[PATCH 3.19.y-ckt 131/164] i2c: img-scb: Clear line and interrupt status before starting a transfer

From: Kamal Mostafa
Date: Wed Dec 02 2015 - 12:18:28 EST


3.19.8-ckt11 -stable review patch. If anyone has any objections, please let me know.

------------------

From: Sifan Naeem <sifan.naeem@xxxxxxxxxx>

commit 1ed6faedfc9741cca2d97b25ab73902ba7177093 upstream.

Clear line status and all generated interrupts from the interrupt
status register before starting a transfer, as we may have
unserviced interrupts from previous transfers that might be
handled in the context of the new transfer.

Fixes: commit 27bce457d588 ("i2c: img-scb: Add Imagination Technologies I2C SCB driver")
Signed-off-by: Sifan Naeem <sifan.naeem@xxxxxxxxxx>
Acked-by: James Hogan <james.hogan@xxxxxxxxxx>
Reviewed-by: James Hartley <james.hartley@xxxxxxxxxx>
Signed-off-by: Wolfram Sang <wsa@xxxxxxxxxxxxx>
Signed-off-by: Kamal Mostafa <kamal@xxxxxxxxxxxxx>
---
drivers/i2c/busses/i2c-img-scb.c | 9 +++++++++
1 file changed, 9 insertions(+)

diff --git a/drivers/i2c/busses/i2c-img-scb.c b/drivers/i2c/busses/i2c-img-scb.c
index 515cbb4..90ffb07 100644
--- a/drivers/i2c/busses/i2c-img-scb.c
+++ b/drivers/i2c/busses/i2c-img-scb.c
@@ -1058,6 +1058,15 @@ static int img_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
i2c->last_msg = (i == num - 1);
reinit_completion(&i2c->msg_complete);

+ /*
+ * Clear line status and all interrupts before starting a
+ * transfer, as we may have unserviced interrupts from
+ * previous transfers that might be handled in the context
+ * of the new transfer.
+ */
+ img_i2c_writel(i2c, SCB_INT_CLEAR_REG, ~0);
+ img_i2c_writel(i2c, SCB_CLEAR_REG, ~0);
+
if (atomic)
img_i2c_atomic_start(i2c);
else if (msg->flags & I2C_M_RD)
--
1.9.1

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