Hi! On Wed, Feb 26, 2020 at 1:31 AM Rob Herring <robh@xxxxxxxxxx> wrote: > > On Thu, Feb 20, 2020 at 07:58:06AM +0800, Chuanhong Guo wrote: > > Hi! > > > > On Tue, Feb 18, 2020 at 8:55 PM Mark Brown <broonie@xxxxxxxxxx> wrote: > > > This is an ABI break so you shouldn't be doing this, if the existing > > > binding works it should continue to work. > > > > The missing spi-max-frequency is the only part preventing old > > device tree to work with this driver. > > If the goal is to make existing dt binding work, I could patch dt using > > of_add_property in v2. I saw similar device tree patching for legacy > > bindings in pinctrl-single driver. I just noticed that of_add_property isn't a exported symbol, which means that device tree patching isn't possible unless driver is builtin. > > You should should really only need 'spi-max-frequency' if the max freq > is less than the minimum of the host and device max freq. But current spi framework forces that a "spi-max-frequency" property is present. [0] Should we patch spi framework then? [0] https://elixir.bootlin.com/linux/latest/source/drivers/spi/spi.c#L1951 -- Regards, Chuanhong Guo
