Re: [PATCH] arm: dts: gta04: add gps support

On Mon, Jan 28, 2019 at 05:44:29PM +0100, Andreas Kemnade wrote:

On Mon, 28 Jan 2019 08:53:56 +0100
Johan Hovold [off-list ref] wrote:

quoted

On Fri, Jan 25, 2019 at 08:43:10PM +0100, Andreas Kemnade wrote:

quoted

The GTA04 has a w2sg0004 or w2sg0084 gps chip. Not detectable
which one is mounted so use the compatibility entry for w2sg0004
for all which will work for both.

Signed-off-by: Andreas Kemnade <andreas@kemnade.info>
---
w2sg0004 bindings (together with the corresponding support is in
https://git.kernel.org/pub/scm/linux/kernel/git/johan/gnss gnss-next)
 arch/arm/boot/dts/omap3-gta04.dtsi | 13 +++++++++++++
 1 file changed, 13 insertions(+)

quoted

quoted

+	gps: gps {  

The node should be named "gnss" as per the binding.

quoted

+		compatible = "wi2wi,w2sg0004";
+		pinctrl-names = "default";
+		pinctrl-0 = <&gps_pins>;
+		sirf,onoff-gpios = <&gpio5 17 GPIO_ACTIVE_HIGH>;
+		lna-supply = <&vsim>;  

Also, the vcc-supply is a required property.

well, it is not require in the driver and it has different behavior
(on even when not opened if on-off is there) than the lna-supply used
here. So maybe fix the binding documentation?

The device-tree describes hardware, and how a particular driver happens
to implement a binding is not relevant.

That said, there is a bit of an on-going, shall we say philosophical,
debate about this. The regulator maintainer takes a firm position that
all mandatory physical supplies should be represented in firmware
	
	https://lore.kernel.org/lkml/20181123133126.GF2089@sirena.org.uk/T/#u (local)
	https://lore.kernel.org/lkml/20180409102244.GB11532@sirena.org.uk/T/#u (local)

while Rob appears to take a slightly different stance on fixed
regulators while admitting that this an issue which has not yet been
fully resolved:

	https://lore.kernel.org/lkml/20180425171123.xhyoay3nu463btoq@rob-hp-laptop/T/#u (local)

Since this is a new binding, and the hardware requires the vcc supply
and this is reflected in the binding, I think you should add a fixed
regulator. At least until you hear otherwise. ;)

Johan