linux-kernel - Re: [PATCH v2] rtc: tegra: Add ACPI support

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <f4defdc9-2cc0-45a0-a391-cb8678eb1b23@nvidia.com>
Date: Thu, 23 Oct 2025 12:14:13 +0530
From: Kartik Rajput <kkartik@...dia.com>
To: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Cc: alexandre.belloni@...tlin.com, thierry.reding@...il.com,
 jonathanh@...dia.com, linux-rtc@...r.kernel.org,
 linux-tegra@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] rtc: tegra: Add ACPI support

On 22/10/25 22:38, Andy Shevchenko wrote:
> External email: Use caution opening links or attachments
> 
> 
> On Wed, Oct 22, 2025 at 12:06:45PM +0530, Kartik Rajput wrote:
>> Add ACPI support for Tegra RTC, which is available on Tegra241 and
>> Tegra410. Both Tegra241 and Tegra410 use the same ACPI ID 'NVDA0280'.
>> The RTC clock is configured by UEFI before the kernel boots.
> 
> Thanks for an update, looks much better now!
> A comment below, though.
> 
> ...
> 
>> -     info->clk = devm_clk_get(&pdev->dev, NULL);
>> -     if (IS_ERR(info->clk))
>> -             return PTR_ERR(info->clk);
>> +     if (dev_of_node(&pdev->dev)) {
>> +             info->clk = devm_clk_get(&pdev->dev, NULL);
>> +             if (IS_ERR(info->clk))
>> +                     return PTR_ERR(info->clk);
>> +     }
>>
>>        ret = clk_prepare_enable(info->clk);
> 
> Since we still call CLK APIs unconditionally here, shouldn't be the whole
> approach just to move to _optional() CLK API?
> 
>          info->clk = devm_clk_get_optional(&pdev->dev, NULL);
> 
> I haven't checked the code below, but maybe even one can incorporate _enabled
> to this as well (in a separate change as it's not related to this patch
> directly).
> 

Hi Andy,

The reason I did not use the _optional API is because the clocks are required
for the device-tree. Therefore, it must fail if clocks are not provided on
device-tree boot.

Thanks,
Kartik


> --
> With Best Regards,
> Andy Shevchenko
> 
>