Add generic ftdi GPIO backend

This permits driving a board controlled by GPIOs on an FTDI
interface.

Also add a sample 99-libftdi.rules to permit using the FTDI device.

Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>

99-libftdi.rules

@@ -0,0 +1 @@
+SUBSYSTEMS=="usb", ATTRS{idVendor}=="0403", ATTRS{idProduct}=="6011", GROUP="dialout", MODE="0660"

Makefile

@@ -6,12 +6,12 @@ SERVER := cdba-server
 all: $(CLIENT) $(SERVER)
 
 CFLAGS := -Wall -g -O2
-LDFLAGS := -ludev -lyaml
+LDFLAGS := -ludev -lyaml -lftdi -lusb
 
 CLIENT_SRCS := cdba.c circ_buf.c
 CLIENT_OBJS := $(CLIENT_SRCS:.c=.o)
 
-SERVER_SRCS := cdba-server.c cdb_assist.c circ_buf.c conmux.c device.c device_parser.c fastboot.c alpaca.c console.c qcomlt_dbg.c
+SERVER_SRCS := cdba-server.c cdb_assist.c circ_buf.c conmux.c device.c device_parser.c fastboot.c alpaca.c ftdi-gpio.c console.c qcomlt_dbg.c
 SERVER_OBJS := $(SERVER_SRCS:.c=.o)
 
 $(CLIENT): $(CLIENT_OBJS)

device_parser.c

@@ -34,6 +34,7 @@
 
 #include "device.h"
 #include "alpaca.h"
+#include "ftdi-gpio.h"
 #include "cdb_assist.h"
 #include "conmux.h"
 #include "console.h"
@@ -117,6 +118,13 @@ static void parse_board(struct device_parser *dp)
 			dev->power = alpaca_power;
 			dev->usb = alpaca_usb;
 			dev->key = alpaca_key;
+		} else if (!strcmp(key, "ftdi_gpio")) {
+			dev->control_dev = strdup(value);
+
+			dev->open = ftdi_gpio_open;
+			dev->power = ftdi_gpio_power;
+			dev->usb = ftdi_gpio_usb;
+			dev->key = ftdi_gpio_key;
 		} else if (!strcmp(key, "qcomlt_debug_board")) {
 			dev->control_dev = strdup(value);
 

ftdi-gpio.c

@@ -0,0 +1,252 @@
+/*
+ * Copyright (c) 2023, Linaro Ltd.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ * this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ * this list of conditions and the following disclaimer in the documentation
+ * and/or other materials provided with the distribution.
+ *
+ * 3. Neither the name of the copyright holder nor the names of its contributors
+ * may be used to endorse or promote products derived from this software without
+ * specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+#include <sys/socket.h>
+#include <sys/types.h>
+#include <arpa/inet.h>
+#include <ctype.h>
+#include <err.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+
+#include "cdba-server.h"
+#include "ftdi-gpio.h"
+
+#include "ftdi.h"
+
+enum {
+	GPIO_POWER = 0,			// Power input enable
+	GPIO_FASTBOOT_KEY,		// Usually volume key
+	GPIO_POWER_KEY,			// Key to power the device
+	GPIO_USB_DISCONNECT,		// Simulate main USB connection
+	GPIO_COUNT
+};
+
+enum {
+	GPIO_ACTIVE_HIGH = 0,
+	GPIO_ACTIVE_LOW,
+};
+
+struct ftdi_gpio {
+	struct ftdi_context *gpio;
+	char *ftdi_device;
+	unsigned int ftdi_interface;
+	unsigned int gpio_present[GPIO_COUNT];
+	unsigned int gpio_offset[GPIO_COUNT];
+	unsigned int gpio_polarity[GPIO_COUNT];
+	unsigned char gpio_lines;
+};
+
+static int ftdi_gpio_device_power(struct ftdi_gpio *ftdi_gpio, bool on);
+static void ftdi_gpio_device_usb(struct ftdi_gpio *ftdi_gpio, bool on);
+
+/*
+ * fdio_gpio parameter: <libftdi description>;[<interface>[;<gpios>...]]
+ * - libftdi description: "s:0xVEND:0xPROD:SERIAL"
+ * - interface: A, B, C or D (default A)
+ * - gpios: type,id,polarity
+ *   - type: POWER, FASTBOOT_KEY, POWER_KEY or USB_DISCONNECT
+ *   - id: 0, 1, 2, 3, 4, 5, 6 or 7
+ *   - polarity: ACTIVE_HIGH or ACTIVE_LOW
+ *
+ * Example: s:0xVEND:0xPROD:SERIAL;D;POWER,0,ACTIVE_LOW;FASTBOOT_KEY,1,ACTIVE_HIGH;POWER_KEY,2,ACTIVE_HIGH;USB_DISCONNECT,3,ACTIVE_LOW
+ */
+
+static void ftdi_gpio_parse_config(struct ftdi_gpio *ftdi_gpio, char *control_dev)
+{
+	char *c, *interface;
+	size_t device_len;
+
+	// First libftdi description
+	c = strchr(control_dev, ';');
+	if (!c)
+		device_len = strlen(control_dev);
+	else
+		device_len = c - control_dev;
+
+	ftdi_gpio->ftdi_device = strndup(control_dev, device_len);
+
+	if (!c)
+		return;
+
+	// Interface
+	interface = c + 1;
+	if (*interface != 'A' &&
+	    *interface != 'A' &&
+	    *interface != 'C' &&
+	    *interface != 'D') {
+		errx(1, "Invalid interface '%c'", *interface);
+	}
+	ftdi_gpio->ftdi_interface = *interface - 'A';
+
+	c = strchr(interface, ';');
+
+	// GPIOs
+	while(c) {
+		char *name, *off, *pol;
+		unsigned gpio_type;
+		unsigned gpio_offset;
+		unsigned gpio_polarity;
+
+		name = c + 1;
+		off = strchr(name, ',');
+		if (!off)
+			errx(1, "GPIOs config invalid");
+		off += 1;
+		pol = strchr(off, ',');
+		if (!pol)
+			errx(1, "GPIOs config invalid");
+		pol += 1;
+
+		c = strchr(pol, ';');
+
+		if (strncmp("POWER", name, off - name - 1) == 0)
+			gpio_type = GPIO_POWER;
+		else if (strncmp("FASTBOOT_KEY", name, off - name - 1) == 0)
+			gpio_type = GPIO_FASTBOOT_KEY;
+		else if (strncmp("POWER_KEY", name, off - name - 1) == 0)
+			gpio_type = GPIO_POWER_KEY;
+		else if (strncmp("USB_DISCONNECT", name, off - name - 1) == 0)
+			gpio_type = GPIO_USB_DISCONNECT;
+		else
+			errx(1, "GPIOs type invalid: '%s'", name);
+
+		gpio_offset = strtoul(off, NULL, 0);
+		if (gpio_offset > 7)
+			errx(1, "GPIOs offset invalid: '%d'", gpio_offset);
+
+		if (strncmp("ACTIVE_HIGH", pol, c - pol - 1) == 0)
+			gpio_polarity = GPIO_ACTIVE_HIGH;
+		else if (strncmp("ACTIVE_LOW", pol, c - pol - 1) == 0)
+			gpio_polarity = GPIO_ACTIVE_LOW;
+		else
+			errx(1, "GPIOs polarity invalid: '%s'", pol);
+
+		ftdi_gpio->gpio_present[gpio_type] = 1;
+		ftdi_gpio->gpio_offset[gpio_type] = gpio_offset;
+		ftdi_gpio->gpio_polarity[gpio_type] = gpio_polarity;
+	}
+}
+
+void *ftdi_gpio_open(struct device *dev)
+{
+	struct ftdi_gpio *ftdi_gpio;
+	int ret;
+
+	ftdi_gpio = calloc(1, sizeof(*ftdi_gpio));
+
+	ftdi_gpio_parse_config(ftdi_gpio, dev->control_dev);
+
+	if ((ftdi_gpio->gpio = ftdi_new()) == 0)
+		errx(1, "failed to allocate ftdi gpio struct");
+
+	ftdi_set_interface(ftdi_gpio->gpio, INTERFACE_A + ftdi_gpio->ftdi_interface);
+
+	ret = ftdi_usb_open_string(ftdi_gpio->gpio, ftdi_gpio->ftdi_device);
+	if (ret < 0)
+		errx(1, "failed to open ftdi gpio device '%s' (%d)", ftdi_gpio->ftdi_device, ret);
+
+	ftdi_set_bitmode(ftdi_gpio->gpio, 0xFF, BITMODE_BITBANG);
+
+	if (ftdi_gpio->gpio_present[GPIO_POWER_KEY])
+		dev->has_power_key = true;
+
+	ftdi_gpio_device_power(ftdi_gpio, 0);
+
+	if (dev->usb_always_on)
+		ftdi_gpio_device_usb(ftdi_gpio, 1);
+	else
+		ftdi_gpio_device_usb(ftdi_gpio, 0);
+
+	usleep(500000);
+
+	return ftdi_gpio;
+}
+
+static int ftdi_gpio_toggle_io(struct ftdi_gpio *ftdi_gpio, unsigned int gpio, bool on)
+{
+	unsigned int bit;
+
+	if (!ftdi_gpio->gpio_present[gpio])
+		return -EINVAL;
+
+	bit = ftdi_gpio->gpio_offset[gpio];
+
+	if (ftdi_gpio->gpio_polarity[gpio])
+		on = !on;
+
+	if (on)
+		ftdi_gpio->gpio_lines |= (1 << bit);
+	else
+		ftdi_gpio->gpio_lines &= ~(1 << bit);
+
+	return ftdi_write_data(ftdi_gpio->gpio, &ftdi_gpio->gpio_lines, 1);
+}
+
+static int ftdi_gpio_device_power(struct ftdi_gpio *ftdi_gpio, bool on)
+{
+	return ftdi_gpio_toggle_io(ftdi_gpio, GPIO_POWER, on);
+}
+
+static void ftdi_gpio_device_usb(struct ftdi_gpio *ftdi_gpio, bool on)
+{
+	ftdi_gpio_toggle_io(ftdi_gpio, GPIO_USB_DISCONNECT, on);
+}
+
+int ftdi_gpio_power(struct device *dev, bool on)
+{
+	struct ftdi_gpio *ftdi_gpio = dev->cdb;
+
+	return ftdi_gpio_device_power(ftdi_gpio, on);
+}
+
+void ftdi_gpio_usb(struct device *dev, bool on)
+{
+	struct ftdi_gpio *ftdi_gpio = dev->cdb;
+
+	ftdi_gpio_device_usb(ftdi_gpio, on);
+}
+
+void ftdi_gpio_key(struct device *dev, int key, bool asserted)
+{
+	struct ftdi_gpio *ftdi_gpio = dev->cdb;
+
+	switch (key) {
+	case DEVICE_KEY_FASTBOOT:
+		ftdi_gpio_toggle_io(ftdi_gpio, GPIO_FASTBOOT_KEY, asserted);
+		break;
+	case DEVICE_KEY_POWER:
+		ftdi_gpio_toggle_io(ftdi_gpio, GPIO_POWER_KEY, asserted);
+		break;
+	}
+}

ftdi-gpio.h

@@ -0,0 +1,13 @@
+#ifndef __FTDI_GPIO_H__
+#define __FTDI_GPIO_H__
+
+#include "device.h"
+
+struct ftdi_gpio;
+
+void *ftdi_gpio_open(struct device *dev);
+int ftdi_gpio_power(struct device *dev, bool on);
+void ftdi_gpio_usb(struct device *dev, bool on);
+void ftdi_gpio_key(struct device *dev, int key, bool on);
+
+#endif