linux-kernel - Re: [PATCH v3 3/3] pinctrl: qcom: Don't allow protected pins to be requested

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Message-ID: <1521655629.23017.84.camel@linux.intel.com>
Date:   Wed, 21 Mar 2018 20:07:09 +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 3/3] pinctrl: qcom: Don't allow protected pins to be
 requested

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 and
> reset the device. With a DT/ACPI property to describe the set of
> pins that are available for use, parse the available pins and set
> the irq valid bits for gpiolib to know what to consider 'valid'.
> This should avoid any issues with gpiolib. Furthermore, implement
> the pinmux_ops::request function so that pinmux can also make
> sure to not use pins that are unavailable.
> 
> Signed-off-by: Stephen Boyd <sboyd@...eaurora.org>
> Signed-off-by: Stephen Boyd <swboyd@...omium.org>

Hmm...

> +static int msm_pinmux_request(struct pinctrl_dev *pctldev, unsigned
> offset)
> +{
> +	struct msm_pinctrl *pctrl = pinctrl_dev_get_drvdata(pctldev);
> +	struct gpio_chip *chip = &pctrl->chip;
> +
> +	if (gpiochip_line_is_valid(chip, offset))
> +		return 0;
> +
> +	return -EINVAL;

Perhaps traditional pattern

if (!...)
 return -EINVAL;

return 0;

?

> +}

>  	seq_printf(s, " %dmA", msm_regval_to_drive(drive));
> -	seq_printf(s, " %s", pulls[pull]);
> +	seq_printf(s, " %s\n", pulls[pull]);

I had commented this once, but you ignored by some reason.

I would rather just move 
 seq_puts(s, "\n");
here.

The rationale behind, besides making diff more neat, is to reduce
possible burden in the future if someone would like to squeeze more data
in between.

> +		tmp = kmalloc_array(len, sizeof(tmp[0]), GFP_KERNEL);

sizeof(*tmp) ?

> +		if (!tmp)
> +			return -ENOMEM;

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