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From:   Tomasz Duszynski <tduszyns@gmail.com>
To:     linux-iio@vger.kernel.org
Cc:     linux-kernel@vger.kernel.org, devicetree@vger.kernel.org,
        Tomasz Duszynski <tduszyns@gmail.com>
Subject: [PATCH 1/3] iio: chemical: add support for Plantower PMS7003 sensor
Date:   Sun,  6 Jan 2019 18:16:12 +0100
Message-Id: <20190106171614.12615-2-tduszyns@gmail.com>
In-Reply-To: <20190106171614.12615-1-tduszyns@gmail.com>
References: <20190106171614.12615-1-tduszyns@gmail.com>
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Add support for Plantower PMS7003 particulate matter sensor.

Signed-off-by: Tomasz Duszynski <tduszyns@gmail.com>
---
 drivers/iio/chemical/Kconfig   |  10 +
 drivers/iio/chemical/Makefile  |   1 +
 drivers/iio/chemical/pms7003.c | 411 +++++++++++++++++++++++++++++++++
 3 files changed, 422 insertions(+)
 create mode 100644 drivers/iio/chemical/pms7003.c

diff --git a/drivers/iio/chemical/Kconfig b/drivers/iio/chemical/Kconfig
index 57832b4360e9..d5d146e9e372 100644
--- a/drivers/iio/chemical/Kconfig
+++ b/drivers/iio/chemical/Kconfig
@@ -61,6 +61,16 @@ config IAQCORE
 	  iAQ-Core Continuous/Pulsed VOC (Volatile Organic Compounds)
 	  sensors
 
+config PMS7003
+	tristate "Plantower PMS7003 particulate matter sensor"
+	depends on SERIAL_DEV_BUS
+	help
+	  Say Y here to build support for the Plantower PMS7003 particulate
+	  matter sensor.
+
+	  To compile this driver as a module, choose M here: the module will
+	  be called pms7003.
+
 config SPS30
 	tristate "SPS30 particulate matter sensor"
 	depends on I2C
diff --git a/drivers/iio/chemical/Makefile b/drivers/iio/chemical/Makefile
index 65bf0f89c0e4..f5d1365acb49 100644
--- a/drivers/iio/chemical/Makefile
+++ b/drivers/iio/chemical/Makefile
@@ -9,6 +9,7 @@ obj-$(CONFIG_BME680_I2C) += bme680_i2c.o
 obj-$(CONFIG_BME680_SPI) += bme680_spi.o
 obj-$(CONFIG_CCS811)		+= ccs811.o
 obj-$(CONFIG_IAQCORE)		+= ams-iaq-core.o
+obj-$(CONFIG_PMS7003) += pms7003.o
 obj-$(CONFIG_SENSIRION_SGP30)	+= sgp30.o
 obj-$(CONFIG_SPS30) += sps30.o
 obj-$(CONFIG_VZ89X)		+= vz89x.o
diff --git a/drivers/iio/chemical/pms7003.c b/drivers/iio/chemical/pms7003.c
new file mode 100644
index 000000000000..bc8a4fbdf641
--- /dev/null
+++ b/drivers/iio/chemical/pms7003.c
@@ -0,0 +1,411 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Plantower PMS7003 particulate matter sensor driver
+ *
+ * Copyright (c) Tomasz Duszynski <tduszyns@gmail.com>
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <asm/unaligned.h>
+#include <linux/completion.h>
+#include <linux/device.h>
+#include <linux/errno.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/jiffies.h>
+#include <linux/kernel.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/serdev.h>
+
+#define PMS7003_DRIVER_NAME "pms7003"
+
+#define PMS7003_MAGIC_MSB 0x42
+#define PMS7003_MAGIC_LSB 0x4d
+/* last 2 data bytes hold frame checksum */
+#define PMS7003_MAX_DATA_LENGTH 28
+#define PMS7003_CHECKSUM_LENGTH 2
+#define PMS7003_PM10_OFFSET 10
+#define PMS7003_PM2P5_OFFSET 8
+#define PMS7003_PM1_OFFSET 6
+
+#define PMS7003_TIMEOUT msecs_to_jiffies(6000)
+#define PMS7003_CMD_LENGTH 7
+#define PMS7003_PM_MAX 1000
+#define PMS7003_PM_MIN 0
+
+enum {
+	PM1,
+	PM2P5,
+	PM10,
+};
+
+enum {
+	CMD_WAKEUP,
+	CMD_ENTER_PASSIVE_MODE,
+	CMD_READ_PASSIVE,
+	CMD_SLEEP,
+};
+
+enum {
+	STATE_MAGIC_MSB,
+	STATE_MAGIC_LSB,
+	STATE_LENGTH_MSB,
+	STATE_LENGTH_LSB,
+	STATE_DATA,
+};
+
+struct pms7003_frame {
+	u8 data[PMS7003_MAX_DATA_LENGTH];
+	u16 expected_length;
+	u16 length;
+	int state;
+};
+
+struct pms7003_state {
+	struct serdev_device *serdev;
+	struct pms7003_frame frame;
+	struct completion frame_ready;
+	struct mutex lock; /* must be held whenever state gets touched */
+};
+
+static u16 pms7003_calc_checksum(const u8 *data, int size)
+{
+	u16 checksum = 0;
+
+	while (size--)
+		checksum += data[size];
+
+	return checksum;
+}
+
+static int pms7003_do_cmd(struct pms7003_state *state, u8 cmd)
+{
+	/*
+	 * commands have following format:
+	 *
+	 * +------+------+-----+------+-----+-----------+-----------+
+	 * | 0x42 | 0x4d | cmd | 0x00 | arg | cksum msb | cksum lsb |
+	 * +------+------+-----+------+-----+-----------+-----------+
+	 */
+	u8 tmp[PMS7003_CMD_LENGTH] = { PMS7003_MAGIC_MSB, PMS7003_MAGIC_LSB };
+	int ret, n = 2;
+	u16 checksum;
+
+	switch (cmd) {
+	case CMD_WAKEUP:
+		tmp[n++] = 0xe4;
+		tmp[n++] = 0x00;
+		tmp[n++] = 0x01;
+		break;
+	case CMD_ENTER_PASSIVE_MODE:
+		tmp[n++] = 0xe1;
+		tmp[n++] = 0x00;
+		tmp[n++] = 0x00;
+		break;
+	case CMD_READ_PASSIVE:
+		tmp[n++] = 0xe2;
+		tmp[n++] = 0x00;
+		tmp[n++] = 0x00;
+		break;
+	case CMD_SLEEP:
+		tmp[n++] = 0xe4;
+		tmp[n++] = 0x00;
+		tmp[n++] = 0x00;
+		break;
+	}
+
+	checksum = pms7003_calc_checksum(tmp, n);
+	put_unaligned_be16(checksum, tmp + n);
+	n += PMS7003_CHECKSUM_LENGTH;
+
+	ret = serdev_device_write(state->serdev, tmp, n, PMS7003_TIMEOUT);
+	if (ret)
+		return ret;
+
+	ret = wait_for_completion_interruptible_timeout(&state->frame_ready,
+							PMS7003_TIMEOUT);
+	if (!ret)
+		ret = -ETIMEDOUT;
+
+	return ret < 0 ? ret : 0;
+}
+
+static u16 pms7003_get_pm(struct pms7003_frame *frame, int offset)
+{
+	return clamp_val(get_unaligned_be16(frame->data + offset),
+			 PMS7003_PM_MIN, PMS7003_PM_MAX);
+}
+
+static irqreturn_t pms7003_trigger_handler(int irq, void *p)
+{
+	struct iio_poll_func *pf = p;
+	struct iio_dev *indio_dev = pf->indio_dev;
+	struct pms7003_state *state = iio_priv(indio_dev);
+	struct pms7003_frame *frame = &state->frame;
+	u16 data[3 + 1 + 4]; /* PM1, PM2P5, PM10, padding, timestamp */
+	int ret;
+
+	mutex_lock(&state->lock);
+	ret = pms7003_do_cmd(state, CMD_READ_PASSIVE);
+	if (ret) {
+		mutex_unlock(&state->lock);
+		goto err;
+	}
+
+	data[PM1] = pms7003_get_pm(frame, PMS7003_PM1_OFFSET);
+	data[PM2P5] = pms7003_get_pm(frame, PMS7003_PM2P5_OFFSET);
+	data[PM10] = pms7003_get_pm(frame, PMS7003_PM10_OFFSET);
+	mutex_unlock(&state->lock);
+
+	iio_push_to_buffers_with_timestamp(indio_dev, data,
+					   iio_get_time_ns(indio_dev));
+err:
+	iio_trigger_notify_done(indio_dev->trig);
+
+	return IRQ_HANDLED;
+}
+
+static int pms7003_read_raw(struct iio_dev *indio_dev,
+			    struct iio_chan_spec const *chan,
+			    int *val, int *val2, long mask)
+{
+	struct pms7003_state *state = iio_priv(indio_dev);
+	struct pms7003_frame *frame = &state->frame;
+	int ret;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_PROCESSED:
+		switch (chan->type) {
+		case IIO_MASSCONCENTRATION:
+			mutex_lock(&state->lock);
+			ret = pms7003_do_cmd(state, CMD_READ_PASSIVE);
+			if (ret) {
+				mutex_unlock(&state->lock);
+				return ret;
+			}
+
+			switch (chan->channel2) {
+			case IIO_MOD_PM1:
+				*val = pms7003_get_pm(frame,
+						      PMS7003_PM1_OFFSET);
+				break;
+			case IIO_MOD_PM2P5:
+				*val = pms7003_get_pm(frame,
+						      PMS7003_PM2P5_OFFSET);
+				break;
+			case IIO_MOD_PM10:
+				*val = pms7003_get_pm(frame,
+						      PMS7003_PM10_OFFSET);
+				break;
+			}
+			mutex_unlock(&state->lock);
+
+			return IIO_VAL_INT;
+		default:
+			return -EINVAL;
+		}
+	}
+
+	return -EINVAL;
+}
+
+
+static const struct iio_info pms7003_info = {
+	.read_raw = pms7003_read_raw,
+};
+
+#define PMS7003_CHAN(_index, _mod) { \
+	.type = IIO_MASSCONCENTRATION, \
+	.modified = 1, \
+	.channel2 = IIO_MOD_ ## _mod, \
+	.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED), \
+	.scan_index = _index, \
+	.scan_type = { \
+		.sign = 'u', \
+		.realbits = 10, \
+		.storagebits = 16, \
+		.endianness = IIO_CPU, \
+	}, \
+}
+
+static const struct iio_chan_spec pms7003_channels[] = {
+	PMS7003_CHAN(0, PM1),
+	PMS7003_CHAN(1, PM2P5),
+	PMS7003_CHAN(2, PM10),
+	IIO_CHAN_SOFT_TIMESTAMP(3),
+};
+
+static int pms7003_frame_okay(struct pms7003_frame *frame)
+{
+	int offset = frame->length - PMS7003_CHECKSUM_LENGTH;
+	u16 checksum = PMS7003_MAGIC_MSB + PMS7003_MAGIC_LSB +
+		       (frame->length >> 8) + (u8)frame->length +
+		       pms7003_calc_checksum(frame->data, offset);
+
+	return checksum == get_unaligned_be16(frame->data + offset);
+}
+
+static int pms7003_update_frame(struct pms7003_frame *frame, u8 byte)
+{
+	switch (frame->state) {
+	case STATE_MAGIC_MSB:
+		if (byte != PMS7003_MAGIC_MSB)
+			return 1;
+		frame->state = STATE_MAGIC_LSB;
+		frame->length = 0;
+		return 1;
+	case STATE_MAGIC_LSB:
+		if (byte != PMS7003_MAGIC_LSB) {
+			frame->state = STATE_MAGIC_MSB;
+			return 1;
+		}
+		frame->state = STATE_LENGTH_MSB;
+		return 1;
+	case STATE_LENGTH_MSB:
+		frame->expected_length = (u16)byte << 8;
+		frame->state = STATE_LENGTH_LSB;
+		return 1;
+	case STATE_LENGTH_LSB:
+		frame->expected_length |= byte;
+		frame->state = STATE_DATA;
+		return 1;
+	case STATE_DATA:
+		if (frame->length > PMS7003_MAX_DATA_LENGTH) {
+			frame->state = STATE_MAGIC_MSB;
+			return 1;
+		}
+
+		frame->data[frame->length++] = byte;
+
+		if (frame->length != frame->expected_length)
+			return 1;
+
+		if (!pms7003_frame_okay(frame)) {
+			frame->state = STATE_MAGIC_MSB;
+			return 1;
+		}
+
+		frame->state = STATE_MAGIC_MSB;
+		break;
+	}
+
+	return 0;
+}
+
+static int pms7003_receive_buf(struct serdev_device *serdev,
+			       const unsigned char *buf, size_t size)
+{
+	struct iio_dev *indio_dev = serdev_device_get_drvdata(serdev);
+	struct pms7003_state *state = iio_priv(indio_dev);
+	struct pms7003_frame *frame = &state->frame;
+	int i, ret;
+
+	for (i = 0; i < size; i++) {
+		ret = pms7003_update_frame(frame, buf[i]);
+		if (ret)
+			continue;
+
+		complete(&state->frame_ready);
+		return i + 1;
+	}
+
+	return size;
+}
+
+static const struct serdev_device_ops pms7003_serdev_ops = {
+	.receive_buf = pms7003_receive_buf,
+	.write_wakeup = serdev_device_write_wakeup,
+};
+
+static void pms7003_stop(void *data)
+{
+	struct pms7003_state *state = data;
+
+	pms7003_do_cmd(state, CMD_SLEEP);
+}
+
+static const unsigned long pms7003_scan_masks[] = { 0x07, 0x00 };
+
+static int pms7003_probe(struct serdev_device *serdev)
+{
+	struct pms7003_state *state;
+	struct iio_dev *indio_dev;
+	int ret;
+
+	indio_dev = devm_iio_device_alloc(&serdev->dev, sizeof(*state));
+	if (!indio_dev)
+		return -ENOMEM;
+
+	state = iio_priv(indio_dev);
+	serdev_device_set_drvdata(serdev, indio_dev);
+	state->serdev = serdev;
+	indio_dev->dev.parent = &serdev->dev;
+	indio_dev->info = &pms7003_info;
+	indio_dev->name = PMS7003_DRIVER_NAME;
+	indio_dev->channels = pms7003_channels,
+	indio_dev->num_channels = ARRAY_SIZE(pms7003_channels);
+	indio_dev->modes = INDIO_DIRECT_MODE;
+	indio_dev->available_scan_masks = pms7003_scan_masks;
+
+	mutex_init(&state->lock);
+	init_completion(&state->frame_ready);
+
+	serdev_device_set_client_ops(serdev, &pms7003_serdev_ops);
+	ret = devm_serdev_device_open(&serdev->dev, serdev);
+	if (ret)
+		return ret;
+
+	serdev_device_set_baudrate(serdev, 9600);
+	serdev_device_set_flow_control(serdev, false);
+
+	ret = serdev_device_set_parity(serdev, SERDEV_PARITY_NONE);
+	if (ret)
+		return ret;
+
+	ret = pms7003_do_cmd(state, CMD_WAKEUP);
+	if (ret) {
+		dev_err(&serdev->dev, "failed to wakeup sensor\n");
+		return ret;
+	}
+
+	ret = pms7003_do_cmd(state, CMD_ENTER_PASSIVE_MODE);
+	if (ret) {
+		dev_err(&serdev->dev, "failed to enter passive mode\n");
+		return ret;
+	}
+
+	ret = devm_add_action_or_reset(&serdev->dev, pms7003_stop, state);
+	if (ret)
+		return ret;
+
+	ret = devm_iio_triggered_buffer_setup(&serdev->dev, indio_dev, NULL,
+					      pms7003_trigger_handler, NULL);
+	if (ret)
+		return ret;
+
+	return devm_iio_device_register(&serdev->dev, indio_dev);
+}
+
+static const struct of_device_id pms7003_of_match[] = {
+	{ .compatible = "plantower,pms7003" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, pms7003_of_match);
+
+static struct serdev_device_driver pms7003_driver = {
+	.driver = {
+		.name = PMS7003_DRIVER_NAME,
+		.of_match_table = pms7003_of_match,
+	},
+	.probe = pms7003_probe,
+};
+module_serdev_device_driver(pms7003_driver);
+
+MODULE_AUTHOR("Tomasz Duszynski <tduszyns@gmail.com>");
+MODULE_DESCRIPTION("Plantower PMS7003 particulate matter sensor driver");
+MODULE_LICENSE("GPL v2");
-- 
2.20.1