Messages in this thread | | | Subject | Re: [PATCH 3/7] Input: ep93xx_keypad: Prepare clock before using it | From | Alexander Sverdlin <> | Date | Tue, 15 Jun 2021 09:46:51 +0200 |
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Hello Dmitry!
On Mon, 2021-06-14 at 14:55 -0700, Dmitry Torokhov wrote: > > Use clk_prepare_enable()/clk_disable_unprepare() in preparation for switch > > to Common Clock Framework. > > Can this be merged standalone?
In principle, yes, but I thought it would be easier if the patches would go via the same path as CCF conversion.
> > Signed-off-by: Alexander Sverdlin <alexander.sverdlin@gmail.com> > > --- > > drivers/input/keyboard/ep93xx_keypad.c | 4 ++-- > > 1 file changed, 2 insertions(+), 2 deletions(-) > > > > diff --git a/drivers/input/keyboard/ep93xx_keypad.c b/drivers/input/keyboard/ep93xx_keypad.c > > index c8194333d612..e0e931e796fa 100644 > > --- a/drivers/input/keyboard/ep93xx_keypad.c > > +++ b/drivers/input/keyboard/ep93xx_keypad.c > > @@ -157,7 +157,7 @@ static int ep93xx_keypad_open(struct input_dev *pdev) > > > > if (!keypad->enabled) { > > ep93xx_keypad_config(keypad); > > - clk_enable(keypad->clk); > > + clk_prepare_enable(keypad->clk); > > keypad->enabled = true; > > } > > > > @@ -169,7 +169,7 @@ static void ep93xx_keypad_close(struct input_dev *pdev) > > struct ep93xx_keypad *keypad = input_get_drvdata(pdev); > > > > if (keypad->enabled) { > > - clk_disable(keypad->clk); > > + clk_disable_unprepare(keypad->clk); > > keypad->enabled = false; > > While we are at it, I wonder about handling suspend/resume. I see that > we disable the clock even if keyboard is configured as a wakeup source. > Is it really capable of waking up the system when clock is off?
That what "EP93xx User’s Guide" says:
26.2.4 Low Power Mode The key scanning block also supports a low power wake-up mode. In this mode, a key press generates a wake up interrupt. The key scan interrupt should be masked. Because the wake up interrupt is asynchronous, and depends on external keypad lines which may have a large capacitance value, glitches may occur on the interrupt when transitioning to low power mode. After transitioning, all clocks to the key scanning circuitry can be shut down.
-- Alexander Sverdlin.
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