From: Baolin Wang Date: Wed, 21 Aug 2019 12:39:09 +0000 (+0800) Subject: serial: sprd: Add loopback function support X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=37ba760b6bb7402d8a8cce178063be78e3da474d;p=linux.git serial: sprd: Add loopback function support Add loopback function support for Spreadtrum serial controller. Signed-off-by: Baolin Wang Link: https://lore.kernel.org/r/1275cd9968f1ceb5ac049cc23f1e508025cd552f.1566375260.git.baolin.wang@linaro.org Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/tty/serial/sprd_serial.c b/drivers/tty/serial/sprd_serial.c index 284709f618318..de077d7b5f008 100644 --- a/drivers/tty/serial/sprd_serial.c +++ b/drivers/tty/serial/sprd_serial.c @@ -79,6 +79,7 @@ /* control register 1 */ #define SPRD_CTL1 0x001C #define SPRD_DMA_EN BIT(15) +#define SPRD_LOOPBACK_EN BIT(14) #define RX_HW_FLOW_CTL_THLD BIT(6) #define RX_HW_FLOW_CTL_EN BIT(7) #define TX_HW_FLOW_CTL_EN BIT(8) @@ -164,7 +165,14 @@ static unsigned int sprd_get_mctrl(struct uart_port *port) static void sprd_set_mctrl(struct uart_port *port, unsigned int mctrl) { - /* nothing to do */ + u32 val = serial_in(port, SPRD_CTL1); + + if (mctrl & TIOCM_LOOP) + val |= SPRD_LOOPBACK_EN; + else + val &= ~SPRD_LOOPBACK_EN; + + serial_out(port, SPRD_CTL1, val); } static void sprd_stop_rx(struct uart_port *port)