Re: [PATCH 2/4] i3c: mipi-i3c-hci: Fix handling status of i3c_hci_irq_handler()

[Jarkko Nikula <jarkko.nikula@linux.intel.com>]

Hi

On 2/28/25 6:14 PM, Frank Li wrote:
> On Fri, Feb 28, 2025 at 04:18:00PM +0200, Jarkko Nikula wrote:
>> Return IRQ_HANDLED from the i3c_hci_irq_handler() only if some
>> INTR_STATUS bit was set or if DMA/PIO handler handled it.
>>
>> Currently it returns IRQ_HANDLED in case INTR_STATUS is zero and IO
>> handler returns false. Which could be the case if interrupt comes from
>> other device or is spurious.
>>
>> Signed-off-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
>> ---
>>   drivers/i3c/master/mipi-i3c-hci/core.c | 6 +++---
>>   1 file changed, 3 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/i3c/master/mipi-i3c-hci/core.c b/drivers/i3c/master/mipi-i3c-hci/core.c
>> index e139d7e4d252..e5593b6e897e 100644
>> --- a/drivers/i3c/master/mipi-i3c-hci/core.c
>> +++ b/drivers/i3c/master/mipi-i3c-hci/core.c
>> @@ -594,6 +594,7 @@ static irqreturn_t i3c_hci_irq_handler(int irq, void *dev_id)
>>
>>   	if (val) {
>>   		reg_write(INTR_STATUS, val);
>> +		result = IRQ_HANDLED;
> 
> Not related this patch.
> reg_write(INTR_STATUS, val); should be unconditional since INTR_STATUS is
> w1c.
> 
> I am strange why need return IRQ_NONE case. I suppose it should always
> return IRQ_HANDLED.
> 
This makes driver more ready for shared interrupts and let kernel 
interrupt code be able to disable bad behaving interrupt (misrouted, 
wrong polarity, etc) by returning IRQ_NONE when we know interrupt wasn't 
generated by this device.

Currently driver doesn't support shared interrupts since IRQF_SHARED 
flag is not passed to the devm_request_irq() call in i3c_hci_probe(). I 
didn't change that since I don't have a setup to test.

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