linux-kernel - [PATCH RFT 1/2] i2c: rcar: reset controller is mandatory for Gen3+

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Message-Id: <20230913062950.4968-2-wsa+renesas@sang-engineering.com>
Date:   Wed, 13 Sep 2023 08:29:48 +0200
From:   Wolfram Sang <wsa+renesas@...g-engineering.com>
To:     linux-renesas-soc@...r.kernel.org
Cc:     Wolfram Sang <wsa+renesas@...g-engineering.com>,
        Andi Shyti <andi.shyti@...nel.org>,
        Philipp Zabel <p.zabel@...gutronix.de>,
        linux-i2c@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH RFT 1/2] i2c: rcar: reset controller is mandatory for Gen3+

Initially, we only needed a reset controller to make sure RXDMA works at
least once per transfer. Meanwhile, documentation has been updated. It
now says that a reset has to be performed prior every transaction, also
if it is non-DMA. So, make the reset controller a requirement instead of
being optional.

Signed-off-by: Wolfram Sang <wsa+renesas@...g-engineering.com>
---
 drivers/i2c/busses/i2c-rcar.c | 22 +++++++++++-----------
 1 file changed, 11 insertions(+), 11 deletions(-)

diff --git a/drivers/i2c/busses/i2c-rcar.c b/drivers/i2c/busses/i2c-rcar.c
index 5e97635faf78..342c3747f415 100644
--- a/drivers/i2c/busses/i2c-rcar.c
+++ b/drivers/i2c/busses/i2c-rcar.c
@@ -838,12 +838,10 @@ static int rcar_i2c_master_xfer(struct i2c_adapter *adap,
 
 	/* Gen3 needs a reset before allowing RXDMA once */
 	if (priv->devtype == I2C_RCAR_GEN3) {
-		priv->flags |= ID_P_NO_RXDMA;
-		if (!IS_ERR(priv->rstc)) {
-			ret = rcar_i2c_do_reset(priv);
-			if (ret == 0)
-				priv->flags &= ~ID_P_NO_RXDMA;
-		}
+		priv->flags &= ~ID_P_NO_RXDMA;
+		ret = rcar_i2c_do_reset(priv);
+		if (ret)
+			priv->flags |= ID_P_NO_RXDMA;
 	}
 
 	rcar_i2c_init(priv);
@@ -1096,11 +1094,13 @@ static int rcar_i2c_probe(struct platform_device *pdev)
 
 	if (priv->devtype == I2C_RCAR_GEN3) {
 		priv->rstc = devm_reset_control_get_exclusive(&pdev->dev, NULL);
-		if (!IS_ERR(priv->rstc)) {
-			ret = reset_control_status(priv->rstc);
-			if (ret < 0)
-				priv->rstc = ERR_PTR(-ENOTSUPP);
-		}
+		if (IS_ERR(priv->rstc))
+			return dev_err_probe(&pdev->dev, PTR_ERR(priv->rstc),
+					     "couldn't get reset");
+
+		ret = reset_control_status(priv->rstc);
+		if (ret < 0)
+			return ret;
 	}
 
 	/* Stay always active when multi-master to keep arbitration working */
-- 
2.35.1