[PATCH AUTOSEL 4.14 213/371] serial: stm32: fix transmit_chars when tx is stopped

Sasha Levin
2020-01-16T18:22:36Z

From: Erwan Le Ray <erwan.leray@st.com>

[ Upstream commit b83b957c91f68e53f0dc596e129e8305761f2a32 ]

Disables the tx irq when the transmission is ended and updates stop_tx
conditions for code cleanup.

Fixes: 48a6092fb41f ("serial: stm32-usart: Add STM32 USART Driver")
Signed-off-by: Erwan Le Ray <erwan.leray@st.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/tty/serial/stm32-usart.c | 11 +++--------
1 file changed, 3 insertions(+), 8 deletions(-)

diff --git a/drivers/tty/serial/stm32-usart.c b/drivers/tty/serial/stm32-usart.c
index c43590077372..a1e31913bcf9 100644
--- a/drivers/tty/serial/stm32-usart.c
+++ b/drivers/tty/serial/stm32-usart.c
@@ -310,13 +310,8 @@ static void stm32_transmit_chars(struct uart_port *port)
return;
}

- if (uart_tx_stopped(port)) {
- stm32_stop_tx(port);
- return;
- }
-
- if (uart_circ_empty(xmit)) {
- stm32_stop_tx(port);
+ if (uart_circ_empty(xmit) || uart_tx_stopped(port)) {
+ stm32_clr_bits(port, ofs->cr1, USART_CR1_TXEIE);
return;
}

@@ -329,7 +324,7 @@ static void stm32_transmit_chars(struct uart_port *port)
uart_write_wakeup(port);

if (uart_circ_empty(xmit))
- stm32_stop_tx(port);
+ stm32_clr_bits(port, ofs->cr1, USART_CR1_TXEIE);
}

static irqreturn_t stm32_interrupt(int irq, void *ptr)
--
2.20.1