linux-kernel - [PATCH 1/1] i2c: ocores: fix polling mode workaround on FU540-C000 SoC

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Message-Id: <1602006796-273724-2-git-send-email-sagar.kadam@sifive.com>
Date:   Tue,  6 Oct 2020 10:53:16 -0700
From:   Sagar Shrikant Kadam <sagar.kadam@...ive.com>
To:     linux-kernel@...r.kernel.org
Cc:     linux-riscv@...ts.infradead.org, linux-i2c@...r.kernel.org,
        peter@...sgaard.com, andrew@...n.ch, paul.walmsley@...ive.com,
        palmer@...belt.com, aou@...s.berkeley.edu,
        Sagar Shrikant Kadam <sagar.kadam@...ive.com>
Subject: [PATCH 1/1] i2c: ocores: fix polling mode workaround on FU540-C000 SoC

The FU540-C000 has a broken IRQ and support was added earlier
so that it will operate in polling mode, but seems to work only
in case interrupts property is missing from the i2c0 dt-node.
This should not be the case and the driver should handle polling
mode with the interrupt property present in i2c0 node of the
device tree.
So check if it's the FU540-C000 soc and enable polling mode master
xfers, as the IRQ for this chip is broken.

Fixes commit c45d4ba86731 ("i2c: ocores: add polling mode workaround
for Sifive FU540-C000 SoC")

Signed-off-by: Sagar Shrikant Kadam <sagar.kadam@...ive.com>
---
 drivers/i2c/busses/i2c-ocores.c | 22 +++++++++++++---------
 1 file changed, 13 insertions(+), 9 deletions(-)

diff --git a/drivers/i2c/busses/i2c-ocores.c b/drivers/i2c/busses/i2c-ocores.c
index f5fc75b..4405244 100644
--- a/drivers/i2c/busses/i2c-ocores.c
+++ b/drivers/i2c/busses/i2c-ocores.c
@@ -686,17 +686,21 @@ static int ocores_i2c_probe(struct platform_device *pdev)
 
 	init_waitqueue_head(&i2c->wait);
 
+	/*
+	 * Set OCORES_FLAG_BROKEN_IRQ to enable workaround for
+	 * FU540-C000 SoC in polling mode.
+	 * Since the SoC does have interrupt it's dt has the interrupt
+	 * defined but it should be bypassed in driver as this SoC has
+	 * a broken IRQ, hence update the master_xfer to use polling
+	 * transfers.
+	 */
+	match = of_match_node(ocores_i2c_match, pdev->dev.of_node);
+	if (match && (long)match->data == TYPE_SIFIVE_REV0)
+		i2c->flags |= OCORES_FLAG_BROKEN_IRQ;
+
 	irq = platform_get_irq(pdev, 0);
-	if (irq == -ENXIO) {
+	if (i2c->flags == OCORES_FLAG_BROKEN_IRQ || irq == -ENXIO) {
 		ocores_algorithm.master_xfer = ocores_xfer_polling;
-
-		/*
-		 * Set in OCORES_FLAG_BROKEN_IRQ to enable workaround for
-		 * FU540-C000 SoC in polling mode.
-		 */
-		match = of_match_node(ocores_i2c_match, pdev->dev.of_node);
-		if (match && (long)match->data == TYPE_SIFIVE_REV0)
-			i2c->flags |= OCORES_FLAG_BROKEN_IRQ;
 	} else {
 		if (irq < 0)
 			return irq;
-- 
2.7.4