Re: [RFC PATCH 0/3] UART slave device bus

From: Linus Walleij
Date: Thu Aug 18 2016 - 09:12:38 EST


On Thu, Aug 18, 2016 at 3:14 AM, Rob Herring <robh@xxxxxxxxxx> wrote:

> Currently, devices attached via a UART are not well supported in the
> kernel. The problem is the device support is done in tty line disciplines,
> various platform drivers to handle some sideband, and in userspace with
> utilities such as hciattach.

Freaking *awesome* Rob, this really really needs to happen.
I'm very happy that you're driving this.

> This is functional with minimal testing using the loopback driver and
> pl011 (w/o DMA) UART under QEMU (modified to add a DT node for the slave
> device). It still needs lots of work and polish.

I have Bluetooth (HCI) over UART on the Nomadik and Ux500,
both with DMA support for the PL011 too. So I hope to be able
to utilize this.

(The HCI transport is then used for GPS, FM radio and whatnot
but that is another issue.)

Yours,
Linus Walleij