i2c: mux: create "channel-n" symlinks for child segments in the mux device

This makes the topology clearer. For instance, by adding a pca9547
device with address 0x70 to bus i2c-0, you get:

/sys/class/i2c-dev/i2c-0/device/0-0070/channel-0 -> i2c-1
...
/sys/class/i2c-dev/i2c-0/device/0-0070/channel-7 -> i2c-8

Signed-off-by: Gerlando Falauto <gerlando.falauto@keymile.com>
[wsa: simplified sysfs-usage and fixed format string usage]
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Acked-by: Martin Belanger <martin.belanger@cyaninc.com>
Acked-by: Danielle Costantino <danielle.costantino@gmail.com>

1 files changed, 8 insertions, 0 deletions

diff --git a/drivers/i2c/i2c-mux.c b/drivers/i2c/i2c-mux.c
index f246a9f7dd22..593f7ca9adc7 100644
--- a/drivers/i2c/i2c-mux.c
+++ b/drivers/i2c/i2c-mux.c
@@ -110,6 +110,7 @@ struct i2c_adapter *i2c_add_mux_adapter(struct i2c_adapter *parent,
                                                  void *, u32))
 {
         struct i2c_mux_priv *priv;
+        char symlink_name[20];
         int ret;
 
         priv = kzalloc(sizeof(struct i2c_mux_priv), GFP_KERNEL);
@@ -186,6 +187,9 @@ struct i2c_adapter *i2c_add_mux_adapter(struct i2c_adapter *parent,
         WARN(sysfs_create_link(&priv->adap.dev.kobj, &mux_dev->kobj, "mux_device"),
                                "can't create symlink to mux device\n");
 
+        snprintf(symlink_name, sizeof(symlink_name), "channel-%u", chan_id);
+        WARN(sysfs_create_link(&mux_dev->kobj, &priv->adap.dev.kobj, symlink_name),
+                               "can't create symlink for channel %u\n", chan_id);
         dev_info(&parent->dev, "Added multiplexed i2c bus %d\n",
                  i2c_adapter_id(&priv->adap));
 
@@ -196,6 +200,10 @@ EXPORT_SYMBOL_GPL(i2c_add_mux_adapter);
 void i2c_del_mux_adapter(struct i2c_adapter *adap)
 {
         struct i2c_mux_priv *priv = adap->algo_data;
+        char symlink_name[20];
+
+        snprintf(symlink_name, sizeof(symlink_name), "channel-%u", priv->chan_id);
+        sysfs_remove_link(&adap->dev.parent->kobj, symlink_name);
 
         sysfs_remove_link(&priv->adap.dev.kobj, "mux_device");
         i2c_del_adapter(adap);