On Wed, Jul 27, 2022 at 7:21 PM Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx> wrote: > > On 27.07.2022 17:55:10, Dario Binacchi wrote: > > Hello Marc, > > > > On Wed, Jul 27, 2022 at 1:31 PM Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx> wrote: > > > > > > On 26.07.2022 23:02:16, Dario Binacchi wrote: > > > > It allows to set the bit time register with tunable values. > > > > The setting can only be changed if the interface is down: > > > > > > > > ip link set dev can0 down > > > > ethtool --set-tunable can0 can-btr 0x31c > > > > ip link set dev can0 up > > > > > > As far as I understand, setting the btr is an alternative way to set the > > > bitrate, right? > > > > I thought of a non-standard bitrate or, in addition to the bitrate, the > > possibility of enabling some specific CAN controller options. Maybe Oliver > > could help us come up with the right answer. > > > > This is the the slcan source code: > > https://github.com/linux-can/can-utils/blob/cad1cecf1ca19277b5f5db39f8ef6f8ae426191d/slcand.c#L331 > > btr case cames after speed but they don't seem to be considered alternative. > > > > > I don't like the idea of poking arbitrary values into a > > > hardware from user space. > > > > However this is already possible through the slcand and slcan_attach > > applications. > > Furthermore, the driver implements the LAWICEL ASCII protocol for CAN > > frame transport over serial lines, > > and this is one of the supported commands. > > > > > > > > Do you have a use case for this? > > > > I use the applications slcand and slcan_attach as a reference, I try to make the > > driver independent from them for what concerns the CAN setup. And the bit time > > register setting is the last dependency. > > Ok - We avoided writing bit timing registers from user space into the > hardware for all existing drivers. If there isn't a specific use case, > let's skip this patch. If someone comes up with a use case we can think > of a proper solution. Ok. So do I also remove the 7/9 "ethtool: add support to get/set CAN bit time register" patch ? Thanks and regards, Dario > > Marc > > -- > Pengutronix e.K. | Marc Kleine-Budde | > Embedded Linux | https://www.pengutronix.de | > Vertretung West/Dortmund | Phone: +49-231-2826-924 | > Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 | -- Dario Binacchi Embedded Linux Developer dario.binacchi@xxxxxxxxxxxxxxxxxxxx __________________________________ Amarula Solutions SRL Via Le Canevare 30, 31100 Treviso, Veneto, IT T. +39 042 243 5310 info@xxxxxxxxxxxxxxxxxxxx www.amarulasolutions.com