Re: [PATCH 2/3] ARM: dts: rk3288 Tinker Board (S) add wi-fi

[David Summers <beagleboard-8lkWs+DogrrqRUWtDFdff/XRex20P6io@public.gmane.org>]

Oh yes - didn't reply to the "chip_h", in asus patch called "chip_enable_h".

This is the <&gpio4 RK_PD3 GPIO_ACTIVE_LOW> IIRC. We could see that two 
pins were pulled. RK_PD3 and RK_PD4; but not knowing exactly why the 
pins were pulled, question is should they be separate?

We went the direction of putting both pins under wifi_enable.

Its not clear to me which is the least confusing, should wifi_enable 
need pulling two pins, or should there be an extra service 
"chip_enable_h" for the extra pin? Think our problem is we didn't see 
what "chip_enable_h" meant - the description doesn't help. Hence why we 
removed, and merged with wifi_enable ...

On 17/02/2019 14:32, Tony McKahan wrote:
> A similar configuration has been in use on Armbian images since kernel
> 4.14, but not in a clean enough format for submission. I will test
> this, but the only differences I see compared to ours are combination
> of the mystery "chip_h" power domain/reset with the Wifi one and the
> inclusion of sd_uhs_ddr50.
>
> -Tony
>
> On Sun, Feb 17, 2019 at 7:16 AM David Summers
> <beagleboard-8lkWs+DogrrqRUWtDFdff/XRex20P6io@public.gmane.org> wrote:
>> This patch adds the wifi to the ASUS Tinker Board (S) machines.
>>
>> Unfortunatly neither the Tinker Board nor the Tinker Board S schematic
>> indicate how the WiFi is wired up on these devices. The WiFi is
>> provided by the RTL8723BS device, that has sdio WiFi and UART
>> Bluetooth. This patch just adds the WiFi interface.
>>
>> With no schematic, most of the wiring has been derived from the ASUS
>> patch to Debian:
>>
>> https://github.com/TinkerBoard/debian_kernel/commit/6a3128ade33f758887048578ada61a4b7ab8e678
>>
>> In conjunction with the pin out of the RTL8723BS device:
>>
>> http://files.pine64.org/doc/datasheet/pine64/RTL8723BS.pdf
>> http://cit.odessa.ua/media/pdf/Intel-Compute-Stick/FN-Link_F23BDSM25-W1.pdf
>>
>> The only unusual part is that to bring the card up, both the pins
>> RK_PD3 and RK_PD4 need to be pulled. Why this needs to be done is not
>> clear, best explaination is that they are connected to the RTL8723BS
>> pins WL_DIS# and BT_DIS#, which the data sheet vaguely says:
>>
>> Shared with GPIO9 This Pin Can Externally Shutdown the RTL8723BS WLAN
>> function when BT_DISn is Pulled Low. When this pin deasserted, SDIO
>> interface will be disabled. This pin can also support the WLAN Ra
>> dio-off function with host interface remaining connected.
>>
>> Anyway extensive testing the TheSaint on ArchLinux Arm Forum
>>
>> https://archlinuxarm.org/forum/viewtopic.php?f=44&t=13064&start=120#p60548
>>
>> Signed-off-by: David Summers <beagleboard-8lkWs+DogrrqRUWtDFdff/XRex20P6io@public.gmane.org>
>> Signed-off-by: Stefan Wahren <stefan.wahren-eS4NqCHxEME@public.gmane.org>
>>
>> +
>> +       sdio_pwrseq: sdio-pwrseq {
>> +               compatible = "mmc-pwrseq-simple";
>> +               clocks = <&rk808 RK808_CLKOUT1>;
>> +               clock-names = "ext_clock";
>> +               pinctrl-names = "default";
>> +               pinctrl-0 = <&wifi_enable>;
>> +               reset-gpios = <&gpio4 RK_PD3 GPIO_ACTIVE_LOW>, <&gpio4 RK_PD4 GPIO_ACTIVE_LOW>;
>> +       };
>>
>> +
>> +       sdio {
>> +               wifi_enable: wifi-enable {
>> +                       rockchip,pins = <4 RK_PD3 RK_FUNC_GPIO &pcfg_pull_none>, <4 RK_PD4 RK_FUNC_GPIO &pcfg_pull_none>;
>> +               };
>> +       };