Message ID | 20230802150545.3742-2-jszhang@kernel.org |
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State | New |
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[2620:137:e000::1:20]) by mx.google.com with ESMTP id nl18-20020a17090b385200b00267bb4cfaa7si1474569pjb.88.2023.08.02.08.49.21; Wed, 02 Aug 2023 08:49:35 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@kernel.org header.s=k20201202 header.b=WTidJq0g; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234043AbjHBPYC (ORCPT <rfc822;maxi.paulin@gmail.com> + 99 others); Wed, 2 Aug 2023 11:24:02 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43852 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235040AbjHBPWd (ORCPT <rfc822;linux-kernel@vger.kernel.org>); Wed, 2 Aug 2023 11:22:33 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E1E323AAD; Wed, 2 Aug 2023 08:19:03 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 8BC38619EF; Wed, 2 Aug 2023 15:17:30 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 771D3C433C9; Wed, 2 Aug 2023 15:17:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1690989450; bh=DXeugDAACdhg9l7C34Qgdlwo7dhx5GjmUFqTsipeB0Q=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=WTidJq0g+3RtB+rm5HDHBuJyHNkJuBE+cM9d+FiuqXRMc0gvbkVRqstZPS8wHXhG2 +1/kZ6bxbU7rvDTlM73S/oEo/55xevFUj8qni6y+tyBlkyGAPaqYSP7G+5CsD/0d8v ybvT+oKP+Klwnp+pamscqUH9b2sN5Awk+LYpTcB/2NDacKMO/yRgIIEc10ItOiqv6S VmUzf4mzYP8MdVvUV4SHJqvMRLTl/bcXmeeCoKFyxcj1ubqGqooLIsXG9qRghN+K8t /i1ncOuGcm9eR2QdsIug9MNdnbKjPZH7JtGPDrFVs10hnIy5HBUDgOWizKE5YAfwIU Ow1/bIrc8RW9A== From: Jisheng Zhang <jszhang@kernel.org> To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>, Rob Herring <robh+dt@kernel.org>, Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>, Conor Dooley <conor+dt@kernel.org>, =?utf-8?q?Ilpo_J=C3=A4rvinen?= <ilpo.jarvinen@linux.intel.com>, Andy Shevchenko <andriy.shevchenko@linux.intel.com>, Jiri Slaby <jirislaby@kernel.org> Cc: linux-serial@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 1/2] dt-bindings: serial: snps-dw-apb-uart: make interrupt optional Date: Wed, 2 Aug 2023 23:05:44 +0800 Message-Id: <20230802150545.3742-2-jszhang@kernel.org> X-Mailer: git-send-email 2.40.0 In-Reply-To: <20230802150545.3742-1-jszhang@kernel.org> References: <20230802150545.3742-1-jszhang@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF, RCVD_IN_DNSWL_BLOCKED,SPF_HELO_NONE,SPF_PASS,T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: <linux-kernel.vger.kernel.org> X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: 1773132972082059268 X-GMAIL-MSGID: 1773132972082059268 |
Series |
serial: 8250_dw: fall back to poll if there's no interrupt
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Commit Message
Jisheng Zhang
Aug. 2, 2023, 3:05 p.m. UTC
The driver fall back to poll style when there's no irq. "poll" still
looks better than no support.
Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
---
Documentation/devicetree/bindings/serial/snps-dw-apb-uart.yaml | 1 -
1 file changed, 1 deletion(-)
Comments
On Wed, Aug 02, 2023 at 11:05:44PM +0800, Jisheng Zhang wrote: > The driver fall back to poll style when there's no irq. "poll" still > looks better than no support. What is the user for this where the interrupt is not actually wired up in the hardware? > > Signed-off-by: Jisheng Zhang <jszhang@kernel.org> > --- > Documentation/devicetree/bindings/serial/snps-dw-apb-uart.yaml | 1 - > 1 file changed, 1 deletion(-) > > diff --git a/Documentation/devicetree/bindings/serial/snps-dw-apb-uart.yaml b/Documentation/devicetree/bindings/serial/snps-dw-apb-uart.yaml > index 3862411c77b5..17c553123f96 100644 > --- a/Documentation/devicetree/bindings/serial/snps-dw-apb-uart.yaml > +++ b/Documentation/devicetree/bindings/serial/snps-dw-apb-uart.yaml > @@ -117,7 +117,6 @@ properties: > required: > - compatible > - reg > - - interrupts > > unevaluatedProperties: false > > -- > 2.40.1 >
On Wed, Aug 02, 2023 at 04:43:48PM +0100, Conor Dooley wrote: > On Wed, Aug 02, 2023 at 11:05:44PM +0800, Jisheng Zhang wrote: > > The driver fall back to poll style when there's no irq. "poll" still > > looks better than no support. > > What is the user for this where the interrupt is not actually wired up > in the hardware? FYI: kernel console doesn't use interrupts, so for example it might be the debug port. Note, I have no idea of the Zhang's case, just my assumption.
On Thu, Aug 03, 2023 at 12:57:44AM +0300, Andy Shevchenko wrote: > On Wed, Aug 02, 2023 at 04:43:48PM +0100, Conor Dooley wrote: > > On Wed, Aug 02, 2023 at 11:05:44PM +0800, Jisheng Zhang wrote: > > > The driver fall back to poll style when there's no irq. "poll" still > > > looks better than no support. > > > > What is the user for this where the interrupt is not actually wired up > > in the hardware? > > FYI: kernel console doesn't use interrupts, so for example it might be > the debug port. Note, I have no idea of the Zhang's case, just my assumption. I'm less interested in what the software is doing, it's what the device that has not connected the interrupt is that I am curious about.
On Wed, Aug 02, 2023 at 11:53:59PM +0100, Conor Dooley wrote: > On Thu, Aug 03, 2023 at 12:57:44AM +0300, Andy Shevchenko wrote: > > On Wed, Aug 02, 2023 at 04:43:48PM +0100, Conor Dooley wrote: > > > On Wed, Aug 02, 2023 at 11:05:44PM +0800, Jisheng Zhang wrote: > > > > The driver fall back to poll style when there's no irq. "poll" still > > > > looks better than no support. > > > > > > What is the user for this where the interrupt is not actually wired up > > > in the hardware? > > > > FYI: kernel console doesn't use interrupts, so for example it might be > > the debug port. Note, I have no idea of the Zhang's case, just my assumption. > > I'm less interested in what the software is doing, it's what the device > that has not connected the interrupt is that I am curious about. As I said. The hw may be purely for debugging purposes (and yes, I have heard about such a hardware).
On Thu, Aug 03, 2023 at 02:40:05PM +0300, Andy Shevchenko wrote: > On Wed, Aug 02, 2023 at 11:53:59PM +0100, Conor Dooley wrote: > > On Thu, Aug 03, 2023 at 12:57:44AM +0300, Andy Shevchenko wrote: > > > On Wed, Aug 02, 2023 at 04:43:48PM +0100, Conor Dooley wrote: > > > > On Wed, Aug 02, 2023 at 11:05:44PM +0800, Jisheng Zhang wrote: > > > > > The driver fall back to poll style when there's no irq. "poll" still > > > > > looks better than no support. > > > > > > > > What is the user for this where the interrupt is not actually wired up > > > > in the hardware? > > > > > > FYI: kernel console doesn't use interrupts, so for example it might be > > > the debug port. Note, I have no idea of the Zhang's case, just my assumption. Hi Conor, Andy, Andy's assumption about the uart dedicated for debug purpose is true, since it's for log only, so no interrupt need at all. We can also see such no irq support in litex uart driver(liteuart.c) and even a 8250 variant(8250_ioc3.c). Thanks > > > > I'm less interested in what the software is doing, it's what the device > > that has not connected the interrupt is that I am curious about. > > As I said. The hw may be purely for debugging purposes (and yes, I have heard > about such a hardware). > > -- > With Best Regards, > Andy Shevchenko > >
diff --git a/Documentation/devicetree/bindings/serial/snps-dw-apb-uart.yaml b/Documentation/devicetree/bindings/serial/snps-dw-apb-uart.yaml index 3862411c77b5..17c553123f96 100644 --- a/Documentation/devicetree/bindings/serial/snps-dw-apb-uart.yaml +++ b/Documentation/devicetree/bindings/serial/snps-dw-apb-uart.yaml @@ -117,7 +117,6 @@ properties: required: - compatible - reg - - interrupts unevaluatedProperties: false