On Tue, Nov 27, 2012 at 11:56:06PM +0200, Alexey Pelykh wrote: > Hello everyone, > > Original table in OMAP TRM named "UART Mode Baud Rates, Divisor > Values, and Error Rates" determines modes not for all common baud > rates. E.g. for 1000000 baud rate mode should be 16x, but according to > that table it's determined as 13x. According to current implementation > of mode > divisor selection, after requesting 1000000 baudrate from driver, > later one will configure chip to use MODE13 divisor. Assuming 48Mhz as > common UART clock speed, MODE13 divisor will effectively give 1230769 > baudrate, what is quite far from desired 1000000 baudrate. While with > MODE16 divisor, chip will produce exact 1000000 baudrate. > > In old driver that served UART devices (8250.c and serial_core.c) this > divisor could have been configured by user-space program, but in > omap_serial.c driver implementation this ability was not implemented > (afaik, by design) thus disallowing proper usage of MODE16-compatible > baudrates. > > Best regards, > Alexey Pelykh > > The following changes since commit 77b67063bb6bce6d475e910d3b886a606d0d91f7: > > Linux 3.7-rc5 (2012-11-11 13:44:33 +0100) > > are available in the git repository at: > > git://github.com/alexey-pelykh/linux.git omap_serial_mode_fix > > for you to fetch changes up to cf827bb4057fdcdaeac20b95b01c29c068109185: > > Tweak to support 1Mbaud and similar baudrates that require Mode16 > instead of Mode13 (2012-11-12 19:29:27 +0200) Sorry, I can't take a git pull request for a single patch, please just send it in an email (the patch that is), with the correct signed-off-by: information, as described in Documentation/SubmittingPatches, and I will be glad to queue it up. thanks, greg k-h -- To unsubscribe from this list: send the line "unsubscribe linux-serial" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
