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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,154 @@ | ||
| /* | ||
| * SPI slave handler controlling system state | ||
| * | ||
| * This SPI slave handler allows remote control of system reboot, power off, | ||
| * halt, and suspend. | ||
| * | ||
| * Copyright (C) 2016-2017 Glider bvba | ||
| * | ||
| * This file is subject to the terms and conditions of the GNU General Public | ||
| * License. See the file "COPYING" in the main directory of this archive | ||
| * for more details. | ||
| * | ||
| * Usage (assuming /dev/spidev2.0 corresponds to the SPI master on the remote | ||
| * system): | ||
| * | ||
| * # reboot='\x7c\x50' | ||
| * # poweroff='\x71\x3f' | ||
| * # halt='\x38\x76' | ||
| * # suspend='\x1b\x1b' | ||
| * # spidev_test -D /dev/spidev2.0 -p $suspend # or $reboot, $poweroff, $halt | ||
| */ | ||
|
|
||
| #include <linux/completion.h> | ||
| #include <linux/module.h> | ||
| #include <linux/reboot.h> | ||
| #include <linux/suspend.h> | ||
| #include <linux/spi/spi.h> | ||
|
|
||
| /* | ||
| * The numbers are chosen to display something human-readable on two 7-segment | ||
| * displays connected to two 74HC595 shift registers | ||
| */ | ||
| #define CMD_REBOOT 0x7c50 /* rb */ | ||
| #define CMD_POWEROFF 0x713f /* OF */ | ||
| #define CMD_HALT 0x3876 /* HL */ | ||
| #define CMD_SUSPEND 0x1b1b /* ZZ */ | ||
|
|
||
| struct spi_slave_system_control_priv { | ||
| struct spi_device *spi; | ||
| struct completion finished; | ||
| struct spi_transfer xfer; | ||
| struct spi_message msg; | ||
| __be16 cmd; | ||
| }; | ||
|
|
||
| static | ||
| int spi_slave_system_control_submit(struct spi_slave_system_control_priv *priv); | ||
|
|
||
| static void spi_slave_system_control_complete(void *arg) | ||
| { | ||
| struct spi_slave_system_control_priv *priv = arg; | ||
| u16 cmd; | ||
| int ret; | ||
|
|
||
| if (priv->msg.status) | ||
| goto terminate; | ||
|
|
||
| cmd = be16_to_cpu(priv->cmd); | ||
| switch (cmd) { | ||
| case CMD_REBOOT: | ||
| dev_info(&priv->spi->dev, "Rebooting system...\n"); | ||
| kernel_restart(NULL); | ||
|
|
||
| case CMD_POWEROFF: | ||
| dev_info(&priv->spi->dev, "Powering off system...\n"); | ||
| kernel_power_off(); | ||
| break; | ||
|
|
||
| case CMD_HALT: | ||
| dev_info(&priv->spi->dev, "Halting system...\n"); | ||
| kernel_halt(); | ||
| break; | ||
|
|
||
| case CMD_SUSPEND: | ||
| dev_info(&priv->spi->dev, "Suspending system...\n"); | ||
| pm_suspend(PM_SUSPEND_MEM); | ||
| break; | ||
|
|
||
| default: | ||
| dev_warn(&priv->spi->dev, "Unknown command 0x%x\n", cmd); | ||
| break; | ||
| } | ||
|
|
||
| ret = spi_slave_system_control_submit(priv); | ||
| if (ret) | ||
| goto terminate; | ||
|
|
||
| return; | ||
|
|
||
| terminate: | ||
| dev_info(&priv->spi->dev, "Terminating\n"); | ||
| complete(&priv->finished); | ||
| } | ||
|
|
||
| static | ||
| int spi_slave_system_control_submit(struct spi_slave_system_control_priv *priv) | ||
| { | ||
| int ret; | ||
|
|
||
| spi_message_init_with_transfers(&priv->msg, &priv->xfer, 1); | ||
|
|
||
| priv->msg.complete = spi_slave_system_control_complete; | ||
| priv->msg.context = priv; | ||
|
|
||
| ret = spi_async(priv->spi, &priv->msg); | ||
| if (ret) | ||
| dev_err(&priv->spi->dev, "spi_async() failed %d\n", ret); | ||
|
|
||
| return ret; | ||
| } | ||
|
|
||
| static int spi_slave_system_control_probe(struct spi_device *spi) | ||
| { | ||
| struct spi_slave_system_control_priv *priv; | ||
| int ret; | ||
|
|
||
| priv = devm_kzalloc(&spi->dev, sizeof(*priv), GFP_KERNEL); | ||
| if (!priv) | ||
| return -ENOMEM; | ||
|
|
||
| priv->spi = spi; | ||
| init_completion(&priv->finished); | ||
| priv->xfer.rx_buf = &priv->cmd; | ||
| priv->xfer.len = sizeof(priv->cmd); | ||
|
|
||
| ret = spi_slave_system_control_submit(priv); | ||
| if (ret) | ||
| return ret; | ||
|
|
||
| spi_set_drvdata(spi, priv); | ||
| return 0; | ||
| } | ||
|
|
||
| static int spi_slave_system_control_remove(struct spi_device *spi) | ||
| { | ||
| struct spi_slave_system_control_priv *priv = spi_get_drvdata(spi); | ||
|
|
||
| spi_slave_abort(spi); | ||
| wait_for_completion(&priv->finished); | ||
| return 0; | ||
| } | ||
|
|
||
| static struct spi_driver spi_slave_system_control_driver = { | ||
| .driver = { | ||
| .name = "spi-slave-system-control", | ||
| }, | ||
| .probe = spi_slave_system_control_probe, | ||
| .remove = spi_slave_system_control_remove, | ||
| }; | ||
| module_spi_driver(spi_slave_system_control_driver); | ||
|
|
||
| MODULE_AUTHOR("Geert Uytterhoeven <[email protected]>"); | ||
| MODULE_DESCRIPTION("SPI slave handler controlling system state"); | ||
| MODULE_LICENSE("GPL v2"); |
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