From: arend@broadcom•com (Arend van Spriel)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH] ARM: tegra: add device tree for SHIELD
Date: Tue, 25 Feb 2014 10:52:52 +0100 [thread overview]
Message-ID: <530C67F4.7010208@broadcom.com> (raw)
In-Reply-To: <530BFC58.6020003@nvidia.com>
On 02/25/2014 03:13 AM, Alexandre Courbot wrote:
>>
>>> + /* Wifi */
>>> + sdhci at 78000000 {
>>> + status = "okay";
>>> + bus-width = <4>;
>>> + broken-cd;
>>> + keep-power-in-suspend;
>>> + cap-sdio-irq;
>>
>> Is non-removable better than broken-cd, or are they entirely unrelated?
>
> They are unrelated actually. With non-removable the driver expects the
> device to always be there since boot, and does not check for the card to
> be removed/added after boot. broken-cd indicates there is no CD line and
> the device should be polled regularly.
>
> For the Wifi chip, non-removable would be the correct setting
> hardware-wise, but there is a trap: the chip has its reset line asserted
> at boot-time, and you need to set GPIO 229 to de-assert it. Only after
> that will the device be detected on the SDIO bus. Since it lacks a CD
> line, it must be polled, hence the broken-cd property.
>
> This also raises another, redundant problem with DT bindings: AFAIK we
> currently have no way to let the system know the device will only appear
> after a given GPIO is set. It would also be nice to be able to give some
> parameters to the Wifi driver through the DT (like the OOB interrupt).
> Right now the Wifi chip is brought up by exporting the GPIO and writing
> to it from user-space, and the OOB interrupt is not used.
Hi Alexandre,
I recently posted a proposal for brcmfmac DT binding [1]. I did receive
some comments, but it would be great if you (and/or others involved) had
a look at it as well and give me some feedback. DT work still needs to
grow on me.
> Otherwise, Wifi works great with the brcmfmac driver and NVRAM file
> extracted from Android.
With in-band interrupts, indeed. The HOST_WAKE signal is the OOB
interrupt which would need to be provided in the device-tree.
Regards,
Arend
[1] http://mid.gmane.org/1392059868-8782-1-git-send-email-arend at broadcom.com
next prev parent reply other threads:[~2014-02-25 9:52 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-02-24 10:26 [PATCH] ARM: tegra: add device tree for SHIELD Alexandre Courbot
2014-02-24 18:53 ` Stephen Warren
2014-02-25 2:13 ` Alexandre Courbot
2014-02-25 9:52 ` Arend van Spriel [this message]
2014-02-26 4:52 ` Alexandre Courbot
2014-02-26 21:10 ` Arend van Spriel
2014-02-25 22:38 ` Stephen Warren
2014-02-26 4:58 ` Alexandre Courbot
2014-02-26 5:02 ` Stephen Warren
2014-02-26 5:12 ` Alexandre Courbot
-- strict thread matches above, loose matches on Subject: below --
2014-03-03 3:49 Alexandre Courbot
2014-03-03 3:53 ` Alexandre Courbot
2014-03-03 17:00 ` Stephen Warren
2014-03-04 1:24 ` Alexandre Courbot
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