On Thursday 20 October 2016 10:40 PM, Paweł Jarosz wrote:
Yes please send patch to replace the 1000 with the temp1 - temp2 as
what you did in your original patch.
This will fix the non-sequenced (un-equally spaced) temperature table.
replacing 1000 with (temp1 - temp2) is not enough as for example for
val = 9 and table
<7000 8
9000 10>
It is Negative Coefficient Thermistor (NCT) and so adc reads are different.
Lower temp gives higher value.
So table should be
<7000 10
9000 8>;
temp1 = gti->lookup_table[2 * i];
temp2 = gti->lookup_table[2 * i - 2];
and then use in following equation.
adc_hi = gti->lookup_table[2 * i - 1];
adc_lo = gti->lookup_table[2 * i + 1];
temp = gti->lookup_table[2 * i];
temp -= (val - adc_lo) * (temp1 - temp2) / (adc_hi - adc_lo);
adc_hi = 8
adc_lo = 10
temp = 9000 - (9 - 10) * (7000 - 9000) / (8 - 10)
temp = 9000 - (-1) * (-2000) / (-2)
temp = 9000 - (-1000) = 10000
and for val = 9 temp should be 8000.
-----------------------------------------------------------------------------------
This email message is for the sole use of the intended recipient(s) and may contain
confidential information. Any unauthorized review, use, disclosure or distribution
is prohibited. If you are not the intended recipient, please contact the sender by
reply email and destroy all copies of the original message.
-----------------------------------------------------------------------------------
--
To unsubscribe from this list: send the line "unsubscribe linux-iio" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
