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Fri, 29 Nov 2019 15:40:20 +0000 (UTC) Date: Fri, 29 Nov 2019 16:40:16 +0100 From: Alexandre Belloni To: Eugen.Hristev@microchip.com Cc: Claudiu.Beznea@microchip.com, kamel.bouhara@bootlin.com, linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org, sre@kernel.org, Ludovic.Desroches@microchip.com, thomas.petazzoni@bootlin.com, linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH] power: reset: at91-reset: add sysfs interface to the power on reason Message-ID: <20191129154016.GZ299836@piout.net> References: <20191017124058.19300-1-kamel.bouhara@bootlin.com> <034c9d01-633a-eeaa-f61f-d185be7227f2@microchip.com> <20191129110253.GX299836@piout.net> <00f4e9a2-f6bd-9242-cafd-9c0c4f4dc619@microchip.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <00f4e9a2-f6bd-9242-cafd-9c0c4f4dc619@microchip.com> User-Agent: Mutt/1.12.1 (2019-06-15) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 29/11/2019 11:15:18+0000, Eugen.Hristev@microchip.com wrote: > > > On 29.11.2019 13:02, Alexandre Belloni wrote: > > > On 29/11/2019 10:57:45+0000, Claudiu.Beznea@microchip.com wrote: > >> 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 > >>> --- > >>> .../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 > >>> +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 > >>> #include > >>> #include > >>> - > >>> +#include > >>> #include > >>> #include > >>> > >>> @@ -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 > >>> + */ > >>> + > >>> +#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" > > Hi, > > Looks rather odd to have a hardcoded crystal value inside a generic header. > Also how is REASON_CPU_FAIL related to CPU Clock ? > Yes, I also think having the xtal rate is a bit too specific. -- Alexandre Belloni, Bootlin Embedded Linux and Kernel engineering https://bootlin.com