add handling for parity and character size config.

i wanted to talk modbus to a thing using a uchcom rs485 adapter,
but i needed even parity enabled to do that which the code didnt
support. this pulls in the necessary changes from netbsd uchcom.c
r1.26. it does not pull in the reset changes in 1.26 because netbsd
r1.28 reverts the reset code back to what we have now.

existing functionality tested by felix kronlage-dammers
ok patrick@

diff --git a/sys/dev/usb/uchcom.c b/sys/dev/usb/uchcom.c
index a9dc1f7..5609ca2 100644 (file)
--- a/sys/dev/usb/uchcom.c
+++ b/sys/dev/usb/uchcom.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: uchcom.c,v 1.28 2020/07/31 10:49:33 mglocker Exp $    */
+/*     $OpenBSD: uchcom.c,v 1.29 2021/11/02 09:52:40 dlg Exp $ */
 /*     $NetBSD: uchcom.c,v 1.1 2007/09/03 17:57:37 tshiozak Exp $      */
 
 /*
@@ -72,9 +72,8 @@ int   uchcomdebug = 0;
 #define UCHCOM_REG_BPS_DIV     0x13
 #define UCHCOM_REG_BPS_MOD     0x14
 #define UCHCOM_REG_BPS_PAD     0x0F
-#define UCHCOM_REG_BREAK1      0x05
-#define UCHCOM_REG_BREAK2      0x18
-#define UCHCOM_REG_LCR1                0x18
+#define UCHCOM_REG_BREAK       0x05
+#define UCHCOM_REG_LCR         0x18
 #define UCHCOM_REG_LCR2                0x25
 
 #define UCHCOM_VER_20          0x20
@@ -83,11 +82,25 @@ int uchcomdebug = 0;
 #define UCHCOM_BPS_MOD_BASE    20000000
 #define UCHCOM_BPS_MOD_BASE_OFS        1100
 
+#define UCHCOM_BPS_PRE_IMM     0x80    /* CH341: immediate RX forwarding */
+
 #define UCHCOM_DTR_MASK                0x20
 #define UCHCOM_RTS_MASK                0x40
 
-#define UCHCOM_BRK1_MASK       0x01
-#define UCHCOM_BRK2_MASK       0x40
+#define UCHCOM_BREAK_MASK      0x01
+
+#define UCHCOM_LCR_CS5         0x00
+#define UCHCOM_LCR_CS6         0x01
+#define UCHCOM_LCR_CS7         0x02
+#define UCHCOM_LCR_CS8         0x03
+#define UCHCOM_LCR_STOPB       0x04
+#define UCHCOM_LCR_PARENB      0x08
+#define UCHCOM_LCR_PARODD      0x00
+#define UCHCOM_LCR_PAREVEN     0x10
+#define UCHCOM_LCR_PARMARK     0x20
+#define UCHCOM_LCR_PARSPACE    0x30
+#define UCHCOM_LCR_TXE         0x40
+#define UCHCOM_LCR_RXE         0x80
 
 #define UCHCOM_INTR_STAT1      0x02
 #define UCHCOM_INTR_STAT2      0x03
@@ -577,23 +590,21 @@ int
 uchcom_set_break(struct uchcom_softc *sc, int onoff)
 {
        usbd_status err;
-       uint8_t brk1, brk2;
+       uint8_t brk, lcr;
 
-       err = uchcom_read_reg(sc, UCHCOM_REG_BREAK1, &brk1, UCHCOM_REG_BREAK2,
-           &brk2);
+       err = uchcom_read_reg(sc, UCHCOM_REG_BREAK, &brk, UCHCOM_REG_LCR, &lcr);
        if (err)
                return EIO;
        if (onoff) {
                /* on - clear bits */
-               brk1 &= ~UCHCOM_BRK1_MASK;
-               brk2 &= ~UCHCOM_BRK2_MASK;
+               brk &= ~UCHCOM_BREAK_MASK;
+               lcr &= ~UCHCOM_LCR_TXE;
        } else {
                /* off - set bits */
-               brk1 |= UCHCOM_BRK1_MASK;
-               brk2 |= UCHCOM_BRK2_MASK;
+               brk |= UCHCOM_BREAK_MASK;
+               lcr |= UCHCOM_LCR_TXE;
        }
-       err = uchcom_write_reg(sc, UCHCOM_REG_BREAK1, brk1, UCHCOM_REG_BREAK2,
-           brk2);
+       err = uchcom_write_reg(sc, UCHCOM_REG_BREAK, brk, UCHCOM_REG_LCR, lcr);
        if (err)
                return EIO;
 
@@ -665,23 +676,50 @@ uchcom_set_dte_rate(struct uchcom_softc *sc, uint32_t rate)
 int
 uchcom_set_line_control(struct uchcom_softc *sc, tcflag_t cflag)
 {
-       /*
-        * XXX: it is difficult to handle the line control appropriately:
-        *   work as chip default - CS8, no parity, !CSTOPB
-        *   other modes are not supported.
-        */
+       usbd_status err;
+       uint8_t lcr = 0, lcr2 = 0;
+
+       err = uchcom_read_reg(sc, UCHCOM_REG_LCR, &lcr,
+           UCHCOM_REG_LCR2, &lcr2);
+       if (err) {
+               printf("%s: cannot get LCR: %s\n",
+                   sc->sc_dev.dv_xname, usbd_errstr(err));
+               return EIO;
+       }
+
+       lcr = UCHCOM_LCR_RXE | UCHCOM_LCR_TXE;
 
        switch (ISSET(cflag, CSIZE)) {
        case CS5:
+               lcr |= UCHCOM_LCR_CS5;
+               break;
        case CS6:
+               lcr |= UCHCOM_LCR_CS6;
+               break;
        case CS7:
-               return EINVAL;
+               lcr |= UCHCOM_LCR_CS7;
+               break;
        case CS8:
+               lcr |= UCHCOM_LCR_CS8;
                break;
        }
 
-       if (ISSET(cflag, PARENB) || ISSET(cflag, CSTOPB))
-               return EINVAL;
+       if (ISSET(cflag, PARENB)) {
+               lcr |= UCHCOM_LCR_PARENB;
+               if (!ISSET(cflag, PARODD))
+                       lcr |= UCHCOM_LCR_PAREVEN;
+       }
+
+       if (ISSET(cflag, CSTOPB)) {
+               lcr |= UCHCOM_LCR_STOPB;
+       }
+
+       err = uchcom_write_reg(sc, UCHCOM_REG_LCR, lcr, UCHCOM_REG_LCR2, lcr2);
+       if (err) {
+               printf("%s: cannot set LCR: %s\n",
+                   sc->sc_dev.dv_xname, usbd_errstr(err));
+               return EIO;
+       }
 
        return 0;
 }