Fill the gap for this pre-existing driver.
Signed-off-by: Peter Rosin <peda@xxxxxxxxxx>
---
.../devicetree/bindings/i2c/i2c-arb-pca9541.txt | 33 ++++++++++++++++++++++
MAINTAINERS | 1 +
2 files changed, 34 insertions(+)
create mode 100644 Documentation/devicetree/bindings/i2c/i2c-arb-pca9541.txt
Hi!
I'm wondering about this driver. It is not a trivial device, and yet it
has historically relied on the i2c core matching the chip w/o vendor
prefix. This is not ideal. But what to do about the driver implementing
this in terms of an i2c-mux, somthing which the chip is not; It is an
i2c arbitrator. It just happens to rely on the i2c mux core also handling
i2c gates and i2c arbitrators. But that seems like a Linux detail. So I
don't know what to do here?
That is, the patch - as is - describes something that would be trivial to
support today, but at the same time it seems to be too tied to Linux.
The problem is that the i2c@0 intermediate node is not really needed, but
at the same time removing it would cause a disruption for the driver since
it can't really use the i2c mux core if that node isn't there. I don't
see a simple way to fix that in the i2c mux core either (but admittedly
haven't given it too much thought).
Any suggestions?
Cheers,
Peter
PS. The driver source is in drivers/i2c/muxes/i2c-mux-pca9541.c
diff --git a/Documentation/devicetree/bindings/i2c/i2c-arb-pca9541.txt b/Documentation/devicetree/bindings/i2c/i2c-arb-pca9541.txt
new file mode 100644
index 000000000000..edbe84935906
--- /dev/null
+++ b/Documentation/devicetree/bindings/i2c/i2c-arb-pca9541.txt
@@ -0,0 +1,33 @@
+* NXP PCA9541 I2C bus master selector
+
+Required Properties:
+
+ - compatible: Must be "nxp,pca9541"
+
+ - reg: The I2C address of the device.
+
+ The following required properties are defined externally:
+
+ - Standard I2C mux properties. See i2c-mux.txt in this directory.
+ - I2C child bus nodes. See i2c-mux.txt in this directory.
+
+
+Example:
+
+ i2c-arbitrator@74 {
+ compatible = "nxp,pca9541";
+ #address-cells = <1>;
+ #size-cells = <0>;
+ reg = <0x74>;
+
+ i2c@0 {
+ #address-cells = <1>;
+ #size-cells = <0>;
+ reg = <0>;
+
+ eeprom@54 {
+ compatible = "at,24c08";
+ reg = <0x54>;
+ };
+ };
+ };
diff --git a/MAINTAINERS b/MAINTAINERS
index e1b090f86e0d..3dd44d0d166c 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -5521,6 +5521,7 @@ S: Maintained
F: Documentation/i2c/i2c-topology
F: Documentation/i2c/muxes/
F: Documentation/devicetree/bindings/i2c/i2c-mux*
+F: Documentation/devicetree/bindings/i2c/i2c-arb*
F: drivers/i2c/i2c-mux.c
F: drivers/i2c/muxes/
F: include/linux/i2c-mux.h
--
2.1.4
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