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Mon, 06 Jul 2026 01:01:04 -0700 (PDT) Received: from brighamcampbell.com ([2605:fb40:0:c09:9ca9:e0fd:b7cd:be76]) by smtp.gmail.com with ESMTPSA id a92af1059eb24-13b3c7ef5b3sm67268786c88.1.2026.07.06.01.01.03 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 06 Jul 2026 01:01:03 -0700 (PDT) From: Brigham Campbell Date: Mon, 06 Jul 2026 02:02:39 -0600 Subject: [PATCH] i2c-tools: Enable cross compilation Precedence: bulk X-Mailing-List: linux-i2c@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20260706-cross-compile-v1-1-e3ebdd485ce6@brighamcampbell.com> X-B4-Tracking: v=1; b=H4sIAAAAAAAC/6tWKk4tykwtVrJSqFYqSi3LLM7MzwNyDHUUlJIzE vPSU3UzU4B8JSMDIzMDcwMz3eSi/OJi3eT83ILMnFRdY7M0SwMTI1MzEwtDJaCegqLUtMwKsHn RsRB+cWlSVmpyCcgQpdpaAIeZ6z9xAAAA X-Change-ID: 20260706-cross-compile-36f904256481 To: linux-i2c@vger.kernel.org, Jean Delvare Cc: Wolfram Sang , Brigham Campbell X-Mailer: b4 0.15.2 X-Developer-Signature: v=1; a=openpgp-sha256; l=1827; i=me@brighamcampbell.com; h=from:subject:message-id; bh=xTnA/eD0J/2aSolda/yyqbIQlehiJ4TTbwgxfN63kR8=; b=owGbwMvMwCUWLsWS0KCyxZPxtFoSQ5Z3ooWFkkSoYqGspgSXEZepSUTTgvkMJ8SO9D7YfZ1lS ljRtTMdpSwMYlwMsmKKLCq3ZqlfnGz96GAE/wSYOaxMIEMYuDgFYCIM/xkZDoVJn9+0/n7xpF7u Opnbwt8eX22WL3ja2833vH2bp8qFLkaG6Q9Cpgju4+Fh2LNxn6Psyy8vc4RmhgS/NbjqqnRVwka FAQA= X-Developer-Key: i=me@brighamcampbell.com; a=openpgp; fpr=24DA9A27D1933BE2C1580F90571A04608024B449 Currently, the Makefile fails to change CC, AR, and STRIP variables from their default values[^1] because it uses the conditional variable assignment operator. The Makefile also doesn't allow for cross compilation without modification. Modify the Makefile to use unconditional assignment and allow the user to cross compile the software via the CROSS_COMPILE variable. [^1]: https://www.gnu.org/software/make/manual/html_node/Implicit-Variables.html Signed-off-by: Brigham Campbell --- Makefile | 9 ++++++--- README | 3 +++ 2 files changed, 9 insertions(+), 3 deletions(-) diff --git a/Makefile b/Makefile index a0d4269..2a51485 100644 --- a/Makefile +++ b/Makefile @@ -24,9 +24,12 @@ INSTALL_PROGRAM := $(INSTALL) -m 755 LN := ln -sf RM := rm -f -CC ?= gcc -AR ?= ar -STRIP ?= strip +# Use CROSS_COMPILE to specify the toolchain prefix. E.g. +# make CROSS_COMPILE=aarch64-linux-gnu- + +CC = $(CROSS_COMPILE)gcc +AR = $(CROSS_COMPILE)ar +STRIP = $(CROSS_COMPILE)strip CFLAGS ?= -O2 # When debugging, use the following instead diff --git a/README b/README index 502132f..1c83561 100644 --- a/README +++ b/README @@ -80,6 +80,9 @@ If you want to compile the tools against the static version of the library you can do: $ make USE_STATIC_LIB=1 +To compile for another platform, use the CROSS_COMPILE toolchain prefix option: + $ make CROSS_COMPILE=aarch64-linux-gnu- + Optionally, you can run "make strip" prior to "make install" if you want smaller binaries. However, be aware that this will prevent any further attempt to debug the library and tools. --- base-commit: 5852f5375eea6ca9dabf31f4772cb8b8ecc905d8 change-id: 20260706-cross-compile-36f904256481 Thanks! -- Brigham Campbell https://brighamcampbell.com