Re: [RFC PATCH v2 2/2] rtc: add driver for Marvell 88PM886 PMIC RTC

[Alexandre Belloni <alexandre.belloni@bootlin.com>]

Lee,

I'm happy taking this patch, I guess you are going to take 1/2 ?

On 12/10/2024 21:31:39+0200, Karel Balej wrote:
> RTC lives on the chip's base register page. Add the relevant register
> definitions and implement a basic set/read time functionality. Tested
> with the samsung,coreprimevelte smartphone which contains this PMIC and
> whose vendor kernel tree has also served as the sole reference for this.
> 
> Signed-off-by: Karel Balej <balejk@matfyz.cz>
> ---
> 
> Notes:
>     RFC v2:
>     - Move in the register definitions from the preceding patch and reword
>       the commit message accordingly.
>     - Rebase to v6.12-rc2.
> 
>  MAINTAINERS                 |  1 +
>  drivers/rtc/Kconfig         | 10 ++++
>  drivers/rtc/Makefile        |  1 +
>  drivers/rtc/rtc-88pm886.c   | 97 +++++++++++++++++++++++++++++++++++++
>  include/linux/mfd/88pm886.h |  9 ++++
>  5 files changed, 118 insertions(+)
>  create mode 100644 drivers/rtc/rtc-88pm886.c
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index a097afd76ded..3a15b8711041 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -13710,6 +13710,7 @@ F:	Documentation/devicetree/bindings/mfd/marvell,88pm886-a1.yaml
>  F:	drivers/input/misc/88pm886-onkey.c
>  F:	drivers/mfd/88pm886.c
>  F:	drivers/regulator/88pm886-regulator.c
> +F:	drivers/rtc/rtc-88pm886.c
>  F:	include/linux/mfd/88pm886.h
>  
>  MARVELL ARMADA 3700 PHY DRIVERS
> diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
> index 66eb1122248b..2718ea194dd4 100644
> --- a/drivers/rtc/Kconfig
> +++ b/drivers/rtc/Kconfig
> @@ -182,6 +182,16 @@ config RTC_DRV_88PM80X
>  	  This driver can also be built as a module. If so, the module
>  	  will be called rtc-88pm80x.
>  
> +config RTC_DRV_88PM886
> +	tristate "Marvell 88PM886 RTC driver"
> +	depends on MFD_88PM886_PMIC
> +	help
> +	  If you say yes here you will get support for the RTC function in the
> +	  Marvell 88PM886 chip.
> +
> +	  This driver can also be built as a module. If so, the module
> +	  will be called rtc-88pm886.
> +
>  config RTC_DRV_ABB5ZES3
>  	select REGMAP_I2C
>  	tristate "Abracon AB-RTCMC-32.768kHz-B5ZE-S3"
> diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
> index f62340ecc534..70bbce968a43 100644
> --- a/drivers/rtc/Makefile
> +++ b/drivers/rtc/Makefile
> @@ -21,6 +21,7 @@ obj-$(CONFIG_RTC_LIB_KUNIT_TEST)	+= lib_test.o
>  
>  obj-$(CONFIG_RTC_DRV_88PM80X)	+= rtc-88pm80x.o
>  obj-$(CONFIG_RTC_DRV_88PM860X)	+= rtc-88pm860x.o
> +obj-$(CONFIG_RTC_DRV_88PM886)	+= rtc-88pm886.o
>  obj-$(CONFIG_RTC_DRV_AB8500)	+= rtc-ab8500.o
>  obj-$(CONFIG_RTC_DRV_ABB5ZES3)	+= rtc-ab-b5ze-s3.o
>  obj-$(CONFIG_RTC_DRV_ABEOZ9)	+= rtc-ab-eoz9.o
> diff --git a/drivers/rtc/rtc-88pm886.c b/drivers/rtc/rtc-88pm886.c
> new file mode 100644
> index 000000000000..57e9b0a66eed
> --- /dev/null
> +++ b/drivers/rtc/rtc-88pm886.c
> @@ -0,0 +1,97 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +#include <linux/limits.h>
> +#include <linux/mod_devicetable.h>
> +#include <linux/platform_device.h>
> +#include <linux/rtc.h>
> +
> +#include <linux/mfd/88pm886.h>
> +
> +/*
> + * Time is calculated as the sum of a 32-bit read-only advancing counter and a
> + * writeable constant offset stored in the chip's spare registers.
> + */
> +
> +static int pm886_rtc_read_time(struct device *dev, struct rtc_time *tm)
> +{
> +	struct regmap *regmap = dev_get_drvdata(dev);
> +	u32 time;
> +	u32 buf;
> +	int ret;
> +
> +	ret = regmap_bulk_read(regmap, PM886_REG_RTC_SPARE1, &buf, 4);
> +	if (ret)
> +		return ret;
> +	time = buf;
> +
> +	ret = regmap_bulk_read(regmap, PM886_REG_RTC_CNT1, &buf, 4);
> +	if (ret)
> +		return ret;
> +	time += buf;
> +
> +	rtc_time64_to_tm(time, tm);
> +
> +	return 0;
> +}
> +
> +static int pm886_rtc_set_time(struct device *dev, struct rtc_time *tm)
> +{
> +	struct regmap *regmap = dev_get_drvdata(dev);
> +	u32 buf;
> +	int ret;
> +
> +	ret = regmap_bulk_read(regmap, PM886_REG_RTC_CNT1, &buf, 4);
> +	if (ret)
> +		return ret;
> +
> +	buf = rtc_tm_to_time64(tm) - buf;
> +
> +	return regmap_bulk_write(regmap, PM886_REG_RTC_SPARE1, &buf, 4);
> +}
> +
> +static const struct rtc_class_ops pm886_rtc_ops = {
> +	.read_time = pm886_rtc_read_time,
> +	.set_time = pm886_rtc_set_time,
> +};
> +
> +static int pm886_rtc_probe(struct platform_device *pdev)
> +{
> +	struct pm886_chip *chip = dev_get_drvdata(pdev->dev.parent);
> +	struct device *dev = &pdev->dev;
> +	struct rtc_device *rtc;
> +	int ret;
> +
> +	platform_set_drvdata(pdev, chip->regmap);
> +
> +	rtc = devm_rtc_allocate_device(dev);
> +	if (IS_ERR(rtc))
> +		return dev_err_probe(dev, PTR_ERR(rtc),
> +				"Failed to allocate RTC device\n");
> +
> +	rtc->ops = &pm886_rtc_ops;
> +	rtc->range_max = U32_MAX;
> +
> +	ret = devm_rtc_register_device(rtc);
> +	if (ret)
> +		return dev_err_probe(dev, ret, "Failed to register RTC device\n");
> +
> +	return 0;
> +}
> +
> +static const struct platform_device_id pm886_rtc_id_table[] = {
> +	{ "88pm886-rtc", },
> +	{ }
> +};
> +MODULE_DEVICE_TABLE(platform, pm886_rtc_id_table);
> +
> +static struct platform_driver pm886_rtc_driver = {
> +	.driver = {
> +		.name = "88pm886-rtc",
> +	},
> +	.probe = pm886_rtc_probe,
> +	.id_table = pm886_rtc_id_table,
> +};
> +module_platform_driver(pm886_rtc_driver);
> +
> +MODULE_DESCRIPTION("Marvell 88PM886 RTC driver");
> +MODULE_AUTHOR("Karel Balej <balejk@matfyz.cz>");
> +MODULE_LICENSE("GPL");
> diff --git a/include/linux/mfd/88pm886.h b/include/linux/mfd/88pm886.h
> index 133aa302e492..85eca44f39ab 100644
> --- a/include/linux/mfd/88pm886.h
> +++ b/include/linux/mfd/88pm886.h
> @@ -31,6 +31,15 @@
>  #define PM886_INT_WC			BIT(1)
>  #define PM886_INT_MASK_MODE		BIT(2)
>  
> +#define PM886_REG_RTC_CNT1		0xd1
> +#define PM886_REG_RTC_CNT2		0xd2
> +#define PM886_REG_RTC_CNT3		0xd3
> +#define PM886_REG_RTC_CNT4		0xd4
> +#define PM886_REG_RTC_SPARE1		0xea
> +#define PM886_REG_RTC_SPARE2		0xeb
> +#define PM886_REG_RTC_SPARE3		0xec
> +#define PM886_REG_RTC_SPARE4		0xed
> +#define PM886_REG_RTC_SPARE5		0xee
>  #define PM886_REG_RTC_SPARE6		0xef
>  
>  #define PM886_REG_BUCK_EN		0x08
> -- 
> 2.47.0
> 

-- 
Alexandre Belloni, co-owner and COO, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com