From: Vinod Koul <vkoul@kernel.org>
To: Pratyush Yadav <p.yadav@ti.com>
Cc: Paul Kocialkowski <paul.kocialkowski@bootlin.com>,
Vignesh Raghavendra <vigneshr@ti.com>,
Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>,
Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
Nikhil Devshatwar <nikhil.nd@ti.com>,
Chunfeng Yun <chunfeng.yun@mediatek.com>,
Kishon Vijay Abraham I <kishon@ti.com>,
Rob Herring <robh+dt@kernel.org>,
linux-kernel@vger.kernel.org, linux-phy@lists.infradead.org
Subject: Re: [PATCH v5 2/6] phy: cdns-dphy: Add Rx support
Date: Fri, 1 Oct 2021 11:53:16 +0530 [thread overview]
Message-ID: <YVapVLnGfSBZCDTY@matsya> (raw)
In-Reply-To: <20210917172809.rjtf7ww7vjcfvey5@ti.com>
Hi Pratyush,
On 17-09-21, 22:58, Pratyush Yadav wrote:
> +Rob
>
> On 16/09/21 12:22PM, Paul Kocialkowski wrote:
> > Hi,
> >
> > On Fri 03 Sep 21, 00:25, Pratyush Yadav wrote:
> > > The Cadence DPHY can be used to receive image data over the CSI-2
> > > protocol. Add support for Rx mode. The programming sequence differs from
> > > the Tx mode so it is added as a separate set of hooks to isolate the two
> > > paths. The mode in which the DPHY has to be used is selected based on
> > > the compatible.
> >
> > I just realized that I didn't follow-up on a previous revision on the debate
> > about using the phy sub-mode to distinguish between rx/tx.
> >
> > I see that you've been using a dedicated compatible, but I'm not sure this is a
> > good fit either. My understanding is that the compatible should describe a group
> > of register-compatible revisions of a hardware component, not how the hardware
> > is used specifically. I guess the distinction between rx/tx falls under
> > the latter rather than the former.
>
> I am not sure if that is the case. For example, we use "ti,am654-ospi"
> for Cadence Quadspi controller. The default compatible, "cdns,qspi-nor",
> only supports Quad SPI (4 lines). The "ti,am654-ospi" compatible also
> supports Octal SPI (8 lines).
Those are hardware defaults right?
> In addition, I feel like the Rx DPHY is almost a different type of
> device from a Tx DPHY. The programming sequence is completely different,
Is that due to direction or something else..?
> the clocks required are different, etc. So I think using a different
> compatible for Rx mode makes sense.
Is the underlaying IP not capable of both TX and RX and in the specific
situations you are using it as TX and RX.
I am okay that default being TX but you can use Paul's approach of
direction with this to make it better proposal
--
~Vinod
--
linux-phy mailing list
linux-phy@lists.infradead.org
https://lists.infradead.org/mailman/listinfo/linux-phy
WARNING: multiple messages have this Message-ID (diff)
From: Vinod Koul <vkoul@kernel.org>
To: Pratyush Yadav <p.yadav@ti.com>
Cc: Paul Kocialkowski <paul.kocialkowski@bootlin.com>,
Vignesh Raghavendra <vigneshr@ti.com>,
Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>,
Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
Nikhil Devshatwar <nikhil.nd@ti.com>,
Chunfeng Yun <chunfeng.yun@mediatek.com>,
Kishon Vijay Abraham I <kishon@ti.com>,
Rob Herring <robh+dt@kernel.org>,
linux-kernel@vger.kernel.org, linux-phy@lists.infradead.org
Subject: Re: [PATCH v5 2/6] phy: cdns-dphy: Add Rx support
Date: Fri, 1 Oct 2021 11:53:16 +0530 [thread overview]
Message-ID: <YVapVLnGfSBZCDTY@matsya> (raw)
In-Reply-To: <20210917172809.rjtf7ww7vjcfvey5@ti.com>
Hi Pratyush,
On 17-09-21, 22:58, Pratyush Yadav wrote:
> +Rob
>
> On 16/09/21 12:22PM, Paul Kocialkowski wrote:
> > Hi,
> >
> > On Fri 03 Sep 21, 00:25, Pratyush Yadav wrote:
> > > The Cadence DPHY can be used to receive image data over the CSI-2
> > > protocol. Add support for Rx mode. The programming sequence differs from
> > > the Tx mode so it is added as a separate set of hooks to isolate the two
> > > paths. The mode in which the DPHY has to be used is selected based on
> > > the compatible.
> >
> > I just realized that I didn't follow-up on a previous revision on the debate
> > about using the phy sub-mode to distinguish between rx/tx.
> >
> > I see that you've been using a dedicated compatible, but I'm not sure this is a
> > good fit either. My understanding is that the compatible should describe a group
> > of register-compatible revisions of a hardware component, not how the hardware
> > is used specifically. I guess the distinction between rx/tx falls under
> > the latter rather than the former.
>
> I am not sure if that is the case. For example, we use "ti,am654-ospi"
> for Cadence Quadspi controller. The default compatible, "cdns,qspi-nor",
> only supports Quad SPI (4 lines). The "ti,am654-ospi" compatible also
> supports Octal SPI (8 lines).
Those are hardware defaults right?
> In addition, I feel like the Rx DPHY is almost a different type of
> device from a Tx DPHY. The programming sequence is completely different,
Is that due to direction or something else..?
> the clocks required are different, etc. So I think using a different
> compatible for Rx mode makes sense.
Is the underlaying IP not capable of both TX and RX and in the specific
situations you are using it as TX and RX.
I am okay that default being TX but you can use Paul's approach of
direction with this to make it better proposal
--
~Vinod
next prev parent reply other threads:[~2021-10-01 6:23 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-02 18:55 [PATCH v5 0/6] Rx mode support for Cadence DPHY Pratyush Yadav
2021-09-02 18:55 ` Pratyush Yadav
2021-09-02 18:55 ` [PATCH v5 1/6] phy: cdns-dphy: Prepare for Rx support Pratyush Yadav
2021-09-02 18:55 ` Pratyush Yadav
2021-10-07 0:02 ` Laurent Pinchart
2021-10-07 0:02 ` Laurent Pinchart
2021-09-02 18:55 ` [PATCH v5 2/6] phy: cdns-dphy: Add " Pratyush Yadav
2021-09-02 18:55 ` Pratyush Yadav
2021-09-16 10:22 ` Paul Kocialkowski
2021-09-16 10:22 ` Paul Kocialkowski
2021-09-17 17:28 ` Pratyush Yadav
2021-09-17 17:28 ` Pratyush Yadav
2021-09-28 16:35 ` Pratyush Yadav
2021-09-28 16:35 ` Pratyush Yadav
2021-10-01 6:23 ` Vinod Koul [this message]
2021-10-01 6:23 ` Vinod Koul
2021-10-01 8:07 ` Pratyush Yadav
2021-10-01 8:07 ` Pratyush Yadav
2021-10-07 0:10 ` Laurent Pinchart
2021-10-07 0:10 ` Laurent Pinchart
2021-10-07 12:14 ` Pratyush Yadav
2021-10-07 12:14 ` Pratyush Yadav
2021-10-08 10:27 ` Laurent Pinchart
2021-10-08 10:27 ` Laurent Pinchart
2021-10-08 12:55 ` Paul Kocialkowski
2021-10-08 12:55 ` Paul Kocialkowski
2021-10-25 8:09 ` Vinod Koul
2021-10-25 8:09 ` Vinod Koul
2021-09-02 18:55 ` [PATCH v5 3/6] phy: dt-bindings: Convert Cadence DPHY binding to YAML Pratyush Yadav
2021-09-02 18:55 ` Pratyush Yadav
2021-09-02 18:55 ` [PATCH v5 4/6] phy: dt-bindings: cdns, dphy: make clocks optional for Rx mode Pratyush Yadav
2021-09-02 18:55 ` [PATCH v5 4/6] phy: dt-bindings: cdns,dphy: " Pratyush Yadav
2021-09-07 19:02 ` [PATCH v5 4/6] phy: dt-bindings: cdns, dphy: " Rob Herring
2021-09-07 19:02 ` [PATCH v5 4/6] phy: dt-bindings: cdns,dphy: " Rob Herring
2021-10-06 23:57 ` [PATCH v5 4/6] phy: dt-bindings: cdns, dphy: " Laurent Pinchart
2021-10-06 23:57 ` [PATCH v5 4/6] phy: dt-bindings: cdns,dphy: " Laurent Pinchart
2021-09-02 18:55 ` [PATCH v5 5/6] phy: dt-bindings: cdns, dphy: add power-domains property Pratyush Yadav
2021-09-02 18:55 ` [PATCH v5 5/6] phy: dt-bindings: cdns,dphy: " Pratyush Yadav
2021-09-02 18:55 ` [PATCH v5 6/6] phy: dt-bindings: cdns,dphy: add Rx DPHY compatible Pratyush Yadav
2021-09-02 18:55 ` Pratyush Yadav
2021-09-07 19:03 ` Rob Herring
2021-09-07 19:03 ` Rob Herring
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