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Date: Fri, 29 Nov 2019 10:57:45 +0000
From: <Claudiu.Beznea@...rochip.com>
To: <kamel.bouhara@...tlin.com>, <sre@...nel.org>,
<Nicolas.Ferre@...rochip.com>, <alexandre.belloni@...tlin.com>,
<Ludovic.Desroches@...rochip.com>,
<linux-arm-kernel@...ts.infradead.org>
CC: <linux-kernel@...r.kernel.org>, <linux-pm@...r.kernel.org>,
<thomas.petazzoni@...tlin.com>
Subject: Re: [PATCH] power: reset: at91-reset: add sysfs interface to the
power on reason
Hi Kamel,
On 17.10.2019 15:40, Kamel Bouhara wrote:
> This patch export the power on reason through the sysfs interface and
> introduce some generic reset sources.
> Update the ABI documentation to list current power on sources.
>
> Signed-off-by: Kamel Bouhara <kamel.bouhara@...tlin.com>
> ---
> .../sysfs-devices-platform-power-on-reason | 14 ++++++
> drivers/power/reset/at91-reset.c | 44 +++++++++++++------
> include/linux/power/power_on_reason.h | 19 ++++++++
> 3 files changed, 64 insertions(+), 13 deletions(-)
> create mode 100644 Documentation/ABI/testing/sysfs-devices-platform-power-on-reason
> create mode 100644 include/linux/power/power_on_reason.h
>
> diff --git a/Documentation/ABI/testing/sysfs-devices-platform-power-on-reason b/Documentation/ABI/testing/sysfs-devices-platform-power-on-reason
> new file mode 100644
> index 000000000000..83daeb9b1aa2
> --- /dev/null
> +++ b/Documentation/ABI/testing/sysfs-devices-platform-power-on-reason
> @@ -0,0 +1,14 @@
> +What: /sys/devices/platform/.../power_on_reason
> +
> +Date: October 2019
> +KernelVersion: 5.4
> +Contact: Kamel Bouhara <kamel.bouhara@...tlin.com>
> +Description: This file shows system power on reason.
> + The possible sources are:
> + General System Power-ON, RTC wakeup, Watchdog timeout,
> + Software Reset, User pressed reset button,
> + CPU Clock failure, 32.768kHz Oscillator Failure,
> + Low power mode exit, Unknown.
> +
> + The file is read only.
> +
> diff --git a/drivers/power/reset/at91-reset.c b/drivers/power/reset/at91-reset.c
> index 44ca983a49a1..3cb2df40af37 100644
> --- a/drivers/power/reset/at91-reset.c
> +++ b/drivers/power/reset/at91-reset.c
> @@ -17,7 +17,7 @@
> #include <linux/of_address.h>
> #include <linux/platform_device.h>
> #include <linux/reboot.h>
> -
> +#include <linux/power/power_on_reason.h>
> #include <soc/at91/at91sam9_ddrsdr.h>
> #include <soc/at91/at91sam9_sdramc.h>
>
> @@ -146,42 +146,42 @@ static int samx7_restart(struct notifier_block *this, unsigned long mode,
> return NOTIFY_DONE;
> }
>
> -static void __init at91_reset_status(struct platform_device *pdev)
> +static const char *at91_reset_reason(struct platform_device *pdev)
> {
> const char *reason;
> u32 reg = readl(at91_rstc_base + AT91_RSTC_SR);
>
> switch ((reg & AT91_RSTC_RSTTYP) >> 8) {
> case RESET_TYPE_GENERAL:
> - reason = "general reset";
> + reason = POWER_ON_REASON_GENERAL;
> 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_USER;
> break;
> case RESET_TYPE_CPU_FAIL:
> - reason = "CPU clock failure detection";
> + reason = POWER_ON_REASON_CPU_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_LOW_POWER;
> break;
> default:
> - reason = "unknown reset";
> + reason = POWER_ON_REASON_UNKNOWN;
> break;
> }
>
> - dev_info(&pdev->dev, "Starting after %s\n", reason);
> + return reason;
> }
>
> static const struct of_device_id at91_ramc_of_match[] = {
> @@ -204,6 +204,17 @@ static struct notifier_block at91_restart_nb = {
> .priority = 192,
> };
>
> +static ssize_t power_on_reason_show(struct device *dev,
> + struct device_attribute *attr,
> + char *buf)
> +{
> + struct platform_device *pdev = to_platform_device(dev);
> +
> + return sprintf(buf, "%s\n", at91_reset_reason(pdev));
> +}
> +
> +static DEVICE_ATTR_RO(power_on_reason);
> +
> static int __init at91_reset_probe(struct platform_device *pdev)
> {
> const struct of_device_id *match;
> @@ -248,7 +259,14 @@ static int __init at91_reset_probe(struct platform_device *pdev)
> return ret;
> }
>
> - at91_reset_status(pdev);
> + 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 reset\n",
> + at91_reset_reason(pdev));
>
> return 0;
> }
> diff --git a/include/linux/power/power_on_reason.h b/include/linux/power/power_on_reason.h
> new file mode 100644
> index 000000000000..9978cc757427
> --- /dev/null
> +++ b/include/linux/power/power_on_reason.h
> @@ -0,0 +1,19 @@
> +/* SPDX-License-Identifier: GPL-2.0-only */
> +/*
> + * Author: Kamel Bouhra <kamel.bouhara@...tlin.com>
> + */
> +
> +#ifndef POWER_ON_REASON_H
> +#define POWER_ON_REASON_H
> +
> +#define POWER_ON_REASON_GENERAL "General"
> +#define POWER_ON_REASON_RTC "RTC wakeup"
> +#define POWER_ON_REASON_WATCHDOG "Watchdog timeout"
> +#define POWER_ON_REASON_SOFTWARE "Software"
> +#define POWER_ON_REASON_USER "User"
> +#define POWER_ON_REASON_CPU_FAIL "CPU Clock Failure"
> +#define POWER_ON_REASON_XTAL_FAIL "32.768k Crystal oscillator Failure"
> +#define POWER_ON_REASON_LOW_POWER "Low power exit"
> +#define POWER_ON_REASON_UNKNOWN "Unknown"
> +
> +#endif /* POWER_ON_REASON_H */
Is this new header necessary?
Thank you,
Claudiu Beznea
> --
> 2.23.0
>
>
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