From: Leo Ruan <tingquan.ruan@xxxxxxxxxxxx>
This commit corrects the printing of the IPU clock error percentage if
it is between -0.1% to -0.9%. For example, if the pixel clock requested
is 27.2 MHz but only 27.0 MHz can be achieved the deviation is -0.8%.
But the fixed point math had a flaw and calculated error of 0.2%.
Before:
Clocks: IPU 270000000Hz DI 24716667Hz Needed 27200000Hz
IPU clock can give 27000000 with divider 10, error 0.2%
Want 27200000Hz IPU 270000000Hz DI 24716667Hz using IPU, 27000000Hz
After:
Clocks: IPU 270000000Hz DI 24716667Hz Needed 27200000Hz
IPU clock can give 27000000 with divider 10, error -0.8%
Want 27200000Hz IPU 270000000Hz DI 24716667Hz using IPU, 27000000Hz
Signed-off-by: Leo Ruan <tingquan.ruan@xxxxxxxxxxxx>
Signed-off-by: Mark Jonas <mark.jonas@xxxxxxxxxxxx>
---
drivers/gpu/ipu-v3/ipu-di.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/ipu-v3/ipu-di.c b/drivers/gpu/ipu-v3/ipu-di.c
index b4a31d506fcc..74eca68891ad 100644
--- a/drivers/gpu/ipu-v3/ipu-di.c
+++ b/drivers/gpu/ipu-v3/ipu-di.c
@@ -451,8 +451,9 @@ static void ipu_di_config_clock(struct ipu_di *di,
error = rate / (sig->mode.pixelclock / 1000);
- dev_dbg(di->ipu->dev, " IPU clock can give %lu with divider %u, error %d.%u%%\n",
- rate, div, (signed)(error - 1000) / 10, error % 10);
+ dev_dbg(di->ipu->dev, " IPU clock can give %lu with divider %u, error %c%d.%d%%\n",
+ rate, div, error < 1000 ? '-' : '+',
+ abs(error - 1000) / 10, abs(error - 1000) % 10);
/* Allow a 1% error */
if (error < 1010 && error >= 990) {
--
2.17.1
