Thanks Robert!! Would really like to test the 485 mode in the 8250 driver, but before that, we're going to try to get 485 mode enabled on the FTDI FT4232 USB<->serial hub. We've ordered some FT4232 Mini Module evaluation boards for FT4232 (FT4232H chip + EEPROM + breakout pins + mini USB port). The biggest what if at the moment is how to write to the onboard EEPROM from Linux. Thus far, https://www.acmesystems.it/CM3-HOME_ft4232_setup looks promising, as the EEPROM tools appear to be talking to our EEPROM-less FT4232H chip on our custom board. .
Plan to post up on our findings/stumbling blocks here. If we can get this working, then this MAY be of interest to those looking for a quick RS 485 solution. Regards, Jeff On Thursday, August 2, 2018 at 8:37:26 AM UTC-5, RobertCNelson wrote: > > On Thu, Aug 2, 2018 at 8:22 AM Jeff Andich <jeff....@gmail.com > <javascript:>> wrote: > > > > Hi, > > > > What's the best way to find out how long a legacy driver like the > omap-serial driver will be supported in the kernel going forward? > > It's not going anywhere till they are feature matching.. > > > > > We've swapped out the 8250 driver for the OMAP serial driver via the > .config file, since the omap serial driver implements a 485 mode which, > thus far, appears to be functioning correctly for our application. On the > next spin of our board, we plan to realize more 485 channels using the > omap-serial driver and GPIO lines. > > > > We're currently "baselined" on kernel 4.4.110, but if we need to upgrade > to a newer kernel version at some point, this could be an issue if the > OMAP-serial driver is obsoleted in a later kernel. > > > > As of yet, we haven't tested the RS485 mode which has been implemented > in the 8250 serial driver in kernel 4.6 and later, but if there are known > plans for dropping support for the omap-serial driver, then we will > definitely test the 8250/RS485 implementation. > > > > Thus far have looked at the following, and didn't SEE any plans for > obsolescence: > > > > > https://github.com/torvalds/linux/commits/master/drivers/tty/serial/omap-serial.c > > > > > Also, comments like the following lead me to believe that the > omap-serial driver will be around as long as the omap platform > > is still supported. It SOUNDS almost like the 8250 driver is generic > for other platforms (e.g. other than OMAP) which > > don't support DMA. > > > > > > * Note: This driver is made separate from 8250 driver as we cannot > > * over load 8250 driver with omap platform specific configuration for > > * features like DMA, it makes easier to implement features like DMA and > > * hardware flow control and software flow control configuration with > > * this driver as required for the omap-platform > > Yeah, that "was" pretty much the state of the 8250 driver circa 2.6.32 > > 485 mode is really the only thing the omap driver does better at this > point in today's kernel.. > > Regards, > > -- > Robert Nelson > https://rcn-ee.com/ > -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to beagleboard+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/e0a04cdd-4745-4a23-9ad8-9442df864a1a%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
