linux-kernel - Re: [PATCH 02/14] thermal: exynos: Propagate error value from tmu

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Message-ID: <4123d3bb-408f-b0c0-43c3-862e93f4907a@linaro.org>
Date:   Mon, 16 Apr 2018 14:54:01 +0200
From:   Daniel Lezcano <daniel.lezcano@...aro.org>
To:     Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>
Cc:     Eduardo Valentin <edubezval@...il.com>,
        Zhang Rui <rui.zhang@...el.com>,
        Krzysztof Kozlowski <krzk@...nel.org>,
        Kukjin Kim <kgene@...nel.org>,
        linux-samsung-soc@...r.kernel.org, linux-pm@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        Marek Szyprowski <m.szyprowski@...sung.com>
Subject: Re: [PATCH 02/14] thermal: exynos: Propagate error value from
 tmu_read()

On 16/04/2018 14:49, Bartlomiej Zolnierkiewicz wrote:
> On Monday, April 16, 2018 02:41:48 PM Daniel Lezcano wrote:
>> On 16/04/2018 14:35, Bartlomiej Zolnierkiewicz wrote:
>>> On Monday, April 16, 2018 02:16:56 PM Daniel Lezcano wrote:
>>>> On 16/04/2018 12:11, Bartlomiej Zolnierkiewicz wrote:
>>>>> From: Marek Szyprowski <m.szyprowski@...sung.com>
>>>>>
>>>>> tmu_read() in case of Exynos4210 might return error for out of bound
>>>>> values. Current code ignores such value, what leads to reporting critical
>>>>> temperature value. Add proper error code propagation to exynos_get_temp()
>>>>> function.
>>>>
>>>> For me the comment in the function exynos4210_tmu_read
>>>>
>>>> /* "temp_code" should range between 75 and 175 */
>>>>
>>>> ... is strange. I would double check this assertion before dealing with
>>>> the error value.
>>>
>>> static int exynos4210_tmu_read(struct exynos_tmu_data *data)
>>> {
>>> 	int ret = readb(data->base + EXYNOS_TMU_REG_CURRENT_TEMP);
>>>
>>> 	/* "temp_code" should range between 75 and 175 */
>>> 	return (ret < 75 || ret > 175) ? -ENODATA : ret;
>>> }
>>>
>>
>> But I don't get why it *should* ?
> 
> Because of hardware design.
> 
>> Shouldn't be the same with the 4412, it seems having the same sensor, no?
> 
> Probably same limitations apply to all SoCs (Exynos4412 has very similar
> sensor) but the driver currently lacks the needed checks for them (it is
> on TODO but other things have higher priority).


I understand. Why the other boards are not reporting a critical value?




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