[PATCH 1/2] i2c: implement of_i2c_register_devices_by_node()

[Ahmad Fatoum <a.fatoum@pengutronix.de>]

i2c controllers probe the devices on their bus themselves, so in the
case the i2c controller was already probed, we currently have no way to
have it reread the device tree after fixing it up or applying an
overlay. Add a new helper that retriggers the device creation.

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
---
 drivers/i2c/i2c.c | 20 ++++++++++++++++++++
 include/i2c/i2c.h |  1 +
 2 files changed, 21 insertions(+)

diff --git a/drivers/i2c/i2c.c b/drivers/i2c/i2c.c
index b24fd88f5b39..e70e51618850 100644
--- a/drivers/i2c/i2c.c
+++ b/drivers/i2c/i2c.c
@@ -427,6 +427,12 @@ static void of_i2c_register_devices(struct i2c_adapter *adap)
 		const __be32 *addr;
 		int len;
 
+		if (n->dev) {
+			dev_dbg(&adap->dev, "of_i2c: skipping already registered %s\n",
+				dev_name(n->dev));
+			continue;
+		}
+
 		of_modalias_node(n, info.type, I2C_NAME_SIZE);
 
 		info.of_node = n;
@@ -452,6 +458,20 @@ static void of_i2c_register_devices(struct i2c_adapter *adap)
 	}
 }
 
+int of_i2c_register_devices_by_node(struct device_node *node)
+{
+	struct i2c_adapter *adap;
+
+	adap = of_find_i2c_adapter_by_node(node);
+	if (!adap)
+		return -ENODEV;
+	if (IS_ERR(adap))
+		return PTR_ERR(adap);
+
+	of_i2c_register_devices(adap);
+	return 0;
+}
+
 /**
  * i2c_new_dummy - return a new i2c device bound to a dummy driver
  * @adapter: the adapter managing the device
diff --git a/include/i2c/i2c.h b/include/i2c/i2c.h
index 7207b1180e1d..f5e2dc511ed1 100644
--- a/include/i2c/i2c.h
+++ b/include/i2c/i2c.h
@@ -295,6 +295,7 @@ static inline int i2c_register_board_info(int busnum,
 extern int i2c_add_numbered_adapter(struct i2c_adapter *adapter);
 struct i2c_adapter *i2c_get_adapter(int busnum);
 struct i2c_adapter *of_find_i2c_adapter_by_node(struct device_node *node);
+int of_i2c_register_devices_by_node(struct device_node *node);
 struct i2c_client *of_find_i2c_device_by_node(struct device_node *node);
 
 void i2c_parse_fw_timings(struct device_d *dev, struct i2c_timings *t, bool use_defaults);
-- 
2.30.2