From: Johan Hovold <johan@kernel.org>
To: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Cc: Johan Hovold <johan+linaro@kernel.org>,
Alexandre Belloni <alexandre.belloni@bootlin.com>,
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 16/24] rtc: pm8xxx: add support for nvmem offset
Date: Fri, 27 Jan 2023 16:32:18 +0100 [thread overview]
Message-ID: <Y9PugpnzsqZpzSGE@hovoldconsulting.com> (raw)
In-Reply-To: <85481368-b32e-61aa-f83a-fb42d58c351a@linaro.org>
On Fri, Jan 27, 2023 at 02:13:21PM +0000, Srinivas Kandagatla wrote:
> On 26/01/2023 14:20, 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 Epoch in an nvmem cell
> > so that the RTC time can be set on such platforms.
> >
> > Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
> > ---
> > drivers/rtc/rtc-pm8xxx.c | 134 +++++++++++++++++++++++++++++++++++----
> > 1 file changed, 123 insertions(+), 11 deletions(-)
> >
> > diff --git a/drivers/rtc/rtc-pm8xxx.c b/drivers/rtc/rtc-pm8xxx.c
> > index 922aef0f0241..09816b9f6282 100644
> > --- a/drivers/rtc/rtc-pm8xxx.c
> > +++ b/drivers/rtc/rtc-pm8xxx.c
> > @@ -3,6 +3,7 @@
> > */
> > +static int pm8xxx_rtc_read_nvmem_offset(struct pm8xxx_rtc *rtc_dd)
> > +{
> > + size_t len;
> > + void *buf;
> > + int rc;
> > +
> > + buf = nvmem_cell_read(rtc_dd->nvmem_cell, &len);
> > + if (IS_ERR(buf)) {
> > + rc = PTR_ERR(buf);
> > + dev_err(rtc_dd->dev, "failed to read nvmem offset: %d\n", rc);
> > + return rc;
> > + }
> > +
> > + if (len != sizeof(u32)) {
> > + dev_err(rtc_dd->dev, "unexpected nvmem cell size %zu\n", len);
> > + kfree(buf);
> > + return -EINVAL;
> > + }
> how about us nvmem_cell_read_u32()
I considered that, but did not like the asymmetry of the interface.
Specifically, nvmem_cell_read_u32() would go out and look up the nvmem
cell again even though I already have and need a reference for
nvmem_cell_write().
nvmem_cell_read_u32() seems to be a better fit as a convenience wrapper
for drivers that only need to do a single read at probe.
Johan
next prev parent reply other threads:[~2023-01-27 15:32 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 [this message]
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
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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