Re: [PATCH v3 4/5] pinctrl: freescale: add the LX2160A RCW pad-mux driver

[Frank Li <Frank.li@oss.nxp.com>]

On Sun, Nov 08, 2026 at 11:06:52AM +0100, Vincent Jardin via B4 Relay wrote:
> From: Vincent Jardin <vjardin@free.fr>
>
> The LX2160A muxes its IIC, XSPI, SDHC, UART, IRQ and EVT pads from
> fields of the RCW, read-only in RCWSR12..14 of DCFG and changed at
> runtime through the same fields of the override registers in its DCSR
> view, which read 0 until written.
>
> Since commit 8a1365c7bbc1 ("arm64: dts: lx2160a: add pinmux and i2c
> gpio to support bus recovery") Linux drives them with pinctrl-single on
> the override registers, so its first pin state clears every other field
> of the word: a board whose RCW programs a non-zero pad mux loses those
> pads at the first I2C probe.
>
> Add a driver for the pad mux as a child of the DCFG node: the fields
> of RCWSR12..14 and their encoding.
> Then pin states select them with the generic function and groups
> properties, and every change goes through the RCW override
> of fsl-guts, which reads the status register, writes the override and
> waits for the status register to follow.
>
> Signed-off-by: Vincent Jardin <vjardin@free.fr>
> ---
>  MAINTAINERS                                 |   7 +
>  drivers/pinctrl/freescale/Kconfig           |  15 ++
>  drivers/pinctrl/freescale/Makefile          |   1 +
>  drivers/pinctrl/freescale/pinctrl-lx2160a.c | 355 ++++++++++++++++++++++++++++
>  4 files changed, 378 insertions(+)
>
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 93abbb315065..6c488605f5da 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -20207,6 +20207,13 @@ F:	Documentation/devicetree/bindings/clock/*imx*
>  F:	drivers/clk/imx/
>  F:	include/dt-bindings/clock/*imx*
>
> +NXP LX2160A RCW PAD-MUX DRIVER
> +M:	Vincent Jardin <vjardin@free.fr>
> +L:	linux-gpio@vger.kernel.org

Add imx@lists.linux.dev

> +S:	Maintained
> +F:	Documentation/devicetree/bindings/pinctrl/fsl,lx2160a-rcw-pinmux.yaml
> +F:	drivers/pinctrl/freescale/pinctrl-lx2160a.c
> +
>  NXP NETC ETHERNET SWITCH DRIVER
>  M:	Wei Fang <wei.fang@nxp.com>
>  R:	Clark Wang <xiaoning.wang@nxp.com>
> diff --git a/drivers/pinctrl/freescale/Kconfig b/drivers/pinctrl/freescale/Kconfig
> index fd53cf5bb843..a3222714c970 100644
> --- a/drivers/pinctrl/freescale/Kconfig
> +++ b/drivers/pinctrl/freescale/Kconfig
> @@ -283,3 +283,18 @@ config PINCTRL_IMXRT1170
>  	select PINCTRL_IMX
>  	help
>  	  Say Y here to enable the imxrt1170 pinctrl driver
> +
> +config PINCTRL_LX2160A
> +	bool "NXP LX2160A RCW pad-mux driver"
> +	depends on OF
> +	depends on ARCH_LAYERSCAPE || COMPILE_TEST
> +	default ARCH_LAYERSCAPE
> +	select FSL_GUTS
> +	select GENERIC_PINCTRL_GROUPS
> +	select GENERIC_PINMUX_FUNCTIONS
> +	select GENERIC_PINCONF
> +	help
> +	  Say Y here to mux the IIC, XSPI, SDHC, UART, IRQ and EVT pads of the
> +	  LX2160A at runtime. The pads are muxed by fields of the RCW:
> +	  the driver changes it in the DCSR view of the DCFG that fsl-guts
> +	  drives, and is what the I2C bus recovery of the LX2160A needs.
> diff --git a/drivers/pinctrl/freescale/Makefile b/drivers/pinctrl/freescale/Makefile
> index d27085c2b4c4..5ec0d1710ad5 100644
> --- a/drivers/pinctrl/freescale/Makefile
> +++ b/drivers/pinctrl/freescale/Makefile
> @@ -35,3 +35,4 @@ obj-$(CONFIG_PINCTRL_IMX25)	+= pinctrl-imx25.o
>  obj-$(CONFIG_PINCTRL_IMX28)	+= pinctrl-imx28.o
>  obj-$(CONFIG_PINCTRL_IMXRT1050)	+= pinctrl-imxrt1050.o
>  obj-$(CONFIG_PINCTRL_IMXRT1170)	+= pinctrl-imxrt1170.o
> +obj-$(CONFIG_PINCTRL_LX2160A)	+= pinctrl-lx2160a.o
> diff --git a/drivers/pinctrl/freescale/pinctrl-lx2160a.c b/drivers/pinctrl/freescale/pinctrl-lx2160a.c
> new file mode 100644
> index 000000000000..ba5bbcfab9fd
> --- /dev/null
> +++ b/drivers/pinctrl/freescale/pinctrl-lx2160a.c
> @@ -0,0 +1,355 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * LX2160A pad muxes: fields of the RCW, changed at
> + * runtime.
> + *
> + * Copyright 2026 Free Mobile - Vincent Jardin
> + */
> +
> +#include <linux/bits.h>
> +#include <linux/fsl/guts.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/pinctrl/pinconf-generic.h>
> +#include <linux/pinctrl/pinctrl.h>
> +#include <linux/pinctrl/pinmux.h>
> +#include <linux/platform_device.h>
> +#include <linux/seq_file.h>
> +
> +#include "../core.h"
> +#include "../pinmux.h"
> +
> +struct lx2160a_pmux_func {
> +	const char *name;
> +	u8 val;
> +};
> +
> +struct lx2160a_pmux_group {
> +	const char *name;
> +	u8 rcwsr; /* 12..14 */
> +	u8 shift;
> +	u8 width;
> +	const struct lx2160a_pmux_func *funcs;
> +	u8 nfuncs;
> +};
> +
> +#define FUNC(_name, _val)	{ .name = _name, .val = _val }
> +#define GROUP(_name, _rcwsr, _shift, _width, _funcs)			\

The name is too common and short, easy happen name collision.

Frank