@@ -45,6 +45,11 @@ struct mxc_gpio_hwdata {
unsigned high_level;
unsigned rise_edge;
unsigned fall_edge;
+ /*
+ * Static allocation of GPIO base is deprecated.
+ * Set this to false for future SoCs.
+ */
+ bool gpio_base_static_alloc;
};
struct mxc_gpio_reg_saved {
@@ -88,6 +93,7 @@ static struct mxc_gpio_hwdata imx1_imx21_gpio_hwdata = {
.high_level = 0x02,
.rise_edge = 0x00,
.fall_edge = 0x01,
+ .gpio_base_static_alloc = true,
};
static struct mxc_gpio_hwdata imx31_gpio_hwdata = {
@@ -103,6 +109,7 @@ static struct mxc_gpio_hwdata imx31_gpio_hwdata = {
.high_level = 0x01,
.rise_edge = 0x02,
.fall_edge = 0x03,
+ .gpio_base_static_alloc = true,
};
static struct mxc_gpio_hwdata imx35_gpio_hwdata = {
@@ -118,6 +125,7 @@ static struct mxc_gpio_hwdata imx35_gpio_hwdata = {
.high_level = 0x01,
.rise_edge = 0x02,
.fall_edge = 0x03,
+ .gpio_base_static_alloc = true,
};
#define GPIO_DR (port->hwdata->dr_reg)
@@ -490,7 +498,19 @@ 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;
+ port->gc.base = -1;
+
+ if (port->hwdata->gpio_base_static_alloc) {
+ /*
+ * GPIO indices have been fixed for the i.MX GPIO controllers
+ * for many years and changing that now will induce a lot of
+ * breakage at runtime. Setting this member buys users some time
+ * until they are forced to migrate when sysfs GPIO support is
+ * removed completely.
+ */
+ port->gc.legacy_static_base = true;
+ port->gc.base = of_alias_get_id(np, "gpio") * 32;
+ }
err = devm_gpiochip_add_data(&pdev->dev, &port->gc, port);
if (err)
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 change the base to -1. Yet, the warning is annoying and has resulted in many attempts to remove it over the years[1][2][3]. Fix this by silencing the warning via the gpio_base_static_alloc opt-out instead. [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 <a.fatoum@pengutronix.de> --- This triggers the newly added checkpatch.pl warning, but this is intended. --- drivers/gpio/gpio-mxc.c | 22 +++++++++++++++++++++- 1 file changed, 21 insertions(+), 1 deletion(-)