pinctrl: Add the concept of peripheral IDs

My original pinctrl patch operating using a peripheral ID enum. This was
shared between pinmux and clock and provides an easy way to specify a device
that needs to be controlled, even it is does not (yet) have a driver within
driver model.

Masahiro's new simple pinctrl gets around this by providing a
set_state_simple() pinctrl method. By passing a device to that call the
peripheral ID becomes unnecessary. If the driver needs it, it can calculate
it itself and use it internally.

However this does not solve the problem for peripheral clocks. The 'pure'
solution would be to pass a driver to the clock uclass also. But this
requires that all devices should have a driver, and a struct udevide. Also
a key optimisation of the clock uclass is allowing a peripheral clock to
be set even when there is no device for that clock.

There may be a better way to achive the same goal, but for now it seems
expedient to add in peripheral ID to the pinctrl uclass. Two methods are
added - one to get the peripheral ID and one to select it. The existing
set_state_simple() is effectively the union of these.

Signed-off-by: Simon Glass <sjg@chromium.org>

drivers/pinctrl/pinctrl-uclass.c

@@ -11,6 +11,7 @@
 #include <dm/device.h>
 #include <dm/lists.h>
 #include <dm/pinctrl.h>
+#include <dm/root.h>
 #include <dm/uclass.h>
 
 DECLARE_GLOBAL_DATA_PTR;
@@ -159,7 +160,8 @@ static int pinctrl_select_state_full(struct udevice *dev, const char *statename)
 
 static int pinconfig_post_bind(struct udevice *dev)
 {
-	return 0;
+	/* Scan the bus for devices */
+	return dm_scan_fdt_node(dev, gd->fdt_blob, dev->of_offset, false);
 }
 #endif
 
@@ -205,6 +207,31 @@ int pinctrl_select_state(struct udevice *dev, const char *statename)
 	return 0;
 }
 
+int pinctrl_request(struct udevice *dev, int func, int flags)
+{
+	struct pinctrl_ops *ops = pinctrl_get_ops(dev);
+
+	if (!ops->request)
+		return -ENOSYS;
+
+	return ops->request(dev, func, flags);
+}
+
+int pinctrl_request_noflags(struct udevice *dev, int func)
+{
+	return pinctrl_request(dev, func, 0);
+}
+
+int pinctrl_get_periph_id(struct udevice *dev, struct udevice *periph)
+{
+	struct pinctrl_ops *ops = pinctrl_get_ops(dev);
+
+	if (!ops->get_periph_id)
+		return -ENOSYS;
+
+	return ops->get_periph_id(dev, periph);
+}
+
 /**
  * pinconfig_post-bind() - post binding for PINCTRL uclass
  * Recursively bind child nodes as pinconfig devices in case of full pinctrl.
@@ -222,15 +249,10 @@ static int pinctrl_post_bind(struct udevice *dev)
 	}
 
 	/*
-	 * If set_state callback is set, we assume this pinctrl driver is the
-	 * full implementation.  In this case, its child nodes should be bound
-	 * so that peripheral devices can easily search in parent devices
-	 * during later DT-parsing.
+	 * The pinctrl driver child nodes should be bound so that peripheral
+	 * devices can easily search in parent devices during later DT-parsing.
 	 */
-	if (ops->set_state)
-		return pinconfig_post_bind(dev);
-
-	return 0;
+	return pinconfig_post_bind(dev);
 }
 
 UCLASS_DRIVER(pinctrl) = {

include/dm/pinctrl.h

@@ -87,7 +87,33 @@ struct pinctrl_ops {
 	int (*pinconf_group_set)(struct udevice *dev, unsigned group_selector,
 				 unsigned param, unsigned argument);
 	int (*set_state)(struct udevice *dev, struct udevice *config);
+
+	/* for pinctrl-simple */
 	int (*set_state_simple)(struct udevice *dev, struct udevice *periph);
+	/**
+	 * request() - Request a particular pinctrl function
+	 *
+	 * This activates the selected function.
+	 *
+	 * @dev:	Device to adjust (UCLASS_PINCTRL)
+	 * @func:	Function number (driver-specific)
+	 * @return 0 if OK, -ve on error
+	 */
+	int (*request)(struct udevice *dev, int func, int flags);
+
+	/**
+	* get_periph_id() - get the peripheral ID for a device
+	*
+	* This generally looks at the peripheral's device tree node to work
+	* out the peripheral ID. The return value is normally interpreted as
+	* enum periph_id. so long as this is defined by the platform (which it
+	* should be).
+	*
+	* @dev:		Pinctrl device to use for decoding
+	* @periph:	Device to check
+	* @return peripheral ID of @periph, or -ENOENT on error
+	*/
+	int (*get_periph_id)(struct udevice *dev, struct udevice *periph);
 };
 
 #define pinctrl_get_ops(dev)	((struct pinctrl_ops *)(dev)->driver->ops)
@@ -224,4 +250,38 @@ static inline int pinctrl_select_state(struct udevice *dev,
 }
 #endif
 
+/**
+ * pinctrl_request() - Request a particular pinctrl function
+ *
+ * @dev:	Device to check (UCLASS_PINCTRL)
+ * @func:	Function number (driver-specific)
+ * @flags:	Flags (driver-specific)
+ * @return 0 if OK, -ve on error
+ */
+int pinctrl_request(struct udevice *dev, int func, int flags);
+
+/**
+ * pinctrl_request_noflags() - Request a particular pinctrl function
+ *
+ * This is similar to pinctrl_request() but uses 0 for @flags.
+ *
+ * @dev:	Device to check (UCLASS_PINCTRL)
+ * @func:	Function number (driver-specific)
+ * @return 0 if OK, -ve on error
+ */
+int pinctrl_request_noflags(struct udevice *dev, int func);
+
+/**
+ * pinctrl_get_periph_id() - get the peripheral ID for a device
+ *
+ * This generally looks at the peripheral's device tree node to work out the
+ * peripheral ID. The return value is normally interpreted as enum periph_id.
+ * so long as this is defined by the platform (which it should be).
+ *
+ * @dev:	Pinctrl device to use for decoding
+ * @periph:	Device to check
+ * @return peripheral ID of @periph, or -ENOENT on error
+ */
+int pinctrl_get_periph_id(struct udevice *dev, struct udevice *periph);
+
 #endif /* __PINCTRL_H */