Hi Stephen,
On Tue, Mar 07, 2017 at 06:11:57AM -0800, Stephen Boyd wrote:
On 03/07, Maxime Ripard wrote:
So far, divider_round_rate only considers the parent clock returned by clk_hw_get_parent.
This works fine on clocks that have a single parents, this doesn't work on muxes, since we will only consider the first parent, while other parents may totally be able to provide a better combination.
Clocks in that case cannot use divider_round_rate, so would have to come up with a very similar logic to work around it. Instead of having to do something like this, and duplicate that logic everywhere, give an additional parameter for the parent clock to consider.
Current users have been converted using the following coccinelle script
@@ identifier hw, rate, prate, table, width, flags; @@
-long divider_round_rate(struct clk_hw *hw, +long divider_round_rate(struct clk_hw *hw, struct clk_hw *parent, unsigned long rate, unsigned long *prate, const struct clk_div_table *table, u8 width, unsigned long flags) { ... }
@@ identifier fn, hw; expression E2, E3, E4, E5, E6; @@ fn (struct clk_hw *hw, ...) { <... -divider_round_rate(hw, E2, E3, E4, E5, E6) +divider_round_rate(hw, clk_hw_get_parent(hw), E2, E3, E4, E5, E6) ...> }
Why not introduce another function like
divider_round_rate_parent() divider_round_rate_mux()
that takes the extra parent argument? Technically, a divider is considered to only have one parent, and if it has more than one parent, then it is a mux and a divider.
Yes, that would work too, without needing the cross tree change. I'll do that in the next version.
Thanks! Maxime