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Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1tcc6S-000000040D8-1kiA; Tue, 28 Jan 2025 03:17:28 +0000 Received: from mail.gentoo.org ([2001:470:ea4a:1:5054:ff:fec7:86e4] helo=smtp.gentoo.org) by bombadil.infradead.org with esmtps (Exim 4.98 #2 (Red Hat Linux)) id 1tcc6P-000000040Ce-1YCD for linux-riscv@lists.infradead.org; Tue, 28 Jan 2025 03:17:26 +0000 Received: from localhost (unknown [116.232.60.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (prime256v1) server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: dlan) by smtp.gentoo.org (Postfix) with ESMTPSA id B2AFA343787; Tue, 28 Jan 2025 03:17:16 +0000 (UTC) Date: Tue, 28 Jan 2025 03:17:12 +0000 From: Yixun Lan To: Rob Herring Subject: Re: [PATCH v4 1/4] dt-bindings: gpio: spacemit: add support for K1 SoC Message-ID: <20250128031712-GYB47737@gentoo> References: <20250121-03-k1-gpio-v4-0-4641c95c0194@gentoo.org> <20250121-03-k1-gpio-v4-1-4641c95c0194@gentoo.org> <20250123113042-GYA38135@gentoo> <20250127181726.GA538260-robh@kernel.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20250127181726.GA538260-robh@kernel.org> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250127_191725_445000_7C3C0664 X-CRM114-Status: GOOD ( 46.92 ) X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: devicetree@vger.kernel.org, Conor Dooley , Meng Zhang , linux-gpio@vger.kernel.org, Linus Walleij , linux-kernel@vger.kernel.org, Conor Dooley , Yangyu Chen , linux-riscv@lists.infradead.org, Palmer Dabbelt , Jesse Taube , Jisheng Zhang , Paul Walmsley , Olof Johansson , Inochi Amaoto , Krzysztof Kozlowski , Bartosz Golaszewski Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org Hi Rob: On 12:17 Mon 27 Jan , Rob Herring wrote: > On Thu, Jan 23, 2025 at 03:19:18PM -0800, Olof Johansson wrote: > > On Thu, Jan 23, 2025 at 11:30:42AM +0000, Yixun Lan wrote: > > > Hi Olof: > > > thanks for your reivew > > > > > > On 12:03 Wed 22 Jan , Olof Johansson wrote: > > > > Hi, > > > > > > > > On Tue, Jan 21, 2025 at 11:38:11AM +0800, Yixun Lan wrote: > > > > > The GPIO controller of K1 support basic functions as input/output, > > > > > all pins can be used as interrupt which route to one IRQ line, > > > > > trigger type can be select between rising edge, failing edge, or both. > > > > > There are four GPIO ports, each consisting of 32 pins. > > > > > > > > > > Signed-off-by: Yixun Lan > > > > > --- > > > > > .../devicetree/bindings/gpio/spacemit,k1-gpio.yaml | 116 +++++++++++++++++++++ > > > > > 1 file changed, 116 insertions(+) > > > > > > > > > > diff --git a/Documentation/devicetree/bindings/gpio/spacemit,k1-gpio.yaml b/Documentation/devicetree/bindings/gpio/spacemit,k1-gpio.yaml > > > > > new file mode 100644 > > > > > index 0000000000000000000000000000000000000000..dd9459061aecfcba84e6a3c5052fbcddf6c61150 > > > > > --- /dev/null > > > > > +++ b/Documentation/devicetree/bindings/gpio/spacemit,k1-gpio.yaml > > > > > @@ -0,0 +1,116 @@ > > > > > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) > > > > > +%YAML 1.2 > > > > > +--- > > > > > +$id: http://devicetree.org/schemas/gpio/spacemit,k1-gpio.yaml# > > > > > +$schema: http://devicetree.org/meta-schemas/core.yaml# > > > > > + > > > > > +title: SpacemiT K1 GPIO controller > > > > > + > > > > > +maintainers: > > > > > + - Yixun Lan > > > > > + > > > > > +description: > > > > > + The controller's registers are organized as sets of eight 32-bit > > > > > + registers with each set of port controlling 32 pins. A single > > > > > + interrupt line is shared for all of the pins by the controller. > > > > > + Each port will be represented as child nodes with the generic > > > > > + GPIO-controller properties in this bindings file. > > > > > > > > There's only one interrupt line for all ports, but you have a binding that > > > > duplicates them for every set of ports. That seems overly complicated, > > > > doesn't it? They'd all bind the same handler, so there's no benefit in > > > > providing the flexibility,. > > > > > > > yes, all ports share same interrupt line, but each port has its own > > > irq related handling register, so it make sense to describe as per gpio irqchip > > > > > > also see comments below > > > > > > > > +properties: > > > > > + $nodename: > > > > > + pattern: "^gpio@[0-9a-f]+$" > > > > > + > > > > > + compatible: > > > > > + const: spacemit,k1-gpio > > > > > + > > > > > + reg: > > > > > + maxItems: 1 > > > > > + > > > > > + "#address-cells": > > > > > + const: 1 > > > > > + > > > > > + "#size-cells": > > > > > + const: 0 > > > > > + > > > > > +patternProperties: > > > > > + "^gpio-port@[0-9a-f]+$": > > > > > + type: object > > > > > + properties: > > > > > + compatible: > > > > > + const: spacemit,k1-gpio-port > > > > > + > > > > > + reg: > > > > > + maxItems: 1 > > > > > + > > > > > + gpio-controller: true > > > > > + > > > > > + "#gpio-cells": > > > > > + const: 2 > > > > > + > > > > > + gpio-ranges: true > > > > > + > > > > > + interrupts: > > > > > + maxItems: 1 > > > > > + > > > > > + interrupt-controller: true > > > > > + > > > > > + "#interrupt-cells": > > > > > + const: 2 > > > > > + description: > > > > > + The first cell is the GPIO number, the second should specify interrupt > > > > > + flag. The controller does not support level interrupts, so flags of > > > > > + IRQ_TYPE_LEVEL_HIGH, IRQ_TYPE_LEVEL_LOW should not be used. > > > > > + Refer for valid flags. > > > > > > > > Same here, since there's no real flexibility between the banks, it might > > > > make sense to consider a 3-cell GPIO specifier instead, and having > > > how to handle the fourth gpio port? I would like to have uniform driver for all ports > > > > > > > the first cell indicate bank. I could see this argument go in either > > > > direction, but I'm not sure I understand why to provide a gpio-controller > > > > per bank. > > > > > > > > > > IIUC, your suggestion here was same as the implementation of patch v3 of this driver[1], > > > while combining all four ports into one irqchip, which NACKed by maintainer[2]. > > > I tend to agree having a gpio-controller per bank provide more flexibility, > > > easy to leverage generic gpio framework, even each port can be disabled or enabled, > > > and IMO having shared irq handler isn't really a problem.. > > > > > > [1] https://lore.kernel.org/r/20241225-03-k1-gpio-v3-0-27bb7b441d62@gentoo.org > > > [2] https://lore.kernel.org/r/CACRpkdZPD2C2iPwOX_kW1Ug8jVkdHhhc7iFycHtzj5LQ0XWNgQ@mail.gmail.com > > > https://lore.kernel.org/r/CACRpkdYgGho=VQabonq4HccEiXBH2qM76K45oDaV1Jyi0xZ-YA@mail.gmail.com > > > > Hmm, I don't understand the reasoning there, but it's not my subsystem. > > > > It seems worse to me to misdescribe the hardware as separate blocks > > with a device-tree binding that no longer describes the actual hardware, > > but it's not up to me. > > I agree. It's clearly 1 block given the first 3 banks are interleaved. > yes, it's kind of weird hardware design, the first 3 gpio are register interleaved, while the 4th has independent space > If Linux can't handle 1 node for N gpio_chip's, then that's a Linux > problem. Maybe it can, IDK. I haven't seen somthing like this to register 1 node for multi gpio_chips.. To gpio/pinctrl maintainer (Linus Walleij), do you have suggestion on this? >The lookup from a DT node to gpio_chip just > needs to match on more than just DT node pointer, but look at the node > ptr and arg cells. > IIUC, are you suggesting to add a index cells to match additional gpio bank? so the underlying driver can still register 4 gpio chips? gpio: gpio@d4019000 { compatible = "spacemit,k1-gpio"; reg = <0x0 0xd4019000 0x0 0x800>; interrupt-controller; #interrupt-cells = <3>; // additional cell gpio-controller; #gpio-cells = <3>; // additional cell ... }; on comsumer side, it will be something like this: gpios = <&gpio INDEX0 0 GPIO_ACTIVE_HIGH>; interrupts = <&gpio INDEX0 0 IRQ_TYPE_EDGE_RISING>; (INDEX0 possiblely can be numeric vale (0, 1, 2, 3) or register base: 0x0 0x4 0x8 0x100) one thing I'm not sure about how to map the pinctrl pins via "gpio-ranges" to each gpio_chip, currently, in v4 verion, this info is populated via sub node of gpios (port1, port2 ...) I will investigate more on this.. but need suggestion to know if I proceed at right direction -- Yixun Lan (dlan) Gentoo Linux Developer GPG Key ID AABEFD55 _______________________________________________ linux-riscv mailing list linux-riscv@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-riscv