Allow the mux to have the same address as a child device. This is useful
when the mux can only use an i2c-address that is used by a child device
because no other addresses are free to use. eg. the mux can only use
address 0x18 which is used by amc6821 connected to the mux.
Signed-off-by: Farouk Bouabid <farouk.bouabid@xxxxxxxxxxxxxxxxxxxxx>
---
drivers/i2c/i2c-mux.c | 10 +++++++++-
include/linux/i2c-mux.h | 1 +
2 files changed, 10 insertions(+), 1 deletion(-)
diff --git a/drivers/i2c/i2c-mux.c b/drivers/i2c/i2c-mux.c
index 57ff09f18c37..f5357dff8cc5 100644
--- a/drivers/i2c/i2c-mux.c
+++ b/drivers/i2c/i2c-mux.c
@@ -331,7 +331,6 @@ int i2c_mux_add_adapter(struct i2c_mux_core *muxc,
priv->adap.owner = THIS_MODULE;
priv->adap.algo = &priv->algo;
priv->adap.algo_data = priv;
- priv->adap.dev.parent = &parent->dev;
priv->adap.retries = parent->retries;
priv->adap.timeout = parent->timeout;
priv->adap.quirks = parent->quirks;
@@ -348,6 +347,15 @@ int i2c_mux_add_adapter(struct i2c_mux_core *muxc,
else
priv->adap.class = class;
+ /*
+ * When creating the adapter, the node devices are checked for i2c address
+ * match with other devices on the parent adapter, among which is the mux itself.
+ * If a match is found the node device is not probed successfully.
+ * Allow the mux to have the same address as a child device by skipping this check.
+ */
+ if (!(muxc->share_addr_with_children))
+ priv->adap.dev.parent = &parent->dev;
+
/*
* Try to populate the mux adapter's of_node, expands to
* nothing if !CONFIG_OF.
diff --git a/include/linux/i2c-mux.h b/include/linux/i2c-mux.h
index 98ef73b7c8fd..17ac68bf1703 100644
--- a/include/linux/i2c-mux.h
+++ b/include/linux/i2c-mux.h
@@ -21,6 +21,7 @@ struct i2c_mux_core {
unsigned int mux_locked:1;
unsigned int arbitrator:1;
unsigned int gate:1;
+ unsigned int share_addr_with_children:1;
void *priv;
--
2.34.1
