[PATCH] mt9p031: Do not use PLL if external frequency is the same as target frequency.

[Javier Martin]

This patch adds a check to see whether ext_freq and target_freq are equal and,
if true, PLL won't be used.

Signed-off-by: Javier Martin <javier.mar...@vista-silicon.com>
---
 drivers/media/video/mt9p031.c |   18 +++++++++++++++---
 1 files changed, 15 insertions(+), 3 deletions(-)

diff --git a/drivers/media/video/mt9p031.c b/drivers/media/video/mt9p031.c
index 5cfa39f..42b5d18 100644
--- a/drivers/media/video/mt9p031.c
+++ b/drivers/media/video/mt9p031.c
@@ -117,6 +117,7 @@ struct mt9p031 {
        u16 xskip;
        u16 yskip;
 
+       bool use_pll;
        const struct mt9p031_pll_divs *pll;
 
        /* Registers cache */
@@ -201,10 +202,16 @@ static int mt9p031_pll_get_divs(struct mt9p031 *mt9p031)
        struct i2c_client *client = v4l2_get_subdevdata(&mt9p031->subdev);
        int i;
 
+       if (mt9p031->pdata->ext_freq == mt9p031->pdata->target_freq) {
+               mt9p031->use_pll = false;
+               return 0;
+       }
+
        for (i = 0; i < ARRAY_SIZE(mt9p031_divs); i++) {
                if (mt9p031_divs[i].ext_freq == mt9p031->pdata->ext_freq &&
                  mt9p031_divs[i].target_freq == mt9p031->pdata->target_freq) {
                        mt9p031->pll = &mt9p031_divs[i];
+                       mt9p031->use_pll = true;
                        return 0;
                }
        }
@@ -385,8 +392,10 @@ static int mt9p031_s_stream(struct v4l2_subdev *subdev, 
int enable)
                                                 MT9P031_OUTPUT_CONTROL_CEN, 0);
                if (ret < 0)
                        return ret;
-
-               return mt9p031_pll_disable(mt9p031);
+               if (mt9p031->use_pll)
+                       return mt9p031_pll_disable(mt9p031);
+               else
+                       return 0;
        }
 
        ret = mt9p031_set_params(mt9p031);
@@ -399,7 +408,10 @@ static int mt9p031_s_stream(struct v4l2_subdev *subdev, 
int enable)
        if (ret < 0)
                return ret;
 
-       return mt9p031_pll_enable(mt9p031);
+       if (mt9p031->use_pll)
+               return mt9p031_pll_enable(mt9p031);
+       else
+               return 0;
 }
 
 static int mt9p031_enum_mbus_code(struct v4l2_subdev *subdev,
-- 
1.7.0.4

--
To unsubscribe from this list: send the line "unsubscribe linux-media" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html