Clemens Koller <[EMAIL PROTECTED]> writes: > Dag-Erling Smørgrav <[EMAIL PROTECTED]> writes: > > Without knowing exacly which chip is present, there is no way for the > > userland calibration tool to know how big a difference a calibration > > step makes. > I am not talking about the calibration algorithm and it's quality.
Neither am I. > I am talking about _how_ the calibration register is addressed from > userspace. It's a simple register, some bits at address 7 and I would > expect to read/modify/write registers to do all the things you want > to do. Register access in userspace doesn't put any limitation > to applications. It requires the application to know the hardware intimately. Calibration of the M41T11 is implemented using the lower 6 bits of register 7; this is not necessarily the case for other existing or future chips. Let's say I normalize this to [-128;127]; an application that tried to speed up the clock would waste several hours increasing the calibration value from 0 to 1, 2, 3 before seeing an effect after increasing it to 4. And how do I normalize the assymetric range of the M41T11? > Having only incs and decs without getting the actual value back seems > to be an absolutely unnecessary limitation here. > You cannot get the current value back to see if it's i.e. in saturation in > a way that it doesn't make sense to inc/decrement it further or in bigger > steps > or reset it to zero... The driver will return EINVAL if you try to increment or decrement the calibration register beyond its limits. DES -- Dag-Erling Smørgrav Senior Software Developer Linpro AS - www.linpro.no - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
