Support Honeywell mprls0025pa pressure sensor

Honeywell mprls0025pa is a pressure sensor series. There are many different models with different pressure ranges, units and transfer functions.

The range and transfer function need to be set up in the dt. Therefore new properties honeywell,pmin-pascal, honeywell,pmax-pascal, honeywell,transfer-function are introduced.

Add dt-bindings.

Signed-off-by Andreas Klinger <[email protected]>

---
 .../iio/pressure/honeywell,mprls0025pa.yaml   | 104 ++++++++++++++++++
 1 file changed, 104 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/iio/pressure/honeywell,mprls0025pa.yaml

Documentation/devicetree/bindings/iio/pressure/honeywell,mprls0025pa.yaml new file +54 -0

new file mode 100644
index 000000000000..84a61721b597
@@ -0,0 +1,104 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/iio/pressure/honeywell,mprls0025pa.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Honeywell mprls0025pa pressure sensor
+
+maintainers:
+  - Andreas Klinger <[email protected]>
+
+description: |
+  Honeywell pressure sensor of model mprls0025pa.
+
+  This sensor has an I2C and SPI interface. Only the I2C interface is
+  implemented.
+
+  There are many models with different pressure ranges available. The vendor
+  calls them "mpr series". All of them have the identical programming model and
+  differ in the pressure range, unit and transfer function.
+
+  To support different models one need to specify the pressure range as well as
+  the transfer function. Pressure range needs to be converted from its unit to
+  pascal.
+
+  The transfer function defines the ranges of numerical values delivered by the
+  sensor. The minimal range value stands for the minimum pressure and the
+  maximum value also for the maximum pressure with linear relation inside the
+  range.
+
+  Specifications about the devices can be found at:
+    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
+
+properties:
+  compatible:
+    const: honeywell,mprls0025pa
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+
+  reset-gpios:
+    description:
+      Optional GPIO for resetting the device.
+      If not present the device is not resetted during the probe.
+    maxItems: 1
+
+  honeywell,pmin-pascal:
+    description:

Documentation/devicetree/bindings/iio/pressure/honeywell,mprls0025pa.yaml new file +7 -0

+      Transfer function which defines the range of valid values delivered by the
+      sensor.
+      1 - A, 10% to 90% of 2^24 (1677722 .. 15099494)
+      2 - B, 2.5% to 22.5% of 2^24 (419430 .. 3774874)
+      3 - C, 20% to 80% of 2^24 (3355443 .. 13421773)
+    $ref: /schemas/types.yaml#/definitions/uint32
+

Honeywell mprls0025pa is a series of pressure sensors.

Add initial I2C support.

Note:
- IIO buffered mode is supported
- SPI mode is not supported

Signed-off-by Andreas Klinger <[email protected]>

---
 drivers/iio/pressure/Kconfig       |  13 +
 drivers/iio/pressure/Makefile      |   1 +
 drivers/iio/pressure/mprls0025pa.c | 441 +++++++++++++++++++++++++++++
 3 files changed, 455 insertions(+)
 create mode 100644 drivers/iio/pressure/mprls0025pa.c

drivers/iio/pressure/Kconfig +13 -0

index c9453389e4f7..43aef35ce778 100644
@@ -148,6 +148,19 @@ config MPL3115
 	  To compile this driver as a module, choose M here: the module
 	  will be called mpl3115.
 
+config MPRLS0025PA
+	tristate "Honeywell MPRLS0025PA (MicroPressure sensors series)"
+	depends on I2C
+	select IIO_BUFFER
+	select IIO_TRIGGERED_BUFFER
+	help
+	  Say Y here to build support for the Honeywell MicroPressure pressure
+	  sensor series. There are many different types with different pressure
+	  range. These ranges can be set up in the device tree.
+
+	  To compile this driver as a module, choose M here: the module will be
+	  called mprls0025pa.
+
 config MS5611
 	tristate "Measurement Specialties MS5611 pressure sensor driver"
 	select IIO_BUFFER

drivers/iio/pressure/Makefile +1 -0

index 083ae87ff48f..c90f77210e94 100644
@@ -19,6 +19,7 @@ obj-$(CONFIG_MPL115) += mpl115.o
 obj-$(CONFIG_MPL115_I2C) += mpl115_i2c.o
 obj-$(CONFIG_MPL115_SPI) += mpl115_spi.o
 obj-$(CONFIG_MPL3115) += mpl3115.o
+obj-$(CONFIG_MPRLS0025PA) += mprls0025pa.o
 obj-$(CONFIG_MS5611) += ms5611_core.o
 obj-$(CONFIG_MS5611_I2C) += ms5611_i2c.o
 obj-$(CONFIG_MS5611_SPI) += ms5611_spi.o

drivers/iio/pressure/mprls0025pa.c new file +6 -0

new file mode 100644
index 000000000000..7a8736de6e87
@@ -0,0 +1,441 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * MPRLS0025PA - Honeywell MicroPressure pressure sensor series driver
+ *
+ * Copyright (c) Andreas Klinger <[email protected]>
+ *

drivers/iio/pressure/mprls0025pa.c new file +11 -0

+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/gpio/consumer.h>
+#include <linux/i2c.h>
+#include <linux/iio/buffer.h>
+#include <linux/iio/iio.h>
+#include <linux/iio/trigger_consumer.h>
+#include <linux/iio/triggered_buffer.h>
+#include <linux/math64.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>

drivers/iio/pressure/mprls0025pa.c new file +44 -0

+ * Calculation formular 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_OUT_MIN)
+ * * outputmax	- maximum numerical range raw value delivered by sensor
+ *							(MPR_OUT_MAX)
+ * * scale	- (pmax - pmin) / (outputmax - outputmin)
+ *
+ * _RAW interface:
+ * pressure = (raw + offset) * scale
+ * --> need to adjust offset for fitting into _RAW interface
+ * Values for _RAW interface:
+ * * raw	- press_cnt
+ * * scale	- (pmax - pmin) / (outputmax - outputmin)
+ * * 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
+ */
+enum mpr_func_id {
+	MPR_FUNCTION_A,
+	MPR_FUNCTION_B,
+	MPR_FUNCTION_C,
+};
+
+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},

drivers/iio/pressure/mprls0025pa.c new file +4 -0

+	u32			outmin;		/*
+						 * minimal numerical range raw
+						 * value from sensor
+						 */

drivers/iio/pressure/mprls0025pa.c new file +87 -0

+	struct completion	completion;	/* handshake from irq to read */
+	struct mpr_chan		chan;		/*
+						 * channel values for buffered
+						 * mode
+						 */
+};
 
 
+/**
+ * mpr_read_pressure() - Read pressure value from sensor via I2C
+ * @data: Pointer to private data struct.
+ * @press: Output value read from sensor.
+ *
+ * Reading from the sensor by sending and receiving I2C 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->client->dev;
+	int ret, i;
+	u8 wdata[] = {0xAA, 0x00, 0x00};
+	s32 status;
+	int nloops = 10;
+	u8 buf[5];
+
+	reinit_completion(&data->completion);
+
+	ret = i2c_master_send(data->client, wdata, sizeof(wdata));
+	if (ret < 0) {
+		dev_err(dev, "error while writing ret: %d\n", ret);
+		return ret;
+	}
+	if (ret != sizeof(wdata)) {
+		dev_err(dev, "received size doesn't fit - ret: %d / %u\n", ret,
+								sizeof(wdata));
+		return -EIO;
+	}
+
+	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);
+			status = i2c_smbus_read_byte(data->client);
+			if (status < 0) {
+				dev_err(dev,
+					"error while reading, status: %d\n",
+					status);
+				return status;
+			}
+			if (!(status & MPR_I2C_BUSY))
+				break;
+		}
+		if (i == nloops) {
+			dev_err(dev, "timeout while reading\n");
+			return -ETIMEDOUT;
+		}
+	}
+
+	ret = i2c_master_recv(data->client, buf, sizeof(buf));
+	if (ret < 0) {
+		dev_err(dev, "error in i2c_master_recv ret: %d\n", ret);
+		return ret;
+	}
+	if (ret != sizeof(buf)) {
+		dev_err(dev, "received size doesn't fit - ret: %d / %u\n", ret,
+								sizeof(buf));
+		return -EIO;
+	}
+

drivers/iio/pressure/mprls0025pa.c new file +7 -0

+
+	complete(&data->completion);
+
+	return IRQ_HANDLED;
+}
+
+static irqreturn_t mpr_trigger_handler(int irq, void *p)

drivers/iio/pressure/mprls0025pa.c new file +12 -0

+		goto err;
+	}
+
+	iio_push_to_buffers_with_timestamp(indio_dev, &data->chan,
+						iio_get_time_ns(indio_dev));
+	mutex_unlock(&data->lock);
+
+err:
+	iio_trigger_notify_done(indio_dev->trig);
+
+	return IRQ_HANDLED;
+}

drivers/iio/pressure/mprls0025pa.c new file +30 -0

+
+	if (data->irq > 0) {
+		ret = devm_request_irq(dev, data->irq, mpr_eoc_handler,
+				IRQF_TRIGGER_RISING, client->name, 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;
+}

drivers/iio/pressure/mprls0025pa.c line 111

Quoted 6 lines

drivers/iio/pressure/mprls0025pa.c new file +6 -0

+	int                     scale;          /* int part of scale */
+	int                     scale2;         /* nano part of scale */
+	int                     offset;         /* int part of offset */
+	int                     offset2;        /* nano part of offset */
+	struct gpio_desc	*gpiod_reset;	/* reset */
+	int			irq;		/* end of conversion irq */

Only needed in probe, no need for a copy in here.

Hi Jonathan,

thanks for your review. I have one comment.

Jonathan Cameron <[email protected]> schrieb am Sa, 06. Mai 17:04:

Quoted 8 lines

drivers/iio/pressure/mprls0025pa.c line 111

Quoted 6 lines

drivers/iio/pressure/mprls0025pa.c new file +6 -0

+	int                     scale;          /* int part of scale */
+	int                     scale2;         /* nano part of scale */
+	int                     offset;         /* int part of offset */
+	int                     offset2;        /* nano part of offset */
+	struct gpio_desc	*gpiod_reset;	/* reset */
+	int			irq;		/* end of conversion irq */  

Only needed in probe, no need for a copy in here.

It's also used in mpr_read_pressure() to distinguish the two possible operation modes:
- waiting for an interrupt
- reading in a loop until status indicates data ready

Andreas