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>

3 files changed, 4 insertions, 0 deletions

diff --git a/include/linux/i2c-mux-gpio.h b/include/linux/i2c-mux-gpio.h
index a36343a37ebc..4ea1cc7392bd 100644
--- a/include/linux/i2c-mux-gpio.h
+++ b/include/linux/i2c-mux-gpio.h
@@ -21,6 +21,7 @@
  * @values: Array of bitmasks of GPIO settings (low/high) for each
  *      position
  * @n_values: Number of multiplexer positions (busses to instantiate)
+ * @classes: Optional I2C auto-detection classes
  * @gpios: Array of GPIO numbers used to control MUX
  * @n_gpios: Number of GPIOs used to control MUX
  * @idle: Bitmask to write to MUX when idle or GPIO_I2CMUX_NO_IDLE if not used
@@ -30,6 +31,7 @@ struct i2c_mux_gpio_platform_data {
         int base_nr;
         const unsigned *values;
         int n_values;
+        const unsigned *classes;
         const unsigned *gpios;
         int n_gpios;
         unsigned idle;
diff --git a/include/linux/i2c-mux.h b/include/linux/i2c-mux.h
index c79083830014..40cb05a97b46 100644
--- a/include/linux/i2c-mux.h
+++ b/include/linux/i2c-mux.h
@@ -36,6 +36,7 @@
 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 *mux_dev, u32 chan_id),
                                 int (*deselect) (struct i2c_adapter *,
diff --git a/include/linux/i2c/pca954x.h b/include/linux/i2c/pca954x.h
index 28f1f8d5ab1f..1712677d5904 100644
--- a/include/linux/i2c/pca954x.h
+++ b/include/linux/i2c/pca954x.h
@@ -36,6 +36,7 @@
 struct pca954x_platform_mode {
         int             adap_id;
         unsigned int    deselect_on_exit:1;
+        unsigned int    class;
 };
 
 /* Per mux/switch data, used with i2c_register_board_info */