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SubjectRe: [PATCH 1/2] Input: omap-keypad: Fix keyboard debounce configuration
On Sun, Dec 02, 2018 at 05:29:32PM -0800, Tony Lindgren wrote:
> 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.
>
> Cc: Axel Haslam <axelhaslam@ti.com>
> Cc: Felipe Balbi <felipe.balbi@linux.intel.com>
> Cc: Illia Smyrnov <illia.smyrnov@ti.com>
> Cc: Marcel Partap <mpartap@gmx.net>
> Cc: Merlijn Wajer <merlijn@wizzup.org>
> Cc: Michael Scott <hashcode0f@gmail.com>
> Cc: NeKit <nekit1000@gmail.com>
> Cc: Pavel Machek <pavel@ucw.cz>
> Cc: Sebastian Reichel <sre@kernel.org>
> Reported-by: Pavel Machek <pavel@ucw.cz>
> Signed-off-by: Tony Lindgren <tony@atomide.com>

Applied, thank you.

> ---
> drivers/input/keyboard/omap4-keypad.c | 18 ++++++++++++++----
> 1 file changed, 14 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/input/keyboard/omap4-keypad.c b/drivers/input/keyboard/omap4-keypad.c
> --- a/drivers/input/keyboard/omap4-keypad.c
> +++ b/drivers/input/keyboard/omap4-keypad.c
> @@ -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));
> --
> 2.19.2

--
Dmitry

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