Re: [PATCH] gpio: tegra186: Support multi-socket devices

[Bartosz Golaszewski]

On Mon, 16 Feb 2026 05:58:42 +0100, Prathamesh Shete <pshete@xxxxxxxxxx> said:
> On Tegra platforms, multiple SoC instances may be present with each
> defining the same GPIO name. For such devices, this results in
> duplicate GPIO names.
>
> When the device has a valid NUMA node, prepend the NUMA node ID
> to the GPIO name prefix. The node ID identifies each socket,
> ensuring GPIO line names remain distinct across multiple sockets.
>
> Signed-off-by: Prathamesh Shete <pshete@xxxxxxxxxx>
> ---
>  drivers/gpio/gpio-tegra186.c | 26 +++++++++++++++++---------
>  1 file changed, 17 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/gpio/gpio-tegra186.c b/drivers/gpio/gpio-tegra186.c
> index 9c874f07be75..daf5aaffa28a 100644
> --- a/drivers/gpio/gpio-tegra186.c
> +++ b/drivers/gpio/gpio-tegra186.c
> @@ -857,7 +857,8 @@ static int tegra186_gpio_probe(struct platform_device *pdev)
>  	struct device_node *np;
>  	struct resource *res;
>  	char **names;
> -	int err;
> +	char *instance = "";
> +	int node, err;
>
>  	gpio = devm_kzalloc(&pdev->dev, sizeof(*gpio), GFP_KERNEL);
>  	if (!gpio)
> @@ -937,17 +938,21 @@ static int tegra186_gpio_probe(struct platform_device *pdev)
>  	if (!names)
>  		return -ENOMEM;
>
> +	node = dev_to_node(&pdev->dev);
> +	if (node >= 0) {
> +		instance = devm_kasprintf(gpio->gpio.parent, GFP_KERNEL, "%d-", node);

I've never noticed it before (and it's not introduced by this patch) but I
really dislike the child device registering devres nodes with its parent...

> +		if (!instance)
> +			return -ENOMEM;
> +	}
> +
>  	for (i = 0, offset = 0; i < gpio->soc->num_ports; i++) {
>  		const struct tegra_gpio_port *port = &gpio->soc->ports[i];
>  		char *name;
>
>  		for (j = 0; j < port->pins; j++) {
> -			if (gpio->soc->prefix)
> -				name = devm_kasprintf(gpio->gpio.parent, GFP_KERNEL, "%s-P%s.%02x",
> -						      gpio->soc->prefix, port->name, j);
> -			else
> -				name = devm_kasprintf(gpio->gpio.parent, GFP_KERNEL, "P%s.%02x",
> -						      port->name, j);
> +			name = devm_kasprintf(gpio->gpio.parent, GFP_KERNEL, "%s%sP%s.%02x",
> +					      instance ?: "", gpio->soc->prefix ?: "",

instance can't be NULL here, can it? Either print it unconditionally or
initialize it to NULL.

> +					      port->name, j);
>  			if (!name)
>  				return -ENOMEM;
>
> @@ -1373,6 +1378,9 @@ static const struct tegra_gpio_soc tegra256_main_soc = {
>  	.has_vm_support = true,
>  };
>
> +/* Macro to define GPIO name prefix with separator */
> +#define TEGRA_GPIO_PREFIX(_x)	_x "-"
> +

This doesn't look like it belongs to this patch, why are you doing it?

Bart

>  #define TEGRA410_COMPUTE_GPIO_PORT(_name, _bank, _port, _pins)	\
>  	TEGRA_GPIO_PORT(TEGRA410_COMPUTE, _name, _bank, _port, _pins)
>
> @@ -1388,7 +1396,7 @@ static const struct tegra_gpio_soc tegra410_compute_soc = {
>  	.num_ports = ARRAY_SIZE(tegra410_compute_ports),
>  	.ports = tegra410_compute_ports,
>  	.name = "tegra410-gpio-compute",
> -	.prefix = "COMPUTE",
> +	.prefix = TEGRA_GPIO_PREFIX("COMPUTE"),
>  	.num_irqs_per_bank = 8,
>  	.instance = 0,
>  };
> @@ -1418,7 +1426,7 @@ static const struct tegra_gpio_soc tegra410_system_soc = {
>  	.num_ports = ARRAY_SIZE(tegra410_system_ports),
>  	.ports = tegra410_system_ports,
>  	.name = "tegra410-gpio-system",
> -	.prefix = "SYSTEM",
> +	.prefix = TEGRA_GPIO_PREFIX("SYSTEM"),
>  	.num_irqs_per_bank = 8,
>  	.instance = 0,
>  };
> --
> 2.43.0
>
>