[RFC PATCH 2/4] media: ti-vpe: cal: use v4l2_get_link_freq() for DPHY timing configuration

[Andrey Konovalov <andrey.konovalov@linaro.org>]

To configure DPHY properly the driver needs to know CSI-2 link frequency.
Instead of calculating it from the value of V4L2_CID_PIXEL_RATE control
(which can give wrong link frequency value for some sensors) call
v4l2_get_link_freq(). It uses V4L2_CID_LINK_FREQ if this control is
implemented in the sensor driver, and falls back to calculating it from
V4L2_CID_PIXEL_RATE otherwise.

Signed-off-by: Andrey Konovalov <andrey.konovalov@linaro.org>
---
 drivers/media/platform/ti-vpe/cal-camerarx.c | 47 +++++++-------------
 1 file changed, 17 insertions(+), 30 deletions(-)

diff --git a/drivers/media/platform/ti-vpe/cal-camerarx.c b/drivers/media/platform/ti-vpe/cal-camerarx.c
index dd48017859cd..0c1046a1fea4 100644
--- a/drivers/media/platform/ti-vpe/cal-camerarx.c
+++ b/drivers/media/platform/ti-vpe/cal-camerarx.c
@@ -45,22 +45,20 @@ static inline void camerarx_write(struct cal_camerarx *phy, u32 offset, u32 val)
  * ------------------------------------------------------------------
  */
 
-static s64 cal_camerarx_get_external_rate(struct cal_camerarx *phy)
+static s64 cal_camerarx_get_link_freq(struct cal_camerarx *phy)
 {
-	struct v4l2_ctrl *ctrl;
-	s64 rate;
+	u32 num_lanes = phy->endpoint.bus.mipi_csi2.num_data_lanes;
+	s64 freq;
 
-	ctrl = v4l2_ctrl_find(phy->sensor->ctrl_handler, V4L2_CID_PIXEL_RATE);
-	if (!ctrl) {
-		phy_err(phy, "no pixel rate control in subdev: %s\n",
+	freq = v4l2_get_link_freq(phy->sensor->ctrl_handler, phy->fmtinfo->bpp,
+				  num_lanes * 2);
+	if (freq < 0)
+		phy_err(phy, "failed to get link frequency from subdev: %s\n",
 			phy->sensor->name);
-		return -EPIPE;
-	}
-
-	rate = v4l2_ctrl_g_ctrl_int64(ctrl);
-	phy_dbg(3, phy, "sensor Pixel Rate: %llu\n", rate);
+	else
+		phy_dbg(3, phy, "sensor link frequency: %lld\n", freq);
 
-	return rate;
+	return freq;
 }
 
 static void cal_camerarx_lane_config(struct cal_camerarx *phy)
@@ -116,25 +114,14 @@ void cal_camerarx_disable(struct cal_camerarx *phy)
 #define TCLK_MISS	1
 #define TCLK_SETTLE	14
 
-static void cal_camerarx_config(struct cal_camerarx *phy, s64 external_rate)
+static void cal_camerarx_config(struct cal_camerarx *phy, s64 link_freq)
 {
 	unsigned int reg0, reg1;
 	unsigned int ths_term, ths_settle;
 	unsigned int csi2_ddrclk_khz;
-	struct v4l2_fwnode_bus_mipi_csi2 *mipi_csi2 =
-			&phy->endpoint.bus.mipi_csi2;
-	u32 num_lanes = mipi_csi2->num_data_lanes;
 
 	/* DPHY timing configuration */
-
-	/*
-	 * CSI-2 is DDR and we only count used lanes.
-	 *
-	 * csi2_ddrclk_khz = external_rate / 1000
-	 *		   / (2 * num_lanes) * phy->fmtinfo->bpp;
-	 */
-	csi2_ddrclk_khz = div_s64(external_rate * phy->fmtinfo->bpp,
-				  2 * num_lanes * 1000);
+	csi2_ddrclk_khz = div_s64(link_freq, 1000);
 
 	phy_dbg(1, phy, "csi2_ddrclk_khz: %d\n", csi2_ddrclk_khz);
 
@@ -270,14 +257,14 @@ static void cal_camerarx_ppi_disable(struct cal_camerarx *phy)
 
 static int cal_camerarx_start(struct cal_camerarx *phy)
 {
-	s64 external_rate;
+	s64 link_freq;
 	u32 sscounter;
 	u32 val;
 	int ret;
 
-	external_rate = cal_camerarx_get_external_rate(phy);
-	if (external_rate < 0)
-		return external_rate;
+	link_freq = cal_camerarx_get_link_freq(phy);
+	if (link_freq < 0)
+		return link_freq;
 
 	ret = v4l2_subdev_call(phy->sensor, core, s_power, 1);
 	if (ret < 0 && ret != -ENOIOCTLCMD && ret != -ENODEV) {
@@ -325,7 +312,7 @@ static int cal_camerarx_start(struct cal_camerarx *phy)
 	camerarx_read(phy, CAL_CSI2_PHY_REG0);
 
 	/* Program the PHY timing parameters. */
-	cal_camerarx_config(phy, external_rate);
+	cal_camerarx_config(phy, link_freq);
 
 	/*
 	 *    b. Assert the FORCERXMODE signal.
-- 
2.17.1