linux-kernel - [PATCH v7 07/13] media: cadence: csi2rx: Fix stream data configuration

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Date:   Tue, 14 Mar 2023 17:25:10 +0530
From:   Vaishnav Achath <vaishnav.a@...com>
To:     <linux-media@...r.kernel.org>, <devicetree@...r.kernel.org>,
        <mripard@...nel.org>, <mchehab@...nel.org>, <robh+dt@...nel.org>,
        <krzysztof.kozlowski+dt@...aro.org>,
        <laurent.pinchart@...asonboard.com>,
        <sakari.ailus@...ux.intel.com>, <tomi.valkeinen@...asonboard.com>
CC:     <linux-kernel@...r.kernel.org>, <bparrot@...com>,
        <niklas.soderlund+renesas@...natech.se>, <j-luthra@...com>,
        <devarsht@...com>, <praneeth@...com>, <u-kumar1@...com>,
        <vigneshr@...com>, <nm@...com>, <martyn.welch@...labora.com>,
        <vaishnav.a@...com>
Subject: [PATCH v7 07/13] media: cadence: csi2rx: Fix stream data configuration

From: Pratyush Yadav <p.yadav@...com>

Firstly, there is no VC_EN bit present in the STREAM_DATA_CFG register.
Bit 31 is part of the VL_SELECT field. Remove it completely.

Secondly, it makes little sense to enable ith virtual channel for ith
stream. Sure, there might be a use-case that demands it. But there might
also be a use case that demands all streams to use the 0th virtual
channel. Prefer this case over the former because it is less arbitrary
and also makes it very clear what the limitations of the current driver
is instead of giving a false impression that multiple virtual channels
are supported.

Signed-off-by: Pratyush Yadav <p.yadav@...com>
Signed-off-by: Vaishnav Achath <vaishnav.a@...com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@...asonboard.com>
---

(no changes since v1)

 drivers/media/platform/cadence/cdns-csi2rx.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/media/platform/cadence/cdns-csi2rx.c b/drivers/media/platform/cadence/cdns-csi2rx.c
index e80220840e93..f8ce9360bfb0 100644
--- a/drivers/media/platform/cadence/cdns-csi2rx.c
+++ b/drivers/media/platform/cadence/cdns-csi2rx.c
@@ -48,7 +48,6 @@
 #define CSI2RX_STREAM_STATUS_RDY			BIT(31)
 
 #define CSI2RX_STREAM_DATA_CFG_REG(n)		(CSI2RX_STREAM_BASE(n) + 0x008)
-#define CSI2RX_STREAM_DATA_CFG_EN_VC_SELECT		BIT(31)
 #define CSI2RX_STREAM_DATA_CFG_VC_SELECT(n)		BIT((n) + 16)
 
 #define CSI2RX_STREAM_CFG_REG(n)		(CSI2RX_STREAM_BASE(n) + 0x00c)
@@ -269,8 +268,11 @@ static int csi2rx_start(struct csi2rx_priv *csi2rx)
 		writel(CSI2RX_STREAM_CFG_FIFO_MODE_LARGE_BUF,
 		       csi2rx->base + CSI2RX_STREAM_CFG_REG(i));
 
-		writel(CSI2RX_STREAM_DATA_CFG_EN_VC_SELECT |
-		       CSI2RX_STREAM_DATA_CFG_VC_SELECT(i),
+		/*
+		 * Enable one virtual channel. When multiple virtual channels
+		 * are supported this will have to be changed.
+		 */
+		writel(CSI2RX_STREAM_DATA_CFG_VC_SELECT(0),
 		       csi2rx->base + CSI2RX_STREAM_DATA_CFG_REG(i));
 
 		writel(CSI2RX_STREAM_CTRL_START,
-- 
2.17.1