Staging: s5k3e2fx.c: simplify complexity by factoring

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@gawab.com>
Reviewed-by: Ray Lee<ray-lk@madrabbit.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/staging/dream/camera/s5k3e2fx.c b/drivers/staging/dream/camera/s5k3e2fx.c
index edba19889b0fb449a02aafd9acdfe434417d49c3..66582af5a586342ff5e7f5ff2e769a5afe9aff25 100644 (file)
--- 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++) {