serial_hid: add support for the WCH CH9325 chip (UT-D04 cables, UT32x)

Makefile.am

@@ -120,6 +120,7 @@ if NEED_SERIAL
 libsigrok_la_SOURCES += \
 	src/serial.c \
 	src/serial_hid.c \
+	src/serial_hid_ch9325.c \
 	src/serial_libsp.c \
 	src/scpi/scpi_serial.c
 endif

src/libsigrok-internal.h

@@ -751,6 +751,7 @@ struct sr_serial_dev_inst {
 #ifdef HAVE_LIBHIDAPI
 	enum ser_hid_chip_t {
 		SER_HID_CHIP_UNKNOWN,		/**!< place holder */
+		SER_HID_CHIP_WCH_CH9325,	/**!< WCH CH9325 */
 		SER_HID_CHIP_LAST,		/**!< sentinel */
 	} hid_chip;
 	struct ser_hid_chip_functions *hid_chip_funcs;
@@ -1217,6 +1218,7 @@ struct ser_hid_chip_functions {
 	int (*flush)(struct sr_serial_dev_inst *serial);
 	int (*drain)(struct sr_serial_dev_inst *serial);
 };
+extern SR_PRIV struct ser_hid_chip_functions *ser_hid_chip_funcs_ch9325;
 SR_PRIV const char *ser_hid_chip_find_name_vid_pid(uint16_t vid, uint16_t pid);
 #endif
 #endif

src/serial_hid.c

@@ -550,6 +550,7 @@ SR_PRIV int ser_hid_hidapi_set_data(struct sr_serial_dev_inst *serial,
 
 static struct ser_hid_chip_functions **chips[SER_HID_CHIP_LAST] = {
 	[SER_HID_CHIP_UNKNOWN] = NULL,
+	[SER_HID_CHIP_WCH_CH9325] = &ser_hid_chip_funcs_ch9325,
 };
 
 static struct ser_hid_chip_functions *get_hid_chip_funcs(enum ser_hid_chip_t chip)

src/serial_hid_ch9325.c

@@ -0,0 +1,176 @@
+/*
+ * This file is part of the libsigrok project.
+ *
+ * Copyright (C) 2017-2019 Gerhard Sittig <gerhard.sittig@gmx.net>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <config.h>
+#include <glib.h>
+#include <libsigrok/libsigrok.h>
+#include "libsigrok-internal.h"
+#include "serial_hid.h"
+#include <string.h>
+
+/** @cond PRIVATE */
+#define LOG_PREFIX "serial-ch9325"
+/** @endcond */
+
+#ifdef HAVE_SERIAL_COMM
+#ifdef HAVE_LIBHIDAPI
+
+/**
+ * @file
+ *
+ * Support serial-over-HID, specifically the WCH CH9325 chip.
+ */
+
+#define CH9325_MAX_BYTES_PER_REQUEST	7
+
+static const struct vid_pid_item vid_pid_items_ch9325[] = {
+	{ 0x1a86, 0xe008, },	/* CH9325 */
+	/*
+	 * Strictly speaking Hoitek HE2325U is a different chip, but
+	 * shares the programming model with WCH CH9325, and works
+	 * with the same support code.
+	 */
+	{ 0x04fa, 0x2490, },	/* HE2325U */
+	VID_PID_TERM,
+};
+
+static int ch9325_set_params(struct sr_serial_dev_inst *serial,
+	int baudrate, int bits, int parity, int stopbits,
+	int flowcontrol, int rts, int dtr)
+{
+	uint8_t report[6];
+	int replen;
+	int rc;
+	GString *text;
+
+	(void)parity;
+	(void)stopbits;
+	(void)flowcontrol;
+	(void)rts;
+	(void)dtr;
+
+	/*
+	 * Setup bitrate and frame format. Report layout:
+	 * (@-1, length 1, report number)
+	 * @0, length 2, bitrate (little endian format)
+	 * @2, length 1, unknown (parity? stop bits?)
+	 * @3, length 1, unknown (parity? stop bits?)
+	 * @4, length 1, data bits (0: 5, 1: 6, etc, 3: 8)
+	 */
+	replen = 0;
+	report[replen++] = 0;
+	WL16(&report[replen], baudrate);
+	replen += sizeof(uint16_t);
+	report[replen++] = 0x00;
+	report[replen++] = 0x00;
+	report[replen++] = bits - 5;
+	rc = ser_hid_hidapi_set_report(serial, report, replen);
+	text = sr_hexdump_new(report, replen);
+	sr_dbg("DBG: %s() report %s => rc %d", __func__, text->str, rc);
+	sr_hexdump_free(text);
+	if (rc < 0)
+		return SR_ERR;
+	if (rc != replen)
+		return SR_ERR;
+
+	return SR_OK;
+}
+
+static int ch9325_read_bytes(struct sr_serial_dev_inst *serial,
+	uint8_t *data, int space, unsigned int timeout)
+{
+	uint8_t buffer[1 + CH9325_MAX_BYTES_PER_REQUEST];
+	int rc;
+	int count;
+
+	/*
+	 * Check for available input data from the serial port.
+	 * Packet layout:
+	 * @0, length 1, number of bytes, OR-ed with 0xf0
+	 * @1, length N, data bytes (up to 7 bytes)
+	 */
+	rc = ser_hid_hidapi_get_data(serial, 2, buffer, sizeof(buffer), timeout);
+	if (rc < 0)
+		return SR_ERR;
+	if (rc == 0)
+		return 0;
+	sr_dbg("DBG: %s() got report len %d, 0x%02x.", __func__, rc, buffer[0]);
+
+	/* Check the length spec, get the byte count. */
+	count = buffer[0];
+	if ((count & 0xf0) != 0xf0)
+		return SR_ERR;
+	count &= 0x0f;
+	sr_dbg("DBG: %s(), got %d UART RX bytes.", __func__, count);
+	if (count > space)
+		return SR_ERR;
+
+	/* Pass received data bytes and their count to the caller. */
+	memcpy(data, &buffer[1], count);
+	return count;
+}
+
+static int ch9325_write_bytes(struct sr_serial_dev_inst *serial,
+	const uint8_t *data, int size)
+{
+	uint8_t buffer[1 + CH9325_MAX_BYTES_PER_REQUEST];
+	int rc;
+
+	sr_dbg("DBG: %s() shall send UART TX data, len %d.", __func__, size);
+
+	if (size < 1)
+		return 0;
+	if (size > CH9325_MAX_BYTES_PER_REQUEST) {
+		size = CH9325_MAX_BYTES_PER_REQUEST;
+		sr_dbg("DBG: %s() capping size to %d.", __func__, size);
+	}
+
+	/*
+	 * Packet layout to send serial data to the USB HID chip:
+	 * (@-1, length 1, report number)
+	 * @0, length 1, number of bytes, OR-ed with 0xf0
+	 * @1, length N, data bytes (up to 7 bytes)
+	 */
+	buffer[0] = size;	/* YES! TX is *without* 0xf0! */
+	memcpy(&buffer[1], data, size);
+	rc = ser_hid_hidapi_set_data(serial, 2, buffer, sizeof(buffer), 0);
+	if (rc < 0)
+		return rc;
+	if (rc == 0)
+		return 0;
+	return size;
+}
+
+static struct ser_hid_chip_functions chip_ch9325 = {
+	.chipname = "ch9325",
+	.chipdesc = "WCH CH9325",
+	.vid_pid_items = vid_pid_items_ch9325,
+	.max_bytes_per_request = CH9325_MAX_BYTES_PER_REQUEST,
+	.set_params = ch9325_set_params,
+	.read_bytes = ch9325_read_bytes,
+	.write_bytes = ch9325_write_bytes,
+};
+SR_PRIV struct ser_hid_chip_functions *ser_hid_chip_funcs_ch9325 = &chip_ch9325;
+
+#else
+
+SR_PRIV struct ser_hid_chip_functions *ser_hid_chip_funcs_ch9325 = NULL;
+
+#endif
+#endif