make CFG_TUH_CDC_LINE_CODING_ON_ENUM optional for ch34x

Author: hathach

examples/host/cdc_msc_hid/src/cdc_app.c

@@ -85,13 +85,17 @@ void tuh_cdc_mount_cb(uint8_t idx) {
          itf_info.desc.bInterfaceNumber);
 
 #ifdef CFG_TUH_CDC_LINE_CODING_ON_ENUM
-  // CFG_TUH_CDC_LINE_CODING_ON_ENUM must be defined for line coding is set by tinyusb in enumeration
-  // otherwise you need to call tuh_cdc_set_line_coding() first
+  // If CFG_TUH_CDC_LINE_CODING_ON_ENUM is defined, line coding will be set by tinyusb stack
+  // while eneumerating new cdc device
   cdc_line_coding_t line_coding = {0};
   if (tuh_cdc_get_local_line_coding(idx, &line_coding)) {
     printf("  Baudrate: %lu, Stop Bits : %u\r\n", line_coding.bit_rate, line_coding.stop_bits);
     printf("  Parity  : %u, Data Width: %u\r\n", line_coding.parity, line_coding.data_bits);
   }
+#else
+  // Set Line Coding upon mounted
+  cdc_line_coding_t new_line_coding = { 115200, CDC_LINE_CODING_STOP_BITS_1, CDC_LINE_CODING_PARITY_NONE, 8 };
+  tuh_cdc_set_line_coding(idx, &new_line_coding, NULL, 0);
 #endif
 }
 

src/class/cdc/cdc_host.c

@@ -1510,10 +1510,11 @@ static void ch34x_process_config(tuh_xfer_t* xfer) {
   uint8_t const idx = tuh_cdc_itf_get_index(xfer->daddr, itf_num);
   cdch_interface_t* p_cdc = get_itf(idx);
   uintptr_t const state = xfer->user_data;
-  cdc_line_coding_t const line_coding = CFG_TUH_CDC_LINE_CODING_ON_ENUM_CH34X;
   uint8_t buffer[2]; // TODO remove
   TU_ASSERT (p_cdc,);
 
+  // TODO check xfer->result
+
   switch (state) {
     case CONFIG_CH34X_READ_VERSION:
       TU_LOG_DRV("[%u] CDCh CH34x attempt to read Chip Version\r\n", p_cdc->daddr);
@@ -1527,20 +1528,28 @@ static void ch34x_process_config(tuh_xfer_t* xfer) {
       // only versions >= 0x30 are tested, below 0x30 seems having other programming, see drivers from WCH vendor, Linux kernel and FreeBSD
       TU_ASSERT (version >= 0x30,);
 
+      #ifdef CFG_TUH_CDC_LINE_CODING_ON_ENUM
+      cdc_line_coding_t const line_coding = CFG_TUH_CDC_LINE_CODING_ON_ENUM;
+      uint8_t const lcr = ch34x_get_lcr(line_coding.stop_bits, line_coding.parity, line_coding.data_bits);
+      uint16_t const first_arg = tu_u16(lcr, 0x9c);
       uint16_t const div_ps = ch34x_get_divisor_prescaler(line_coding.bit_rate);
       TU_ASSERT(div_ps != 0, );
-
-      uint8_t const lcr = ch34x_get_lcr(line_coding.stop_bits, line_coding.parity, line_coding.data_bits);
+      #else
+      uint16_t const first_arg = 0;
+      uint16_t const div_ps = 0;
+      #endif
 
       // Init CH34x with line coding
-      TU_ASSERT (ch34x_control_out(p_cdc, CH34X_REQ_SERIAL_INIT, tu_u16(lcr, 0x9c), div_ps,
+      TU_ASSERT (ch34x_control_out(p_cdc, CH34X_REQ_SERIAL_INIT, first_arg, div_ps,
                                    ch34x_process_config, CONFIG_CH34X_SPECIAL_REG_WRITE),);
       break;
     }
 
     case CONFIG_CH34X_SPECIAL_REG_WRITE:
       // do special reg write, purpose unknown, overtaken from WCH driver
-      p_cdc->line_coding = line_coding;
+      #ifdef CFG_TUH_CDC_LINE_CODING_ON_ENUM
+      p_cdc->line_coding = ((cdc_line_coding_t) CFG_TUH_CDC_LINE_CODING_ON_ENUM);
+      #endif
       TU_ASSERT (ch34x_write_reg(p_cdc, 0x0f2c, 0x0007, ch34x_process_config, CONFIG_CH34X_FLOW_CONTROL),);
       break;
 

src/class/cdc/serial/ch34x.h

@@ -27,21 +27,11 @@
 #ifndef _CH34X_H_
 #define _CH34X_H_
 
-// For simplicity, only the name CH34X is used here,
-// but specifically only CH340 and CH341 are supported.
-
-// There is no official documentation for the CH34x chips. Reference can be found
+// There is no official documentation for the CH34x (CH340, CH341) chips. Reference can be found
 // - https://github.com/WCHSoftGroup/ch341ser_linux
 // - https://github.com/torvalds/linux/blob/master/drivers/usb/serial/ch341.c
 // - https://github.com/freebsd/freebsd-src/blob/main/sys/dev/usb/serial/uchcom.c
 
-// set line_coding @ enumeration
-#ifdef CFG_TUH_CDC_LINE_CODING_ON_ENUM
-#define CFG_TUH_CDC_LINE_CODING_ON_ENUM_CH34X CFG_TUH_CDC_LINE_CODING_ON_ENUM
-#else // this default is necessary to work properly
-#define CFG_TUH_CDC_LINE_CODING_ON_ENUM_CH34X { 9600, CDC_LINE_CONDING_STOP_BITS_1, CDC_LINE_CODING_PARITY_NONE, 8 }
-#endif
-
 // USB requests
 #define CH34X_REQ_READ_VERSION 0x5F // dec  95
 #define CH34X_REQ_WRITE_REG    0x9A // dec 154