On 20/03/2020 15:10, Thierry Reding wrote: > On Fri, Mar 20, 2020 at 11:37:16AM +0000, Jon Hunter wrote: >> Add a custom SoC attribute for Tegra to expose the HIDREV register >> contents to userspace via the sysfs. This register provides additional >> details about the fabrication and versioning of the device. Exposing >> this information is useful for identifying the exact device revision and >> device type. >> >> Please note that the fields in this register vary depending on the Tegra >> generation and so instead of exposing the individual fields, just expose >> the entire contents of the register. Details of the register fields can >> be found in the Technical Reference Manual for each Tegra device. > > That seems a little suboptimal to me. It's pretty trivial for the kernel > to distinguish between different SoC generations in order to know what > the fields are. It's a lot more difficult for userspace to do so. Is the > register completely different between SoC generations or just slightly? It looks like only Tegra194 is different which is a shame. Unfortunately, does not appear to be documented in the public TRM at the moment. Hopefully we can fix that. > Having individual fields exposed as individual attributes seems like it > would make it a lot easier for userspace to get at the needed bits. Yes that does make sense. Jon -- nvpublic
