From: claudiu beznea <claudiu.beznea@tuxon.dev>
To: Guenter Roeck <linux@roeck-us.net>,
wim@linux-watchdog.org, robh+dt@kernel.org,
krzysztof.kozlowski+dt@linaro.org, conor+dt@kernel.org,
geert+renesas@glider.be, magnus.damm@gmail.com,
mturquette@baylibre.com, sboyd@kernel.org,
p.zabel@pengutronix.de, biju.das.jz@bp.renesas.com
Cc: linux-watchdog@vger.kernel.org, devicetree@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-renesas-soc@vger.kernel.org,
linux-clk@vger.kernel.org,
Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
Subject: Re: [PATCH 03/10] watchdog: rzg2l_wdt: Check return status of pm_runtime_put()
Date: Tue, 23 Jan 2024 09:02:35 +0200 [thread overview]
Message-ID: <92db308f-075c-4799-9777-5bc14438ce68@tuxon.dev> (raw)
In-Reply-To: <c857cdd4-459b-41ae-b4bb-0da45e461335@roeck-us.net>
On 22.01.2024 19:31, Guenter Roeck wrote:
> On 1/22/24 03:11, Claudiu wrote:
>> From: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
>>
>> pm_runtime_put() may return an error code. Check its return status.
>>
>> Fixes: 2cbc5cd0b55f ("watchdog: Add Watchdog Timer driver for RZ/G2L")
>> Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
>> ---
>> drivers/watchdog/rzg2l_wdt.c | 6 +++++-
>> 1 file changed, 5 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/watchdog/rzg2l_wdt.c b/drivers/watchdog/rzg2l_wdt.c
>> index 4ab9e7c5e771..0554965027cd 100644
>> --- a/drivers/watchdog/rzg2l_wdt.c
>> +++ b/drivers/watchdog/rzg2l_wdt.c
>> @@ -144,9 +144,13 @@ static int rzg2l_wdt_start(struct watchdog_device
>> *wdev)
>> static int rzg2l_wdt_stop(struct watchdog_device *wdev)
>> {
>> struct rzg2l_wdt_priv *priv = watchdog_get_drvdata(wdev);
>> + int ret;
>> rzg2l_wdt_reset(priv);
>> - pm_runtime_put(wdev->parent);
>> +
>> + ret = pm_runtime_put(wdev->parent);
>> + if (ret < 0)
>> + return ret;
>> return 0;
>> }
>
> A simple
> return pm_runtime_put();
> might do.
pm_runtime_put() may return 1 if the device is already suspended though
this call trace:
pm_runtime_put() ->
__pm_runtime_idle() ->
rpm_idle() ->
rpm_suspend() ->
rpm_check_suspend_allowed() [1]
That return value is not considered error thus I wanted to consider it
here, too.
[1]
https://elixir.bootlin.com/linux/latest/source/drivers/base/power/runtime.c#L278
>
> However, one question: Given that pm_runtime_put() returns -ENOSYS if
> CONFIG_PM is disabled, that means the driver will depend on CONFIG_PM=y.
Indeed, the driver depends on CONFIG_PM=y for proper working. It is for
devices selecting ARCH_RZG2L and RZ/V2M (ARM64 based uarch) which select
CONFIG_PM=y:
https://elixir.bootlin.com/linux/latest/source/drivers/soc/renesas/Kconfig#L45
The driver is written with CONFIG_PM=y dependency in mind (e.g. the clocks
are enabled though runtime PM APIs).
> Assuming this is intentional, would it make sense to explicitly declare
> that dependency in Kconfig ? It doesn't seem to make any sense to build
> the driver if it won't work anyway.
The dependency exists there for ARCH_RZG2L and RZ/V2M devices but not
directly and it is not strict (in the sense that we allow to build the
driver w/o CONFIG_PM (I think this is good to check build on different
configurations, the COMPILE_TEST is there anyway in [1]) ). E.g.:
RENESAS_RZG2LWDT depends on ARCH_RENESAS [1]
ARCH_RENESAS is the ARMv8 uarch flag [2]
SOC_RENESAS is set if ARCH_RENESAS [3]
ARCH_RZG2L is visible only if SOC_RENESAS [4]
ARCH_RZG2L selects PM [5]
RZ/V2M selects PM [6]
Please let me know what do you think about it?
Thank you,
Claudiu Beznea
[1]
https://elixir.bootlin.com/linux/latest/source/drivers/watchdog/Kconfig#L913
[2]
https://elixir.bootlin.com/linux/latest/source/arch/arm64/Kconfig.platforms#L273
[3]
https://elixir.bootlin.com/linux/latest/source/drivers/soc/renesas/Kconfig#L2
[4]
https://elixir.bootlin.com/linux/latest/source/drivers/soc/renesas/Kconfig#L9
[5]
https://elixir.bootlin.com/linux/latest/source/drivers/soc/renesas/Kconfig#L45
[6]
https://elixir.bootlin.com/linux/latest/source/drivers/soc/renesas/Kconfig#L328
>
> Thanks,
> Guenter
>
next prev parent reply other threads:[~2024-01-23 7:02 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-01-22 11:11 [PATCH 00/10] watchdog: rzg2l_wdt: Add support for RZ/G3S Claudiu
2024-01-22 11:11 ` [PATCH 01/10] clk: renesas: r9a08g045: Add clock and reset support for watchdog Claudiu
2024-01-30 16:38 ` Geert Uytterhoeven
2024-01-22 11:11 ` [PATCH 02/10] watchdog: rzg2l_wdt: Use pm_runtime_resume_and_get() Claudiu
2024-01-30 16:43 ` Geert Uytterhoeven
2024-01-22 11:11 ` [PATCH 03/10] watchdog: rzg2l_wdt: Check return status of pm_runtime_put() Claudiu
2024-01-22 17:31 ` Guenter Roeck
2024-01-23 7:02 ` claudiu beznea [this message]
2024-01-23 10:00 ` Guenter Roeck
2024-01-22 11:11 ` [PATCH 04/10] watchdog: rzg2l_wdt: Remove reset de-assert on probe/stop Claudiu
2024-01-22 11:11 ` [PATCH 05/10] watchdog: rzg2l_wdt: Remove comparison with zero Claudiu
2024-01-22 11:11 ` [PATCH 06/10] watchdog: rzg2l_wdt: Rely on the reset driver for doing proper reset Claudiu
2024-01-22 11:11 ` [PATCH 07/10] watchdog: rzg2l_wdt: Add suspend/resume support Claudiu
2024-01-22 17:39 ` Guenter Roeck
2024-01-22 21:05 ` Jerry Hoemann
2024-01-22 22:00 ` Guenter Roeck
2024-01-23 7:13 ` claudiu beznea
2024-01-23 10:09 ` Guenter Roeck
2024-01-23 11:40 ` claudiu beznea
2024-01-22 11:11 ` [PATCH 08/10] dt-bindings: watchdog: renesas,wdt: Document RZ/G3S support Claudiu
2024-01-22 17:12 ` Conor Dooley
2024-01-30 16:48 ` Geert Uytterhoeven
2024-01-22 11:11 ` [PATCH 09/10] arm64: dts: renesas: r9a08g045: Add watchdog node Claudiu
2024-01-30 16:51 ` Geert Uytterhoeven
2024-01-22 11:11 ` [PATCH 10/10] arm64: dts: renesas: rzg3s-smarc-som: Enable the watchdog interface Claudiu
2024-01-30 16:51 ` Geert Uytterhoeven
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