Hello, > Three months ago Lars-Peter revised description of device driver[1]. me, not Lars-Peter > Correctly, device's sensitivity is 0.3 uT/LSB typ and One micro tesla equal 0.01 gauss[2]. > So I have fixed calculation formula,And then add RAW_TO_GAUSS macro. > Scale are returned as VAL_INT_PLUS_MICRO. > Additionally, I have add device name. +#define RAW_TO_GAUSS(asa) ((((asa) + 128) * 3000) / 256) * * Since 1uT = 0.01 gauss, our final scale factor becomes: * - * Hadj = H * ((ASA + 128) / 256) * 3/10 * 100 - * Hadj = H * ((ASA + 128) * 30 / 256 + * Hadj = H * ((ASA + 128) / 256) * 3/10 * 1/100 + * Hadj = H * ((ASA + 128) * 0.003) / 256 * * Since ASA doesn't change, we cache the resultant scale factor into the * device context in ak8975_setup(). */ - data->raw_to_gauss[0] = ((data->asa[0] + 128) * 30) >> 8; + data->raw_to_gauss[0] = RAW_TO_GAUSS(data->asa[0]); thank you for following up on this; I don't have the hardware, so I didn't dare to change the driver... the RAW_TO_GAUSS() macro doesn't match the comment Hadj = H * ... anymore maybe put this explanation in the patch comment, not the cover letter? regards, p. -- Peter Meerwald +43-664-2444418 (mobile) -- 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
