Hi Mac, Fabio, > -----Original Message----- > From: Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx> > Sent: 2021年7月15日 20:15 > To: Fabio Estevam <festevam@xxxxxxxxx> > Cc: Joakim Zhang <qiangqing.zhang@xxxxxxx>; Rob Herring > <robh+dt@xxxxxxxxxx>; Shawn Guo <shawnguo@xxxxxxxxxx>; Sascha Hauer > <s.hauer@xxxxxxxxxxxxxx>; Sascha Hauer <kernel@xxxxxxxxxxxxxx>; > dl-linux-imx <linux-imx@xxxxxxx>; open list:OPEN FIRMWARE AND FLATTENED > DEVICE TREE BINDINGS <devicetree@xxxxxxxxxxxxxxx>; Aisheng Dong > <aisheng.dong@xxxxxxx> > Subject: Re: [PATCH] arm64: dts: imx8mp: remove fallback compatible string > for FlexCAN > > On 15.07.2021 09:03:55, Fabio Estevam wrote: > > Hi Joakim, > > > > On Thu, Jul 15, 2021 at 8:49 AM Joakim Zhang <qiangqing.zhang@xxxxxxx> > wrote: > > > > > > FlexCAN on i.MX8MP is not derived from i.MX6Q, instead resues from > > > i.MX8QM with extra ECC added. With "fsl,imx6q-flexcan" compatible > > > string, i.MX8MP FlexCAN would not work, so remove this fallback > compatible string. > > > > I agree with the removal of "fsl,imx6q-flexcan", but I don't > > understand your comment saying that: > > > > "With "fsl,imx6q-flexcan" compatible string, i.MX8MP FlexCAN would not > work" > > > > Why? > > Don't remember exactly why It doesn't work. I think it was a missing quirk that > the imx6 doesn't need. I could explain more if I remember correctly, i.MX8MP with ECC added and default is enabled, without FLEXCAN_QUIRK_DISABLE_MECR quirk, FlexCAN doesn't work, it will put device in freeze mode. However, as Mac described, i.MX6Q doesn't need it. > > "fsl,imx8mp-flexcan" is passed as the more specific compatible string > > and it should match against it first. > > ACK - but why specify the imx6 in the compatible list if the flexcan IP core isn't > compatible with the one of the imx6? Best Regards, Joakim Zhang > regards, > 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 |
