media: rcar-vin: Mask VNCSI_IFMD register

The VNCSI_IFMD register controls the data expansion mode and the
channel routing between the CSI-2 receivers and VIN instances.

According to the chip manual revision 2.20 not all fields are available
for all the SoCs:
- V3M, V3H and E3 do not support the DES1 field has they do not feature
  a CSI20 receiver.
- D3 only supports parallel input, and the whole register shall always
  be written as 0.

Inspect the per-SoC channel routing table where the available CSI-2
instances are reported and configure VNCSI_IFMD accordingly.

This patch supports this BSP change commit:

https://github.com/renesas-rcar/linux-bsp/commit/f54697394457
("media: rcar-vin: Fix VnCSI_IFMD register access for r8a77990")

[hverkuil: replace BSP commit ID with BSP URL]
Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Suggested-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Signed-off-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

drivers/media/platform/rcar-vin/rcar-dma.c

@@ -1448,7 +1448,9 @@ int rvin_dma_register(struct rvin_dev *vin, int irq)
  */
 int rvin_set_channel_routing(struct rvin_dev *vin, u8 chsel)
 {
-	u32 ifmd, vnmc;
+	const struct rvin_group_route *route;
+	u32 ifmd = 0;
+	u32 vnmc;
 	int ret;
 
 	ret = pm_runtime_get_sync(vin->dev);
@@ -1461,9 +1463,26 @@ int rvin_set_channel_routing(struct rvin_dev *vin, u8 chsel)
 	vnmc = rvin_read(vin, VNMC_REG);
 	rvin_write(vin, vnmc & ~VNMC_VUP, VNMC_REG);
 
-	ifmd = VNCSI_IFMD_DES1 | VNCSI_IFMD_DES0 | VNCSI_IFMD_CSI_CHSEL(chsel);
+	/*
+	 * Set data expansion mode to "pad with 0s" by inspecting the routes
+	 * table to find out which bit fields are available in the IFMD
+	 * register. IFMD_DES1 controls data expansion mode for CSI20/21,
+	 * IFMD_DES0 controls data expansion mode for CSI40/41.
+	 */
+	for (route = vin->info->routes; route->mask; route++) {
+		if (route->csi == RVIN_CSI20 || route->csi == RVIN_CSI21)
+			ifmd |= VNCSI_IFMD_DES1;
+		else
+			ifmd |= VNCSI_IFMD_DES0;
 
+		if (ifmd == (VNCSI_IFMD_DES0 | VNCSI_IFMD_DES1))
+			break;
+	}
+
+	if (ifmd) {
+		ifmd |= VNCSI_IFMD_CSI_CHSEL(chsel);
 		rvin_write(vin, ifmd, VNCSI_IFMD_REG);
+	}
 
 	vin_dbg(vin, "Set IFMD 0x%x\n", ifmd);