diff options
Diffstat (limited to 'target/linux/brcm2708/patches-4.4/0252-clk-bcm2835-add-a-round-up-ability-to-the-clock-divi.patch')
| -rw-r--r-- | target/linux/brcm2708/patches-4.4/0252-clk-bcm2835-add-a-round-up-ability-to-the-clock-divi.patch | 70 |
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); + |