From 1c924fc679123e6057239693d226c8d8c5780626 Mon Sep 17 00:00:00 2001 From: Geert Uytterhoeven Date: Thu, 1 Apr 2021 15:01:37 +0200 Subject: [PATCH] clk: renesas: div6: Consider all parents for requested rate Currently the .determine_rate() callback considers only the current parent clock, limiting the range of achievable clock rates on DIV6 clocks with multiple parents, as found on SH/R-Mobile SoCs. Extend the callback to consider all available parent clocks. Signed-off-by: Geert Uytterhoeven Link: https://lore.kernel.org/r/60e639692b462f99e0b6ab868c3675b3d97dbdb0.1617281699.git.geert+renesas@glider.be --- drivers/clk/renesas/clk-div6.c | 35 ++++++++++++++++++++++++++++++++--- 1 file changed, 32 insertions(+), 3 deletions(-) diff --git a/drivers/clk/renesas/clk-div6.c b/drivers/clk/renesas/clk-div6.c index 3af65ef..a9ac2a8 100644 --- a/drivers/clk/renesas/clk-div6.c +++ b/drivers/clk/renesas/clk-div6.c @@ -103,10 +103,39 @@ static unsigned int cpg_div6_clock_calc_div(unsigned long rate, static int cpg_div6_clock_determine_rate(struct clk_hw *hw, struct clk_rate_request *req) { - unsigned int div = cpg_div6_clock_calc_div(req->rate, - req->best_parent_rate); + unsigned long prate, calc_rate, diff, best_rate, best_prate; + unsigned int num_parents = clk_hw_get_num_parents(hw); + struct clk_hw *parent, *best_parent = NULL; + unsigned long min_diff = ULONG_MAX; + unsigned int i, div; + + for (i = 0; i < num_parents; i++) { + parent = clk_hw_get_parent_by_index(hw, i); + if (!parent) + continue; + + prate = clk_hw_get_rate(parent); + if (!prate) + continue; + + div = cpg_div6_clock_calc_div(req->rate, prate); + calc_rate = prate / div; + diff = calc_rate > req->rate ? calc_rate - req->rate + : req->rate - calc_rate; + if (diff < min_diff) { + best_rate = calc_rate; + best_parent = parent; + best_prate = prate; + min_diff = diff; + } + } + + if (!best_parent) + return -EINVAL; - req->rate = req->best_parent_rate / div; + req->best_parent_rate = best_prate; + req->best_parent_hw = best_parent; + req->rate = best_rate; return 0; } -- 2.7.4