[PATCH AUTOSEL 4.18 019/131] clk: scmi: Fix the rounding of clock rate

From: Sasha Levin
Date: Sun Sep 02 2018 - 09:35:46 EST


From: Amit Daniel Kachhap <amit.kachhap@xxxxxxx>

[ Upstream commit 7a8655e19bdb3be43f6a3b4768c9b0928a2585fc ]

This fix rounds the clock rate properly by using quotient and not
remainder in the calculation. This issue was found while testing HDMI
in the Juno platform.

Fixes: 6d6a1d82eaef7 ("clk: add support for clocks provided by SCMI")
Acked-by: Sudeep Holla <sudeep.holla@xxxxxxx>
Signed-off-by: Amit Daniel Kachhap <amit.kachhap@xxxxxxx>
Signed-off-by: Stephen Boyd <sboyd@xxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx>
---
drivers/clk/clk-scmi.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/clk/clk-scmi.c b/drivers/clk/clk-scmi.c
index bb2a6f2f5516..a985bf5e1ac6 100644
--- a/drivers/clk/clk-scmi.c
+++ b/drivers/clk/clk-scmi.c
@@ -38,7 +38,6 @@ static unsigned long scmi_clk_recalc_rate(struct clk_hw *hw,
static long scmi_clk_round_rate(struct clk_hw *hw, unsigned long rate,
unsigned long *parent_rate)
{
- int step;
u64 fmin, fmax, ftmp;
struct scmi_clk *clk = to_scmi_clk(hw);

@@ -60,9 +59,9 @@ static long scmi_clk_round_rate(struct clk_hw *hw, unsigned long rate,

ftmp = rate - fmin;
ftmp += clk->info->range.step_size - 1; /* to round up */
- step = do_div(ftmp, clk->info->range.step_size);
+ do_div(ftmp, clk->info->range.step_size);

- return step * clk->info->range.step_size + fmin;
+ return ftmp * clk->info->range.step_size + fmin;
}

static int scmi_clk_set_rate(struct clk_hw *hw, unsigned long rate,
--
2.17.1