linux-kernel - Re: [PATCH v2 03/10] pinctrl: axp209: use drv_data of pinctrl_pin

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Date:   Tue, 26 Sep 2017 15:17:05 +0200
From:   Quentin Schulz <quentin.schulz@...e-electrons.com>
To:     Maxime Ripard <maxime.ripard@...e-electrons.com>
Cc:     linus.walleij@...aro.org, robh+dt@...nel.org, mark.rutland@....com,
        wens@...e.org, linux@...linux.org.uk, lee.jones@...aro.org,
        linux-gpio@...r.kernel.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-sunxi@...glegroups.com, thomas.petazzoni@...e-electrons.com
Subject: Re: [PATCH v2 03/10] pinctrl: axp209: use drv_data of
 pinctrl_pin_desc to store pin reg

Hi Maxime,

On 26/09/2017 15:01, Maxime Ripard wrote:
> On Tue, Sep 26, 2017 at 12:17:13PM +0000, Quentin Schulz wrote:
>> Instead of using a function to retrieve each pin's correct control
>> register, use drv_data within pinctrl_pin_desc to store the ctrl reg.
>>
>> Remove axp20x_gpio_get_reg and replace every occurrence by a get from
>> drv_data.
> 
> Why do you need to do that? This should be explained.
> 

Agreed that it misses an explanation.

Today, to get a register addr of one of the GPIOs in the PMIC, we
basically get the GPIO number and returns the register via this info.

There are 3 GPIOs in AXP209, 2 in AXP813. I didn't want to have a switch
case for the GPIO number and then an if/else inside one of the case to
check if the device is AXP209 or AXP813 in which case we return -EINVAL
instead of the GPIO2 reg. With support for new PMIC, we would have a
bunch of if conditions and complexify the process for something really
simple.

IMHO, this also allows easier integration of future PMICs which might
have different regs for the GPIOs.

I don't *need* it but I find this solution nicer.

Thanks,
Quentin

-- 
Quentin Schulz, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com

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