Re: [PATCH v2 1/3] dt-bindings: net: bluetooth: Add broadcom-bluetooth

Hi Maxime,


Am 22.08.2017 um 09:47 schrieb Maxime Ripard:

Hi Loic,

On Tue, Aug 01, 2017 at 10:38:22AM +0200, Loic Poulain 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

  .../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:
+
+ - max-speed: see Documentation/devicetree/bindings/serial/slave-device.txt
+
+Example:
+
+&uart2 {
+       pinctrl-names = "default";
+       pinctrl-0 = <&uart2_pins>;
+
+       bluetooth {
+               compatible = "brcm,bcm43438-bt";
+               max-speed = <921600>;
+       };
+};

Thanks a lot for working on that, I've made a similar attempt a few
weeks ago but didn't manage to get it to work.

The way it's hooked in our boards is a bit more complex though, even
if it could be because we're using a different part.

In order to get it running we need:
   - two clocks, called in the broadcom datasheets lpo and tcxo.
   - three GPIOs, device wakeup, host wakeup and a shutdown GPIO (which
     might be the BT_ON you were discussing about)
   - two regulators called vbat and reg-en for us (I guess they're
     meant to power the chip, and its registers)

Do you know if you're also using those? Or could it be that it's just
hardwired to some non-gatable crystal / regulator on the RPI?

unfortunately the Foundation doesn't provide the full schematics for RPI 
3 or RPI Zero W (which uses the same chip).

Please also take a look at the RPI Zero W device tree sources, which 
describe the wifi part of the chip [1]. It contains a line called WL_ON 
on gpio41 and the low power clock on gpio43.

Stefan

[1] - 
https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/tree/arch/arm/boot/dts/bcm2835-rpi-zero-w.dts?h=next-20170822

Thanks!
Maxime