On Mon, 15 Jul 2024, at 11:38 AM, Andre Przywara wrote:
On Sun, 14 Jul 2024 20:20:44 +1200 "Ryan Walklin" ryan@testtoast.com wrote:
Hi Ryan,
I consider the fact that the AXP209 and the AXP717 use the same I2C address a sheer coincidence, so would like to keep the code readable and maintainable. This "IS_ENABLED(AXPyyy) return AXPyyy_I2C_ADDR" patterns seems to be easy to understand and copy, IMHO. If you are concerned about generated code size: this whole function is optimised away, and is replaced with a single "mov w0, #0x34" assembly instruction, just before the respective i2c function calls. This is due to the fact that those "if" statements have compile-time constant input, so the compiler knows the final result already, and just replaces the function call with this constant load. That's a neat feature of IS_ENABLED(), and a pattern we are exercising in U-Boot for years, to keep the code both readable, but also minimal.
I did wonder if the compiler might optimise this down to a single instruction, makes perfect sense in that case and agree regarding code clarity.
In that case, and having also checked the DCDC voltage defaults are reasonable for known AXP717-integrating devices in the updated Kconfig:
Reviewed-by: Ryan Walklin ryan@testtoast.com
Regards,
Ryan