patch "serial: mvebu-uart: fix driver's tx_empty callback" added to tty-linus

This is a note to let you know that I've just added the patch titled

serial: mvebu-uart: fix driver's tx_empty callback

to my tty git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty.git
in the tty-linus branch.

The patch will show up in the next release of the linux-next tree (usually sometime within the next 24 hours during the week.)

The patch will hopefully also be merged in Linus's tree for the next -rc kernel release.

If you have any questions about this process, please let me know.

From 74e1eb3b4a1ef2e564b4bdeb6e92afe844e900de Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Pali=20Roh=C3=A1r?= <[email protected]>
Date: Sat, 11 Sep 2021 15:20:17 +0200
Subject: serial: mvebu-uart: fix driver's tx_empty callback
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Driver's tx_empty callback should signal when the transmit shift register is empty. So when the last character has been sent.

STAT_TX_FIFO_EMP bit signals only that HW transmit FIFO is empty, which happens when the last byte is loaded into transmit shift register.

STAT_TX_EMP bit signals when the both HW transmit FIFO and transmit shift register are empty.

So replace STAT_TX_FIFO_EMP check by STAT_TX_EMP in mvebu_uart_tx_empty() callback function.

---
 drivers/tty/serial/mvebu-uart.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

index 231de29a6452..ab226da75f7b 100644
@@ -163,7 +163,7 @@ static unsigned int mvebu_uart_tx_empty(struct uart_port *port)
 	st = readl(port->membase + UART_STAT);
 	spin_unlock_irqrestore(&port->lock, flags);
 
-	return (st & STAT_TX_FIFO_EMP) ? TIOCSER_TEMT : 0;
+	return (st & STAT_TX_EMP) ? TIOCSER_TEMT : 0;
 }
 
 static unsigned int mvebu_uart_get_mctrl(struct uart_port *port)

2.33.0