iio: pressure: Add driver for DLH pressure sensors

All Sensors DLH is series of low voltage digital pressure sensors.
Additionally to pressure value sensors deliver a temperature value.
Sensors can be accessed over I2C and SPI, this driver supports
only I2C access.
Signed-off-by: Tomislav Denis <tomislav.denis@avl.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

MAINTAINERS

@@ -668,6 +668,13 @@ S:	Maintained
 F:	Documentation/i2c/busses/i2c-ali1563.rst
 F:	drivers/i2c/busses/i2c-ali1563.c
 
+ALL SENSORS DLH SERIES PRESSURE SENSORS DRIVER
+M:	Tomislav Denis <tomislav.denis@avl.com>
+W:	http://www.allsensors.com/
+S:	Maintained
+L:	linux-iio@vger.kernel.org
+F:	drivers/iio/pressure/dlhl60d.c
+
 ALLEGRO DVT VIDEO IP CORE DRIVER
 M:	Michael Tretter <m.tretter@pengutronix.de>
 R:	Pengutronix Kernel Team <kernel@pengutronix.de>

drivers/iio/pressure/Kconfig

@@ -53,6 +53,18 @@ config IIO_CROS_EC_BARO
 	  To compile this driver as a module, choose M here: the module
 	  will be called cros_ec_baro.
 
+config DLHL60D
+	tristate "All Sensors DLHL60D and DLHL60G low voltage digital pressure sensors"
+	depends on I2C
+	select IIO_BUFFER
+	select IIO_TRIGGERED_BUFFER
+	help
+	  Say yes here to build support for the All Sensors DLH series
+	  pressure sensors driver.
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called dlhl60d.
+
 config DPS310
 	tristate "Infineon DPS310 pressure and temperature sensor"
 	depends on I2C

drivers/iio/pressure/Makefile

@@ -9,6 +9,7 @@ obj-$(CONFIG_BMP280) += bmp280.o
 bmp280-objs := bmp280-core.o bmp280-regmap.o
 obj-$(CONFIG_BMP280_I2C) += bmp280-i2c.o
 obj-$(CONFIG_BMP280_SPI) += bmp280-spi.o
+obj-$(CONFIG_DLHL60D) += dlhl60d.o
 obj-$(CONFIG_DPS310) += dps310.o
 obj-$(CONFIG_IIO_CROS_EC_BARO) += cros_ec_baro.o
 obj-$(CONFIG_HID_SENSOR_PRESS)   += hid-sensor-press.o

drivers/iio/pressure/dlhl60d.c

+// SPDX-License-Identifier: GPL-2.0
+/*
+ * All Sensors DLH series low voltage digital pressure sensors
+ *
+ * Copyright (c) 2019 AVL DiTEST GmbH
+ *   Tomislav Denis <tomislav.denis@avl.com>
+ *
+ * Datasheet: http://www.allsensors.com/cad/DS-0355_Rev_B.PDF
+ */
+
+#include <linux/module.h>
+#include <linux/delay.h>
+#include <linux/i2c.h>
+#include <linux/iio/iio.h>
+#include <linux/iio/buffer.h>
+#include <linux/iio/trigger_consumer.h>
+#include <linux/iio/triggered_buffer.h>
+#include <asm/unaligned.h>
+
+/* Commands */
+#define DLH_START_SINGLE    0xAA
+
+/* Status bits */
+#define DLH_STATUS_OK       0x40
+
+/* DLH  data format */
+#define DLH_NUM_READ_BYTES  7
+#define DLH_NUM_DATA_BYTES  3
+#define DLH_NUM_PR_BITS     24
+#define DLH_NUM_TEMP_BITS   24
+
+/* DLH  timings */
+#define DLH_SINGLE_DUT_MS   5
+
+enum dhl_ids {
+	dlhl60d,
+	dlhl60g,
+};
+
+struct dlh_info {
+	u8 osdig;           /* digital offset factor */
+	unsigned int fss;   /* full scale span (inch H2O) */
+};
+
+struct dlh_state {
+	struct i2c_client *client;
+	struct dlh_info info;
+	bool use_interrupt;
+	struct completion completion;
+	u8 rx_buf[DLH_NUM_READ_BYTES] ____cacheline_aligned;
+};
+
+static struct dlh_info dlh_info_tbl[] = {
+	[dlhl60d] = {
+		.osdig = 2,
+		.fss = 120,
+	},
+	[dlhl60g] = {
+		.osdig = 10,
+		.fss = 60,
+	},
+};
+
+
+static int dlh_cmd_start_single(struct dlh_state *st)
+{
+	int ret;
+
+	ret = i2c_smbus_write_byte(st->client, DLH_START_SINGLE);
+	if (ret)
+		dev_err(&st->client->dev,
+			"%s: I2C write byte failed\n", __func__);
+
+	return ret;
+}
+
+static int dlh_cmd_read_data(struct dlh_state *st)
+{
+	int ret;
+
+	ret = i2c_master_recv(st->client, st->rx_buf, DLH_NUM_READ_BYTES);
+	if (ret < 0) {
+		dev_err(&st->client->dev,
+			"%s: I2C read block failed\n", __func__);
+		return ret;
+	}
+
+	if (st->rx_buf[0] != DLH_STATUS_OK) {
+		dev_err(&st->client->dev,
+			"%s: invalid status 0x%02x\n", __func__, st->rx_buf[0]);
+		return -EBUSY;
+	}
+
+	return 0;
+}
+
+static int dlh_start_capture_and_read(struct dlh_state *st)
+{
+	int ret;
+
+	if (st->use_interrupt)
+		reinit_completion(&st->completion);
+
+	ret = dlh_cmd_start_single(st);
+	if (ret)
+		return ret;
+
+	if (st->use_interrupt) {
+		ret = wait_for_completion_timeout(&st->completion,
+			msecs_to_jiffies(DLH_SINGLE_DUT_MS));
+		if (!ret) {
+			dev_err(&st->client->dev,
+				"%s: conversion timed out\n", __func__);
+			return -ETIMEDOUT;
+		}
+	} else {
+		mdelay(DLH_SINGLE_DUT_MS);
+	}
+
+	return dlh_cmd_read_data(st);
+}
+
+static int dlh_read_direct(struct dlh_state *st,
+	unsigned int *pressure, unsigned int *temperature)
+{
+	int ret;
+
+	ret = dlh_start_capture_and_read(st);
+	if (ret)
+		return ret;
+
+	*pressure = get_unaligned_be32(&st->rx_buf[1]) >> 8;
+	*temperature = get_unaligned_be32(&st->rx_buf[3]) &
+		GENMASK(DLH_NUM_TEMP_BITS - 1, 0);
+
+	return 0;
+}
+
+static int dlh_read_raw(struct iio_dev *indio_dev,
+	struct iio_chan_spec const *channel, int *value,
+	int *value2, long mask)
+{
+	struct dlh_state *st = iio_priv(indio_dev);
+	unsigned int pressure, temperature;
+	int ret;
+	s64 tmp;
+	s32 rem;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		ret = iio_device_claim_direct_mode(indio_dev);
+		if (ret)
+			return ret;
+
+		ret = dlh_read_direct(st, &pressure, &temperature);
+		iio_device_release_direct_mode(indio_dev);
+		if (ret)
+			return ret;
+
+		switch (channel->type) {
+		case IIO_PRESSURE:
+			*value = pressure;
+			return IIO_VAL_INT;
+
+		case IIO_TEMP:
+			*value = temperature;
+			return IIO_VAL_INT;
+
+		default:
+			return -EINVAL;
+		}
+	case IIO_CHAN_INFO_SCALE:
+		switch (channel->type) {
+		case IIO_PRESSURE:
+			tmp = div_s64(125LL * st->info.fss * 24909 * 100,
+				1 << DLH_NUM_PR_BITS);
+			tmp = div_s64_rem(tmp, 1000000000LL, &rem);
+			*value = tmp;
+			*value2 = rem;
+			return IIO_VAL_INT_PLUS_NANO;
+
+		case IIO_TEMP:
+			*value = 125 * 1000;
+			*value2 = DLH_NUM_TEMP_BITS;
+			return IIO_VAL_FRACTIONAL_LOG2;
+
+		default:
+			return -EINVAL;
+		}
+	case IIO_CHAN_INFO_OFFSET:
+		switch (channel->type) {
+		case IIO_PRESSURE:
+			*value = -125 * st->info.fss * 24909;
+			*value2 = 100 * st->info.osdig * 100000;
+			return IIO_VAL_FRACTIONAL;
+
+		case IIO_TEMP:
+			*value = -40 * 1000;
+			return IIO_VAL_INT;
+
+		default:
+			return -EINVAL;
+		}
+	}
+
+	return -EINVAL;
+}
+
+static const struct iio_info dlh_info = {
+	.read_raw = dlh_read_raw,
+};
+
+static const struct iio_chan_spec dlh_channels[] = {
+	{
+		.type = IIO_PRESSURE,
+		.indexed = 1,
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
+		.info_mask_shared_by_type =
+			BIT(IIO_CHAN_INFO_SCALE) |
+			BIT(IIO_CHAN_INFO_OFFSET),
+		.scan_index = 0,
+		.scan_type = {
+			.sign = 'u',
+			.realbits = DLH_NUM_PR_BITS,
+			.storagebits = 32,
+			.shift = 8,
+			.endianness = IIO_BE,
+		},
+	}, {
+		.type = IIO_TEMP,
+		.indexed = 1,
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
+		.info_mask_shared_by_type =
+			BIT(IIO_CHAN_INFO_SCALE) |
+			BIT(IIO_CHAN_INFO_OFFSET),
+		.scan_index = 1,
+		.scan_type = {
+			.sign = 'u',
+			.realbits = DLH_NUM_TEMP_BITS,
+			.storagebits = 32,
+			.shift = 8,
+			.endianness = IIO_BE,
+		},
+	}
+};
+
+static irqreturn_t dlh_trigger_handler(int irq, void *private)
+{
+	struct iio_poll_func *pf = private;
+	struct iio_dev *indio_dev = pf->indio_dev;
+	struct dlh_state *st = iio_priv(indio_dev);
+	int ret;
+	unsigned int chn, i = 0;
+	__be32 tmp_buf[2];
+
+	ret = dlh_start_capture_and_read(st);
+	if (ret)
+		goto out;
+
+	for_each_set_bit(chn, indio_dev->active_scan_mask,
+		indio_dev->masklength) {
+		memcpy(tmp_buf + i,
+			&st->rx_buf[1] + chn * DLH_NUM_DATA_BYTES,
+			DLH_NUM_DATA_BYTES);
+		i++;
+	}
+
+	iio_push_to_buffers(indio_dev, tmp_buf);
+
+out:
+	iio_trigger_notify_done(indio_dev->trig);
+
+	return IRQ_HANDLED;
+}
+
+static irqreturn_t dlh_interrupt(int irq, void *private)
+{
+	struct iio_dev *indio_dev = private;
+	struct dlh_state *st = iio_priv(indio_dev);
+
+	complete(&st->completion);
+
+	return IRQ_HANDLED;
+};
+
+static int dlh_probe(struct i2c_client *client,
+	const struct i2c_device_id *id)
+{
+	struct dlh_state *st;
+	struct iio_dev *indio_dev;
+	int ret;
+
+	if (!i2c_check_functionality(client->adapter,
+		I2C_FUNC_I2C | I2C_FUNC_SMBUS_WRITE_BYTE)) {
+		dev_err(&client->dev,
+			"adapter doesn't support required i2c functionality\n");
+		return -EOPNOTSUPP;
+	}
+
+	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*st));
+	if (!indio_dev) {
+		dev_err(&client->dev, "failed to allocate iio device\n");
+		return -ENOMEM;
+	}
+
+	i2c_set_clientdata(client, indio_dev);
+
+	st = iio_priv(indio_dev);
+	st->info = dlh_info_tbl[id->driver_data];
+	st->client = client;
+	st->use_interrupt = false;
+
+	indio_dev->name = id->name;
+	indio_dev->dev.parent = &client->dev;
+	indio_dev->dev.of_node = client->dev.of_node;
+	indio_dev->info = &dlh_info;
+	indio_dev->modes = INDIO_DIRECT_MODE;
+	indio_dev->channels =  dlh_channels;
+	indio_dev->num_channels = ARRAY_SIZE(dlh_channels);
+
+	if (client->irq > 0) {
+		ret = devm_request_threaded_irq(&client->dev, client->irq,
+			dlh_interrupt, NULL,
+			IRQF_TRIGGER_RISING | IRQF_ONESHOT,
+			id->name, indio_dev);
+		if (ret) {
+			dev_err(&client->dev, "failed to allocate threaded irq");
+			return ret;
+		}
+
+		st->use_interrupt = true;
+		init_completion(&st->completion);
+	}
+
+	ret = devm_iio_triggered_buffer_setup(&client->dev, indio_dev,
+		NULL, &dlh_trigger_handler, NULL);
+	if (ret) {
+		dev_err(&client->dev, "failed to setup iio buffer\n");
+		return ret;
+	}
+
+	ret = devm_iio_device_register(&client->dev, indio_dev);
+	if (ret)
+		dev_err(&client->dev, "failed to register iio device\n");
+
+	return ret;
+}
+
+static const struct of_device_id dlh_of_match[] = {
+	{ .compatible = "asc,dlhl60d" },
+	{ .compatible = "asc,dlhl60g" },
+	{}
+};
+MODULE_DEVICE_TABLE(of, dlh_of_match);
+
+static const struct i2c_device_id dlh_id[] = {
+	{ "dlhl60d",    dlhl60d },
+	{ "dlhl60g",    dlhl60g },
+	{}
+};
+MODULE_DEVICE_TABLE(i2c, dlh_id);
+
+static struct i2c_driver dlh_driver = {
+	.driver = {
+		.name = "dlhl60d",
+		.of_match_table = dlh_of_match,
+	},
+	.probe = dlh_probe,
+	.id_table = dlh_id,
+};
+module_i2c_driver(dlh_driver);
+
+MODULE_AUTHOR("Tomislav Denis <tomislav.denis@avl.com>");
+MODULE_DESCRIPTION("Driver for All Sensors DLH series pressure sensors");
+MODULE_LICENSE("GPL v2");