drivers: pinctrl: add support for dynamic pin control

Add support for dynamic pin control, that is, allow to change device pin
configuration at runtime. Because no device de-initialization is
available yet, this API has limited usage options, e.g. modify pin
configuration at early boot stage (before device driver is initialized)

Signed-off-by: Gerard Marull-Paretas <gerard.marull@nordicsemi.no>

drivers/pinctrl/Kconfig

@@ -21,4 +21,12 @@ config PINCTRL_NON_STATIC
 	  a driver has to be accessed externally. This can happen, for example, when
 	  dynamic pin control is enabled or in testing environments.
 
+config PINCTRL_DYNAMIC
+	bool "Enable dynamic configuration of pins"
+	select PINCTRL_NON_STATIC
+	help
+	  When this option is enabled pin control configuration can be changed at
+	  runtime. This can be useful, for example, to change the pins assigned to a
+	  peripheral at early boot stages depending on a certain input.
+
 endif # PINCTRL

drivers/pinctrl/common.c

@@ -20,3 +20,36 @@ int pinctrl_lookup_state(const struct pinctrl_dev_config *config, uint8_t id,
 
 	return -ENOENT;
 }
+
+#ifdef CONFIG_PINCTRL_DYNAMIC
+int pinctrl_update_states(struct pinctrl_dev_config *config,
+			  const struct pinctrl_state *states,
+			  uint8_t state_cnt)
+{
+	uint8_t equal = 0U;
+
+	/* check we are inserting same number of states */
+	if (config->state_cnt != state_cnt) {
+		return -EINVAL;
+	}
+
+	/* check we have the same states */
+	for (uint8_t i = 0U; i < state_cnt; i++) {
+		for (uint8_t j = 0U; j < config->state_cnt; j++) {
+			if (states[i].id == config->states[j].id) {
+				equal++;
+				break;
+			}
+		}
+	}
+
+	if (equal != state_cnt) {
+		return -EINVAL;
+	}
+
+	/* replace current states */
+	config->states = states;
+
+	return 0;
+}
+#endif /* CONFIG_PINCTRL_DYNAMIC */

include/drivers/pinctrl.h

@@ -197,22 +197,29 @@ struct pinctrl_dev_config {
 #define Z_PINCTRL_DEV_CONFIG_STATIC static
 #endif
 
+#ifdef CONFIG_PINCTRL_DYNAMIC
+#define Z_PINCTRL_DEV_CONFIG_CONST
+#else
+#define Z_PINCTRL_DEV_CONFIG_CONST const
+#endif
+
 /** @endcond */
 
 #if defined(CONFIG_PINCTRL_NON_STATIC) || defined(__DOXYGEN__)
 /**
  * @brief Declare pin control configuration for a given node identifier.
  *
- * This macro should be used by tests to declare the pin control configuration
- * for a device. #PINCTRL_DT_DEV_CONFIG_GET can later be used to obtain a
- * reference to such configuration.
+ * This macro should be used by tests or applications using runtime pin control
+ * to declare the pin control configuration for a device.
+ * #PINCTRL_DT_DEV_CONFIG_GET can later be used to obtain a reference to such
+ * configuration.
  *
  * Only available if @kconfig{CONFIG_PINCTRL_NON_STATIC} is selected.
  *
  * @param node_id Node identifier.
  */
 #define PINCTRL_DT_DEV_CONFIG_DECLARE(node_id)				       \
-	extern const struct pinctrl_dev_config				       \
+	extern Z_PINCTRL_DEV_CONFIG_CONST struct pinctrl_dev_config	       \
 	Z_PINCTRL_DEV_CONFIG_NAME(node_id)
 #endif /* defined(CONFIG_PINCTRL_NON_STATIC) || defined(__DOXYGEN__) */
 
@@ -231,8 +238,9 @@ struct pinctrl_dev_config {
 	UTIL_LISTIFY(DT_NUM_PINCTRL_STATES(node_id),			       \
 		     Z_PINCTRL_STATE_PINS_DEFINE, node_id)		       \
 	Z_PINCTRL_STATES_DEFINE(node_id)				       \
-	const Z_PINCTRL_DEV_CONFIG_STATIC struct pinctrl_dev_config	       \
-	Z_PINCTRL_DEV_CONFIG_NAME(node_id) = Z_PINCTRL_DEV_CONFIG_INIT(node_id);
+	Z_PINCTRL_DEV_CONFIG_CONST Z_PINCTRL_DEV_CONFIG_STATIC		       \
+	struct pinctrl_dev_config Z_PINCTRL_DEV_CONFIG_NAME(node_id) =	       \
+	Z_PINCTRL_DEV_CONFIG_INIT(node_id);
 
 /**
  * @brief Define all pin control information for the given compatible index.
@@ -342,6 +350,101 @@ static inline int pinctrl_apply_state(const struct pinctrl_dev_config *config,
 	return pinctrl_apply_state_direct(config, state);
 }
 
+#if defined(CONFIG_PINCTRL_DYNAMIC) || defined(__DOXYGEN__)
+/**
+ * @defgroup pinctrl_interface_dynamic Dynamic Pin Control
+ * @{
+ */
+
+/**
+ * @brief Helper macro to define the pins of a pin control state from
+ * Devicetree.
+ *
+ * The name of the defined state pins variable is the same used by @p prop. This
+ * macro is expected to be used in conjunction with #PINCTRL_DT_STATE_INIT.
+ *
+ * @param node_id Node identifier containing @p prop.
+ * @param prop Property within @p node_id containing state configuration.
+ *
+ * @see #PINCTRL_DT_STATE_INIT
+ */
+#define PINCTRL_DT_STATE_PINS_DEFINE(node_id, prop)			       \
+	static const pinctrl_soc_pin_t prop ## _pins[] =		       \
+	Z_PINCTRL_STATE_PINS_INIT(node_id, prop);			       \
+
+/**
+ * @brief Utility macro to initialize a pin control state.
+ *
+ * This macro should be used in conjunction with #PINCTRL_DT_STATE_PINS_DEFINE
+ * when using dynamic pin control to define an alternative state configuration
+ * stored in Devicetree.
+ *
+ * Example:
+ *
+ * @code{.devicetree}
+ * // board.dts
+ *
+ * /{
+ *      zephyr,user {
+ *              // uart0_alt_default node contains alternative pin config
+ *              uart0_alt_default = <&uart0_alt_default>;
+ *      };
+ * };
+ * @endcode
+ *
+ * @code{.c}
+ * // application
+ *
+ * PINCTRL_DT_STATE_PINS_DEFINE(DT_PATH(zephyr_user), uart0_alt_default);
+ *
+ * static const struct pinctrl_state uart0_alt[] = {
+ *     PINCTRL_DT_STATE_INIT(uart0_alt_default, PINCTRL_STATE_DEFAULT)
+ * };
+ * @endcode
+ *
+ * @param prop Property name in Devicetree containing state configuration.
+ * @param state State represented by @p prop (see @ref PINCTRL_STATES).
+ *
+ * @see #PINCTRL_DT_STATE_PINS_DEFINE
+ */
+#define PINCTRL_DT_STATE_INIT(prop, state)				       \
+	{								       \
+		.id = state,						       \
+		.pins = prop ## _pins,					       \
+		.pin_cnt = ARRAY_SIZE(prop ## _pins)			       \
+	}
+
+/**
+ * @brief Update states with a new set.
+ *
+ * @note In order to guarantee device drivers correct operation the same states
+ * have to be provided. For example, if @c default and @c sleep are in the
+ * current list of states, it is expected that the new array of states also
+ * contains both.
+ *
+ * @param config Pin control configuration.
+ * @param states New states to be set.
+ * @param state_cnt Number of new states to be set.
+ *
+ * @retval -EINVAL If the new configuration does not contain the same states as
+ * the current active configuration.
+ * @retval -ENOSYS If the functionality is not available.
+ * @retval 0 On success.
+ */
+int pinctrl_update_states(struct pinctrl_dev_config *config,
+			  const struct pinctrl_state *states,
+			  uint8_t state_cnt);
+
+/** @} */
+#else
+static inline int pinctrl_update_states(
+	struct pinctrl_dev_config *config,
+	const struct pinctrl_state *states, uint8_t state_cnt)
+{
+	return -ENOSYS;
+}
+#endif /* defined(CONFIG_PINCTRL_DYNAMIC) || defined(__DOXYGEN__) */
+
 #ifdef __cplusplus
 }
 #endif