Re: [PATCH v2] pinctrl: amd: print debounce filter info in debugfs

From: Coiby Xu
Date: Mon Oct 26 2020 - 19:16:54 EST


On Mon, Oct 26, 2020 at 05:22:45PM +0200, Andy Shevchenko wrote:
On Mon, Oct 26, 2020 at 5:16 PM Coiby Xu <coiby.xu@xxxxxxxxx> wrote:

Print the status of debounce filter as follows,
$ cat /sys/kernel/debug/gpio
pin129 interrupt is disabled| interrupt is masked| disable wakeup in S0i3 state| disable wakeup in S3 state|
disable wakeup in S4/S5 state| input is high| pull-up is disabled| Pull-down is disabled| output is disabled| debouncing filter disabled| 0x50000
pin130 interrupt is disabled| interrupt is masked| disable wakeup in S0i3 state| disable wakeup in S3 state|
disable wakeup in S4/S5 state| input is high| pull-up is disabled| Pull-down is disabled| output is disabled| debouncing filter (high) enabled| debouncing timeout is 124800 (us)| 0x503c8
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Thanks for an update!
In general looks good, one nit below (sorry, missed it in v1 round)

Thank you for the feedbacks!
...

+ char debounce_value[40];

(1)

...

+ if (tmr_large) {
+ if (tmr_out_unit)
+ unit = 62500;
+ else

+ unit = 15600;

Side note: Hmm... Shouldn't be 15625? As 1/4.

Thank you for discovering the inconsistency! I wrote these code based on
amd_gpio_set_debounce. I'll send an email to the original author to
confirm it.

static int amd_gpio_set_debounce(struct gpio_chip *gc, unsigned offset,
unsigned debounce)
{
...
if (debounce) {
pin_reg |= DB_TYPE_REMOVE_GLITCH << DB_CNTRL_OFF;
pin_reg &= ~DB_TMR_OUT_MASK;
/*
Debounce Debounce Timer Max
TmrLarge TmrOutUnit Unit Debounce
Time
0 0 61 usec (2 RtcClk) 976 usec
0 1 244 usec (8 RtcClk) 3.9 msec
1 0 15.6 msec (512 RtcClk) 250 msec
1 1 62.5 msec (2048 RtcClk) 1 sec
*/

if (debounce < 61) {
pin_reg |= 1;
pin_reg &= ~BIT(DB_TMR_OUT_UNIT_OFF);
pin_reg &= ~BIT(DB_TMR_LARGE_OFF);
} else if (debounce < 976) {
time = debounce / 61;
pin_reg |= time & DB_TMR_OUT_MASK;
pin_reg &= ~BIT(DB_TMR_OUT_UNIT_OFF);
pin_reg &= ~BIT(DB_TMR_LARGE_OFF);
...

+ } else {
+ if (tmr_out_unit)
+ unit = 244;
+ else
+ unit = 61;

...


+ snprintf(debounce_value, 40,
+ "debouncing timeout is %u (us)|", time * unit);

(2)

...

+ snprintf(debounce_value, 40, " ");

(3)

Because of definition (1) can you in (2) and (3) use sizeof() ?

I've considered defining a constant. Obviously sizeof is a better
idea:)

--
With Best Regards,
Andy Shevchenko

--
Best regards,
Coiby