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Subject[PATCH] clk: clk-divider: round divider to a valid value when a table is used
Date
clk_divider_bestdiv computes the bestdiv without taking into account if
it is a valid value when CLK_SET_RATE_PARENT is not set, and it may not
be if a table is used. round_rate then returns a rate that is not
reachable by the clock, leading to a set_rate that does nothing but
reports no error.
This patch makes round_rate return a valid rate.

Signed-off-by: Damien Riegel <damien.riegel.ext@parrot.com>
---
drivers/clk/clk-divider.c | 20 +++++++++++++++++++-
1 file changed, 19 insertions(+), 1 deletion(-)

diff --git a/drivers/clk/clk-divider.c b/drivers/clk/clk-divider.c
index 8d3009e..ab02881 100644
--- a/drivers/clk/clk-divider.c
+++ b/drivers/clk/clk-divider.c
@@ -144,6 +144,23 @@ static bool _is_valid_div(struct clk_divider *divider, unsigned int div)
return true;
}

+static int _round_to_valid_div(struct clk_divider *divider, int div)
+{
+ const struct clk_div_table *clkt = divider->table;
+ int bestdiv;
+
+ if (!clkt)
+ return div;
+
+ for (bestdiv = clkt->div; clkt->div; clkt++) {
+ if (clkt->div >= div &&
+ bestdiv - div > clkt->div - div)
+ bestdiv = clkt->div;
+ }
+
+ return bestdiv;
+}
+
static int clk_divider_bestdiv(struct clk_hw *hw, unsigned long rate,
unsigned long *best_parent_rate)
{
@@ -161,7 +178,8 @@ static int clk_divider_bestdiv(struct clk_hw *hw, unsigned long rate,
parent_rate = *best_parent_rate;
bestdiv = DIV_ROUND_UP(parent_rate, rate);
bestdiv = bestdiv == 0 ? 1 : bestdiv;
- bestdiv = bestdiv > maxdiv ? maxdiv : bestdiv;
+ bestdiv = bestdiv > maxdiv ? maxdiv :
+ _round_to_valid_div(divider, bestdiv);
return bestdiv;
}

--
1.7.10.4


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