Add support for "i2c-mux-idle-disconnect" binding to match the
behavior, already present in upstream kernel driver. This feature is a
must have for I2C bus topologies with multiple muxes connected to
child segments containing slaves with identical addresses (e.g. ZII's
SCU4)
Signed-off-by: Andrey Smirnov <andrew.smirnov@xxxxxxxxx>
---
drivers/i2c/muxes/i2c-mux-pca954x.c | 19 ++++++++++++++++++-
1 file changed, 18 insertions(+), 1 deletion(-)
diff --git a/drivers/i2c/muxes/i2c-mux-pca954x.c b/drivers/i2c/muxes/i2c-mux-pca954x.c
index 42bde5ed1c..aa7dcb8c31 100644
--- a/drivers/i2c/muxes/i2c-mux-pca954x.c
+++ b/drivers/i2c/muxes/i2c-mux-pca954x.c
@@ -170,6 +170,16 @@ static int pca954x_select_chan(struct i2c_adapter *adap,
return ret;
}
+static int pca954x_deselect_chan(struct i2c_adapter *adap,
+ void *client, u32 chan)
+{
+ struct pca954x *data = i2c_get_clientdata(client);
+
+ /* Deselect active channel */
+ data->last_chan = 0;
+ return pca954x_reg_write(adap, client, data->last_chan);
+}
+
/*
* I2C init/probing/exit functions
*/
@@ -182,6 +192,7 @@ static int pca954x_probe(struct device_d *dev)
uintptr_t tmp;
int ret = -ENODEV;
int gpio;
+ bool idle_disconnect;
data = kzalloc(sizeof(struct pca954x), GFP_KERNEL);
if (!data) {
@@ -209,6 +220,9 @@ static int pca954x_probe(struct device_d *dev)
if (ret)
goto exit_free;
+ idle_disconnect = of_property_read_bool(dev->device_node,
+ "i2c-mux-idle-disconnect");
+
data->last_chan = 0; /* force the first selection */
/* Now create an adapter for each channel */
@@ -216,7 +230,10 @@ static int pca954x_probe(struct device_d *dev)
data->virt_adaps[num] =
i2c_add_mux_adapter(adap, &client->dev, client,
- 0, num, pca954x_select_chan, NULL);
+ 0, num, pca954x_select_chan,
+ idle_disconnect ?
+ pca954x_deselect_chan :
+ NULL);
if (data->virt_adaps[num] == NULL) {
ret = -ENODEV;
--
2.21.0
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