Re: [PATCH] clk: add gpio gated clock

From: Jyri Sarha
Date: Thu Sep 11 2014 - 04:44:12 EST


On 09/10/2014 01:14 AM, Mike Turquette wrote:
Quoting Jyri Sarha (2014-09-05 05:21:34)
The added gpio-gate-clock is a basic clock that can be enabled and
disabled trough a gpio output. The DT binding document for the clock
is also added. For EPROBE_DEFER handling the registering of the clock
has to be delayed until of_clk_get() call time.

Signed-off-by: Jyri Sarha <jsarha@xxxxxx>
---

This is my final attempt to get this generic gpio controlled basic
clock into mainline. Of course I gladly fix any issues that the patch
may have. However, if there is no response, I give up and move it to TI
specific clocks.


I searched through my archives and found a post from January. You Cc'd
me as "<mturquette@xxxxxxxxxx>". Note that the address is wrapped in
chevrons but there is no name string (e.g. "Mike Turquette").

My mailer doesn't parse this well it was not flagged as to:me in my
filters. Maybe other mailers handle this better? If you leave out the
name string in the future then it would probably be best to drop the
chevrons.


Then git send-email adds the chevrons, but in the future I'll put the name string there too.

I've been sending this patch as a part of Beaglebone-Black HDMI audio
patch series since last autumn. Since the previous version I have done
some minor cleanups and changed the clock's compatible property from
"gpio-clock" to "gpio-gate-clock". All the file names, comments,
etc. have also been changed accordingly.

Is your platform the only one to take advantage of this clock type so
far? I feel that it is esoteric enough that it shouldn't be made
generic.

The main reason is that all of the generic clock types needs to be
overhauled at some point. E.g. the clk-gate should have its
machine-specific logic separated from its machine-independent logic. If
the gate clock were to populate .enable and .disable callbacks and then
leave the actual register banging, or regmap'ing, or gpio'ing up to your
backend driver then that would be a big improvement and would avoid the
need to create this new clock type outright.

So that's on my todo list, but it's not done yet. For your patch I think
that putting this code into drivers/clk/ti would probably be best,
unless other folks could use it as-is. Even if others could use it today
I would want to remove it eventually for the reasons stated in the
paragraph above.


Ok, I see. I do not know of anybody else needing a gpio gate clock at the moment. I'll put the driver under drivers/clk/ti unless someone comes forward soon.

Thanks,
Jyri

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/