From: Michal Simek <michal.simek@xilinx.com>
To: linux-kernel@vger.kernel.org, monstr@monstr.eu
Cc: Yasir-Khan <yasir_khan@mentor.com>,
"Sören Brinkmann" <soren.brinkmann@xilinx.com>,
"Jiri Slaby" <jslaby@suse.com>,
linux-serial@vger.kernel.org,
"Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
linux-arm-kernel@lists.infradead.org
Subject: [PATCH] serial: xuartps: Enable uart loopback mode
Date: Mon, 23 Jan 2017 13:26:08 +0100 [thread overview]
Message-ID: <db906bd31d3db0e29d87cd545e4c4e9096106bcc.1485174366.git.michal.simek@xilinx.com> (raw)
From: Yasir-Khan <yasir_khan@mentor.com>
This patch adds xilinx uart loopback support by modifying the
cdns_uart_set_mctrl function to handle the switch to loopback mode.
After this patch, the loopback mode can be enabled/disabled by
setting/clearing the TIOCM_LOOP modem bit via TIOCMBIS/TIOCMBIC
ioctls respectively.
Signed-off-by: Yasir-Khan <yasir_khan@mentor.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
---
drivers/tty/serial/xilinx_uartps.c | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/drivers/tty/serial/xilinx_uartps.c b/drivers/tty/serial/xilinx_uartps.c
index dd4c02fa4820..ad77d0ed0c46 100644
--- a/drivers/tty/serial/xilinx_uartps.c
+++ b/drivers/tty/serial/xilinx_uartps.c
@@ -93,6 +93,7 @@
#define CDNS_UART_MR_CLKSEL 0x00000001 /* Pre-scalar selection */
#define CDNS_UART_MR_CHMODE_L_LOOP 0x00000200 /* Local loop back mode */
#define CDNS_UART_MR_CHMODE_NORM 0x00000000 /* Normal mode */
+#define CDNS_UART_MR_CHMODE_MASK 0x00000300 /* Mask for mode bits */
#define CDNS_UART_MR_STOPMODE_2_BIT 0x00000080 /* 2 stop bits */
#define CDNS_UART_MR_STOPMODE_1_BIT 0x00000000 /* 1 stop bit */
@@ -998,17 +999,25 @@ static unsigned int cdns_uart_get_mctrl(struct uart_port *port)
static void cdns_uart_set_mctrl(struct uart_port *port, unsigned int mctrl)
{
u32 val;
+ u32 mode_reg;
val = readl(port->membase + CDNS_UART_MODEMCR);
+ mode_reg = readl(port->membase + CDNS_UART_MR);
val &= ~(CDNS_UART_MODEMCR_RTS | CDNS_UART_MODEMCR_DTR);
+ mode_reg &= ~CDNS_UART_MR_CHMODE_MASK;
if (mctrl & TIOCM_RTS)
val |= CDNS_UART_MODEMCR_RTS;
if (mctrl & TIOCM_DTR)
val |= CDNS_UART_MODEMCR_DTR;
+ if (mctrl & TIOCM_LOOP)
+ mode_reg |= CDNS_UART_MR_CHMODE_L_LOOP;
+ else
+ mode_reg |= CDNS_UART_MR_CHMODE_NORM;
writel(val, port->membase + CDNS_UART_MODEMCR);
+ writel(mode_reg, port->membase + CDNS_UART_MR);
}
#ifdef CONFIG_CONSOLE_POLL
--
1.9.1
reply other threads:[~2017-01-23 12:26 UTC|newest]
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