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.
Cc: Bi Chao <chao.bi@intel.com>
Signed-off-by: Chen Jun <jun.d.chen@intel.com>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/tty/serial/ifx6x60.c b/drivers/tty/serial/ifx6x60.c
index 21eb70b..1754c14 100644
--- a/drivers/tty/serial/ifx6x60.c
+++ b/drivers/tty/serial/ifx6x60.c
@@ -508,9 +508,16 @@
{
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);
+ 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);
+ int 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;
}