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

[claudiu beznea <claudiu.beznea@tuxon.dev>]

Hi, Biju,

On 16.07.2024 14:00, Biju Das wrote:
> Hi Claudiu,
> 
> Thanks for the patch.
> 
> 
>> -----Original Message-----
>> From: Claudiu <claudiu.beznea@tuxon.dev>
>> 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@bp.renesas.com>
>>
>> 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@bp.renesas.com>
>> ---
>>
>> 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
> 
> There is no MFD calls??  What is the purpose of selecting MFD_CORE??

I missed to remove it from here.

> 
>> +	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;
>> +
>> +	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 */ },
> 
> Drop comma.
> 
>> +};
>> +MODULE_DEVICE_TABLE(of, vbattb_match);
>> +
>> +static struct platform_driver vbattb_driver = {
>> +	.probe = vbattb_probe,
>> +	.remove_new = vbattb_remove,
> 
> Maybe remove canbe replaced with devm_add_action_or_reset()
> That simplifies probe() aswell??

This approach needs a new structure to keep references to the rstc and dev,
to be able to handle reset and runtime PM in action function. I wanted to
avoid adding a new structure.

Thank you for your review,
Claudiu Beznea

> 
>> +	.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@bp.renesas.com>");
>> +MODULE_DESCRIPTION("Renesas VBATTB driver"); MODULE_LICENSE("GPL");
>> --
>> 2.39.2
>>
>