From: Michael Walle <mwalle@kernel.org>
To: haibo.chen@nxp.com
Cc: broonie@kernel.org, han.xu@nxp.com, linux-imx@nxp.com,
linux-spi@vger.kernel.org, yogeshgaur.83@gmail.com,
Michael Walle <mwalle@kernel.org>
Subject: Re: [PATCH 4/5] spi: spi-nxp-fspi: add function to select sample clock source for flash reading
Date: Wed, 13 Dec 2023 18:21:13 +0100 [thread overview]
Message-ID: <20231213172113.2774476-1-mwalle@kernel.org> (raw)
In-Reply-To: <20231213091346.956789-4-haibo.chen@nxp.com>
> From: Haibo Chen <haibo.chen@nxp.com>
>
> fspi define four mode for sample clock source selection.
>
> Here is the list of modes:
> mode 0: Dummy Read strobe generated by FlexSPI Controller and loopback internally
> mode 1: Dummy Read strobe generated by FlexSPI Controller and loopback from DQS pad
> mode 2: Reserved
> mode 3: Flash provided Read strobe and input from DQS pad
>
> In default, fspi use mode 0 after reset.
> For 8-8-8-DTR mode, need to use mode 3, otherwise 8-8-8-DTR read always
> get incorrect data.
I'd say this is board dependant, right? If you now hardcode 8d8d8d
to always use mode 3. I'm not sure how a board which doesn't have
the DQS connected to the flash can change this to another mode
again. Looks like we'd need a (DT) property which tells you if
there is actually a DQS line connected to the flash.
Btw you don't check buswidth, so you'll enable that mode for any
DTR mode.
-michael
next prev parent reply other threads:[~2023-12-13 17:21 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-12-13 9:13 [PATCH 1/5] spi: spi-nxp-fspi: enable runtime pm for fspi haibo.chen
2023-12-13 9:13 ` [PATCH 2/5] spi: spi-nxp-fspi: change the default lut index haibo.chen
2023-12-13 16:24 ` Michael Walle
2023-12-14 2:10 ` Bough Chen
2023-12-14 3:04 ` Adam Ford
2023-12-14 4:00 ` Bough Chen
2023-12-13 9:13 ` [PATCH 3/5] spi: spi-nxp-fspi: add DTR mode support haibo.chen
2023-12-13 16:53 ` Michael Walle
2023-12-14 3:09 ` Bough Chen
2023-12-14 9:45 ` Michael Walle
2023-12-13 9:13 ` [PATCH 4/5] spi: spi-nxp-fspi: add function to select sample clock source for flash reading haibo.chen
2023-12-13 17:21 ` Michael Walle [this message]
2023-12-14 7:54 ` Bough Chen
2023-12-14 8:56 ` Michael Walle
2023-12-13 9:13 ` [PATCH 5/5] spi: spi-nxp-fspi: Add quirk to disable DTR support haibo.chen
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