Re: [PATCH 1/2] iio: light: adux1020: fix interrupt clear value on SMBus-only adapters

[Andy Shevchenko]

On Mon, Nov 09, 2026 at 11:39:02AM +0000, Raffaele Tranfaglia via B4 Relay wrote:
> 
> adux1020_measure() clears the mode interrupt by writing the inverted
> interrupt enable mask to INT_STATUS. The mask is a u16, but integer
> promotion makes ~0x00f0 evaluate to 0xffffff0f, which does not fit in
> the 16-bit register.

Huh?! Where did you get it from? the mentioned promotion may only happen for
a signed char which may not hold 0x00f0 in the first place. The above is some
nonsense.

> On adapters supporting plain I2C, regmap formats the value with
> put_unaligned_be16() and silently truncates it to 0xff0f. On adapters
> that only support SMBus word transfers, regmap_smbus_word_write_swapped()
> rejects values above 0xffff with -EINVAL, so every proximity read fails.
> 
> Mask the value to 16 bits so that SMBus-only adapters send the same
> 0xff0f that has always been written on plain I2C adapters.

...

>  	ret = regmap_write(data->regmap, ADUX1020_REG_INT_STATUS,
> -			   (~adux1020_modes[mode].int_en));
> +			   ~adux1020_modes[mode].int_en & 0xffff);

On top of that regmap should limit the value to 16-bit anyway. If there is a
problem in regmap to cut the upper bits, it should be addressed rather there.

>  	if (ret < 0)
>  		return ret;

-- 
With Best Regards,
Andy Shevchenko