[PATCH 5.15 461/731] tty: serial: clean up stop-tx part in altera_uart_tx_chars()

Greg Kroah-Hartman
2022-12-28T15:28:00Z

From: Jiri Slaby <jslaby@suse.cz>

[ Upstream commit d9c128117da41cf4cb0e80ae565b5d3ac79dffac ]

The "stop TX" path in altera_uart_tx_chars() is open-coded, so:
* use uart_circ_empty() to check if the buffer is empty, and
* when true, call altera_uart_stop_tx().

Cc: Tobias Klauser <tklauser@distanz.ch>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Acked-by: Tobias Klauser <tklauser@distanz.ch>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20220920052049.20507-3-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Stable-dep-of: 1307c5d33cce ("serial: altera_uart: fix locking in polling mode")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/tty/serial/altera_uart.c | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/drivers/tty/serial/altera_uart.c b/drivers/tty/serial/altera_uart.c
index 7c5f4e966b59..0e194556d76e 100644
--- a/drivers/tty/serial/altera_uart.c
+++ b/drivers/tty/serial/altera_uart.c
@@ -272,10 +272,8 @@ static void altera_uart_tx_chars(struct altera_uart *pp)
if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
uart_write_wakeup(port);

- if (xmit->head == xmit->tail) {
- pp->imr &= ~ALTERA_UART_CONTROL_TRDY_MSK;
- altera_uart_update_ctrl_reg(pp);
- }
+ if (uart_circ_empty(xmit))
+ altera_uart_stop_tx(port);
}

static irqreturn_t altera_uart_interrupt(int irq, void *data)
--
2.35.1