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[v3,6/7] i2c: img-scb: Clear line and interrupt status before starting a transfer

Message ID 1441896607-16310-7-git-send-email-sifan.naeem@imgtec.com
State Accepted
Headers show

Commit Message

Sifan Naeem Sept. 10, 2015, 2:50 p.m. UTC 
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@imgtec.com>
Acked-by: James Hogan <james.hogan@imgtec.com>
Reviewed-by: James Hartley <james.hartley@imgtec.com>
---
 drivers/i2c/busses/i2c-img-scb.c |    9 +++++++++
 1 file changed, 9 insertions(+)
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Patch

diff --git a/drivers/i2c/busses/i2c-img-scb.c b/drivers/i2c/busses/i2c-img-scb.c
index 049d193d01ac..0fa47158dbe4 100644
--- a/drivers/i2c/busses/i2c-img-scb.c
+++ b/drivers/i2c/busses/i2c-img-scb.c
@@ -1060,6 +1060,15 @@  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)