* Tony Lindgren <tony@xxxxxxxxxxx> [081031 12:21]:
> Otherwise we may race, or will get spurious I2C interrupts:
>
> i2c_omap.1: XDR IRQ while no data to send
> ...
Here's an updated version of this to say "flush posted write" for easy
grepping. Also change previous wmb() to flush.
Tony
>From df5cf408d3a59a892ba8ff25feed402fdeb53a0d Mon Sep 17 00:00:00 2001
From: Tony Lindgren <tony@xxxxxxxxxxx>
Date: Fri, 31 Oct 2008 13:56:16 -0700
Subject: [PATCH] I2C: Flush posted write for i2c-omap
Otherwise we may race, or will get spurious I2C interrupts:
i2c_omap.1: XDR IRQ while no data to send
...
Also replace previous wmb() with a readback to flush posted write
there too.
Signed-off-by: Tony Lindgren <tony@xxxxxxxxxxx>
diff --git a/drivers/i2c/busses/i2c-omap.c b/drivers/i2c/busses/i2c-omap.c
index a999606..6d40781 100644
--- a/drivers/i2c/busses/i2c-omap.c
+++ b/drivers/i2c/busses/i2c-omap.c
@@ -220,16 +220,14 @@ static void omap_i2c_idle(struct omap_i2c_dev *dev)
dev->iestate = omap_i2c_read_reg(dev, OMAP_I2C_IE_REG);
omap_i2c_write_reg(dev, OMAP_I2C_IE_REG, 0);
- if (dev->rev1)
+ if (dev->rev1) {
iv = omap_i2c_read_reg(dev, OMAP_I2C_IV_REG); /* Read clears */
- else
+ } else {
omap_i2c_write_reg(dev, OMAP_I2C_STAT_REG, dev->iestate);
- /*
- * The wmb() is to ensure that the I2C interrupt mask write
- * reaches the I2C controller before the dev->idle store
- * occurs.
- */
- wmb();
+
+ /* Flush posted write for interrupt mask before dev->idle = 1 */
+ omap_i2c_read_reg(dev, OMAP_I2C_STAT_REG);
+ }
dev->idle = 1;
clk_disable(dev->fclk);
if (dev->iclk != NULL)
@@ -689,6 +687,9 @@ omap_i2c_isr(int this_irq, void *dev_id)
break;
}
omap_i2c_write_reg(dev, OMAP_I2C_DATA_REG, w);
+
+ /* Flush posted write */
+ omap_i2c_read_reg(dev, OMAP_I2C_DATA_REG);
}
omap_i2c_ack_stat(dev,
stat & (OMAP_I2C_STAT_XRDY | OMAP_I2C_STAT_XDR));
