Hi Rob,

Ping on this. Have you seen my comments below?
I am trying to understand if fixing the smaller comments discussed below would allow this 
patch-set to be accepted so we at least have a working support as with previous kernels?
Or do we basically drop support for ti_st until it is implemented as a slave device?

Can you please let me know your thoughts?

Best Regards,
Eyal

-----Original Message-----
From: Reizer, Eyal
Sent: Sunday, January 17, 2016 9:57 AM
To: 'Rob Herring'
Cc: devicetree at vger.kernel.org; linux-omap at vger.kernel.org; linux-arm-
kernel at lists.infradead.org; pawel.moll at arm.com; mark.rutland at arm.com;
ijc+devicetree at hellion.org.uk; galak at codeaurora.org; tony at atomide.com;
linux at arm.linux.org.uk; Balbi, Felipe
Subject: RE: [PATCH 1/3] ti-st: use device handles and add device tree binding

Sorry for the delayed response.

quoted

-----Original Message-----
From: Rob Herring [mailto:robh at kernel.org]
Sent: Tuesday, December 29, 2015 8:36 PM
To: Reizer, Eyal
Cc: devicetree at vger.kernel.org; linux-omap at vger.kernel.org; linux-arm-
kernel at lists.infradead.org; pawel.moll at arm.com; mark.rutland at arm.com;
ijc+devicetree at hellion.org.uk; galak at codeaurora.org; tony at atomide.com;
linux at arm.linux.org.uk
Subject: Re: [PATCH 1/3] ti-st: use device handles and add device tree
binding

On Wed, Dec 23, 2015 at 11:38:29AM +0000, Reizer, Eyal wrote:

quoted

- Add support for getting the platform data which includes the uart
  used and gpio pin used for enable from device tree.

- Fix the implementation for using device handle for the uart and
  gpiod for the enable pin, instead of device name (as string) used
  for the uart and pio number which are both bad practice.

Signed-off-by: Eyal Reizer <redacted>
---
 Documentation/devicetree/bindings/misc/ti-st.txt |   42 ++++++
 arch/arm/mach-omap2/pdata-quirks.c               |   16 ++-
 drivers/misc/ti-st/st_kim.c                      |  159 ++++++++++++++++------
 drivers/misc/ti-st/st_ll.c                       |   16 ++-
 include/linux/ti_wilink_st.h                     |   13 +-

I'd suggest you look at commit c0bd1b9e58959c5 (Revert "ti-st: add
device tree support") first.

quoted

 5 files changed, 190 insertions(+), 56 deletions(-)  create mode
100644 Documentation/devicetree/bindings/misc/ti-st.txt

diff --git a/Documentation/devicetree/bindings/misc/ti-st.txt

b/Documentation/devicetree/bindings/misc/ti-st.txt
new file mode 100644
index 0000000..4490da6

--- /dev/null
+++ b/Documentation/devicetree/bindings/misc/ti-st.txt

@@ -0,0 +1,42 @@
+TI Wilink 6/7/8 (wl12xx/wl18xx) Shared transport driver

Bindings shouldn't be describing drivers...

OK, understood

quoted

quoted

+
+TI?s Wireless Connectivity chips support Bluetooth (BT), WiFi, and
+GPS technology cores in a single die.
+
+Such a multi-core combo chip will be interfaced to the application
+processor using a single physical port (like UART).
+
+Shared Transport (ST) software enables BT and GPS protocols or
+software components to interact with their respective cores over
+single

physical port.

quoted

+ST uses logical channels, over physical transport, to communicate
+with individual cores.
+
+Logical channels 1, 2, 3, and 4 are used for BT packets, channel 8
+for FM, channel 9 for GPS and channels 30, 31, 32, and 33 are used
+for Chip Power Management (PM).

All this is irrelevant for a binding.

OK, understood

quoted

quoted

+
+This node provides properties for passing parameters to the ti
+shared transport driver.
+
+Required properties:
+ - compatible: should be the following:
+    * "kim" - ti-st parameters

Who is kim? Certainly not a description of a h/w block.

Not sure about the origin of this name but according to the following link:
http://processors.wiki.ti.com/index.php/Shared_Transport_Driver
KIM is "Kernel Initialization Manager" that enables communication with BT and
GPS cores.

quoted

quoted

+
+Optional properties:
+ - nshutdown-gpios : specifies attributes for gpio ping used for enabling
+	the bluetooth,gps and FM sub systems
+ - serial-device : the phandle for the phisical uart used for interacting
+ 	with the wilink device

There have been multiple discussions on serial slave devices recently.
I'm not going to accept any device binding without a common uart slave
device binding first.

Perhaps I am reading it wrong but I think this is a different discussion.
The shared transport driver is already in the kernel for pretty long time.
AFAIK the original author is not around to maintain it.
Currently it is useless  as no bindings exist for it and all customers I have seen
using ti_st that upgrade to newer kernels have broken support and have to
manually patch the kernel for adding bindings for it.

Having a new uart slave device that may provide similar functionality is a
different discussion as it would require a total different implementation.
But what do we do now with the implementation that is already there.
Don't we want it to work and at least have working bindings for it?

quoted

quoted

+ - flow_cntrl : Indicates if uart flow control is used
+ - flow_cntrl : uart baud rate in BPS

Typo here, but these should be part of a common serial slave binding.

Don't use '_' in property names.

Will fix this

quoted

quoted

+
+Example:
+
+kim {
+	compatible = "kim";
+	nshutdown-gpios = <&gpio3 21 GPIO_ACTIVE_HIGH>;
+	serial-device = <&uart1>;
+	flow_cntrl = <1>;
+	flow_cntrl = <3000000>;
+};
+

Best Regards,
Eyal