On Wed, May 4, 2022 at 11:04 AM Hakan Jansson
<[email protected]> wrote:
> + brcm,uses-autobaud-mode:
> + type: boolean
> + description: >
> + The controller should be started in autobaud mode by asserting
> + BT_UART_CTS_N (i.e. host RTS) during startup. Only HCI commands supported
> + in autobaud mode should be used until patch FW has been loaded.
Things like gnss uses the current-speed attribute to set a serial link speed,
maybe also Bluetooth?
Would it make sense to use
current-speed-auto;
As a flag for these things in general?
Yours,
Linus Walleij
Hi Linus,
Thanks for responding.
On 5/5/2022 12:15 AM, Linus Walleij wrote:
> On Wed, May 4, 2022 at 11:04 AM Hakan Jansson
> <[email protected]> wrote:
>
>> + brcm,uses-autobaud-mode:
>> + type: boolean
>> + description: >
>> + The controller should be started in autobaud mode by asserting
>> + BT_UART_CTS_N (i.e. host RTS) during startup. Only HCI commands supported
>> + in autobaud mode should be used until patch FW has been loaded.
> Things like gnss uses the current-speed attribute to set a serial link speed,
> maybe also Bluetooth?
As far as I can tell, not many Bluetooth drivers use the current-speed
attribute yet but perhaps it would be a good idea to start using it more
broadly in the future to set the initial serial link speed.
>
> Would it make sense to use
>
> current-speed-auto;
>
> As a flag for these things in general?
I suppose a general flag could be useful but to be honest I don't know
if any other devices besides the ones using the Broadcom driver has any
use for it. You would probably also still want to be able to use
current-speed to set the link speed and end up using both
current-speed=x and current-speed-auto at the same time, which might
look a little confusing?
Please let me know if you'd still prefer "current-speed-auto" over
"brcm,uses-autobaud-mode" and I'll revise the patch and rename it!
>
> Yours,
> Linus Walleij
Thanks,
Håkan
On Thu, May 5, 2022 at 3:11 PM Hakan Jansson <[email protected]> wrote:
> I suppose a general flag could be useful but to be honest I don't know
> if any other devices besides the ones using the Broadcom driver has any
> use for it. You would probably also still want to be able to use
> current-speed to set the link speed and end up using both
> current-speed=x and current-speed-auto at the same time, which might
> look a little confusing?
I do not think it is more confusing than being able to use
current-speed and brcm,uses-autobaud-mode at the same time.
> Please let me know if you'd still prefer "current-speed-auto" over
> "brcm,uses-autobaud-mode" and I'll revise the patch and rename it!
It actually depends a bit.
This:
> >> + The controller should be started in autobaud mode by asserting
> >> + BT_UART_CTS_N (i.e. host RTS) during startup. Only HCI commands supported
> >> + in autobaud mode should be used until patch FW has been loaded.
sounds a bit vague?
Does it mean that CTS is asserted, then you send a bit (CTS then goes low)
and then CTS is asserted again when the device is ready to receieve more
data? i.e is this some kind of one-bit mode, because it doesn't sound like
it is using CTS as it was used in legacy modems.
Some more explanation of this mode is needed so we can understand if
this is something generic or a BRCM-only thing.
Yours,
Linus Walleij