media: rcar-csi2: Clarify usage of mbps and msps

The helper function to deal with calculating the link speed is designed
in such a way that it returns the correct type bps (bits per second) for
D-PHY and sps (symbols per second) for C-PHY. And for historical reasons
the function kept the name mbps.

This is confusing, fix it by having the function only deal with bps
values as this is the most common use-case and convert bps to sps in the
only function where it is needed to configure the C-PHY.

Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Tested-by: Tomi Valkeinen <tomi.valkeinen+renesas@ideasonboard.com>
Reviewed-by: Tomi Valkeinen <tomi.valkeinen+renesas@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Link: https://lore.kernel.org/r/20250612175904.1126717-2-niklas.soderlund+renesas@ragnatech.se
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>

diff --git a/drivers/media/platform/renesas/rcar-csi2.c b/drivers/media/platform/renesas/rcar-csi2.c
index 9979de4f6ef1cc379d37b1a50379d6e56857ae8f..358e7470befc741dfe763df70c213b012fe598d9 100644 (file)
--- a/drivers/media/platform/renesas/rcar-csi2.c
+++ b/drivers/media/platform/renesas/rcar-csi2.c
@@ -975,10 +975,6 @@ static int rcsi2_calc_mbps(struct rcar_csi2 *priv, unsigned int bpp,
 
        mbps = div_u64(freq * 2, MEGA);
 
-       /* Adjust for C-PHY, divide by 2.8. */
-       if (priv->cphy)
-               mbps = div_u64(mbps * 5, 14);
-
        return mbps;
 }
 
@@ -1203,9 +1199,13 @@ static int rcsi2_wait_phy_start_v4h(struct rcar_csi2 *priv, u32 match)
        return -ETIMEDOUT;
 }
 
-static int rcsi2_c_phy_setting_v4h(struct rcar_csi2 *priv, int msps)
+static int rcsi2_c_phy_setting_v4h(struct rcar_csi2 *priv, int mbps)
 {
        const struct rcsi2_cphy_setting *conf;
+       int msps;
+
+       /* Adjust for C-PHY symbols, divide by 2.8. */
+       msps = div_u64(mbps * 5, 14);
 
        for (conf = cphy_setting_table_r8a779g0; conf->msps != 0; conf++) {
                if (conf->msps > msps)
@@ -1301,7 +1301,7 @@ static int rcsi2_start_receiver_v4h(struct rcar_csi2 *priv,
        const struct rcar_csi2_format *format;
        const struct v4l2_mbus_framefmt *fmt;
        unsigned int lanes;
-       int msps;
+       int mbps;
        int ret;
 
        /* Use the format on the sink pad to compute the receiver config. */
@@ -1314,9 +1314,9 @@ static int rcsi2_start_receiver_v4h(struct rcar_csi2 *priv,
        if (ret)
                return ret;
 
-       msps = rcsi2_calc_mbps(priv, format->bpp, lanes);
-       if (msps < 0)
-               return msps;
+       mbps = rcsi2_calc_mbps(priv, format->bpp, lanes);
+       if (mbps < 0)
+               return mbps;
 
        /* Reset LINK and PHY*/
        rcsi2_write(priv, V4H_CSI2_RESETN_REG, 0);
@@ -1352,7 +1352,7 @@ static int rcsi2_start_receiver_v4h(struct rcar_csi2 *priv,
        rcsi2_write16(priv, V4H_PPI_RW_COMMON_CFG_REG, 0x0003);
 
        /* C-PHY settings */
-       ret = rcsi2_c_phy_setting_v4h(priv, msps);
+       ret = rcsi2_c_phy_setting_v4h(priv, mbps);
        if (ret)
                return ret;
 
@@ -1363,7 +1363,7 @@ static int rcsi2_start_receiver_v4h(struct rcar_csi2 *priv,
        return 0;
 }
 
-static int rcsi2_d_phy_setting_v4m(struct rcar_csi2 *priv, int data_rate)
+static int rcsi2_d_phy_setting_v4m(struct rcar_csi2 *priv, int mbps)
 {
        unsigned int timeout;
        int ret;