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Input: omap-keypad - fix keyboard debounce configuration

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I noticed that the Android v3.0.8 kernel on droid4 is using different
keypad values from the mainline kernel and does not have issues with
keys occasionally being stuck until pressed again. Turns out there was
an earlier patch posted to fix this as "Input: omap-keypad: errata i689:
Correct debounce time", but it was never reposted to fix use macros
for timing calculations.

This updated version is using macros, and also fixes the use of the
input clock rate to use 32768KiHz instead of 32000KiHz. And we want to
use the known good Android kernel values of 3 and 6 instead of 2 and 6
in the earlier patch.

Reported-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
This commit is contained in:
Tony Lindgren 2018-12-03 11:24:30 -08:00 committed by Dmitry Torokhov
parent a6754fae1e
commit 6c3516fed7
1 changed files with 14 additions and 4 deletions
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18
drivers/input/keyboard/omap4-keypad.c
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@ -60,8 +60,18 @@
/* OMAP4 values */
#define OMAP4_VAL_IRQDISABLE 0x0
#define OMAP4_VAL_DEBOUNCINGTIME 0x7
#define OMAP4_VAL_PVT 0x7
/*
* Errata i689: If a key is released for a time shorter than debounce time,
* the keyboard will idle and never detect the key release. The workaround
* is to use at least a 12ms debounce time. See omap5432 TRM chapter
* "26.4.6.2 Keyboard Controller Timer" for more information.
*/
#define OMAP4_KEYPAD_PTV_DIV_128 0x6
#define OMAP4_KEYPAD_DEBOUNCINGTIME_MS(dbms, ptv) \
((((dbms) * 1000) / ((1 << ((ptv) + 1)) * (1000000 / 32768))) - 1)
#define OMAP4_VAL_DEBOUNCINGTIME_16MS \
OMAP4_KEYPAD_DEBOUNCINGTIME_MS(16, OMAP4_KEYPAD_PTV_DIV_128)
enum {
KBD_REVISION_OMAP4 = 0,
@ -181,9 +191,9 @@ static int omap4_keypad_open(struct input_dev *input)
kbd_writel(keypad_data, OMAP4_KBD_CTRL,
OMAP4_DEF_CTRL_NOSOFTMODE |
(OMAP4_VAL_PVT << OMAP4_DEF_CTRL_PTV_SHIFT));
(OMAP4_KEYPAD_PTV_DIV_128 << OMAP4_DEF_CTRL_PTV_SHIFT));
kbd_writel(keypad_data, OMAP4_KBD_DEBOUNCINGTIME,
OMAP4_VAL_DEBOUNCINGTIME);
OMAP4_VAL_DEBOUNCINGTIME_16MS);
/* clear pending interrupts */
kbd_write_irqreg(keypad_data, OMAP4_KBD_IRQSTATUS,
kbd_read_irqreg(keypad_data, OMAP4_KBD_IRQSTATUS));