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>
diff --git a/drivers/i2c/i2c-mux.c b/drivers/i2c/i2c-mux.c
index 1038c38..d94e0ce 100644
--- a/drivers/i2c/i2c-mux.c
+++ b/drivers/i2c/i2c-mux.c
@@ -88,9 +88,23 @@
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 @@
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.
diff --git a/drivers/i2c/muxes/i2c-mux-gpio.c b/drivers/i2c/muxes/i2c-mux-gpio.c
index 68b1f8e..56889e0 100644
--- a/drivers/i2c/muxes/i2c-mux-gpio.c
+++ b/drivers/i2c/muxes/i2c-mux-gpio.c
@@ -104,8 +104,10 @@
for (i = 0; i < pdata->n_values; i++) {
u32 nr = pdata->base_nr ? (pdata->base_nr + i) : 0;
+ unsigned int class = pdata->classes ? pdata->classes[i] : 0;
- mux->adap[i] = i2c_add_mux_adapter(parent, &pdev->dev, mux, nr, i,
+ mux->adap[i] = i2c_add_mux_adapter(parent, &pdev->dev, mux, nr,
+ i, class,
i2c_mux_gpio_select, deselect);
if (!mux->adap[i]) {
ret = -ENODEV;
diff --git a/drivers/i2c/muxes/i2c-mux-pca9541.c b/drivers/i2c/muxes/i2c-mux-pca9541.c
index f8f72f3..f3b8f9a 100644
--- a/drivers/i2c/muxes/i2c-mux-pca9541.c
+++ b/drivers/i2c/muxes/i2c-mux-pca9541.c
@@ -354,7 +354,7 @@
if (pdata)
force = pdata->modes[0].adap_id;
data->mux_adap = i2c_add_mux_adapter(adap, &client->dev, client,
- force, 0,
+ force, 0, 0,
pca9541_select_chan,
pca9541_release_chan);
diff --git a/drivers/i2c/muxes/i2c-mux-pca954x.c b/drivers/i2c/muxes/i2c-mux-pca954x.c
index f2dfe0d..8e43872 100644
--- a/drivers/i2c/muxes/i2c-mux-pca954x.c
+++ b/drivers/i2c/muxes/i2c-mux-pca954x.c
@@ -186,7 +186,7 @@
{
struct i2c_adapter *adap = to_i2c_adapter(client->dev.parent);
struct pca954x_platform_data *pdata = client->dev.platform_data;
- int num, force;
+ int num, force, class;
struct pca954x *data;
int ret = -ENODEV;
@@ -216,18 +216,20 @@
/* Now create an adapter for each channel */
for (num = 0; num < chips[data->type].nchans; num++) {
force = 0; /* dynamic adap number */
+ class = 0; /* no class by default */
if (pdata) {
- if (num < pdata->num_modes)
+ if (num < pdata->num_modes) {
/* force static number */
force = pdata->modes[num].adap_id;
- else
+ class = pdata->modes[num].class;
+ } else
/* discard unconfigured channels */
break;
}
data->virt_adaps[num] =
i2c_add_mux_adapter(adap, &client->dev, client,
- force, num, pca954x_select_chan,
+ force, num, class, pca954x_select_chan,
(pdata && pdata->modes[num].deselect_on_exit)
? pca954x_deselect_mux : NULL);
diff --git a/drivers/i2c/muxes/i2c-mux-pinctrl.c b/drivers/i2c/muxes/i2c-mux-pinctrl.c
index 46a6697..5f097f3 100644
--- a/drivers/i2c/muxes/i2c-mux-pinctrl.c
+++ b/drivers/i2c/muxes/i2c-mux-pinctrl.c
@@ -221,7 +221,7 @@
(mux->pdata->base_bus_num + i) : 0;
mux->busses[i] = i2c_add_mux_adapter(mux->parent, &pdev->dev,
- mux, bus, i,
+ mux, bus, i, 0,
i2c_mux_pinctrl_select,
deselect);
if (!mux->busses[i]) {
diff --git a/include/linux/i2c-mux-gpio.h b/include/linux/i2c-mux-gpio.h
index a36343a3..4ea1cc7 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 @@
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 c790838..40cb05a 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 28f1f8d..1712677 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 */