From: Maxime Ripard <maxime.ripard@free-electrons.com>
To: Icenowy Zheng <icenowy@aosc.xyz>
Cc: Hans de Goede <hdegoede@redhat.com>,
linux-kernel <linux-kernel@vger.kernel.org>,
linux-arm-kernel@lists.infradead.org, devicetree@vger.kernel.org,
Chen-Yu Tsai <wens@csie.org>
Subject: Re: [PATCH] ARM: dts: sun8i-q8-common: enable bluetooth on SDIO Wi-Fi
Date: Fri, 16 Dec 2016 13:47:48 +0100 [thread overview]
Message-ID: <20161216124748.rkvnnlo4x5onzpvk@lukather> (raw)
In-Reply-To: <20161213233658.atGuNCNY@smtp1h.mail.yandex.net>
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On Fri, Dec 09, 2016 at 07:49:00PM +0800, Icenowy Zheng wrote:
>
> 2016年12月9日 下午4:07于 Maxime Ripard <maxime.ripard@free-electrons.com>写道:
> >
> > On Tue, Dec 06, 2016 at 04:08:38PM +0800, Icenowy Zheng wrote:
> > > Some SDIO Wi-Fi chips (such as RTL8703AS) have a UART bluetooth, which
> > > has a dedicated enable pin (PL8 in the reference design).
> > >
> > > Enable the pin in the same way as the WLAN enable pins.
> > >
> > > Tested on an A33 Q8 tablet with RTL8703AS.
> > >
> > > Signed-off-by: Icenowy Zheng <icenowy@aosc.xyz>
> > > ---
> > >
> > > This patch should be coupled with the uart1 node patch I send before:
> > > http://lists.infradead.org/pipermail/linux-arm-kernel/2016-December/471997.html
> > >
> > > For RTL8703AS, the rtl8723bs bluetooth code is used, which can be retrieve from:
> > > https://github.com/lwfinger/rtl8723bs_bt
> > >
> > > arch/arm/boot/dts/sun8i-q8-common.dtsi | 2 +-
> > > 1 file changed, 1 insertion(+), 1 deletion(-)
> > >
> > > diff --git a/arch/arm/boot/dts/sun8i-q8-common.dtsi b/arch/arm/boot/dts/sun8i-q8-common.dtsi
> > > index c676940..4aeb5bb 100644
> > > --- a/arch/arm/boot/dts/sun8i-q8-common.dtsi
> > > +++ b/arch/arm/boot/dts/sun8i-q8-common.dtsi
> > > @@ -88,7 +88,7 @@
> > >
> > > &r_pio {
> > > wifi_pwrseq_pin_q8: wifi_pwrseq_pin@0 {
> > > - pins = "PL6", "PL7", "PL11";
> > > + pins = "PL6", "PL7", "PL8", "PL11";
> > > function = "gpio_in";
> > > bias-pull-up;
> > > };
> >
> > There's several things wrong here. The first one is that you rely
> > solely on the pinctrl state to maintain a reset line. This is very
> > fragile (especially since the GPIO pinctrl state are likely to go away
> > at some point), but it also means that if your driver wants to recover
> > from that situation at some point, it won't work.
> >
> > The other one is that the bluetooth and wifi chips are two devices in
> > linux, and you assign that pin to the wrong device (wifi).
> >
> > rfkill-gpio is made just for that, so please use it.
>
> The GPIO is not for the radio, but for the full Bluetooth part.
I know.
> If it's set to 0, then the bluetooth part will reset, and the
> hciattach will fail.
Both rfkill-gpio and rfkill-regulator will shutdown when called
(either by poking the reset pin or shutting down the regulator), so
that definitely seems like an expected behavior to put the device in
reset.
> The BSP uses this as a rfkill, and the result is that the bluetooth
> on/off switch do not work properly.
Then rfkill needs fixing, but working around it by hoping that the
core will probe an entirely different device, and enforcing a default
that the rest of the kernel might or might not change is both fragile
and wrong.
Maxime
--
Maxime Ripard, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com
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next parent reply other threads:[~2016-12-16 12:47 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20161213233658.atGuNCNY@smtp1h.mail.yandex.net>
2016-12-16 12:47 ` Maxime Ripard [this message]
[not found] ` <4720181481899200@web7g.yandex.ru>
2016-12-19 10:09 ` [PATCH] ARM: dts: sun8i-q8-common: enable bluetooth on SDIO Wi-Fi Maxime Ripard
[not found] ` <11985541482156512@web2g.yandex.ru>
2016-12-19 14:24 ` Chen-Yu Tsai
2016-12-20 13:50 ` Maxime Ripard
[not found] <20161206080838.7523-1-icenowy@aosc.xyz>
2016-12-09 8:07 ` Maxime Ripard
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