From: Justin Madru <jdm64@xxxxxxxxx>
the code was looping, setting s_move[i] to the following calculations
if (actual_step>= 0)
s_move[i] = ((((i + 1) * gain + 0x200) - (i * gain + 0x200)) / 0x400);
else
s_move[i] = ((((i + 1) * gain - 0x200) - (i * gain - 0x200)) / 0x400);
but, this code reduces to the expression
s_move[i] = gain>> 10;
The reason for the complexity was to generate a step function with
integer division and rounding to land on specific values. But these calculations
can be simplified to the following code:
gain = ((actual_step<< 10) / 5)>> 10;
for (i = 0; i<= 4; i++)
s_move[i] = gain;
Signed-off-by: Justin Madru<jdm64@xxxxxxxxx>
Reviewed-by: Ray Lee<ray-lk@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>
---
drivers/staging/dream/camera/s5k3e2fx.c | 10 +++-------
1 files changed, 3 insertions(+), 7 deletions(-)
diff --git a/drivers/staging/dream/camera/s5k3e2fx.c b/drivers/staging/dream/camera/s5k3e2fx.c
index edba198..66582af 100644
--- a/drivers/staging/dream/camera/s5k3e2fx.c
+++ b/drivers/staging/dream/camera/s5k3e2fx.c
@@ -1093,14 +1093,10 @@ static int32_t s5k3e2fx_move_focus(int direction, int32_t num_steps)
actual_step = step_direction * (int16_t)num_steps;
pos_offset = init_code + s5k3e2fx_ctrl->curr_lens_pos;
- gain = actual_step * 0x400 / 5;
+ gain = ((actual_step << 10) / 5) >> 10;
- for (i = 0; i <= 4; i++) {
- if (actual_step >= 0)
- s_move[i] = ((((i+1)*gain+0x200) - (i*gain+0x200))/0x400);
- else
- s_move[i] = ((((i+1)*gain-0x200) - (i*gain-0x200))/0x400);
- }
+ for (i = 0; i <= 4; i++)
+ s_move[i] = gain;
/* Ring Damping Code */
for (i = 0; i <= 4; i++) {
--
1.7.0.1
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