makefile

I2C总线LINUX驱动程序

#  Makefile - Makefile for a Linux module for reading sensor data.
#  Copyright (c) 1998, 1999, 2000  Frodo Looijaard <[e-mail]>
#
#  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., 675 Mass Ave, Cambridge, MA 02139, USA.

# Everything you may want to change is in the top of this file. Usually, you
# can just use the defaults, fortunately.

# If your /bin/sh is not bash, change the below definition so that make can
# find bash. Or you can hope your sh-like shell understands all scripts.
# I think so, but I have not tested it.
#SHELL := /usr/bin/bash

# The currently running kernel version. This is used right below to
# determine where the kernel sources can be found.
KERNELVERSION := $(shell uname -r)

# The location of linux itself. This is used to find the kernel headers
# and other things.
#LINUX := /usr/src/linux
LINUX := $(shell if [ -L /lib/modules/$(KERNELVERSION)/build ] ; \
	then echo "/lib/modules/$(KERNELVERSION)/build" ; \
	else echo "/usr/src/linux" ; fi)
LINUX_HEADERS := $(LINUX)/include

# Determine whether we need to compile the kernel modules, or only the
# user-space utilities. By default, the kernel modules are compiled.
#COMPILE_KERNEL := 0
COMPILE_KERNEL := 1


# Uncomment the third line on SMP systems if the magic invocation fails. It
# is a bit complicated because SMP configuration changed around kernel 2.1.130
SMP := $(shell if grep -q '^SMP[[:space:]]*=' $(LINUX)/Makefile || \
                  grep -q '^[[:space:]]*\#define[[:space:]]*CONFIG_SMP[[:space:]]*1' $(LINUX_HEADERS)/linux/autoconf.h ; \
               then echo 1; else echo 0; fi)
#SMP := 0
#SMP := 1

# Uncomment the second or third line if the magic invocation fails.
# We need to know whether CONFIG_MODVERSIONS is defined.
MODVER := $(shell if cat $(LINUX_HEADERS)/linux/config.h $(LINUX_HEADERS)/linux/autoconf.h 2>/dev/null | grep -q '^[[:space:]]*\#define[[:space:]]*CONFIG_MODVERSIONS[[:space:]]*1'; then echo 1; else echo 0; fi)
#MODVER := 0
#MODVER := 1

# Your C compiler
CC := gcc

# This is the directory into which the modules will be installed.
# The magic invocation will return something like this:
#   /lib/modules/2.4.29
MODPREF := /lib/modules/$(shell $(CC) -I$(LINUX_HEADERS) -E etc/config.c | grep uts_release |cut -f 2 -d'"')

# Prevent 2.6+ users from using this package, as this won't work.
ifeq (,$(findstring /2.4., $(MODPREF)))
    ifeq (, $(MAKECMDGOALS))
        $(error For 2.6 kernels and later, you do not need this package)
    endif
    ifeq (install, $(MAKECMDGOALS))
        $(error For 2.6 kernels and later, you do not need this package)
    endif
endif

# This is the directory into which the header files will be installed.
# If you want to make sure your current kernel tree is not overwritten,
# the default should work. This is ignored for the i2c build system.
LINUX_INCLUDE_DIR := /usr/local/include/linux
#LINUX_INCLUDE_DIR := $(LINUX_HEADERS)/linux

# If you want to isntall everything at some other place then at which
# you will run it, DESTDIR defines a prefix used at installation-time.
DESTDIR :=

# Uncomment the second line if you are a developer. This will enable many
# additional warnings at compile-time
WARN := 0
#WARN := 1

MACHINE := $(shell uname -m)

##################################################
# Below this, nothing should need to be changed. #
##################################################

.PHONY: all clean install patch

# Note that this is a monolithic Makefile; it calls no sub-Makefiles,
# but instead, it compiles everything right from here. Yes, there are
# some distinct advantages to this; see the following paper for more info:
#   http://www.tip.net.au/~millerp/rmch/recu-make-cons-harm.html
# Note that is still uses Makefile fragments in sub-directories; these
# are called 'Module.mk'.

# Within each Module.mk, rules and dependencies can be added to targets
# all, install and clean. Use double colons instead of single ones
# to do this.

# The subdirectories we need to build things in
SRCDIRS := mkpatch
ifeq ($(COMPILE_KERNEL),1)
SRCDIRS += kernel
endif

# Some often-used commands with default options
MKDIR := mkdir -p
RMDIR := rmdir
RM := rm -f
BISON := bison
FLEX := flex
AR := ar
INSTALL := install
LN := ln -sfn
GREP := grep

# Determine the default compiler flags
# MODCFLAGS is to create in-kernel object files (modules)

CPPFLAGS := -I$(LINUX_HEADERS)
CFLAGS := -Wall -O2

ifeq ($(WARN),1)
CFLAGS += -W -Wstrict-prototypes -Wshadow -Wpointer-arith -Wcast-qual \
          -Wcast-align -Wwrite-strings -Wnested-externs -Winline
endif


# The -DEXPORT_SYMTAB is to keep the symbol export mechanism quiet.
MODCFLAGS := $(CFLAGS) -D__KERNEL__ -DMODULE -fomit-frame-pointer \
             -DEXPORT_SYMTAB -fno-strict-aliasing

ifeq ($(MACHINE),alpha)
MODCFLAGS += -ffixed-8 -mno-fp-regs -mcpu=ev56
endif

ifeq ($(MACHINE),x86_64)
MODCFLAGS += -fno-common -fomit-frame-pointer -mno-red-zone \
	     -mcmodel=kernel -fno-reorder-blocks -finline-limit=2000 -fno-strength-reduce
endif

ifeq ($(MACHINE),mips)
MODCFLAGS += -mabi=32 -mips3 -Wa,-32 -Wa,-mips3 -Wa,--trap
endif

ifeq ($(MACHINE),sparc32)
MODCFLAGS += -m32 -pipe -mno-fpu -fcall-used-g5 -fcall-used-g7
endif

ifeq ($(MACHINE),sparc64)
MODCFLAGS += -m64 -pipe -mno-fpu -mcpu=ultrasparc -mcmodel=medlow \
	     -ffixed-g4 -fcall-used-g5 -fcall-used-g7 -Wno-sign-compare \
	     -Wa,--undeclared-regs
endif

ifeq ($(SMP),1)
MODCPPFLAGS += -D__SMP__
endif

ifeq ($(MODVER),1)
MODCPPFLAGS += -DMODVERSIONS -include $(LINUX_HEADERS)/linux/modversions.h
endif

# This magic is from the kernel Makefile.
# Extra cflags for kbuild 2.4.  The default is to forbid includes by kernel code
# from user space headers.
kbuild_2_4_nostdinc := -nostdinc $(shell LC_ALL=C $(CC) -print-search-dirs | sed -ne 's/install: \(.*\)/-I \1include/gp')
MODCPPFLAGS += $(CPPFLAGS) $(kbuild_2_4_nostdinc)

.PHONY: dep
# Make all the default rule
all::

# Include all makefiles for sub-modules
INCLUDEFILES :=
ifneq ($(SRCDIRS),)
include $(patsubst %,%/Module.mk,$(SRCDIRS))
endif
ifneq ($(MAKECMDGOALS),clean)
ifneq ($(INCLUDEFILES),)
include $(INCLUDEFILES)
endif
endif

# Making the dependency files - done automatically!
dep :

all ::
ifeq ($(shell if grep -q '^CONFIG_I2C=y' $(LINUX)/.config; then echo 1; fi),1)
	@echo "*************** WARNING *************************** WARNING ***************"
	@echo "***                                                                     ***"
	@echo "*** You have I2C support built into your kernel (CONFIG_I2C=y). Unless  ***"
	@echo "*** you know what you are doing, installing our version of i2c will not ***"
	@echo "*** work. Newly built i2c modules probably won't load. Other modules    ***"
	@echo "*** that rely on the i2c layer, such as lm_sensors, will fail to        ***"
	@echo "*** compile. Please consider compiling your kernel again with I2C       ***"
	@echo "*** support enabled as modules or disabled.                             ***"
	@echo "***                                                                     ***"
	@echo "*************** WARNING *************************** WARNING ***************"
endif

install :: all
ifeq ($(DESTDIR),)
	-/sbin/depmod -a
else
	@echo "*** This is a \`staged' install using \"$(DESTDIR)\" as prefix."
	@echo "***"
	@echo "*** Once the modules have been moved to their final destination"
	@echo "*** you must run the command \"/sbin/depmod -a\"."
	@echo "***"
	@echo "*** Alternatively, if you build a package (e.g. rpm), include the"
	@echo "*** command \"/sbin/depmod -a\" in the post-(un)install procedure."
	@echo "***"
	@echo "*** If the depmod command mentioned above generates errors, you should"
	@echo "*** pay particular attention to the note #1 below."
endif
	@echo "*** Installation successful!"
	@echo "*** Important notes:"
	@echo "*** 1* Compatibility with the Linux 2.4 kernel has been restored."
	@echo "*** 2* The i2c-elektor and i2c-pcf-epp modules were not built. If you"
	@echo "***    need them, you have to use compilation option 3 as described in"
	@echo "***    the INSTALL file."

clean::

$(LINUX)/.config:
	@echo
	@echo "Error - missing file $(LINUX)/.config !! "
	@echo "  Verify kernel source is in $(LINUX) and then"
	@echo "  cd to $(LINUX) and run 'make config' !!"
	@echo
	@echo "Exception: if you're using a stock RedHat/Fedora kernel..."
	@echo "  (1) Install the appropriate kernel-source RPM."
	@echo "  (2) Copy the appropriate config..."
	@echo "      from $(LINUX)/configs/<...>"
	@echo "      to $(LINUX)/.config"
	@echo "  (3) Do *NOT* 'make dep' or 'make config'."
	@echo
	@exit 1

# Here, we define all implicit rules we want to use.

.SUFFIXES:

# We need to create dependency files. Tricky. We sed rule puts dir/file.d and
# dir/file.c in front of the dependency file rule.

# .o files are used for modules
# depend on the kernel config file!
%.o: %.c $(LINUX)/.config
	$(CC) $(MODCPPFLAGS) $(MODCFLAGS) -c $< -o $@

%.d: %.c $(LINUX)/.config
	$(CC) -M -MG $(MODCPPFLAGS) $(MODCFLAGS) $< | \
	sed -e 's@^\(.*\)\.o:@$*.d $*.o: Makefile '`dirname $*.d`/Module.mk' @' > $@