diff mbox series

[v4,06/27] media: ov5640: Update pixel_rate and link_freq

Message ID 20220223145603.121603-7-jacopo@jmondi.org (mailing list archive)
State New, archived
Headers show
Series media: ov5640: Rework the clock tree programming for MIPI | expand

Commit Message

Jacopo Mondi Feb. 23, 2022, 2:55 p.m. UTC 
After having set a new format re-calculate the pixel_rate and link_freq
control values and update them when in MIPI mode.

Take into account the limitation of the link frequency having to be
strictly smaller than 1GHz when computing the desired link_freq, and
adjust the resulting pixel_rate acounting for the clock tree
configuration.

Signed-off-by: Jacopo Mondi <jacopo@jmondi.org>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
---
 drivers/media/i2c/ov5640.c | 66 ++++++++++++++++++++++++++++++++++++--
 1 file changed, 64 insertions(+), 2 deletions(-)
diff mbox series

Patch

diff --git a/drivers/media/i2c/ov5640.c b/drivers/media/i2c/ov5640.c
index b1a282f453e3..17ad815f7bdf 100644
--- a/drivers/media/i2c/ov5640.c
+++ b/drivers/media/i2c/ov5640.c
@@ -31,6 +31,8 @@ 
 
 #define OV5640_DEFAULT_SLAVE_ID 0x3c
 
+#define OV5640_LINK_RATE_MAX		490000000U
+
 #define OV5640_REG_SYS_RESET02		0x3002
 #define OV5640_REG_SYS_CLOCK_ENABLE02	0x3006
 #define OV5640_REG_SYS_CTRL0		0x3008
@@ -2412,6 +2414,66 @@  static int ov5640_try_fmt_internal(struct v4l2_subdev *sd,
 	return 0;
 }
 
+static int ov5640_update_pixel_rate(struct ov5640_dev *sensor)
+{
+	const struct ov5640_mode_info *mode = sensor->current_mode;
+	struct v4l2_mbus_framefmt *fmt = &sensor->fmt;
+	enum ov5640_pixel_rate_id pixel_rate_id = mode->pixel_rate;
+	unsigned int i = 0;
+	u32 pixel_rate;
+	s64 link_freq;
+	u32 num_lanes;
+	u32 bpp;
+
+	/*
+	 * Update the pixel rate control value.
+	 *
+	 * For DVP mode, maintain the pixel rate calculation using fixed FPS.
+	 */
+	if (!ov5640_is_csi2(sensor)) {
+		__v4l2_ctrl_s_ctrl_int64(sensor->ctrls.pixel_rate,
+					 ov5640_calc_pixel_rate(sensor));
+
+		return 0;
+	}
+
+	/*
+	 * The MIPI CSI-2 link frequency should comply with the CSI-2
+	 * specification and be lower than 1GHz.
+	 *
+	 * Start from the suggested pixel_rate for the current mode and
+	 * progressively slow it down if it exceeds 1GHz.
+	 */
+	num_lanes = sensor->ep.bus.mipi_csi2.num_data_lanes;
+	bpp = ov5640_code_to_bpp(fmt->code);
+	do {
+		pixel_rate = ov5640_pixel_rates[pixel_rate_id];
+		link_freq = pixel_rate * bpp / (2 * num_lanes);
+	} while (link_freq >= 1000000000U &&
+		 ++pixel_rate_id < OV5640_NUM_PIXEL_RATES);
+
+	/*
+	 * Higher link rates require the clock tree to be programmed with
+	 * 'mipi_div' = 1; this has the effect of halving the actual output
+	 * pixel rate in the MIPI domain.
+	 *
+	 * Adjust the pixel rate control value to report it correctly to
+	 * userspace.
+	 */
+	if (link_freq > OV5640_LINK_RATE_MAX)
+		pixel_rate /= 2;
+
+	for (i = 0; i < ARRAY_SIZE(ov5640_csi2_link_freqs); ++i) {
+		if (ov5640_csi2_link_freqs[i] == link_freq)
+			break;
+	}
+
+	__v4l2_ctrl_s_ctrl_int64(sensor->ctrls.pixel_rate, pixel_rate);
+	__v4l2_ctrl_s_ctrl(sensor->ctrls.link_freq, i);
+
+	return 0;
+}
+
 static int ov5640_set_fmt(struct v4l2_subdev *sd,
 			  struct v4l2_subdev_state *sd_state,
 			  struct v4l2_subdev_format *format)
@@ -2451,8 +2513,8 @@  static int ov5640_set_fmt(struct v4l2_subdev *sd,
 	/* update format even if code is unchanged, resolution might change */
 	sensor->fmt = *mbus_fmt;
 
-	__v4l2_ctrl_s_ctrl_int64(sensor->ctrls.pixel_rate,
-				 ov5640_calc_pixel_rate(sensor));
+	ov5640_update_pixel_rate(sensor);
+
 out:
 	mutex_unlock(&sensor->lock);
 	return ret;