On Sun, Feb 27, 2022 at 6:44 PM Peng Fan <peng.fan@xxxxxxx> wrote: > > Hi Rob, > > > Subject: Re: [PATCH] dt-bindings: serial: fsl-lpuart: Add imx93 compatible > > string > > > > On Tue, Feb 15, 2022 at 04:13:34PM +0800, Peng Fan (OSS) wrote: > > > From: Peng Fan <peng.fan@xxxxxxx> > > > > > > The lpuart on i.MX93 is derived from i.MX8ULP with some industrial > > > enhancements, it uses three compatible strings, so update the > > > > Looks like it's 2 compatible strings... > > Oh, yes. i.MX8ULP/7ULP is same uart IP. > > > > > > compatible string for i.MX93. But for a few instants, > > > > s/instants/instances/ > > > > > DTR_B, DSR_B, DCD_B and RIN_B pins are supported, so use one > > > compatible string fsl,imx93-lpuart-v2 > > > > If the differences are just what gets pinned out, then I think the differences > > should be handled with separate properties. We probably already have some. > > > > Plus, while you may have all the above signals, a board design may still only > > use a subset. > > It is SoC integration level with above features not support in some instances, > so no such signals connected to SoC pin. > > Saying LPUART IP itself support DTR/DSR/DCD/RIN, but instance A has the > feature disabled when doing SoC integration, instance B has the feature enabled > when doing SoC integration. What's your suggestion with such case? Unless it changes the register interface in a non-compatible way that the driver needs to know about, I would not do a different compatible. For example, register offsets change. Rob
