From: Luca Ceresoli <l...@lucaceresoli.net>

i2c-mux instantiates one i2c_algorithm for each downstream adapter.
However these algorithms are all identical, depending only on the
parent adapter.

Avoid duplication by hoisting the i2c_algorithm from the adapters to
the i2c_mux_core object, and reuse it in all the adapters.

Signed-off-by: Luca Ceresoli <l...@lucaceresoli.net>

---

Changes v1 -> v2:
 - include i2c.h (fixes build failure on i2c-mux-ltc4306)
---
 drivers/i2c/i2c-mux.c   | 37 ++++++++++++++++++-------------------
 include/linux/i2c-mux.h |  2 ++
 2 files changed, 20 insertions(+), 19 deletions(-)

diff --git a/drivers/i2c/i2c-mux.c b/drivers/i2c/i2c-mux.c
index f330690b4125..2b0cc2ad0a17 100644
--- a/drivers/i2c/i2c-mux.c
+++ b/drivers/i2c/i2c-mux.c
@@ -30,7 +30,6 @@
 /* multiplexer per channel data */
 struct i2c_mux_priv {
        struct i2c_adapter adap;
-       struct i2c_algorithm algo;
        struct i2c_mux_core *muxc;
        u32 chan_id;
 };
@@ -263,6 +262,23 @@ struct i2c_mux_core *i2c_mux_alloc(struct i2c_adapter 
*parent,
        muxc->deselect = deselect;
        muxc->max_adapters = max_adapters;
 
+       /* Need to do algo dynamically because we don't know ahead
+        * of time what sort of physical adapter we'll be dealing with.
+        */
+       if (parent->algo->master_xfer) {
+               if (muxc->mux_locked)
+                       muxc->algo.master_xfer = i2c_mux_master_xfer;
+               else
+                       muxc->algo.master_xfer = __i2c_mux_master_xfer;
+       }
+       if (parent->algo->smbus_xfer) {
+               if (muxc->mux_locked)
+                       muxc->algo.smbus_xfer = i2c_mux_smbus_xfer;
+               else
+                       muxc->algo.smbus_xfer = __i2c_mux_smbus_xfer;
+       }
+       muxc->algo.functionality = i2c_mux_functionality;
+
        return muxc;
 }
 EXPORT_SYMBOL_GPL(i2c_mux_alloc);
@@ -301,28 +317,11 @@ int i2c_mux_add_adapter(struct i2c_mux_core *muxc,
        priv->muxc = muxc;
        priv->chan_id = chan_id;
 
-       /* Need to do algo dynamically because we don't know ahead
-        * of time what sort of physical adapter we'll be dealing with.
-        */
-       if (parent->algo->master_xfer) {
-               if (muxc->mux_locked)
-                       priv->algo.master_xfer = i2c_mux_master_xfer;
-               else
-                       priv->algo.master_xfer = __i2c_mux_master_xfer;
-       }
-       if (parent->algo->smbus_xfer) {
-               if (muxc->mux_locked)
-                       priv->algo.smbus_xfer = i2c_mux_smbus_xfer;
-               else
-                       priv->algo.smbus_xfer = __i2c_mux_smbus_xfer;
-       }
-       priv->algo.functionality = i2c_mux_functionality;
-
        /* Now fill out new adapter structure */
        snprintf(priv->adap.name, sizeof(priv->adap.name),
                 "i2c-%d-mux (chan_id %d)", i2c_adapter_id(parent), chan_id);
        priv->adap.owner = THIS_MODULE;
-       priv->adap.algo = &priv->algo;
+       priv->adap.algo = &muxc->algo;
        priv->adap.algo_data = priv;
        priv->adap.dev.parent = &parent->dev;
        priv->adap.retries = parent->retries;
diff --git a/include/linux/i2c-mux.h b/include/linux/i2c-mux.h
index bd74d5706f3b..5a4ffca99f5d 100644
--- a/include/linux/i2c-mux.h
+++ b/include/linux/i2c-mux.h
@@ -28,6 +28,7 @@
 #ifdef __KERNEL__
 
 #include <linux/bitops.h>
+#include <linux/i2c.h>
 
 struct i2c_mux_core {
        struct i2c_adapter *parent;
@@ -36,6 +37,7 @@ struct i2c_mux_core {
        unsigned int arbitrator:1;
        unsigned int gate:1;
 
+       struct i2c_algorithm algo;
        void *priv;
 
        int (*select)(struct i2c_mux_core *, u32 chan_id);
-- 
2.17.1

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