linux-kernel - Re: [PATCH 4/5] ARM: pxa168: added special case handler for keypad interrupts

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Message-ID: <AANLkTinEtFhC6kB3asuBXLxCgYf9yOTLTTwRQJXKcu2n@mail.gmail.com>
Date:	Tue, 31 Aug 2010 02:28:59 -0400
From:	"Mark F. Brown" <mark.brown314@...il.com>
To:	Haojian Zhuang <haojian.zhuang@...il.com>
Cc:	Eric Miao <eric.y.miao@...il.com>,
	Haojian Zhuang <haojian.zhuang@...vell.com>,
	linux-arm-kernel <linux-arm-kernel@...ts.infradead.org>,
	linux-kernel <linux-kernel@...r.kernel.org>,
	linux-input <linux-input@...r.kernel.org>
Subject: Re: [PATCH 4/5] ARM: pxa168: added special case handler for keypad interrupts

On Tue, Aug 31, 2010 at 12:53 AM, Haojian Zhuang
<haojian.zhuang@...il.com> wrote:
> On Thu, Aug 26, 2010 at 5:18 PM, Mark F. Brown <mark.brown314@...il.com> wrote:
>> Signed-off-by: Mark F. Brown <mark.brown314@...il.com>
>> ---
>>  arch/arm/mach-mmp/irq-pxa168.c |   23 ++++++++++++++++++++++-
>>  1 files changed, 22 insertions(+), 1 deletions(-)
>>
>> diff --git a/arch/arm/mach-mmp/irq-pxa168.c b/arch/arm/mach-mmp/irq-pxa168.c
>> index 52ff2f0..bfb0984 100644
>> --- a/arch/arm/mach-mmp/irq-pxa168.c
>> +++ b/arch/arm/mach-mmp/irq-pxa168.c
>> @@ -17,6 +17,8 @@
>>  #include <linux/io.h>
>>
>>  #include <mach/regs-icu.h>
>> +#include <mach/regs-apmu.h>
>> +#include <mach/cputype.h>
>>
>>  #include "common.h"
>>
>> @@ -42,6 +44,19 @@ static struct irq_chip icu_irq_chip = {
>>        .unmask = icu_unmask_irq,
>>  };
>>
>> +void handle_pxa168_keypad_irq(unsigned int irq, struct irq_desc *desc)
>> +{
>> +       uint32_t val;
>> +       uint32_t mask = APMU_PXA168_KP_WAKE_CLR;
>> +
>> +       /* clear keypad wake event */
>> +       val = __raw_readl(APMU_WAKE_CLR);
>> +       __raw_writel(val |  mask, APMU_WAKE_CLR);
>> +
>> +       /* handle irq */
>> +       handle_level_irq(irq, desc);
>> +}
>> +
>
> Why should you clear wakeup event status in IRQ handler? If system is
> resumed by keypad event, you should clear this wakeup source in resume
> code. I think that IRQ code should not be binded with wakeup event at
> here.
>
>>  void __init icu_init_irq(void)
>>  {
>>        int irq;
>> @@ -49,7 +64,13 @@ void __init icu_init_irq(void)
>>        for (irq = 0; irq < 64; irq++) {
>>                icu_mask_irq(irq);
>>                set_irq_chip(irq, &icu_irq_chip);
>> -               set_irq_handler(irq, handle_level_irq);
>> +
>> +               /* special handler for keypad */
>> +               if (cpu_is_pxa168() && irq == IRQ_PXA168_KEYPAD)
>> +                       set_irq_handler(irq, handle_pxa168_keypad_irq);
>> +               else
>> +                       set_irq_handler(irq, handle_level_irq);
>> +
>>                set_irq_flags(irq, IRQF_VALID);
>>        }
>>  }
>> --
>> 1.7.0.4
>>
>> --
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>>
>

Haojian, this is an usual case, but without that clear wake event you
will not be able to clear the keypad interrupt. For my push to open
source I re-wrote the workaround code and added it as a special case
IRQ handler. In the Marvell pxa168 code base it is actually located in
the keypad interrupt handler as the function clear_wakeup(). I felt it
was better to isolate this code in the mmp common code base instead.

Regards,
-- Mark
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