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FTDI_kernel_space_gpio_driver
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Will use message queues for IPC between the kernel and user-space helper

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master
Stefan Krulj 14 years ago
parent 4c5e1b78d2
commit ee18e4dfa5
5 changed files with 130 additions and 41 deletions
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  1. 4
      Makefile.helper
  2. 138
      ftdi_daemon.c
  3. 12
      ftdi_daemon.h
  4. 11
      usb_gpio.c
  5. 4
      usb_gpio.h

4
Makefile.helper
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@ -1,8 +1,8 @@
OBJS = ftdi_daemon.o
CC=gcc
CFLAGS =
DEFINES := -DDEBUG
CFLAGS = $(DEFINES)
LDFLAGS = -lftdi
usbgpiod: $(OBJS)

138
ftdi_daemon.c
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@ -10,8 +10,6 @@ volatile uint8_t main_loop=1;
static int vendor=0x0403, device=0x6001;
static int is_output(unsigned offset){
return !!((USB_GPIO_DDR)&(1<<offset));
}
@ -20,88 +18,158 @@ static int is_high(unsigned offset){
return !!((USB_GPIO_PORT)&(1<<offset));
}
/*!
This will update the data direction according to the current
USB_GPIO_DDR value
*/
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));
LOG("%s: %s\n",MOD_NAME,ftdi_get_error_string(&ftdic));
return -EIO;
}
return 0;
}
/*!
If in output this will allways return 0
in input it will return the logic level of the pin
*/
static int get_value(unsigned offset){
DEBUG_OUT("%s: GET_VALUE of pin%d ",MOD_NAME,offset);
DEBUG_OUT("%s: GET_VALUE of pin%d\n",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);
}
if( ftdi_read_pins(&ftdic,&USB_GPIO_PIN) < 0){
LOG("%s: Unable to read pin%d \n",MOD_NAME,offset);
}
return !!((USB_GPIO_PIN) & (1<<offset));
}
return 0;
}
/*!
If in input this will turn on/off the pullup
in output it will simply turn on/off the logic level of the pin
*/
static void set_value(unsigned offset, int value){
DEBUG_OUT("%s: SET_VALUE of pin%d to %d",MOD_NAME,offset,value);
DEBUG_OUT("%s: SET_VALUE of pin%d to %d\n",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);
}
}
if(value){
USB_GPIO_PORT |= (1<<offset);
}else{
USB_GPIO_PORT &= ~(1<<offset);
}
if( ftdi_write_data(&ftdic,&USB_GPIO_PORT,1) < 0){
LOG("%s: Unable to set pin%d to value %d\n",MOD_NAME,offset,value);
}
}
/*!
This will set the pin as input.
Warning: if the pin is HIGH at the moment you put the pin to input
the pull-up of that pin will be enabled
*/
static int set_in(unsigned offset){
DEBUG_OUT("%s: SET_INPUT of pin%d ",MOD_NAME,offset);
DEBUG_OUT("%s: SET_INPUT of pin%d\n",MOD_NAME,offset);
USB_GPIO_DDR &= ~(1<<offset);
return update_mode();
}
/*
This will set the pin as output and drive its logic level according
to value.
*/
static int set_out(unsigned offset, int value){
DEBUG_OUT("%s: SET_OUTPUT of pin%d to %d",MOD_NAME,offset,value);
DEBUG_OUT("%s: SET_OUTPUT of pin%d to %d\n",MOD_NAME,offset,value);
USB_GPIO_DDR |= (1<<offset);
set_value(offset,value);
return update_mode();
}
static int ftdi_chip_init(){
// Init FTDI lib
// Init FTDI lib
DEBUG_OUT("INIT libftdi\n");
if( ftdi_init(&ftdic)<0 ){
printf("%s: Can't initialize FTDI-lib!\n",MOD_NAME);
LOG("%s: Can't initialize FTDI-lib!\n",MOD_NAME);
return ENOMEM;
}
// Open device
DEBUG_OUT("Opening device (%04x:%04x) \n",vendor,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));
LOG("%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;
// Put device into bitbang mode
DEBUG_OUT("Putting device (%04x:%04x) into bitbang mode\n",vendor,device);
if( ftdi_set_bitmode(&ftdic, 0x00, BITMODE_BITBANG)<0 ){
printf("%s: Can't enter FTDIs bitbang mode (%04x:%04x)!\n",MOD_NAME,vendor,device);
LOG("%s: %s\n",MOD_NAME,ftdi_get_error_string(&ftdic));
return EIO;
}
// Set all pins low
if( ftdi_write_data(&ftdic,&USB_GPIO_PORT,1) < 0){
LOG("%s: Unable to set pins to low\n",MOD_NAME);
return EIO;
}
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);
LOG("%s: Can't reset FTDI (%04x:%04x)!\n",MOD_NAME,vendor,device);
}
if( ftdi_usb_close(&ftdic) < 0){
LOG("%s: Unable to close FTDI-Device!\n",MOD_NAME);
LOG("%s: %s\n",MOD_NAME,ftdi_get_error_string(&ftdic));
}
ftdi_deinit(&ftdic);
}
enum cmd_states {CMD_PORT_NUM, CMD_CMD};
static int cmd_fsm(char c){
static int state = CMD_PORT_NUM;
static char pin = 0;
int ret;
switch(state){
case CMD_PORT_NUM:
pin=c;
state=CMD_CMD;
break;
case CMD_CMD:
state = CMD_PORT_NUM;
// Pin commands
switch(c){
case CMD_IN:
return set_in((unsigned)pin);
case CMD_OUTH:
return set_out((unsigned)pin,1);
case CMD_OUTL:
return set_out((unsigned)pin,0);
case CMD_H:
set_value((unsigned)pin,1);
return 0;
case CMD_L:
set_value((unsigned)pin,0);
return 0;
case CMD_READ:
ret = get_value((unsigned)pin);
DEBUG_OUT("Value of %d is %d\n", pin,ret);
fputc((char)ret,stdout);
return 0;
}
}
return 0;
}
int main(void){
@ -111,7 +179,13 @@ int main(void){
}
for(;main_loop;){
//Sleep mostly
//kernel will write commands to the stdin
ret = fgetc(stdin);
if( ret!=EOF ){
cmd_fsm(ret);
}else{
//main_loop=0;
}
}
ftdi_chip_exit();

12
ftdi_daemon.h
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@ -1,19 +1,27 @@
#ifndef _FTDL_DAEMON_H
#define _FTDL_DAEMON_H
#include <sys/msg.h>
#include <ftdi.h>
#include <stdio.h>
#include <stdint.h>
#include <errno.h>
#define MOD_NAME "usb_gpio"
#include "common.h"
#ifdef DEBUG
#define DEBUG_OUT(FMT,...) printk(FMT, ## __VA_ARGS__)
#define DEBUG_OUT(FMT,...) printf(FMT, ## __VA_ARGS__)
#else
#define DEBUG_OUT(FMT,...) {}
#endif
#ifdef DEBUG
#define LOG(FMT,...) printf(FMT, ## __VA_ARGS__)
#else
#define DEBUG_OUT(FMT,...) {} //FIXME: add a log-file
#endif
#define PIN_TX 0
#define PIX_RX 1
#define PIN_RTS 2

11
usb_gpio.c
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@ -1,6 +1,7 @@
#include "usb_gpio.h"
static struct gpio_chip ft232_chip;
static struct subprocess_info *sub_info;
#include "gpio_callbacks.c"
@ -14,7 +15,7 @@ static void usb_gpio_exit(void) {
static int usb_gpio_init(void) {
int ret;
// Prepare user space handler call
char *argv[] = { "/usr/bin/logger", "help!", NULL };
char *argv[] = { "/usr/bin/usb_gpio_ftdi_helper", NULL };
static char *envp[] = {
"HOME=/",
"TERM=linux",
@ -45,7 +46,13 @@ static int usb_gpio_init(void) {
}
//Call the user space handler
return call_usermodehelper( argv[0], argv, envp, UMH_WAIT_PROC );
sub_info = call_usermodehelper_setup( argv[0], argv, envp, GFP_ATOMIC );
if (sub_info == NULL){
return -ENOMEM;
}
// the helper will run in the background until the module decides to kill it
return call_usermodehelper_exec( sub_info, UMH_NO_WAIT );
}
module_init(usb_gpio_init);

4
usb_gpio.h
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@ -9,12 +9,12 @@
#include <linux/slab.h> /* kmalloc() */
#include <linux/gpio.h>
#include <linux/kmod.h>
#include <linux/msg.h>
#include "usb_gpio_util.h"
#include "common.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)

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