Re: [PATCH v2 1/4] ASoC: WM8903: Expose GPIOs through gpiolib

[Stephen Warren <swarren@nvidia.com>]

Mark Brown wrote on Thursday, January 20, 2011 4:53 AM:
> 
> On Wed, Jan 19, 2011 at 01:50:02PM -0700, Stephen Warren wrote:
> 
> This looks good, one query and one minor omission though.
> 
> >  /* Used to enable configuration of a GPIO to all zeros */
> > -#define WM8903_GPIO_NO_CONFIG 0x8000
> > +#define WM8903_GPIO_NO_CONFIG 0x10000
> 
> Why this change?  The top bit in the registers is never actually used,
> really they're all 15 bit.

Some other registers appear to have bit 15 defined, so I made sure this flag
was completely outside any valid register bits.

Although mainly, I just made it consistent with wm8962.h, which I assume
picked that value for the same reason.

That said, the original value was OK for the GPIO registers, so I can revert
that if you want.

> > +static int wm8903_gpio_direction_in(struct gpio_chip *chip, unsigned offset)
> > +{
> > +	struct wm8903_priv *wm8903 = gpio_to_wm8903(chip);
> > +	struct snd_soc_codec *codec = wm8903->codec;
> > +
> > +	return snd_soc_update_bits(codec, WM8903_GPIO_CONTROL_1 + offset,
> > +				   WM8903_GP1_DIR_MASK, WM8903_GP1_DIR);
> > +}
> 
> > +static int wm8903_gpio_direction_out(struct gpio_chip *chip,
> > +				     unsigned offset, int value)
> > +{
> > +	struct wm8903_priv *wm8903 = gpio_to_wm8903(chip);
> > +	struct snd_soc_codec *codec = wm8903->codec;
> > +
> > +	return snd_soc_update_bits(codec, WM8903_GPIO_CONTROL_1 + offset,
> > +				   WM8903_GP1_DIR_MASK | WM8903_GP1_LVL_MASK,
> > +				   value << WM8903_GP2_LVL_SHIFT);
> > +}
> 
> These should also set GPn_FN - to zero for GPIO output, 3 for GPIO
> input.  Otherwise changing between input and output mode at runtime
> won't do the right thing.  As a side effect of that you probably
> wouldn't need to specify the GPIO configuration in platform data.

Ooops. I didn't notice that. How does this interact with bit 7; GPn_DIR? I
assume both need to be set appropriately since they're both defined bits.

-- 
nvpublic