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-rw-r--r--target/linux/brcm2708/patches-4.4/0252-clk-bcm2835-add-a-round-up-ability-to-the-clock-divi.patch70
1 files changed, 70 insertions, 0 deletions
diff --git a/target/linux/brcm2708/patches-4.4/0252-clk-bcm2835-add-a-round-up-ability-to-the-clock-divi.patch b/target/linux/brcm2708/patches-4.4/0252-clk-bcm2835-add-a-round-up-ability-to-the-clock-divi.patch
new file mode 100644
index 0000000000..99bb5dbfd3
--- /dev/null
+++ b/target/linux/brcm2708/patches-4.4/0252-clk-bcm2835-add-a-round-up-ability-to-the-clock-divi.patch
@@ -0,0 +1,70 @@
+From 78c280c96a984805dfa19969e927c17ccada808f Mon Sep 17 00:00:00 2001
+From: Remi Pommarel <repk@triplefau.lt>
+Date: Sun, 6 Dec 2015 17:22:46 +0100
+Subject: [PATCH 252/304] clk: bcm2835: add a round up ability to the clock
+ divisor
+
+Make bcm2835_clock_choose_div to optionally round up the chosen MASH divisor
+so that the resulting average rate will not be higher than the requested one.
+
+Signed-off-by: Remi Pommarel <repk@triplefau.lt>
+Reviewed-by: Eric Anholt <eric@anholt.net>
+Signed-off-by: Michael Turquette <mturquette@baylibre.com>
+(cherry picked from commit 9c95b32ca09364e4687b72c4e17b78dc1c420026)
+---
+ drivers/clk/bcm/clk-bcm2835.c | 22 ++++++++++++----------
+ 1 file changed, 12 insertions(+), 10 deletions(-)
+
+--- a/drivers/clk/bcm/clk-bcm2835.c
++++ b/drivers/clk/bcm/clk-bcm2835.c
+@@ -1150,22 +1150,24 @@ static int bcm2835_clock_is_on(struct cl
+
+ static u32 bcm2835_clock_choose_div(struct clk_hw *hw,
+ unsigned long rate,
+- unsigned long parent_rate)
++ unsigned long parent_rate,
++ bool round_up)
+ {
+ struct bcm2835_clock *clock = bcm2835_clock_from_hw(hw);
+ const struct bcm2835_clock_data *data = clock->data;
+- u32 unused_frac_mask = GENMASK(CM_DIV_FRAC_BITS - data->frac_bits, 0);
++ u32 unused_frac_mask =
++ GENMASK(CM_DIV_FRAC_BITS - data->frac_bits, 0) >> 1;
+ u64 temp = (u64)parent_rate << CM_DIV_FRAC_BITS;
++ u64 rem;
+ u32 div;
+
+- do_div(temp, rate);
++ rem = do_div(temp, rate);
+ div = temp;
+
+- /* Round and mask off the unused bits */
+- if (unused_frac_mask != 0) {
+- div += unused_frac_mask >> 1;
+- div &= ~unused_frac_mask;
+- }
++ /* Round up and mask off the unused bits */
++ if (round_up && ((div & unused_frac_mask) != 0 || rem != 0))
++ div += unused_frac_mask + 1;
++ div &= ~unused_frac_mask;
+
+ /* Clamp to the limits. */
+ div = max(div, unused_frac_mask + 1);
+@@ -1204,7 +1206,7 @@ static long bcm2835_clock_round_rate(str
+ unsigned long *parent_rate)
+ {
+ struct bcm2835_clock *clock = bcm2835_clock_from_hw(hw);
+- u32 div = bcm2835_clock_choose_div(hw, rate, *parent_rate);
++ u32 div = bcm2835_clock_choose_div(hw, rate, *parent_rate, false);
+
+ return bcm2835_clock_rate_from_divisor(clock, *parent_rate, div);
+ }
+@@ -1273,7 +1275,7 @@ static int bcm2835_clock_set_rate(struct
+ struct bcm2835_clock *clock = bcm2835_clock_from_hw(hw);
+ struct bcm2835_cprman *cprman = clock->cprman;
+ const struct bcm2835_clock_data *data = clock->data;
+- u32 div = bcm2835_clock_choose_div(hw, rate, parent_rate);
++ u32 div = bcm2835_clock_choose_div(hw, rate, parent_rate, false);
+
+ cprman_write(cprman, data->div_reg, div);
+