[PATCH] serial: xuartps: Enable uart loopback mode
From: Michal Simek <hidden>
Date: 2017-01-23 12:26:14
Also in:
linux-serial, lkml
Subsystem:
the rest, tty layer and serial drivers · Maintainers:
Linus Torvalds, Greg Kroah-Hartman, Jiri Slaby
From: Yasir-Khan <redacted> 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 <redacted> Signed-off-by: Michal Simek <redacted> --- 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
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1.9.1