[PATCH 2/4] i2c: rockchip: ignore i2c transfers when another transfer is running

[Gerald Loacker <gerald.loacker@wolfvision.net>]

It may happen that an i2c transfer is requested by a callback although
there is an other i2c transfer running. In this case do not interrupt the
transfer and return with an error.

Signed-off-by: Gerald Loacker <gerald.loacker@wolfvision.net>
---
 drivers/i2c/busses/i2c-rockchip.c | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/drivers/i2c/busses/i2c-rockchip.c b/drivers/i2c/busses/i2c-rockchip.c
index 1bca3e9913..a869b9d0b7 100644
--- a/drivers/i2c/busses/i2c-rockchip.c
+++ b/drivers/i2c/busses/i2c-rockchip.c
@@ -369,7 +369,19 @@ static int rockchip_i2c_xfer(struct i2c_adapter *adapter, struct i2c_msg *msgs,
 {
 	struct rk_i2c *i2c = to_rk_i2c(adapter);
 	struct device *dev = &adapter->dev;
-	int i, ret = 0;
+	struct i2c_regs *regs = i2c->regs;
+	int i, ret = 0, val;
+
+	val = readl(&regs->con);
+	if (val & I2C_CON_EN) {
+		val = readl(&regs->con);
+		if (val & I2C_IPD_ALL_CLEAN) {
+			dev_dbg(dev,
+				"i2c_xfer: %d messages dropped due to pending interrupts\n",
+				nmsgs);
+			return -EAGAIN;
+		}
+	}
 
 	dev_dbg(dev, "i2c_xfer: %d messages\n", nmsgs);
 	for (i = 0; i < nmsgs; i++) {

-- 
2.37.2