From 0a45c1a002705c8622738fbd2a2913acf886ea27 Mon Sep 17 00:00:00 2001 From: Ahmad Fatoum Date: Wed, 7 May 2025 15:07:25 +0200 Subject: [PATCH] gpio: mxc: configure dynamic GPIO base for CONFIG_GPIO_SYSFS=n i.MX GPIO numbering has been deterministic since commit 7e6086d9e54a ("gpio/mxc: specify gpio base for device tree probe"), a year after device tree support was first added back in 2011. Reverting to dynamically allocated GPIO base now would break most systems making use of the sysfs API. These systems will be eventually broken by the removal of the sysfs API, but that would result in GPIO scripts not working instead of essentially toggling at random according to probe order, which would happen if we unconditionally set base to -1. Yet, the warning is annoying and has resulted in many rejected attempts to remove it over the years[1][2][3]. As the i.MX GPIO driver is device tree only, GPIO_SYSFS is the only consumer of the deterministic GPIO numbering. Let's therefore restrict the static base and the warning that comes with it to configurations with CONFIG_GPIO_SYSFS enabled. [1]: https://lore.kernel.org/all/20230226205319.1013332-1-dario.binacchi@amarulasolutions.com/ [2]: https://lore.kernel.org/all/20230506085928.933737-2-haibo.chen@nxp.com/ [3]: https://lore.kernel.org/all/20241121145515.3087855-1-catalin.popescu@leica-geosystems.com/ Signed-off-by: Ahmad Fatoum Reviewed-by: Linus Walleij Link: https://lore.kernel.org/r/20250507-b4-imx-gpio-base-warning-v2-1-d43d09e2c6bf@pengutronix.de Signed-off-by: Bartosz Golaszewski --- drivers/gpio/gpio-mxc.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/drivers/gpio/gpio-mxc.c b/drivers/gpio/gpio-mxc.c index 619b6fb9d833a..38504c9486b05 100644 --- a/drivers/gpio/gpio-mxc.c +++ b/drivers/gpio/gpio-mxc.c @@ -490,7 +490,14 @@ static int mxc_gpio_probe(struct platform_device *pdev) port->gc.request = mxc_gpio_request; port->gc.free = mxc_gpio_free; port->gc.to_irq = mxc_gpio_to_irq; - port->gc.base = of_alias_get_id(np, "gpio") * 32; + /* + * Driver is DT-only, so a fixed base needs only be maintained for legacy + * userspace with sysfs interface. + */ + if (IS_ENABLED(CONFIG_GPIO_SYSFS)) + port->gc.base = of_alias_get_id(np, "gpio") * 32; + else /* silence boot time warning */ + port->gc.base = -1; err = devm_gpiochip_add_data(&pdev->dev, &port->gc, port); if (err) -- 2.47.3