Add code to open and close PHC devices.

Signed-off-by: Richard Cochran <richardcochran@gmail.com>

makefile

@@ -0,0 +1,53 @@
+#
+# Copyright (C) 2011 Richard Cochran <richardcochran@gmail.com>
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License along
+# with this program; if not, write to the Free Software Foundation, Inc.,
+# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+
+KBUILD_OUTPUT ?= /lib/modules/$(shell uname -r)/build
+
+DEBUG	=
+CC	= gcc
+INC	= -I$(KBUILD_OUTPUT)/usr/include
+CFLAGS	= -Wall $(INC) $(DEBUG)
+LDFLAGS	=
+LDLIBS	= -lm -lrt
+PRG	= linuxptp
+OBJ	= phc.o
+
+SRC	= $(OBJ:.o=.c)
+DEPEND	= $(OBJ:.o=.d)
+srcdir	:= $(dir $(lastword $(MAKEFILE_LIST)))
+VPATH	= $(srcdir)
+
+all: $(OBJ)
+
+linuxptp: $(OBJ)
+
+clean:
+	rm -f $(OBJ) $(DEPEND)
+
+distclean: clean
+	rm -f $(PRG)
+
+# Implicit rule to generate a C source file's dependencies.
+%.d: %.c
+	@echo DEPEND $<; \
+	rm -f $@; \
+	$(CC) -MM $(CPPFLAGS) $(CFLAGS) $< > $@.$$$$; \
+	sed 's,\($*\)\.o[ :]*,\1.o $@ : ,g' < $@.$$$$ > $@; \
+	rm -f $@.$$$$
+
+-include $(DEPEND)
+

phc.c

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+/**
+ * @file phc.c
+ * @note Copyright (C) 2011 Richard Cochran <richardcochran@gmail.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <unistd.h>
+
+#include "phc.h"
+
+clockid_t phc_open(char *phc)
+{
+	int fd = open(phc, O_RDWR);
+
+	return fd < 0 ? CLOCK_INVALID : FD_TO_CLOCKID(fd);
+}
+
+void phc_close(clockid_t clkid)
+{
+	if (clkid == CLOCK_INVALID)
+		return;
+
+	close(CLOCKID_TO_FD(clkid));
+}

phc.h

@@ -0,0 +1,40 @@
+/**
+ * @file phc.h
+ * @note Copyright (C) 2011 Richard Cochran <richardcochran@gmail.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+#ifndef HAVE_PHC_H
+#define HAVE_PHC_H
+
+#include "missing.h"
+
+/**
+ * Opens a PTP hardware clock device.
+ *
+ * @param phc The device to open.
+ *
+ * @return A valid clock ID on success, CLOCK_INVALID otherwise.
+ */
+clockid_t phc_open(char *phc);
+
+/**
+ * Closes a PTP hardware clock device.
+ *
+ * @param clkid A clock ID obtained using phc_open().
+ */
+void phc_close(clockid_t clkid);
+
+#endif