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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>
154 lines
3.6 KiB
C
154 lines
3.6 KiB
C
/*
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* SPI slave handler controlling system state
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*
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* This SPI slave handler allows remote control of system reboot, power off,
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* halt, and suspend.
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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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* # reboot='\x7c\x50'
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* # poweroff='\x71\x3f'
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* # halt='\x38\x76'
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* # suspend='\x1b\x1b'
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* # spidev_test -D /dev/spidev2.0 -p $suspend # or $reboot, $poweroff, $halt
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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/reboot.h>
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#include <linux/suspend.h>
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#include <linux/spi/spi.h>
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/*
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* The numbers are chosen to display something human-readable on two 7-segment
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* displays connected to two 74HC595 shift registers
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*/
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#define CMD_REBOOT 0x7c50 /* rb */
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#define CMD_POWEROFF 0x713f /* OF */
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#define CMD_HALT 0x3876 /* HL */
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#define CMD_SUSPEND 0x1b1b /* ZZ */
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struct spi_slave_system_control_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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__be16 cmd;
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};
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static
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int spi_slave_system_control_submit(struct spi_slave_system_control_priv *priv);
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static void spi_slave_system_control_complete(void *arg)
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{
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struct spi_slave_system_control_priv *priv = arg;
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u16 cmd;
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int ret;
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if (priv->msg.status)
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goto terminate;
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cmd = be16_to_cpu(priv->cmd);
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switch (cmd) {
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case CMD_REBOOT:
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dev_info(&priv->spi->dev, "Rebooting system...\n");
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kernel_restart(NULL);
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break;
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case CMD_POWEROFF:
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dev_info(&priv->spi->dev, "Powering off system...\n");
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kernel_power_off();
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break;
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case CMD_HALT:
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dev_info(&priv->spi->dev, "Halting system...\n");
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kernel_halt();
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break;
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case CMD_SUSPEND:
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dev_info(&priv->spi->dev, "Suspending system...\n");
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pm_suspend(PM_SUSPEND_MEM);
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break;
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default:
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dev_warn(&priv->spi->dev, "Unknown command 0x%x\n", cmd);
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break;
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}
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ret = spi_slave_system_control_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
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int spi_slave_system_control_submit(struct spi_slave_system_control_priv *priv)
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{
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int ret;
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spi_message_init_with_transfers(&priv->msg, &priv->xfer, 1);
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priv->msg.complete = spi_slave_system_control_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_system_control_probe(struct spi_device *spi)
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{
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struct spi_slave_system_control_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.rx_buf = &priv->cmd;
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priv->xfer.len = sizeof(priv->cmd);
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ret = spi_slave_system_control_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_system_control_remove(struct spi_device *spi)
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{
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struct spi_slave_system_control_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_system_control_driver = {
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.driver = {
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.name = "spi-slave-system-control",
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},
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.probe = spi_slave_system_control_probe,
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.remove = spi_slave_system_control_remove,
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};
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module_spi_driver(spi_slave_system_control_driver);
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MODULE_AUTHOR("Geert Uytterhoeven <geert+renesas@glider.be>");
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MODULE_DESCRIPTION("SPI slave handler controlling system state");
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MODULE_LICENSE("GPL v2");
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