Use const in PROGRAMMER function arguments where appropriate

In order to get meaningful const properties for the PROGRAMMER, AVRPART and
AVRMEM arguments, some code needed to be moved around, otherwise a network of
"tainted" assignments risked rendering nothing const:

 - Change void (*enable)(PROGRAMMER *pgm) to void (*enable)(PROGRAMMER *pgm,
   const AVRPART *p); this allows changes in the PROGRAMMER structure after
   the part is known. For example, use TPI, UPDI, PDI functions in that
   programmer appropriate to the part. This used to be done later in the
   process, eg, in the initialize() function, which "taints" all other
   programmer functions wrt const and sometimes requires other finessing with
   flags etc. Much clearer with the modified enable() interface.

 - Move TPI initpgm-type code from initialize() to enable() --- note that
   initpgm() does not have the info at the time when it is called whether or
   not TPI is required

 - buspirate.c: move pgm->flag to PDATA(pgm)->flag (so legitimate
   modification of the flag does not change PROGRAMMER structure)

 - Move AVRPART_INIT_SMC and AVRPART_WRITE bits from the flags field in
   AVRPART to jtagmkII.c's private data flags32 fiels as FLAGS32_INIT_SMC and
   FLAGS32_WRITE bits

 - Move the xbeeResetPin component to private data in stk500.c as this is
   needed by xbee when it saddles on the stk500 code (previously, the flags
   component of the part was re-dedicated to this)

 - Change the way the "chained" private data are used in jtag3.c whilst
   keeping the PROGRAMMER structure read-only otherwise

 - In stk500v2.c move the STK600 pgm update from stk500v2_initialize() to
   stk500v2_enable() so the former keeps the PROGRAMMER structure read-only
   (for const assertion).

 - In usbasp change the code from changing PROGRAMMER functions late to
   dispatching to TPI or regular SPI protocol functions at runtime; reason
   being the decision whether to use TPI protocol is done at run-time
   depending on the capability of the attached programmer

Also fixes Issue #1071, the treatment of default eecr value.

src/usbasp.c

@@ -154,9 +154,9 @@ struct pdata
 // interface - management
 static void usbasp_setup(PROGRAMMER * pgm);
 static void usbasp_teardown(PROGRAMMER * pgm);
-static int usbasp_parseextparms(PROGRAMMER * pgm, LISTID extparms);
+static int usbasp_parseextparms(const PROGRAMMER *pgm, const LISTID extparms);
 // internal functions
-static int usbasp_transmit(PROGRAMMER * pgm, unsigned char receive,
+static int usbasp_transmit(const PROGRAMMER *pgm, unsigned char receive,
 			   unsigned char functionid, const unsigned char *send,
 			   unsigned char *buffer, int buffersize);
 #ifdef USE_LIBUSB_1_0
@@ -165,39 +165,98 @@ static int usbOpenDevice(libusb_device_handle **device, int vendor, const char *
 static int usbOpenDevice(usb_dev_handle **device, int vendor, const char *vendorName, int product, const char *productName);
 #endif
 // interface - prog.
-static int usbasp_open(PROGRAMMER * pgm, char * port);
-static void usbasp_close(PROGRAMMER * pgm);
+static int usbasp_open(PROGRAMMER *pgm, const char *port);
+static void usbasp_close(PROGRAMMER *pgm);
 // dummy functions
-static void usbasp_disable(PROGRAMMER * pgm);
-static void usbasp_enable(PROGRAMMER * pgm);
-static void usbasp_display(PROGRAMMER * pgm, const char * p);
+static void usbasp_disable(const PROGRAMMER *pgm);
+static void usbasp_enable(PROGRAMMER *pgm, const AVRPART *p);
+static void usbasp_display(const PROGRAMMER *pgm, const char *p);
 // universal functions
-static int usbasp_initialize(PROGRAMMER * pgm, AVRPART * p);
+static int usbasp_initialize(const PROGRAMMER *pgm, const AVRPART *p);
 // SPI specific functions
-static int usbasp_spi_cmd(PROGRAMMER * pgm, const unsigned char *cmd, unsigned char *res);
-static int usbasp_spi_program_enable(PROGRAMMER * pgm, AVRPART * p);
-static int usbasp_spi_chip_erase(PROGRAMMER * pgm, AVRPART * p);
-static int usbasp_spi_paged_load(PROGRAMMER * pgm, AVRPART * p, AVRMEM * m,
+static int usbasp_spi_cmd(const PROGRAMMER *pgm, const unsigned char *cmd, unsigned char *res);
+static int usbasp_spi_program_enable(const PROGRAMMER *pgm, const AVRPART *p);
+static int usbasp_spi_chip_erase(const PROGRAMMER *pgm, const AVRPART *p);
+static int usbasp_spi_paged_load(const PROGRAMMER *pgm, const AVRPART *p, const AVRMEM *m,
                                  unsigned int page_size,
                                  unsigned int addr, unsigned int n_bytes);
-static int usbasp_spi_paged_write(PROGRAMMER * pgm, AVRPART * p, AVRMEM * m,
+static int usbasp_spi_paged_write(const PROGRAMMER *pgm, const AVRPART *p, const AVRMEM *m,
                                   unsigned int page_size,
                                   unsigned int addr, unsigned int n_bytes);
-static int usbasp_spi_set_sck_period(PROGRAMMER *pgm, double sckperiod);
+static int usbasp_spi_set_sck_period(const PROGRAMMER *pgm, double sckperiod);
 // TPI specific functions
-static void usbasp_tpi_send_byte(PROGRAMMER * pgm, uint8_t b);
-static int usbasp_tpi_cmd(PROGRAMMER * pgm, const unsigned char *cmd, unsigned char *res);
-static int usbasp_tpi_program_enable(PROGRAMMER * pgm, AVRPART * p);
-static int usbasp_tpi_chip_erase(PROGRAMMER * pgm, AVRPART * p);
-static int usbasp_tpi_paged_load(PROGRAMMER * pgm, AVRPART * p, AVRMEM * m,
+static void usbasp_tpi_send_byte(const PROGRAMMER *pgm, uint8_t b);
+static int usbasp_tpi_cmd(const PROGRAMMER *pgm, const unsigned char *cmd, unsigned char *res);
+static int usbasp_tpi_program_enable(const PROGRAMMER *pgm, const AVRPART *p);
+static int usbasp_tpi_chip_erase(const PROGRAMMER *pgm, const AVRPART *p);
+static int usbasp_tpi_paged_load(const PROGRAMMER *pgm, const AVRPART *p, const AVRMEM *m,
                                  unsigned int page_size,
                                  unsigned int addr, unsigned int n_bytes);
-static int usbasp_tpi_paged_write(PROGRAMMER * pgm, AVRPART * p, AVRMEM * m,
+static int usbasp_tpi_paged_write(const PROGRAMMER *pgm, const AVRPART *p, const AVRMEM *m,
                                   unsigned int page_size,
                                   unsigned int addr, unsigned int n_bytes);
-static int usbasp_tpi_set_sck_period(PROGRAMMER *pgm, double sckperiod);
-static int usbasp_tpi_read_byte(PROGRAMMER * pgm, AVRPART * p, AVRMEM * m, unsigned long addr, unsigned char * value);
-static int usbasp_tpi_write_byte(PROGRAMMER * pgm, AVRPART * p, AVRMEM * m, unsigned long addr, unsigned char data);
+static int usbasp_tpi_set_sck_period(const PROGRAMMER *pgm, double sckperiod);
+static int usbasp_tpi_read_byte(const PROGRAMMER * pgm, const AVRPART *p, const AVRMEM *m, unsigned long addr, unsigned char *value);
+static int usbasp_tpi_write_byte(const PROGRAMMER *pgm, const AVRPART *p, const AVRMEM *m, unsigned long addr, unsigned char data);
+
+
+// Dispatching wrappers
+
+static int usbasp_cmd(const PROGRAMMER *pgm, const unsigned char *cmd, unsigned char *res) {
+  return PDATA(pgm)->use_tpi?
+    usbasp_tpi_cmd(pgm, cmd, res):
+    usbasp_spi_cmd(pgm, cmd, res);
+}
+
+static int usbasp_program_enable(const PROGRAMMER *pgm, const AVRPART *p) {
+  return PDATA(pgm)->use_tpi?
+    usbasp_tpi_program_enable(pgm, p):
+    usbasp_spi_program_enable(pgm, p);
+}
+
+static int usbasp_chip_erase(const PROGRAMMER *pgm, const AVRPART *p) {
+  return PDATA(pgm)->use_tpi?
+    usbasp_tpi_chip_erase(pgm, p):
+    usbasp_spi_chip_erase(pgm, p);
+}
+
+static int usbasp_paged_load(const PROGRAMMER *pgm, const AVRPART *p, const AVRMEM *m,
+  unsigned int page_size, unsigned int addr, unsigned int n_bytes) {
+
+  return PDATA(pgm)->use_tpi?
+    usbasp_tpi_paged_load(pgm, p, m, page_size, addr, n_bytes):
+    usbasp_spi_paged_load(pgm, p, m, page_size, addr, n_bytes);
+}
+
+static int usbasp_paged_write(const PROGRAMMER *pgm, const AVRPART *p, const AVRMEM *m,
+  unsigned int page_size, unsigned int addr, unsigned int n_bytes) {
+
+  return PDATA(pgm)->use_tpi?
+    usbasp_tpi_paged_write(pgm, p, m, page_size, addr, n_bytes):
+    usbasp_spi_paged_write(pgm, p, m, page_size, addr, n_bytes);
+}
+
+static int usbasp_set_sck_period(const PROGRAMMER *pgm, double sckperiod) {
+  return PDATA(pgm)->use_tpi?
+    usbasp_tpi_set_sck_period(pgm, sckperiod):
+    usbasp_spi_set_sck_period(pgm, sckperiod);
+}
+
+static int usbasp_read_byte(const PROGRAMMER *pgm, const AVRPART *p, const AVRMEM *m,
+  unsigned long addr, unsigned char * value) {
+
+  return PDATA(pgm)->use_tpi?
+    usbasp_tpi_read_byte(pgm, p, m, addr, value):
+    avr_read_byte_default(pgm, p, m, addr, value);
+}
+
+static int usbasp_write_byte(const PROGRAMMER *pgm, const AVRPART *p, const AVRMEM *m,
+  unsigned long addr, unsigned char data) {
+
+  return PDATA(pgm)->use_tpi?
+    usbasp_tpi_write_byte(pgm, p, m, addr, data):
+    avr_write_byte_default(pgm, p, m, addr, data);
+}
 
 
 /* Interface - management */
@@ -216,8 +275,7 @@ static void usbasp_teardown(PROGRAMMER * pgm)
   free(pgm->cookie);
 }
 
-static int usbasp_parseextparms(PROGRAMMER * pgm, LISTID extparms)
-{
+static int usbasp_parseextparms(const PROGRAMMER *pgm, const LISTID extparms) {
   LNODEID ln;
   const char *extended_param;
   int rv = 0;
@@ -270,7 +328,7 @@ static const char *usbasp_get_funcname(unsigned char functionid)
 /*
  * wrapper for usb_control_msg call
  */
-static int usbasp_transmit(PROGRAMMER * pgm,
+static int usbasp_transmit(const PROGRAMMER *pgm,
 			   unsigned char receive, unsigned char functionid,
 			   const unsigned char *send,
 			   unsigned char *buffer, int buffersize)
@@ -491,8 +549,7 @@ static int           didUsbInit = 0;
 
 
 /* Interface - prog. */
-static int usbasp_open(PROGRAMMER * pgm, char * port)
-{
+static int usbasp_open(PROGRAMMER *pgm, const char *port) {
   avrdude_message(MSG_DEBUG, "%s: usbasp_open(\"%s\")\n",
 	    progname, port);
 
@@ -582,29 +639,28 @@ static void usbasp_close(PROGRAMMER * pgm)
 
 
 /* Dummy functions */
-static void usbasp_disable(PROGRAMMER * pgm)
-{
+static void usbasp_disable(const PROGRAMMER *pgm) {
   /* Do nothing. */
 
   return;
 }
 
-static void usbasp_enable(PROGRAMMER * pgm)
-{
+static void usbasp_enable(PROGRAMMER *pgm, const AVRPART *p) {
   /* Do nothing. */
 
   return;
 }
 
-static void usbasp_display(PROGRAMMER * pgm, const char * p)
-{
+static void usbasp_display(const PROGRAMMER *pgm, const char *p) {
   return;
 }
 
 
+
+// @@@
+
 /* Universal functions: for both SPI and TPI */
-static int usbasp_initialize(PROGRAMMER * pgm, AVRPART * p)
-{
+static int usbasp_initialize(const PROGRAMMER *pgm, const AVRPART *p) {
   unsigned char temp[4];
   unsigned char res[4];
   IMPORT_PDATA(pgm);
@@ -618,7 +674,7 @@ static int usbasp_initialize(PROGRAMMER * pgm, AVRPART * p)
   else
     pdata->capabilities = 0;
 
-  pdata->use_tpi = ((pdata->capabilities & USBASP_CAP_TPI) != 0 && (p->flags & AVRPART_HAS_TPI) != 0) ? 1 : 0;
+  pdata->use_tpi = (pdata->capabilities & USBASP_CAP_TPI) && (p->flags & AVRPART_HAS_TPI);
   // query support for 3 MHz SCK in UsbAsp-flash firmware
   // https://github.com/nofeletru/UsbAsp-flash
   pdata->sck_3mhz = ((pdata->capabilities & USBASP_CAP_3MHZ) != 0) ? 1 :0;
@@ -636,16 +692,6 @@ static int usbasp_initialize(PROGRAMMER * pgm, AVRPART * p)
 
     /* connect */
     usbasp_transmit(pgm, 1, USBASP_FUNC_TPI_CONNECT, temp, res, sizeof(res));
-    
-    /* change interface */
-    pgm->program_enable = usbasp_tpi_program_enable;
-    pgm->chip_erase     = usbasp_tpi_chip_erase;
-    pgm->cmd            = usbasp_tpi_cmd;
-    pgm->read_byte      = usbasp_tpi_read_byte;
-    pgm->write_byte     = usbasp_tpi_write_byte;
-    pgm->paged_write    = usbasp_tpi_paged_write;
-    pgm->paged_load     = usbasp_tpi_paged_load;
-    pgm->set_sck_period	= usbasp_tpi_set_sck_period;
   }
   else
   {
@@ -654,16 +700,6 @@ static int usbasp_initialize(PROGRAMMER * pgm, AVRPART * p)
 
     /* connect to target device */
     usbasp_transmit(pgm, 1, USBASP_FUNC_CONNECT, temp, res, sizeof(res));
-
-    /* change interface */
-    pgm->program_enable = usbasp_spi_program_enable;
-    pgm->chip_erase     = usbasp_spi_chip_erase;
-    pgm->cmd            = usbasp_spi_cmd;
-    pgm->read_byte      = avr_read_byte_default;
-    pgm->write_byte     = avr_write_byte_default;
-    pgm->paged_write    = usbasp_spi_paged_write;
-    pgm->paged_load     = usbasp_spi_paged_load;
-    pgm->set_sck_period	= usbasp_spi_set_sck_period;
   }
 
   /* wait, so device is ready to receive commands */
@@ -673,7 +709,7 @@ static int usbasp_initialize(PROGRAMMER * pgm, AVRPART * p)
 }
 
 /* SPI specific functions */
-static int usbasp_spi_cmd(PROGRAMMER * pgm, const unsigned char *cmd,
+static int usbasp_spi_cmd(const PROGRAMMER *pgm, const unsigned char *cmd,
                    unsigned char *res)
 {
   avrdude_message(MSG_DEBUG, "%s: usbasp_spi_cmd(0x%02x, 0x%02x, 0x%02x, 0x%02x)%s",
@@ -698,8 +734,7 @@ static int usbasp_spi_cmd(PROGRAMMER * pgm, const unsigned char *cmd,
   return 0;
 }
 
-static int usbasp_spi_program_enable(PROGRAMMER * pgm, AVRPART * p)
-{
+static int usbasp_spi_program_enable(const PROGRAMMER *pgm, const AVRPART *p) {
   unsigned char res[4];
   unsigned char cmd[4];
   memset(cmd, 0, sizeof(cmd));
@@ -722,8 +757,7 @@ static int usbasp_spi_program_enable(PROGRAMMER * pgm, AVRPART * p)
   return 0;
 }
 
-static int usbasp_spi_chip_erase(PROGRAMMER * pgm, AVRPART * p)
-{
+static int usbasp_spi_chip_erase(const PROGRAMMER *pgm, const AVRPART *p) {
   unsigned char cmd[4];
   unsigned char res[4];
 
@@ -746,10 +780,9 @@ static int usbasp_spi_chip_erase(PROGRAMMER * pgm, AVRPART * p)
   return 0;
 }
 
-static int usbasp_spi_paged_load(PROGRAMMER * pgm, AVRPART * p, AVRMEM * m,
-                                 unsigned int page_size,
-                                 unsigned int address, unsigned int n_bytes)
-{
+static int usbasp_spi_paged_load(const PROGRAMMER *pgm, const AVRPART *p, const AVRMEM *m,
+  unsigned int page_size, unsigned int address, unsigned int n_bytes) {
+
   int n;
   unsigned char cmd[4];
   int wbytes = n_bytes;
@@ -813,10 +846,9 @@ static int usbasp_spi_paged_load(PROGRAMMER * pgm, AVRPART * p, AVRMEM * m,
   return n_bytes;
 }
 
-static int usbasp_spi_paged_write(PROGRAMMER * pgm, AVRPART * p, AVRMEM * m,
-                                  unsigned int page_size,
-                                  unsigned int address, unsigned int n_bytes)
-{
+static int usbasp_spi_paged_write(const PROGRAMMER *pgm, const AVRPART *p, const AVRMEM *m,
+  unsigned int page_size, unsigned int address, unsigned int n_bytes) {
+
   int n;
   unsigned char cmd[4];
   int wbytes = n_bytes;
@@ -907,8 +939,7 @@ static struct sckoptions_t usbaspSCKoptions[] = {
  * Set sck period (in seconds)
  * Find next possible sck period and write it to the programmer.
  */
-static int usbasp_spi_set_sck_period(PROGRAMMER *pgm, double sckperiod)
-{
+static int usbasp_spi_set_sck_period(const PROGRAMMER *pgm, double sckperiod) {
   char clockoption = USBASP_ISP_SCK_AUTO;
   unsigned char res[4];
   unsigned char cmd[4];
@@ -980,8 +1011,7 @@ static int usbasp_spi_set_sck_period(PROGRAMMER *pgm, double sckperiod)
 }
 
 /* TPI specific functions */
-static void usbasp_tpi_send_byte(PROGRAMMER * pgm, uint8_t b)
-{
+static void usbasp_tpi_send_byte(const PROGRAMMER *pgm, uint8_t b) {
   unsigned char temp[4];
   memset(temp, 0, sizeof(temp));
 
@@ -991,8 +1021,7 @@ static void usbasp_tpi_send_byte(PROGRAMMER * pgm, uint8_t b)
 }
 
 
-static int usbasp_tpi_recv_byte(PROGRAMMER * pgm)
-{
+static int usbasp_tpi_recv_byte(const PROGRAMMER *pgm) {
   unsigned char temp[4];
   memset(temp, 0, sizeof(temp));
 
@@ -1006,8 +1035,7 @@ static int usbasp_tpi_recv_byte(PROGRAMMER * pgm)
 }
 
 
-static int usbasp_tpi_nvm_waitbusy(PROGRAMMER * pgm)
-{
+static int usbasp_tpi_nvm_waitbusy(const PROGRAMMER *pgm) {
   int retry;
 
   avrdude_message(MSG_DEBUG, "%s: usbasp_tpi_nvm_waitbusy() ...", progname);
@@ -1028,14 +1056,12 @@ static int usbasp_tpi_nvm_waitbusy(PROGRAMMER * pgm)
   return -1;
 }
 
-static int usbasp_tpi_cmd(PROGRAMMER * pgm, const unsigned char *cmd, unsigned char *res)
-{
+static int usbasp_tpi_cmd(const PROGRAMMER *pgm, const unsigned char *cmd, unsigned char *res) {
   avrdude_message(MSG_INFO, "%s: error: spi_cmd used in TPI mode: not allowed\n", progname);
   return -1;
 }
 
-static int usbasp_tpi_program_enable(PROGRAMMER * pgm, AVRPART * p)
-{
+static int usbasp_tpi_program_enable(const PROGRAMMER *pgm, const AVRPART *p) {
   int retry;
 
   avrdude_message(MSG_DEBUG, "%s: usbasp_tpi_program_enable()\n", progname);
@@ -1075,8 +1101,7 @@ static int usbasp_tpi_program_enable(PROGRAMMER * pgm, AVRPART * p)
   return 0;
 }
 
-static int usbasp_tpi_chip_erase(PROGRAMMER * pgm, AVRPART * p)
-{
+static int usbasp_tpi_chip_erase(const PROGRAMMER *pgm, const AVRPART *p) {
   int pr_0;
   int pr_1;
   int nvm_cmd;
@@ -1117,10 +1142,9 @@ static int usbasp_tpi_chip_erase(PROGRAMMER * pgm, AVRPART * p)
   return 0;
 }
 
-static int usbasp_tpi_paged_load(PROGRAMMER * pgm, AVRPART * p, AVRMEM * m,
-                                 unsigned int page_size,
-                                 unsigned int addr, unsigned int n_bytes)
-{
+static int usbasp_tpi_paged_load(const PROGRAMMER *pgm, const AVRPART *p, const AVRMEM *m,
+  unsigned int page_size, unsigned int addr, unsigned int n_bytes) {
+
   unsigned char cmd[4];
   unsigned char* dptr;
   int readed, clen, n;
@@ -1160,10 +1184,9 @@ static int usbasp_tpi_paged_load(PROGRAMMER * pgm, AVRPART * p, AVRMEM * m,
   return n_bytes;
 }
 
-static int usbasp_tpi_paged_write(PROGRAMMER * pgm, AVRPART * p, AVRMEM * m,
-                                  unsigned int page_size,
-                                  unsigned int addr, unsigned int n_bytes)
-{
+static int usbasp_tpi_paged_write(const PROGRAMMER *pgm, const AVRPART *p, const AVRMEM *m,
+  unsigned int page_size, unsigned int addr, unsigned int n_bytes) {
+
   unsigned char cmd[4];
   unsigned char* sptr;
   int writed, clen, n;
@@ -1227,12 +1250,11 @@ static int usbasp_tpi_paged_write(PROGRAMMER * pgm, AVRPART * p, AVRMEM * m,
   return n_bytes;
 }
 
-static int usbasp_tpi_set_sck_period(PROGRAMMER *pgm, double sckperiod)
-{
+static int usbasp_tpi_set_sck_period(const PROGRAMMER *pgm, double sckperiod) {
   return 0;
 }
-static int usbasp_tpi_read_byte(PROGRAMMER * pgm, AVRPART * p, AVRMEM * m, unsigned long addr, unsigned char * value)
-{
+
+static int usbasp_tpi_read_byte(const PROGRAMMER * pgm, const AVRPART *p, const AVRMEM *m, unsigned long addr, unsigned char *value) {
   unsigned char cmd[4];
   int n;
   uint16_t pr;
@@ -1257,15 +1279,15 @@ static int usbasp_tpi_read_byte(PROGRAMMER * pgm, AVRPART * p, AVRMEM * m, unsig
   return 0;
 }
 
-static int usbasp_tpi_write_byte(PROGRAMMER * pgm, AVRPART * p, AVRMEM * m, unsigned long addr, unsigned char data)
-{
+static int usbasp_tpi_write_byte(const PROGRAMMER *pgm, const AVRPART *p, const AVRMEM *m,
+  unsigned long addr, unsigned char data) { // FIXME: use avr_write_byte_cache() when implemented
+
   avrdude_message(MSG_INFO, "%s: error: usbasp_write_byte in TPI mode: all writes have to be done at page level\n", progname);
   return -1;
 }
 
 
-void usbasp_initpgm(PROGRAMMER * pgm)
-{
+void usbasp_initpgm(PROGRAMMER *pgm) {
   strcpy(pgm->type, "usbasp");
 
   /*
@@ -1276,23 +1298,23 @@ void usbasp_initpgm(PROGRAMMER * pgm)
   pgm->display        = usbasp_display;
   pgm->enable         = usbasp_enable;
   pgm->disable        = usbasp_disable;
-  pgm->program_enable = usbasp_spi_program_enable;
-  pgm->chip_erase     = usbasp_spi_chip_erase;
-  pgm->cmd            = usbasp_spi_cmd;
+  pgm->program_enable = usbasp_program_enable;
+  pgm->chip_erase     = usbasp_chip_erase;
+  pgm->cmd            = usbasp_cmd;
   pgm->open           = usbasp_open;
   pgm->close          = usbasp_close;
-  pgm->read_byte      = avr_read_byte_default;
-  pgm->write_byte     = avr_write_byte_default;
+  pgm->read_byte      = usbasp_read_byte;
+  pgm->write_byte     = usbasp_write_byte;
 
   /*
    * optional functions
    */
 
-  pgm->paged_write    = usbasp_spi_paged_write;
-  pgm->paged_load     = usbasp_spi_paged_load;
+  pgm->paged_write    = usbasp_paged_write;
+  pgm->paged_load     = usbasp_paged_load;
   pgm->setup          = usbasp_setup;
   pgm->teardown       = usbasp_teardown;
-  pgm->set_sck_period = usbasp_spi_set_sck_period;
+  pgm->set_sck_period = usbasp_set_sck_period;
   pgm->parseextparams = usbasp_parseextparms;
 
 }
@@ -1300,16 +1322,14 @@ void usbasp_initpgm(PROGRAMMER * pgm)
 
 #else /* HAVE_LIBUSB */
 
-static int usbasp_nousb_open (struct programmer_t *pgm, char * name)
-{
+static int usbasp_nousb_open(PROGRAMMER *pgm, const char *name) {
   avrdude_message(MSG_INFO, "%s: error: no usb support. please compile again with libusb installed.\n",
 	  progname);
 
   return -1;
 }
 
-void usbasp_initpgm(PROGRAMMER * pgm)
-{
+void usbasp_initpgm(PROGRAMMER *pgm) {
   strcpy(pgm->type, "usbasp");
 
   pgm->open           = usbasp_nousb_open;