media: atomisp-gc2235: use v4l2_find_nearest_size()

Instead of reinventing the wheel, use v4l2_find_nearest_size()
in order to get the closest resolution.

This should address a bug where the wrong resolution was
selected.
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

drivers/staging/media/atomisp/i2c/atomisp-gc2235.c

@@ -670,76 +670,6 @@ static int gc2235_s_power(struct v4l2_subdev *sd, int on)
 	return ret;
 }
 
-/*
- * distance - calculate the distance
- * @res: resolution
- * @w: width
- * @h: height
- *
- * Get the gap between resolution and w/h.
- * res->width/height smaller than w/h wouldn't be considered.
- * Returns the value of gap or -1 if fail.
- */
-#define LARGEST_ALLOWED_RATIO_MISMATCH 800
-static int distance(struct gc2235_resolution *res, u32 w, u32 h)
-{
-	unsigned int w_ratio = (res->width << 13) / w;
-	unsigned int h_ratio;
-	int match;
-
-	if (h == 0)
-		return -1;
-	h_ratio = (res->height << 13) / h;
-	if (h_ratio == 0)
-		return -1;
-	match   = abs(((w_ratio << 13) / h_ratio) - 8192);
-
-	if ((w_ratio < 8192) || (h_ratio < 8192) ||
-	    (match > LARGEST_ALLOWED_RATIO_MISMATCH))
-		return -1;
-
-	return w_ratio + h_ratio;
-}
-
-/* Return the nearest higher resolution index */
-static int nearest_resolution_index(int w, int h)
-{
-	int i;
-	int idx = -1;
-	int dist;
-	int min_dist = INT_MAX;
-	struct gc2235_resolution *tmp_res = NULL;
-
-	for (i = 0; i < N_RES; i++) {
-		tmp_res = &gc2235_res[i];
-		dist = distance(tmp_res, w, h);
-		if (dist == -1)
-			continue;
-		if (dist < min_dist) {
-			min_dist = dist;
-			idx = i;
-		}
-	}
-
-	return idx;
-}
-
-static int get_resolution_index(int w, int h)
-{
-	int i;
-
-	for (i = 0; i < N_RES; i++) {
-		if (w != gc2235_res[i].width)
-			continue;
-		if (h != gc2235_res[i].height)
-			continue;
-
-		return i;
-	}
-
-	return -1;
-}
-
 static int startup(struct v4l2_subdev *sd)
 {
 	struct gc2235_device *dev = to_gc2235_sensor(sd);
@@ -758,7 +688,7 @@ static int startup(struct v4l2_subdev *sd)
 		gc2235_write_reg_array(client, gc2235_init_settings);
 	}
 
-	ret = gc2235_write_reg_array(client, gc2235_res[dev->fmt_idx].regs);
+	ret = gc2235_write_reg_array(client, dev->res->regs);
 	if (ret) {
 		dev_err(&client->dev, "gc2235 write register err.\n");
 		return ret;
@@ -776,8 +706,8 @@ static int gc2235_set_fmt(struct v4l2_subdev *sd,
 	struct gc2235_device *dev = to_gc2235_sensor(sd);
 	struct i2c_client *client = v4l2_get_subdevdata(sd);
 	struct camera_mipi_info *gc2235_info = NULL;
+	struct gc2235_resolution *res;
 	int ret = 0;
-	int idx;
 
 	gc2235_info = v4l2_get_subdev_hostdata(sd);
 	if (!gc2235_info)
@@ -786,16 +716,18 @@ static int gc2235_set_fmt(struct v4l2_subdev *sd,
 		return -EINVAL;
 	if (!fmt)
 		return -EINVAL;
+
 	mutex_lock(&dev->input_lock);
-	idx = nearest_resolution_index(fmt->width, fmt->height);
-	if (idx == -1) {
-		/* return the largest resolution */
-		fmt->width = gc2235_res[N_RES - 1].width;
-		fmt->height = gc2235_res[N_RES - 1].height;
-	} else {
-		fmt->width = gc2235_res[idx].width;
-		fmt->height = gc2235_res[idx].height;
-	}
+	res = v4l2_find_nearest_size(gc2235_res_preview,
+				     ARRAY_SIZE(gc2235_res_preview), width,
+				     height, fmt->width, fmt->height);
+	if (!res)
+		res = &gc2235_res_preview[N_RES - 1];
+
+	fmt->width = res->width;
+	fmt->height = res->height;
+	dev->res = res;
+
 	fmt->code = MEDIA_BUS_FMT_SGRBG10_1X10;
 	if (format->which == V4L2_SUBDEV_FORMAT_TRY) {
 		sd_state->pads->try_fmt = *fmt;
@@ -803,13 +735,6 @@ static int gc2235_set_fmt(struct v4l2_subdev *sd,
 		return 0;
 	}
 
-	dev->fmt_idx = get_resolution_index(fmt->width, fmt->height);
-	if (dev->fmt_idx == -1) {
-		dev_err(&client->dev, "get resolution fail\n");
-		mutex_unlock(&dev->input_lock);
-		return -EINVAL;
-	}
-
 	ret = startup(sd);
 	if (ret) {
 		dev_err(&client->dev, "gc2235 startup err\n");
@@ -817,7 +742,7 @@ static int gc2235_set_fmt(struct v4l2_subdev *sd,
 	}
 
 	ret = gc2235_get_intg_factor(client, gc2235_info,
-				     &gc2235_res[dev->fmt_idx]);
+				     dev->res);
 	if (ret)
 		dev_err(&client->dev, "failed to get integration_factor\n");
 
@@ -839,8 +764,8 @@ static int gc2235_get_fmt(struct v4l2_subdev *sd,
 	if (!fmt)
 		return -EINVAL;
 
-	fmt->width = gc2235_res[dev->fmt_idx].width;
-	fmt->height = gc2235_res[dev->fmt_idx].height;
+	fmt->width = dev->res->width;
+	fmt->height = dev->res->height;
 	fmt->code = MEDIA_BUS_FMT_SGRBG10_1X10;
 
 	return 0;
@@ -953,7 +878,7 @@ static int gc2235_g_frame_interval(struct v4l2_subdev *sd,
 	struct gc2235_device *dev = to_gc2235_sensor(sd);
 
 	interval->interval.numerator = 1;
-	interval->interval.denominator = gc2235_res[dev->fmt_idx].fps;
+	interval->interval.denominator = dev->res->fps;
 
 	return 0;
 }
@@ -991,7 +916,7 @@ static int gc2235_g_skip_frames(struct v4l2_subdev *sd, u32 *frames)
 	struct gc2235_device *dev = to_gc2235_sensor(sd);
 
 	mutex_lock(&dev->input_lock);
-	*frames = gc2235_res[dev->fmt_idx].skip_frames;
+	*frames = dev->res->skip_frames;
 	mutex_unlock(&dev->input_lock);
 
 	return 0;
@@ -1055,7 +980,7 @@ static int gc2235_probe(struct i2c_client *client)
 
 	mutex_init(&dev->input_lock);
 
-	dev->fmt_idx = 0;
+	dev->res = &gc2235_res_preview[0];
 	v4l2_i2c_subdev_init(&dev->sd, client, &gc2235_ops);
 
 	gcpdev = gmin_camera_platform_data(&dev->sd,

drivers/staging/media/atomisp/i2c/gc2235.h

@@ -158,11 +158,10 @@ struct gc2235_device {
 	struct v4l2_mbus_framefmt format;
 	struct mutex input_lock;
 	struct v4l2_ctrl_handler ctrl_handler;
+	struct gc2235_resolution *res;
 
 	struct camera_sensor_platform_data *platform_data;
 	int vt_pix_clk_freq_mhz;
-	int fmt_idx;
-	u8 res;
 	u8 type;
 };