> clk_prepare_enable and clk_disable_unprepare check the input > clock parameter in the beginning of the function, These functions call further functions which perform null pointer checks. > if the parameter > is NULL, clk_prepare_enable and clk_disable_unprepare will > return immediately. The interpretation of these function implementations seems to be reasonable. Would you like to achieve any improvements for the corresponding software documentation? > So Don't need to check input clock parameters before calling clk API. What do you find imperative in this wording? Another wording alternative: Thus omit extra null pointer checks before four function calls. Regards, Markus