From: Sylwester Nawrocki <s.nawrocki@samsung.com>
To: Michael Turquette <mturquette@baylibre.com>
Cc: Andi Shyti <andi.shyti@samsung.com>,
Rob Herring <robh+dt@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Kukjin Kim <kgene@kernel.org>,
Krzysztof Kozlowski <k.kozlowski@samsung.com>,
Mark Brown <broonie@kernel.org>,
Tomasz Figa <tomasz.figa@gmail.com>,
Stephen Boyd <sboyd@codeaurora.org>,
Chanwoo Choi <cw00.choi@samsung.com>,
Jaehoon Chung <jh80.chung@samsung.com>,
linux-clk@vger.kernel.org, devicetree@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
linux-samsung-soc@vger.kernel.org, linux-spi@vger.kernel.org,
Andi Shyti <andi@etezian.org>
Subject: Re: [PATCH v2 6/7] spi: s3c64xx: restore removed comments
Date: Tue, 12 Jul 2016 14:16:40 +0200 [thread overview]
Message-ID: <5784DFA8.60606@samsung.com> (raw)
In-Reply-To: <146827545163.73491.5083923656346798965@resonance>
On 07/12/2016 12:17 AM, Michael Turquette wrote:
> Quoting Sylwester Nawrocki (2016-07-11 03:33:42)
>> On 07/08/2016 06:17 PM, Michael Turquette wrote:
> Sure, but it's only a few lines of code to this, and there are examples
> in the kernel already.
>
>> Additionally, the "There is half-multiplier before the SPI" comment
>> seems to be obfuscating how the hardware really looks like to me.
>> It talks about multiplier (which reminds me of PLLs with a divider
>> in the feedback loop) while there is a simple divider which should
>> be considered as an integral part of the controller IP block.
>>
>> While we are at it, I'd propose to change this comment to something
>> like:
>>
>> /* The SCLK_SPI clock is divided internally by 2 */
>
> It's your choice, but debug output would benefit from showing the real
> clock frequency at some point.
OK, it's indeed fairly easy to add a fixed rate divide-by-two clock,
but for the older SoCs we would need to also model the internal mux, gate,
and an 8-bit divider. Then it becomes a bit bigger task. Anyway it might
be worth to try it, this could let us deprecate the samsung,spi-src-clk
property and for all the SoCs use assigned-clock-parents.
--
Thanks,
Sylwester
WARNING: multiple messages have this Message-ID (diff)
From: s.nawrocki@samsung.com (Sylwester Nawrocki)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v2 6/7] spi: s3c64xx: restore removed comments
Date: Tue, 12 Jul 2016 14:16:40 +0200 [thread overview]
Message-ID: <5784DFA8.60606@samsung.com> (raw)
In-Reply-To: <146827545163.73491.5083923656346798965@resonance>
On 07/12/2016 12:17 AM, Michael Turquette wrote:
> Quoting Sylwester Nawrocki (2016-07-11 03:33:42)
>> On 07/08/2016 06:17 PM, Michael Turquette wrote:
> Sure, but it's only a few lines of code to this, and there are examples
> in the kernel already.
>
>> Additionally, the "There is half-multiplier before the SPI" comment
>> seems to be obfuscating how the hardware really looks like to me.
>> It talks about multiplier (which reminds me of PLLs with a divider
>> in the feedback loop) while there is a simple divider which should
>> be considered as an integral part of the controller IP block.
>>
>> While we are at it, I'd propose to change this comment to something
>> like:
>>
>> /* The SCLK_SPI clock is divided internally by 2 */
>
> It's your choice, but debug output would benefit from showing the real
> clock frequency at some point.
OK, it's indeed fairly easy to add a fixed rate divide-by-two clock,
but for the older SoCs we would need to also model the internal mux, gate,
and an 8-bit divider. Then it becomes a bit bigger task. Anyway it might
be worth to try it, this could let us deprecate the samsung,spi-src-clk
property and for all the SoCs use assigned-clock-parents.
--
Thanks,
Sylwester
next prev parent reply other threads:[~2016-07-12 12:16 UTC|newest]
Thread overview: 95+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-07-08 14:46 [PATCH v2 0/7] spi s3c64xx ioclk handling Andi Shyti
2016-07-08 14:46 ` Andi Shyti
2016-07-08 14:46 ` Andi Shyti
2016-07-08 14:46 ` [PATCH v2 1/7] bindings: spi-samsung: add exynos5433 spi compatible Andi Shyti
2016-07-08 14:46 ` Andi Shyti
2016-07-08 20:23 ` Krzysztof Kozlowski
2016-07-08 20:23 ` Krzysztof Kozlowski
2016-07-11 10:49 ` Sylwester Nawrocki
2016-07-11 10:49 ` Sylwester Nawrocki
2016-07-11 10:49 ` Sylwester Nawrocki
2016-07-14 16:33 ` Applied "spi: s3c64xx: add exynos5433 spi compatible" to the spi tree Mark Brown
2016-07-14 16:33 ` Mark Brown
2016-07-14 16:33 ` Mark Brown
2016-07-08 14:46 ` [PATCH v2 2/7] bindings: spi-samsung: document the clocks and the clock-name property Andi Shyti
2016-07-08 14:46 ` Andi Shyti
2016-07-08 20:32 ` Krzysztof Kozlowski
2016-07-08 20:32 ` Krzysztof Kozlowski
2016-07-11 2:36 ` [PATCH v3] " Andi Shyti
2016-07-11 2:36 ` Andi Shyti
2016-07-11 2:36 ` Andi Shyti
2016-07-14 16:32 ` Applied "spi: s3c64xx: document the clocks and the clock-name property" to the spi tree Mark Brown
2016-07-14 16:32 ` Mark Brown
2016-07-14 16:32 ` Mark Brown
2016-07-08 14:46 ` [PATCH v2 3/7] spi: s3c64xx: rename goto labels to meaningful names Andi Shyti
2016-07-08 14:46 ` Andi Shyti
2016-07-14 16:32 ` Applied "spi: s3c64xx: rename goto labels to meaningful names" to the spi tree Mark Brown
2016-07-14 16:32 ` Mark Brown
2016-07-14 16:32 ` Mark Brown
2016-07-14 16:32 ` Mark Brown
2016-07-08 14:46 ` [PATCH v2 4/7] spi: s3c64xx: use error code from clk_prepare_enable() Andi Shyti
2016-07-08 14:46 ` Andi Shyti
2016-07-08 20:33 ` Krzysztof Kozlowski
2016-07-08 20:33 ` Krzysztof Kozlowski
2016-07-14 16:32 ` Applied "spi: s3c64xx: use error code from clk_prepare_enable()" to the spi tree Mark Brown
2016-07-14 16:32 ` Mark Brown
2016-07-14 16:32 ` Mark Brown
2016-07-08 14:46 ` [PATCH v2 5/7] spi: s3c64xx: add exynos5433 compatible for ioclk handling Andi Shyti
2016-07-08 14:46 ` Andi Shyti
2016-07-08 14:46 ` Andi Shyti
2016-07-08 16:13 ` Michael Turquette
2016-07-08 16:13 ` Michael Turquette
2016-07-08 16:13 ` Michael Turquette
2016-07-08 16:13 ` Michael Turquette
2016-07-08 16:31 ` Andi Shyti
2016-07-08 16:31 ` Andi Shyti
2016-07-08 20:39 ` Krzysztof Kozlowski
2016-07-08 20:39 ` Krzysztof Kozlowski
2016-07-14 16:32 ` Applied "spi: s3c64xx: add Exynos5433 compatible for ioclk handling" to the spi tree Mark Brown
2016-07-14 16:32 ` Mark Brown
2016-07-14 16:32 ` Mark Brown
2016-07-08 14:46 ` [PATCH v2 6/7] spi: s3c64xx: restore removed comments Andi Shyti
2016-07-08 14:46 ` Andi Shyti
2016-07-08 16:17 ` Michael Turquette
2016-07-08 16:17 ` Michael Turquette
2016-07-08 16:17 ` Michael Turquette
2016-07-08 16:17 ` Michael Turquette
2016-07-08 16:35 ` Andi Shyti
2016-07-08 16:35 ` Andi Shyti
2016-07-08 16:35 ` Andi Shyti
2016-07-11 10:33 ` Sylwester Nawrocki
2016-07-11 10:33 ` Sylwester Nawrocki
2016-07-11 22:17 ` Michael Turquette
2016-07-11 22:17 ` Michael Turquette
2016-07-11 22:17 ` Michael Turquette
2016-07-12 12:16 ` Sylwester Nawrocki [this message]
2016-07-12 12:16 ` Sylwester Nawrocki
2016-07-12 6:54 ` [PATCH v3 " Andi Shyti
2016-07-12 6:54 ` Andi Shyti
2016-07-12 8:22 ` Mark Brown
2016-07-12 8:22 ` Mark Brown
2016-07-12 8:22 ` Mark Brown
2016-07-12 8:25 ` Andi Shyti
2016-07-12 8:25 ` Andi Shyti
2016-07-12 8:25 ` Andi Shyti
2016-07-12 9:00 ` Mark Brown
2016-07-12 9:00 ` Mark Brown
2016-07-12 18:07 ` Michael Turquette
2016-07-12 18:07 ` Michael Turquette
2016-07-12 18:07 ` Michael Turquette
2016-07-12 18:07 ` Michael Turquette
2016-07-14 16:32 ` Applied "spi: s3c64xx: restore removed comments" to the spi tree Mark Brown
2016-07-14 16:32 ` Mark Brown
2016-07-14 16:32 ` Mark Brown
2016-07-14 16:32 ` Mark Brown
2016-07-08 20:35 ` [PATCH v2 6/7] spi: s3c64xx: restore removed comments Krzysztof Kozlowski
2016-07-08 20:35 ` Krzysztof Kozlowski
2016-07-08 20:35 ` Krzysztof Kozlowski
2016-07-08 14:46 ` [PATCH v2 7/7] clk: exynos5433: remove CLK_IGNORE_UNUSED flag from SPI clocks Andi Shyti
2016-07-08 14:46 ` Andi Shyti
2016-07-11 10:58 ` Sylwester Nawrocki
2016-07-11 10:58 ` Sylwester Nawrocki
2016-07-08 16:21 ` [PATCH v2 0/7] spi s3c64xx ioclk handling Michael Turquette
2016-07-08 16:21 ` Michael Turquette
2016-07-08 16:21 ` Michael Turquette
2016-07-08 16:21 ` Michael Turquette
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