diff mbox series

[v4] power: reset: at91-reset: add sysfs interface to the power on reason

Message ID 20230620062657.3127468-1-miquel.raynal@bootlin.com (mailing list archive)
State New, archived
Headers show
Series [v4] power: reset: at91-reset: add sysfs interface to the power on reason | expand

Commit Message

Miquel Raynal June 20, 2023, 6:26 a.m. UTC 
From: Kamel Bouhara <kamel.bouhara@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.

Signed-off-by: Kamel Bouhara <kamel.bouhara@bootlin.com>
Acked-by: Nicolas Ferre <nicolas.ferre@microchip.com>
[Miquel Raynal: Follow-up on Kamel's work, 4 years later]
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
---

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

Comments

Miquel Raynal July 12, 2023, 3:58 p.m. UTC | #1 
Hi Sebastian,

miquel.raynal@bootlin.com wrote on Tue, 20 Jun 2023 08:26:57 +0200:

> From: Kamel Bouhara <kamel.bouhara@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@bootlin.com>
> Acked-by: Nicolas Ferre <nicolas.ferre@microchip.com>
> [Miquel Raynal: Follow-up on Kamel's work, 4 years later]
> Signed-off-by: Miquel Raynal <miquel.raynal@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@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@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 */
Sebastian Reichel July 19, 2023, 9:23 p.m. UTC | #2 
Hi,

On Wed, Jul 12, 2023 at 05:58:53PM +0200, Miquel Raynal wrote:
> > From: Kamel Bouhara <kamel.bouhara@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@bootlin.com>
> > Acked-by: Nicolas Ferre <nicolas.ferre@microchip.com>
> > [Miquel Raynal: Follow-up on Kamel's work, 4 years later]
> > Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>

Thanks, queued.

-- Sebastian
diff mbox series

Patch

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@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@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 */