[PATCH] i2c: mux: remove duplicated i2c_algorithm

[PATCH] i2c: mux: remove duplicated i2c_algorithm

[Luca Ceresoli]

From: Luca Ceresoli <luca@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 <luca@lucaceresoli.net>
---
 drivers/i2c/i2c-mux.c   | 37 ++++++++++++++++++-------------------
 include/linux/i2c-mux.h |  1 +
 2 files changed, 19 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..d60b6846ca88 100644
--- a/include/linux/i2c-mux.h
+++ b/include/linux/i2c-mux.h
@@ -36,6 +36,7 @@ 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

Re: [PATCH] i2c: mux: remove duplicated i2c_algorithm

[kbuild test robot]

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Hi Luca,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on linus/master]
[also build test ERROR on v4.19-rc5 next-20180926]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Luca-Ceresoli/i2c-mux-remove-duplicated-i2c_algorithm/20180926-200605
config: x86_64-randconfig-u0-09270057 (attached as .config)
compiler: gcc-5 (Debian 5.5.0-3) 5.4.1 20171010
reproduce:
        # save the attached .config to linux build tree
        make ARCH=x86_64 

All errors (new ones prefixed by >>):

   In file included from drivers/i2c/muxes/i2c-mux-ltc4306.c:15:0:
>> include/linux/i2c-mux.h:39:23: error: field 'algo' has incomplete type
     struct i2c_algorithm algo;
                          ^

vim +/algo +39 include/linux/i2c-mux.h

    31	
    32	struct i2c_mux_core {
    33		struct i2c_adapter *parent;
    34		struct device *dev;
    35		unsigned int mux_locked:1;
    36		unsigned int arbitrator:1;
    37		unsigned int gate:1;
    38	
  > 39		struct i2c_algorithm algo;
    40		void *priv;
    41	
    42		int (*select)(struct i2c_mux_core *, u32 chan_id);
    43		int (*deselect)(struct i2c_mux_core *, u32 chan_id);
    44	
    45		int num_adapters;
    46		int max_adapters;
    47		struct i2c_adapter *adapter[0];
    48	};
    49	

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

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