linux-kernel - Re: [PATCH-v6 5/6] mfd: 88pm800: Set default interrupt clear method

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Date:	Mon, 24 Aug 2015 20:50:07 +0530
From:	Vaibhav Hiremath <vaibhav.hiremath@...aro.org>
To:	Lee Jones <lee.jones@...aro.org>
CC:	linux-arm-kernel@...ts.infradead.org, Zhao Ye <zhaoy@...vell.com>,
	Samuel Ortiz <sameo@...ux.intel.com>,
	open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH-v6 5/6] mfd: 88pm800: Set default interrupt clear method



On Monday 24 August 2015 07:24 PM, Lee Jones wrote:
> On Wed, 08 Jul 2015, Vaibhav Hiremath wrote:
>
>> As per the spec, bit 1 (INT_CLEAR_MODE) of reg addr 0xe
>> (page 0) controls the method of clearing interrupt
>> status of 88pm800 family of devices;
>>
>>    0: clear on read
>>    1: clear on write
>>
>> If pdata is not coming from board file, then set the
>> default irq clear method to "irq clear on write"
>>
>> Also, as suggested by "Lee Jones" renaming variable field
>> to appropriate name and removed unnecessary field
>> pm80x_chip.irq_mode, using platform_data.irq_clr_method.
>>
>> Signed-off-by: Zhao Ye <zhaoy@...vell.com>
>> Signed-off-by: Vaibhav Hiremath <vaibhav.hiremath@...aro.org>
>> Reviewed-by: Krzysztof Kozlowski <k.kozlowski@...sung.com>
>> ---
>>   drivers/mfd/88pm800.c       | 15 ++++++++++-----
>>   include/linux/mfd/88pm80x.h |  9 +++++++--
>>   2 files changed, 17 insertions(+), 7 deletions(-)
>
> [...]
>
>> +#define PM800_WAKEUP2_INT_READ_CLEAR	(0 << 1)
>> +#define PM800_WAKEUP2_INT_WRITE_CLEAR	(1 << 1)
>
> Use BIT().
>
>> +/* Used by irq_clr_method */
>> +#define PM800_IRQ_CLR_ON_READ	0
>> +#define PM800_IRQ_CLR_ON_WRITE	1
>
>> -	int irq_mode;		/* Clear interrupt by read/write(0/1) */
>> +	bool irq_clr_method;		/* Clear interrupt by read/write(0/1) */
>
>> +	irq_clr_mode = pdata->irq_clr_method == PM800_IRQ_CLR_ON_WRITE ?
>> +		PM800_WAKEUP2_INT_WRITE_CLEAR : PM800_WAKEUP2_INT_READ_CLEAR;
>> +	ret = regmap_update_bits(map, PM800_WAKEUP2, mask, irq_clr_mode);
>
> This is pretty convoluted.
>
> For starters you're abusing the 'bool' type here.  Bool is either
> 'true' or 'false', so at the very least you should rename
> 'irq_clr_method' to 'irq_clr_on_write'.
>
> Then you can do:
>
> 	irq_clr_mode = pdata->irq_clr_on_write ?
> 		PM800_WAKEUP2_INT_WRITE_CLEAR : PM800_WAKEUP2_INT_READ_CLEAR;
>

We have discussed on this, and went back-n-forth.
I think if I remember correctly, one of the version was using
true/false then we decided to rename it to relevant macro.

If I am not wrong V4 version of this series is exactly same as what you
are referring to.


> However, what I suggest you really do is share
> PM800_WAKEUP2_INT_{READ,WRITE}_CLEAR with platform data and just pass
> the value through directly.
>

I think we discussed about this also, and the reason I recall here is,

we may need to control this from DT in the future so we decided to keep
it boolean in platform_data and have simple check before writing to
register.

And I think that was also another reason we introduced

/* Used by irq_clr_method */
#define PM800_IRQ_CLR_ON_READ   0
#define PM800_IRQ_CLR_ON_WRITE  1

(Earlier it was true/false in V4)

Thanks,
Vaibhav
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