[PATCH RFC 3/7] i3c: master: Add helper to query bus wakeup requirements

[Adrian Hunter]

Add i3c_master_any_wakeup_enabled(), which iterates over the devices on
an I3C bus and reports whether any of them are enabled for system
wakeup.

Controller drivers can use this helper to determine whether wakeup
support must remain available while the system is suspended.

Signed-off-by: Adrian Hunter <adrian.hunter at intel.com>
---
 drivers/i3c/master.c       | 27 +++++++++++++++++++++++++++
 include/linux/i3c/master.h |  1 +
 2 files changed, 28 insertions(+)

diff --git a/drivers/i3c/master.c b/drivers/i3c/master.c
index a36f9b617cbf..979457e635bd 100644
--- a/drivers/i3c/master.c
+++ b/drivers/i3c/master.c
@@ -1957,6 +1957,33 @@ static void i3c_master_reg_work_fn(struct work_struct *work)
 	i3c_bus_normaluse_unlock(&master->bus);
 }
 
+/**
+ * i3c_master_any_wakeup_enabled() - check if any device can wake the system
+ * @master: I3C master controller
+ *
+ * Iterate over devices on the bus and return true if any device has
+ * system wakeup enabled.
+ *
+ * Return: true if any device may wake the system, false otherwise.
+ */
+bool i3c_master_any_wakeup_enabled(struct i3c_master_controller *master)
+{
+	struct i3c_dev_desc *desc;
+	bool wakeup = false;
+
+	i3c_bus_normaluse_lock(&master->bus);
+	i3c_bus_for_each_i3cdev(&master->bus, desc) {
+		if (desc->dev && device_may_wakeup(&desc->dev->dev)) {
+			wakeup = true;
+			break;
+		}
+	}
+	i3c_bus_normaluse_unlock(&master->bus);
+
+	return wakeup;
+}
+EXPORT_SYMBOL_GPL(i3c_master_any_wakeup_enabled);
+
 /**
  * i3c_master_dma_map_single() - Map buffer for single DMA transfer
  * @dev: device object of a device doing DMA
diff --git a/include/linux/i3c/master.h b/include/linux/i3c/master.h
index af3c35a8e7b6..b9f2d84ac276 100644
--- a/include/linux/i3c/master.h
+++ b/include/linux/i3c/master.h
@@ -746,6 +746,7 @@ void i3c_generic_ibi_recycle_slot(struct i3c_generic_ibi_pool *pool,
 				  struct i3c_ibi_slot *slot);
 
 void i3c_master_queue_ibi(struct i3c_dev_desc *dev, struct i3c_ibi_slot *slot);
+bool i3c_master_any_wakeup_enabled(struct i3c_master_controller *master);
 
 struct i3c_ibi_slot *i3c_master_get_free_ibi_slot(struct i3c_dev_desc *dev);
 
-- 
2.53.0