pinctrl: Show selected function and group in pinmux-pins debugfs

Until recently, the pinctrl pinmux-pins debugfs file displayed the
selected function for each owned pin. This feature was removed during
restructing in support of recent API rework. This change restoreds this
feature, and also displays the group that the function was selected on,
in case a pin is a member of multiple groups.

Based on work by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/pinctrl/core.h

@@ -126,6 +126,7 @@ struct pinctrl_setting {
  * @owner: The name of the entity owning the pin. Typically, this is the name
  *	of the device that called pinctrl_get(). Alternatively, it may be the
  *	name of the GPIO passed to pinctrl_request_gpio().
+ * @mux_setting: The most recent selected mux setting for this pin, if any.
  */
 struct pin_desc {
 	struct pinctrl_dev *pctldev;
@@ -135,6 +136,7 @@ struct pin_desc {
 #ifdef CONFIG_PINMUX
 	unsigned usecount;
 	const char *owner;
+	const struct pinctrl_setting_mux *mux_setting;
 #endif
 };
 

drivers/pinctrl/pinmux.c

@@ -187,6 +187,7 @@ static const char *pin_free(struct pinctrl_dev *pctldev, int pin,
 
 	owner = desc->owner;
 	desc->owner = NULL;
+	desc->mux_setting = NULL;
 	module_put(pctldev->owner);
 
 	return owner;
@@ -378,7 +379,34 @@ void pinmux_free_setting(struct pinctrl_setting const *setting)
 int pinmux_enable_setting(struct pinctrl_setting const *setting)
 {
 	struct pinctrl_dev *pctldev = setting->pctldev;
+	const struct pinctrl_ops *pctlops = pctldev->desc->pctlops;
 	const struct pinmux_ops *ops = pctldev->desc->pmxops;
+	int ret;
+	const unsigned *pins;
+	unsigned num_pins;
+	int i;
+	struct pin_desc *desc;
+
+	ret = pctlops->get_group_pins(pctldev, setting->data.mux.group,
+				      &pins, &num_pins);
+	if (ret) {
+		/* errors only affect debug data, so just warn */
+		dev_warn(pctldev->dev,
+			 "could not get pins for group selector %d\n",
+			 setting->data.mux.group);
+		num_pins = 0;
+	}
+
+	for (i = 0; i < num_pins; i++) {
+		desc = pin_desc_get(pctldev, pins[i]);
+		if (desc == NULL) {
+			dev_warn(pctldev->dev,
+				 "could not get pin desc for pin %d\n",
+				 pins[i]);
+			continue;
+		}
+		desc->mux_setting = &(setting->data.mux);
+	}
 
 	return ops->enable(pctldev, setting->data.mux.func,
 			   setting->data.mux.group);
@@ -387,7 +415,34 @@ int pinmux_enable_setting(struct pinctrl_setting const *setting)
 void pinmux_disable_setting(struct pinctrl_setting const *setting)
 {
 	struct pinctrl_dev *pctldev = setting->pctldev;
+	const struct pinctrl_ops *pctlops = pctldev->desc->pctlops;
 	const struct pinmux_ops *ops = pctldev->desc->pmxops;
+	int ret;
+	const unsigned *pins;
+	unsigned num_pins;
+	int i;
+	struct pin_desc *desc;
+
+	ret = pctlops->get_group_pins(pctldev, setting->data.mux.group,
+				      &pins, &num_pins);
+	if (ret) {
+		/* errors only affect debug data, so just warn */
+		dev_warn(pctldev->dev,
+			 "could not get pins for group selector %d\n",
+			 setting->data.mux.group);
+		num_pins = 0;
+	}
+
+	for (i = 0; i < num_pins; i++) {
+		desc = pin_desc_get(pctldev, pins[i]);
+		if (desc == NULL) {
+			dev_warn(pctldev->dev,
+				 "could not get pin desc for pin %d\n",
+				 pins[i]);
+			continue;
+		}
+		desc->mux_setting = NULL;
+	}
 
 	ops->disable(pctldev, setting->data.mux.func, setting->data.mux.group);
 }
@@ -433,6 +488,8 @@ static int pinmux_functions_show(struct seq_file *s, void *what)
 static int pinmux_pins_show(struct seq_file *s, void *what)
 {
 	struct pinctrl_dev *pctldev = s->private;
+	const struct pinctrl_ops *pctlops = pctldev->desc->pctlops;
+	const struct pinmux_ops *pmxops = pctldev->desc->pmxops;
 	unsigned i, pin;
 
 	seq_puts(s, "Pinmux settings per pin\n");
@@ -455,10 +512,19 @@ static int pinmux_pins_show(struct seq_file *s, void *what)
 		    !strcmp(desc->owner, pinctrl_dev_get_name(pctldev)))
 			is_hog = true;
 
-		seq_printf(s, "pin %d (%s): %s%s\n", pin,
+		seq_printf(s, "pin %d (%s): %s%s", pin,
 			   desc->name ? desc->name : "unnamed",
 			   desc->owner ? desc->owner : "UNCLAIMED",
 			   is_hog ? " (HOG)" : "");
+
+		if (desc->mux_setting)
+			seq_printf(s, " function %s group %s\n",
+				   pmxops->get_function_name(pctldev,
+					desc->mux_setting->func),
+				   pctlops->get_group_name(pctldev,
+					desc->mux_setting->group));
+		else
+			seq_printf(s, "\n");
 	}
 
 	mutex_unlock(&pinctrl_mutex);