Stefan Wahren <stefan.wahren@xxxxxxxx> writes: > Since the BCM2835 datasheet doesn't exactly specify the set-up time for > the GPIO Pull-up/down Clock Registers there was an assumption of 150 cycles > at a clock rate of 1 MHz. During a discussion [1] in the Raspberry Pi forum > it turns out that clock rate refers to the VPU which has a rate of 250 MHz. > So we can reduce the delay to a sensible value and update the comment above. > > I tested this optimization with a Raspberry Pi B and a multimeter. > > [1] - https://www.raspberrypi.org/forums/viewtopic.php?f=72&t=163352 > > Signed-off-by: Stefan Wahren <stefan.wahren@xxxxxxxx> I've confirmed that the only clock input to the hardware module that contains the GPPUD registers is the VPU clock, and I don't see anything else over in the pads area either. Reviewed-by: Eric Anholt <eric@xxxxxxxxxx>
Attachment:
signature.asc
Description: PGP signature
