serial: ifx6x60: ifx_spi_write don't need to do mrdy_assert when fifo is not empty.

This patch check whether the fifo lenth is empty before writing new data to fifo.If condition is true,ifx_spi_write need to trigger one mrdy_assert. If condition is false,the mrdy_assert will be trigger by the next ifx_spi_io.

---
 drivers/tty/serial/ifx6x60.c |   14 +++++++++++---
 1 files changed, 11 insertions(+), 3 deletions(-)

index 5b9bc19..aa01989 100644
@@ -469,9 +469,17 @@ static int ifx_spi_write(struct tty_struct *tty, const unsigned char *buf,
 {
 	struct ifx_spi_device *ifx_dev = tty->driver_data;
 	unsigned char *tmp_buf = (unsigned char *)buf;
-	int tx_count = kfifo_in_locked(&ifx_dev->tx_fifo, tmp_buf, count,
-				   &ifx_dev->fifo_lock);
-	mrdy_assert(ifx_dev);
+	int tx_count;
+	unsigned long flags;
+	bool is_fifo_empty;
+
+	spin_lock_irqsave(&ifx_dev->fifo_lock, flags);
+	is_fifo_empty = kfifo_is_empty(&ifx_dev->tx_fifo);
+	tx_count = kfifo_in(&ifx_dev->tx_fifo, tmp_buf, count);
+	spin_unlock_irqrestore(&ifx_dev->fifo_lock, flags);
+	if (is_fifo_empty)
+		mrdy_assert(ifx_dev);
+
 	return tx_count;
 }
 

1.7.4.1

What tree did you make this against? It doesn't apply to my tty-next tree at all :(

greg k-h

Hi,
I make this patch on your tty-next tree, Do I need to make it on the branch 3.7-rc6 against?

-----Original Message-----
From: Greg KH [mailto:[email protected]]
Sent: Friday, November 16, 2012 8:39 PM
To: Chen, Jun D
Cc: Alan Cox; Bi, Chao; serial; Gorby, Russ; [email protected]; Wu, Fengguang
Subject: Re: [PATCH] serial: ifx6x60: ifx_spi_write don't need to do mrdy_assert when fifo is not empty.

What tree did you make this against? It doesn't apply to my tty-next tree at all :(

greg k-h

http://daringfireball.net/2007/07/on_top

No, my tty-next branch. But something is odd, it didn't apply at all. Please try again.

thanks,

greg k-h