Commit d40befed authored by Kamel Bouhara's avatar Kamel Bouhara Committed by Sebastian Reichel
Browse files

power: reset: at91-reset: add sysfs interface to the power on reason 



Introduce a list of generic reset sources and use them to export the
power on reason through sysfs. Update the ABI documentation to describe
this new interface.

Signed-off-by: default avatarKamel Bouhara <kamel.bouhara@bootlin.com>
Acked-by: default avatarNicolas Ferre <nicolas.ferre@microchip.com>
[Miquel Raynal: Follow-up on Kamel's work, 4 years later]
Signed-off-by: default avatarMiquel Raynal <miquel.raynal@bootlin.com>
Signed-off-by: default avatarSebastian Reichel <sebastian.reichel@collabora.com>
parent 7b9fc309

Documentation/ABI/testing/sysfs-platform-power-on-reason

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+12 −0
Original line number Diff line number Diff line 
What:		/sys/devices/platform/.../power_on_reason

Date:		June 2023

KernelVersion:	6.5

Contact:	Kamel Bouhara <kamel.bouhara@bootlin.com>

Description:	Shows system power on reason. The following strings/reasons can

		be read (the list can be extended):

		"regular power-up", "RTC wakeup", "watchdog timeout",

		"software reset", "reset button action", "CPU clock failure",

		"crystal oscillator failure", "brown-out reset",

		"unknown reason".



		The file is read only.

drivers/power/reset/at91-reset.c

+27 −10
Original line number Diff line number Diff line
@@ -18,6 +18,7 @@ 
#include <linux/platform_device.h>

#include <linux/reboot.h>

#include <linux/reset-controller.h>

#include <linux/power/power_on_reason.h>



#include <soc/at91/at91sam9_ddrsdr.h>

#include <soc/at91/at91sam9_sdramc.h>
@@ -149,44 +150,54 @@ static int at91_reset(struct notifier_block *this, unsigned long mode, 
	return NOTIFY_DONE;

}



static const char * __init at91_reset_reason(struct at91_reset *reset)

static const char *at91_reset_reason(struct at91_reset *reset)

{

	u32 reg = readl(reset->rstc_base + AT91_RSTC_SR);

	const char *reason;



	switch ((reg & AT91_RSTC_RSTTYP) >> 8) {

	case RESET_TYPE_GENERAL:

		reason = "general reset";

		reason = POWER_ON_REASON_REGULAR;

		break;

	case RESET_TYPE_WAKEUP:

		reason = "wakeup";

		reason = POWER_ON_REASON_RTC;

		break;

	case RESET_TYPE_WATCHDOG:

		reason = "watchdog reset";

		reason = POWER_ON_REASON_WATCHDOG;

		break;

	case RESET_TYPE_SOFTWARE:

		reason = "software reset";

		reason = POWER_ON_REASON_SOFTWARE;

		break;

	case RESET_TYPE_USER:

		reason = "user reset";

		reason = POWER_ON_REASON_RST_BTN;

		break;

	case RESET_TYPE_CPU_FAIL:

		reason = "CPU clock failure detection";

		reason = POWER_ON_REASON_CPU_CLK_FAIL;

		break;

	case RESET_TYPE_XTAL_FAIL:

		reason = "32.768 kHz crystal failure detection";

		reason = POWER_ON_REASON_XTAL_FAIL;

		break;

	case RESET_TYPE_ULP2:

		reason = "ULP2 reset";

		reason = POWER_ON_REASON_BROWN_OUT;

		break;

	default:

		reason = "unknown reset";

		reason = POWER_ON_REASON_UNKNOWN;

		break;

	}



	return reason;

}



static ssize_t power_on_reason_show(struct device *dev,

				    struct device_attribute *attr, char *buf)

{

	struct platform_device *pdev = to_platform_device(dev);

	struct at91_reset *reset = platform_get_drvdata(pdev);



	return sprintf(buf, "%s\n", at91_reset_reason(reset));

}

static DEVICE_ATTR_RO(power_on_reason);



static const struct of_device_id at91_ramc_of_match[] = {

	{

		.compatible = "atmel,at91sam9260-sdramc",
@@ -391,6 +402,12 @@ static int __init at91_reset_probe(struct platform_device *pdev) 
	if (ret)

		goto disable_clk;



	ret = device_create_file(&pdev->dev, &dev_attr_power_on_reason);

	if (ret) {

		dev_err(&pdev->dev, "Could not create sysfs entry\n");

		return ret;

	}



	dev_info(&pdev->dev, "Starting after %s\n", at91_reset_reason(reset));



	return 0;

include/linux/power/power_on_reason.h

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Original line number Diff line number Diff line 
/* SPDX-License-Identifier: GPL-2.0-only */

/*

 * Author: Kamel Bouhra <kamel.bouhara@bootlin.com>

 */



#ifndef POWER_ON_REASON_H

#define POWER_ON_REASON_H



#define POWER_ON_REASON_REGULAR "regular power-up"

#define POWER_ON_REASON_RTC "RTC wakeup"

#define POWER_ON_REASON_WATCHDOG "watchdog timeout"

#define POWER_ON_REASON_SOFTWARE "software reset"

#define POWER_ON_REASON_RST_BTN "reset button action"

#define POWER_ON_REASON_CPU_CLK_FAIL "CPU clock failure"

#define POWER_ON_REASON_XTAL_FAIL "crystal oscillator failure"

#define POWER_ON_REASON_BROWN_OUT "brown-out reset"

#define POWER_ON_REASON_UNKNOWN "unknown reason"



#endif /* POWER_ON_REASON_H */