1 // SPDX-License-Identifier: GPL-2.0
3  * Sensirion SCD30 carbon dioxide sensor serial driver
55 static int scd30_serdev_xfer(struct scd30_state *state, char *txbuf, int txsize,  in scd30_serdev_xfer()  argument
58 	struct serdev_device *serdev = to_serdev_device(state->dev);  in scd30_serdev_xfer()
59 	struct scd30_serdev_priv *priv = state->priv;  in scd30_serdev_xfer()
62 	priv->buf = rxbuf;  in scd30_serdev_xfer()
63 	priv->num_expected = rxsize;  in scd30_serdev_xfer()
64 	priv->num = 0;  in scd30_serdev_xfer()
70 		return -EIO;  in scd30_serdev_xfer()
72 	ret = wait_for_completion_interruptible_timeout(&priv->meas_ready, SCD30_SERDEV_TIMEOUT);  in scd30_serdev_xfer()
76 		return -ETIMEDOUT;  in scd30_serdev_xfer()
81 static int scd30_serdev_command(struct scd30_state *state, enum scd30_cmd cmd, u16 arg,  in scd30_serdev_command()  argument
85 	 * Communication over serial line is based on modbus protocol (or rather  in scd30_serdev_command()
86 	 * its variation called modbus over serial to be precise). Upon  in scd30_serdev_command()
92 	 * +------+------+-----+-----+-------+-------+-----+-----+  in scd30_serdev_command()
95 	 * +------+------+-----+-----+-------+-------+-----+-----+  in scd30_serdev_command()
103 	 * +------+------+--------+-------+-----+-------+-----+-----+  in scd30_serdev_command()
106 	 * +------+------+--------+-------+-----+-------+-----+-----+  in scd30_serdev_command()
142 	ret = scd30_serdev_xfer(state, txbuf, txsize, rxbuf, rxsize);  in scd30_serdev_command()
149 			dev_err(state->dev, "wrong message received\n");  in scd30_serdev_command()
150 			return -EIO;  in scd30_serdev_command()
154 		if (rxbuf[2] != (rxsize - SCD30_SERDEV_RX_HEADER_SIZE - SCD30_SERDEV_CRC_SIZE)) {  in scd30_serdev_command()
155 			dev_err(state->dev, "received data size does not match header\n");  in scd30_serdev_command()
156 			return -EIO;  in scd30_serdev_command()
159 		rxsize -= SCD30_SERDEV_CRC_SIZE;  in scd30_serdev_command()
162 			dev_err(state->dev, "data integrity check failed\n");  in scd30_serdev_command()
163 			return -EIO;  in scd30_serdev_command()
166 		rxsize -= SCD30_SERDEV_RX_HEADER_SIZE;  in scd30_serdev_command()
170 		dev_err(state->dev, "received unknown op code\n");  in scd30_serdev_command()
171 		return -EIO;  in scd30_serdev_command()
182 	struct scd30_state *state;  in scd30_serdev_receive_buf()  local
188 	state = iio_priv(indio_dev);  in scd30_serdev_receive_buf()
189 	priv = state->priv;  in scd30_serdev_receive_buf()
192 	if (!priv->buf)  in scd30_serdev_receive_buf()
195 	if (priv->num + size >= priv->num_expected)  in scd30_serdev_receive_buf()
196 		num = priv->num_expected - priv->num;  in scd30_serdev_receive_buf()
200 	memcpy(priv->buf + priv->num, buf, num);  in scd30_serdev_receive_buf()
201 	priv->num += num;  in scd30_serdev_receive_buf()
203 	if (priv->num == priv->num_expected) {  in scd30_serdev_receive_buf()
204 		priv->buf = NULL;  in scd30_serdev_receive_buf()
205 		complete(&priv->meas_ready);  in scd30_serdev_receive_buf()
218 	struct device *dev = &serdev->dev;  in scd30_serdev_probe()
224 		return -ENOMEM;  in scd30_serdev_probe()
226 	init_completion(&priv->meas_ready);  in scd30_serdev_probe()
262 MODULE_DESCRIPTION("Sensirion SCD30 carbon dioxide sensor serial driver");