linux-kernel - Re: [RFC PATCH 3/7] regulator: IRQ based event/error notification helpers

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Message-ID: <6355af19b137fe25d55c33f813b05ba43e2cd41e.camel@fi.rohmeurope.com>
Date:   Fri, 12 Feb 2021 09:33:44 +0000
From:   "Vaittinen, Matti" <Matti.Vaittinen@...rohmeurope.com>
To:     "Vaittinen, Matti" <Matti.Vaittinen@...rohmeurope.com>
CC:     "agross@...nel.org" <agross@...nel.org>,
        "tj@...nel.org" <tj@...nel.org>,
        "jiangshanlai@...il.com" <jiangshanlai@...il.com>,
        "broonie@...nel.org" <broonie@...nel.org>,
        "devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
        linux-power <linux-power@...rohmeurope.com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-renesas-soc@...r.kernel.org" 
        <linux-renesas-soc@...r.kernel.org>,
        "linux-arm-msm@...r.kernel.org" <linux-arm-msm@...r.kernel.org>,
        "bjorn.andersson@...aro.org" <bjorn.andersson@...aro.org>,
        "lgirdwood@...il.com" <lgirdwood@...il.com>,
        "robh+dt@...nel.org" <robh+dt@...nel.org>
Subject: Re: [RFC PATCH 3/7] regulator: IRQ based event/error notification
 helpers

On Thu, 2021-02-11 at 14:35 +0200, Matti Vaittinen wrote:
> Provide helper function for IC's implementing regulator notifications
> when an IRQ fires. The helper also works for IRQs which can not be
> acked.
> Helper can be set to disable the IRQ at handler and then re-enabling
> it
> on delayed work later. The helper also adds
> regulator_get_error_flags()
> errors in cache for the duration of IRQ disabling.
> 
> Signed-off-by: Matti Vaittinen <matti.vaittinen@...rohmeurope.com>
> ---
> 
> This patch has gone through only a very limited amount of testing.
> All
> reviews / suggestions / testing is highly appreciated.
> 

/* SNIP */

> +
> +static void dev_delayed_work_drop(struct device *dev, void *res)
> +{
> +	cancel_delayed_work_sync(*(struct delayed_work **)res);
> +}
> +
> +int dev_delayed_work_autocancel(struct device *dev, struct
> delayed_work *w,
> +				void (*worker)(struct work_struct
> *work))
> +{
> +	struct delayed_work **ptr;
> +
> +	ptr = devres_alloc(dev_delayed_work_drop, sizeof(*ptr),
> GFP_KERNEL);
> +	if (!ptr)
> +		return -ENOMEM;
> +
> +	INIT_DELAYED_WORK(w, worker);
> +	*ptr = w;
> +	devres_add(dev, ptr);
> +
> +	return 0;
> +}
> +

I got mail from build-bot. Sparse warning. Bot suggested staticizing
the dev_delayed_work_autocancel(). I should've been more careful.

It how ever made me wonder if this would actually be worth exporting?

There seems to be few drivers which need delayed wq and which implement
.remove() just to call the cancel_delayed_work_sync().

I think this might help cleaning up those(?) Or am I completely off
here?

I just did:
git grep -A15 remove |grep -B10 -A10 cancel_delayed_work_sync

in drivers directory and spotted couple of candidates like
watchdog/retu_wdt.c (should also use devm_watchdog_register_device)
regulator/qcom_spmi-regulator.c
power/supply/sbs-charger.c
power/supply/sbs-battery.c
power/supply/ltc2941-battery-gauge.c
...

And no. I am not offering to go through _all_ drivers, but I guess I
could go through at least few of them :)

And sorry for noise if this has been suggested and rejected before - I
didn't spot something like this from mail lists. (Maybe I am missing
something?)

Best Regards
   Matti Vaittinen


--
Matti Vaittinen, Linux device drivers
ROHM Semiconductors, Finland
SWDC
Kiviharjunlenkki 1E
90220 OULU
FINLAND

~~~ "I don't think so," said Rene Descartes. Just then he vanished ~~~

Simon says - in Latin please.
"non cogito me" dixit Rene Descarte, deinde evanescavit

(Thanks for the translation Simon)