linux-kernel - Re: [PATCH v2 5/9] drivers: gpio: add QIXIS FPGA GPIO controller

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Message-ID: <CAMRc=MeoTwyj6kV7PYGCZSqTB5dfBsoQd8byHFc2B1MHAaeYdw@mail.gmail.com>
Date: Wed, 17 Sep 2025 04:08:14 -0400
From: Bartosz Golaszewski <brgl@...ev.pl>
To: Ioana Ciornei <ioana.ciornei@....com>
Cc: Rob Herring <robh@...nel.org>, Krzysztof Kozlowski <krzk+dt@...nel.org>, 
	Conor Dooley <conor+dt@...nel.org>, Linus Walleij <linus.walleij@...aro.org>, 
	Bartosz Golaszewski <brgl@...ev.pl>, Shawn Guo <shawnguo@...nel.org>, Michael Walle <mwalle@...nel.org>, 
	Lee Jones <lee@...nel.org>, devicetree@...r.kernel.org, linux-gpio@...r.kernel.org, 
	linux-kernel@...r.kernel.org, Frank Li <Frank.li@....com>
Subject: Re: [PATCH v2 5/9] drivers: gpio: add QIXIS FPGA GPIO controller

On Wed, 17 Sep 2025 09:40:37 +0200, Ioana Ciornei <ioana.ciornei@....com> said:
> On Tue, Sep 16, 2025 at 12:39:02PM -0400, Frank Li wrote:
>> On Mon, Sep 15, 2025 at 03:23:50PM +0300, Ioana Ciornei wrote:
>> > Add support for the GPIO controller found on some QIXIS FPGAs in
>> > Layerscape boards such as LX2160ARDB and LS1046AQDS. This driver is
>> > using gpio-regmap.
>> >
>> > A GPIO controller has a maximum of 8 lines (all found in the same
>> > register). Even within the same controller, the GPIO lines' direction is
>> > fixed, which mean that both input and output lines are found in the same
>> > register. This is why the driver also passed to gpio-regmap the newly
>> > added .fixed_direction_output bitmap to represent the true direction of
>> > the lines.
>> >
>> > Signed-off-by: Ioana Ciornei <ioana.ciornei@....com>
>> > ---
>> > Changes in v2:
>> > - Use the newly added .fixed_direction_output bitmap representing
>> >   the fixed direction of the GPIO lines.
>> >
>> >  drivers/gpio/Kconfig           |   9 +++
>> >  drivers/gpio/Makefile          |   1 +
>> >  drivers/gpio/gpio-qixis-fpga.c | 123 +++++++++++++++++++++++++++++++++
>> >  3 files changed, 133 insertions(+)
>> >  create mode 100644 drivers/gpio/gpio-qixis-fpga.c
>> >
>> > diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
>> > index 886bef9106da..4ca5890007ff 100644
>> > --- a/drivers/gpio/Kconfig
>> > +++ b/drivers/gpio/Kconfig
>> > @@ -1951,6 +1951,15 @@ config GPIO_LATCH
>> >  	  Say yes here to enable a driver for GPIO multiplexers based on latches
>> >  	  connected to other GPIOs.
>> >
>> > +config GPIO_QIXIS_FPGA
>> > +	tristate "NXP QIXIS FPGA GPIO support"
>> > +	depends on MFD_SIMPLE_MFD_I2C || COMPILE_TEST
>> > +	select GPIO_REGMAP
>> > +	help
>> > +	  This enables support for the GPIOs found in the QIXIS FPGA which is
>> > +	  integrated on some NXP Layerscape boards such as LX2160ARDB and
>> > +	  LS1046AQDS.
>> > +
>> >  config GPIO_MOCKUP
>> >  	tristate "GPIO Testing Driver (DEPRECATED)"
>> >  	select IRQ_SIM
>> > diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
>> > index 379f55e9ed1e..373b1f169558 100644
>> > --- a/drivers/gpio/Makefile
>> > +++ b/drivers/gpio/Makefile
>> > @@ -144,6 +144,7 @@ obj-$(CONFIG_GPIO_PL061)		+= gpio-pl061.o
>> >  obj-$(CONFIG_GPIO_PMIC_EIC_SPRD)	+= gpio-pmic-eic-sprd.o
>> >  obj-$(CONFIG_GPIO_POLARFIRE_SOC)	+= gpio-mpfs.o
>> >  obj-$(CONFIG_GPIO_PXA)			+= gpio-pxa.o
>> > +obj-$(CONFIG_GPIO_QIXIS_FPGA)		+= gpio-qixis-fpga.o
>> >  obj-$(CONFIG_GPIO_RASPBERRYPI_EXP)	+= gpio-raspberrypi-exp.o
>> >  obj-$(CONFIG_GPIO_RC5T583)		+= gpio-rc5t583.o
>> >  obj-$(CONFIG_GPIO_RCAR)			+= gpio-rcar.o
>> > diff --git a/drivers/gpio/gpio-qixis-fpga.c b/drivers/gpio/gpio-qixis-fpga.c
>> > new file mode 100644
>> > index 000000000000..23219a634f73
>> > --- /dev/null
>> > +++ b/drivers/gpio/gpio-qixis-fpga.c
>> > @@ -0,0 +1,123 @@
>> > +// SPDX-License-Identifier: GPL-2.0-only
>> > +/*
>> > + * Layerscape GPIO QIXIS FPGA driver
>> > + *
>> > + * Copyright 2025 NXP
>> > + */
>> > +
>> > +#include <linux/device.h>
>> > +#include <linux/gpio/driver.h>
>> > +#include <linux/gpio/regmap.h>
>> > +#include <linux/kernel.h>
>> > +#include <linux/mod_devicetable.h>
>> > +#include <linux/module.h>
>> > +#include <linux/platform_device.h>
>> > +#include <linux/regmap.h>
>> > +
>> > +enum qixis_cpld_gpio_type {
>> > +	LX2160ARDB_GPIO_SFP = 0,
>> > +	LS1046AQDS_GPIO_STAT_PRES2,
>> > +};
>>
>> needn't type at all.
>>
>
> True, I can just pass the u64 bitmap directly as data. Will try.
>
> [snip]
>
>> > +	if (!pdev->dev.parent)
>> > +		return -ENODEV;
>> > +
>> > +	cfg = device_get_match_data(&pdev->dev);
>> > +	if (!cfg)
>> > +		return -ENODEV;
>>
>> Needn't this check.
>
> Ok.
>
>>
>> > +
>> > +	ret = device_property_read_u32(&pdev->dev, "reg", &base);
>> > +	if (ret)
>> > +		return ret;
>> > +
>> > +	regmap = dev_get_regmap(pdev->dev.parent, NULL);
>> > +	if (!regmap) {
>> > +		/* In case there is no regmap configured by the parent device,
>> > +		 * create our own.
>> > +		 */
>>
>> /* Use MMIO space */
>
> Ok.
>
>
> [snip]
>
>> +		config.reg_set_base = GPIO_REGMAP_ADDR(base);
>>
>>
>> only two compatibles string in qixis_cpld_gpio_of_match. so it can set
>> unconditional.
>>
>
> Fair point. Will change.
>
> Ioana
>

When sending the next revision please change the title to: "gpio: foo: ...",
IOW: drop the drivers prefix.

Bartosz