From d0955aa6e07d4ece79012336552b886ff0b13bc9 Mon Sep 17 00:00:00 2001
From: Joerg Wunsch <j@uriah.heep.sax.de>
Date: Sun, 23 Nov 2014 21:49:56 +0000
Subject: [PATCH] Allow the -B option argument to be suffixed with Hz, kHz, or
 MHz, in order to specify a bitclock frequency rather than period.

git-svn-id: svn://svn.savannah.nongnu.org/avrdude/trunk/avrdude@1347 81a1dc3b-b13d-400b-aceb-764788c761c2
---
 ChangeLog        |  8 ++++++++
 NEWS             |  3 +++
 avrdude.1        |  4 +++-
 doc/avrdude.texi |  2 ++
 main.c           | 43 ++++++++++++++++++++++++++++++++++++++++++-
 5 files changed, 58 insertions(+), 2 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 10e5eebe..d9b1d828 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,11 @@
+2014-11-23  Joerg Wunsch <j.gnu@uriah.heep.sax.de>
+
+	* main.c: Allow the -B option argument to be suffixed with Hz,
+	kHz, or MHz, in order to specify a bitclock frequency rather than
+	period.
+	* avrdude.1: Document the -B option changes.
+	* doc/avrdude.texi: (Dito.)
+
 2014-11-23  Joerg Wunsch <j.gnu@uriah.heep.sax.de>
 
 	bug #40870: config nitpick: ATtiny25/45/85 have 1 calibration byte not 2
diff --git a/NEWS b/NEWS
index ecf411a1..5a80dc59 100644
--- a/NEWS
+++ b/NEWS
@@ -17,6 +17,9 @@ Current:
       used by all the more modern Atmel tools (AVRISPmkII, JTAGICEmkII
       in ISP mode, STK600 in ISP mode).
 
+    - The -B option can be suffixed with "Hz", "kHz", or "MHz", in
+      order to specify a bitclock frequency rather than period.
+
   * New programmers supported:
     - ...
 
diff --git a/avrdude.1 b/avrdude.1
index 5efa49d8..906f375f 100644
--- a/avrdude.1
+++ b/avrdude.1
@@ -18,7 +18,7 @@
 .\"
 .\" $Id$
 .\"
-.Dd DATE January 17, 2014
+.Dd DATE November 23, 2014
 .Os
 .Dt AVRDUDE 1
 .Sh NAME
@@ -257,6 +257,8 @@ programmer's entry of the configuration file.
 .It Fl B Ar bitclock
 Specify the bit clock period for the JTAG interface or the ISP clock (JTAG ICE only).
 The value is a floating-point number in microseconds.
+Alternatively, the value might be suffixed with "Hz", "kHz", or "MHz",
+in order to specify the bit clock frequency, rather than a period.
 The default value of the JTAG ICE results in about 1 microsecond bit
 clock period, suitable for target MCUs running at 4 MHz clock and
 above.
diff --git a/doc/avrdude.texi b/doc/avrdude.texi
index a3012050..240dd206 100644
--- a/doc/avrdude.texi
+++ b/doc/avrdude.texi
@@ -354,6 +354,8 @@ programmer's entry of the configuration file.
 @item -B @var{bitclock}
 Specify the bit clock period for the JTAG interface or the ISP clock (JTAG ICE only).
 The value is a floating-point number in microseconds.
+Alternatively, the value might be suffixed with "Hz", "kHz", or "MHz",
+in order to specify the bit clock frequency, rather than a period.
 The default value of the JTAG ICE results in about 1 microsecond bit
 clock period, suitable for target MCUs running at 4 MHz clock and
 above.
diff --git a/main.c b/main.c
index bfe2b596..7232e4f2 100644
--- a/main.c
+++ b/main.c
@@ -476,7 +476,48 @@ int main(int argc, char * argv [])
 
       case 'B':	/* specify JTAG ICE bit clock period */
 	bitclock = strtod(optarg, &e);
-	if ((e == optarg) || (*e != 0) || bitclock == 0.0) {
+	if (*e != 0) {
+	  /* trailing unit of measure present */
+	  int suffixlen = strlen(e);
+	  switch (suffixlen) {
+	  case 2:
+	    if ((e[0] != 'h' && e[0] != 'H') || e[1] != 'z')
+	      bitclock = 0.0;
+	    else
+	      /* convert from Hz to microseconds */
+	      bitclock = 1E6 / bitclock;
+	    break;
+
+	  case 3:
+	    if ((e[1] != 'h' && e[1] != 'H') || e[2] != 'z')
+	      bitclock = 0.0;
+	    else {
+	      switch (e[0]) {
+	      case 'M':
+	      case 'm':		/* no Millihertz here :) */
+		bitclock = 1.0 / bitclock;
+		break;
+
+	      case 'k':
+		bitclock = 1E3 / bitclock;
+		break;
+
+	      default:
+		bitclock = 0.0;
+		break;
+	      }
+	    }
+	    break;
+
+	  default:
+	    bitclock = 0.0;
+	    break;
+	  }
+	  if (bitclock == 0.0)
+	    avrdude_message(MSG_INFO, "%s: invalid bit clock unit of measure '%s'\n",
+			    progname, e);
+	}
+	if ((e == optarg) || bitclock == 0.0) {
 	  avrdude_message(MSG_INFO, "%s: invalid bit clock period specified '%s'\n",
                   progname, optarg);
           exit(1);