[PATCH 3/3] media: atmel: atmel-isi: initialize the try_crop for the pads in try_fmt

[<Eugen.Hristev@microchip.com>]

From: Eugen Hristev <eugen.hristev@microchip.com>

When requesting format from sensor, some sensors call the subdev_get_try_crop
which for ISI was not properly initialized, and this causes errors in
determining proper image resolutions.
To accommodate for this, when trying a format (in try_fmt), first attempt to
obtain the framesize for this format from sensor.
In case this fails, use the maximum ISI width/height as try_crop, otherwise
provide the first size height/width from the sensor.

Signed-off-by: Eugen Hristev <eugen.hristev@microchip.com>
---
 drivers/media/platform/atmel/atmel-isi.c | 27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/drivers/media/platform/atmel/atmel-isi.c b/drivers/media/platform/atmel/atmel-isi.c
index 59d4c9f..9b904f5 100644
--- a/drivers/media/platform/atmel/atmel-isi.c
+++ b/drivers/media/platform/atmel/atmel-isi.c
@@ -555,6 +555,30 @@ static const struct isi_format *find_format_by_fourcc(struct atmel_isi *isi,
 	return NULL;
 }
 
+static void isi_try_fse(struct atmel_isi *isi, const struct isi_format *isi_fmt,
+			struct v4l2_subdev_pad_config *pad_cfg)
+{
+	int ret;
+	struct v4l2_subdev_frame_size_enum fse = {
+		.code = isi_fmt->mbus_code,
+		.which = V4L2_SUBDEV_FORMAT_TRY,
+	};
+
+	ret = v4l2_subdev_call(isi->entity.subdev, pad, enum_frame_size,
+			       pad_cfg, &fse);
+	/*
+	 * Attempt to obtain format size from subdev. If not available,
+	 * just use the maximum ISI can receive.
+	 */
+	if (ret) {
+		pad_cfg->try_crop.width = MAX_SUPPORT_WIDTH;
+		pad_cfg->try_crop.height = MAX_SUPPORT_HEIGHT;
+	} else {
+		pad_cfg->try_crop.width = fse.max_width;
+		pad_cfg->try_crop.height = fse.max_height;
+	}
+}
+
 static int isi_try_fmt(struct atmel_isi *isi, struct v4l2_format *f,
 		       const struct isi_format **current_fmt)
 {
@@ -577,6 +601,9 @@ static int isi_try_fmt(struct atmel_isi *isi, struct v4l2_format *f,
 	pixfmt->height = clamp(pixfmt->height, 0U, MAX_SUPPORT_HEIGHT);
 
 	v4l2_fill_mbus_format(&format.format, pixfmt, isi_fmt->mbus_code);
+
+	isi_try_fse(isi, isi_fmt, &pad_cfg);
+
 	ret = v4l2_subdev_call(isi->entity.subdev, pad, set_fmt,
 			       &pad_cfg, &format);
 	if (ret < 0)
-- 
2.7.4