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From: Michael Walle <michael@walle.cc>
To: Pratyush Yadav <p.yadav@ti.com>
Cc: Tudor.Ambarus@microchip.com, nm@ti.com, kristo@kernel.org,
	robh+dt@kernel.org, miquel.raynal@bootlin.com, richard@nod.at,
	vigneshr@ti.com, broonie@kernel.org,
	linux-arm-kernel@lists.infradead.org, devicetree@vger.kernel.org,
	linux-kernel@vger.kernel.org, linux-mtd@lists.infradead.org,
	linux-spi@vger.kernel.org, lokeshvutla@ti.com
Subject: Re: [RFC PATCH 0/6] spi: Add OSPI PHY calibration support for spi-cadence-quadspi
Date: Fri, 12 Mar 2021 11:20:15 +0100
Message-ID: <676386736df5e5b22e34b0b5af91c894@walle.cc> (raw)
In-Reply-To: <20210312101036.jfz2733ssv4nhfey@ti.com>

Am 2021-03-12 11:10, schrieb Pratyush Yadav:
> There is usually a delay from when the flash drives the data line (IOW,
> puts a data bit on it) and when the signal reaches the controller. This
> delay can vary by the flash, board, silicon characteristics,
> temperature, etc.

Temperature might change over time, but the calibration is only done
once. I don't know how much influence the temperature actually has, but
our boards are usually operating from -40°C to +85°C. So there might be
a possible temperature difference of 125K between actual calibration and
when the flash is accessed.

-michael

  reply index

Thread overview: 33+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-11 19:12 Pratyush Yadav
2021-03-11 19:12 ` [RFC PATCH 1/6] spi: spi-mem: Tell controller when device is ready for calibration Pratyush Yadav
2021-03-23 23:07   ` Michael Walle
2021-03-24  8:08     ` Pratyush Yadav
2021-04-29 16:23       ` Michael Walle
2021-04-29 18:41         ` Pratyush Yadav
2021-04-29 22:46           ` Michael Walle
2021-03-11 19:12 ` [RFC PATCH 2/6] mtd: spi-nor: core: consolidate read op creation Pratyush Yadav
2021-03-23 23:17   ` Michael Walle
2021-03-24  8:04     ` Pratyush Yadav
2021-04-08 12:48   ` Michael Walle
2021-03-11 19:12 ` [RFC PATCH 3/6] mtd: spi-nor: core: run calibration when initialization is done Pratyush Yadav
2021-03-11 19:12 ` [RFC PATCH 4/6] spi: cadence-qspi: Use PHY for DAC reads if possible Pratyush Yadav
2021-03-12  9:13   ` Tudor.Ambarus
2021-03-12 10:17     ` Pratyush Yadav
2021-04-29 16:28       ` Michael Walle
2021-04-29 18:19         ` Pratyush Yadav
2021-04-29 22:20           ` Michael Walle
2021-05-10 11:39             ` Pratyush Yadav
2021-03-11 19:12 ` [RFC PATCH 5/6] spi: cadence-qspi: Tune PHY to allow running at higher frequencies Pratyush Yadav
2021-04-29 22:48   ` Michael Walle
2021-04-30  5:42     ` Pratyush Yadav
2021-03-11 19:12 ` [RFC PATCH 6/6] arm64: dts: ti: k3-j721e-som-p0: Enable PHY calibration Pratyush Yadav
2021-03-12  9:09 ` [RFC PATCH 0/6] spi: Add OSPI PHY calibration support for spi-cadence-quadspi Tudor.Ambarus
2021-03-12 10:10   ` Pratyush Yadav
2021-03-12 10:20     ` Michael Walle [this message]
2021-03-12 11:07       ` Pratyush Yadav
2021-03-12 13:26         ` Michael Walle
2021-03-12 11:23     ` Tudor.Ambarus
2021-03-12 18:14       ` Pratyush Yadav
2021-03-12 13:32 ` Michael Walle
2021-03-12 14:59   ` Tudor.Ambarus
2021-03-12 17:00   ` Pratyush Yadav

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