ASoC: Amstrad Delta: add info about the line discipline requirement to Kconfig help text

I thought it could be usefull to add some information on how to get the device
fully supported by loading a line discipline on the modem line.

Signed-off-by: Janusz Krzysztofik <jkrzyszt@tis.icnet.pl>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

1 files changed, 12 insertions, 1 deletions

diff --git a/sound/soc/omap/Kconfig b/sound/soc/omap/Kconfig
index 2dee9839be86..653a362425df 100644
--- a/sound/soc/omap/Kconfig
+++ b/sound/soc/omap/Kconfig
@@ -21,7 +21,18 @@ config SND_OMAP_SOC_AMS_DELTA
         select SND_OMAP_SOC_MCBSP
         select SND_SOC_CX20442
         help
-          Say Y if you want to add support for SoC audio on Amstrad Delta.
+          Say Y  if you want to add support  for SoC audio device  connected to
+          a handset and a speakerphone found on Amstrad E3 (Delta) videophone.
+
+          Note that in order to get those devices fully supported,  you have to
+          build  the kernel  with  standard  serial port  driver  included  and
+          configured for at least 4 ports.  Then, from userspace, you must load
+          a line discipline #19 on the modem (ttyS3) serial line.  The simplest
+          way to achieve this is to install util-linux-ng  and use the included
+          ldattach  utility.  This  can be  started  automatically  from  udev,
+          a simple rule like this one should do the trick (it does for me):
+                ACTION=="add", KERNEL=="controlC0", \
+                                RUN+="/usr/sbin/ldattach 19 /dev/ttyS3"
 
 config SND_OMAP_SOC_OSK5912
         tristate "SoC Audio support for omap osk5912"