[PATCH v4] power: reset: at91-reset: add sysfs interface to the power on reason
Miquel Raynal
miquel.raynal at bootlin.com
Wed Jul 12 08:58:53 PDT 2023
Hi Sebastian,
miquel.raynal at bootlin.com wrote on Tue, 20 Jun 2023 08:26:57 +0200:
> From: Kamel Bouhara <kamel.bouhara at bootlin.com>
>
> 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.
I just rebased this patch on top of -rc1, no conflict whatsoever, do
you need a resend or are you still considering this version?
> Signed-off-by: Kamel Bouhara <kamel.bouhara at bootlin.com>
> Acked-by: Nicolas Ferre <nicolas.ferre at microchip.com>
> [Miquel Raynal: Follow-up on Kamel's work, 4 years later]
> Signed-off-by: Miquel Raynal <miquel.raynal at bootlin.com>
Cheers,
Miquèl
> ---
>
> Changes in v4:
> * Patch 1/2 was merged.
> * Changed the "low-power condition" into a "brown-out reset" as
> suggested by Sebastian.
>
> Changes in v3:
> * Made the series bisectable.
> * Updated the date and kernel version for this new feature.
> * Changed a few definitions as discussed with Sebastian.
>
> Changes in v2:
> * Collected Nicolas' Acked-by
> * Dropped the Xtal frequency information (as this may change between
> platforms of course).
>
> .../testing/sysfs-platform-power-on-reason | 12 ++++++
> drivers/power/reset/at91-reset.c | 37 ++++++++++++++-----
> include/linux/power/power_on_reason.h | 19 ++++++++++
> 3 files changed, 58 insertions(+), 10 deletions(-)
> create mode 100644 Documentation/ABI/testing/sysfs-platform-power-on-reason
> create mode 100644 include/linux/power/power_on_reason.h
>
> diff --git a/Documentation/ABI/testing/sysfs-platform-power-on-reason b/Documentation/ABI/testing/sysfs-platform-power-on-reason
> new file mode 100644
> index 000000000000..c3b29dbc64bf
> --- /dev/null
> +++ b/Documentation/ABI/testing/sysfs-platform-power-on-reason
> @@ -0,0 +1,12 @@
> +What: /sys/devices/platform/.../power_on_reason
> +Date: June 2023
> +KernelVersion: 6.5
> +Contact: Kamel Bouhara <kamel.bouhara at 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.
> diff --git a/drivers/power/reset/at91-reset.c b/drivers/power/reset/at91-reset.c
> index d6884841a6dc..aa9b012d3d00 100644
> --- a/drivers/power/reset/at91-reset.c
> +++ b/drivers/power/reset/at91-reset.c
> @@ -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;
> diff --git a/include/linux/power/power_on_reason.h b/include/linux/power/power_on_reason.h
> new file mode 100644
> index 000000000000..95a1ec0c403c
> --- /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 at 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 */
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