V4L/DVB (12173): mt9v011: properly calculate image resolution registers

Instead of working with a table of precalculated values, fill them with
the proper values. Also, adds format functions that allow changing the
resolution, by cropping the image to the center of the sensor.

While here, move the sensor version check to the probe routine, to
indicate to the caller if the sensor is not supported by this driver.

Also, fixes a stupid bug where we're using &buffer[] instead of
buffer[].
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/video/mt9v011.c

@@ -56,6 +56,7 @@ static struct v4l2_queryctrl mt9v011_qctrl[] = {
 
 struct mt9v011 {
 	struct v4l2_subdev sd;
+	unsigned width, height;
 
 	u16 global_gain, red_bal, blue_bal;
 };
@@ -103,7 +104,7 @@ static void mt9v011_write(struct v4l2_subdev *sd, unsigned char addr,
 
 	v4l2_dbg(2, debug, sd,
 		 "mt9v011: writing 0x%02x 0x%04x\n", buffer[0], value);
-	rc = i2c_master_send(c, &buffer, 3);
+	rc = i2c_master_send(c, buffer, 3);
 	if (rc != 3)
 		v4l2_dbg(0, debug, sd,
 			 "i2c i/o error: rc == %d (should be 3)\n", rc);
@@ -123,12 +124,6 @@ static const struct i2c_reg_value mt9v011_init_default[] = {
 		{ R0D_MT9V011_RESET, 0x0001 },
 		{ R0D_MT9V011_RESET, 0x0000 },
 
-		{ R01_MT9V011_ROWSTART, 0x0008 },
-		{ R02_MT9V011_COLSTART, 0x0014 },
-		{ R03_MT9V011_HEIGHT, 0x01e0 },
-		{ R04_MT9V011_WIDTH, 0x0280 },
-		{ R05_MT9V011_HBLANK, 0x007b },
-		{ R06_MT9V011_VBLANK, 0x001c },
 		{ R09_MT9V011_SHUTTER_WIDTH, 0x0418 },
 		{ R0A_MT9V011_CLK_SPEED, 0x0000 },
 		{ R0C_MT9V011_SHUTTER_DELAY, 0x0000 },
@@ -171,25 +166,40 @@ static void set_balance(struct v4l2_subdev *sd)
 	mt9v011_write(sd, R2D_MT9V011_RED_GAIN, red_gain);
 }
 
-static int mt9v011_reset(struct v4l2_subdev *sd, u32 val)
+static void set_res(struct v4l2_subdev *sd)
 {
-	u16 version;
-	int i;
+	struct mt9v011 *core = to_mt9v011(sd);
+	unsigned vstart, hstart;
 
-	version = mt9v011_read(sd, R00_MT9V011_CHIP_VERSION);
+	/*
+	 * The mt9v011 doesn't have scaling. So, in order to select the desired
+	 * resolution, we're cropping at the middle of the sensor.
+	 * hblank and vblank should be adjusted, in order to warrant that
+	 * we'll preserve the line timings for 30 fps, no matter what resolution
+	 * is selected.
+	 */
 
-	if (version != MT9V011_VERSION) {
-		v4l2_info(sd, "*** unknown micron chip detected (0x%04x.\n",
-			  version);
-		return -EINVAL;
+	hstart = 14 + (640 - core->width) / 2;
+	mt9v011_write(sd, R02_MT9V011_COLSTART, hstart);
+	mt9v011_write(sd, R04_MT9V011_WIDTH, core->width);
+	mt9v011_write(sd, R05_MT9V011_HBLANK, 771 - core->width);
 
-	}
+	vstart = 8 + (640 - core->height) / 2;
+	mt9v011_write(sd, R01_MT9V011_ROWSTART, vstart);
+	mt9v011_write(sd, R03_MT9V011_HEIGHT, core->height);
+	mt9v011_write(sd, R06_MT9V011_VBLANK, 508 - core->height);
+};
+
+static int mt9v011_reset(struct v4l2_subdev *sd, u32 val)
+{
+	int i;
 
 	for (i = 0; i < ARRAY_SIZE(mt9v011_init_default); i++)
 		mt9v011_write(sd, mt9v011_init_default[i].reg,
 			       mt9v011_init_default[i].value);
 
 	set_balance(sd);
+	set_res(sd);
 
 	return 0;
 };
@@ -250,6 +260,50 @@ static int mt9v011_s_ctrl(struct v4l2_subdev *sd, struct v4l2_control *ctrl)
 	return 0;
 }
 
+static int mt9v011_enum_fmt(struct v4l2_subdev *sd, struct v4l2_fmtdesc *fmt)
+{
+	if (fmt->index > 0)
+		return -EINVAL;
+
+	fmt->flags = 0;
+	strcpy(fmt->description, "8 bpp Bayer GRGR..BGBG");
+	fmt->pixelformat = V4L2_PIX_FMT_SGRBG8;
+
+	return 0;
+}
+
+static int mt9v011_try_fmt(struct v4l2_subdev *sd, struct v4l2_format *fmt)
+{
+	struct v4l2_pix_format *pix = &fmt->fmt.pix;
+
+	if (pix->pixelformat != V4L2_PIX_FMT_SGRBG8)
+		return -EINVAL;
+
+	v4l_bound_align_image(&pix->width, 48, 639, 1,
+			      &pix->height, 32, 480, 1, 0);
+
+	return 0;
+}
+
+static int mt9v011_s_fmt(struct v4l2_subdev *sd, struct v4l2_format *fmt)
+{
+	struct v4l2_pix_format *pix = &fmt->fmt.pix;
+	struct mt9v011 *core = to_mt9v011(sd);
+	int rc;
+
+	rc = mt9v011_try_fmt(sd, fmt);
+	if (rc < 0)
+		return -EINVAL;
+
+	core->width = pix->width;
+	core->height = pix->height;
+
+	set_res(sd);
+
+	return 0;
+}
+
+
 #ifdef CONFIG_VIDEO_ADV_DEBUG
 static int mt9v011_g_register(struct v4l2_subdev *sd,
 			      struct v4l2_dbg_register *reg)
@@ -303,8 +357,15 @@ static const struct v4l2_subdev_core_ops mt9v011_core_ops = {
 #endif
 };
 
+static const struct v4l2_subdev_video_ops mt9v011_video_ops = {
+	.enum_fmt = mt9v011_enum_fmt,
+	.try_fmt = mt9v011_try_fmt,
+	.s_fmt = mt9v011_s_fmt,
+};
+
 static const struct v4l2_subdev_ops mt9v011_ops = {
 	.core  = &mt9v011_core_ops,
+	.video = &mt9v011_video_ops,
 };
 
 
@@ -315,6 +376,7 @@ static const struct v4l2_subdev_ops mt9v011_ops = {
 static int mt9v011_probe(struct i2c_client *c,
 			 const struct i2c_device_id *id)
 {
+	u16 version;
 	struct mt9v011 *core;
 	struct v4l2_subdev *sd;
 
@@ -327,10 +389,22 @@ static int mt9v011_probe(struct i2c_client *c,
 	if (!core)
 		return -ENOMEM;
 
-	core->global_gain = 0x0024;
-
 	sd = &core->sd;
 	v4l2_i2c_subdev_init(sd, c, &mt9v011_ops);
+
+	/* Check if the sensor is really a MT9V011 */
+	version = mt9v011_read(sd, R00_MT9V011_CHIP_VERSION);
+	if (version != MT9V011_VERSION) {
+		v4l2_info(sd, "*** unknown micron chip detected (0x%04x.\n",
+			  version);
+		kfree(core);
+		return -EINVAL;
+	}
+
+	core->global_gain = 0x0024;
+	core->width  = 640;
+	core->height = 480;
+
 	v4l_info(c, "chip found @ 0x%02x (%s)\n",
 		 c->addr << 1, c->adapter->name);