From 4350782570b919f254c1e083261a21c19fcaee90 Mon Sep 17 00:00:00 2001 From: Lanqing Liu <lanqing.liu@spreadtrum.com> Date: Tue, 18 Jul 2017 17:58:13 +0800 Subject: [PATCH] serial: sprd: clear timeout interrupt only rather than all interrupts On Spreadtrum's serial device, nearly all of interrupts would be cleared by hardware except timeout interrupt. This patch removed the operation of clearing all interrupt in irq handler, instead added an if statement to check if the timeout interrupt is supposed to be cleared. Wrongly clearing timeout interrupt would lead to uart data stay in rx fifo, that means the driver cannot read them out anymore. Signed-off-by: Lanqing Liu <lanqing.liu@spreadtrum.com> Signed-off-by: Chunyan Zhang <chunyan.zhang@spreadtrum.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- drivers/tty/serial/sprd_serial.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/tty/serial/sprd_serial.c b/drivers/tty/serial/sprd_serial.c index 90996ad97b371..f758fe68362c0 100644 --- a/drivers/tty/serial/sprd_serial.c +++ b/drivers/tty/serial/sprd_serial.c @@ -63,6 +63,7 @@ /* interrupt clear register */ #define SPRD_ICLR 0x0014 +#define SPRD_ICLR_TIMEOUT BIT(13) /* line control register */ #define SPRD_LCR 0x0018 @@ -298,7 +299,8 @@ static irqreturn_t sprd_handle_irq(int irq, void *dev_id) return IRQ_NONE; } - serial_out(port, SPRD_ICLR, ~0); + if (ims & SPRD_IMSR_TIMEOUT) + serial_out(port, SPRD_ICLR, SPRD_ICLR_TIMEOUT); if (ims & (SPRD_IMSR_RX_FIFO_FULL | SPRD_IMSR_BREAK_DETECT | SPRD_IMSR_TIMEOUT))