diff options
| author | Jean Delvare <khali@linux-fr.org> | 2012-10-05 22:23:51 +0200 |
|---|---|---|
| committer | Jean Delvare <khali@endymion.delvare> | 2012-10-05 22:23:51 +0200 |
| commit | eee543e8248150e8fb833943c71f40c7b1724600 (patch) | |
| tree | 56efec8384b2bca4cf926583b52a7cf6136fa76f /drivers/i2c/i2c-mux.c | |
| parent | 5f3d2f2e1a63679cf1c4a4210f2f1cc2f335bef6 (diff) | |
i2c-mux: Add support for device auto-detection
Let I2C bus segments behind multiplexers have a class. This allows for
device auto-detection on these segments. As long as parent segments
don't share the same class, it should be fine.
I implemented support in drivers i2c-mux-gpio and i2c-mux-pca954x. I
left i2c-mux-pca9541 and i2c-mux-pinctrl alone for the moment as I
don't know if this feature makes sense for the use cases of these
drivers.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Cc: Peter Korsgaard <peter.korsgaard@barco.com>
Cc: David Daney <david.daney@cavium.com>
Cc: Michael Lawnick <ml.lawnick@gmx.de>
Cc: Rodolfo Giometti <giometti@linux.it>
Diffstat (limited to 'drivers/i2c/i2c-mux.c')
| -rw-r--r-- | drivers/i2c/i2c-mux.c | 22 |
1 files changed, 22 insertions, 0 deletions
diff --git a/drivers/i2c/i2c-mux.c b/drivers/i2c/i2c-mux.c index 1038c381aea..d94e0ce7827 100644 --- a/drivers/i2c/i2c-mux.c +++ b/drivers/i2c/i2c-mux.c @@ -88,9 +88,23 @@ static u32 i2c_mux_functionality(struct i2c_adapter *adap) return parent->algo->functionality(parent); } +/* Return all parent classes, merged */ +static unsigned int i2c_mux_parent_classes(struct i2c_adapter *parent) +{ + unsigned int class = 0; + + do { + class |= parent->class; + parent = i2c_parent_is_i2c_adapter(parent); + } while (parent); + + return class; +} + struct i2c_adapter *i2c_add_mux_adapter(struct i2c_adapter *parent, struct device *mux_dev, void *mux_priv, u32 force_nr, u32 chan_id, + unsigned int class, int (*select) (struct i2c_adapter *, void *, u32), int (*deselect) (struct i2c_adapter *, @@ -127,6 +141,14 @@ struct i2c_adapter *i2c_add_mux_adapter(struct i2c_adapter *parent, priv->adap.algo_data = priv; priv->adap.dev.parent = &parent->dev; + /* Sanity check on class */ + if (i2c_mux_parent_classes(parent) & class) + dev_err(&parent->dev, + "Segment %d behind mux can't share classes with ancestors\n", + chan_id); + else + priv->adap.class = class; + /* * Try to populate the mux adapter's of_node, expands to * nothing if !CONFIG_OF. |