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authorShinya Kuribayashi <shinya.kuribayashi.px@renesas.com>2012-10-24 14:58:31 +0400
committerWolfram Sang <w.sang@pengutronix.de>2012-11-16 12:09:13 +0400
commit29fb08c300b5cb626b8a803440aab25d0983cab7 (patch)
tree334d4d82d2788c22e98f75e53ba9be4aa1416ada /drivers/i2c
parentebd5ac165f2aaefb767c53112c2010b0ff3df688 (diff)
downloadlinux-29fb08c300b5cb626b8a803440aab25d0983cab7.tar.xz
i2c: i2c-sh_mobile: fix spurious transfer request timed out
Ensure that any of preceding register write operations to the I2C hardware block reached the module, and the write data is reflected in the registers, before leaving the interrupt handler. Otherwise, we'll suffer from spurious WAIT interrupts that lead to 'Transfer request timed out' message, and the transaction failed. Reported-by: Teppei Kamijou <teppei.kamijou.yb@renesas.com> Signed-off-by: Shinya Kuribayashi <shinya.kuribayashi.px@renesas.com> Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
Diffstat (limited to 'drivers/i2c')
-rw-r--r--drivers/i2c/busses/i2c-sh_mobile.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/drivers/i2c/busses/i2c-sh_mobile.c b/drivers/i2c/busses/i2c-sh_mobile.c
index 4c283583bea0..9411c1b892c0 100644
--- a/drivers/i2c/busses/i2c-sh_mobile.c
+++ b/drivers/i2c/busses/i2c-sh_mobile.c
@@ -469,6 +469,9 @@ static irqreturn_t sh_mobile_i2c_isr(int irq, void *dev_id)
wake_up(&pd->wait);
}
+ /* defeat write posting to avoid spurious WAIT interrupts */
+ iic_rd(pd, ICSR);
+
return IRQ_HANDLED;
}