linux-kernel - Re: [PATCH] iio: adc: exynos_adc: Control special clock of ADC to support Exynos3250 ADC

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Date:	Sat, 12 Apr 2014 08:49:44 +0100
From:	Jonathan Cameron <jic23@...nel.org>
To:	최찬우 <cwchoi00@...il.com>,
	Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>
CC:	Chanwoo Choi <cw00.choi@...sung.com>, ch.naveen@...sung.com,
	Kukjin Kim <kgene.kim@...sung.com>, linux-iio@...r.kernel.org,
	linux-samsung-soc <linux-samsung-soc@...r.kernel.org>,
	linux-kernel <linux-kernel@...r.kernel.org>,
	linux-arm-kernel <linux-arm-kernel@...ts.infradead.org>,
	Kyungmin Park <kyungmin.park@...sung.com>
Subject: Re: [PATCH] iio: adc: exynos_adc: Control special clock of ADC to support Exynos3250 ADC



On April 11, 2014 11:45:42 PM GMT+01:00, "최찬우" <cwchoi00@...il.com> wrote:
>Hi Bartlomiej,
>
>On Fri, Apr 11, 2014 at 6:41 PM, Bartlomiej Zolnierkiewicz
><b.zolnierkie@...sung.com> wrote:
>>
>> Hi,
>>
>> On Friday, April 11, 2014 11:00:40 AM Chanwoo Choi wrote:
>>> This patch control special clock for ADC in Exynos series's FSYS
>block.
>>
>> s/control/controls/
>
>I'll fix it.
>
>>
>>> If special clock of ADC is registerd on clock list of common clk
>framework,
>>> Exynos ADC drvier have to control this clock.
>>
>> s/drvier/driver/
>
>I'll fix it.
>
>>
>>> Exynos3250/Exynos4/Exynos5 has 'adc' clock as following:
>>> - 'adc' clock: bus clock for ADC
>>>
>>> Exynos3250 has additional 'sclk_tsadc' clock as following:
>>> - 'sclk_tsadc' clock: special clock for ADC which provide clock to
>internal ADC
>>>
>>> Exynos 4210/4212/4412 and Exynos5250/5420 has not included
>'sclk_tsadc' clock
>>> in FSYS_BLK. But, Exynos3250 based on Cortex-A7 has only included
>'sclk_tsadc'
>>> clock in FSYS_BLK.
>>>
>>> Cc: Jonathan Cameron <jic23@...nel.org>
>>> Cc: Kukjin Kim <kgene.kim@...sung.com>
>>> Cc: Naveen Krishna Chatradhi <ch.naveen@...sung.com>
>>> Cc: linux-iio@...r.kernel.org
>>> Signed-off-by: Chanwoo Choi <cw00.choi@...sung.com>
>>> Signed-off-by: Kyungmin Park <kyungmin.park@...sung.com>
>>> ---
>>>  drivers/iio/adc/exynos_adc.c | 13 +++++++++++++
>>>  1 file changed, 13 insertions(+)
>>>
>>> diff --git a/drivers/iio/adc/exynos_adc.c
>b/drivers/iio/adc/exynos_adc.c
>>> index d25b262..4cd1975 100644
>>> --- a/drivers/iio/adc/exynos_adc.c
>>> +++ b/drivers/iio/adc/exynos_adc.c
>>> @@ -88,6 +88,7 @@ struct exynos_adc {
>>>       void __iomem            *regs;
>>>       void __iomem            *enable_reg;
>>>       struct clk              *clk;
>>> +     struct clk              *sclk;
>>>       unsigned int            irq;
>>>       struct regulator        *vdd;
>>>
>>> @@ -308,6 +309,13 @@ static int exynos_adc_probe(struct
>platform_device *pdev)
>>>               goto err_irq;
>>>       }
>>>
>>> +     info->sclk = devm_clk_get(&pdev->dev, "sclk_tsadc");
>>> +     if (IS_ERR(info->sclk)) {
>>> +             dev_warn(&pdev->dev, "failed getting sclk clock, err =
>%ld\n",
>>> +                                                    
>PTR_ERR(info->sclk));
>>> +             info->sclk = NULL;
>>> +     }
>>> +
>>>       info->vdd = devm_regulator_get(&pdev->dev, "vdd");
>>>       if (IS_ERR(info->vdd)) {
>>>               dev_err(&pdev->dev, "failed getting regulator, err =
>%ld\n",
>>> @@ -341,6 +349,7 @@ static int exynos_adc_probe(struct
>platform_device *pdev)
>>>               goto err_iio_dev;
>>>
>>>       clk_prepare_enable(info->clk);
>>> +     clk_prepare_enable(info->sclk);
>>>
>>>       exynos_adc_hw_init(info);
>>>
>>> @@ -357,6 +366,7 @@ err_of_populate:
>>>                               exynos_adc_remove_devices);
>>>       regulator_disable(info->vdd);
>>>       clk_disable_unprepare(info->clk);
>>> +     clk_disable_unprepare(info->sclk);
>>
>> Please disable clocks in the reverse of order in which they were
>enabled.
>
>Is it necessary? I don't think that.
It is probably not a bug but it is more obviously correct in the reverse order so that is how it should be done!
>
>Best Regards,
>Chanwoo Choi

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