Driver concept changed to use a user-space helper app

Makefile

@@ -2,9 +2,11 @@ modname := usb_gpio
 obj-m := $(modname).o
 
 DEFINES := -DDEBUG
-ccflags-y= $(DEFINES) 
+ccflags-y= $(DEFINES) -I/usr/include/
 
 KVERSION := $(shell uname -r)
+KMACHINE := $(shell uname -m)
+
 KDIR := /lib/modules/$(KVERSION)/build
 PWD := "$$(pwd)"
 
@@ -13,8 +15,13 @@ default:
 
 clean:
 	$(MAKE) -C $(KDIR) M=$(PWD) clean
+	$(MAKE) -f Makefile.helper clean
 	rm -rf *~
 
 load:
 	-/sbin/rmmod $(modname)
 	/sbin/insmod $(modname).ko
+
+helper:
+	$(MAKE) -f Makefile.helper
+	

Makefile.helper

@@ -0,0 +1,16 @@
+
+OBJS = ftdi_daemon.o
+
+CC=gcc
+CFLAGS = 
+LDFLAGS = -lftdi
+
+usbgpiod: $(OBJS)
+	$(CC) $(CFLAGS) $(LDFLAGS) -o $@ $<
+
+%.o:	%.c
+	$(CC) $(CFLAGS) -Wa,-a=$*.list -c -o $@ $<
+
+clean:
+	rm -rf $(OBJS) usbgpiod
+	rm -rf *.list *~

ftdi_daemon.c

@@ -0,0 +1,120 @@
+#include "ftdi_daemon.h"
+
+struct ftdi_context ftdic;
+
+uint8_t USB_GPIO_DDR;
+uint8_t USB_GPIO_PORT;
+uint8_t USB_GPIO_PIN;
+
+volatile uint8_t main_loop=1;
+
+static int vendor=0x0403, device=0x6001;
+
+
+
+static int is_output(unsigned offset){
+	return !!((USB_GPIO_DDR)&(1<<offset));
+}
+
+static int is_high(unsigned offset){
+	return !!((USB_GPIO_PORT)&(1<<offset));
+}
+
+static int update_mode(void){
+	if( ftdi_set_bitmode(&ftdic, USB_GPIO_DDR, BITMODE_BITBANG)<0 ){
+        printf("%s: Can't enter FTDIs bitbang mode (%04x:%04x)!\n",MOD_NAME,vendor,device);
+		printf("%s: %s\n",MOD_NAME,ftdi_get_error_string(&ftdic));
+        return -EIO;
+	}
+	return 0;
+}
+
+static int get_value(unsigned offset){
+	DEBUG_OUT("%s: GET_VALUE of pin%d ",MOD_NAME,offset);
+	if( !is_output(offset) ){
+		while( ftdic.readbuffer_remaining > 0 ){
+			if( ftdi_read_data(&ftdic,&USB_GPIO_PIN,1) < 0){
+				printf("%s: Unable to read pin%d \n",MOD_NAME,offset);
+			}
+		}
+		return !!((USB_GPIO_PIN) & (1<<offset));
+	}
+	return 0;
+}
+static void set_value(unsigned offset, int value){
+	DEBUG_OUT("%s: SET_VALUE of pin%d to %d",MOD_NAME,offset,value);
+
+	if( !is_output(offset) ){
+		if(value && !is_high(offset)){
+			if( ftdi_write_data(&ftdic,&USB_GPIO_PORT,1) < 0){
+				printf("%s: Unable to set pin%d to value %d\n",MOD_NAME,offset,value);
+			}
+		}else if(!value && is_high(offset)){
+			if( ftdi_write_data(&ftdic,&USB_GPIO_PORT,1) < 0){
+				printf("%s: Unable to set pin%d to value %d\n",MOD_NAME,offset,value);
+			}
+		}
+	}
+}
+
+static int set_in(unsigned offset){
+	DEBUG_OUT("%s: SET_INPUT of pin%d ",MOD_NAME,offset);
+
+	USB_GPIO_DDR &= ~(1<<offset); 
+	return update_mode();
+}
+static int set_out(unsigned offset, int value){
+	DEBUG_OUT("%s: SET_OUTPUT of pin%d to %d",MOD_NAME,offset,value);
+
+	USB_GPIO_DDR |= (1<<offset); 
+	return update_mode();
+}
+
+static int ftdi_chip_init(){
+		// Init FTDI lib
+	if( ftdi_init(&ftdic)<0 ){
+		printf("%s: Can't initialize FTDI-lib!\n",MOD_NAME);
+		return ENOMEM;
+	}
+
+	// Open device
+	if(ftdi_usb_open(&ftdic, vendor, device)<0) {
+        printf("%s: Can't open FTDI chip (%04x:%04x)!\n",MOD_NAME,vendor,device);
+		printf("%s: %s\n",MOD_NAME,ftdi_get_error_string(&ftdic));
+        return ENXIO;
+    }
+	// Put device into bitbang modes
+	if( ftdi_set_bitmode(&ftdic, 0x00, BITMODE_BITBANG)<0 ){
+        printf("%s: Can't enter FTDIs bitbang mode (%04x:%04x)!\n",MOD_NAME,vendor,device);
+		printf("%s: %s\n",MOD_NAME,ftdi_get_error_string(&ftdic));
+        return EIO;
+	}
+
+	//All pins input
+	USB_GPIO_DDR  = 0x00;
+	//No port set
+	USB_GPIO_PORT = 0x00;
+	
+	return 0;
+}
+
+static void ftdi_chip_exit(){
+	if( ftdi_disable_bitbang(&ftdic)<0 ){
+		printf("%s: Can't reset FTDI (%04x:%04x)!\n",MOD_NAME,vendor,device);
+	}
+}
+
+int main(void){
+	int ret=ftdi_chip_init();
+	if(ret!=0){
+		return ret;
+	}
+
+	for(;main_loop;){
+		//Sleep mostly
+	}
+
+	ftdi_chip_exit();
+	return 0;
+}
+

ftdi_daemon.h

@@ -0,0 +1,35 @@
+#ifndef _FTDL_DAEMON_H
+#define _FTDL_DAEMON_H
+
+#include <ftdi.h>
+#include <stdio.h>
+#include <stdint.h>
+#include <errno.h>
+
+#define MOD_NAME "usb_gpio"
+
+#ifdef DEBUG
+	#define DEBUG_OUT(FMT,...) printk(FMT, ## __VA_ARGS__)
+#else
+	#define DEBUG_OUT(FMT,...) {}
+#endif
+
+#define PIN_TX  0
+#define PIX_RX  1
+#define PIN_RTS 2
+#define PIN_CTS 3
+#define PIN_DTR 4
+#define PIN_DSR 5
+#define PIN_DCD 6
+#define PIN_RI  7
+
+#define PIN_0  0
+#define PIN_1  1
+#define PIN_2  2
+#define PIN_3  3
+#define PIN_4  4
+#define PIN_5  5
+#define PIN_6  6
+#define PIN_7  7
+
+#endif //_FTDL_DAEMON_H

usb_gpio.c

@@ -5,12 +5,20 @@ static struct gpio_chip ft232_chip;
 #include "gpio_callbacks.c"
 
 static void usb_gpio_exit(void) {
-	gpiochip_remove(&ft232_chip);
+	if( gpiochip_remove(&ft232_chip)<0 ){
+		printk("<1>%s: Couldn't free GPIO-pins!\n",MOD_NAME);
+	}
 	printk("<1>%s: Bye!\n",MOD_NAME);
 }
 
 static int usb_gpio_init(void) {
 	int ret;
+	// Prepare user space handler call
+	char *argv[] = { "/usr/bin/logger", "help!", NULL };
+	static char *envp[] = {
+		"HOME=/",
+		"TERM=linux",
+		"PATH=/sbin:/bin:/usr/sbin:/usr/bin", NULL };
 
 	printk("<1>%s: Loading... \n",MOD_NAME);
 	
@@ -35,7 +43,9 @@ static int usb_gpio_init(void) {
 	if (ret){
 		printk("<1>%s: Can't register chip!\n",MOD_NAME);
 	}
-	return ret;
+	
+	//Call the user space handler
+	return call_usermodehelper( argv[0], argv, envp, UMH_WAIT_PROC );
 }
 
 module_init(usb_gpio_init);

usb_gpio.h

@@ -8,6 +8,7 @@
 #include <linux/kernel.h> 
 #include <linux/slab.h> /* kmalloc() */
 #include <linux/gpio.h>
+#include <linux/kmod.h>
 
 
 #include "usb_gpio_util.h"