i2c: mvtwsi: fix reading status register after interrupt

[platform/kernel/u-boot.git] / drivers / i2c / mvtwsi.c

diff --git a/drivers/i2c/mvtwsi.c b/drivers/i2c/mvtwsi.c
index 74ac0a4..0a2dafc 100644 (file)
--- a/drivers/i2c/mvtwsi.c
+++ b/drivers/i2c/mvtwsi.c
@@ -271,6 +271,17 @@ static int twsi_wait(struct mvtwsi_registers *twsi, int expected_status,
        do {
                control = readl(&twsi->control);
                if (control & MVTWSI_CONTROL_IFLG) {
+                       /*
+                        * On Armada 38x it seems that the controller works as
+                        * if it first set the MVTWSI_CONTROL_IFLAG in the
+                        * control register and only after that it changed the
+                        * status register.
+                        * This sometimes caused weird bugs which only appeared
+                        * on selected I2C speeds and even then only sometimes.
+                        * We therefore add here a simple ndealy(100), which
+                        * seems to fix this weird bug.
+                        */
+                       ndelay(100);
                        status = readl(&twsi->status);
                        if (status == expected_status)
                                return 0;