From: Rob Herring <robh@kernel.org>
To: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: devicetree@vger.kernel.org, Mark Brown <broonie@kernel.org>,
Pratyush Yadav <p.yadav@ti.com>,
linux-spi@vger.kernel.org, Rob Herring <robh+dt@kernel.org>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 1/2] spi: Add optional number of additional clock cycles to be generated
Date: Mon, 7 Mar 2022 18:52:08 -0600 [thread overview]
Message-ID: <YiaouHFtlIG8nQxu@robh.at.kernel.org> (raw)
In-Reply-To: <6b6bad3844828c22de3acfb9e7fbac877a48d5a4.1646060734.git.christophe.leroy@csgroup.eu>
On Mon, 28 Feb 2022 16:15:45 +0100, Christophe Leroy wrote:
> Some components require a few clock cycles with chipselect off before
> or/and after the data transfer done with CS on.
>
> Typically IDT 801034 QUAD PCM CODEC datasheet states "Note *: CCLK
> should have one cycle before CS goes low, and two cycles after
> CS goes high".
>
> The cycles "before" are implicitely provided by all previous activity
> on the SPI bus. But the cycles "after" must be provided in order to
> achieve the SPI transfer.
>
> In order to use that kind of component, implement a new option for
> SPI slaves in order to implement trailing clock of a given number of
> bits with ChipSelect off at the end of the transfer.
>
> Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
> ---
> .../devicetree/bindings/spi/spi-peripheral-props.yaml | 5 +++++
> drivers/spi/spi.c | 7 +++++--
> include/linux/spi/spi.h | 1 +
> 3 files changed, 11 insertions(+), 2 deletions(-)
>
Acked-by: Rob Herring <robh@kernel.org>
next prev parent reply other threads:[~2022-03-08 0:52 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-28 15:15 [PATCH v2 0/2] Add support for components requiring trailing clock after transfer Christophe Leroy
2022-02-28 15:15 ` [PATCH v2 1/2] spi: Add optional number of additional clock cycles to be generated Christophe Leroy
2022-03-08 0:52 ` Rob Herring [this message]
2022-02-28 15:15 ` [PATCH v2 2/2] spi: fsl-spi: Implement trailing bits Christophe Leroy
2022-02-28 15:29 ` Mark Brown
2022-02-28 16:02 ` Christophe Leroy
2022-02-28 16:14 ` Mark Brown
2022-03-01 12:53 ` Christophe Leroy
2022-03-01 13:25 ` Mark Brown
2022-08-18 18:35 ` Christophe Leroy
2022-08-22 17:15 ` Mark Brown
2022-08-22 18:38 ` Christophe Leroy
2022-08-22 19:29 ` Mark Brown
2022-02-28 18:28 ` kernel test robot
2022-02-28 18:38 ` kernel test robot
2022-02-28 18:48 ` kernel test robot
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