Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752256AbdGRKDQ (ORCPT ); Tue, 18 Jul 2017 06:03:16 -0400 Received: from sci-ig2.spreadtrum.com ([222.66.158.135]:57854 "EHLO SHSQR01.spreadtrum.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1752188AbdGRKDO (ORCPT ); Tue, 18 Jul 2017 06:03:14 -0400 From: Chunyan Zhang To: Greg Kroah-Hartman CC: , , Lanqing Liu , Chunyan Zhang , Chunyan Zhang , Orson Zhai Subject: [PATCH] serial: sprd: clear timeout interrupt only rather than all interrupts Date: Tue, 18 Jul 2017 17:58:13 +0800 Message-ID: <20170718095813.32116-1-chunyan.zhang@spreadtrum.com> X-Mailer: git-send-email 2.12.2 MIME-Version: 1.0 Content-Type: text/plain X-MAIL: SHSQR01.spreadtrum.com v6IA1fXd071358 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1347 Lines: 40 From: Lanqing Liu 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 Signed-off-by: Chunyan Zhang --- 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 90996ad..f758fe6 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)) -- 2.7.4