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a0386bba70
The value returned by an spi driver's remove function is mostly ignored. (Only an error message is printed if the value is non-zero that the error is ignored.) So change the prototype of the remove function to return no value. This way driver authors are not tempted to assume that passing an error to the upper layer is a good idea. All drivers are adapted accordingly. There is no intended change of behaviour, all callbacks were prepared to return 0 before. Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Acked-by: Marc Kleine-Budde <mkl@pengutronix.de> Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be> Acked-by: Jérôme Pouiller <jerome.pouiller@silabs.com> Acked-by: Miquel Raynal <miquel.raynal@bootlin.com> Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Acked-by: Claudius Heine <ch@denx.de> Acked-by: Stefan Schmidt <stefan@datenfreihafen.org> Acked-by: Alexandre Belloni <alexandre.belloni@bootlin.com> Acked-by: Ulf Hansson <ulf.hansson@linaro.org> # For MMC Acked-by: Marcus Folkesson <marcus.folkesson@gmail.com> Acked-by: Łukasz Stelmach <l.stelmach@samsung.com> Acked-by: Lee Jones <lee.jones@linaro.org> Link: https://lore.kernel.org/r/20220123175201.34839-6-u.kleine-koenig@pengutronix.de Signed-off-by: Mark Brown <broonie@kernel.org>
128 lines
2.9 KiB
C
128 lines
2.9 KiB
C
/*
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* SPI slave handler reporting uptime at reception of previous SPI message
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*
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* This SPI slave handler sends the time of reception of the last SPI message
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* as two 32-bit unsigned integers in binary format and in network byte order,
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* representing the number of seconds and fractional seconds (in microseconds)
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* since boot up.
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*
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* Copyright (C) 2016-2017 Glider bvba
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*
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* This file is subject to the terms and conditions of the GNU General Public
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* License. See the file "COPYING" in the main directory of this archive
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* for more details.
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*
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* Usage (assuming /dev/spidev2.0 corresponds to the SPI master on the remote
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* system):
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*
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* # spidev_test -D /dev/spidev2.0 -p dummy-8B
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* spi mode: 0x0
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* bits per word: 8
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* max speed: 500000 Hz (500 KHz)
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* RX | 00 00 04 6D 00 09 5B BB ...
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* ^^^^^ ^^^^^^^^
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* seconds microseconds
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*/
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#include <linux/completion.h>
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#include <linux/module.h>
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#include <linux/sched/clock.h>
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#include <linux/spi/spi.h>
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struct spi_slave_time_priv {
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struct spi_device *spi;
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struct completion finished;
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struct spi_transfer xfer;
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struct spi_message msg;
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__be32 buf[2];
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};
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static int spi_slave_time_submit(struct spi_slave_time_priv *priv);
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static void spi_slave_time_complete(void *arg)
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{
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struct spi_slave_time_priv *priv = arg;
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int ret;
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ret = priv->msg.status;
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if (ret)
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goto terminate;
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ret = spi_slave_time_submit(priv);
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if (ret)
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goto terminate;
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return;
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terminate:
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dev_info(&priv->spi->dev, "Terminating\n");
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complete(&priv->finished);
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}
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static int spi_slave_time_submit(struct spi_slave_time_priv *priv)
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{
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u32 rem_us;
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int ret;
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u64 ts;
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ts = local_clock();
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rem_us = do_div(ts, 1000000000) / 1000;
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priv->buf[0] = cpu_to_be32(ts);
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priv->buf[1] = cpu_to_be32(rem_us);
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spi_message_init_with_transfers(&priv->msg, &priv->xfer, 1);
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priv->msg.complete = spi_slave_time_complete;
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priv->msg.context = priv;
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ret = spi_async(priv->spi, &priv->msg);
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if (ret)
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dev_err(&priv->spi->dev, "spi_async() failed %d\n", ret);
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return ret;
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}
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static int spi_slave_time_probe(struct spi_device *spi)
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{
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struct spi_slave_time_priv *priv;
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int ret;
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priv = devm_kzalloc(&spi->dev, sizeof(*priv), GFP_KERNEL);
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if (!priv)
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return -ENOMEM;
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priv->spi = spi;
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init_completion(&priv->finished);
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priv->xfer.tx_buf = priv->buf;
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priv->xfer.len = sizeof(priv->buf);
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ret = spi_slave_time_submit(priv);
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if (ret)
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return ret;
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spi_set_drvdata(spi, priv);
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return 0;
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}
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static void spi_slave_time_remove(struct spi_device *spi)
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{
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struct spi_slave_time_priv *priv = spi_get_drvdata(spi);
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spi_slave_abort(spi);
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wait_for_completion(&priv->finished);
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}
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static struct spi_driver spi_slave_time_driver = {
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.driver = {
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.name = "spi-slave-time",
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},
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.probe = spi_slave_time_probe,
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.remove = spi_slave_time_remove,
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};
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module_spi_driver(spi_slave_time_driver);
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MODULE_AUTHOR("Geert Uytterhoeven <geert+renesas@glider.be>");
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MODULE_DESCRIPTION("SPI slave reporting uptime at previous SPI message");
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MODULE_LICENSE("GPL v2");
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