power: reset: add LTC2952 poweroff driver (6647156c) · Commits · e / devices / android_kernel_oneplus_sm7250

drivers/power/reset/Kconfig

+7 −0

Original line number	Diff line number	Diff line
		@@ -51,6 +51,13 @@ config POWER_RESET_MSM
		help
		Power off and restart support for Qualcomm boards.

		config POWER_RESET_LTC2952
		bool "LTC2952 PowerPath power-off driver"
		depends on OF_GPIO && POWER_RESET
		help
		This driver supports an external powerdown trigger and board power
		down via the LTC2952. Bindings are made in the device tree.

		config POWER_RESET_QNAP
		bool "QNAP power-off driver"
		depends on OF_GPIO && POWER_RESET && PLAT_ORION

drivers/power/reset/Makefile

+1 −0

Original line number	Diff line number	Diff line
		@@ -4,6 +4,7 @@ obj-$(CONFIG_POWER_RESET_BRCMSTB) += brcmstb-reboot.o
		obj-$(CONFIG_POWER_RESET_GPIO) += gpio-poweroff.o
		obj-$(CONFIG_POWER_RESET_HISI) += hisi-reboot.o
		obj-$(CONFIG_POWER_RESET_MSM) += msm-poweroff.o
		obj-$(CONFIG_POWER_RESET_LTC2952) += ltc2952-poweroff.o
		obj-$(CONFIG_POWER_RESET_QNAP) += qnap-poweroff.o
		obj-$(CONFIG_POWER_RESET_RESTART) += restart-poweroff.o
		obj-$(CONFIG_POWER_RESET_SUN6I) += sun6i-reboot.o

drivers/power/reset/ltc2952-poweroff.c

0 → 100644

+386 −0

Original line number	Diff line number	Diff line
		/*
		* LTC2952 (PowerPath) driver
		*
		* Copyright (C) 2014, Xsens Technologies BV <info@xsens.com>
		* Maintainer: Ren Moll <linux@r-moll.nl>
		*
		* This program is free software; you can redistribute it and/or
		* modify it under the terms of the GNU General Public License
		* as published by the Free Software Foundation; either version 2
		* of the License, or (at your option) any later version.
		*
		* This program is distributed in the hope that it will be useful,
		* but WITHOUT ANY WARRANTY; without even the implied warranty of
		* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
		* GNU General Public License for more details.
		*
		* ----------------------------------------
		* - Description
		* ----------------------------------------
		*
		* This driver is to be used with an external PowerPath Controller (LTC2952).
		* Its function is to determine when a external shut down is triggered
		* and react by properly shutting down the system.
		*
		* This driver expects a device tree with a ltc2952 entry for pin mapping.
		*
		* ----------------------------------------
		* - GPIO
		* ----------------------------------------
		*
		* The following GPIOs are used:
		* - trigger (input)
		* A level change indicates the shut-down trigger. If it's state reverts
		* within the time-out defined by trigger_delay, the shut down is not
		* executed.
		*
		* - watchdog (output)
		* Once a shut down is triggered, the driver will toggle this signal,
		* with an internal (wde_interval) to stall the hardware shut down.
		*
		* - kill (output)
		* The last action during shut down is triggering this signalling, such
		* that the PowerPath Control will power down the hardware.
		*
		* ----------------------------------------
		* - Interrupts
		* ----------------------------------------
		*
		* The driver requires a non-shared, edge-triggered interrupt on the trigger
		* GPIO.
		*
		*/

		#include <linux/kernel.h>
		#include <linux/init.h>
		#include <linux/interrupt.h>
		#include <linux/device.h>
		#include <linux/platform_device.h>
		#include <linux/ktime.h>
		#include <linux/slab.h>
		#include <linux/kmod.h>
		#include <linux/module.h>
		#include <linux/gpio/consumer.h>
		#include <linux/reboot.h>

		struct ltc2952_poweroff_data {
		struct hrtimer timer_trigger;
		struct hrtimer timer_wde;

		ktime_t trigger_delay;
		ktime_t wde_interval;

		struct device *dev;

		unsigned int virq;

		/**
		* 0: trigger
		* 1: watchdog
		* 2: kill
		*/
		struct gpio_desc *gpio[3];
		};

		static int ltc2952_poweroff_panic;
		static struct ltc2952_poweroff_data *ltc2952_data;

		#define POWERPATH_IO_TRIGGER 0
		#define POWERPATH_IO_WATCHDOG 1
		#define POWERPATH_IO_KILL 2

		/**
		* ltc2952_poweroff_timer_wde - Timer callback
		* Toggles the watchdog reset signal each wde_interval
		*
		* @timer: corresponding timer
		*
		* Returns HRTIMER_RESTART for an infinite loop which will only stop when the
		* machine actually shuts down
		*/
		static enum hrtimer_restart ltc2952_poweroff_timer_wde(struct hrtimer *timer)
		{
		ktime_t now;
		int state;
		unsigned long overruns;

		if (ltc2952_poweroff_panic)
		return HRTIMER_NORESTART;

		state = gpiod_get_value(ltc2952_data->gpio[POWERPATH_IO_WATCHDOG]);
		gpiod_set_value(ltc2952_data->gpio[POWERPATH_IO_WATCHDOG], !state);

		now = hrtimer_cb_get_time(timer);
		overruns = hrtimer_forward(timer, now, ltc2952_data->wde_interval);

		return HRTIMER_RESTART;
		}

		static enum hrtimer_restart ltc2952_poweroff_timer_trigger(
		struct hrtimer *timer)
		{
		int ret;

		ret = hrtimer_start(&ltc2952_data->timer_wde,
		ltc2952_data->wde_interval, HRTIMER_MODE_REL);

		if (ret) {
		dev_err(ltc2952_data->dev, "unable to start the timer\n");
		/*
		* The device will not toggle the watchdog reset,
		* thus shut down is only safe if the PowerPath controller
		* has a long enough time-off before triggering a hardware
		* power-off.
		*
		* Only sending a warning as the system will power-off anyway
		*/
		}

		dev_info(ltc2952_data->dev, "executing shutdown\n");

		orderly_poweroff(true);

		return HRTIMER_NORESTART;
		}

		/**
		* ltc2952_poweroff_handler - Interrupt handler
		* Triggered each time the trigger signal changes state and (de)activates a
		* time-out (timer_trigger). Once the time-out is actually reached the shut
		* down is executed.
		*
		* @irq: IRQ number
		* @dev_id: pointer to the main data structure
		*/
		static irqreturn_t ltc2952_poweroff_handler(int irq, void *dev_id)
		{
		int ret;
		struct ltc2952_poweroff_data *data = dev_id;

		if (ltc2952_poweroff_panic)
		goto irq_ok;

		if (hrtimer_active(&data->timer_wde)) {
		/* shutdown is already triggered, nothing to do any more */
		goto irq_ok;
		}

		if (!hrtimer_active(&data->timer_trigger)) {
		ret = hrtimer_start(&data->timer_trigger, data->trigger_delay,
		HRTIMER_MODE_REL);

		if (ret)
		dev_err(data->dev, "unable to start the wait timer\n");
		} else {
		ret = hrtimer_cancel(&data->timer_trigger);
		/* omitting return value check, timer should have been valid */
		}

		irq_ok:
		return IRQ_HANDLED;
		}

		static void ltc2952_poweroff_kill(void)
		{
		gpiod_set_value(ltc2952_data->gpio[POWERPATH_IO_KILL], 1);
		}

		static int ltc2952_poweroff_suspend(struct platform_device *pdev,
		pm_message_t state)
		{
		return -ENOSYS;
		}

		static int ltc2952_poweroff_resume(struct platform_device *pdev)
		{
		return -ENOSYS;
		}

		static void ltc2952_poweroff_default(struct ltc2952_poweroff_data *data)
		{
		unsigned int i;

		for (i = 0; i < ARRAY_SIZE(data->gpio); i++)
		data->gpio[i] = NULL;

		data->wde_interval = ktime_set(0, 300L*1E6L);
		data->trigger_delay = ktime_set(2, 500L*1E6L);

		hrtimer_init(&data->timer_trigger, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
		data->timer_trigger.function = &ltc2952_poweroff_timer_trigger;

		hrtimer_init(&data->timer_wde, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
		data->timer_wde.function = &ltc2952_poweroff_timer_wde;
		}

		static int ltc2952_poweroff_init(struct platform_device *pdev)
		{
		int ret, virq;
		unsigned int i;
		struct ltc2952_poweroff_data *data;

		static char *name[] = {
		"trigger",
		"watchdog",
		"kill",
		NULL
		};

		data = ltc2952_data;
		ltc2952_poweroff_default(ltc2952_data);

		for (i = 0; i < ARRAY_SIZE(ltc2952_data->gpio); i++) {
		ltc2952_data->gpio[i] = gpiod_get(&pdev->dev, name[i]);

		if (IS_ERR(ltc2952_data->gpio[i])) {
		ret = PTR_ERR(ltc2952_data->gpio[i]);
		dev_err(&pdev->dev,
		"unable to claim the following gpio: %s\n",
		name[i]);
		goto err_io;
		}
		}

		ret = gpiod_direction_output(
		ltc2952_data->gpio[POWERPATH_IO_WATCHDOG], 0);
		if (ret) {
		dev_err(&pdev->dev, "unable to use watchdog-gpio as output\n");
		goto err_io;
		}

		ret = gpiod_direction_output(ltc2952_data->gpio[POWERPATH_IO_KILL], 0);
		if (ret) {
		dev_err(&pdev->dev, "unable to use kill-gpio as output\n");
		goto err_io;
		}

		virq = gpiod_to_irq(ltc2952_data->gpio[POWERPATH_IO_TRIGGER]);
		if (virq < 0) {
		dev_err(&pdev->dev, "cannot map GPIO as interrupt");
		goto err_io;
		}

		ltc2952_data->virq = virq;
		ret = request_irq(virq,
		ltc2952_poweroff_handler,
		(IRQF_TRIGGER_FALLING \| IRQF_TRIGGER_RISING),
		"ltc2952-poweroff",
		ltc2952_data
		);

		if (ret) {
		dev_err(&pdev->dev, "cannot configure an interrupt handler\n");
		goto err_io;
		}

		return 0;

		err_io:
		for (i = 0; i < ARRAY_SIZE(ltc2952_data->gpio); i++)
		if (ltc2952_data->gpio[i])
		gpiod_put(ltc2952_data->gpio[i]);

		return ret;
		}

		static int ltc2952_poweroff_probe(struct platform_device *pdev)
		{
		int ret;

		if (pm_power_off) {
		dev_err(&pdev->dev, "pm_power_off already registered");
		return -EBUSY;
		}

		ltc2952_data = kzalloc(sizeof(*ltc2952_data), GFP_KERNEL);
		if (!ltc2952_data)
		return -ENOMEM;

		ltc2952_data->dev = &pdev->dev;

		ret = ltc2952_poweroff_init(pdev);
		if (ret)
		goto err;

		pm_power_off = &ltc2952_poweroff_kill;

		dev_info(&pdev->dev, "probe successful\n");

		return 0;

		err:
		kfree(ltc2952_data);
		return ret;
		}

		static int ltc2952_poweroff_remove(struct platform_device *pdev)
		{
		unsigned int i;

		pm_power_off = NULL;

		if (ltc2952_data) {
		free_irq(ltc2952_data->virq, ltc2952_data);

		for (i = 0; i < ARRAY_SIZE(ltc2952_data->gpio); i++)
		gpiod_put(ltc2952_data->gpio[i]);

		kfree(ltc2952_data);
		}

		return 0;
		}

		static const struct of_device_id of_ltc2952_poweroff_match[] = {
		{ .compatible = "lltc,ltc2952"},
		{},
		};
		MODULE_DEVICE_TABLE(of, of_ltc2952_poweroff_match);

		static struct platform_driver ltc2952_poweroff_driver = {
		.probe = ltc2952_poweroff_probe,
		.remove = ltc2952_poweroff_remove,
		.driver = {
		.name = "ltc2952-poweroff",
		.owner = THIS_MODULE,
		.of_match_table = of_ltc2952_poweroff_match,
		},
		.suspend = ltc2952_poweroff_suspend,
		.resume = ltc2952_poweroff_resume,
		};

		static int ltc2952_poweroff_notify_panic(struct notifier_block *nb,
		unsigned long code, void *unused)
		{
		ltc2952_poweroff_panic = 1;
		return NOTIFY_DONE;
		}

		static struct notifier_block ltc2952_poweroff_panic_nb = {
		.notifier_call = ltc2952_poweroff_notify_panic,
		};

		static int __init ltc2952_poweroff_platform_init(void)
		{
		ltc2952_poweroff_panic = 0;

		atomic_notifier_chain_register(&panic_notifier_list,
		&ltc2952_poweroff_panic_nb);

		return platform_driver_register(&ltc2952_poweroff_driver);
		}

		static void __exit ltc2952_poweroff_platform_exit(void)
		{
		atomic_notifier_chain_unregister(&panic_notifier_list,
		&ltc2952_poweroff_panic_nb);

		platform_driver_unregister(&ltc2952_poweroff_driver);
		}

		module_init(ltc2952_poweroff_platform_init);
		module_exit(ltc2952_poweroff_platform_exit);

		MODULE_AUTHOR("Ren Moll <rene.moll@xsens.com>");
		MODULE_DESCRIPTION("LTC PowerPath power-off driver");
		MODULE_LICENSE("GPL v2");