On Mon, May 02, 2016 at 08:37:15PM +0200, Mathieu OTHACEHE wrote: > Hi Johan, > > Thanks for your review. > > > Looks like this code could use a few vid/pid temporaries. > > > I'm not sure it makes sense to try to load a "ti_usb-v110a-p1150.fw" > > firmware before requesting the moxa firmware. Avoids a confusing: > > > usb 1-2.2: Direct firmware load for ti_usb-v110a-p1150.fw failed with error -2 > > > message too. > > I'm not sure to get your point here, shall I rename moxa firmwares in > linux-firmware repo to be compliant with ti_usb-v%04x-p%04x.fw format ? No, I was trying to say that the we should not attempt to load a firmware on the "ti_usb-v%04x-p%04x.fw" format before loading the moxa firmware. I guess the moxa firmware names have been chosen by Moxa and it might be confusing if we renamed them, but that could be an option too. > > I did a quick test of the patch using a Moxa 1150-device. Works at > > 115200, but communication appeared broken at 9600. Looks like the baud > > rate calculations are similar but not identical to what the Moxa driver > > does. Is this something you have looked into? > > Well, on my moxa 1110 communication is working at 9600, 115200 and > other baud rates. I must have messed something up in my test, as now 9600 seems to work. > However, I think baud rate calculation may be wrong for TI3410 chips. > > According to table 5-13 in datasheet http://www.ti.com/lit/ds/symlink/tusb3410.pdf > the baud rate calculation formula, is : > > baud_rate = 923077 / (desired_baud_rate) > > So, we get : > > desired_baud = 9600 -> baud_rate = 923077 / 9600 = 96 > desired_baud = 115200 -> baud_rate = 923077 / 115200 = 8 > ... > > In ti_usb_3410_5052 driver, the formula used for 3410 is : > > baud_rate = (923077 + desired_baud_rate/2) / desired_baud_rate > > so, > > desired_baud = 9600 -> baud_rate = (923077 + 9600/2) / 9600 = 97 (!= 96) > desired_baud = 115200 -> baud_rate = (923077 + 115200/2) / 115200 = 9 (!= 8) > > It seems the formula is wrong but some firmware deal with it anyway. > Should I correct the formula or use a quirk for moxa devices ? No, that's just integer-division with rounding. Remember that the divisions above are integer divisions so the results are actually 96 and 8 as expected. Thanks, Johan -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
