devicetree.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Marc Zyngier <maz@kernel.org>
To: Phil Edworthy <phil.edworthy@renesas.com>
Cc: Rob Herring <robh+dt@kernel.org>,
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
	Geert Uytterhoeven <geert+renesas@glider.be>,
	Biju Das <biju.das.jz@bp.renesas.com>,
	Daniel Lezcano <daniel.lezcano@linaro.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Mark Rutland <mark.rutland@arm.com>,
	devicetree@vger.kernel.org, linux-renesas-soc@vger.kernel.org
Subject: Re: [PATCH v3 04/12] dt-bindings: timer: arm,arch_timer:  Add optional clock and reset
Date: Tue, 03 May 2022 14:12:23 +0100	[thread overview]
Message-ID: <6fb57bcc87e091d6e88217d2b82af9da@kernel.org> (raw)
In-Reply-To: <20220503115557.53370-5-phil.edworthy@renesas.com>

On 2022-05-03 12:55, Phil Edworthy wrote:
> Some SoCs use a gated clock for the timer and the means to reset the 
> timer.
> Hence add these as optional.

The architecture is crystal clear on the subject: the counter
is in an always-on domain. Why should this be visible to SW?
Also, reseting the counter breaks the guaranteed monotonicity
we rely on.

Worse case, this belongs to the boot firmware, not the kernel,
and I don't think this should be described in the DT.

         M.

> 
> Signed-off-by: Phil Edworthy <phil.edworthy@renesas.com>
> ---
>  .../devicetree/bindings/timer/arm,arch_timer.yaml          | 7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git
> a/Documentation/devicetree/bindings/timer/arm,arch_timer.yaml
> b/Documentation/devicetree/bindings/timer/arm,arch_timer.yaml
> index df8ce87fd54b..20cd90fc7015 100644
> --- a/Documentation/devicetree/bindings/timer/arm,arch_timer.yaml
> +++ b/Documentation/devicetree/bindings/timer/arm,arch_timer.yaml
> @@ -64,6 +64,13 @@ properties:
>        CNTFRQ on all CPUs to a uniform correct value. Use of this 
> property is
>        strongly discouraged; fix your firmware unless absolutely 
> impossible.
> 
> +  clocks:
> +    description: Optional clock for the timer.
> +    maxItems: 1
> +
> +  resets:
> +    maxItems: 1
> +
>    always-on:
>      type: boolean
>      description: If present, the timer is powered through an always-on 
> power

-- 
Jazz is not dead. It just smells funny...

  parent reply	other threads:[~2022-05-03 13:12 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-05-03 11:55 [PATCH v3 00/12] Add new Renesas RZ/V2M SoC and Renesas RZ/V2M EVK support Phil Edworthy
2022-05-03 11:55 ` [PATCH v3 01/12] dt-bindings: serial: renesas,em-uart: Add RZ/V2M clock to access the registers Phil Edworthy
2022-05-04  8:06   ` Geert Uytterhoeven
2022-05-04  8:13     ` Phil Edworthy
2022-05-03 11:55 ` [PATCH v3 02/12] dt-bindings: clock: Add r9a09g011 CPG Clock Definitions Phil Edworthy
2022-05-04  8:43   ` Geert Uytterhoeven
2022-05-03 11:55 ` [PATCH v3 03/12] dt-bindings: clock: renesas,rzg2l: Document RZ/V2M SoC Phil Edworthy
2022-05-04  8:43   ` Geert Uytterhoeven
2022-05-03 11:55 ` [PATCH v3 04/12] dt-bindings: timer: arm,arch_timer: Add optional clock and reset Phil Edworthy
2022-05-03 13:11   ` Mark Rutland
2022-05-04 22:33     ` Rob Herring
2022-05-05  6:42       ` Geert Uytterhoeven
2022-05-03 13:12   ` Marc Zyngier [this message]
2022-05-03 14:22     ` Geert Uytterhoeven
2022-05-03 14:55       ` Mark Rutland
2022-05-03 15:56       ` Marc Zyngier
2022-05-04  9:05         ` Phil Edworthy
2022-05-03 11:55 ` [PATCH v3 11/12] arm64: dts: renesas: Add initial DTSI for RZ/V2M SoC Phil Edworthy
2022-05-04  8:47   ` Geert Uytterhoeven
2022-05-03 11:55 ` [PATCH v3 12/12] arm64: dts: renesas: Add initial device tree for RZ/V2M EVK Phil Edworthy
2022-05-04  8:51   ` Geert Uytterhoeven
2022-05-04  9:00     ` Phil Edworthy

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=6fb57bcc87e091d6e88217d2b82af9da@kernel.org \
    --to=maz@kernel.org \
    --cc=biju.das.jz@bp.renesas.com \
    --cc=daniel.lezcano@linaro.org \
    --cc=devicetree@vger.kernel.org \
    --cc=geert+renesas@glider.be \
    --cc=krzysztof.kozlowski+dt@linaro.org \
    --cc=linux-renesas-soc@vger.kernel.org \
    --cc=mark.rutland@arm.com \
    --cc=phil.edworthy@renesas.com \
    --cc=robh+dt@kernel.org \
    --cc=tglx@linutronix.de \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).