diff options
author | Remi Pommarel <repk@triplefau.lt> | 2015-12-06 17:22:46 +0100 |
---|---|---|
committer | Michael Turquette <mturquette@baylibre.com> | 2015-12-24 20:38:06 -0800 |
commit | 9c95b32ca09364e4687b72c4e17b78dc1c420026 (patch) | |
tree | 2bed5fd0556a5023585d0a9c58006ba78edff4bd /drivers/clk/bcm | |
parent | 5e63dcc74b3066659ea53aeefbee1fc1d79f4b6f (diff) | |
download | linux-9c95b32ca09364e4687b72c4e17b78dc1c420026.tar.bz2 |
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>
Diffstat (limited to 'drivers/clk/bcm')
-rw-r--r-- | drivers/clk/bcm/clk-bcm2835.c | 22 |
1 files changed, 12 insertions, 10 deletions
diff --git a/drivers/clk/bcm/clk-bcm2835.c b/drivers/clk/bcm/clk-bcm2835.c index 39bf5820297e..9e881eef3c36 100644 --- a/drivers/clk/bcm/clk-bcm2835.c +++ b/drivers/clk/bcm/clk-bcm2835.c @@ -1148,22 +1148,24 @@ static int bcm2835_clock_is_on(struct clk_hw *hw) 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); @@ -1202,7 +1204,7 @@ static long bcm2835_clock_round_rate(struct clk_hw *hw, 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); } @@ -1271,7 +1273,7 @@ static int bcm2835_clock_set_rate(struct clk_hw *hw, 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); |