Updating and Modernizing Clk (Clock) Drivers - Chen-Yu Tsai, Google

Updating and Modernizing Clk (Clock) Drivers - Chen-Yu Tsai, Google
The Common Clock Framework (CCF) has grown much since its inception from the Clock API. However, clock drivers tend to not get many updates after they are merged, so it's no mystery that many have been stuck with old APIs and design patterns. Modern clock drivers should be proper platform drivers, unless early clock initialization for timers is required. They should utilize the "struct clk_hw" based clock provider API, which gives proper separation between provider and consumer APIs, and provides facilities to reference clocks through pointers instead of global clock names. And they should have proper resource management and error handling, even though a failed clock driver likely means the system is unusable. This is an account of modernizing one such collection of drivers.