From: Alexandre Belloni <alexandre.belloni@bootlin.com>
To: Johan Hovold <johan@kernel.org>
Cc: Johan Hovold <johan+linaro@kernel.org>,
Bjorn Andersson <andersson@kernel.org>,
Andy Gross <agross@kernel.org>,
Konrad Dybcio <konrad.dybcio@linaro.org>,
Alessandro Zummo <a.zummo@towertech.it>,
Rob Herring <robh+dt@kernel.org>,
Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
Maximilian Luz <luzmaximilian@gmail.com>,
linux-arm-msm@vger.kernel.org, linux-rtc@vger.kernel.org,
devicetree@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 19/24] rtc: pm8xxx: add support for uefi offset
Date: Fri, 27 Jan 2023 16:59:10 +0100 [thread overview]
Message-ID: <Y9P0zuovXqBbFSLs@mail.local> (raw)
In-Reply-To: <Y9PtIiD1o8eBq2wk@hovoldconsulting.com>
On 27/01/2023 16:26:26+0100, Johan Hovold wrote:
> On Fri, Jan 27, 2023 at 04:19:18PM +0100, Alexandre Belloni wrote:
> > On 26/01/2023 15:20:52+0100, Johan Hovold wrote:
> > > On many Qualcomm platforms the PMIC RTC control and time registers are
> > > read-only so that the RTC time can not be updated. Instead an offset
> > > needs be stored in some machine-specific non-volatile memory, which the
> > > driver can take into account.
> > >
> > > Add support for storing a 32-bit offset from the GPS time epoch in a
> > > UEFI variable so that the RTC time can be set on such platforms.
> > >
> >
> > Why are you using the GPS epoch? This seems pretty random.
>
> Tell that to the Qualcomm firmware team. ;)
>
> Perhaps I could have made it more clear, but this is the format that the
> firmware uses so Linux is not free to pick a different base here (or
> time would differ ten years between UEFI/Windows and Linux).
I expected this answer so please add this to the commit message, this
will be the fifth epoch we ave to handle then...
>
> > > The UEFI variable is
> > >
> > > 882f8c2b-9646-435f-8de5-f208ff80c1bd-RTCInfo
> > >
> > > and holds a 12-byte structure where the first four bytes is a GPS time
> > > offset in little-endian byte order.
>
> Johan
--
Alexandre Belloni, co-owner and COO, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com
next prev parent reply other threads:[~2023-01-27 15:59 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-26 14:20 [PATCH 00/24] rtc: pm8xxx: add support for setting time using nvmem Johan Hovold
2023-01-26 14:20 ` [PATCH 01/24] rtc: pm8xxx: fix set-alarm race Johan Hovold
2023-01-26 14:20 ` [PATCH 02/24] rtc: pm8xxx: drop spmi error messages Johan Hovold
2023-01-26 14:20 ` [PATCH 03/24] rtc: pm8xxx: use regmap_update_bits() Johan Hovold
2023-01-26 14:20 ` [PATCH 04/24] rtc: pm8xxx: drop bogus locking Johan Hovold
2023-01-26 14:20 ` [PATCH 05/24] rtc: pm8xxx: return IRQ_NONE on errors Johan Hovold
2023-01-26 14:20 ` [PATCH 06/24] rtc: pm8xxx: drop unused register defines Johan Hovold
2023-01-26 14:20 ` [PATCH 07/24] rtc: pm8xxx: use unaligned le32 helpers Johan Hovold
2023-01-26 14:20 ` [PATCH 08/24] rtc: pm8xxx: clean up time and alarm debugging Johan Hovold
2023-01-26 14:20 ` [PATCH 09/24] rtc: pm8xxx: rename struct device pointer Johan Hovold
2023-01-26 14:20 ` [PATCH 10/24] rtc: pm8xxx: rename alarm irq variable Johan Hovold
2023-01-26 14:20 ` [PATCH 11/24] rtc: pm8xxx: clean up comments Johan Hovold
2023-01-26 14:20 ` [PATCH 12/24] rtc: pm8xxx: use u32 for timestamps Johan Hovold
2023-01-26 14:20 ` [PATCH 13/24] rtc: pm8xxx: refactor read_time() Johan Hovold
2023-01-26 14:20 ` [PATCH 14/24] rtc: pm8xxx: clean up local declarations Johan Hovold
2023-01-26 14:20 ` [PATCH 15/24] dt-bindings: rtc: qcom-pm8xxx: add nvmem-cell offset Johan Hovold
2023-01-26 15:56 ` Krzysztof Kozlowski
2023-01-26 14:20 ` [PATCH 16/24] rtc: pm8xxx: add support for nvmem offset Johan Hovold
2023-01-27 14:13 ` Srinivas Kandagatla
2023-01-27 15:32 ` Johan Hovold
2023-01-27 15:09 ` Alexandre Belloni
2023-01-27 15:51 ` Johan Hovold
2023-01-27 16:05 ` Alexandre Belloni
2023-02-02 15:12 ` Johan Hovold
2023-02-02 15:21 ` Alexandre Belloni
2023-01-26 14:20 ` [PATCH 17/24] rtc: pm8xxx: add copyright notice Johan Hovold
2023-01-26 16:06 ` Alexandre Belloni
2023-01-27 13:04 ` Johan Hovold
2023-01-27 14:14 ` Krzysztof Kozlowski
2023-02-02 10:22 ` Johan Hovold
2023-01-26 14:20 ` [RFC 18/24] dt-bindings: rtc: qcom-pm8xxx: add uefi-variable offset Johan Hovold
2023-01-30 18:49 ` Rob Herring
2023-02-01 16:09 ` Johan Hovold
2023-02-09 16:59 ` Ard Biesheuvel
2023-01-26 14:20 ` [PATCH 19/24] rtc: pm8xxx: add support for uefi offset Johan Hovold
2023-01-26 14:27 ` Johan Hovold
2023-01-27 15:19 ` Alexandre Belloni
2023-01-27 15:26 ` Johan Hovold
2023-01-27 15:59 ` Alexandre Belloni [this message]
2023-01-26 14:20 ` [PATCH 20/24] arm64: defconfig: enable Qualcomm SDAM nvmem driver Johan Hovold
2023-01-26 14:20 ` [PATCH 21/24] arm64: dts: qcom: sc8280xp-pmics: add pmk8280 rtc Johan Hovold
2023-01-26 14:20 ` [PATCH 22/24] arm64: dts: qcom: sc8280xp-pmics: add pmk8280 sdam nvram Johan Hovold
2023-01-26 14:20 ` [PATCH 23/24] arm64: dts: qcom: sc8280xp-crd: enable rtc Johan Hovold
2023-01-26 14:20 ` [PATCH 24/24] arm64: dts: qcom: sc8280xp-x13s: " Johan Hovold
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