1 files changed, 32 insertions, 11 deletions

diff --git a/drivers/usb/serial/pl2303.c b/drivers/usb/serial/pl2303.c
index e7a84f0f5179..bedf8e47713b 100644
--- a/drivers/usb/serial/pl2303.c
+++ b/drivers/usb/serial/pl2303.c
@@ -139,6 +139,7 @@ enum pl2303_type {
         HX_TA,          /* HX(A) / X(A) / TA version  */ /* TODO: improve */
         HXD_EA_RA_SA,   /* HXD / EA / RA / SA version */ /* TODO: improve */
         TB,             /* TB version */
+        HX_CLONE,       /* Cheap and less functional clone of the HX chip */
 };
 /*
  * NOTE: don't know the difference between type 0 and type 1,
@@ -206,8 +207,23 @@ static int pl2303_startup(struct usb_serial *serial)
                  * the device descriptors of the X/HX, HXD, EA, RA, SA, TA, TB
                  */
                 if (le16_to_cpu(serial->dev->descriptor.bcdDevice) == 0x300) {
-                        type = HX_TA;
-                        type_str = "X/HX/TA";
+                        /* Check if the device is a clone */
+                        pl2303_vendor_read(0x9494, 0, serial, buf);
+                        /*
+                         * NOTE: Not sure if this read is really needed.
+                         * The HX returns 0x00, the clone 0x02, but the Windows
+                         * driver seems to ignore the value and continues.
+                         */
+                        pl2303_vendor_write(0x0606, 0xaa, serial);
+                        pl2303_vendor_read(0x8686, 0, serial, buf);
+                        if (buf[0] != 0xaa) {
+                                type = HX_CLONE;
+                                type_str = "X/HX clone (limited functionality)";
+                        } else {
+                                type = HX_TA;
+                                type_str = "X/HX/TA";
+                        }
+                        pl2303_vendor_write(0x0606, 0x00, serial);
                 } else if (le16_to_cpu(serial->dev->descriptor.bcdDevice)
                                                                      == 0x400) {
                         type = HXD_EA_RA_SA;
@@ -305,8 +321,9 @@ static int pl2303_baudrate_encode_direct(int baud, enum pl2303_type type,
 {
         /*
          * NOTE: Only the values defined in baud_sup are supported !
-         *       => if unsupported values are set, the PL2303 seems to
-         *          use 9600 baud (at least my PL2303X always does)
+         * => if unsupported values are set, the PL2303 uses 9600 baud instead
+         * => HX clones just don't work at unsupported baud rates < 115200 baud,
+         *    for baud rates > 115200 they run at 115200 baud
          */
         const int baud_sup[] = { 75, 150, 300, 600, 1200, 1800, 2400, 3600,
                                  4800, 7200, 9600, 14400, 19200, 28800, 38400,
@@ -316,14 +333,14 @@ static int pl2303_baudrate_encode_direct(int baud, enum pl2303_type type,
          * NOTE: With the exception of type_0/1 devices, the following
          * additional baud rates are supported (tested with HX rev. 3A only):
          * 110*, 56000*, 128000, 134400, 161280, 201600, 256000*, 268800,
-         * 403200, 806400.      (*: not HX)
+         * 403200, 806400.      (*: not HX and HX clones)
          *
          * Maximum values: HXD, TB: 12000000; HX, TA: 6000000;
-         *                 type_0+1: 1228800; RA: 921600; SA: 115200
+         *                 type_0+1: 1228800; RA: 921600; HX clones, SA: 115200
          *
          * As long as we are not using this encoding method for anything else
-         * than the type_0+1 and HX chips, there is no point in complicating
-         * the code to support them.
+         * than the type_0+1, HX and HX clone chips, there is no point in
+         * complicating the code to support them.
          */
         int i;
 
@@ -347,6 +364,8 @@ static int pl2303_baudrate_encode_direct(int baud, enum pl2303_type type,
                 baud = min_t(int, baud, 6000000);
         else if (type == type_0 || type == type_1)
                 baud = min_t(int, baud, 1228800);
+        else if (type == HX_CLONE)
+                baud = min_t(int, baud, 115200);
         /* Direct (standard) baud rate encoding method */
         put_unaligned_le32(baud, buf);
 
@@ -359,7 +378,8 @@ static int pl2303_baudrate_encode_divisor(int baud, enum pl2303_type type,
         /*
          * Divisor based baud rate encoding method
          *
-         * NOTE: it's not clear if the type_0/1 chips support this method
+         * NOTE: HX clones do NOT support this method.
+         * It's not clear if the type_0/1 chips support it.
          *
          * divisor = 12MHz * 32 / baudrate = 2^A * B
          *
@@ -452,7 +472,7 @@ static void pl2303_encode_baudrate(struct tty_struct *tty,
          * 1) Direct method: encodes the baud rate value directly
          *    => supported by all chip types
          * 2) Divisor based method: encodes a divisor to a base value (12MHz*32)
-         *    => supported by HX chips (and likely not by type_0/1 chips)
+         *    => not supported by HX clones (and likely type_0/1 chips)
          *
          * NOTE: Although the divisor based baud rate encoding method is much
          * more flexible, some of the standard baud rate values can not be
@@ -460,7 +480,7 @@ static void pl2303_encode_baudrate(struct tty_struct *tty,
          * the device likely uses the same baud rate generator for both methods
          * so that there is likley no difference.
          */
-        if (type == type_0 || type == type_1)
+        if (type == type_0 || type == type_1 || type == HX_CLONE)
                 baud = pl2303_baudrate_encode_direct(baud, type, buf);
         else
                 baud = pl2303_baudrate_encode_divisor(baud, type, buf);
@@ -813,6 +833,7 @@ static void pl2303_break_ctl(struct tty_struct *tty, int break_state)
         result = usb_control_msg(serial->dev, usb_sndctrlpipe(serial->dev, 0),
                                  BREAK_REQUEST, BREAK_REQUEST_TYPE, state,
                                  0, NULL, 0, 100);
+        /* NOTE: HX clones don't support sending breaks, -EPIPE is returned */
         if (result)
                 dev_err(&port->dev, "error sending break = %d\n", result);
 }