linux-kernel - Re: [PATCH v7 2/4] rtc: s32g: add NXP S32G2/S32G3 SoC support

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Message-ID: <Z6ZqGeswJDPTlzvo@lizhi-Precision-Tower-5810>
Date: Fri, 7 Feb 2025 15:16:25 -0500
From: Frank Li <Frank.li@....com>
To: Ciprian Costea <ciprianmarian.costea@....nxp.com>
Cc: Alexandre Belloni <alexandre.belloni@...tlin.com>,
	Rob Herring <robh@...nel.org>,
	Krzysztof Kozlowski <krzk+dt@...nel.org>,
	Conor Dooley <conor+dt@...nel.org>,
	Catalin Marinas <catalin.marinas@....com>,
	Will Deacon <will@...nel.org>, linux-rtc@...r.kernel.org,
	devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org, NXP S32 Linux <s32@....com>,
	imx@...ts.linux.dev, Christophe Lizzi <clizzi@...hat.com>,
	Alberto Ruiz <aruizrui@...hat.com>,
	Enric Balletbo <eballetb@...hat.com>,
	Bogdan Hamciuc <bogdan.hamciuc@....com>,
	Ghennadi Procopciuc <Ghennadi.Procopciuc@....com>
Subject: Re: [PATCH v7 2/4] rtc: s32g: add NXP S32G2/S32G3 SoC support

On Fri, Feb 07, 2025 at 06:38:06PM +0200, Ciprian Costea wrote:
> From: Ciprian Marian Costea <ciprianmarian.costea@....nxp.com>
>
> Add a RTC driver for NXP S32G2/S32G3 SoCs.
>
> RTC tracks clock time during system suspend. It can be a wakeup source
> for the S32G2/S32G3 SoC based boards.
>
> The RTC module from S32G2/S32G3 is not battery-powered and it is not kept
> alive during system reset.
>
> Co-developed-by: Bogdan Hamciuc <bogdan.hamciuc@....com>
> Signed-off-by: Bogdan Hamciuc <bogdan.hamciuc@....com>
> Co-developed-by: Ghennadi Procopciuc <Ghennadi.Procopciuc@....com>
> Signed-off-by: Ghennadi Procopciuc <Ghennadi.Procopciuc@....com>
> Signed-off-by: Ciprian Marian Costea <ciprianmarian.costea@....nxp.com>
> ---
>  drivers/rtc/Kconfig    |  11 ++
>  drivers/rtc/Makefile   |   1 +
>  drivers/rtc/rtc-s32g.c | 383 +++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 395 insertions(+)
>  create mode 100644 drivers/rtc/rtc-s32g.c
>
> diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
> index 0bbbf778ecfa..510dc2db745d 100644
> --- a/drivers/rtc/Kconfig
> +++ b/drivers/rtc/Kconfig
> @@ -2103,4 +2103,15 @@ config RTC_DRV_AMLOGIC_A4
>  	  This driver can also be built as a module. If so, the module
>  	  will be called "rtc-amlogic-a4".
>
> +config RTC_DRV_S32G
> +	tristate "RTC driver for S32G2/S32G3 SoCs"
> +	depends on ARCH_S32 || COMPILE_TEST
> +	depends on COMMON_CLK
> +	help
> +	  Say yes to enable RTC driver for platforms based on the
> +	  S32G2/S32G3 SoC family.
> +
> +	  This RTC module can be used as a wakeup source.
> +	  Please note that it is not battery-powered.
> +
>  endif # RTC_CLASS
> diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
> index 489b4ab07068..e4b616ecd5ce 100644
> --- a/drivers/rtc/Makefile
> +++ b/drivers/rtc/Makefile
> @@ -161,6 +161,7 @@ obj-$(CONFIG_RTC_DRV_RX8111)	+= rtc-rx8111.o
>  obj-$(CONFIG_RTC_DRV_RX8581)	+= rtc-rx8581.o
>  obj-$(CONFIG_RTC_DRV_RZN1)	+= rtc-rzn1.o
>  obj-$(CONFIG_RTC_DRV_RENESAS_RTCA3)	+= rtc-renesas-rtca3.o
> +obj-$(CONFIG_RTC_DRV_S32G)	+= rtc-s32g.o
>  obj-$(CONFIG_RTC_DRV_S35390A)	+= rtc-s35390a.o
>  obj-$(CONFIG_RTC_DRV_S3C)	+= rtc-s3c.o
>  obj-$(CONFIG_RTC_DRV_S5M)	+= rtc-s5m.o
> diff --git a/drivers/rtc/rtc-s32g.c b/drivers/rtc/rtc-s32g.c
> new file mode 100644
> index 000000000000..3244b23c533e
> --- /dev/null
> +++ b/drivers/rtc/rtc-s32g.c

...

> +
> +static int s32g_rtc_suspend(struct device *dev)
> +{
> +	struct rtc_priv *priv = dev_get_drvdata(dev);
> +	u32 apival = readl(priv->rtc_base + APIVAL_OFFSET);
> +
> +	/* RTC registers are being reset in suspend.
> +	 * Thus store standby time.
> +	 */
> +	if (check_add_overflow(priv->sleep_sec, div64_u64(apival, priv->rtc_hz),
> +			       &priv->sleep_sec)) {
> +		dev_warn(dev, "Overflow on sleep cycles occurred. Resetting to 0.\n");
> +		priv->sleep_sec = 0;
> +	}

Strange. If RTC register are reset in suspend. How do it wake up system?

Frank

> +
> +	return 0;
> +}
> +
> +static int s32g_rtc_resume(struct device *dev)
> +{
> +	struct rtc_priv *priv = dev_get_drvdata(dev);
> +
> +	return rtc_clk_src_setup(priv);
> +}
> +
> +static const struct of_device_id rtc_dt_ids[] = {
> +	{ .compatible = "nxp,s32g2-rtc", .data = &rtc_s32g2_data},
> +	{ /* sentinel */ },
> +};
> +
> +static DEFINE_SIMPLE_DEV_PM_OPS(s32g_rtc_pm_ops,
> +			 s32g_rtc_suspend, s32g_rtc_resume);
> +
> +static struct platform_driver s32g_rtc_driver = {
> +	.driver		= {
> +		.name			= "s32g-rtc",
> +		.pm				= pm_sleep_ptr(&s32g_rtc_pm_ops),
> +		.of_match_table = rtc_dt_ids,
> +	},
> +	.probe		= s32g_rtc_probe,
> +};
> +module_platform_driver(s32g_rtc_driver);
> +
> +MODULE_AUTHOR("NXP");
> +MODULE_DESCRIPTION("NXP RTC driver for S32G2/S32G3");
> +MODULE_LICENSE("GPL");
> --
> 2.45.2
>