Hi Sascha,
Sascha Hauer wrote:
Hi Andrey,
+Cc NeilBrown <neil@xxxxxxxxxx>
On Mon, Nov 16, 2015 at 07:24:58PM +0300, Andrey Vostrikov wrote:
Hi,
I have an embedded system with microcontroller connected via
UART/RS232 port. This microcontroller implements several low-level
functions that need to be exposed as device drivers in other
subsystems (watchdog, LEDs, HWMON, firmware read/write).
I checked many drivers implemented in the kernel, searched through
mail list archives and it looks like there are three different ways to
solve this task:
A) most of the devices that are connected using UART have user space
program that configures and manages it (either directly or with help
of dedicated line discipline, SLIP, SL-CAN, etc)
B) serio - mostly used for input devices
C) direct use of UART port taking control from serial_core.
The best match I have found so far is MFD driver for Atmel
Microcontroller on iPaq h3xxx (drivers/mfd/ipaq-micro.c) that follows
concept "C)"
There's also D) TTY slave device support: https://lkml.org/lkml/2015/3/18/40
Unfortunately this hasn't made it to mainline yet and it seems the
parties lost interest after some lengthy discussion of device tree phandles
vs. subnodes, but I think this is what you're looking for.
Thank you for pointing out to another option. Looks like it was developed a little further and was submitted as patch by "H. Nikolaus Schaller",
https://lkml.org/lkml/2015/10/16/729
But I see no further traces of it.
Cc'ed Nikolaus, may be he could comment on state of UART slave patch.
Best regards,
Andrey
Sascha
--
To unsubscribe from this list: send the line "unsubscribe linux-embedded" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
