--- /dev/null
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Plantower PMS7003 particulate matter sensor driver
+ *
+ * Copyright (c) Tomasz Duszynski <tduszyns@gmail.com>
+ */
+
+#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 0x424d
+/* 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 pms7003_cmd {
+ CMD_WAKEUP,
+ CMD_ENTER_PASSIVE_MODE,
+ CMD_READ_PASSIVE,
+ CMD_SLEEP,
+};
+
+/*
+ * commands have following format:
+ *
+ * +------+------+-----+------+-----+-----------+-----------+
+ * | 0x42 | 0x4d | cmd | 0x00 | arg | cksum msb | cksum lsb |
+ * +------+------+-----+------+-----+-----------+-----------+
+ */
+static const u8 pms7003_cmd_tbl[][PMS7003_CMD_LENGTH] = {
+ [CMD_WAKEUP] = { 0x42, 0x4d, 0xe4, 0x00, 0x01, 0x01, 0x74 },
+ [CMD_ENTER_PASSIVE_MODE] = { 0x42, 0x4d, 0xe1, 0x00, 0x00, 0x01, 0x70 },
+ [CMD_READ_PASSIVE] = { 0x42, 0x4d, 0xe2, 0x00, 0x00, 0x01, 0x71 },
+ [CMD_SLEEP] = { 0x42, 0x4d, 0xe4, 0x00, 0x00, 0x01, 0x73 },
+};
+
+struct pms7003_frame {
+ u8 data[PMS7003_MAX_DATA_LENGTH];
+ u16 expected_length;
+ u16 length;
+};
+
+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 int pms7003_do_cmd(struct pms7003_state *state, enum pms7003_cmd cmd)
+{
+ int ret;
+
+ ret = serdev_device_write(state->serdev, pms7003_cmd_tbl[cmd],
+ PMS7003_CMD_LENGTH, PMS7003_TIMEOUT);
+ if (ret < PMS7003_CMD_LENGTH)
+ return ret < 0 ? ret : -EIO;
+
+ 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(const u8 *data)
+{
+ return clamp_val(get_unaligned_be16(data),
+ 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->data + PMS7003_PM1_OFFSET);
+ data[PM2P5] = pms7003_get_pm(frame->data + PMS7003_PM2P5_OFFSET);
+ data[PM10] = pms7003_get_pm(frame->data + 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;
+ }
+
+ *val = pms7003_get_pm(frame->data + chan->address);
+ 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, _addr) { \
+ .type = IIO_MASSCONCENTRATION, \
+ .modified = 1, \
+ .channel2 = IIO_MOD_ ## _mod, \
+ .address = _addr, \
+ .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_PM1_OFFSET),
+ PMS7003_CHAN(1, PM2P5, PMS7003_PM2P5_OFFSET),
+ PMS7003_CHAN(2, PM10, PMS7003_PM10_OFFSET),
+ IIO_CHAN_SOFT_TIMESTAMP(3),
+};
+
+static u16 pms7003_calc_checksum(struct pms7003_frame *frame)
+{
+ u16 checksum = (PMS7003_MAGIC >> 8) + (u8)(PMS7003_MAGIC & 0xff) +
+ (frame->length >> 8) + (u8)frame->length;
+ int i;
+
+ for (i = 0; i < frame->length - PMS7003_CHECKSUM_LENGTH; i++)
+ checksum += frame->data[i];
+
+ return checksum;
+}
+
+static bool pms7003_frame_is_okay(struct pms7003_frame *frame)
+{
+ int offset = frame->length - PMS7003_CHECKSUM_LENGTH;
+ u16 checksum = get_unaligned_be16(frame->data + offset);
+
+ return checksum == pms7003_calc_checksum(frame);
+}
+
+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 num;
+
+ if (!frame->expected_length) {
+ u16 magic;
+
+ /* wait for SOF and data length */
+ if (size < 4)
+ return 0;
+
+ magic = get_unaligned_be16(buf);
+ if (magic != PMS7003_MAGIC)
+ return 2;
+
+ num = get_unaligned_be16(buf + 2);
+ if (num <= PMS7003_MAX_DATA_LENGTH) {
+ frame->expected_length = num;
+ frame->length = 0;
+ }
+
+ return 4;
+ }
+
+ num = min(size, (size_t)(frame->expected_length - frame->length));
+ memcpy(frame->data + frame->length, buf, num);
+ frame->length += num;
+
+ if (frame->length == frame->expected_length) {
+ if (pms7003_frame_is_okay(frame))
+ complete(&state->frame_ready);
+
+ frame->expected_length = 0;
+ }
+
+ return num;
+}
+
+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");
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