Hi Stanely,

On 2020-02-17 21:42, Can Guo wrote:

On 2020-02-17 21:34, Stanley Chu wrote:

quoted

Hi Can,

On Mon, 2020-02-17 at 21:22 +0800, Can Guo wrote:

quoted

On 2020-02-17 21:12, Stanley Chu wrote:

quoted

Hi Can,

quoted

quoted

 			} else if (!on && clki->enabled) {
 				clk_disable_unprepare(clki->clk);
+				wait_us = hba->dev_info.clk_gating_wait_us;
+				if (ref_clk && wait_us)
+					usleep_range(wait_us, wait_us + 10);

Hi St,anley,

If wait_us is 1us, it would be inappropriate to use usleep_range()
here.
You have checks of the delay in patch #2, but why it is not needed
here?

Thanks,
Can Guo.

You are right. I could make that delay checking as common function so
it
can be used here as well to cover all possible values.

Thanks for suggestion.
Stanley

Hi Stanley,

One more thing, as in patch #2, you have already added delays in your
ufshcd_vops_setup_clocks(OFF, PRE_CHANGE) path, plus this delay here,
don't you delay for 2*bRefClkGatingWaitTime in ufshcd_setup_clocks()?
As the delay added in your vops also delays the actions of turning
off all the other clocks in ufshcd_setup_clocks(), you don't need the
delay here again, do you agree?

MediaTek driver is not using reference clocks named as "ref_clk" 
defined
in device tree, thus the delay specific for "ref_clk" in
ufshcd_setup_clocks() will not be applied in MediaTek platform.

This patch is aimed to add delay for this kind of "ref_clk" used by 
any
future vendors.

Anyway thanks for the reminding : )

quoted

Thanks,
Can Guo.

Thanks,
Stanley

Hi Stanley,

Then we are unluckily hit by this change. We have ref_clk in DT, thus
this change would add unwanted delays to our platforms. but still we
disable device's ref_clk in vops. :)

Could you please hold on patch #1 first? I need sometime to have a
dicussion with my colleagues on this.

Thanks.
Can Guo.

Since we all need this delay here, how about put the delay in the
entrence of ufshcd_setup_clocks(), before vops_setup_clocks()?
If so, we can remove all the delays we added in our vops since the
delay anyways delays everything inside ufshcd_setup_clocks().

Meanwhile, if you want to modify the delay
(hba->dev_info.clk_gating_wait_us) for some reasons, say for specific
UFS devices, you still can do it in vops_apply_dev_quirks().

What do you say?

Thanks,
Can Guo.

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel