From: Vidya Sagar <vidyas@nvidia.com>
To: Thierry Reding <thierry.reding@gmail.com>
Cc: devicetree@vger.kernel.org, lorenzo.pieralisi@arm.com,
mmaddireddy@nvidia.com, kthota@nvidia.com,
gustavo.pimentel@synopsys.com, linux-kernel@vger.kernel.org,
kishon@ti.com, linux-tegra@vger.kernel.org, robh+dt@kernel.org,
linux-pci@vger.kernel.org, bhelgaas@google.com,
andrew.murray@arm.com, jonathanh@nvidia.com,
linux-arm-kernel@lists.infradead.org, sagar.tv@gmail.com
Subject: Re: [PATCH 6/6] arm64: tegra: Add support for PCIe endpoint mode in P2972-0000 platform
Date: Mon, 25 Nov 2019 13:03:27 +0530 [thread overview]
Message-ID: <4f92c07a-ea0f-a632-f5c5-b87666f8ecdd@nvidia.com> (raw)
In-Reply-To: <20191125072542.GC1409040@ulmo>
On 11/25/2019 12:55 PM, Thierry Reding wrote:
> On Mon, Nov 25, 2019 at 12:30:53PM +0530, Vidya Sagar wrote:
>> On 11/22/2019 6:55 PM, Thierry Reding wrote:
>>> On Fri, Nov 22, 2019 at 04:15:05PM +0530, Vidya Sagar wrote:
>>>> Add endpoint mode support for PCIe C5 controller in P2972-0000 platform
>>>> with information about supplies, PHY, PERST GPIO and GPIO that controls
>>>> PCIe reference clock coming from the host system.
>>>>
>>>> Signed-off-by: Vidya Sagar <vidyas@nvidia.com>
>>>> ---
>>>> .../boot/dts/nvidia/tegra194-p2972-0000.dts | 29 +++++++++++++++++++
>>>> 1 file changed, 29 insertions(+)
>>>>
>>>> diff --git a/arch/arm64/boot/dts/nvidia/tegra194-p2972-0000.dts b/arch/arm64/boot/dts/nvidia/tegra194-p2972-0000.dts
>>>> index 7eb64b816e08..58c3a9677bc8 100644
>>>> --- a/arch/arm64/boot/dts/nvidia/tegra194-p2972-0000.dts
>>>> +++ b/arch/arm64/boot/dts/nvidia/tegra194-p2972-0000.dts
>>>> @@ -43,6 +43,19 @@
>>>> gpio@c2f0000 {
>>>> status = "okay";
>>>> + /*
>>>> + * Change the below node's status to 'okay' when
>>>> + * PCIe C5 controller is enabled to operate in endpoint
>>>> + * to allow REFCLK from the host system to flow into
>>>> + * the controller.
>>>> + */
>>>> + pex-refclk-sel-high {
>>>> + gpio-hog;
>>>> + output-high;
>>>> + gpios = <TEGRA194_AON_GPIO(AA, 5) 0>;
>>>> + label = "pex_refclk_sel_high";
>>>> + status = "disabled";
>>>> + };
>>>
>>> Why don't we put this into the PCIe controller's node as a reference to
>>> that GPIO? Seems like the controller would know exactly when this pin
>>> needs to go high or low, so why does it have to be a hog?
>>>
>>> Thierry
>> Are you saying something like 'nvidia,enable-refclk-in'?
>> I was thinking, since this is like a board level configuration specific to Jetson-Xavier,
>> it would suffice to just hog it according to the mode of operation of PCIe controller.
>> But, I see one advantage of referencing it in the PCIe node (so that the driver can configure
>> it as and when needed) is that one has to be careful just to enable either PCIe RP or EP
>> node and not worry about other thing (like this).
>> Let me know if I got this right.
>
> Yeah, that's exactly why I think referencing this from the controller
> and controlling it in the driver is preferable.
>
> If this is some sort of select signal I think it makes sense to name it
> "nvidia,refclk-select-gpios" or something. Does this appear in the
> schematic somewhere? Or does the IP have a name for this? Those are
> usually good places to look for inspiration on the name because it's
> what hardware designers will be familiar with and they are technically
> the ones who should write the DT, even if that's rarely the case.
Schematic has "PEX_REFCLK_SEL" name.
I would go with 'nvidia,refclk-select-gpios' and make the change.
- Vidya Sagar
>
> Thierry
>
>>
>> - Vidya Sagar
>>
>>>
>>>> };
>>>> pwm@c340000 {
>>>> @@ -144,6 +157,22 @@
>>>> "p2u-5", "p2u-6", "p2u-7";
>>>> };
>>>> + pcie_ep@141a0000 {
>>>> + status = "disabled";
>>>> +
>>>> + vddio-pex-ctl-supply = <&vdd_1v8ao>;
>>>> +
>>>> + nvidia,pex-rst-gpio = <&gpio TEGRA194_MAIN_GPIO(GG, 1)
>>>> + GPIO_ACTIVE_LOW>;
>>>> +
>>>> + phys = <&p2u_nvhs_0>, <&p2u_nvhs_1>, <&p2u_nvhs_2>,
>>>> + <&p2u_nvhs_3>, <&p2u_nvhs_4>, <&p2u_nvhs_5>,
>>>> + <&p2u_nvhs_6>, <&p2u_nvhs_7>;
>>>> +
>>>> + phy-names = "p2u-0", "p2u-1", "p2u-2", "p2u-3", "p2u-4",
>>>> + "p2u-5", "p2u-6", "p2u-7";
>>>> + };
>>>> +
>>>> fan: fan {
>>>> compatible = "pwm-fan";
>>>> pwms = <&pwm4 0 45334>;
>>>> --
>>>> 2.17.1
>>>>
>>
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2019-11-25 7:33 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-22 10:44 [PATCH 0/6] Add support for PCIe endpoint mode in Tegra194 Vidya Sagar
2019-11-22 10:45 ` [PATCH 1/6] soc/tegra: bpmp: Update ABI header Vidya Sagar
2019-11-22 10:45 ` [PATCH 2/6] dt-bindings: PCI: tegra: Add DT support for PCIe EP nodes in Tegra194 Vidya Sagar
2019-11-22 13:19 ` Thierry Reding
2019-11-25 7:23 ` Vidya Sagar
2019-11-25 7:33 ` Thierry Reding
2019-11-25 11:52 ` Gustavo Pimentel
2019-11-29 13:26 ` Vidya Sagar
2019-12-05 9:57 ` Vidya Sagar
2019-12-04 21:43 ` Rob Herring
2019-11-22 10:45 ` [PATCH 3/6] PCI: tegra: Add support for PCIe endpoint mode " Vidya Sagar
2019-11-26 21:37 ` Bjorn Helgaas
2019-11-29 13:22 ` Vidya Sagar
2019-11-22 10:45 ` [PATCH 4/6] arm64: tegra: Add PCIe endpoint controllers nodes for Tegra194 Vidya Sagar
2019-11-22 10:45 ` [PATCH 5/6] arm64: tegra: Enable GPIO controllers nodes for P2972-0000 platform Vidya Sagar
2019-11-22 13:20 ` Thierry Reding
2019-11-25 6:55 ` Vidya Sagar
2019-11-22 10:45 ` [PATCH 6/6] arm64: tegra: Add support for PCIe endpoint mode in " Vidya Sagar
2019-11-22 13:25 ` Thierry Reding
2019-11-25 7:00 ` Vidya Sagar
2019-11-25 7:25 ` Thierry Reding
2019-11-25 7:33 ` Vidya Sagar [this message]
2019-11-25 7:37 ` Thierry Reding
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=4f92c07a-ea0f-a632-f5c5-b87666f8ecdd@nvidia.com \
--to=vidyas@nvidia.com \
--cc=andrew.murray@arm.com \
--cc=bhelgaas@google.com \
--cc=devicetree@vger.kernel.org \
--cc=gustavo.pimentel@synopsys.com \
--cc=jonathanh@nvidia.com \
--cc=kishon@ti.com \
--cc=kthota@nvidia.com \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-pci@vger.kernel.org \
--cc=linux-tegra@vger.kernel.org \
--cc=lorenzo.pieralisi@arm.com \
--cc=mmaddireddy@nvidia.com \
--cc=robh+dt@kernel.org \
--cc=sagar.tv@gmail.com \
--cc=thierry.reding@gmail.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).