pl2303.c

   1 #include <stdio.h>
   2 #include <stdlib.h>
   3 /* According to POSIX.1-2001 */
   4 #include <sys/select.h>
   5 #include <string.h>
   6 #include <sys/time.h>
   7 #include <sys/types.h>
   8 #include <unistd.h>
   9 #include <termios.h>
  10 #include <fcntl.h>
  11 #include <signal.h>
  12 #include <libusb.h>
  13 #include <getopt.h>
  14
  15
  16 #define _GNU_SOURCE
  17 #include <getopt.h>
  18
  19
  20 #define I_VENDOR_NUM        0x67b
  21 #define I_PRODUCT_NUM       0x2303
  22
  23
  24 #define VENDOR_READ_REQUEST_TYPE        0xc0
  25 #define VENDOR_READ_REQUEST             0x01
  26
  27 #define VENDOR_WRITE_REQUEST_TYPE       0x40
  28 #define VENDOR_WRITE_REQUEST            0x01
  29
  30
  31 int get_device_vid()
  32 {
  33         return I_VENDOR_NUM;
  34 }
  35
  36 int get_device_pid()
  37 {
  38         return I_PRODUCT_NUM;
  39 }
  40
  41 /* Get current GPIO register from PL2303 */
  42 char gpio_read_reg(libusb_device_handle *h)
  43 {
  44         char buf;
  45         int bytes = libusb_control_transfer(
  46                 h,             // handle obtained with usb_open()
  47                 VENDOR_READ_REQUEST_TYPE, // bRequestType
  48                 VENDOR_READ_REQUEST,      // bRequest
  49                 0x0081,              // wValue
  50                 0,              // wIndex
  51                 &buf,             // pointer to destination buffer
  52                 1,  // wLength
  53                 100
  54                 );
  55         handle_error(bytes);
  56         return buf;
  57 }
  58
  59 void gpio_write_reg(libusb_device_handle *h, unsigned char reg)
  60 {
  61         int bytes = libusb_control_transfer(
  62                 h,             // handle obtained with usb_open()
  63                 VENDOR_WRITE_REQUEST_TYPE, // bRequestType
  64                 VENDOR_WRITE_REQUEST,      // bRequest
  65                 1,              // wValue
  66                 reg,              // wIndex
  67                 0,             // pointer to destination buffer
  68                 0,  // wLength
  69                 6000
  70                 );
  71         handle_error(bytes);
  72
  73 }
  74
  75 int gpio_dir_shift(int gpio) {
  76         if (gpio == 0)
  77                 return 4;
  78         if (gpio == 1)
  79                 return 5;
  80         return 4; /* default to 0 */
  81 }
  82
  83 int gpio_val_shift(int gpio) {
  84         if (gpio == 0)
  85                 return 6;
  86         if (gpio == 1)
  87                 return 7;
  88         return 6; /* default to 0 */
  89 }
  90
  91
  92 void gpio_out(libusb_device_handle *h, int gpio, int value)
  93 {
  94         int shift_dir = gpio_dir_shift(gpio);
  95         int shift_val = gpio_val_shift(gpio);
  96         unsigned char reg = gpio_read_reg(h);
  97         reg |= (1 << shift_dir);
  98         reg &= ~(1 << shift_val);
  99         reg |= (value << shift_val);
 100         gpio_write_reg(h, reg);
 101 }
 102
 103 void gpio_in(libusb_device_handle *h, int gpio, int pullup)
 104 {
 105         int shift_dir = gpio_dir_shift(gpio);
 106         int shift_val = gpio_val_shift(gpio);
 107
 108         unsigned char reg = gpio_read_reg(h);
 109         reg &= ~(1 << shift_dir);
 110         reg &= ~(1 << shift_val);
 111         reg |= (pullup << shift_val);
 112         gpio_write_reg(h, reg);
 113 }
 114
 115 int gpio_read(libusb_device_handle *h, int gpio)
 116 {
 117         unsigned char r = gpio_read_reg(h);
 118         int shift = gpio_val_shift(gpio);
 119         return (r & (1<<shift));
 120 }
 121