From: Rob Herring <robh@kernel.org>
To: Vignesh R <vigneshr@ti.com>
Cc: Tony Lindgren <tony@atomide.com>,
nsekhar@ti.com, devicetree@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-omap@vger.kernel.org,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH 2/2] ARM: dts: dra7x: Support QSPI MODE-0 operation at 64MHz
Date: Thu, 14 Apr 2016 12:12:15 -0500 [thread overview]
Message-ID: <20160414171215.GA9860@rob-hp-laptop> (raw)
In-Reply-To: <1460629101-24309-3-git-send-email-vigneshr@ti.com>
On Thu, Apr 14, 2016 at 03:48:21PM +0530, Vignesh R wrote:
> According to Data Manual(SPRS915P) of AM57x, TI QSPI controller on
> DRA74(rev 1.1+)/DRA72 EVM can support up to 64MHz in MODE-0, whereas
> MODE-3 is limited to 48MHz. Hence, switch to MODE-0 for better
> throughput.
>
> Signed-off-by: Vignesh R <vigneshr@ti.com>
> ---
> Documentation/devicetree/bindings/spi/ti_qspi.txt | 7 +++++++
> arch/arm/boot/dts/dra7-evm.dts | 6 ++----
> arch/arm/boot/dts/dra72-evm.dts | 6 ++----
> 3 files changed, 11 insertions(+), 8 deletions(-)
>
> diff --git a/Documentation/devicetree/bindings/spi/ti_qspi.txt b/Documentation/devicetree/bindings/spi/ti_qspi.txt
> index cc8304aa64ac..50b14f6b53a3 100644
> --- a/Documentation/devicetree/bindings/spi/ti_qspi.txt
> +++ b/Documentation/devicetree/bindings/spi/ti_qspi.txt
> @@ -19,6 +19,13 @@ Optional properties:
> - syscon-chipselects: Handle to system control region contains QSPI
> chipselect register and offset of that register.
>
> +NOTE: TI QSPI controller requires different pinmux and IODelay
> +paramaters for Mode-0 and Mode-3 operations, which needs to be set up by
> +the bootloader (U-Boot). Default configuration only supports Mode-0
> +operation. Hence, "spi-cpol" and "spi-cpha" DT properties cannot be
> +specified in the slave nodes of TI QSPI controller without appropriate
> +modification to bootloader.
But these properties are properties of what the slave device supports,
right? I don't see how you can change them based on the controller.
Rob
next prev parent reply other threads:[~2016-04-14 17:12 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-04-14 10:18 [PATCH 0/2] DRA7x: Increase QSPI frequency to 64MHz Vignesh R
2016-04-14 10:18 ` [PATCH 1/2] ARM: dts: dra7x: Remove QSPI pinmux Vignesh R
2016-04-14 10:18 ` [PATCH 2/2] ARM: dts: dra7x: Support QSPI MODE-0 operation at 64MHz Vignesh R
2016-04-14 17:12 ` Rob Herring [this message]
2016-04-15 15:08 ` R, Vignesh
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