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Message-ID: <CACRpkdZbr9CvCWx_a2Cf1MiJE_FDLQM4qipqRbnTRw+jM8U7gA@mail.gmail.com>
Date: Fri, 27 Apr 2012 12:52:19 +0200
From: Linus Walleij <linus.walleij@...aro.org>
To: Dmitry Eremin-Solenikov <dbaryshkov@...il.com>
Cc: Grant Likely <grant.likely@...retlab.ca>,
Linus Walleij <linus.walleij@...ricsson.com>,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH] gpio: add a driver for GPIO pins found on AMD-8111 south
bridge chips
On Fri, Apr 27, 2012 at 12:08 PM, Dmitry Eremin-Solenikov
<dbaryshkov@...il.com> wrote:
> Add a driver to use GPIO pins available on several AMD south bridges
> (currently only AMD 8111 is supported).
>
> Signed-off-by: Dmitry Eremin-Solenikov <dbaryshkov@...il.com>
Mainly nitpicks, it's looking good overall...
> + spin_lock_irqsave(&agp->lock, flags);
> + temp = ioread8(agp->pm - PMBASE_OFFSET + PMBASE_GPIO(offset));
> + temp = (temp & 0x1c) | (!!value);
This is a bit idomatic but I think I understand what's going on. However this
0x1C magic could be better of with some #define AMD_8111_GPIO_FOO don't
you think?
> +static int amd_gpio_get(struct gpio_chip *chip, unsigned offset)
> +{
> + struct amd_gpio *agp = to_agp(chip);
> + u8 temp;
> +
> + temp = ioread8(agp->pm - PMBASE_OFFSET + PMBASE_GPIO(offset));
> +
> + dev_dbg(&agp->pdev->dev, "Getting gpio %d, reg=%02x\n", offset, temp);
> +
> + return !!(temp & 0x20);
And this could be #define AMD_8111_GPIO_INVAL or so (I bet this bit has a
name in the datasheet, right?)
> +static int amd_gpio_dirout(struct gpio_chip *chip, unsigned offset, int value)
> +{
> + struct amd_gpio *agp = to_agp(chip);
> + u8 temp;
> + unsigned long flags;
> +
> + spin_lock_irqsave(&agp->lock, flags);
> + temp = ioread8(agp->pm - PMBASE_OFFSET + PMBASE_GPIO(offset));
> + temp = (temp & 0x10) | 0x4 | (!!value);
And so on...
> + iowrite8(temp, agp->pm - PMBASE_OFFSET + PMBASE_GPIO(offset));
> + spin_unlock_irqrestore(&agp->lock, flags);
> +
> + dev_dbg(&agp->pdev->dev, "Dirout gpio %d, value %d, reg=%02x\n", offset, !!value, temp);
> +
> + return 0;
> +}
> +static int __init mod_init(void)
amd_gpio_init() maybe? These names are nice for e.g. ftrace.
> + printk(KERN_INFO "AMD-8111 GPIO detected\n");
pr_info() & friends are nice shorthands for this.
> +static void __exit mod_exit(void)
amd_gpio_mod_exit()?
> +MODULE_AUTHOR("The Linux Kernel team");
Don't be shy, put in your own name :-)
Yours,
Linus Walleij
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