tty: serial: fsl_lpuart: add 7-bits format support on imx7ulp/imx8ulp/imx8qxp

imx7ulp/imx8ulp/imx8qxp lpuart IP support 7-bits format and have no
limitation on parity when CS7. Remove this limitation and add 7-bits
format support on imx7ulp/imx8ulp/imx8qxp.

Signed-off-by: Luke Wang <ziniu.wang_1@nxp.com>
Link: https://lore.kernel.org/r/20241008094418.439706-1-ziniu.wang_1@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/serial/fsl_lpuart.c b/drivers/tty/serial/fsl_lpuart.c
index c14a83c..57b0632 100644 (file)
--- a/drivers/tty/serial/fsl_lpuart.c
+++ b/drivers/tty/serial/fsl_lpuart.c
@@ -184,6 +184,7 @@
 #define UARTCTRL_SBK           0x00010000
 #define UARTCTRL_MA1IE         0x00008000
 #define UARTCTRL_MA2IE         0x00004000
+#define UARTCTRL_M7            0x00000800
 #define UARTCTRL_IDLECFG       GENMASK(10, 8)
 #define UARTCTRL_LOOPS         0x00000080
 #define UARTCTRL_DOZEEN                0x00000040
@@ -2222,8 +2223,9 @@ lpuart32_set_termios(struct uart_port *port, struct ktermios *termios,
        modem = lpuart32_read(&sport->port, UARTMODIR);
        sport->is_cs7 = false;
        /*
-        * only support CS8 and CS7, and for CS7 must enable PE.
+        * only support CS8 and CS7
         * supported mode:
+        *  - (7,n,1) (imx only)
         *  - (7,e/o,1)
         *  - (8,n,1)
         *  - (8,m/s,1)
@@ -2238,7 +2240,7 @@ lpuart32_set_termios(struct uart_port *port, struct ktermios *termios,
 
        if ((termios->c_cflag & CSIZE) == CS8 ||
                (termios->c_cflag & CSIZE) == CS7)
-               ctrl = old_ctrl & ~UARTCTRL_M;
+               ctrl = old_ctrl & ~(UARTCTRL_M | UARTCTRL_M7);
 
        if (termios->c_cflag & CMSPAR) {
                if ((termios->c_cflag & CSIZE) != CS8) {
@@ -2265,9 +2267,18 @@ lpuart32_set_termios(struct uart_port *port, struct ktermios *termios,
        else
                bd &= ~UARTBAUD_SBNS;
 
-       /* parity must be enabled when CS7 to match 8-bits format */
-       if ((termios->c_cflag & CSIZE) == CS7)
-               termios->c_cflag |= PARENB;
+       /*
+        * imx support 7-bits format, no limitation on parity when CS7
+        * for layerscape, parity must be enabled when CS7 to match 8-bits format
+        */
+       if ((termios->c_cflag & CSIZE) == CS7 && !(termios->c_cflag & PARENB)) {
+               if (is_imx7ulp_lpuart(sport) ||
+                   is_imx8ulp_lpuart(sport) ||
+                   is_imx8qxp_lpuart(sport))
+                       ctrl |= UARTCTRL_M7;
+               else
+                       termios->c_cflag |= PARENB;
+       }
 
        if ((termios->c_cflag & PARENB)) {
                if (termios->c_cflag & CMSPAR) {