linux-kernel - Re: [PATCH V2 1/3] gpio: pca953x: make the register access by GPIO bank

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Date:	Tue, 08 Jan 2013 10:00:11 +0100
From:	Maxime Ripard <maxime.ripard@...e-electrons.com>
To:	Gregory CLEMENT <gregory.clement@...e-electrons.com>
CC:	Linus Walleij <linus.walleij@...aro.org>,
	Grant Likely <grant.likely@...retlab.ca>,
	Andreas Schallenberg <Andreas.Schallenberg@...itytechnica.com>,
	Roland Stigge <stigge@...com.de>,
	Jason Cooper <jason@...edaemon.net>,
	Andrew Lunn <andrew@...n.ch>,
	Thomas Petazzoni <thomas.petazzoni@...e-electrons.com>,
	Sebastian Hesselbarth <sebastian.hesselbarth@...il.com>,
	linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH V2 1/3] gpio: pca953x: make the register access by GPIO
 bank

Hi Gregory,

On 08/01/2013 09:58, Gregory CLEMENT wrote:
> On 01/08/2013 09:32 AM, Maxime Ripard wrote:
>> On 07/01/2013 23:51, Gregory CLEMENT wrote:
>>>  static irqreturn_t pca953x_irq_handler(int irq, void *devid)
>>>  {
>>>  	struct pca953x_chip *chip = devid;
>>> -	u32 pending;
>>> -	u32 level;
>>> +	u8 pending[MAX_BANK];
>>> +	u8 level;
>>> +	int i;
>>>  
>>> -	pending = pca953x_irq_pending(chip);
>>> -
>>> -	if (!pending)
>>> +	if (!pca953x_irq_pending(chip, pending))
>>>  		return IRQ_HANDLED;
>>>  
>>> -	do {
>>> -		level = __ffs(pending);
>>> -		handle_nested_irq(irq_find_mapping(chip->domain, level));
>>> -
>>> -		pending &= ~(1 << level);
>>> -	} while (pending);
>>> +	for (i = 0; i < NBANK(chip); i++) {
>>> +		do {
>>> +			level = __ffs(pending[i]);
>>> +			handle_nested_irq(irq_find_mapping(chip->domain,
>>> +							level + (BANK_SZ * i)));
>>> +			pending[i] &= ~(1 << level);
>>> +		} while (pending[i]);
>>> +	}
>>>  
>>>  	return IRQ_HANDLED;
>>>  }
>>
>> This triggers the following warning when an interrupt is raised:
>>
>> [   30.773500] ------------[ cut here ]------------
>> [   30.778843] WARNING: at /home/tmp/linux/kernel/irq/irqdomain.c:137 irq_domain_legacy_revmap+0x2c/0x48()
>> [   30.788375] Modules linked in:
>> [   30.791531] [<c0014100>] (unwind_backtrace+0x0/0xf0) from [<c001c878>] (warn_slowpath_common+0x4c/0x64)
>> [   30.801125] [<c001c878>] (warn_slowpath_common+0x4c/0x64) from [<c001c8ac>] (warn_slowpath_null+0x1c/0x24)
>> [   30.810968] [<c001c8ac>] (warn_slowpath_null+0x1c/0x24) from [<c006b5e0>] (irq_domain_legacy_revmap+0x2c/0x48)
>> [   30.821187] [<c006b5e0>] (irq_domain_legacy_revmap+0x2c/0x48) from [<c01c3734>] (pca953x_irq_handler+0x16c/0x1ac)
>> [   30.831656] [<c01c3734>] (pca953x_irq_handler+0x16c/0x1ac) from [<c0068688>] (irq_thread+0xd0/0x124)
>> [   30.841000] [<c0068688>] (irq_thread+0xd0/0x124) from [<c003c238>] (kthread+0xa4/0xb0)
>> [   30.849125] [<c003c238>] (kthread+0xa4/0xb0) from [<c000ed48>] (ret_from_fork+0x14/0x2c)
>> [   30.857375] ---[ end trace 09584b7a73100a49 ]---
>>
> 
> Humm it seems that this warning is caused by attempting to use an out of range hwirq.
> I need to investigate it more in details.
> 
> Expect the IRQ part, is this version is working for your gpio expander?

Yes, it works fine if you leave the interruptions aside.

Maxime

-- 
Maxime Ripard, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com
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