On Tue, Nov 12, 2019 at 01:15:26PM -0800, Drew Fustini wrote: > On Tue, Nov 12, 2019 at 1:01 PM Drew Fustini <pdp7pdp7@xxxxxxxxx> wrote: > > I based the overlay I was using one a MCP2515 overlay for SPI0 on > > BeagleBone Black: > > https://github.com/battlesnake/beaglebone-spi0-mcp2515/blob/master/MCP2515.dts > > > > I'm not sure where those extra "mcp251x," properties come from since > > the driver does not appear to use them at all. > > I searched for "mcp251x,oscillator-frequency" on google and found this > old patch by Alessandro Zummo <a.zummo@xxxxxxxxxxxx>: > https://github.com/beagleboard/meta-beagleboard/blob/master/common-bsp/recipes-kernel/linux/linux-mainline-3.8/net/0006-mcp251x-add-device-tree-support.patch > > It does read some of those properties: > + of_property_read_u32(np, "mcp251x,oscillator-frequency", &tmp); > + pd->stay_awake = of_property_read_bool(np, "mcp251x,stay-awake"); > + pd->enable_clkout = of_property_read_bool(np, "mcp251x,enable-clkout"); > Maybe there are people using this out of tree patch still and > therefore including those properties like Mark K Cowan did in: > https://github.com/beagleboard/bb.org-overlays/blob/master/src/arm/MCP2515-SPI0.dts First of all, there are rules (which are getting stricter all the time) about property names and use in DT. Second, no one cares about out-of-tree customizations. In kernel we consider no regression made if we introduce properties that are not compatible with no-one-knows DTSes (it didn't work with older kernel, it continue not working with new — status quo). -- With Best Regards, Andy Shevchenko
