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path: root/drivers/i2c/busses/i2c-mv64xxx.c
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Diffstat (limited to 'drivers/i2c/busses/i2c-mv64xxx.c')
-rw-r--r--drivers/i2c/busses/i2c-mv64xxx.c11
1 files changed, 11 insertions, 0 deletions
diff --git a/drivers/i2c/busses/i2c-mv64xxx.c b/drivers/i2c/busses/i2c-mv64xxx.c
index 047dfef7a657..878c076ebdc6 100644
--- a/drivers/i2c/busses/i2c-mv64xxx.c
+++ b/drivers/i2c/busses/i2c-mv64xxx.c
@@ -520,6 +520,17 @@ mv64xxx_i2c_intr(int irq, void *dev_id)
while (readl(drv_data->reg_base + drv_data->reg_offsets.control) &
MV64XXX_I2C_REG_CONTROL_IFLG) {
+ /*
+ * It seems that sometime the controller updates the status
+ * register only after it asserts IFLG in control register.
+ * This may result in weird bugs when in atomic mode. A delay
+ * of 100 ns before reading the status register solves this
+ * issue. This bug does not seem to appear when using
+ * interrupts.
+ */
+ if (drv_data->atomic)
+ ndelay(100);
+
status = readl(drv_data->reg_base + drv_data->reg_offsets.status);
mv64xxx_i2c_fsm(drv_data, status);
mv64xxx_i2c_do_action(drv_data);