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clk: ingenic: cgu: Switch to determine_rate

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The Ingenic CGU clocks implements a mux with a set_parent hook, but
doesn't provide a determine_rate implementation.

This is a bit odd, since set_parent() is there to, as its name implies,
change the parent of a clock. However, the most likely candidate to
trigger that parent change is a call to clk_set_rate(), with
determine_rate() figuring out which parent is the best suited for a
given rate.

The other trigger would be a call to clk_set_parent(), but it's far less
used, and it doesn't look like there's any obvious user for that clock.

So, the set_parent hook is effectively unused, possibly because of an
oversight. However, it could also be an explicit decision by the
original author to avoid any reparenting but through an explicit call to
clk_set_parent().

The driver does implement round_rate() though, which means that we can
change the rate of the clock, but we will never get to change the
parent.

However, It's hard to tell whether it's been done on purpose or not.

Since we'll start mandating a determine_rate() implementation, let's
convert the round_rate() implementation to a determine_rate(), which
will also make the current behavior explicit. And if it was an
oversight, the clock behaviour can be adjusted later on.

Cc: Paul Cercueil <paul@crapouillou.net>
Cc: linux-mips@vger.kernel.org
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://lore.kernel.org/r/20221018-clk-range-checks-fixes-v4-59-971d5077e7d2@cerno.tech
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
This commit is contained in:
Maxime Ripard 2023-05-05 13:26:01 +02:00 committed by Stephen Boyd
parent 15d3f365ab
commit fa0dadde05
1 changed files with 8 additions and 7 deletions
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15
drivers/clk/ingenic/cgu.c
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@ -491,22 +491,23 @@ ingenic_clk_calc_div(struct clk_hw *hw,
return div;
}
static long
ingenic_clk_round_rate(struct clk_hw *hw, unsigned long req_rate,
unsigned long *parent_rate)
static int ingenic_clk_determine_rate(struct clk_hw *hw,
struct clk_rate_request *req)
{
struct ingenic_clk *ingenic_clk = to_ingenic_clk(hw);
const struct ingenic_cgu_clk_info *clk_info = to_clk_info(ingenic_clk);
unsigned int div = 1;
if (clk_info->type & CGU_CLK_DIV)
div = ingenic_clk_calc_div(hw, clk_info, *parent_rate, req_rate);
div = ingenic_clk_calc_div(hw, clk_info, req->best_parent_rate,
req->rate);
else if (clk_info->type & CGU_CLK_FIXDIV)
div = clk_info->fixdiv.div;
else if (clk_hw_can_set_rate_parent(hw))
*parent_rate = req_rate;
req->best_parent_rate = req->rate;
return DIV_ROUND_UP(*parent_rate, div);
req->rate = DIV_ROUND_UP(req->best_parent_rate, div);
return 0;
}
static inline int ingenic_clk_check_stable(struct ingenic_cgu *cgu,
@ -626,7 +627,7 @@ static const struct clk_ops ingenic_clk_ops = {
.set_parent = ingenic_clk_set_parent,
.recalc_rate = ingenic_clk_recalc_rate,
.round_rate = ingenic_clk_round_rate,
.determine_rate = ingenic_clk_determine_rate,
.set_rate = ingenic_clk_set_rate,
.enable = ingenic_clk_enable,