kernel@xxxxxxxxxxxxxxxx writes: > From: Martin Sperl <kernel@xxxxxxxxxxxxxxxx> > > The bcm2835 SOC contains an auxiliary uart, which is very close > to the ns16550 with some differences. > > The big difference is that the uart HW is not using an internal divider > of 16 but 8, which results in an effictive baud-rate being twice > the requested baud-rate. > > The bcm2835-aux-uart is also special in such that it is enabled/disabled > by a gate in the clock, which is managed by the clk-bcm2835-aux > clock driver. > > there are 2 options: > * defining the clock-frequency property in the device tree to 500k > instead of 250k, but this keeps the HW block disabled making the > uart not work. > * defining a clock in the device tree, but this results in a baud rate > that is twice the requested baud-rate. > > To address this this patch-set introduce a new property in the device tree > to define a clock divider other than 16. > > This currently just scales the clock by a factor of 16/divider. > > Note that the use of fixed-factor-clock has also been proposed as a > workarround, but this does not really describe the hw in the device tree > so another solution was needed that allows a correct representation of > the HW in the device tree. I personally lean toward the fixed-factor-clock solution, but could go either way. Serial maintainers, what do you think?
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