1 files changed, 31 insertions, 2 deletions

diff --git a/drivers/i2c/busses/i2c-ocores.c b/drivers/i2c/busses/i2c-ocores.c
index c3dabee0aa35..4117f1abc7c6 100644
--- a/drivers/i2c/busses/i2c-ocores.c
+++ b/drivers/i2c/busses/i2c-ocores.c
@@ -35,6 +35,7 @@ struct ocores_i2c {
 	int iobase;
 	u32 reg_shift;
 	u32 reg_io_width;
+	unsigned long flags;
 	wait_queue_head_t wait;
 	struct i2c_adapter adap;
 	struct i2c_msg *msg;
@@ -82,6 +83,9 @@ struct ocores_i2c {
 
 #define TYPE_OCORES		0
 #define TYPE_GRLIB		1
+#define TYPE_SIFIVE_REV0	2
+
+#define OCORES_FLAG_BROKEN_IRQ BIT(1) /* Broken IRQ for FU540-C000 SoC */
 
 static void oc_setreg_8(struct ocores_i2c *i2c, int reg, u8 value)
 {
@@ -235,9 +239,12 @@ static irqreturn_t ocores_isr(int irq, void *dev_id)
 	struct ocores_i2c *i2c = dev_id;
 	u8 stat = oc_getreg(i2c, OCI2C_STATUS);
 
-	if (!(stat & OCI2C_STAT_IF))
+	if (i2c->flags & OCORES_FLAG_BROKEN_IRQ) {
+		if ((stat & OCI2C_STAT_IF) && !(stat & OCI2C_STAT_BUSY))
+			return IRQ_NONE;
+	} else if (!(stat & OCI2C_STAT_IF)) {
 		return IRQ_NONE;
-
+	}
 	ocores_process(i2c, stat);
 
 	return IRQ_HANDLED;
@@ -352,6 +359,11 @@ static void ocores_process_polling(struct ocores_i2c *i2c)
 		ret = ocores_isr(-1, i2c);
 		if (ret == IRQ_NONE)
 			break; /* all messages have been transferred */
+		else {
+			if (i2c->flags & OCORES_FLAG_BROKEN_IRQ)
+				if (i2c->state == STATE_DONE)
+					break;
+		}
 	}
 }
 
@@ -462,6 +474,14 @@ static const struct of_device_id ocores_i2c_match[] = {
 		.compatible = "aeroflexgaisler,i2cmst",
 		.data = (void *)TYPE_GRLIB,
 	},
+	{
+		.compatible = "sifive,fu540-c000-i2c",
+		.data = (void *)TYPE_SIFIVE_REV0,
+	},
+	{
+		.compatible = "sifive,i2c0",
+		.data = (void *)TYPE_SIFIVE_REV0,
+	},
 	{},
 };
 MODULE_DEVICE_TABLE(of, ocores_i2c_match);
@@ -586,6 +606,7 @@ static int ocores_i2c_probe(struct platform_device *pdev)
 {
 	struct ocores_i2c *i2c;
 	struct ocores_i2c_platform_data *pdata;
+	const struct of_device_id *match;
 	struct resource *res;
 	int irq;
 	int ret;
@@ -668,6 +689,14 @@ static int ocores_i2c_probe(struct platform_device *pdev)
 	irq = platform_get_irq(pdev, 0);
 	if (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;