[PATCH v5 0/3] Support Honeywell mprls0025pa pressure sensor

[PATCH v5 0/3] Support Honeywell mprls0025pa pressure sensor

[Andreas Klinger]

Support Honeywell mprls0025pa pressure sensor.

This patch series adds support for Honeywell mprls0025pa pressure sensor series.
There are a variety of sensors with different pressure ranges supported.

Changes in v5:
- Patch 1: "dt-bindings: iio: pressure: Support Honeywell mprls0025pa sensor"
  - add Reviewd-by tag
  - preserve formating in description
- Patch 2: "iio: pressure: Honeywell mprls0025pa pressure sensor"
  - make use of div_s64_rem()
  - document calculation
  - reorder includes
  - use NANO from units.h
- Patch 3: "MAINTAINERS: Add Honeywell mprls0025pa sensor"
  - no changes

Changes in v4:
- Patch 1: "dt-bindings: iio: pressure: Support Honeywell mprls0025pa sensor"
  - change line length to 80 characters
  - make vdd-supply mandatory
- Patch 2: "iio: pressure: Honeywell mprls0025pa pressure sensor"
  - change line length to 80 characters
  - change regulator vcc to devm_regulator_get_enable()
  - switch to probe_new
  - many changes from the review
- Patch 3: "MAINTAINERS: Add Honeywell mprls0025pa sensor"
  - no changes

Changes in v3:
- Patch 1: "dt-bindings: iio: pressure: Support Honeywell mprls0025pa sensor"
  - fix errors while doing dt_binding_check
  - add vdd-supply
- Patch 2: "iio: pressure: Honeywell mpr pressure sensor"
  - change to _RAW interface
  - add transfer function
  - add regulator
  - move to device_property_xxx functions
  - many more changes from the feedbacks
- Patch 3: "MAINTAINERS: Add Honeywell mpr sensor"
  - change file names

Changes in v2:
- Patch 1: "dt-bindings: iio: pressure: Support Honeywell mprls0025pa sensor"
  - change the global sensor decription of mpr to the specific sensor
    mprls0025pa
  - change compatible string
  - rename the file to honeywell,mprls0025pa.yaml
  - honeywell,pmin-pascal and honeywell,pmax-pascal: add unit pascal to property
    names 
  - add new property honeywell,transfer-function
- Patch 2: "iio: pressure: Honeywell mpr pressure sensor"
  - no change so far
  - will be changed and send out as new version when the dt definition is
    settled down
- Patch 3: "MAINTAINERS: Add Honeywell mpr sensor"
  - no change so far

Andreas Klinger (3):
  dt-bindings: iio: pressure: Support Honeywell mprls0025pa sensor
  iio: pressure: Honeywell mprls0025pa pressure sensor
  MAINTAINERS: Add Honeywell mprls0025pa sensor

 .../iio/pressure/honeywell,mprls0025pa.yaml   | 104 ++++
 MAINTAINERS                                   |   7 +
 drivers/iio/pressure/Kconfig                  |  13 +
 drivers/iio/pressure/Makefile                 |   1 +
 drivers/iio/pressure/mprls0025pa.c            | 450 ++++++++++++++++++
 5 files changed, 575 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/iio/pressure/honeywell,mprls0025pa.yaml
 create mode 100644 drivers/iio/pressure/mprls0025pa.c


base-commit: 457391b0380335d5e9a5babdec90ac53928b23b4
-- 
2.30.2

[PATCH v5 1/3] dt-bindings: iio: pressure: Support Honeywell mprls0025pa sensor

[Andreas Klinger]

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.

Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Andreas Klinger <ak@it-klinger.de>
---
 .../iio/pressure/honeywell,mprls0025pa.yaml   | 104 ++++++++++++++++++
 1 file changed, 104 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/iio/pressure/honeywell,mprls0025pa.yaml

diff --git a/Documentation/devicetree/bindings/iio/pressure/honeywell,mprls0025pa.yaml b/Documentation/devicetree/bindings/iio/pressure/honeywell,mprls0025pa.yaml
new file mode 100644
index 000000000000..c0a923febf13
--- /dev/null
+++ b/Documentation/devicetree/bindings/iio/pressure/honeywell,mprls0025pa.yaml
@@ -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 <ak@it-klinger.de>
+
+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:
+      Minimum pressure value the sensor can measure in pascal.
+    $ref: /schemas/types.yaml#/definitions/uint32
+
+  honeywell,pmax-pascal:
+    description:
+      Maximum pressure value the sensor can measure in pascal.
+    $ref: /schemas/types.yaml#/definitions/uint32
+
+  honeywell,transfer-function:
+    description: |
+      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
+
+  vdd-supply:
+    description: provide VDD power to the sensor.
+
+required:
+  - compatible
+  - reg
+  - honeywell,pmin-pascal
+  - honeywell,pmax-pascal
+  - honeywell,transfer-function
+  - vdd-supply
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/gpio/gpio.h>
+    #include <dt-bindings/interrupt-controller/irq.h>
+    i2c {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        pressure@18 {
+            compatible = "honeywell,mprls0025pa";
+            reg = <0x18>;
+            reset-gpios = <&gpio3 19 GPIO_ACTIVE_HIGH>;
+            interrupt-parent = <&gpio3>;
+            interrupts = <21 IRQ_TYPE_EDGE_FALLING>;
+            honeywell,pmin-pascal = <0>;
+            honeywell,pmax-pascal = <172369>;
+            honeywell,transfer-function = <1>;
+            vdd-supply = <&vcc_3v3>;
+        };
+    };
-- 
2.30.2


-- 
Andreas Klinger
Grabenreith 27
84508 Burgkirchen
+49 8623 919966
ak@it-klinger.de
www.it-klinger.de
www.grabenreith.de

[PATCH v5 2/3] iio: pressure: Honeywell mprls0025pa pressure sensor

[Andreas Klinger]

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 <ak@it-klinger.de>
---
 drivers/iio/pressure/Kconfig       |  13 +
 drivers/iio/pressure/Makefile      |   1 +
 drivers/iio/pressure/mprls0025pa.c | 450 +++++++++++++++++++++++++++++
 3 files changed, 464 insertions(+)
 create mode 100644 drivers/iio/pressure/mprls0025pa.c

diff --git a/drivers/iio/pressure/Kconfig b/drivers/iio/pressure/Kconfig
index c9453389e4f7..43aef35ce778 100644
--- a/drivers/iio/pressure/Kconfig
+++ b/drivers/iio/pressure/Kconfig
@@ -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
diff --git a/drivers/iio/pressure/Makefile b/drivers/iio/pressure/Makefile
index 083ae87ff48f..c90f77210e94 100644
--- a/drivers/iio/pressure/Makefile
+++ b/drivers/iio/pressure/Makefile
@@ -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
diff --git a/drivers/iio/pressure/mprls0025pa.c b/drivers/iio/pressure/mprls0025pa.c
new file mode 100644
index 000000000000..06f40e47c68e
--- /dev/null
+++ b/drivers/iio/pressure/mprls0025pa.c
@@ -0,0 +1,450 @@
+// 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
+ *
+ * 7-bit I2C default slave address: 0x18
+ */
+
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/i2c.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/iio.h>
+#include <linux/iio/trigger_consumer.h>
+#include <linux/iio/triggered_buffer.h>
+
+#include <linux/regulator/consumer.h>
+
+#include <asm/unaligned.h>
+
+/* bits in i2c status byte */
+#define MPR_I2C_POWER	BIT(6)	/* device is powered */
+#define MPR_I2C_BUSY	BIT(5)	/* device is busy */
+#define MPR_I2C_MEMORY	BIT(2)	/* integrity test passed */
+#define MPR_I2C_MATH	BIT(0)	/* internal math saturation */
+
+/*
+ * 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
+ */
+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},
+};
+
+struct mpr_chan {
+	s32			pres;		/* pressure value */
+	s64			ts;		/* timestamp */
+};
+
+struct mpr_data {
+	struct i2c_client	*client;
+	struct mutex		lock;		/*
+						 * access to device during read
+						 */
+	u32			pmin;		/* minimal pressure in pascal */
+	u32			pmax;		/* maximal pressure in pascal */
+	enum mpr_func_id	function;	/* transfer function */
+	u32			outmin;		/*
+						 * minimal numerical range raw
+						 * value from sensor
+						 */
+	u32			outmax;		/*
+						 * maximal numerical range raw
+						 * value from sensor
+						 */
+	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;
+						 * used to distinguish between
+						 * irq mode and reading in a
+						 * loop until data is ready
+						 */
+	struct completion	completion;	/* handshake from irq to read */
+	struct mpr_chan		chan;		/*
+						 * channel values for buffered
+						 * mode
+						 */
+};
+
+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 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[4];
+
+	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,
+							(u32)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,
+							(u32)sizeof(buf));
+		return -EIO;
+	}
+
+	if (buf[0] & MPR_I2C_BUSY) {
+		/*
+		 * it should never be the case that status still indicates
+		 * business
+		 */
+		dev_err(dev, "data still not ready: %08x\n", buf[0]);
+		return -ETIMEDOUT;
+	}
+
+	*press = get_unaligned_be24(&buf[1]);
+
+	dev_dbg(dev, "received: %*ph cnt: %d\n", ret, buf, *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,
+};
+
+static int mpr_probe(struct i2c_client *client)
+{
+	int ret;
+	struct mpr_data *data;
+	struct iio_dev *indio_dev;
+	struct device *dev = &client->dev;
+	s64 scale, offset;
+
+	if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_READ_BYTE))
+		return dev_err_probe(dev, -EOPNOTSUPP,
+					"I2C functionality not supported\n");
+
+	indio_dev = devm_iio_device_alloc(dev, sizeof(*data));
+	if (!indio_dev)
+		return dev_err_probe(dev, -ENOMEM, "couldn't get iio_dev\n");
+
+	data = iio_priv(indio_dev);
+	data->client = client;
+	data->irq = client->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");
+
+	if (dev_fwnode(dev)) {
+		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");
+		ret = device_property_read_u32(dev,
+				"honeywell,transfer-function", &data->function);
+		if (ret)
+			return dev_err_probe(dev, ret,
+				"honeywell,transfer-function could not be read\n");
+		if (data->function > MPR_FUNCTION_C)
+			return dev_err_probe(dev, -EINVAL,
+				"honeywell,transfer-function %d invalid\n",
+								data->function);
+	} else {
+		/* when loaded as i2c device we need to use default values */
+		dev_notice(dev, "firmware node not found; using defaults\n");
+		data->pmin = 0;
+		data->pmax = 172369; /* 25 psi */
+		data->function = MPR_FUNCTION_A;
+	}
+
+	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, 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;
+}
+
+static const struct of_device_id mpr_matches[] = {
+	{ .compatible = "honeywell,mprls0025pa" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, mpr_matches);
+
+static const struct i2c_device_id mpr_id[] = {
+	{ "mprls0025pa" },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, mpr_id);
+
+static struct i2c_driver mpr_driver = {
+	.probe_new	= mpr_probe,
+	.id_table	= mpr_id,
+	.driver		= {
+		.name		= "mprls0025pa",
+		.of_match_table = mpr_matches,
+	},
+};
+module_i2c_driver(mpr_driver);
+
+MODULE_AUTHOR("Andreas Klinger <ak@it-klinger.de>");
+MODULE_DESCRIPTION("Honeywell MPRLS0025PA I2C driver");
+MODULE_LICENSE("GPL");
-- 
2.30.2

Re: [PATCH v5 2/3] iio: pressure: Honeywell mprls0025pa pressure sensor

[andy.shevchenko]

Tue, May 16, 2023 at 01:32:45PM +0200, Andreas Klinger kirjoitti:
> Honeywell mprls0025pa is a series of pressure sensors.
> 
> Add initial I2C support.
> 
> Note:
> - IIO buffered mode is supported
> - SPI mode is not supported

...

> + * Data sheet:

Datasheet

> + *  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

Is it URL? Can we have it clickable, i.e. unwrapped?

...

Missing bits.h

> +#include <linux/delay.h>
> +#include <linux/device.h>
> +#include <linux/i2c.h>
> +#include <linux/math64.h>
> +#include <linux/mod_devicetable.h>
> +#include <linux/module.h>
> +#include <linux/property.h>
> +#include <linux/units.h>

...

> +/*
> + * support _RAW sysfs interface:

Support

> + *
> + * 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
> + */

Kernel doc?

> +enum mpr_func_id {
> +	MPR_FUNCTION_A,
> +	MPR_FUNCTION_B,
> +	MPR_FUNCTION_C,
> +};

...

> +struct mpr_func_spec {
> +	u32			output_min;
> +	u32			output_max;
> +};

Can the linear_range.h be used for this?

...

> +struct mpr_data {
> +	struct i2c_client	*client;
> +	struct mutex		lock;		/*
> +						 * access to device during read
> +						 */
> +	u32			pmin;		/* minimal pressure in pascal */
> +	u32			pmax;		/* maximal pressure in pascal */
> +	enum mpr_func_id	function;	/* transfer function */
> +	u32			outmin;		/*
> +						 * minimal numerical range raw
> +						 * value from sensor
> +						 */
> +	u32			outmax;		/*
> +						 * maximal numerical range raw
> +						 * value from sensor
> +						 */
> +	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;
> +						 * used to distinguish between
> +						 * irq mode and reading in a
> +						 * loop until data is ready
> +						 */
> +	struct completion	completion;	/* handshake from irq to read */
> +	struct mpr_chan		chan;		/*
> +						 * channel values for buffered
> +						 * mode
> +						 */

Why not kernel doc?

> +};

...

> +static void mpr_reset(struct mpr_data *data)
> +{
> +	if (data->gpiod_reset) {

Actually this dups gpiod_*() checks, so only needed by udelay(). 

> +		gpiod_set_value(data->gpiod_reset, 0);
> +		udelay(10);
> +		gpiod_set_value(data->gpiod_reset, 1);

Why not sleeping for all of them?

> +	}
> +}

...

> +	if (ret != sizeof(wdata)) {
> +		dev_err(dev, "received size doesn't fit - ret: %d / %u\n", ret,
> +							(u32)sizeof(wdata));

Casting? Use proper specifier, i.e. %zu.

> +		return -EIO;
> +	}

...

> +		/* wait until status indicates data is ready */
> +		for (i = 0; i < nloops; i++) {
> +			/*
> +			 * datasheet only says to wait at least 5 ms for the

Datasheet

> +			 * 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;
> +		}

iopoll.h provides a macro for this. Reduces codebase a lot in this case.

> +	}

...

> +		dev_err(dev, "received size doesn't fit - ret: %d / %u\n", ret,
> +							(u32)sizeof(buf));

Use proper specifier.

...

> +	if (buf[0] & MPR_I2C_BUSY) {
> +		/*
> +		 * it should never be the case that status still indicates
> +		 * business
> +		 */
> +		dev_err(dev, "data still not ready: %08x\n", buf[0]);

Why 8? Is the buffer is of 32-bit values?

> +		return -ETIMEDOUT;
> +	}

...

> +err:

err_unlock:

> +	mutex_unlock(&data->lock);
> +	iio_trigger_notify_done(indio_dev->trig);
> +
> +	return IRQ_HANDLED;

...

> +	indio_dev = devm_iio_device_alloc(dev, sizeof(*data));
> +	if (!indio_dev)
> +		return dev_err_probe(dev, -ENOMEM, "couldn't get iio_dev\n");

-ENOMEM shouldn't be without error message, we will get one in that case.

...

> +	if (dev_fwnode(dev)) {

Why not simply use defaults?

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

-ERANGE ?

> +				"honeywell,transfer-function %d invalid\n",
> +								data->function);
> +	} else {
> +		/* when loaded as i2c device we need to use default values */
> +		dev_notice(dev, "firmware node not found; using defaults\n");
> +		data->pmin = 0;
> +		data->pmax = 172369; /* 25 psi */
> +		data->function = MPR_FUNCTION_A;
> +	}

...

> +	/*
> +	 * multiply with NANO before dividing by scale and later divide by NANO

Multiply

> +	 * again.
> +	 */

...

> +	if (ret)
> +		return dev_err_probe(dev, ret,
> +					"iio triggered buffer setup failed\n");

One line?

...

> +	if (ret)
> +		return dev_err_probe(dev, ret,
> +					"unable to register iio device\n");

Ditto.

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH v5 2/3] iio: pressure: Honeywell mprls0025pa pressure sensor

[Jonathan Cameron]

> 
> > +	if (dev_fwnode(dev)) {  
> 
> Why not simply use defaults?

Potential for inconsistent set if a firmware provides some but not others?
(at least that was my assumption that could well be wrong)

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

[PATCH v5 3/3] MAINTAINERS: Add Honeywell mprls0025pa sensor

[Andreas Klinger]

Add myself as a maintainer for Honeywell mprls0025pa sensor.

Signed-off-by: Andreas Klinger <ak@it-klinger.de>
---
 MAINTAINERS | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/MAINTAINERS b/MAINTAINERS
index c6545eb54104..7b68ec3fba88 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -9361,6 +9361,13 @@ F:	lib/test_hmm*
 F:	mm/hmm*
 F:	tools/testing/selftests/mm/*hmm*
 
+HONEYWELL MPRLS0025PA PRESSURE SENSOR SERIES IIO DRIVER
+M:	Andreas Klinger <ak@it-klinger.de>
+L:	linux-iio@vger.kernel.org
+S:	Maintained
+F:	Documentation/devicetree/bindings/iio/pressure/honeywell,mprls0025pa.yaml
+F:	drivers/iio/pressure/mprls0025pa.c
+
 HOST AP DRIVER
 M:	Jouni Malinen <j@w1.fi>
 L:	linux-wireless@vger.kernel.org
-- 
2.30.2

Re: [PATCH v5 0/3] Support Honeywell mprls0025pa pressure sensor

[Jonathan Cameron]

On Tue, 16 May 2023 13:30:44 +0200
Andreas Klinger <ak@it-klinger.de> wrote:

> Support Honeywell mprls0025pa pressure sensor.
Series applied to the togreg branch of iio.git and initially pushed out
as testing for 0-day to see if it can find anything we missed.

Thanks,

Jonathan

> 
> This patch series adds support for Honeywell mprls0025pa pressure sensor series.
> There are a variety of sensors with different pressure ranges supported.
> 
> Changes in v5:
> - Patch 1: "dt-bindings: iio: pressure: Support Honeywell mprls0025pa sensor"
>   - add Reviewd-by tag
>   - preserve formating in description
> - Patch 2: "iio: pressure: Honeywell mprls0025pa pressure sensor"
>   - make use of div_s64_rem()
>   - document calculation
>   - reorder includes
>   - use NANO from units.h
> - Patch 3: "MAINTAINERS: Add Honeywell mprls0025pa sensor"
>   - no changes
> 
> Changes in v4:
> - Patch 1: "dt-bindings: iio: pressure: Support Honeywell mprls0025pa sensor"
>   - change line length to 80 characters
>   - make vdd-supply mandatory
> - Patch 2: "iio: pressure: Honeywell mprls0025pa pressure sensor"
>   - change line length to 80 characters
>   - change regulator vcc to devm_regulator_get_enable()
>   - switch to probe_new
>   - many changes from the review
> - Patch 3: "MAINTAINERS: Add Honeywell mprls0025pa sensor"
>   - no changes
> 
> Changes in v3:
> - Patch 1: "dt-bindings: iio: pressure: Support Honeywell mprls0025pa sensor"
>   - fix errors while doing dt_binding_check
>   - add vdd-supply
> - Patch 2: "iio: pressure: Honeywell mpr pressure sensor"
>   - change to _RAW interface
>   - add transfer function
>   - add regulator
>   - move to device_property_xxx functions
>   - many more changes from the feedbacks
> - Patch 3: "MAINTAINERS: Add Honeywell mpr sensor"
>   - change file names
> 
> Changes in v2:
> - Patch 1: "dt-bindings: iio: pressure: Support Honeywell mprls0025pa sensor"
>   - change the global sensor decription of mpr to the specific sensor
>     mprls0025pa
>   - change compatible string
>   - rename the file to honeywell,mprls0025pa.yaml
>   - honeywell,pmin-pascal and honeywell,pmax-pascal: add unit pascal to property
>     names 
>   - add new property honeywell,transfer-function
> - Patch 2: "iio: pressure: Honeywell mpr pressure sensor"
>   - no change so far
>   - will be changed and send out as new version when the dt definition is
>     settled down
> - Patch 3: "MAINTAINERS: Add Honeywell mpr sensor"
>   - no change so far
> 
> Andreas Klinger (3):
>   dt-bindings: iio: pressure: Support Honeywell mprls0025pa sensor
>   iio: pressure: Honeywell mprls0025pa pressure sensor
>   MAINTAINERS: Add Honeywell mprls0025pa sensor
> 
>  .../iio/pressure/honeywell,mprls0025pa.yaml   | 104 ++++
>  MAINTAINERS                                   |   7 +
>  drivers/iio/pressure/Kconfig                  |  13 +
>  drivers/iio/pressure/Makefile                 |   1 +
>  drivers/iio/pressure/mprls0025pa.c            | 450 ++++++++++++++++++
>  5 files changed, 575 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/iio/pressure/honeywell,mprls0025pa.yaml
>  create mode 100644 drivers/iio/pressure/mprls0025pa.c
> 
> 
> base-commit: 457391b0380335d5e9a5babdec90ac53928b23b4

Re: [PATCH v5 0/3] Support Honeywell mprls0025pa pressure sensor

[andy.shevchenko]

Sat, May 20, 2023 at 05:24:05PM +0100, Jonathan Cameron kirjoitti:
> On Tue, 16 May 2023 13:30:44 +0200
> Andreas Klinger <ak@it-klinger.de> wrote:
> 
> > Support Honeywell mprls0025pa pressure sensor.
> Series applied to the togreg branch of iio.git and initially pushed out
> as testing for 0-day to see if it can find anything we missed.

Hmm... Should the comments I'm about to leave be addressed as followups?

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH v5 0/3] Support Honeywell mprls0025pa pressure sensor

[Jonathan Cameron]

On Mon, 29 May 2023 01:09:19 +0300
andy.shevchenko@gmail.com wrote:

> Sat, May 20, 2023 at 05:24:05PM +0100, Jonathan Cameron kirjoitti:
> > On Tue, 16 May 2023 13:30:44 +0200
> > Andreas Klinger <ak@it-klinger.de> wrote:
> >   
> > > Support Honeywell mprls0025pa pressure sensor.  
> > Series applied to the togreg branch of iio.git and initially pushed out
> > as testing for 0-day to see if it can find anything we missed.  
> 
> Hmm... Should the comments I'm about to leave be addressed as followups?
> 

Yes please.  As with previous, whilst good comments, nothing significant
enough that I'd want to rebase the tree.
Perhaps filter out the least important ones (one line vs two line on 81 char
lines) though.

Jonathan