[PATCH v4 2/6] Documentation: common clk API
Amit Kucheria
amit.kucheria at linaro.org
Thu Jan 5 09:31:05 EST 2012
Tiny, tiny typo...
On 11 Dec 13, Mike Turquette wrote:
> +clk_set_rate deserves a special mention because it is more complex than
> +the other operations. There are three key concepts to the common
> +clk_set_rate implementation:
> +
> +1) recursively traversing up the clk tree and changing clk rates, one
> +parent at a time, if each clk allows it
> +2) failing to change rate if the clk is enabled and must only change
> +rates while disabled
> +3) using clk rate change notifiers to allow devices to handle dynamic
> +rate changes for clks which do support changing rates while enabled
> +
> +For the simple, non-recursive case the call graph looks like:
> +
> +clk_set_rate(clk, rate);
> + __clk_set_rate(clk, rate);
> + clk->round_rate(clk, rate *parent_rate);
^^^^^^^^
need a comma here? The next sentence kept me busy for 5 mins.
> + clk->set_rate(clk, rate);
> +
> +You might be wondering what that third paramater in .round_rate is. If
> +a clk supports the CLK_PARENT_SET_RATE flag then that enables it's
> +hardware-specific .round_rate function to provide a new rate that the
> +parent should transition to. For example, imagine a rate-adjustable clk
> +A that is the parent of clk B, which has a fixed divider of 2.
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