diff mbox series

[v4,1/2] power: reset: at91-reset: export reset reason through sysfs

Message ID 20191220100740.117897-1-kamel.bouhara@bootlin.com (mailing list archive)
State New, archived
Headers show
Series [v4,1/2] power: reset: at91-reset: export reset reason through sysfs | expand

Commit Message

Kamel BOUHARA Dec. 20, 2019, 10:07 a.m. UTC 
Export the reset reason through a sysfs file so it can be exploited by
user space application.

 $ cat /sys/devices/platform/ahb/ahb:apb/f8048000.rstc/power_on_reason
 RTC wakeup

Signed-off-by: Kamel Bouhara <kamel.bouhara@bootlin.com>
Acked-by: Nicolas Ferre <nicolas.ferre@microchip.com>
---
Changes in v2
=============
	- Be less specific on the crystal oscillator value
	- Add an Acked-by
Changes in v3
=============
	- Really be less specific on the crystal oscillator value
Changes in v4
=============
	- Rebase to 5.5-rc2
	- Remove remaining crystal specific value in documentation
	- Split the patch for the sake of clarity
	- Match the documentation with the actual header defines

 drivers/power/reset/at91-reset.c | 44 ++++++++++++++++++++++----------
 1 file changed, 31 insertions(+), 13 deletions(-)

--
2.24.0
diff mbox series

Patch

diff --git a/drivers/power/reset/at91-reset.c b/drivers/power/reset/at91-reset.c
index d94e3267c3b6..c1625572f07c 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>

@@ -144,42 +144,42 @@  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[] = {
@@ -202,6 +202,17 @@  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;
@@ -246,7 +257,14 @@  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;
 }