Hello, On Thu Feb 29, 2024 at 12:22 PM CET, Andy Shevchenko wrote: > On Wed, Feb 28, 2024 at 06:04:47PM +0100, Théo Lebrun wrote: > > On Tue Feb 27, 2024 at 6:27 PM CET, Andy Shevchenko wrote: > > > On Tue, Feb 27, 2024 at 03:55:25PM +0100, Théo Lebrun wrote: > > ... > > > > > + u32 offset = id & GENMASK(7, 0); > > > > + u32 domain = id >> 8; > > > > > > Perhaps > > > > > > u32 offset = (id & GENMASK(7, 0)) >> 0; > > > u32 domain = (id & GENMASK(31, 8)) >> 8; > > > > > > for better understanding the split? > > > > Do the additional zero-bit-shift and GENMASK() help understanding? My > > brain needs time to parse them to then notice they do nothing and > > simplify the code in my head, back to the original version. > > In my opinion yes, as you exactly showing the split. > But. The better is to use FIELD_GET(). I'll go with the FIELD_GET() option! [...] > > > > > + priv->rcdev.of_node = np; > > > > > > It's better to use device_set_node(). > > > > I don't see how device_set_node() can help? It works on struct device > > pointers. Here priv->rcdev is a reset_controller_dev struct. There are > > no users of device_set_node() in drivers/reset/. > > No users doesn't mean it's good. The API is relatively "new" and takes > care of two things: > 1) it uses agnostic interface; > 2) it doesn't require any firmware node direct dereference. > > The 2) is most important here as allows us to refactor (firmware node) code > in the future. I think I get the point of device_set_node(). I still do not understand how it could help me fill the ->of_node field in a reset_controller_dev structure? Should I be using device_set_node() to fill the struct device pointer and the reset subsystem, by some magic, will pick this up and use it for its own of_node field? I've not seen any magic/code doing that. [...] > > > > + priv->rcdev.nr_resets += __builtin_popcount(eq5r_valid_masks[i]); > > > > > > Please, use corresponding hweightXX() API. > > > > Noted. I did not find this keyword even though I searched quite a bit > > for it. "popcount" sounds more logical to me. :-) > > Hmm... But it's fundamental, it's called Hamming weight. > https://en.wikipedia.org/wiki/Hamming_weight Makes sense now. I've always called it population count following the name of the matching instruction on x86 (and I believe other ISAs). TIL. Regards, -- Théo Lebrun, Bootlin Embedded Linux and Kernel engineering https://bootlin.com
