RE: [PATCH v2 02/11] mfd: renesas-vbattb: Add a MFD driver for the Renesas VBATTB IP

[Biju Das]

Hi Claudiu,

> -----Original Message-----
> From: Claudiu <claudiu.beznea@xxxxxxxxx>
> Sent: Tuesday, July 16, 2024 11:30 AM
> Subject: [PATCH v2 02/11] mfd: renesas-vbattb: Add a MFD driver for the Renesas VBATTB IP
> 
> From: Claudiu Beznea <claudiu.beznea.uj@xxxxxxxxxxxxxx>
> 
> Renesas VBATTB IP has logic to control the RTC clock, tamper detection and a small 128B memory. Add a
> MFD driver to do the basic initialization of the VBATTB IP for the inner components to work.
> 
> Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@xxxxxxxxxxxxxx>
> ---
> 
> Changes in v2:
> - none; this driver is new
> 
>  drivers/mfd/Kconfig          |  8 ++++
>  drivers/mfd/Makefile         |  1 +
>  drivers/mfd/renesas-vbattb.c | 78 ++++++++++++++++++++++++++++++++++++
>  3 files changed, 87 insertions(+)
>  create mode 100644 drivers/mfd/renesas-vbattb.c
> 
> diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig index bc8be2e593b6..df93e8b05065 100644
> --- a/drivers/mfd/Kconfig
> +++ b/drivers/mfd/Kconfig
> @@ -1383,6 +1383,14 @@ config MFD_SC27XX_PMIC
>  	  This driver provides common support for accessing the SC27xx PMICs,
>  	  and it also adds the irq_chip parts for handling the PMIC chip events.
> 
> +config MFD_RENESAS_VBATTB
> +	tristate "Renesas VBATTB driver"
> +	depends on (ARCH_RZG2L && OF) || COMPILE_TEST
> +	select MFD_CORE
> +	help
> +	  Select this option to enable Renesas RZ/G3S VBATTB driver which
> +	  provides support for the RTC clock, tamper detector and 128B SRAM.
> +
>  config RZ_MTU3
>  	tristate "Renesas RZ/G2L MTU3a core driver"
>  	depends on (ARCH_RZG2L && OF) || COMPILE_TEST diff --git a/drivers/mfd/Makefile
> b/drivers/mfd/Makefile index 02b651cd7535..cd2f27492df2 100644
> --- a/drivers/mfd/Makefile
> +++ b/drivers/mfd/Makefile
> @@ -186,6 +186,7 @@ pcf50633-objs			:= pcf50633-core.o pcf50633-irq.o
>  obj-$(CONFIG_MFD_PCF50633)	+= pcf50633.o
>  obj-$(CONFIG_PCF50633_ADC)	+= pcf50633-adc.o
>  obj-$(CONFIG_PCF50633_GPIO)	+= pcf50633-gpio.o
> +obj-$(CONFIG_MFD_RENESAS_VBATTB)	+= renesas-vbattb.o
>  obj-$(CONFIG_RZ_MTU3)		+= rz-mtu3.o
>  obj-$(CONFIG_ABX500_CORE)	+= abx500-core.o
>  obj-$(CONFIG_MFD_DB8500_PRCMU)	+= db8500-prcmu.o
> diff --git a/drivers/mfd/renesas-vbattb.c b/drivers/mfd/renesas-vbattb.c new file mode 100644 index
> 000000000000..5d71565b8cbf
> --- /dev/null
> +++ b/drivers/mfd/renesas-vbattb.c
> @@ -0,0 +1,78 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * VBATTB driver
> + *
> + * Copyright (C) 2024 Renesas Electronics Corp.
> + */
> +
> +#include <linux/mod_devicetable.h>
> +#include <linux/of_platform.h>
> +#include <linux/platform_device.h>
> +#include <linux/pm_runtime.h>
> +#include <linux/reset.h>
> +
> +static int vbattb_probe(struct platform_device *pdev) {
> +	struct device *dev = &pdev->dev;
> +	struct reset_control *rstc;
> +	int ret;
> +
> +	rstc = devm_reset_control_array_get_exclusive(dev);
> +	if (IS_ERR(rstc))
> +		return PTR_ERR(rstc);
> +
> +	ret = devm_pm_runtime_enable(dev);
> +	if (ret)
> +		return ret;
> +
> +	ret = pm_runtime_resume_and_get(dev);
> +	if (ret)
> +		return ret;

Maybe as an optimization drop pm calls and use "devm_clk_get_enabled"
instead as it perfectly fits in this scenario??

> +
> +	ret = reset_control_deassert(rstc);
> +	if (ret)
> +		goto rpm_put;
> +
> +	platform_set_drvdata(pdev, rstc);
> +
> +	ret = devm_of_platform_populate(dev);
> +	if (ret)
> +		goto reset_assert;
> +
> +	return 0;
> +
> +reset_assert:
> +	reset_control_assert(rstc);
> +rpm_put:
> +	pm_runtime_put(dev);
> +	return ret;
> +}
> +
> +static void vbattb_remove(struct platform_device *pdev) {
> +	struct reset_control *rstc = platform_get_drvdata(pdev);
> +
> +	reset_control_assert(rstc);
> +	pm_runtime_put(&pdev->dev);
> +}
> +
> +static const struct of_device_id vbattb_match[] = {
> +	{ .compatible = "renesas,r9a08g045-vbattb" },
> +	{ /* sentinel */ },
> +};
> +MODULE_DEVICE_TABLE(of, vbattb_match);
> +
> +static struct platform_driver vbattb_driver = {
> +	.probe = vbattb_probe,
> +	.remove_new = vbattb_remove,
> +	.driver = {
> +		.name = "renesas-vbattb",
> +		.of_match_table = vbattb_match,
> +	},
> +};
> +module_platform_driver(vbattb_driver);
> +
> +MODULE_ALIAS("platform:renesas-vbattb");
> +MODULE_AUTHOR("Claudiu Beznea <claudiu.beznea.uj@xxxxxxxxxxxxxx>");
> +MODULE_DESCRIPTION("Renesas VBATTB driver"); MODULE_LICENSE("GPL");
> --
> 2.39.2
>