2  * SPI slave handler reporting uptime at reception of previous SPI message
4  * This SPI slave handler sends the time of reception of the last SPI message
5  * as two 32-bit unsigned integers in binary format and in network byte order,
9  * Copyright (C) 2016-2017 Glider bvba
15  * Usage (assuming /dev/spidev2.0 corresponds to the SPI master on the remote
18  *   # spidev_test -D /dev/spidev2.0 -p dummy-8B
19  *   spi mode: 0x0
30 #include <linux/spi/spi.h>
34 	struct spi_device *spi;  member
48 	ret = priv->msg.status;  in spi_slave_time_complete()
59 	dev_info(&priv->spi->dev, "Terminating\n");  in spi_slave_time_complete()
60 	complete(&priv->finished);  in spi_slave_time_complete()
72 	priv->buf[0] = cpu_to_be32(ts);  in spi_slave_time_submit()
73 	priv->buf[1] = cpu_to_be32(rem_us);  in spi_slave_time_submit()
75 	spi_message_init_with_transfers(&priv->msg, &priv->xfer, 1);  in spi_slave_time_submit()
77 	priv->msg.complete = spi_slave_time_complete;  in spi_slave_time_submit()
78 	priv->msg.context = priv;  in spi_slave_time_submit()
80 	ret = spi_async(priv->spi, &priv->msg);  in spi_slave_time_submit()
82 		dev_err(&priv->spi->dev, "spi_async() failed %d\n", ret);  in spi_slave_time_submit()
87 static int spi_slave_time_probe(struct spi_device *spi)  in spi_slave_time_probe()  argument
92 	priv = devm_kzalloc(&spi->dev, sizeof(*priv), GFP_KERNEL);  in spi_slave_time_probe()
94 		return -ENOMEM;  in spi_slave_time_probe()
96 	priv->spi = spi;  in spi_slave_time_probe()
97 	init_completion(&priv->finished);  in spi_slave_time_probe()
98 	priv->xfer.tx_buf = priv->buf;  in spi_slave_time_probe()
99 	priv->xfer.len = sizeof(priv->buf);  in spi_slave_time_probe()
105 	spi_set_drvdata(spi, priv);  in spi_slave_time_probe()
109 static int spi_slave_time_remove(struct spi_device *spi)  in spi_slave_time_remove()  argument
111 	struct spi_slave_time_priv *priv = spi_get_drvdata(spi);  in spi_slave_time_remove()
113 	spi_slave_abort(spi);  in spi_slave_time_remove()
114 	wait_for_completion(&priv->finished);  in spi_slave_time_remove()
120 		.name	= "spi-slave-time",
128 MODULE_DESCRIPTION("SPI slave reporting uptime at previous SPI message");