From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3603D2D7398; Tue, 11 Nov 2025 09:43:43 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762854224; cv=none; b=agMm57MKvgtp3Lb0gS/pzb3KZHYEaITaULVHZwd7Te+aezP7B1f/vBAk7Fve8xUinlpASgpMmaM6fiCwkwWR26FfMEVn2dTAkvVEPtAg/xHSoMrvRXDi1NMPTUgGSP7lUB7LoKEI/QnNRrfFbvAXlC0WWcG1V3UfvL/MWfBsjeg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762854224; c=relaxed/simple; bh=FAbNcGdRZ2BZlL+XAx4i735Jgte5T1dqnEhNRQbrtKg=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=nCSRPKgrS4fqX2nUvWuKtK/684cVPU2CeiYzWZrecDsBeUOfPFUjHPrcxazuA93QI+7YANOfpV/9wzCU9ln5V3qmN3UtzsdX+SLXy7dV6ces5OLEJb4cHD5zVmZRvoaomtZ85UxDzROjlbu5m8t5VDC7gBe0K/9KStHh9x3HbmE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=fSTDKRfu; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="fSTDKRfu" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6632CC2BCB2; Tue, 11 Nov 2025 09:43:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1762854223; bh=FAbNcGdRZ2BZlL+XAx4i735Jgte5T1dqnEhNRQbrtKg=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=fSTDKRfuBoKKqQLAI4vv9CnzsAbsMMVdKlRVNShFLwRD6Lu/3UM7GgEwGKA6cG9oO jgVJ3d0PU3g+tIbuujq/XnNQTRLIAxBesPj+mtvUqoFZNUJBPWCCNYkFPgIf0W2NOP YV/wEKRbtVFZZoVKVyy7iT2yFHBlMhWjAcs3jcYQWXhPEMc6fHiCrVRijyZeZOPaK7 SPdrD8fKGJO8b096aUTc1LMgHGrWucgoR9W2qazVqiJ29+fa/oa5OnHX7OzWlV6I0k wcdqSGruTUFH+wNUKzJwDy/VgsBdSpFMplFJrzsKoeIEX3f6/l2X80a7Rd93YV8Svw NpnPgdUV1GGsw== Message-ID: Date: Tue, 11 Nov 2025 10:43:38 +0100 Precedence: bulk X-Mailing-List: devicetree@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 2/2] clocksource: Add Realtek systimer as tick broadcast driver To: Hao-Wen Ting , daniel.lezcano@linaro.org, tglx@linutronix.de Cc: jinn.cheng@realtek.com, edwardwu@realtek.com, phelic@realtek.com, shawn.huang724@realtek.com, cy.huang@realtek.com, james.tai@realtek.com, cylee12@realtek.com, phinex@realtek.com, conor+dt@kernel.org, krzk+dt@kernel.org, robh@kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org References: <20251111092959.616089-1-haowen.ting@realtek.com> <20251111092959.616089-3-haowen.ting@realtek.com> From: Krzysztof Kozlowski Content-Language: en-US Autocrypt: addr=krzk@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 7bit On 11/11/2025 10:29, Hao-Wen Ting wrote: > Add a tick broadcast timer driver for Realtek SoCs. > > On Realtek platforms, CPUs can enter deep idle states (C-states) where > the local timer is stopped and powered off. Without a global tick > broadcast timer, one CPU must remain awake to wake up the others, > preventing all CPUs from entering deep idle simultaneously. > > This driver provides a tick broadcast timer which remains active > during deep idle states. This allows all CPUs to enter power-cut > idle states simultaneously, significantly reducing overall power > consumption. > > The timer operates at 1MHz and supports oneshot mode. > > Signed-off-by: Hao-Wen Ting > --- > MAINTAINERS | 5 + > drivers/clocksource/Kconfig | 10 ++ > drivers/clocksource/Makefile | 1 + > drivers/clocksource/timer-realtek.c | 173 ++++++++++++++++++++++++++++ > 4 files changed, 189 insertions(+) > create mode 100644 drivers/clocksource/timer-realtek.c > > diff --git a/MAINTAINERS b/MAINTAINERS > index c7a116b795d5..59dfd7543c39 100644 > --- a/MAINTAINERS > +++ b/MAINTAINERS > @@ -28395,3 +28395,8 @@ S: Buried alive in reporters > T: git git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git > F: * > F: */ > + > +REALTEK SYSTIMER DRIVER Why are you adding to the end of the file? Did you look at this file at all before changing this? > +M: Hao-Wen Ting > +S: Maintained > +F: drivers/clocksource/timer-realtek.c > diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig > index ffcd23668763..e86905378f82 100644 > --- a/drivers/clocksource/Kconfig > +++ b/drivers/clocksource/Kconfig > @@ -782,4 +782,14 @@ config NXP_STM_TIMER > Enables the support for NXP System Timer Module found in the > s32g NXP platform series. > > +config RTK_SYSTIMER > + bool "Realtek SYSTIMER support" > + depends on OF Missing depends on ARCH. Please don't send drivers which do not have any possible user. > + select TIMER_OF > + help > + This enables the global tick-broadcast timer on Realtek platforms. > + If your Realtek platform supports power-cut level CPU idle states, > + enabling this timer allows all CPUs to enter power-cut simultaneously > + to achieve lower power consumption. > + ... > + > +static int __init rtk_systimer_init(struct device_node *node) > +{ > + int ret; > + > + ret = timer_of_init(node, &_to); > + if (ret) > + return ret; > + > + systimer_base = timer_of_base(&_to); > + clockevents_config_and_register(&_to.clkevt, SYSTIMER_RATE, > + SYSTIMER_MIN_DELTA, SYSTIMER_MAX_DELTA); > + > + pr_info("Realtek SYSTIMER registered\n"); Drop. This does not look like useful printk message. Drivers should be silent on success: https://elixir.bootlin.com/linux/v6.15-rc7/source/Documentation/process/coding-style.rst#L913 https://elixir.bootlin.com/linux/v6.15-rc7/source/Documentation/process/debugging/driver_development_debugging_guide.rst#L79 > + return 0; > +} > + > +TIMER_OF_DECLARE(rtk_systimer, "realtek,systimer", rtk_systimer_init); Best regards, Krzysztof