Re: [PATCH v3 1/3] dt-bindings: net: bluetooth: Add broadcom-bluetooth

Rob Herring [off-list ref] writes:

On Mon, Aug 7, 2017 at 5:39 AM, Loic Poulain [off-list ref] wrote:

quoted

Add binding document for serial bluetooth chips using
Broadcom protocol.

Signed-off-by: Loic Poulain <redacted>
---
 v2: dt-bindings as separate patch
     rebase on upcoming pi3 dts changes
 v3: changes in bcm serdev drivers:
     name refactoring and additional comments
     Add generic host_set_baudrate method
     Use agnostic device_property_read
 .../devicetree/bindings/net/broadcom-bluetooth.txt | 29 ++++++++++++++++++++++
 1 file changed, 29 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/net/broadcom-bluetooth.txt

diff --git a/Documentation/devicetree/bindings/net/broadcom-bluetooth.txt b/Documentation/devicetree/bindings/net/broadcom-bluetooth.txt
new file mode 100644
index 0000000..c51ea1b
--- /dev/null
+++ b/Documentation/devicetree/bindings/net/broadcom-bluetooth.txt

@@ -0,0 +1,29 @@
+Broadcom Bluetooth Chips
+---------------------
+
+This documents the binding structure and common properties for serial
+attached Broadcom devices.
+
+Serial attached Broadcom devices shall be a child node of the host UART
+device the slave device is attached to.
+
+Required properties:
+
+ - compatible: should contain one of the following:
+   * "brcm,bcm43438-bt"
+
+Optional properties:

Most Broadcom devices have a couple of GPIOs needing control. Maybe
they are tied off active on RPi3, but you should document them here
even if the driver doesn't yet need them. I think they are the same as
the Nokia BT IIRC. Same goes for any input clocks.

As far as the clock goes, I think it would be a reference to <&cprman
BCM2835_CLOCK_GP2>, and the clock should be at 32Khz.  (This is already
set up at boot by the firmware).

In the schematics I have, there are two GPIO lines going to the chip:
BT_ON (expander gpio 0) and WL_ON (expander gpio 1).  We don't have
support for the expander yet, and they are already enabled at boot time,
so hopefully they can be optional properties.