4.9-stable review patch. If anyone has any objections, please let me know.
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From: Paul Cercueil paul@crapouillou.net
commit bc5d922c93491878c44c9216e9d227c7eeb81d7f upstream.
Take a parent rate of 180 MHz, and a requested rate of 4.285715 MHz. This results in a theorical divider of 41.999993 which is then rounded up to 42. The .round_rate function would then return (180 MHz / 42) as the clock, rounded down, so 4.285714 MHz.
Calling clk_set_rate on 4.285714 MHz would round the rate again, and give a theorical divider of 42,0000028, now rounded up to 43, and the rate returned would be (180 MHz / 43) which is 4.186046 MHz, aka. not what we requested.
Fix this by rounding up the divisions.
Signed-off-by: Paul Cercueil paul@crapouillou.net Tested-by: Maarten ter Huurne maarten@treewalker.org Cc: stable@vger.kernel.org Signed-off-by: Stephen Boyd sboyd@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/clk/ingenic/cgu.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-)
--- a/drivers/clk/ingenic/cgu.c +++ b/drivers/clk/ingenic/cgu.c @@ -364,16 +364,16 @@ ingenic_clk_round_rate(struct clk_hw *hw struct ingenic_clk *ingenic_clk = to_ingenic_clk(hw); struct ingenic_cgu *cgu = ingenic_clk->cgu; const struct ingenic_cgu_clk_info *clk_info; - long rate = *parent_rate; + unsigned int div = 1;
clk_info = &cgu->clock_info[ingenic_clk->idx];
if (clk_info->type & CGU_CLK_DIV) - rate /= ingenic_clk_calc_div(clk_info, *parent_rate, req_rate); + div = ingenic_clk_calc_div(clk_info, *parent_rate, req_rate); else if (clk_info->type & CGU_CLK_FIXDIV) - rate /= clk_info->fixdiv.div; + div = clk_info->fixdiv.div;
- return rate; + return DIV_ROUND_UP(*parent_rate, div); }
static int @@ -393,7 +393,7 @@ ingenic_clk_set_rate(struct clk_hw *hw,
if (clk_info->type & CGU_CLK_DIV) { div = ingenic_clk_calc_div(clk_info, parent_rate, req_rate); - rate = parent_rate / div; + rate = DIV_ROUND_UP(parent_rate, div);
if (rate != req_rate) return -EINVAL;