325 lines
9.1 KiB
C
325 lines
9.1 KiB
C
|
/*
|
||
|
|
* LTC2952 (PowerPath) driver
|
||
|
|
*
|
||
|
|
* Copyright (C) 2014, Xsens Technologies BV <info@xsens.com>
|
||
|
|
* Maintainer: René 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. If no pin is assigned to this input, the driver will start the
|
||
|
|
* watchdog toggle immediately. The chip will only power off the system if
|
||
|
|
* it is requested to do so through the kill line.
|
||
|
|
*
|
||
|
|
* - 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/mod_devicetable.h>
|
||
|
|
#include <linux/gpio/consumer.h>
|
||
|
|
#include <linux/reboot.h>
|
||
|
|
|
||
|
|
struct ltc2952_poweroff {
|
||
|
|
struct hrtimer timer_trigger;
|
||
|
|
struct hrtimer timer_wde;
|
||
|
|
|
||
|
|
ktime_t trigger_delay;
|
||
|
|
ktime_t wde_interval;
|
||
|
|
|
||
|
|
struct device *dev;
|
||
|
|
|
||
|
|
struct gpio_desc *gpio_trigger;
|
||
|
|
struct gpio_desc *gpio_watchdog;
|
||
|
|
struct gpio_desc *gpio_kill;
|
||
|
|
|
||
|
|
bool kernel_panic;
|
||
|
|
struct notifier_block panic_notifier;
|
||
|
|
};
|
||
|
|
|
||
|
|
#define to_ltc2952(p, m) container_of(p, struct ltc2952_poweroff, m)
|
||
|
|
|
||
|
|
/*
|
||
|
|
* This global variable is only needed for pm_power_off. We should
|
||
|
|
* remove it entirely once we don't need the global state anymore.
|
||
|
|
*/
|
||
|
|
static struct ltc2952_poweroff *ltc2952_data;
|
||
|
|
|
||
|
|
/**
|
||
|
|
* 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;
|
||
|
|
struct ltc2952_poweroff *data = to_ltc2952(timer, timer_wde);
|
||
|
|
|
||
|
|
if (data->kernel_panic)
|
||
|
|
return HRTIMER_NORESTART;
|
||
|
|
|
||
|
|
state = gpiod_get_value(data->gpio_watchdog);
|
||
|
|
gpiod_set_value(data->gpio_watchdog, !state);
|
||
|
|
|
||
|
|
now = hrtimer_cb_get_time(timer);
|
||
|
|
overruns = hrtimer_forward(timer, now, data->wde_interval);
|
||
|
|
|
||
|
|
return HRTIMER_RESTART;
|
||
|
|
}
|
||
|
|
|
||
|
|
static void ltc2952_poweroff_start_wde(struct ltc2952_poweroff *data)
|
||
|
|
{
|
||
|
|
hrtimer_start(&data->timer_wde, data->wde_interval, HRTIMER_MODE_REL);
|
||
|
|
}
|
||
|
|
|
||
|
|
static enum hrtimer_restart
|
||
|
|
ltc2952_poweroff_timer_trigger(struct hrtimer *timer)
|
||
|
|
{
|
||
|
|
struct ltc2952_poweroff *data = to_ltc2952(timer, timer_trigger);
|
||
|
|
|
||
|
|
ltc2952_poweroff_start_wde(data);
|
||
|
|
dev_info(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)
|
||
|
|
{
|
||
|
|
struct ltc2952_poweroff *data = dev_id;
|
||
|
|
|
||
|
|
if (data->kernel_panic || hrtimer_active(&data->timer_wde)) {
|
||
|
|
/* shutdown is already triggered, nothing to do any more */
|
||
|
|
return IRQ_HANDLED;
|
||
|
|
}
|
||
|
|
|
||
|
|
if (gpiod_get_value(data->gpio_trigger)) {
|
||
|
|
hrtimer_start(&data->timer_trigger, data->trigger_delay,
|
||
|
|
HRTIMER_MODE_REL);
|
||
|
|
} else {
|
||
|
|
hrtimer_cancel(&data->timer_trigger);
|
||
|
|
}
|
||
|
|
return IRQ_HANDLED;
|
||
|
|
}
|
||
|
|
|
||
|
|
static void ltc2952_poweroff_kill(void)
|
||
|
|
{
|
||
|
|
gpiod_set_value(ltc2952_data->gpio_kill, 1);
|
||
|
|
}
|
||
|
|
|
||
|
|
static void ltc2952_poweroff_default(struct ltc2952_poweroff *data)
|
||
|
|
{
|
||
|
|
data->wde_interval = 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;
|
||
|
|
struct ltc2952_poweroff *data = platform_get_drvdata(pdev);
|
||
|
|
|
||
|
|
ltc2952_poweroff_default(data);
|
||
|
|
|
||
|
|
data->gpio_watchdog = devm_gpiod_get(&pdev->dev, "watchdog",
|
||
|
|
GPIOD_OUT_LOW);
|
||
|
|
if (IS_ERR(data->gpio_watchdog)) {
|
||
|
|
ret = PTR_ERR(data->gpio_watchdog);
|
||
|
|
dev_err(&pdev->dev, "unable to claim gpio \"watchdog\"\n");
|
||
|
|
return ret;
|
||
|
|
}
|
||
|
|
|
||
|
|
data->gpio_kill = devm_gpiod_get(&pdev->dev, "kill", GPIOD_OUT_LOW);
|
||
|
|
if (IS_ERR(data->gpio_kill)) {
|
||
|
|
ret = PTR_ERR(data->gpio_kill);
|
||
|
|
dev_err(&pdev->dev, "unable to claim gpio \"kill\"\n");
|
||
|
|
return ret;
|
||
|
|
}
|
||
|
|
|
||
|
|
data->gpio_trigger = devm_gpiod_get_optional(&pdev->dev, "trigger",
|
||
|
|
GPIOD_IN);
|
||
|
|
if (IS_ERR(data->gpio_trigger)) {
|
||
|
|
/*
|
||
|
|
* It's not a problem if the trigger gpio isn't available, but
|
||
|
|
* it is worth a warning if its use was defined in the device
|
||
|
|
* tree.
|
||
|
|
*/
|
||
|
|
dev_err(&pdev->dev, "unable to claim gpio \"trigger\"\n");
|
||
|
|
data->gpio_trigger = NULL;
|
||
|
|
}
|
||
|
|
|
||
|
|
if (devm_request_irq(&pdev->dev, gpiod_to_irq(data->gpio_trigger),
|
||
|
|
ltc2952_poweroff_handler,
|
||
|
|
(IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING),
|
||
|
|
"ltc2952-poweroff",
|
||
|
|
data)) {
|
||
|
|
/*
|
||
|
|
* Some things may have happened:
|
||
|
|
* - No trigger input was defined
|
||
|
|
* - Claiming the GPIO failed
|
||
|
|
* - We could not map to an IRQ
|
||
|
|
* - We couldn't register an interrupt handler
|
||
|
|
*
|
||
|
|
* None of these really are problems, but all of them
|
||
|
|
* disqualify the push button from controlling the power.
|
||
|
|
*
|
||
|
|
* It is therefore important to note that if the ltc2952
|
||
|
|
* detects a button press for long enough, it will still start
|
||
|
|
* its own powerdown window and cut the power on us if we don't
|
||
|
|
* start the watchdog trigger.
|
||
|
|
*/
|
||
|
|
if (data->gpio_trigger) {
|
||
|
|
dev_warn(&pdev->dev,
|
||
|
|
"unable to configure the trigger interrupt\n");
|
||
|
|
devm_gpiod_put(&pdev->dev, data->gpio_trigger);
|
||
|
|
data->gpio_trigger = NULL;
|
||
|
|
}
|
||
|
|
dev_info(&pdev->dev,
|
||
|
|
"power down trigger input will not be used\n");
|
||
|
|
ltc2952_poweroff_start_wde(data);
|
||
|
|
}
|
||
|
|
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
static int ltc2952_poweroff_notify_panic(struct notifier_block *nb,
|
||
|
|
unsigned long code, void *unused)
|
||
|
|
{
|
||
|
|
struct ltc2952_poweroff *data = to_ltc2952(nb, panic_notifier);
|
||
|
|
|
||
|
|
data->kernel_panic = true;
|
||
|
|
return NOTIFY_DONE;
|
||
|
|
}
|
||
|
|
|
||
|
|
static int ltc2952_poweroff_probe(struct platform_device *pdev)
|
||
|
|
{
|
||
|
|
int ret;
|
||
|
|
struct ltc2952_poweroff *data;
|
||
|
|
|
||
|
|
if (pm_power_off) {
|
||
|
|
dev_err(&pdev->dev, "pm_power_off already registered");
|
||
|
|
return -EBUSY;
|
||
|
|
}
|
||
|
|
|
||
|
|
data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
|
||
|
|
if (!data)
|
||
|
|
return -ENOMEM;
|
||
|
|
|
||
|
|
data->dev = &pdev->dev;
|
||
|
|
platform_set_drvdata(pdev, data);
|
||
|
|
|
||
|
|
ret = ltc2952_poweroff_init(pdev);
|
||
|
|
if (ret)
|
||
|
|
return ret;
|
||
|
|
|
||
|
|
/* TODO: remove ltc2952_data */
|
||
|
|
ltc2952_data = data;
|
||
|
|
pm_power_off = ltc2952_poweroff_kill;
|
||
|
|
|
||
|
|
data->panic_notifier.notifier_call = ltc2952_poweroff_notify_panic;
|
||
|
|
atomic_notifier_chain_register(&panic_notifier_list,
|
||
|
|
&data->panic_notifier);
|
||
|
|
dev_info(&pdev->dev, "probe successful\n");
|
||
|
|
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
static int ltc2952_poweroff_remove(struct platform_device *pdev)
|
||
|
|
{
|
||
|
|
struct ltc2952_poweroff *data = platform_get_drvdata(pdev);
|
||
|
|
|
||
|
|
pm_power_off = NULL;
|
||
|
|
hrtimer_cancel(&data->timer_trigger);
|
||
|
|
hrtimer_cancel(&data->timer_wde);
|
||
|
|
atomic_notifier_chain_unregister(&panic_notifier_list,
|
||
|
|
&data->panic_notifier);
|
||
|
|
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",
|
||
|
|
.of_match_table = of_ltc2952_poweroff_match,
|
||
|
|
},
|
||
|
|
};
|
||
|
|
|
||
|
|
module_platform_driver(ltc2952_poweroff_driver);
|
||
|
|
|
||
|
|
MODULE_AUTHOR("René Moll <rene.moll@xsens.com>");
|
||
|
|
MODULE_DESCRIPTION("LTC PowerPath power-off driver");
|
||
|
|
MODULE_LICENSE("GPL v2");
|