linux-kernel - Re: [PATCH] opp: Don't ignore clk

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Message-ID: <20210129174608.owianuy6yj5m6fgl@vireshk-i7>
Date:   Fri, 29 Jan 2021 23:16:08 +0530
From:   Viresh Kumar <viresh.kumar@...aro.org>
To:     Dmitry Osipenko <digetx@...il.com>
Cc:     Viresh Kumar <vireshk@...nel.org>, Nishanth Menon <nm@...com>,
        Stephen Boyd <sboyd@...nel.org>, linux-pm@...r.kernel.org,
        Vincent Guittot <vincent.guittot@...aro.org>,
        Rafael Wysocki <rjw@...ysocki.net>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] opp: Don't ignore clk_get() errors other than -ENODEV

On 29-01-21, 18:23, Dmitry Osipenko wrote:
> 29.01.2021 13:51, Viresh Kumar пишет:
> > Not all devices that need to use OPP core need to have clocks, a missing
> > clock is fine in which case -ENODEV shall be returned by clk_get().
> > 
> > Anything else is an error and must be handled properly.
> > 
> > Reported-by: Dmitry Osipenko <digetx@...il.com>
> > Signed-off-by: Viresh Kumar <viresh.kumar@...aro.org>
> > ---
> > Stephen, is the understanding correct that -ENODEV is the only error
> > returned for missing clocks ?
> > 
> > Dmitry: I hope this is on the lines of what you were looking for ?
> 
> Viresh, thank you! This is not what I was looking for because clk core
> doesn't return -ENODEV for a missing clock, but -ENOENT. The ENODEV
> certainly should break drivers.

My bad.
 
> I was looking for this:
> 
> diff --git a/drivers/opp/core.c b/drivers/opp/core.c
> index 0305861fee1b..3dd9cdbc0e75 100644
> --- a/drivers/opp/core.c
> +++ b/drivers/opp/core.c
> @@ -1264,7 +1264,7 @@ static struct opp_table
> *_update_opp_table_clk(struct device *dev,
>  	if (IS_ERR(opp_table->clk)) {
>  		int ret = PTR_ERR(opp_table->clk);
> 
> -		if (ret == -EPROBE_DEFER) {
> +		if (ret != -ENOENT) {
>  			dev_pm_opp_put_opp_table(opp_table);
>  			return ERR_PTR(ret);
>  		}

You should be looking for this instead, isn't it ?

diff --git a/drivers/opp/core.c b/drivers/opp/core.c
index 049d45e70807..4bfcbe5b57af 100644
--- a/drivers/opp/core.c
+++ b/drivers/opp/core.c
@@ -1268,7 +1268,7 @@ static struct opp_table *_update_opp_table_clk(struct device *dev,
        if (!ret)
                return opp_table;
 
-       if (ret == -ENODEV) {
+       if (ret == -ENOENT) {
                dev_dbg(dev, "%s: Couldn't find clock: %d\n", __func__, ret);
                return opp_table;
        }


-- 
viresh