i2c: hisi: Only handle the interrupt of the driver's transfer

The controller may be shared with other port, for example the firmware.
Handle the interrupt from other sources will cause crash since some
data are not initialized. So only handle the interrupt of the driver's
transfer and discard others.

Fixes: d62fbdb ("i2c: add support for HiSilicon I2C controller")
Signed-off-by: Yicong Yang <yangyicong@hisilicon.com>
Reviewed-by: Andi Shyti <andi.shyti@kernel.org>
Link: https://lore.kernel.org/r/20230801124625.63587-1-yangyicong@huawei.com
Signed-off-by: Wolfram Sang <wsa@kernel.org>

drivers/i2c/busses/i2c-hisi.c

@@ -330,6 +330,14 @@ static irqreturn_t hisi_i2c_irq(int irq, void *context)
 	struct hisi_i2c_controller *ctlr = context;
 	u32 int_stat;
 
+	/*
+	 * Don't handle the interrupt if cltr->completion is NULL. We may
+	 * reach here because the interrupt is spurious or the transfer is
+	 * started by another port (e.g. firmware) rather than us.
+	 */
+	if (!ctlr->completion)
+		return IRQ_NONE;
+
 	int_stat = readl(ctlr->iobase + HISI_I2C_INT_MSTAT);
 	hisi_i2c_clear_int(ctlr, int_stat);
 	if (!(int_stat & HISI_I2C_INT_ALL))