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

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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>
This commit is contained in:
Jun Chen 2012-11-07 12:04:04 -05:00 committed by Greg Kroah-Hartman
parent 1b2f8a9550
commit e8823f1ca8
1 changed files with 10 additions and 3 deletions
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13
drivers/tty/serial/ifx6x60.c
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@ -508,9 +508,16 @@ 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);
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;
}