[media] mt9v032: Fix binning configuration

The sensor can scale the image down using binning by 1, 2 or 4 in both
directions. Update size enumeration and ratio and binning factor
computation accordingly.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>

diff --git a/drivers/media/i2c/mt9v032.c b/drivers/media/i2c/mt9v032.c
index 12360e475739d3f7076621f5f0e0f52e692bf7a0..38bf66436c6e3b7c7a680af91eed9c28cf2fe26c 100644 (file)
--- a/drivers/media/i2c/mt9v032.c
+++ b/drivers/media/i2c/mt9v032.c
@@ -127,6 +127,8 @@ struct mt9v032 {
 
        struct v4l2_mbus_framefmt format;
        struct v4l2_rect crop;
+       unsigned int hratio;
+       unsigned int vratio;
 
        struct v4l2_ctrl_handler ctrls;
        struct {
@@ -311,22 +313,20 @@ static int mt9v032_s_stream(struct v4l2_subdev *subdev, int enable)
                       | MT9V032_CHIP_CONTROL_SEQUENTIAL;
        struct i2c_client *client = v4l2_get_subdevdata(subdev);
        struct mt9v032 *mt9v032 = to_mt9v032(subdev);
-       struct v4l2_mbus_framefmt *format = &mt9v032->format;
        struct v4l2_rect *crop = &mt9v032->crop;
-       unsigned int hratio;
-       unsigned int vratio;
+       unsigned int hbin;
+       unsigned int vbin;
        int ret;
 
        if (!enable)
                return mt9v032_set_chip_control(mt9v032, mode, 0);
 
        /* Configure the window size and row/column bin */
-       hratio = DIV_ROUND_CLOSEST(crop->width, format->width);
-       vratio = DIV_ROUND_CLOSEST(crop->height, format->height);
-
+       hbin = fls(mt9v032->hratio) - 1;
+       vbin = fls(mt9v032->vratio) - 1;
        ret = mt9v032_write(client, MT9V032_READ_MODE,
-                   (hratio - 1) << MT9V032_READ_MODE_ROW_BIN_SHIFT |
-                   (vratio - 1) << MT9V032_READ_MODE_COLUMN_BIN_SHIFT);
+                           hbin << MT9V032_READ_MODE_COLUMN_BIN_SHIFT |
+                           vbin << MT9V032_READ_MODE_ROW_BIN_SHIFT);
        if (ret < 0)
                return ret;
 
@@ -369,12 +369,12 @@ static int mt9v032_enum_frame_size(struct v4l2_subdev *subdev,
                                   struct v4l2_subdev_fh *fh,
                                   struct v4l2_subdev_frame_size_enum *fse)
 {
-       if (fse->index >= 8 || fse->code != V4L2_MBUS_FMT_SGRBG10_1X10)
+       if (fse->index >= 3 || fse->code != V4L2_MBUS_FMT_SGRBG10_1X10)
                return -EINVAL;
 
-       fse->min_width = MT9V032_WINDOW_WIDTH_DEF / fse->index;
+       fse->min_width = MT9V032_WINDOW_WIDTH_DEF / (1 << fse->index);
        fse->max_width = fse->min_width;
-       fse->min_height = MT9V032_WINDOW_HEIGHT_DEF / fse->index;
+       fse->min_height = MT9V032_WINDOW_HEIGHT_DEF / (1 << fse->index);
        fse->max_height = fse->min_height;
 
        return 0;
@@ -391,18 +391,30 @@ static int mt9v032_get_format(struct v4l2_subdev *subdev,
        return 0;
 }
 
-static void mt9v032_configure_pixel_rate(struct mt9v032 *mt9v032,
-                                        unsigned int hratio)
+static void mt9v032_configure_pixel_rate(struct mt9v032 *mt9v032)
 {
        struct i2c_client *client = v4l2_get_subdevdata(&mt9v032->subdev);
        int ret;
 
        ret = v4l2_ctrl_s_ctrl_int64(mt9v032->pixel_rate,
-                                    mt9v032->sysclk / hratio);
+                                    mt9v032->sysclk / mt9v032->hratio);
        if (ret < 0)
                dev_warn(&client->dev, "failed to set pixel rate (%d)\n", ret);
 }
 
+static unsigned int mt9v032_calc_ratio(unsigned int input, unsigned int output)
+{
+       /* Compute the power-of-two binning factor closest to the input size to
+        * output size ratio. Given that the output size is bounded by input/4
+        * and input, a generic implementation would be an ineffective luxury.
+        */
+       if (output * 3 > input * 2)
+               return 1;
+       if (output * 3 > input)
+               return 2;
+       return 4;
+}
+
 static int mt9v032_set_format(struct v4l2_subdev *subdev,
                              struct v4l2_subdev_fh *fh,
                              struct v4l2_subdev_format *format)
@@ -420,21 +432,25 @@ static int mt9v032_set_format(struct v4l2_subdev *subdev,
 
        /* Clamp the width and height to avoid dividing by zero. */
        width = clamp_t(unsigned int, ALIGN(format->format.width, 2),
-                       max(__crop->width / 8, MT9V032_WINDOW_WIDTH_MIN),
+                       max(__crop->width / 4, MT9V032_WINDOW_WIDTH_MIN),
                        __crop->width);
        height = clamp_t(unsigned int, ALIGN(format->format.height, 2),
-                        max(__crop->height / 8, MT9V032_WINDOW_HEIGHT_MIN),
+                        max(__crop->height / 4, MT9V032_WINDOW_HEIGHT_MIN),
                         __crop->height);
 
-       hratio = DIV_ROUND_CLOSEST(__crop->width, width);
-       vratio = DIV_ROUND_CLOSEST(__crop->height, height);
+       hratio = mt9v032_calc_ratio(__crop->width, width);
+       vratio = mt9v032_calc_ratio(__crop->height, height);
 
        __format = __mt9v032_get_pad_format(mt9v032, fh, format->pad,
                                            format->which);
        __format->width = __crop->width / hratio;
        __format->height = __crop->height / vratio;
-       if (format->which == V4L2_SUBDEV_FORMAT_ACTIVE)
-               mt9v032_configure_pixel_rate(mt9v032, hratio);
+
+       if (format->which == V4L2_SUBDEV_FORMAT_ACTIVE) {
+               mt9v032->hratio = hratio;
+               mt9v032->vratio = vratio;
+               mt9v032_configure_pixel_rate(mt9v032);
+       }
 
        format->format = *__format;
 
@@ -490,8 +506,11 @@ static int mt9v032_set_crop(struct v4l2_subdev *subdev,
                                                    crop->which);
                __format->width = rect.width;
                __format->height = rect.height;
-               if (crop->which == V4L2_SUBDEV_FORMAT_ACTIVE)
-                       mt9v032_configure_pixel_rate(mt9v032, 1);
+               if (crop->which == V4L2_SUBDEV_FORMAT_ACTIVE) {
+                       mt9v032->hratio = 1;
+                       mt9v032->vratio = 1;
+                       mt9v032_configure_pixel_rate(mt9v032);
+               }
        }
 
        *__crop = rect;
@@ -665,7 +684,7 @@ static int mt9v032_registered(struct v4l2_subdev *subdev)
        dev_info(&client->dev, "MT9V032 detected at address 0x%02x\n",
                        client->addr);
 
-       mt9v032_configure_pixel_rate(mt9v032, 1);
+       mt9v032_configure_pixel_rate(mt9v032);
 
        return ret;
 }
@@ -824,6 +843,9 @@ static int mt9v032_probe(struct i2c_client *client,
        mt9v032->format.field = V4L2_FIELD_NONE;
        mt9v032->format.colorspace = V4L2_COLORSPACE_SRGB;
 
+       mt9v032->hratio = 1;
+       mt9v032->vratio = 1;
+
        mt9v032->aec_agc = MT9V032_AEC_ENABLE | MT9V032_AGC_ENABLE;
        mt9v032->hblank = MT9V032_HORIZONTAL_BLANKING_DEF;
        mt9v032->sysclk = MT9V032_SYSCLK_FREQ_DEF;