[PATCH 2/2] dt: bindings: Add binding for ESP8089 wifi chips

[Icenowy Zheng]

Hi,

08.08.2016, 15:34, "Hans de Goede" <hdegoede at redhat.com>:
> Hi,
>
> On 08-08-16 04:36, Icenowy Zheng wrote:
>>  08.08.2016, 02:58, "Hans de Goede" <hdegoede at redhat.com>:
>>>  The ESP8089 chips can mostly be enumerated via their sdio interface,
>>>  but they are clocked by an external crystal which may differ from one
>>>  board to the other.
>>>
>>>  This commit adds a binding for the sdio child node for these chips,
>>>  allowing to specify the external crystal type (for now, this binding
>>>  could be be extended with e.g. OOB irq support later).
>>>
>>>  The Android driver for this chip uses a text file with key,value pairs
>>>  which gets loaded as firmware to pass this info to the firmware.
>>>  The "esp,crystal_26M_en" name is chosen to match the crystal_26M_en
>>>  key-name in that text file.
>>>
>>>  Note that at this point there only is an out of tree driver for this
>>>  hardware, there is no clear timeline / path for merging this. Still
>>>  I believe it would be good to specify the binding for this in tree
>>>  now, so that any future migration to an in tree driver will not cause
>>>  compatiblity issues.
>>>
>>>  Cc: Icenowy Zheng <icenowy at aosc.xyz>
>>>  Signed-off-by: Hans de Goede <hdegoede at redhat.com>
>>>  ---
>>>   .../bindings/net/wireless/esp,esp8089.txt | 31 ++++++++++++++++++++++
>>>   1 file changed, 31 insertions(+)
>>>   create mode 100644 Documentation/devicetree/bindings/net/wireless/esp,esp8089.txt
>>>
>>>  diff --git a/Documentation/devicetree/bindings/net/wireless/esp,esp8089.txt b/Documentation/devicetree/bindings/net/wireless/esp,esp8089.txt
>>>  new file mode 100644
>>>  index 0000000..898a149
>>>  --- /dev/null
>>>  +++ b/Documentation/devicetree/bindings/net/wireless/esp,esp8089.txt
>>>  @@ -0,0 +1,31 @@
>>>  +Espressif ESP8089 wireless SDIO devices
>>>  +
>>>  +This node provides properties for controlling the ESP8089 wireless device.
>>>  +The node is expected to be specified as a child node to the SDIO controller
>>>  +that connects the device to the system.
>>>  +
>>>  +Required properties:
>>>  +
>>>  + - compatible : Should be "esp,esp8089".
>>  There's also esp8266. (And the difference of 8089 and 8266 is mainly the difference of crystal frequency... 26MHz for 8266, 40MHz for 8089)
>>  So maybe it should be the difference of dt compatible?
>
> 2 of my tablets (both Polaroid ones) use a value of 2 (rather
> then 0 or 1) for crystal_26M_en and using a different value
> does not work. Another generic q8 form-factor tablet I've with
> an a23 needs crystal_26M_en=1. In all these tablets the chip is
> clearly marked esp8089, so the crystal_26M_en setting seems to
> not be related to the chip model and deriving this from the
> compatible string seems like a bad idea to me.

Oh such strange.

Thanks,
Icenowy
>
> Regards,
>
> Hans
>
>>>  +
>>>  +Optional properties:
>>>  + - esp,crystal_26M_en: Integer value for the crystal_26M_en firmware parameter
>>>  +
>>>  +Example:
>>>  +
>>>  +&mmc1 {
>>>  + #address-cells = <1>;
>>>  + #size-cells = <0>;
>>>  +
>>>  + vmmc-supply = <&reg_dldo1>;
>>>  + mmc-pwrseq = <&wifi_pwrseq>;
>>>  + bus-width = <4>;
>>>  + non-removable;
>>>  + status = "okay";
>>>  +
>>>  + esp8089: sdio_wifi at 1 {
>>>  + compatible = "esp,esp8089";
>>>  + reg = <1>;
>>>  + esp,crystal_26M_en = <2>;
>>>  + };
>>>  +};
>>>  --
>>>  2.7.4