Issue 581: GTA04 GPS: rfkill missing

Reported by Nikolaus Schaller, Apr 10, 2014

* UART2 problem
* gpio-w2sg0004.c needs correct way to dynamically modify pinmux 
(replacement for omap_mux_set_gpio)
* something wrong in the DT plumbing for the driver
* rfkill has no visible effect

Comment 1 by Nikolaus Schaller, Jun 2, 2014

rfkill is now working and enables/disables the LNA power.
This could be verified by monitoring the 
/sys/class/regulator/regulator.*/state for the "vsim" 
regulator.

One thing should be improved: the LNA should stay powered off after 
booting to save energy. I.e. GPS should start up in the blocked 
state.

Comment 2 by Nikolaus Schaller, Aug 18, 2014

here is a description how drivers should choose between default and 
other pinmux states (through pinctrl_lookup_state and 
pinctrl_select_state):

https://www.kernel.org/doc/Documentation/pinctrl.txt

Focus on the sections "Pin control requests from drivers" 
"Runtime pinmuxing"

Comment 3 by Nikolaus Schaller, Sep 6, 2014

Fixed in 3.17-rc3!
Issues were multiple:
1. pinmux states have been defined as suggested
2. the omap-serial.c DTR extension did lack code to set the 
DTR_present flag in the DT based platform data
3. some minor tweaks added

Comment 4 by Nikolaus Schaller, Sep 6, 2014

Status: Fixed

Comment 5 by Nikolaus Schaller, Sep 6, 2014

Status: Ready

Comment 6 by Nikolaus Schaller, Sep 6, 2014

Owner: marekb

Comment 7 by Nikolaus Schaller, Oct 22, 2014

discussion on LKML started.

Some minor feedbacks and one major issue:

it appears not to be acceptable to have this "virtual 
GPIO" type of interface. People want to see real hardware only 
in the DT.

Status: Submitted

Comment 8 by Marek Belisko, Feb 23, 2015

NeilBrown started pushing slave tty devices which maintainer seems 
to like. More info at: 
http://thread.gmane.org/gmane.linux.kernel/1849147

Comment 9 by Nikolaus Schaller, Dec 17, 2016

As of today, despite multiple attempts by different groups, we still 
have no tty-slaves in the kernel.
Of course we have our private solution which is tested, maintained 
by us and works. But it is completely sitting on top of mainline 
Linux.

Comment 10 by Nikolaus Schaller, Feb 16, 2019

Finally we have a serdev based solution in linux-next. It is only 
lacking the rfkill control.

Comment 11 by Nikolaus Schaller, Feb 16, 2019

Owner: andi

Comment 12 by Nikolaus Schaller, Jul 8, 2019

Labels: Priority:Medium Milestone:5.3 ~~Priority:Critical~~ ~~Milestone:3.15~~
Summary: GTA04 GPS: rfkill missing

Letux Kernel