Initial commit, adding GPIO pins and callback functions for pin controll work

Makefile

@@ -0,0 +1,20 @@
+modname := usb_gpio
+obj-m := $(modname).o
+
+DEFINES := -DDEBUG
+ccflags-y= $(DEFINES) 
+
+KVERSION := $(shell uname -r)
+KDIR := /lib/modules/$(KVERSION)/build
+PWD := "$$(pwd)"
+
+default:
+	$(MAKE) -C $(KDIR) M=$(PWD) modules
+
+clean:
+	$(MAKE) -C $(KDIR) M=$(PWD) clean
+	rm -rf *~
+
+load:
+	-/sbin/rmmod $(modname)
+	/sbin/insmod $(modname).ko

gpio_callbacks.c

@@ -0,0 +1,20 @@
+
+static int get_value(struct gpio_chip *gc, unsigned offset){
+	DEBUG_OUT("<1>%s: GET_VALUE of pin%d ",MOD_NAME,offset);
+	return 0;
+}
+
+static void set_value(struct gpio_chip *chip, unsigned offset, int value){
+	DEBUG_OUT("<1>%s: SET_VALUE of pin%d to %d",MOD_NAME,offset,value);
+}
+
+static int set_in(struct gpio_chip *chip, unsigned offset){
+	DEBUG_OUT("<1>%s: SET_INPUT of pin%d ",MOD_NAME,offset);
+	return 0;
+}
+
+static int set_out(struct gpio_chip *chip, unsigned offset, int value){
+	DEBUG_OUT("<1>%s: SET_OUTPUT of pin%d to %d",MOD_NAME,offset,value);
+	return 0;
+}
+

pygpio.py

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+#!/usr/bin/python
+
+import os,sys
+
+NL='\n'
+
+class GPIO:
+	EXPORT = '/sys/class/gpio/export'
+	UNEXPORT = '/sys/class/gpio/unexport'
+	EFILE = None
+	IN = 1
+	OUT = 0
+	## The constructor
+	# @param num The kernel id number of the GPIO pin 
+	def __init__(self,num):
+		# type checks
+		if type(num)!=int:
+			raise ValueError('num should be int')
+		
+		# assignments
+		self.num=num		
+
+		# Try to open the gio control file
+		if GPIO.EFILE==None:
+			if !os.path.exists(GPIO.EXPORT):
+				raise IOError('file "'+GPIO.EXPORT+'" does not exist')
+			GPIO.EFILE=open(EXPORT,'wb')
+
+		# enable GPIO pin
+		EFILE.write(str(num)+NL)
+		
+		self.path = '/sys/class/gpio/gpio' + str(num)
+		
+		if !os.path.exists(self.path):
+				raise IOError('directory "'+self.path+'" does not exist')
+
+		# open the GPIOs value files
+		# as the directory was created I imply all of them exist
+		self.valuef = open(self.path+'/value','rwb')
+		self.directionf = open(self.path+'/direction','wb')
+		self.active_lowf = open( +'/active_low',,'wb')
+		self.edgef = open(self.path+'/edge',,'wb')
+
+		set_direction(GPIO.IN)
+		self.value = False
+		
+	def _read_value(self):
+		tmp=self.valuef.read()
+		self.value = tmp=="1"
+
+	def write_value(self,v):
+		if self.direction != GPIO.OUT:
+			return
+		self.value = not(v==0)
+		if self.value==0:
+			self.valuef.write('0')
+		elif self.value==1:
+			self.valuef.write('1')
+		else:
+			assert 0
+
+	def is_high(self):
+		if self.direction != GPIO.IN:
+			return False
+		self._read_value()
+		return self.value
+
+	def set_direction(self,d):
+		if d==GPIO.IN:
+			self.directionf.write('in'+NL)
+			self.direction=GPIO.IN
+		elif d==GPIO.OUT:
+			self.directionf.write('out'+NL)
+			self.direction=GPIO.OUT
+
+	## the destructor
+	def __del__(self):
+		if GPIO.EFILE!=None:
+			# free GPIO pin
+			# as the export path exists I imply unexport will also exist
+			tmpf = open(GPIO.UNEXPORT,'wb')
+			tmpf.write(str(self.num)+NL)
+			tmpf.close()
+			GPIO.EFILE.close()
+
+			self.valuef.close()
+			self.directionf.close()
+			self.active_lowf.close()
+			self.edgef.close()
+

usb_gpio.c

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+#include "usb_gpio.h"
+
+static struct gpio_chip ft232_chip;
+
+#include "gpio_callbacks.c"
+
+static void usb_gpio_exit(void) {
+	gpiochip_remove(&ft232_chip);
+	printk("<1>%s: Bye!\n",MOD_NAME);
+}
+
+static int usb_gpio_init(void) {
+	int ret;
+
+	printk("<1>%s: Loading... \n",MOD_NAME);
+	
+	ft232_chip.label = MOD_NAME;
+
+	//Callback functions
+	ft232_chip.direction_input = set_in;
+	ft232_chip.direction_output = set_out;
+	ft232_chip.get = get_value;
+	ft232_chip.set = set_value;
+
+	//Automaticaly choose GPIO numbers - manual seems not to be possible
+	ft232_chip.base = -1; 
+	//Number of GPIO pins
+	ft232_chip.ngpio = NUM_OF_GPIO;
+	 //This indicates that get and set functions can sleep
+	ft232_chip.can_sleep = 1;
+	ft232_chip.owner = THIS_MODULE;
+
+	ret = gpiochip_add(&ft232_chip);
+	DEBUG_OUT("<1>%s: gpiochip_add returned %d\n",MOD_NAME,ret);
+	if (ret){
+		printk("<1>%s: Can't register chip!\n",MOD_NAME);
+	}
+	return ret;
+}
+
+module_init(usb_gpio_init);
+module_exit(usb_gpio_exit);
+MODULE_LICENSE("Dual BSD/GPL");

usb_gpio.h

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+
+#ifndef _USB_GPIO_H
+#define _USB_GPIO_H
+
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/kernel.h> 
+#include <linux/slab.h> /* kmalloc() */
+#include <linux/gpio.h>
+
+
+#include "usb_gpio_util.h"
+
+#define NUM_OF_GPIO 8
+#define MOD_NAME "usb_gpio"
+
+#ifndef CONFIG_GENERIC_GPIO
+#error This module needs generic gpio support (CONFIG_GENERIC_GPIO)
+#endif
+
+#endif //_USB_GPIO_H

usb_gpio_util.h

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+
+#ifndef _USB_GPIO_UTIL
+#define _USB_GPIO_UTIL
+
+#ifdef DEBUG
+	#define DEBUG_OUT(FMT,...) printk(FMT, ## __VA_ARGS__)
+#else
+	#define DEBUG_OUT(FMT,...) {}
+#endif
+
+#endif //_USB_GPIO_UTIL