pinctrl: st: stop abusing of_get_named_gpio()

Pin descriptions for this chip only look like standard GPIO device tree
descriptions, while in fact they contain additional data (in excess of
number of cells specified in description of gpio controllers). They also
refer to only pins/gpios belonging to the driver and not to arbitrary
gpio in the system.

Because we want to stop exporting OF-specific handlers from gpiolib-of,
let's parse the pin reference ourself instead of trying to call
of_get_named_gpio().

Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Tested-by: Patrice Chotard <patrice.chotard@foss.st.com>
Reviewed-by: Patrice Chotard <patrice.chotard@foss.st.com>
Link: https://lore.kernel.org/r/YzSsgoVoJn4+mSpv@google.com
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/pinctrl/pinctrl-st.c

@@ -12,7 +12,6 @@
 #include <linux/io.h>
 #include <linux/of.h>
 #include <linux/of_irq.h>
-#include <linux/of_gpio.h> /* of_get_named_gpio() */
 #include <linux/of_address.h>
 #include <linux/gpio/driver.h>
 #include <linux/regmap.h>
@@ -1162,6 +1161,31 @@ static void st_parse_syscfgs(struct st_pinctrl *info, int bank,
 	return;
 }
 
+static int st_pctl_dt_calculate_pin(struct st_pinctrl *info,
+				    phandle bank, unsigned int offset)
+{
+	struct device_node *np;
+	struct gpio_chip *chip;
+	int retval = -EINVAL;
+	int i;
+
+	np = of_find_node_by_phandle(bank);
+	if (!np)
+		return -EINVAL;
+
+	for (i = 0; i < info->nbanks; i++) {
+		chip = &info->banks[i].gpio_chip;
+		if (chip->of_node == np) {
+			if (offset < chip->ngpio)
+				retval = chip->base + offset;
+			break;
+		}
+	}
+
+	of_node_put(np);
+	return retval;
+}
+
 /*
  * Each pin is represented in of the below forms.
  * <bank offset mux direction rt_type rt_delay rt_clk>
@@ -1175,6 +1199,8 @@ static int st_pctl_dt_parse_groups(struct device_node *np,
 	struct device *dev = info->dev;
 	struct st_pinconf *conf;
 	struct device_node *pins;
+	phandle bank;
+	unsigned int offset;
 	int i = 0, npins = 0, nr_props, ret = 0;
 
 	pins = of_get_child_by_name(np, "st,pins");
@@ -1214,9 +1240,9 @@ static int st_pctl_dt_parse_groups(struct device_node *np,
 		conf = &grp->pin_conf[i];
 
 		/* bank & offset */
-		be32_to_cpup(list++);
-		be32_to_cpup(list++);
-		conf->pin = of_get_named_gpio(pins, pp->name, 0);
+		bank = be32_to_cpup(list++);
+		offset = be32_to_cpup(list++);
+		conf->pin = st_pctl_dt_calculate_pin(info, bank, offset);
 		conf->name = pp->name;
 		grp->pins[i] = conf->pin;
 		/* mux */