From 29fb08c300b5cb626b8a803440aab25d0983cab7 Mon Sep 17 00:00:00 2001 From: Shinya Kuribayashi Date: Wed, 24 Oct 2012 19:58:31 +0900 Subject: 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 Signed-off-by: Shinya Kuribayashi Signed-off-by: Wolfram Sang --- drivers/i2c/busses/i2c-sh_mobile.c | 3 +++ 1 file changed, 3 insertions(+) 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; } -- cgit v1.2.3