From: "Rafał Miłecki" <zajec5@gmail.com>
To: Florian Fainelli <f.fainelli@gmail.com>,
linux-arm-kernel@lists.infradead.org
Cc: Christian Lamparter <chunkeey@gmail.com>,
Hauke Mehrtens <hauke@hauke-m.de>,
"maintainer:BROADCOM BCM5301X ARM ARCHITECTURE"
<bcm-kernel-feedback-list@broadcom.com>,
Rob Herring <robh+dt@kernel.org>,
"open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS"
<devicetree@vger.kernel.org>,
open list <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] ARM: dts: BCM5301X: Fix pin controller node
Date: Thu, 20 Aug 2020 14:20:21 +0200 [thread overview]
Message-ID: <d4a3b850-7b19-bad7-383b-dfbc0f7c896c@gmail.com> (raw)
In-Reply-To: <20200819042308.19043-1-f.fainelli@gmail.com>
On 19.08.2020 06:23, Florian Fainelli wrote:
> The pin controller resources start at 0xc0 from the CRU base which is at
> 0x100 from th DMU base, for a final address of 0x1800_c1c0, whereas we
> are currently off by 0x100. The resource size of the CRU is also
> incorrect and should end at 0x248 bytes from 0x100 which is the start
> address. Finally, the compatibility strings defined for the
> pin-controller node should reflect the SoC being used.
I can confirm 0x1800c1c0 is the correct absolute offset.
> diff --git a/arch/arm/boot/dts/bcm5301x.dtsi b/arch/arm/boot/dts/bcm5301x.dtsi
> index 2d9b4dd05830..bf49943f504a 100644
> --- a/arch/arm/boot/dts/bcm5301x.dtsi
> +++ b/arch/arm/boot/dts/bcm5301x.dtsi
> @@ -402,14 +402,14 @@ dmu@1800c000 {
>
> cru@100 {
> compatible = "simple-bus";
> - reg = <0x100 0x1a4>;
> + reg = <0x100 0x248>;
> ranges;
> #address-cells = <1>;
> #size-cells = <1>;
>
> - pin-controller@1c0 {
> - compatible = "brcm,bcm4708-pinmux";
> - reg = <0x1c0 0x24>;
> + pinctrl: pin-controller@c0 {
> + compatible = "brcm,bcm53012-pinmux";
> + reg = <0xc0 0x24>;
> reg-names = "cru_gpio_control";
>
> spi-pins {
>
That whole binding has a bit messy story.
Initially it used to be binding like:
compatible = "brcm,bcm4708-pinmux";
reg = <0x1800c1c0 0x24>;
reg-names = "cru_gpio_control";
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=c12fb1774deaa9c9408b19db8d43d3612f6e47a0
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=3f9f82b3ffb8bfe01988c890e3a24328e9e1c1df
Later example binding was rewritten to include dmu and cru (simplified
below):
dmu@1800c000 {
compatible = "simple-bus";
ranges = <0 0x1800c000 0x1000>;
cru@100 {
compatible = "simple-bus";
reg = <0x100 0x1a4>;
ranges;
pin-controller@1c0 {
compatible = "brcm,bcm4708-pinmux";
reg = <0x1c0 0x24>;
reg-names = "cru_gpio_control";
};
};
};
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=93d39737b29eaf1974bf850ccdc903b2418c800b
I don't understand or remember why pin-controller reg was relative to
dmu instead of cru. Some DT offset calculation magic?
Finally I updated binding to use "offset", see:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=2ae80900f239484069569380e1fc4340fd6e0089
and then updated driver to follow:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=a49d784d5a8272d0f63c448fe8dc69e589db006e
but I never updated DTS file accordingly.
To OpenWrt I pushed relevant kernel patch in the commit:
https://git.openwrt.org/?p=openwrt/openwrt.git;a=commitdiff;h=a28f6ab27f9ae1a08c6945013cdb796b12ce150d
(called [PATCH] ARM: dts: BCM5301X: Update Northstar pinctrl binding)
but I never sent it upstream.
Florian: your change doesn't match docs or existing Linux driver:
1. Driver seems to ignore "reg"
2. Driver requires "offset"
3. Property "cru_gpio_control" is leftover (undocumented and unused)
I think we need to take a step back and cleanup Northstar bindings. Few
months ago I sent e-mail:
Subject: Proper DT bindings for Broadcom's DMU node
Message-ID: <7da2db8f-66d0-24ec-d3eb-84247b383a06@gmail.com>
I didn't get any reply from Rob who previously pointed out that
compatible = "syscon", "simple-mfd";
is not a valid compatibility.
I suggest we hold on on DTS update for a moment and switch back to my
question from March on designing proper bindings.
prev parent reply other threads:[~2020-08-20 12:20 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-19 4:23 Florian Fainelli
2020-08-19 15:27 ` Ray Jui
2020-08-19 15:36 ` Rafał Miłecki
2020-08-19 18:28 ` Florian Fainelli
2020-08-19 20:48 ` Christian Lamparter
2020-08-19 20:49 ` Florian Fainelli
2020-08-19 21:14 ` Ray Jui
2020-08-19 21:29 ` Florian Fainelli
2020-08-20 12:20 ` Rafał Miłecki [this message]
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