQ_HANDLED;
 }

 static irqreturn_t mpr_trigger_handler(int irq, void *p)
 {
 	int ret;
 	struct iio_poll_func *pf = p;
 	struct iio_dev *indio_dev = pf->indio_dev;
 	struct mpr_data *data = iio_priv(indio_dev);

 	mutex_lock(&data->lock);
 	ret = mpr_read_pressure(data, &data->chan.pres);
 	if (ret < 0)
 		goto err;

 	iio_push_to_buffers_with_timestamp(indio_dev, &data->chan,
 					   iio_get_time_ns(indio_dev));

 err:
 	mutex_unlock(&data->lock);
 	iio_trigger_notify_done(indio_dev->trig);

 	return IRQ_HANDLED;
 }

 static int mpr_read_raw(struct iio_dev *indio_dev,
 	struct iio_chan_spec const *chan, int *val, int *val2, long mask)
 {
 	int ret;
 	s32 pressure;
 	struct mpr_data *data = iio_priv(indio_dev);

 	if (chan->type != IIO_PRESSURE)
 		return -EINVAL;

 	switch (mask) {
 	case IIO_CHAN_INFO_RAW:
 		mutex_lock(&data->lock);
 		ret = mpr_read_pressure(data, &pressure);
 		mutex_unlock(&data->lock);
 		if (ret < 0)
 			return ret;
 		*val = pressure;
 		return IIO_VAL_INT;
 	case IIO_CHAN_INFO_SCALE:
 		*val = data->scale;
 		*val2 = data->scale2;
 		return IIO_VAL_INT_PLUS_NANO;
 	case IIO_CHAN_INFO_OFFSET:
 		*val = data->offset;
 		*val2 = data->offset2;
 		return IIO_VAL_INT_PLUS_NANO;
 	default:
 		return -EINVAL;
 	}
 }

 static const struct iio_info mpr_info = {
 	.read_raw = &mpr_read_raw,
 };

 int mpr_common_probe(struct device *dev, const struct mpr_ops *ops, int irq)
 {
 	int ret;
 	struct mpr_data *data;
 	struct iio_dev *indio_dev;
 	const char *triplet;
 	s64 scale, offset;
 	u32 func;

 	indio_dev = devm_iio_device_alloc(dev, sizeof(*data));
 	if (!indio_dev)
 		return -ENOMEM;

 	data = iio_priv(indio_dev);
 	data->dev = dev;
 	data->ops = ops;
 	data->irq = irq;

 	mutex_init(&data->lock);
 	init_completion(&data->completion);

 	indio_dev->name = "mprls0025pa";
 	indio_dev->info = &mpr_info;
 	indio_dev->channels = mpr_channels;
 	indio_dev->num_channels = ARRAY_SIZE(mpr_channels);
 	indio_dev->modes = INDIO_DIRECT_MODE;

 	ret = devm_regulator_get_enable(dev, "vdd");
 	if (ret)
 		return dev_err_probe(dev, ret,
 				     "can't get and enable vdd supply\n");

 	ret = data->ops->init(data->dev);
 	if (ret)
 		return ret;

 	ret = device_property_read_u32(dev,
 				       "honeywell,transfer-function", &func);
 	if (ret)
 		return dev_err_probe(dev, ret,
 			     "honeywell,transfer-function could not be read\n");
 	data->function = func - 1;
 	if (data->function > MPR_FUNCTION_C)
 		return dev_err_probe(dev, -EINVAL,
 				     "honeywell,transfer-function %d invalid\n",
 				     data->function);

 	ret = device_property_read_string(dev, "honeywell,pressure-triplet",
 					  &triplet);
 	if (ret) {
 		ret = device_property_read_u32(dev, "honeywell,pmin-pascal",
 					       &data->pmin);
 		if (ret)
 			return dev_err_probe(dev, ret,
 				   "honeywell,pmin-pascal could not be read\n");

 		ret = device_property_read_u32(dev, "honeywell,pmax-pascal",
 					       &data->pmax);
 		if (ret)
 			return dev_err_probe(dev, ret,
 				   "honeywell,pmax-pascal could not be read\n");
 	} else {
 		ret = device_property_match_property_string(dev,
 						   "honeywell,pressure-triplet",
 						   mpr_triplet_variants,
 						   MPR_VARIANTS_MAX);
 		if (ret < 0)
 			return dev_err_probe(dev, -EINVAL,
 				     "honeywell,pressure-triplet is invalid\n");

 		data->pmin = mpr_range_config[ret].pmin;
 		data->pmax = mpr_range_config[ret].pmax;
 	}

 	if (data->pmin >= data->pmax)
 		return dev_err_probe(dev, -EINVAL,
 				     "pressure limits are invalid\n");

 	data->outmin = mpr_func_spec[data->function].output_min;
 	data->outmax = mpr_func_spec[data->function].output_max;

 	/* use 64 bit calculation for preserving a reasonable precision */
 	scale = div_s64(((s64)(data->pmax - data->pmin)) * NANO,
 			data->outmax - data->outmin);
 	data->scale = div_s64_rem(scale, NANO, &data->scale2);
 	/*
 	 * multiply with NANO before dividing by scale and later divide by NANO
 	 * again.
 	 */
 	offset = ((-1LL) * (s64)data->outmin) * NANO -
 		  div_s64(div_s64((s64)data->pmin * NANO, scale), NANO);
 	data->offset = div_s64_rem(offset, NANO, &data->offset2);

 	if (data->irq > 0) {
 		ret = devm_request_irq(dev, data->irq, mpr_eoc_handler,
 				       IRQF_TRIGGER_RISING,
 				       dev_name(dev),
 				       data);
 		if (ret)
 			return dev_err_probe(dev, ret,
 					  "request irq %d failed\n", data->irq);
 	}

 	data->gpiod_reset = devm_gpiod_get_optional(dev, "reset",
 						    GPIOD_OUT_HIGH);
 	if (IS_ERR(data->gpiod_reset))
 		return dev_err_probe(dev, PTR_ERR(data->gpiod_reset),
 				     "request reset-gpio failed\n");

 	mpr_reset(data);

 	ret = devm_iio_triggered_buffer_setup(dev, indio_dev, NULL,
 					      mpr_trigger_handler, NULL);
 	if (ret)
 		return dev_err_probe(dev, ret,
 				     "iio triggered buffer setup failed\n");

 	ret = devm_iio_device_register(dev, indio_dev);
 	if (ret)
 		return dev_err_probe(dev, ret,
 				     "unable to register iio device\n");

 	return 0;
 }
 EXPORT_SYMBOL_NS(mpr_common_probe, IIO_HONEYWELL_MPRLS0025PA);

 MODULE_AUTHOR("Andreas Klinger <ak@it-klinger.de>");
 MODULE_DESCRIPTION("Honeywell MPR pressure sensor core driver");
 MODULE_LICENSE("GPL");
	// SPDX-License-Identifier: GPL-2.0-or-later
	/*
	* MPRLS0025PA - Honeywell MicroPressure pressure sensor series driver
	*
	* Copyright (c) Andreas Klinger <ak@it-klinger.de>
	*
	* Data sheet:
	* https://prod-edam.honeywell.com/content/dam/honeywell-edam/sps/siot/en-us/products/sensors/pressure-sensors/board-mount-pressure-sensors/micropressure-mpr-series/documents/sps-siot-mpr-series-datasheet-32332628-ciid-172626.pdf
	*
	*/

	#include <linux/array_size.h>
	#include <linux/bitfield.h>
	#include <linux/bits.h>
	#include <linux/math64.h>
	#include <linux/mod_devicetable.h>
	#include <linux/module.h>
	#include <linux/property.h>
	#include <linux/units.h>

	#include <linux/gpio/consumer.h>

	#include <linux/iio/buffer.h>
	#include <linux/iio/trigger_consumer.h>
	#include <linux/iio/triggered_buffer.h>

	#include <linux/regulator/consumer.h>

	#include <linux/unaligned.h>

	#include "mprls0025pa.h"

	/* bits in status byte */
	#define MPR_ST_POWER BIT(6) /* device is powered */
	#define MPR_ST_BUSY BIT(5) /* device is busy */
	#define MPR_ST_MEMORY BIT(2) /* integrity test passed */
	#define MPR_ST_MATH BIT(0) /* internal math saturation */

	#define MPR_ST_ERR_FLAG (MPR_ST_BUSY \| MPR_ST_MEMORY \| MPR_ST_MATH)

	/*
	* support _RAW sysfs interface:
	*
	* Calculation formula from the datasheet:
	* pressure = (press_cnt - outputmin) * scale + pmin
	* with:
	* * pressure - measured pressure in Pascal
	* * press_cnt - raw value read from sensor
	* * pmin - minimum pressure range value of sensor (data->pmin)
	* * pmax - maximum pressure range value of sensor (data->pmax)
	* * outputmin - minimum numerical range raw value delivered by sensor
	* (mpr_func_spec.output_min)
	* * outputmax - maximum numerical range raw value delivered by sensor
	* (mpr_func_spec.output_max)
	* * scale - (pmax - pmin) / (outputmax - outputmin)
	*
	* formula of the userspace:
	* pressure = (raw + offset) * scale
	*
	* Values given to the userspace in sysfs interface:
	* * raw - press_cnt
	* * offset - (-1 * outputmin) - pmin / scale
	* note: With all sensors from the datasheet pmin = 0
	* which reduces the offset to (-1 * outputmin)
	*/

	/*
	* transfer function A: 10% to 90% of 2^24
	* transfer function B: 2.5% to 22.5% of 2^24
	* transfer function C: 20% to 80% of 2^24
	*/
	struct mpr_func_spec {
	u32 output_min;
	u32 output_max;
	};

	static const struct mpr_func_spec mpr_func_spec[] = {
	[MPR_FUNCTION_A] = { .output_min = 1677722, .output_max = 15099494 },
	[MPR_FUNCTION_B] = { .output_min = 419430, .output_max = 3774874 },
	[MPR_FUNCTION_C] = { .output_min = 3355443, .output_max = 13421773 },
	};

	enum mpr_variants {
	MPR0001BA = 0x00, MPR01_6BA = 0x01, MPR02_5BA = 0x02, MPR0060MG = 0x03,
	MPR0100MG = 0x04, MPR0160MG = 0x05, MPR0250MG = 0x06, MPR0400MG = 0x07,
	MPR0600MG = 0x08, MPR0001BG = 0x09, MPR01_6BG = 0x0a, MPR02_5BG = 0x0b,
	MPR0100KA = 0x0c, MPR0160KA = 0x0d, MPR0250KA = 0x0e, MPR0006KG = 0x0f,
	MPR0010KG = 0x10, MPR0016KG = 0x11, MPR0025KG = 0x12, MPR0040KG = 0x13,
	MPR0060KG = 0x14, MPR0100KG = 0x15, MPR0160KG = 0x16, MPR0250KG = 0x17,
	MPR0015PA = 0x18, MPR0025PA = 0x19, MPR0030PA = 0x1a, MPR0001PG = 0x1b,
	MPR0005PG = 0x1c, MPR0015PG = 0x1d, MPR0030PG = 0x1e, MPR0300YG = 0x1f,
	MPR_VARIANTS_MAX
	};

	static const char * const mpr_triplet_variants[MPR_VARIANTS_MAX] = {
	[MPR0001BA] = "0001BA", [MPR01_6BA] = "01.6BA", [MPR02_5BA] = "02.5BA",
	[MPR0060MG] = "0060MG", [MPR0100MG] = "0100MG", [MPR0160MG] = "0160MG",
	[MPR0250MG] = "0250MG", [MPR0400MG] = "0400MG", [MPR0600MG] = "0600MG",
	[MPR0001BG] = "0001BG", [MPR01_6BG] = "01.6BG", [MPR02_5BG] = "02.5BG",
	[MPR0100KA] = "0100KA", [MPR0160KA] = "0160KA", [MPR0250KA] = "0250KA",
	[MPR0006KG] = "0006KG", [MPR0010KG] = "0010KG", [MPR0016KG] = "0016KG",
	[MPR0025KG] = "0025KG", [MPR0040KG] = "0040KG", [MPR0060KG] = "0060KG",
	[MPR0100KG] = "0100KG", [MPR0160KG] = "0160KG", [MPR0250KG] = "0250KG",
	[MPR0015PA] = "0015PA", [MPR0025PA] = "0025PA", [MPR0030PA] = "0030PA",
	[MPR0001PG] = "0001PG", [MPR0005PG] = "0005PG", [MPR0015PG] = "0015PG",
	[MPR0030PG] = "0030PG", [MPR0300YG] = "0300YG"
	};

	/**
	* struct mpr_range_config - list of pressure ranges based on nomenclature
	* @pmin: lowest pressure that can be measured
	* @pmax: highest pressure that can be measured
	*/
	struct mpr_range_config {
	const s32 pmin;
	const s32 pmax;
	};

	/* All min max limits have been converted to pascals */
	static const struct mpr_range_config mpr_range_config[MPR_VARIANTS_MAX] = {
	[MPR0001BA] = { .pmin = 0, .pmax = 100000 },
	[MPR01_6BA] = { .pmin = 0, .pmax = 160000 },
	[MPR02_5BA] = { .pmin = 0, .pmax = 250000 },
	[MPR0060MG] = { .pmin = 0, .pmax = 6000 },
	[MPR0100MG] = { .pmin = 0, .pmax = 10000 },
	[MPR0160MG] = { .pmin = 0, .pmax = 16000 },
	[MPR0250MG] = { .pmin = 0, .pmax = 25000 },
	[MPR0400MG] = { .pmin = 0, .pmax = 40000 },
	[MPR0600MG] = { .pmin = 0, .pmax = 60000 },
	[MPR0001BG] = { .pmin = 0, .pmax = 100000 },
	[MPR01_6BG] = { .pmin = 0, .pmax = 160000 },
	[MPR02_5BG] = { .pmin = 0, .pmax = 250000 },
	[MPR0100KA] = { .pmin = 0, .pmax = 100000 },
	[MPR0160KA] = { .pmin = 0, .pmax = 160000 },
	[MPR0250KA] = { .pmin = 0, .pmax = 250000 },
	[MPR0006KG] = { .pmin = 0, .pmax = 6000 },
	[MPR0010KG] = { .pmin = 0, .pmax = 10000 },
	[MPR0016KG] = { .pmin = 0, .pmax = 16000 },
	[MPR0025KG] = { .pmin = 0, .pmax = 25000 },
	[MPR0040KG] = { .pmin = 0, .pmax = 40000 },
	[MPR0060KG] = { .pmin = 0, .pmax = 60000 },
	[MPR0100KG] = { .pmin = 0, .pmax = 100000 },
	[MPR0160KG] = { .pmin = 0, .pmax = 160000 },
	[MPR0250KG] = { .pmin = 0, .pmax = 250000 },
	[MPR0015PA] = { .pmin = 0, .pmax = 103421 },
	[MPR0025PA] = { .pmin = 0, .pmax = 172369 },
	[MPR0030PA] = { .pmin = 0, .pmax = 206843 },
	[MPR0001PG] = { .pmin = 0, .pmax = 6895 },
	[MPR0005PG] = { .pmin = 0, .pmax = 34474 },
	[MPR0015PG] = { .pmin = 0, .pmax = 103421 },
	[MPR0030PG] = { .pmin = 0, .pmax = 206843 },
	[MPR0300YG] = { .pmin = 0, .pmax = 39997 }
	};

	static const struct iio_chan_spec mpr_channels[] = {
	{
	.type = IIO_PRESSURE,
	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) \|
	BIT(IIO_CHAN_INFO_SCALE) \|
	BIT(IIO_CHAN_INFO_OFFSET),
	.scan_index = 0,
	.scan_type = {
	.sign = 's',
	.realbits = 32,
	.storagebits = 32,
	.endianness = IIO_CPU,
	},
	},
	IIO_CHAN_SOFT_TIMESTAMP(1),
	};

	static void mpr_reset(struct mpr_data *data)
	{
	if (data->gpiod_reset) {
	gpiod_set_value(data->gpiod_reset, 0);
	udelay(10);
	gpiod_set_value(data->gpiod_reset, 1);
	}
	}

	/**
	* mpr_read_pressure() - Read pressure value from sensor
	* @data: Pointer to private data struct.
	* @press: Output value read from sensor.
	*
	* Reading from the sensor by sending and receiving telegrams.
	*
	* If there is an end of conversion (EOC) interrupt registered the function
	* waits for a maximum of one second for the interrupt.
	*
	* Context: The function can sleep and data->lock should be held when calling it
	* Return:
	* * 0 - OK, the pressure value could be read
	* * -ETIMEDOUT - Timeout while waiting for the EOC interrupt or busy flag is
	* still set after nloops attempts of reading
	*/
	static int mpr_read_pressure(struct mpr_data data, s32 press)
	{
	struct device *dev = data->dev;
	int ret, i;
	int nloops = 10;

	reinit_completion(&data->completion);

	ret = data->ops->write(data, MPR_CMD_SYNC, MPR_PKT_SYNC_LEN);
	if (ret < 0) {
	dev_err(dev, "error while writing ret: %d\n", ret);
	return ret;
	}

	if (data->irq > 0) {
	ret = wait_for_completion_timeout(&data->completion, HZ);
	if (!ret) {
	dev_err(dev, "timeout while waiting for eoc irq\n");
	return -ETIMEDOUT;
	}
	} else {
	/* wait until status indicates data is ready */
	for (i = 0; i < nloops; i++) {
	/*
	* datasheet only says to wait at least 5 ms for the
	* data but leave the maximum response time open
	* --> let's try it nloops (10) times which seems to be
	* quite long
	*/
	usleep_range(5000, 10000);
	ret = data->ops->read(data, MPR_CMD_NOP, 1);
	if (ret < 0) {
	dev_err(dev,
	"error while reading, status: %d\n",
	ret);
	return ret;
	}
	if (!(data->buffer[0] & MPR_ST_ERR_FLAG))
	break;
	}
	if (i == nloops) {
	dev_err(dev, "timeout while reading\n");
	return -ETIMEDOUT;
	}
	}

	ret = data->ops->read(data, MPR_CMD_NOP, MPR_PKT_NOP_LEN);
	if (ret < 0)
	return ret;

	if (data->buffer[0] & MPR_ST_ERR_FLAG) {
	dev_err(data->dev,
	"unexpected status byte %02x\n", data->buffer[0]);
	return -ETIMEDOUT;
	}

	*press = get_unaligned_be24(&data->buffer[1]);

	dev_dbg(dev, "received: %ph cnt: %d\n", ret, data->buffer, press);

	return 0;
	}

	static irqreturn_t mpr_eoc_handler(int irq, void *p)
	{
	struct mpr_data *data = p;

	complete(&data->completion);

	return IRQ_HANDLED;
	}

	static irqreturn_t mpr_trigger_handler(int irq, void *p)
	{
	int ret;
	struct iio_poll_func *pf = p;
	struct iio_dev *indio_dev = pf->indio_dev;
	struct mpr_data *data = iio_priv(indio_dev);

	mutex_lock(&data->lock);
	ret = mpr_read_pressure(data, &data->chan.pres);
	if (ret < 0)
	goto err;

	iio_push_to_buffers_with_timestamp(indio_dev, &data->chan,
	iio_get_time_ns(indio_dev));

	err:
	mutex_unlock(&data->lock);
	iio_trigger_notify_done(indio_dev->trig);

	return IRQ_HANDLED;
	}

	static int mpr_read_raw(struct iio_dev *indio_dev,
	struct iio_chan_spec const chan, int val, int *val2, long mask)
	{
	int ret;
	s32 pressure;
	struct mpr_data *data = iio_priv(indio_dev);

	if (chan->type != IIO_PRESSURE)
	return -EINVAL;

	switch (mask) {
	case IIO_CHAN_INFO_RAW:
	mutex_lock(&data->lock);
	ret = mpr_read_pressure(data, &pressure);
	mutex_unlock(&data->lock);
	if (ret < 0)
	return ret;
	*val = pressure;
	return IIO_VAL_INT;
	case IIO_CHAN_INFO_SCALE:
	*val = data->scale;
	*val2 = data->scale2;
	return IIO_VAL_INT_PLUS_NANO;
	case IIO_CHAN_INFO_OFFSET:
	*val = data->offset;
	*val2 = data->offset2;
	return IIO_VAL_INT_PLUS_NANO;
	default:
	return -EINVAL;
	}
	}

	static const struct iio_info mpr_info = {
	.read_raw = &mpr_read_raw,
	};

	int mpr_common_probe(struct device dev, const struct mpr_ops ops, int irq)
	{
	int ret;
	struct mpr_data *data;
	struct iio_dev *indio_dev;
	const char *triplet;
	s64 scale, offset;
	u32 func;

	indio_dev = devm_iio_device_alloc(dev, sizeof(*data));
	if (!indio_dev)
	return -ENOMEM;

	data = iio_priv(indio_dev);
	data->dev = dev;
	data->ops = ops;
	data->irq = irq;

	mutex_init(&data->lock);
	init_completion(&data->completion);

	indio_dev->name = "mprls0025pa";
	indio_dev->info = &mpr_info;
	indio_dev->channels = mpr_channels;
	indio_dev->num_channels = ARRAY_SIZE(mpr_channels);
	indio_dev->modes = INDIO_DIRECT_MODE;

	ret = devm_regulator_get_enable(dev, "vdd");
	if (ret)
	return dev_err_probe(dev, ret,
	"can't get and enable vdd supply\n");

	ret = data->ops->init(data->dev);
	if (ret)
	return ret;

	ret = device_property_read_u32(dev,
	"honeywell,transfer-function", &func);
	if (ret)
	return dev_err_probe(dev, ret,
	"honeywell,transfer-function could not be read\n");
	data->function = func - 1;
	if (data->function > MPR_FUNCTION_C)
	return dev_err_probe(dev, -EINVAL,
	"honeywell,transfer-function %d invalid\n",
	data->function);

	ret = device_property_read_string(dev, "honeywell,pressure-triplet",
	&triplet);
	if (ret) {
	ret = device_property_read_u32(dev, "honeywell,pmin-pascal",
	&data->pmin);
	if (ret)
	return dev_err_probe(dev, ret,
	"honeywell,pmin-pascal could not be read\n");

	ret = device_property_read_u32(dev, "honeywell,pmax-pascal",
	&data->pmax);
	if (ret)
	return dev_err_probe(dev, ret,
	"honeywell,pmax-pascal could not be read\n");
	} else {
	ret = device_property_match_property_string(dev,
	"honeywell,pressure-triplet",
	mpr_triplet_variants,
	MPR_VARIANTS_MAX);
	if (ret < 0)
	return dev_err_probe(dev, -EINVAL,
	"honeywell,pressure-triplet is invalid\n");

	data->pmin = mpr_range_config[ret].pmin;
	data->pmax = mpr_range_config[ret].pmax;
	}

	if (data->pmin >= data->pmax)
	return dev_err_probe(dev, -EINVAL,
	"pressure limits are invalid\n");

	data->outmin = mpr_func_spec[data->function].output_min;
	data->outmax = mpr_func_spec[data->function].output_max;

	/* use 64 bit calculation for preserving a reasonable precision */
	scale = div_s64(((s64)(data->pmax - data->pmin)) * NANO,
	data->outmax - data->outmin);
	data->scale = div_s64_rem(scale, NANO, &data->scale2);
	/*
	* multiply with NANO before dividing by scale and later divide by NANO
	* again.
	*/
	offset = ((-1LL) * (s64)data->outmin) * NANO -
	div_s64(div_s64((s64)data->pmin * NANO, scale), NANO);
	data->offset = div_s64_rem(offset, NANO, &data->offset2);

	if (data->irq > 0) {
	ret = devm_request_irq(dev, data->irq, mpr_eoc_handler,
	IRQF_TRIGGER_RISING,
	dev_name(dev),
	data);
	if (ret)
	return dev_err_probe(dev, ret,
	"request irq %d failed\n", data->irq);
	}

	data->gpiod_reset = devm_gpiod_get_optional(dev, "reset",
	GPIOD_OUT_HIGH);
	if (IS_ERR(data->gpiod_reset))
	return dev_err_probe(dev, PTR_ERR(data->gpiod_reset),
	"request reset-gpio failed\n");

	mpr_reset(data);

	ret = devm_iio_triggered_buffer_setup(dev, indio_dev, NULL,
	mpr_trigger_handler, NULL);
	if (ret)
	return dev_err_probe(dev, ret,
	"iio triggered buffer setup failed\n");

	ret = devm_iio_device_register(dev, indio_dev);
	if (ret)
	return dev_err_probe(dev, ret,
	"unable to register iio device\n");

	return 0;
	}
	EXPORT_SYMBOL_NS(mpr_common_probe, IIO_HONEYWELL_MPRLS0025PA);

	MODULE_AUTHOR("Andreas Klinger <ak@it-klinger.de>");
	MODULE_DESCRIPTION("Honeywell MPR pressure sensor core driver");
	MODULE_LICENSE("GPL");