From: Michael Walle <michael@walle.cc>
To: "Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>
Cc: Lee Jones <lee.jones@linaro.org>,
Thierry Reding <thierry.reding@gmail.com>,
linux-pwm@vger.kernel.org, kernel@pengutronix.de
Subject: Re: [PATCH] pwm: sl28cpld: fix getting driver data in pwm callbacks
Date: Mon, 30 Nov 2020 09:17:52 +0100 [thread overview]
Message-ID: <3becef43bd9119c624cf6c3c8ee5b472@walle.cc> (raw)
In-Reply-To: <20201124212432.3117322-1-u.kleine-koenig@pengutronix.de>
Am 2020-11-24 22:24, schrieb Uwe Kleine-König:
> Currently .get_state() and .apply() use dev_get_drvdata() on the struct
> device related to the pwm chip. This only works after .probe() called
> platform_set_drvdata() which in this driver happens only after
> pwmchip_add() and so comes possibly too late.
>
> Instead of setting the driver data earlier use the traditional
> container_of approach as this way the driver data is conceptually and
> computational nearer.
>
> Fixes: 9db33d221efc ("pwm: Add support for sl28cpld PWM controller")
> Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
> ---
> Hello,
>
> in v4 of the driver Michael still used container_of and then changed to
> use dev_get_drvdata() as Lee suggested. I didn't notice this
> suggestion,
> otherwise I would have expressed my variance about this already
> earlier.
>
> I noticed this problem because Michael contacted me via irc and showed
> me the resulting oops, so I think applying this before 5.10 would be
> good. It's not entirely clear to me why .get_state() is called that
> early in his case, but the theory is clear: The callbacks can be called
> as soon as pwmchip_add() is called.
>
> Best regards
> Uwe
Ping. Would be nice if this makes it into v5.10.
-michael
next prev parent reply other threads:[~2020-11-30 8:18 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-24 21:24 Uwe Kleine-König
2020-11-24 22:22 ` Michael Walle
2020-11-25 6:48 ` Uwe Kleine-König
2020-11-30 8:17 ` Michael Walle [this message]
2020-11-30 14:58 ` Uwe Kleine-König
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