1 // SPDX-License-Identifier: GPL-2.0-or-later
6  * Maintainer: René Moll <linux@r-moll.nl>
8  * ----------------------------------------
9  * - Description
10  * ----------------------------------------
13  * Its function is to determine when a external shut down is triggered
14  * and react by properly shutting down the system.
18  * ----------------------------------------
19  * - GPIO
20  * ----------------------------------------
22  * The following GPIOs are used:
23  * - trigger (input)
24  *     A level change indicates the shut-down trigger. If it's state reverts
25  *     within the time-out defined by trigger_delay, the shut down is not
30  * - watchdog (output)
31  *     Once a shut down is triggered, the driver will toggle this signal,
32  *     with an internal (wde_interval) to stall the hardware shut down.
34  * - kill (output)
35  *     The last action during shut down is triggering this signalling, such
36  *     that the PowerPath Control will power down the hardware.
38  * ----------------------------------------
39  * - Interrupts
40  * ----------------------------------------
42  * The driver requires a non-shared, edge-triggered interrupt on the trigger
87  * ltc2952_poweroff_timer_wde - Timer callback
93  * machine actually shuts down
100 	if (data->kernel_panic)  in ltc2952_poweroff_timer_wde()
103 	state = gpiod_get_value(data->gpio_watchdog);  in ltc2952_poweroff_timer_wde()
104 	gpiod_set_value(data->gpio_watchdog, !state);  in ltc2952_poweroff_timer_wde()
106 	hrtimer_forward_now(timer, data->wde_interval);  in ltc2952_poweroff_timer_wde()
113 	hrtimer_start(&data->timer_wde, data->wde_interval, HRTIMER_MODE_REL);  in ltc2952_poweroff_start_wde()
122 	dev_info(data->dev, "executing shutdown\n");  in ltc2952_poweroff_timer_trigger()
129  * ltc2952_poweroff_handler - Interrupt handler
131  * time-out (timer_trigger). Once the time-out is actually reached the shut
132  * down is executed.
141 	if (data->kernel_panic || hrtimer_active(&data->timer_wde)) {  in ltc2952_poweroff_handler()
146 	if (gpiod_get_value(data->gpio_trigger)) {  in ltc2952_poweroff_handler()
147 		hrtimer_start(&data->timer_trigger, data->trigger_delay,  in ltc2952_poweroff_handler()
150 		hrtimer_cancel(&data->timer_trigger);  in ltc2952_poweroff_handler()
157 	gpiod_set_value(ltc2952_data->gpio_kill, 1);  in ltc2952_poweroff_kill()
162 	data->wde_interval = 300L * NSEC_PER_MSEC;  in ltc2952_poweroff_default()
163 	data->trigger_delay = ktime_set(2, 500L * NSEC_PER_MSEC);  in ltc2952_poweroff_default()
165 	hrtimer_init(&data->timer_trigger, CLOCK_MONOTONIC, HRTIMER_MODE_REL);  in ltc2952_poweroff_default()
166 	data->timer_trigger.function = ltc2952_poweroff_timer_trigger;  in ltc2952_poweroff_default()
168 	hrtimer_init(&data->timer_wde, CLOCK_MONOTONIC, HRTIMER_MODE_REL);  in ltc2952_poweroff_default()
169 	data->timer_wde.function = ltc2952_poweroff_timer_wde;  in ltc2952_poweroff_default()
180 	if (!device_property_read_u32(&pdev->dev, "trigger-delay-ms",  in ltc2952_poweroff_init()
182 		data->trigger_delay = ktime_set(trigger_delay_ms / MSEC_PER_SEC,  in ltc2952_poweroff_init()
186 	data->gpio_watchdog = devm_gpiod_get(&pdev->dev, "watchdog",  in ltc2952_poweroff_init()
188 	if (IS_ERR(data->gpio_watchdog)) {  in ltc2952_poweroff_init()
189 		ret = PTR_ERR(data->gpio_watchdog);  in ltc2952_poweroff_init()
190 		dev_err(&pdev->dev, "unable to claim gpio \"watchdog\"\n");  in ltc2952_poweroff_init()
194 	data->gpio_kill = devm_gpiod_get(&pdev->dev, "kill", GPIOD_OUT_LOW);  in ltc2952_poweroff_init()
195 	if (IS_ERR(data->gpio_kill)) {  in ltc2952_poweroff_init()
196 		ret = PTR_ERR(data->gpio_kill);  in ltc2952_poweroff_init()
197 		dev_err(&pdev->dev, "unable to claim gpio \"kill\"\n");  in ltc2952_poweroff_init()
201 	data->gpio_trigger = devm_gpiod_get_optional(&pdev->dev, "trigger",  in ltc2952_poweroff_init()
203 	if (IS_ERR(data->gpio_trigger)) {  in ltc2952_poweroff_init()
209 		dev_err(&pdev->dev, "unable to claim gpio \"trigger\"\n");  in ltc2952_poweroff_init()
210 		data->gpio_trigger = NULL;  in ltc2952_poweroff_init()
213 	if (devm_request_irq(&pdev->dev, gpiod_to_irq(data->gpio_trigger),  in ltc2952_poweroff_init()
216 			     "ltc2952-poweroff",  in ltc2952_poweroff_init()
220 		 * - No trigger input was defined  in ltc2952_poweroff_init()
221 		 * - Claiming the GPIO failed  in ltc2952_poweroff_init()
222 		 * - We could not map to an IRQ  in ltc2952_poweroff_init()
223 		 * - We couldn't register an interrupt handler  in ltc2952_poweroff_init()
233 		if (data->gpio_trigger) {  in ltc2952_poweroff_init()
234 			dev_warn(&pdev->dev,  in ltc2952_poweroff_init()
236 			devm_gpiod_put(&pdev->dev, data->gpio_trigger);  in ltc2952_poweroff_init()
237 			data->gpio_trigger = NULL;  in ltc2952_poweroff_init()
239 		dev_info(&pdev->dev,  in ltc2952_poweroff_init()
240 			 "power down trigger input will not be used\n");  in ltc2952_poweroff_init()
252 	data->kernel_panic = true;  in ltc2952_poweroff_notify_panic()
262 		dev_err(&pdev->dev, "pm_power_off already registered");  in ltc2952_poweroff_probe()
263 		return -EBUSY;  in ltc2952_poweroff_probe()
266 	data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);  in ltc2952_poweroff_probe()
268 		return -ENOMEM;  in ltc2952_poweroff_probe()
270 	data->dev = &pdev->dev;  in ltc2952_poweroff_probe()
281 	data->panic_notifier.notifier_call = ltc2952_poweroff_notify_panic;  in ltc2952_poweroff_probe()
283 				       &data->panic_notifier);  in ltc2952_poweroff_probe()
284 	dev_info(&pdev->dev, "probe successful\n");  in ltc2952_poweroff_probe()
294 	hrtimer_cancel(&data->timer_trigger);  in ltc2952_poweroff_remove()
295 	hrtimer_cancel(&data->timer_wde);  in ltc2952_poweroff_remove()
297 					 &data->panic_notifier);  in ltc2952_poweroff_remove()
310 		.name = "ltc2952-poweroff",
318 MODULE_DESCRIPTION("LTC PowerPath power-off driver");