pinctrl: meson-gx: add support for getting pinmux status

In order to support the "pinmux status" command, use the common functions
to get the pins count and names, and add the GX specific function to get
the current function from registers.
Signed-off-by: NNeil Armstrong <narmstrong@baylibre.com>
Tested-by: NMaxime Jourdan <mjourdan@baylibre.com>

drivers/pinctrl/meson/pinctrl-meson-gx-pmx.c

@@ -72,6 +72,47 @@ static int meson_gx_pinmux_group_set(struct udevice *dev,
 	return 0;
 }
 
+static int meson_gx_pinmux_get(struct udevice *dev,
+				      unsigned int selector,
+				      char *buf, int size)
+{
+	struct meson_pinctrl *priv = dev_get_priv(dev);
+	struct meson_pmx_group *group;
+	struct meson_gx_pmx_data *pmx_data;
+	void __iomem *addr;
+	int i, j, pos = 0;
+	unsigned int pin;
+	u32 reg;
+
+	pin = selector + priv->data->pin_base;
+
+	for (i = 0; i < priv->data->num_groups; i++) {
+		group = &priv->data->groups[i];
+		pmx_data = (struct meson_gx_pmx_data *)group->data;
+		if (pmx_data->is_gpio)
+			continue;
+
+		for (j = 0; j < group->num_pins; j++) {
+			if (group->pins[j] == pin) {
+				/* We have found a group using the pin */
+				addr = priv->reg_mux + pmx_data->reg * 4;
+				reg = readl(addr) & BIT(pmx_data->bit);
+				if (reg) {
+					pos += snprintf(buf + pos, size - pos,
+							"%s ", group->name) - 1;
+					return 0;
+				}
+			}
+		}
+	}
+
+	/* Fallback, must be used as GPIO */
+	snprintf(buf, size, "%s or Unknown",
+		 priv->data->groups[selector].name);
+
+	return 0;
+}
+
 const struct pinconf_param meson_gx_pinconf_params[] = {
 	{ "bias-disable", PIN_CONFIG_BIAS_DISABLE, 0 },
 	{ "bias-pull-up", PIN_CONFIG_BIAS_PULL_UP, 1 },
@@ -89,6 +130,9 @@ const struct pinctrl_ops meson_gx_pinctrl_ops = {
 	.pinconf_num_params = ARRAY_SIZE(meson_gx_pinconf_params),
 	.pinconf_set = meson_pinconf_set,
 	.pinconf_group_set = meson_pinconf_group_set,
+	.get_pin_name = meson_pinctrl_get_pin_name,
+	.get_pins_count = meson_pinctrl_get_pins_count,
+	.get_pin_muxing	= meson_gx_pinmux_get,
 };
 
 static const struct dm_gpio_ops meson_gx_gpio_ops = {