linux-kernel - Re: [PATCH 1/3] drivers: pinctrl sleep and idle states in the core

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Date:	Tue, 11 Jun 2013 10:28:13 +0200
From:	Linus Walleij <linus.walleij@...aro.org>
To:	Stephen Warren <swarren@...dotorg.org>
Cc:	Linus Walleij <linus.walleij@...ricsson.com>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Stephen Warren <swarren@...dia.com>,
	Kevin Hilman <khilman@...aro.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"linux-arm-kernel@...ts.infradead.org" 
	<linux-arm-kernel@...ts.infradead.org>,
	Hebbar Gururaja <gururaja.hebbar@...com>,
	Mark Brown <broonie@...nel.org>,
	Dmitry Torokhov <dmitry.torokhov@...il.com>,
	Wolfram Sang <wsa@...-dreams.de>
Subject: Re: [PATCH 1/3] drivers: pinctrl sleep and idle states in the core

On Wed, Jun 5, 2013 at 7:22 PM, Stephen Warren <swarren@...dotorg.org> wrote:

>> diff --git a/drivers/pinctrl/core.c b/drivers/pinctrl/core.c
>
>> +int pinctrl_pm_select_default_state(struct device *dev)
>
>> +int pinctrl_pm_select_sleep_state(struct device *dev)
>
>> +int pinctrl_pm_select_idle_state(struct device *dev)
>
> The implementation of those 3 functions is basically identical. I'd be
> inclined to move it to a helper function, and just pass (dev,
> pins->xxx_state) to it.

Just to follow up on this now that I'm adding one more state.

I tried to create a refactoring patch for this but couldn't come
up with anything apropriate along the lines above. For example
this function:

int pinctrl_pm_select_default_state(struct device *dev)
{
        struct dev_pin_info *pins = dev->pins;
        int ret;

        if (!pins)
                return 0;
        if (IS_ERR(pins->default_state))
                return 0; /* No default state */
        ret = pinctrl_select_state(pins->p, pins->default_state);
        if (ret)
                dev_err(dev, "failed to activate default pinctrl state\n");
        return ret;
}

Would be refactored into something like this:

static int pinctrl_pm_select_state(struct device *dev, struct pinctrl_state *s)
{
        struct dev_pin_info *pins = dev->pins;

        if (IS_ERR(s))
                return 0;
        return pinctrl_select_state(pins->p, s);
}

int pinctrl_pm_select_default_state(struct device *dev)
{
        struct dev_pin_info *pins = dev->pins;
        int ret;

        if (!pins)
                return 0;
        if (IS_ERR(pins->default_state))
                return 0; /* No default state */
        ret = pinctrl_pm_select_state(dev, pins->default_state);
        if (ret)
                dev_err(dev, "failed to activate default pinctrl state\n");
        return ret;
}

That is not any elegant, I can cut down the lines by removing
debug messages but still we're dereferencing the pins twice and other
ugliness like that. Also pinctrl_pm_select_state() becomes more and more
a NULL wrapper around pinctrl_select_state() itself. If you have some other
suggestion or a patch ... I just can't see any elegant refactoring here.

Yours,
Linus Walleij
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