linux-kernel - Re: [PATCH] thermal: exynos: handle gate clock for misplaced TRIMINFO register

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Date:	Thu, 7 Nov 2013 20:41:57 +0530
From:	Naveen Krishna Ch <naveenkrishna.ch@...il.com>
To:	Tomasz Figa <t.figa@...sung.com>
Cc:	Naveen Krishna Chatradhi <ch.naveen@...sung.com>,
	linux-pm@...r.kernel.org, rui.zhang@...el.com,
	eduardo.valentin@...com,
	"linux-samsung-soc@...r.kernel.org" 
	<linux-samsung-soc@...r.kernel.org>, linux-kernel@...r.kernel.org,
	amit.daniel@...sung.com, Kukjin Kim <kgene.kim@...sung.com>,
	devicetree@...r.kernel.org, b.zolnierkie@...sung.com,
	cpgs@...sung.com
Subject: Re: [PATCH] thermal: exynos: handle gate clock for misplaced TRIMINFO register

On 7 November 2013 19:48, Tomasz Figa <t.figa@...sung.com> wrote:
> Hi Naveen,
>
> On Thursday 07 of November 2013 18:12:34 Naveen Krishna Chatradhi wrote:
>> On Exynos5420 the TMU(4) for GPU has a seperate clock enable bit from
>> the other TMU channels(0 ~ 3). Hence, accessing TRIMINFO for base_second
>> should be acompanied by enabling the respective clock.
>>
>> This patch which allow for a "clk_sec" clock to be specified in the
>> device-tree which will be ungated when accessing the TRIMINFO register.
>>
>> Signed-off-by: Andrew Bresticker <abrestic@...omium.org>
>> Signed-off-by: Naveen Krishna Chatradhi <ch.naveen@...sung.com>
>> ---
>>  drivers/thermal/samsung/exynos_tmu.c |   24 +++++++++++++++++++++++-
>>  1 file changed, 23 insertions(+), 1 deletion(-)
>
> This patch modifies the device binding, but fails to mention anything
> about the modification in respective documentation. Please do not do that.
Will make a note to update Documentation from now on.

>
> In addition, since the series adding support for Exynos 5420 has not been
> merged yet, I would rather make this patch a part of that series.
Will merge and upload the whole set, first thing tomorrow.
>
> Also please see my comment below.
>
>> diff --git a/drivers/thermal/samsung/exynos_tmu.c b/drivers/thermal/samsung/exynos_tmu.c
>> index b54825a..33edd1a 100644
>> --- a/drivers/thermal/samsung/exynos_tmu.c
>> +++ b/drivers/thermal/samsung/exynos_tmu.c
> [snip]
>> @@ -641,6 +650,15 @@ static int exynos_tmu_probe(struct platform_device *pdev)
>>       if (ret)
>>               return ret;
>>
>> +     data->clk_sec = devm_clk_get(&pdev->dev, "tmu_apbif_sec");
>> +     if (!IS_ERR(data->clk_sec)) {
>
> This code does not check if the clock was specified for TMU channels that
> require it, i.e. the driver will not fail if you don't specify this clock.
I thought of making it mandatory, And TMU on Exynos5440 may not need
second clock for accessing the second base. I Will confirm with the Exynso5440
specs and update accordingly.
>
> Instead, it would be better create a separate compatible value for such
> channels, like "samsung,exynos5420-tmu-broken-triminfo", for which this
> clock would be mandatory and for which, if this clock is not specified,
> the driver would fail.
Right

Sure Tomasz,
Creating a new compatible makes handling this case really simple

Thanks for reviewing.
>
> Best regards,
> Tomasz
>



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