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SubjectRe: [PATCH 2/2] Input: omap-keypad: Cleanup - remove unnecessary IRQ enabling/disabling
Hi,

On Fri, Jul 19, 2013 at 04:03:47PM +0300, Illia Smyrnov wrote:
> From: Illia Smyrnov <illia.smyrnov@ti.com>
>
> Remove unnecessary IRQ enabling/disabling for certain keyboard events.
>
> Signed-off-by: Illia Smyrnov <illia.smyrnov@ti.com>
> ---
> drivers/input/keyboard/omap4-keypad.c | 15 ++++-----------
> 1 files changed, 4 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/input/keyboard/omap4-keypad.c b/drivers/input/keyboard/omap4-keypad.c
> index c727548..73813b6 100644
> --- a/drivers/input/keyboard/omap4-keypad.c
> +++ b/drivers/input/keyboard/omap4-keypad.c
> @@ -121,10 +121,6 @@ static irqreturn_t omap4_keypad_interrupt(int irq, void *dev_id)
> unsigned int col, row, code, changed;
> u32 *new_state = (u32 *) key_state;
>
> - /* Disable interrupts */
> - kbd_write_irqreg(keypad_data, OMAP4_KBD_IRQENABLE,
> - OMAP4_VAL_IRQDISABLE);
> -
> *new_state = kbd_readl(keypad_data, OMAP4_KBD_FULLCODE31_0);
> *(new_state + 1) = kbd_readl(keypad_data, OMAP4_KBD_FULLCODE63_32);
>
> @@ -154,11 +150,6 @@ static irqreturn_t omap4_keypad_interrupt(int irq, void *dev_id)
> kbd_write_irqreg(keypad_data, OMAP4_KBD_IRQSTATUS,
> kbd_read_irqreg(keypad_data, OMAP4_KBD_IRQSTATUS));
>
> - /* enable interrupts */
> - kbd_write_irqreg(keypad_data, OMAP4_KBD_IRQENABLE,
> - OMAP4_DEF_IRQENABLE_EVENTEN |
> - OMAP4_DEF_IRQENABLE_LONGKEY);
> -

please don't remove this code. It'll be good to have this around when we
move the driver to threaded IRQs without IRQF_ONESHOT. In fact, it would
be very simple to implement such a change, wanna take it up ?

It should be doable in few patches:

1) switch over to request_threaded_irq()

just blind move to a thread, without hardirq handler, so
IRQF_ONESHOT is mandatory.

2) add hardirq handler

read IRQSTATUS to check if our device has generated IRQs
returning IRQ_WAKE_THREAD if true

3) move 'IRQ masking logic' to hardirq handler, before returning
IRQ_WAKE_THREAD

this will let you remove IRQF_ONESHOT

4) finally remove IRQF_ONESHOT

this makes sure that IRQs aren't kept disabled until we have
time to iterate over the entire keypad matrix. Only the keypad
IRQ will be masked.

--
balbi
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