linux-kernel - Re: BD71847 clk driver disables clk-32k-out causing RTC/WDT failure

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Message-ID: <2ab24cc4-4aa2-d364-9b29-55f5d6b23626@denx.de>
Date:   Thu, 8 Sep 2022 18:55:45 +0200
From:   Marek Vasut <marex@...x.de>
To:     Tim Harvey <tharvey@...eworks.com>,
        Matti Vaittinen <mazziesaccount@...il.com>
Cc:     linux-clk <linux-clk@...r.kernel.org>,
        open list <linux-kernel@...r.kernel.org>,
        Fabio Estevam <festevam@...il.com>,
        Shawn Guo <shawnguo@...nel.org>,
        NXP Linux Team <linux-imx@....com>,
        Stephen Boyd <sboyd@...nel.org>,
        Michael Turquette <mturquette@...libre.com>
Subject: Re: BD71847 clk driver disables clk-32k-out causing RTC/WDT failure

On 9/8/22 18:00, Tim Harvey wrote:
> On Thu, Sep 1, 2022 at 9:14 PM Matti Vaittinen <mazziesaccount@...il.com> wrote:
>>
>> Hi Tim,
>>
>> On 9/2/22 01:23, Tim Harvey wrote:
>>> Greetings,
>>>
>>> I've found that the bd71847 clk driver (CONFIG_COMMON_CLK_BD718XX
>>> drivers/clk/clk-bd718x7.c) disables clk-32k-out (the BD71847 C32K_OUT
>>> pin) which is connected IMX8MM RTC_XTALI which ends up disabling the
>>> IMX RTC as well as the IMX WDOG functionality.
>>
>> //snip
>>
>>> This happens via clk_unprepare_unused() as nothing is flagging the
>>> clk-32k-out as being used. What should be added to the device-tree to
>>> signify that this clk is indeed necessary and should not be disabled?
>>
>> I have seen following proposal from Marek Vasut:
>>
>> https://lore.kernel.org/all/20220517235919.200375-1-marex@denx.de/T/#m52d6d0831bf43d5f293e35cb27f3021f278d0564
>>
>> I am not sure if the discussion is completed though. I guess it was
>> agreed this was needed/usefull and maybe the remaining thing to decide
>> was just the property naming.
>>
>> Best Regards
>>          -- Matti
>>
> 
> Thanks Matti,
> 
> Marek - has there been any progress on determining how best to keep
> certain clocks from being disabled?

No. You can read the discussion above.