From: Chanwoo Choi <cwchoi00@gmail.com>
To: Dmitry Osipenko <digetx@gmail.com>
Cc: linux-tegra@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-pm@vger.kernel.org,
Thierry Reding <thierry.reding@gmail.com>,
Jonathan Hunter <jonathanh@nvidia.com>,
Viresh Kumar <vireshk@kernel.org>, Nishanth Menon <nm@ti.com>,
MyungJoo Ham <myungjoo.ham@samsung.com>,
Stephen Boyd <sboyd@kernel.org>,
Kyungmin Park <kyungmin.park@samsung.com>,
Chanwoo Choi <cw00.choi@samsung.com>
Subject: Re: [PATCH v1 4/4] PM / devfreq: tegra30: Check whether clk_round_rate() returns zero rate
Date: Sun, 19 Sep 2021 18:43:41 +0900 [thread overview]
Message-ID: <4b5faca8-c0fc-e7bb-5a0b-c66714bc5f61@gmail.com> (raw)
In-Reply-To: <26d90b01-13d5-3bd8-da0a-b9ff61c7845a@gmail.com>
On 21. 9. 16. 오전 10:28, Dmitry Osipenko wrote:
> 15.09.2021 21:31, Chanwoo Choi пишет:
>> On 21. 9. 15. 오후 12:51, Chanwoo Choi wrote:
>>> Hi,
>>>
>>> On 21. 9. 13. 오전 3:44, Dmitry Osipenko wrote:
>>>> EMC clock is always-on and can't be zero. Check whether clk_round_rate()
>>>> returns zero rate and error out if it does. It can return zero if clock
>>>> tree isn't initialized properly.
>>>>
>>>> Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
>>>> ---
>>>> drivers/devfreq/tegra30-devfreq.c | 4 ++--
>>>> 1 file changed, 2 insertions(+), 2 deletions(-)
>>>>
>>>> diff --git a/drivers/devfreq/tegra30-devfreq.c
>>>> b/drivers/devfreq/tegra30-devfreq.c
>>>> index d83fdc2713ed..65ecf17a36f4 100644
>>>> --- a/drivers/devfreq/tegra30-devfreq.c
>>>> +++ b/drivers/devfreq/tegra30-devfreq.c
>>>> @@ -891,9 +891,9 @@ static int tegra_devfreq_probe(struct
>>>> platform_device *pdev)
>>>> return err;
>>>> rate = clk_round_rate(tegra->emc_clock, ULONG_MAX);
>>>> - if (rate < 0) {
>>>> + if (rate <= 0) {
>>>> dev_err(&pdev->dev, "Failed to round clock rate: %ld\n",
>>>> rate);
>>>> - return rate;
>>>> + return rate ?: -EINVAL;
>>
>> If rate is 0, It doesn't return and fall-through? even if print the
>> error message. 'return rate ?: -EINVAL;' style is strange for me
>> because it doesn't specify the 'return value' when rate is true.
>
> It's not clear to me what do you mean by "return and fall-through".
>
> It specifies the 'return value' when rate is true. It's a short form of
> "rate ? rate : -EINVAL".
I has not known this short form. Thanks for comment. I understand.
--
Best Regards,
Samsung Electronics
Chanwoo Choi
prev parent reply other threads:[~2021-09-19 9:44 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-12 18:44 [PATCH v1 0/4] Make probe() of Tegra devfreq driver completely resource-managed Dmitry Osipenko
2021-09-12 18:44 ` [PATCH v1 1/4] opp: Add more resource-managed variants of dev_pm_opp_of_add_table() Dmitry Osipenko
2021-09-12 18:44 ` [PATCH v1 2/4] PM / devfreq: Add devm_devfreq_add_governor() Dmitry Osipenko
2021-09-15 18:23 ` Chanwoo Choi
2021-09-16 1:30 ` Dmitry Osipenko
2021-09-15 18:37 ` Chanwoo Choi
2021-09-16 1:29 ` Dmitry Osipenko
2021-09-12 18:44 ` [PATCH v1 3/4] PM / devfreq: tegra30: Use resource-managed helpers Dmitry Osipenko
2021-09-12 18:44 ` [PATCH v1 4/4] PM / devfreq: tegra30: Check whether clk_round_rate() returns zero rate Dmitry Osipenko
2021-09-15 3:51 ` Chanwoo Choi
2021-09-15 18:31 ` Chanwoo Choi
2021-09-16 1:28 ` Dmitry Osipenko
2021-09-19 9:43 ` Chanwoo Choi [this message]
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