linux-kernel - Re: [PATCH v3 2/3] gpiolib: Support 'gpio-reserved-ranges' property

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Date:   Wed, 21 Mar 2018 19:59:10 +0200
From:   Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To:     Stephen Boyd <swboyd@...omium.org>,
        Linus Walleij <linus.walleij@...aro.org>
Cc:     Stephen Boyd <sboyd@...eaurora.org>, linux-kernel@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, devicetree@...r.kernel.org,
        linux-arm-msm@...r.kernel.org, Timur Tabi <timur@...eaurora.org>,
        Bjorn Andersson <bjorn.andersson@...aro.org>,
        Grant Likely <grant.likely@...retlab.ca>,
        linux-gpio@...r.kernel.org
Subject: Re: [PATCH v3 2/3] gpiolib: Support 'gpio-reserved-ranges' property

On Wed, 2018-03-21 at 09:58 -0700, Stephen Boyd wrote:
> From: Stephen Boyd <sboyd@...eaurora.org>
> 
> Some qcom platforms make some GPIOs or pins unavailable for use by
> non-secure operating systems, and thus reading or writing the
> registers
> for those pins will cause access control issues. Add support for a DT
> property to describe the set of GPIOs that are available for use so
> that
> higher level OSes are able to know what pins to avoid reading/writing.
> Non-DT platforms can add support by directly updating the
> chip->valid_mask.

> Signed-off-by: Stephen Boyd <sboyd@...eaurora.org>
> Signed-off-by: Stephen Boyd <swboyd@...omium.org>

Hmm...

> +	gpiochip->valid_mask = kcalloc(BITS_TO_LONGS(gpiochip-
> >ngpio),
> +				       sizeof(long), GFP_KERNEL);

Just noticed that kcalloc is superfluous here.
kmalloc_array() would be enough.

> +	if (!gpiochip->valid_mask)
> +		return -ENOMEM;
> +
> +	/* Assume by default all GPIOs are valid */
> +	bitmap_fill(gpiochip->valid_mask, gpiochip->ngpio);


-- 
Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Intel Finland Oy