Re: [PATCH] spi: s3c64xx: do not disable the clock while configuring the spi

From: Krzysztof Kozlowski <k.kozlowski@samsung.com>
To: Andi Shyti <andi.shyti@samsung.com>, Mark Brown <broonie@kernel.org>
Cc: Sylwester Nawrocki <s.nawrocki@samsung.com>,
	Kukjin Kim <kgene@kernel.org>,
	linux-arm-kernel@lists.infradead.org,
	linux-samsung-soc@vger.kernel.org, linux-spi@vger.kernel.org,
	linux-kernel@vger.kernel.org, Andi Shyti <andi@etezian.org>
Subject: Re: [PATCH] spi: s3c64xx: do not disable the clock while configuring the spi
Date: Thu, 07 Jul 2016 11:41:49 +0200	[thread overview]
Message-ID: <577E23DD.1040906@samsung.com> (raw)
In-Reply-To: <1467876237-12183-1-git-send-email-andi.shyti@samsung.com>

On 07/07/2016 09:23 AM, Andi Shyti wrote:
> When the clock is coming from the cmu it is not required to be
> disabled and then re-enabled in order to change the rate.
> 
> Besides, some exynos chipsets (e.g. exynos5433) do not deliver
> any to the SFR if one from the pclk ("spi" in this case) or sclk
> ("busclk") is disabled.
> 
> Remove the clock disabling/enabling to avoid falling into this
> situation.
> 
> Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
> Signed-off-by: Andi Shyti <andi.shyti@samsung.com>
> ---
> 
> Hi,
> 
> This patch has been tested by me and Sylwester on Trats2
> (exynos4412) and tm2(e) (exynos5433) boards, for big data
> (which use dma transfer) and small data.
> 
> It also fixes in exynos5433 a synchronus abort caused by the fact
> that the pclk (spi) doesn't get delivered if the sclk is disabled
> (busclk)
> 
> Thanks,
> Andi
> 
>  drivers/spi/spi-s3c64xx.c | 8 +-------
>  1 file changed, 1 insertion(+), 7 deletions(-)

Reviewed-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>

Best regards,
Krzysztof