Revert "i2c: bcm2835: Handle untimely DONE signal"

This reverts commit 431ac1d.

Reverting this patch because it appears to have caused a regression
when used with an MPU-9250 IMU.

See: Hexxeh/rpi-firmware#261

Signed-off-by: Phil Elwell <phil@raspberrypi.com>

drivers/i2c/busses/i2c-bcm2835.c

@@ -373,10 +373,6 @@ static irqreturn_t bcm2835_i2c_isr(int this_irq, void *data)
 	u32 val, err;
 
 	val = bcm2835_i2c_readl(i2c_dev, BCM2835_I2C_S);
-	bcm2835_i2c_writel(i2c_dev, BCM2835_I2C_S,
-			   BCM2835_I2C_S_CLKT |
-			   BCM2835_I2C_S_ERR |
-			   BCM2835_I2C_S_DONE);
 	bcm2835_debug_add(i2c_dev, val);
 
 	err = val & (BCM2835_I2C_S_CLKT | BCM2835_I2C_S_ERR);
@@ -386,20 +382,14 @@ static irqreturn_t bcm2835_i2c_isr(int this_irq, void *data)
 	}
 
 	if (val & BCM2835_I2C_S_DONE) {
-		if (val & BCM2835_I2C_S_TA)
-			return IRQ_HANDLED;
-
 		if (!i2c_dev->curr_msg) {
 			dev_err(i2c_dev->dev, "Got unexpected interrupt (from firmware?)\n");
 		} else if (i2c_dev->curr_msg->flags & I2C_M_RD) {
 			bcm2835_drain_rxfifo(i2c_dev);
 			val = bcm2835_i2c_readl(i2c_dev, BCM2835_I2C_S);
 		}
 
-		if (i2c_dev->msg_buf_remaining)
-			return IRQ_HANDLED;
-
-		if (val & BCM2835_I2C_S_RXD)
+		if ((val & BCM2835_I2C_S_RXD) || i2c_dev->msg_buf_remaining)
 			i2c_dev->msg_err = BCM2835_I2C_S_LEN;
 		else
 			i2c_dev->msg_err = 0;
@@ -436,6 +426,8 @@ static irqreturn_t bcm2835_i2c_isr(int this_irq, void *data)
 
 complete:
 	bcm2835_i2c_writel(i2c_dev, BCM2835_I2C_C, BCM2835_I2C_C_CLEAR);
+	bcm2835_i2c_writel(i2c_dev, BCM2835_I2C_S, BCM2835_I2C_S_CLKT |
+			   BCM2835_I2C_S_ERR | BCM2835_I2C_S_DONE);
 	complete(&i2c_dev->completion);
 
 	return IRQ_HANDLED;