diff options
| author |   Michael Walle <michael@walle.cc> | 2021-05-12 16:12:54 +0200 |
|---|---|---|
| committer |   Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-05-13 16:08:26 +0200 |
| commit | 8a0c810d94f02d7aa2074658ee6d0ec0a39f0555 (patch) | |
| tree | 05e8ea36bbd5d05b9fa10e5850a924bd8d69f272 /drivers/tty/serial | |
| parent | serial: fsl_lpuart: remove manual RTSCTS control from 8-bit LPUART (diff) | |
| download | linux-dev-8a0c810d94f02d7aa2074658ee6d0ec0a39f0555.tar.xz linux-dev-8a0c810d94f02d7aa2074658ee6d0ec0a39f0555.zip | |
serial: fsl_lpuart: add loopback support
The LPUART can loop the RX and TX signal. Add support for it.
Please note, this was only tested on the 32 bit version of the LPUART.
Signed-off-by: Michael Walle <michael@walle.cc>
Link: https://lore.kernel.org/r/20210512141255.18277-9-michael@walle.cc
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty/serial')
| -rw-r--r-- | drivers/tty/serial/fsl_lpuart.c | 36 |
1 files changed, 34 insertions, 2 deletions
diff --git a/drivers/tty/serial/fsl_lpuart.c b/drivers/tty/serial/fsl_lpuart.c index 895766599b84..0d4eb0219728 100644 --- a/drivers/tty/serial/fsl_lpuart.c +++ b/drivers/tty/serial/fsl_lpuart.c @@ -1403,22 +1403,54 @@ static int lpuart32_config_rs485(struct uart_port *port, static unsigned int lpuart_get_mctrl(struct uart_port *port) { - return 0; + unsigned int mctrl = 0; + u8 reg; + + reg = readb(port->membase + UARTCR1); + if (reg & UARTCR1_LOOPS) + mctrl |= TIOCM_LOOP; + + return mctrl; } static unsigned int lpuart32_get_mctrl(struct uart_port *port) { - return 0; + unsigned int mctrl = 0; + u32 reg; + + reg = lpuart32_read(port, UARTCTRL); + if (reg & UARTCTRL_LOOPS) + mctrl |= TIOCM_LOOP; + + return mctrl; } static void lpuart_set_mctrl(struct uart_port *port, unsigned int mctrl) { + u8 reg; + + reg = readb(port->membase + UARTCR1); + + /* for internal loopback we need LOOPS=1 and RSRC=0 */ + reg &= ~(UARTCR1_LOOPS | UARTCR1_RSRC); + if (mctrl & TIOCM_LOOP) + reg |= UARTCR1_LOOPS; + writeb(reg, port->membase + UARTCR1); } static void lpuart32_set_mctrl(struct uart_port *port, unsigned int mctrl) { + u32 reg; + + reg = lpuart32_read(port, UARTCTRL); + + /* for internal loopback we need LOOPS=1 and RSRC=0 */ + reg &= ~(UARTCTRL_LOOPS | UARTCTRL_RSRC); + if (mctrl & TIOCM_LOOP) + reg |= UARTCTRL_LOOPS; + lpuart32_write(port, reg, UARTCTRL); } static void lpuart_break_ctl(struct uart_port *port, int break_state) |