Re: [PATCH 4/5] input: tc3589x-keypad: support probing from device tree

[Mark Rutland <mark.rutland@arm.com>]

On Tue, Oct 15, 2013 at 10:21:11PM +0100, Linus Walleij wrote:
> Implement device tree probing for the tc3589x keypad driver.
> This is modeled on the STMPE keypad driver and tested on the
> Ux500 TVK1281618 UIB.
> 
> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
> ---
>  drivers/input/keyboard/tc3589x-keypad.c | 63 +++++++++++++++++++++++++++++++--
>  1 file changed, 61 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/input/keyboard/tc3589x-keypad.c b/drivers/input/keyboard/tc3589x-keypad.c
> index 208de7c..f6ec0d7 100644
> --- a/drivers/input/keyboard/tc3589x-keypad.c
> +++ b/drivers/input/keyboard/tc3589x-keypad.c
> @@ -297,6 +297,62 @@ static void tc3589x_keypad_close(struct input_dev *input)
>  	tc3589x_keypad_disable(keypad);
>  }
>  
> +#ifdef CONFIG_OF
> +static const struct tc3589x_keypad_platform_data *
> +tc3589x_keypad_of_probe(struct device *dev)
> +{
> +	struct device_node *np = dev->of_node;
> +	struct tc3589x_keypad_platform_data *plat;
> +	u32 debounce_ms;
> +	int proplen;
> +
> +	if (!np)
> +		return ERR_PTR(-ENODEV);
> +
> +	plat = devm_kzalloc(dev, sizeof(*plat), GFP_KERNEL);
> +	if (!plat)
> +		return ERR_PTR(-ENOMEM);
> +
> +	of_property_read_u8(np, "keypad,num-columns", &plat->kcol);
> +	of_property_read_u8(np, "keypad,num-rows", &plat->krow);

These look wrong to me, as almost every single use of of_property_read_u8 (or
of_property_read_u16) do. They read _packed_ values out of the dt, and do not
read (u32) cells as u8s or u16s.

The matrix-keymap binding doesn't define these as 8-bit, and the example
binding they are u32 cells. Either the binding document or this code is wrong.

I'm confused as to how this can work. Are you using /bits/ 8 in your dts?

Thanks,
Mark.