387 lines
9.3 KiB
C
387 lines
9.3 KiB
C
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/*
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* LTC2952 (PowerPath) driver
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*
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* Copyright (C) 2014, Xsens Technologies BV <info@xsens.com>
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* Maintainer: Ren<EFBFBD> Moll <linux@r-moll.nl>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* ----------------------------------------
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* - Description
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* ----------------------------------------
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*
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* This driver is to be used with an external PowerPath Controller (LTC2952).
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* Its function is to determine when a external shut down is triggered
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* and react by properly shutting down the system.
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*
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* This driver expects a device tree with a ltc2952 entry for pin mapping.
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*
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* ----------------------------------------
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* - GPIO
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* ----------------------------------------
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*
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* The following GPIOs are used:
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* - trigger (input)
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* A level change indicates the shut-down trigger. If it's state reverts
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* within the time-out defined by trigger_delay, the shut down is not
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* executed.
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*
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* - watchdog (output)
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* Once a shut down is triggered, the driver will toggle this signal,
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* with an internal (wde_interval) to stall the hardware shut down.
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*
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* - kill (output)
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* The last action during shut down is triggering this signalling, such
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* that the PowerPath Control will power down the hardware.
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*
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* ----------------------------------------
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* - Interrupts
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* ----------------------------------------
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*
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* The driver requires a non-shared, edge-triggered interrupt on the trigger
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* GPIO.
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*
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*/
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#include <linux/kernel.h>
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#include <linux/init.h>
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#include <linux/interrupt.h>
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#include <linux/device.h>
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#include <linux/platform_device.h>
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#include <linux/ktime.h>
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#include <linux/slab.h>
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#include <linux/kmod.h>
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#include <linux/module.h>
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#include <linux/gpio/consumer.h>
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#include <linux/reboot.h>
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struct ltc2952_poweroff_data {
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struct hrtimer timer_trigger;
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struct hrtimer timer_wde;
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ktime_t trigger_delay;
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ktime_t wde_interval;
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struct device *dev;
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unsigned int virq;
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/**
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* 0: trigger
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* 1: watchdog
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* 2: kill
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*/
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struct gpio_desc *gpio[3];
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};
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static int ltc2952_poweroff_panic;
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static struct ltc2952_poweroff_data *ltc2952_data;
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#define POWERPATH_IO_TRIGGER 0
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#define POWERPATH_IO_WATCHDOG 1
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#define POWERPATH_IO_KILL 2
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/**
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* ltc2952_poweroff_timer_wde - Timer callback
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* Toggles the watchdog reset signal each wde_interval
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*
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* @timer: corresponding timer
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*
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* Returns HRTIMER_RESTART for an infinite loop which will only stop when the
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* machine actually shuts down
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*/
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static enum hrtimer_restart ltc2952_poweroff_timer_wde(struct hrtimer *timer)
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{
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ktime_t now;
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int state;
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unsigned long overruns;
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if (ltc2952_poweroff_panic)
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return HRTIMER_NORESTART;
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state = gpiod_get_value(ltc2952_data->gpio[POWERPATH_IO_WATCHDOG]);
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gpiod_set_value(ltc2952_data->gpio[POWERPATH_IO_WATCHDOG], !state);
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now = hrtimer_cb_get_time(timer);
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overruns = hrtimer_forward(timer, now, ltc2952_data->wde_interval);
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return HRTIMER_RESTART;
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}
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static enum hrtimer_restart ltc2952_poweroff_timer_trigger(
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struct hrtimer *timer)
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{
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int ret;
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ret = hrtimer_start(<c2952_data->timer_wde,
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ltc2952_data->wde_interval, HRTIMER_MODE_REL);
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if (ret) {
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dev_err(ltc2952_data->dev, "unable to start the timer\n");
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/*
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* The device will not toggle the watchdog reset,
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* thus shut down is only safe if the PowerPath controller
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* has a long enough time-off before triggering a hardware
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* power-off.
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*
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* Only sending a warning as the system will power-off anyway
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*/
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}
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dev_info(ltc2952_data->dev, "executing shutdown\n");
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orderly_poweroff(true);
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return HRTIMER_NORESTART;
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}
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/**
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* ltc2952_poweroff_handler - Interrupt handler
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* Triggered each time the trigger signal changes state and (de)activates a
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* time-out (timer_trigger). Once the time-out is actually reached the shut
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* down is executed.
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*
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* @irq: IRQ number
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* @dev_id: pointer to the main data structure
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*/
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static irqreturn_t ltc2952_poweroff_handler(int irq, void *dev_id)
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{
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int ret;
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struct ltc2952_poweroff_data *data = dev_id;
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if (ltc2952_poweroff_panic)
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goto irq_ok;
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if (hrtimer_active(&data->timer_wde)) {
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/* shutdown is already triggered, nothing to do any more */
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goto irq_ok;
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}
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if (!hrtimer_active(&data->timer_trigger)) {
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ret = hrtimer_start(&data->timer_trigger, data->trigger_delay,
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HRTIMER_MODE_REL);
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if (ret)
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dev_err(data->dev, "unable to start the wait timer\n");
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} else {
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ret = hrtimer_cancel(&data->timer_trigger);
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/* omitting return value check, timer should have been valid */
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}
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irq_ok:
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return IRQ_HANDLED;
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}
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static void ltc2952_poweroff_kill(void)
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{
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gpiod_set_value(ltc2952_data->gpio[POWERPATH_IO_KILL], 1);
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}
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static int ltc2952_poweroff_suspend(struct platform_device *pdev,
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pm_message_t state)
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{
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return -ENOSYS;
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}
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static int ltc2952_poweroff_resume(struct platform_device *pdev)
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{
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return -ENOSYS;
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}
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static void ltc2952_poweroff_default(struct ltc2952_poweroff_data *data)
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{
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unsigned int i;
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for (i = 0; i < ARRAY_SIZE(data->gpio); i++)
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data->gpio[i] = NULL;
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data->wde_interval = ktime_set(0, 300L*1E6L);
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data->trigger_delay = ktime_set(2, 500L*1E6L);
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hrtimer_init(&data->timer_trigger, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
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data->timer_trigger.function = <c2952_poweroff_timer_trigger;
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hrtimer_init(&data->timer_wde, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
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data->timer_wde.function = <c2952_poweroff_timer_wde;
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}
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static int ltc2952_poweroff_init(struct platform_device *pdev)
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{
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int ret, virq;
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unsigned int i;
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struct ltc2952_poweroff_data *data;
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static char *name[] = {
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"trigger",
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"watchdog",
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"kill",
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NULL
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};
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data = ltc2952_data;
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ltc2952_poweroff_default(ltc2952_data);
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for (i = 0; i < ARRAY_SIZE(ltc2952_data->gpio); i++) {
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ltc2952_data->gpio[i] = gpiod_get(&pdev->dev, name[i]);
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if (IS_ERR(ltc2952_data->gpio[i])) {
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ret = PTR_ERR(ltc2952_data->gpio[i]);
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dev_err(&pdev->dev,
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"unable to claim the following gpio: %s\n",
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name[i]);
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goto err_io;
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}
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}
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ret = gpiod_direction_output(
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ltc2952_data->gpio[POWERPATH_IO_WATCHDOG], 0);
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if (ret) {
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dev_err(&pdev->dev, "unable to use watchdog-gpio as output\n");
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goto err_io;
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}
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ret = gpiod_direction_output(ltc2952_data->gpio[POWERPATH_IO_KILL], 0);
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if (ret) {
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dev_err(&pdev->dev, "unable to use kill-gpio as output\n");
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goto err_io;
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}
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virq = gpiod_to_irq(ltc2952_data->gpio[POWERPATH_IO_TRIGGER]);
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if (virq < 0) {
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dev_err(&pdev->dev, "cannot map GPIO as interrupt");
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goto err_io;
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}
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ltc2952_data->virq = virq;
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ret = request_irq(virq,
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ltc2952_poweroff_handler,
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(IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING),
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"ltc2952-poweroff",
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ltc2952_data
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);
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if (ret) {
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dev_err(&pdev->dev, "cannot configure an interrupt handler\n");
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goto err_io;
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}
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return 0;
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err_io:
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for (i = 0; i < ARRAY_SIZE(ltc2952_data->gpio); i++)
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if (ltc2952_data->gpio[i])
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gpiod_put(ltc2952_data->gpio[i]);
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return ret;
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}
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static int ltc2952_poweroff_probe(struct platform_device *pdev)
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{
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int ret;
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if (pm_power_off) {
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dev_err(&pdev->dev, "pm_power_off already registered");
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return -EBUSY;
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}
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ltc2952_data = kzalloc(sizeof(*ltc2952_data), GFP_KERNEL);
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if (!ltc2952_data)
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return -ENOMEM;
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ltc2952_data->dev = &pdev->dev;
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ret = ltc2952_poweroff_init(pdev);
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if (ret)
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goto err;
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pm_power_off = <c2952_poweroff_kill;
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dev_info(&pdev->dev, "probe successful\n");
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return 0;
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err:
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kfree(ltc2952_data);
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return ret;
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}
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static int ltc2952_poweroff_remove(struct platform_device *pdev)
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{
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unsigned int i;
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pm_power_off = NULL;
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if (ltc2952_data) {
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free_irq(ltc2952_data->virq, ltc2952_data);
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for (i = 0; i < ARRAY_SIZE(ltc2952_data->gpio); i++)
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gpiod_put(ltc2952_data->gpio[i]);
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kfree(ltc2952_data);
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}
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return 0;
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}
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static const struct of_device_id of_ltc2952_poweroff_match[] = {
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{ .compatible = "lltc,ltc2952"},
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{},
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};
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MODULE_DEVICE_TABLE(of, of_ltc2952_poweroff_match);
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static struct platform_driver ltc2952_poweroff_driver = {
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.probe = ltc2952_poweroff_probe,
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.remove = ltc2952_poweroff_remove,
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.driver = {
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.name = "ltc2952-poweroff",
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.owner = THIS_MODULE,
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.of_match_table = of_ltc2952_poweroff_match,
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},
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.suspend = ltc2952_poweroff_suspend,
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.resume = ltc2952_poweroff_resume,
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};
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static int ltc2952_poweroff_notify_panic(struct notifier_block *nb,
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unsigned long code, void *unused)
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{
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ltc2952_poweroff_panic = 1;
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return NOTIFY_DONE;
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}
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static struct notifier_block ltc2952_poweroff_panic_nb = {
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.notifier_call = ltc2952_poweroff_notify_panic,
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};
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static int __init ltc2952_poweroff_platform_init(void)
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{
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ltc2952_poweroff_panic = 0;
|
|||
|
|
|
|||
|
|
atomic_notifier_chain_register(&panic_notifier_list,
|
|||
|
|
<c2952_poweroff_panic_nb);
|
|||
|
|
|
|||
|
|
return platform_driver_register(<c2952_poweroff_driver);
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
static void __exit ltc2952_poweroff_platform_exit(void)
|
|||
|
|
{
|
|||
|
|
atomic_notifier_chain_unregister(&panic_notifier_list,
|
|||
|
|
<c2952_poweroff_panic_nb);
|
|||
|
|
|
|||
|
|
platform_driver_unregister(<c2952_poweroff_driver);
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
module_init(ltc2952_poweroff_platform_init);
|
|||
|
|
module_exit(ltc2952_poweroff_platform_exit);
|
|||
|
|
|
|||
|
|
MODULE_AUTHOR("Ren<EFBFBD> Moll <rene.moll@xsens.com>");
|
|||
|
|
MODULE_DESCRIPTION("LTC PowerPath power-off driver");
|
|||
|
|
MODULE_LICENSE("GPL v2");
|