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

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Date:	Mon, 24 Aug 2015 14:54:22 +0100
From:	Lee Jones <lee.jones@...aro.org>
To:	Vaibhav Hiremath <vaibhav.hiremath@...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 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;

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.

-- 
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog
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