Re: [PATCH v3 4/4] tty: serial: msm_geni_serial: Add serial driver support for GENI based QUP

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On 3/8/2018 3:32 PM, Stephen Boyd wrote:
Quoting Karthik Ramasubramanian (2018-03-07 22:06:29)


On 3/6/2018 2:45 PM, Stephen Boyd wrote:
Quoting Karthik Ramasubramanian (2018-03-05 16:51:23)
On 3/2/2018 3:11 PM, Stephen Boyd wrote:

Ok. I've seen similar designs in some mmc drivers. For example, you can
look at drivers/mmc/host/meson-gx-mmc.c and see that they register a
clk_ops and then just start using that clk directly from the driver.
There are also some helper functions for dividers that would hopefully
make the job of calculating the best divider easier.
Thanks for the pointers. I will take a look at it. In the meanwhile I
had discussions with our clock team. They pointed out that the register
to write the divider value here is outside the scope of clock controller
which makes it trickier to implement your suggestion. They are already
in the mailing list and we will discuss further and get back to you in
this regard.

Ok. Let me know if I can help answer any questions.
Ok.


Why are these noirq variants? Please add a comment.
The intention is to enable the console UART port usage as late as
possible in the suspend cycle. Hence noirq variants. I will add this as
a comment. Please let me know if the usage does not match the intention.

Hm.. Does no_console_suspend not work? Or not work well enough?
It works. When console suspend is disabled, the suspend operation does
not get triggered and the resume operation checks if the console suspend
is disabled and performs the needed thing.

Ok so then do we need the noirq variants? Or console suspend is special
enough for this to not matter?
I am a little confused as to whether you prefer the console to not suspend at all or you prefer the console suspend at an earlier stage than no_irq stage.

If it is former, then with the console_suspend_enabled flag set by default this seems the right thing to do. Atleast my understanding is that console is expecting the serial port to suspend as well.

If it is latter, then I will check the stage at which suspend_console() is initiated and can suspend the serial port after that.

Regards,
Karthik.
--
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