Re: [PATCH v5 01/13] pinctrl: Add compact Nomadik pin controller

[Stephan Gerhold <stephan.gerhold@linaro.org>]

On Sun, Aug 23, 2026 at 10:39:20PM +0200, Linus Walleij wrote:
> Add the minimal pin control support needed to consume default states from
> the upstream DB8500 device trees. Resolve the nine Nomadik GPIO banks
> through nomadik-gpio-chips and apply the mux, direction, value, pull and
> low-EMI settings directly to their registers.
> 
> Only the DB8500 binding and default-state configuration needed by
> U-Boot are supported. There is no GPIO ownership or sleep-state
> handling.
> 
> Signed-off-by: Linus Walleij <linusw@kernel.org>

Reviewed-by: Stephan Gerhold <stephan.gerhold@linaro.org>

Thanks!

> ---
>  MAINTAINERS                       |   1 +
>  arch/arm/Kconfig                  |   2 +
>  drivers/pinctrl/Kconfig           |   7 ++
>  drivers/pinctrl/Makefile          |   1 +
>  drivers/pinctrl/pinctrl-nomadik.c | 230 ++++++++++++++++++++++++++++++++++++++
>  5 files changed, 241 insertions(+)
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index eb48eea55c5a..a5d6b5be29dc 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -787,6 +787,7 @@ S:	Maintained
>  F:	arch/arm/dts/ste-*
>  F:	arch/arm/mach-u8500/
>  F:	drivers/gpio/nmk_gpio.c
> +F:	drivers/pinctrl/pinctrl-nomadik.c
>  F:	drivers/phy/phy-ab8500-usb.c
>  F:	drivers/power/pmic/ab8500.c
>  F:	drivers/timer/nomadik-mtu-timer.c
> diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
> index 1b474a346bf2..5b02ff18bd0e 100644
> --- a/arch/arm/Kconfig
> +++ b/arch/arm/Kconfig
> @@ -1278,6 +1278,8 @@ config ARCH_U8500
>  	imply DM_RTC
>  	imply NOMADIK_GPIO
>  	imply NOMADIK_MTU_TIMER
> +	imply PINCTRL
> +	imply PINCTRL_NOMADIK
>  	imply PHY
>  	imply PL01X_SERIAL
>  	imply PMIC_AB8500
> diff --git a/drivers/pinctrl/Kconfig b/drivers/pinctrl/Kconfig
> index fd30aaeeaa89..04785a927fec 100644
> --- a/drivers/pinctrl/Kconfig
> +++ b/drivers/pinctrl/Kconfig
> @@ -75,6 +75,13 @@ config PINCONF_RECURSIVE
>  	  configuration; you can save memory footprint when this feature is
>  	  no needed.
>  
> +config PINCTRL_NOMADIK
> +	bool "Nomadik pin control driver"
> +	depends on PINCTRL_FULL
> +	help
> +	  Enable pin multiplexing and configuration support for the Nomadik
> +	  GPIO blocks in the ST-Ericsson DB8500.
> +
>  config SPL_PINCTRL
>  	bool "Support pin controllers in SPL"
>  	depends on SPL && SPL_DM
> diff --git a/drivers/pinctrl/Makefile b/drivers/pinctrl/Makefile
> index 91149796bb5f..23219626e392 100644
> --- a/drivers/pinctrl/Makefile
> +++ b/drivers/pinctrl/Makefile
> @@ -25,6 +25,7 @@ obj-$(CONFIG_PINCTRL_K210)		+= pinctrl-k210.o
>  obj-$(CONFIG_PINCTRL_MESON)		+= meson/
>  obj-$(CONFIG_PINCTRL_MSCC)		+= mscc/
>  obj-$(CONFIG_PINCTRL_MTK)		+= mediatek/
> +obj-$(CONFIG_PINCTRL_NOMADIK)		+= pinctrl-nomadik.o
>  obj-$(CONFIG_PINCTRL_PIC32)		+= pinctrl_pic32.o
>  obj-$(CONFIG_PINCTRL_QCOM)		+= qcom/
>  obj-$(CONFIG_PINCTRL_QE)		+= pinctrl-qe-io.o
> diff --git a/drivers/pinctrl/pinctrl-nomadik.c b/drivers/pinctrl/pinctrl-nomadik.c
> new file mode 100644
> index 000000000000..12d032226608
> --- /dev/null
> +++ b/drivers/pinctrl/pinctrl-nomadik.c
> @@ -0,0 +1,230 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/* Copyright (C) 2026 Linus Walleij <linusw@kernel.org> */
> +
> +#include <dm.h>
> +#include <dm/pinctrl.h>
> +#include <dt-bindings/pinctrl/nomadik.h>
> +#include <vsprintf.h>
> +#include <asm/io.h>
> +
> +#define NMK_GPIO_BANKS		9
> +#define NMK_GPIO_PER_BANK	32
> +
> +struct nmk_gpio_regs {
> +	u32 dat;
> +	u32 dats;
> +	u32 datc;
> +	u32 pdis;
> +	u32 dir;
> +	u32 dirs;
> +	u32 dirc;
> +	u32 slpm;
> +	u32 afsla;
> +	u32 afslb;
> +	u32 lowemi;
> +};
> +
> +struct nmk_pinctrl_priv {
> +	struct nmk_gpio_regs *bank[NMK_GPIO_BANKS];
> +};
> +
> +enum nmk_alt {
> +	NMK_ALT_GPIO,
> +	NMK_ALT_A,
> +	NMK_ALT_B,
> +	NMK_ALT_C,
> +};
> +
> +static int nmk_pinctrl_parse_pin(const char *name, unsigned int *pin)
> +{
> +	char *end;
> +
> +	if (strncmp(name, "GPIO", 4))
> +		return -EINVAL;
> +
> +	*pin = dectoul(name + 4, &end);
> +	if (end == name + 4 || *end != '_' ||
> +	    *pin >= NMK_GPIO_BANKS * NMK_GPIO_PER_BANK)
> +		return -EINVAL;
> +
> +	return 0;
> +}
> +
> +static struct nmk_gpio_regs *
> +nmk_pinctrl_bank(struct udevice *dev, unsigned int pin)
> +{
> +	struct nmk_pinctrl_priv *priv = dev_get_priv(dev);
> +
> +	return priv->bank[pin / NMK_GPIO_PER_BANK];
> +}
> +
> +static void nmk_pinctrl_set_mux(struct udevice *dev, unsigned int pin,
> +				unsigned int alt)
> +{
> +	struct nmk_gpio_regs *regs = nmk_pinctrl_bank(dev, pin);
> +	u32 mask = BIT(pin % NMK_GPIO_PER_BANK);
> +	u32 val;
> +
> +	val = readl(&regs->afsla);
> +	if (alt & NMK_ALT_A)
> +		val |= mask;
> +	else
> +		val &= ~mask;
> +	writel(val, &regs->afsla);
> +
> +	val = readl(&regs->afslb);
> +	if (alt & NMK_ALT_B)
> +		val |= mask;
> +	else
> +		val &= ~mask;
> +	writel(val, &regs->afslb);
> +}
> +
> +static int nmk_pinctrl_set_config(struct udevice *dev, ofnode node,
> +				  unsigned int pin)
> +{
> +	struct nmk_gpio_regs *regs = nmk_pinctrl_bank(dev, pin);
> +	u32 mask = BIT(pin % NMK_GPIO_PER_BANK);
> +	u32 val;
> +
> +	if (!ofnode_read_u32(node, "ste,input", &val)) {
> +		writel(mask, &regs->dirc);
> +		if (val == INPUT_NOPULL) {
> +			setbits_le32(&regs->pdis, mask);
> +		} else {
> +			clrbits_le32(&regs->pdis, mask);
> +			if (val == INPUT_PULLUP)
> +				writel(mask, &regs->dats);
> +			else if (val == INPUT_PULLDOWN)
> +				writel(mask, &regs->datc);
> +			else
> +				return -EINVAL;
> +		}
> +	}
> +
> +	if (!ofnode_read_u32(node, "ste,output", &val)) {
> +		if (val == OUTPUT_HIGH)
> +			writel(mask, &regs->dats);
> +		else if (val == OUTPUT_LOW)
> +			writel(mask, &regs->datc);
> +		else
> +			return -EINVAL;
> +		writel(mask, &regs->dirs);
> +	}
> +
> +	if (!ofnode_read_u32(node, "ste,lowemi", &val)) {
> +		if (val)
> +			setbits_le32(&regs->lowemi, mask);
> +		else
> +			clrbits_le32(&regs->lowemi, mask);
> +	}
> +
> +	return 0;
> +}
> +
> +static int nmk_pinctrl_get_alt(ofnode node, unsigned int *alt)
> +{
> +	const char *group;
> +
> +	if (ofnode_read_string_index(node, "groups", 0, &group))
> +		return -EINVAL;
> +
> +	if (strstr(group, "_a_"))
> +		*alt = NMK_ALT_A;
> +	else if (strstr(group, "_b_"))
> +		*alt = NMK_ALT_B;
> +	else if (strstr(group, "_c_"))
> +		*alt = NMK_ALT_C;
> +	else
> +		return -EINVAL;
> +
> +	return 0;
> +}
> +
> +static int nmk_pinctrl_set_state(struct udevice *dev, struct udevice *config)
> +{
> +	unsigned int alt = NMK_ALT_GPIO;
> +	ofnode node;
> +	int count;
> +	int ret;
> +	int i;
> +
> +	dev_for_each_subnode(node, config) {
> +		if (ofnode_read_string(node, "function")) {
> +			ret = nmk_pinctrl_get_alt(node, &alt);
> +			if (ret)
> +				return ret;
> +		}
> +	}
> +
> +	dev_for_each_subnode(node, config) {
> +		ofnode cfg;
> +
> +		count = ofnode_read_string_count(node, "pins");
> +		if (count < 0)
> +			continue;
> +
> +		cfg = ofnode_parse_phandle(node, "ste,config", 0);
> +		if (!ofnode_valid(cfg))
> +			cfg = node;
> +
> +		for (i = 0; i < count; i++) {
> +			const char *name;
> +			unsigned int pin;
> +
> +			ret = ofnode_read_string_index(node, "pins", i, &name);
> +			if (ret)
> +				return ret;
> +			ret = nmk_pinctrl_parse_pin(name, &pin);
> +			if (ret)
> +				return ret;
> +			ret = nmk_pinctrl_set_config(dev, cfg, pin);
> +			if (ret)
> +				return ret;
> +			nmk_pinctrl_set_mux(dev, pin, alt);
> +		}
> +	}
> +
> +	return 0;
> +}
> +
> +static int nmk_pinctrl_probe(struct udevice *dev)
> +{
> +	struct nmk_pinctrl_priv *priv = dev_get_priv(dev);
> +	struct ofnode_phandle_args args;
> +	fdt_addr_t addr;
> +	int ret;
> +	int i;
> +
> +	for (i = 0; i < NMK_GPIO_BANKS; i++) {
> +		ret = dev_read_phandle_with_args(dev, "nomadik-gpio-chips",
> +						 NULL, 0, i, &args);
> +		if (ret)
> +			return ret;
> +
> +		addr = ofnode_get_addr(args.node);
> +		if (addr == FDT_ADDR_T_NONE)
> +			return -EINVAL;
> +		priv->bank[i] = (struct nmk_gpio_regs *)addr;
> +	}
> +
> +	return 0;
> +}
> +
> +static const struct pinctrl_ops nmk_pinctrl_ops = {
> +	.set_state = nmk_pinctrl_set_state,
> +};
> +
> +static const struct udevice_id nmk_pinctrl_ids[] = {
> +	{ .compatible = "stericsson,db8500-pinctrl" },
> +	{ }
> +};
> +
> +U_BOOT_DRIVER(pinctrl_nomadik) = {
> +	.name = "pinctrl_nomadik",
> +	.id = UCLASS_PINCTRL,
> +	.of_match = nmk_pinctrl_ids,
> +	.probe = nmk_pinctrl_probe,
> +	.priv_auto = sizeof(struct nmk_pinctrl_priv),
> +	.ops = &nmk_pinctrl_ops,
> +};
> 
> -- 
> 2.55.0
>