Dear Hector Palacios,
> Adds in_voltageX_scale_available file for every channel to read
> the different available scales.
> There are two scales per channel:
> [0] = divider_by_two disabled (default)
> [1] = divider_by_two enabled
> The scale is a struct made of integer and nano parts to build
> a long decimal number.
>
> Signed-off-by: Hector Palacios <hector.palac...@digi.com>
> ---
[...]
> @@ -1008,6 +1098,26 @@ static int mxs_lradc_probe(struct platform_device
> *pdev) if (ret)
> goto err_trig;
>
> + /* Populate available ADC input ranges */
> + for (i = 0; i < LRADC_MAX_TOTAL_CHANS; i++) {
> + for (s = 0; s < ARRAY_SIZE(lradc->scale_avail[i]); s++) {
> + /*
> + * [s=0] = optional divider by two disabled (default)
> + * [s=1] = optional divider by two enabled
> + *
> + * The scale is calculated by doing:
> + * Vref >> (realbits - s)
> + * which multiplies by two on the second component
> + * of the array.
> + */
> + scale_uv = ((u64)lradc->vref_mv[i] * 100000000) >>
> + (iio->channels[i].scan_type.realbits - s);
Thinking about this, this is basically
vref_mv[CHANNEL] * 100 000 000
scale_uv = --------------------------------
2^(12 - s)
Where s can be either 0 or 1.
Why do you multiply it by 100000000 I don't quite understand, but maybe it's
fully obvious. It should be documented though.
> + lradc->scale_avail[i][s].nano =
> + do_div(scale_uv, 100000000) * 10;
Are we not loosing precission here?
> + lradc->scale_avail[i][s].integer = scale_uv;
> + }
> + }
> +
> /* Configure the hardware. */
> mxs_lradc_hw_init(lradc);
Best regards,
Marek Vasut
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