From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtpout-02.galae.net (smtpout-02.galae.net [185.246.84.56]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 1C2FE334C20 for ; Tue, 23 Dec 2025 13:22:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=185.246.84.56 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1766496178; cv=none; b=V0CnDOoKb9jSe4ZCjb9P15k263QPI7ORnnnR+gbQWB2x4I4f5SfIVe16Ci7t+c9xRElUrZGy/v7eyZo8seYqr5w+kCZfsxY8vxCnqmdC/6WL2v5szNoMiETNVTszdKFOKL3m1XoxkQAWDs7EuO4aOHdxwqnVE2ayLPKyiQcHukY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1766496178; c=relaxed/simple; bh=kuY4fCQ5H1fzznT7laMzOen2TAmIsB4nh4zgpnY49NA=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=rqtCCK61ICyxA8KGAt7YuPz95Xt6oLk+DycaFfEKmBKkT2D/kloWJkNkz78jaFFcwY67ceiSB2aFA0noYnZyVFbwypZPJgdDa4du6IDFMfWzWIzG6prLaRweb8mbwlVa0zw23QjBKKPVDP4oMc69mfYHBBEh/Kw2r89svnOnPcQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=bootlin.com; spf=pass smtp.mailfrom=bootlin.com; dkim=pass (2048-bit key) header.d=bootlin.com header.i=@bootlin.com header.b=rptBqTIm; arc=none smtp.client-ip=185.246.84.56 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=bootlin.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=bootlin.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=bootlin.com header.i=@bootlin.com header.b="rptBqTIm" Received: from smtpout-01.galae.net (smtpout-01.galae.net [212.83.139.233]) by smtpout-02.galae.net (Postfix) with ESMTPS id 599761A23A7 for ; Tue, 23 Dec 2025 13:22:54 +0000 (UTC) Received: from mail.galae.net (mail.galae.net [212.83.136.155]) by smtpout-01.galae.net (Postfix) with ESMTPS id 2A24860716; Tue, 23 Dec 2025 13:22:54 +0000 (UTC) Received: from [127.0.0.1] (localhost [127.0.0.1]) by localhost (Mailerdaemon) with ESMTPSA id 3EFD610AB0AA5; Tue, 23 Dec 2025 14:22:53 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bootlin.com; s=dkim; t=1766496173; h=from:subject:date:message-id:to:cc:mime-version:content-type: content-transfer-encoding:in-reply-to:references; bh=w3XeT/PkJBG/FENqfsCItJm1/AdbkiY+2zNAbxPoxSs=; b=rptBqTImm+m7orLF54+k9tH1813r98S/MZ5jhVDIvdV2pB6KG39neOQa1ES2YbiOUP068I mYIibOqUzIVhS8xKr92zcnBTQT5hdQcUU4Y9P4hawvsL3p1idGhkFfyE3tQDdY3+rVyHqu pSNRmrUyNNvlXIF65DGBkKL2ioYyjB68XWq2iQZXcc6Khwz+lysxAbzlQvYqFSBN3wcpWd T5PMGCqohsBNCt/8yKScaUZhCpG7NbNMwntLEQYus/XWZ1bhZIuSnbxmUyGIvDOz1IVH7x rePsw1D6VqrSIU02Wc2CkFn7/oC3C3UK/tmEzzIHCmkgA1v/GMJjDEkZSdlKoQ== From: =?utf-8?q?Beno=C3=AEt_Monin?= Date: Tue, 23 Dec 2025 14:22:43 +0100 Subject: [PATCH i2c-tools v2 2/2] i2ctransfer: Add optional message modifier flags 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: 8bit Message-Id: <20251223-msg-flags-v2-2-8d934a4366e2@bootlin.com> References: <20251223-msg-flags-v2-0-8d934a4366e2@bootlin.com> In-Reply-To: <20251223-msg-flags-v2-0-8d934a4366e2@bootlin.com> To: linux-i2c@vger.kernel.org Cc: Jean Delvare , Thomas Petazzoni , =?utf-8?q?Beno=C3=AEt_Monin?= X-Mailer: b4 0.14.3 X-Last-TLS-Session-Version: TLSv1.3 Allow setting protocol mangling and repeated start elision flags of an i2c message with a set of optional command-line flags. These optional flags are parsed at the beginning of the DESC field up to a read or write flag. For example, to read one byte from address 0x50 followed by a stop, then write two bytes at 0x54 on bus 0, one would call i2ctransfer as follow: i2ctransfer 0 pr1@0x50 w2@0x54 0x10 0x20 Since the new flags are optional, this patch preserves the compatibility of the i2ctransfer syntax. Signed-off-by: Benoît Monin --- tools/i2ctransfer.8 | 26 +++++++++++++++++++++++++- tools/i2ctransfer.c | 34 +++++++++++++++++++++++++--------- 2 files changed, 50 insertions(+), 10 deletions(-) diff --git a/tools/i2ctransfer.8 b/tools/i2ctransfer.8 index 4bdf436..45c744d 100644 --- a/tools/i2ctransfer.8 +++ b/tools/i2ctransfer.8 @@ -96,8 +96,11 @@ The number of blocks is limited by the Linux Kernel and defined by I2C_RDWR_IOCT .I desc blocks are composed like this: -.I {r|w}[@address] +.I [inpst]{r|w}[@address] +.TP +.B [inpst] +specifies optional MESSAGE MODIFIER FLAGS. See the section below for details. .TP .B {r|w} specifies if the message is read or write @@ -141,6 +144,27 @@ decrease value by 1 until end of message (i.e. 0xff- means 0xff, 0xfe, 0xfd, ... p use value as seed for an 8 bit pseudo random sequence (i.e. 0p means 0x00, 0x50, 0xb0, ...) +.SH "MESSAGE MODIFIER FLAGS" +.PP +These optional flags can be used to change the handling of a message when it is sent on the bus. +Note that not all flags (or any) may be supported by your particular hardware. + +.TP +.B i +ignore NACK from client, treat them as ACK. +.TP +.B n +in a read message, master ACK/NACK bit is skipped. +.TP +.B p +emit a STOP after the message. +.TP +.B s +skip repeated start. +.TP +.B t +toggle read/write bit. + .SH EXAMPLES .PP On bus 0, from an EEPROM at address 0x50, read 8 byte from offset 0x64 diff --git a/tools/i2ctransfer.c b/tools/i2ctransfer.c index 4db98e3..921ffaa 100644 --- a/tools/i2ctransfer.c +++ b/tools/i2ctransfer.c @@ -52,9 +52,16 @@ static void help(void) " -V version info\n" " -y yes to all confirmations\n" " I2CBUS is an integer or an I2C bus name\n" - " DESC describes the transfer in the form: {r|w}LENGTH[@address]\n" - " 1) read/write-flag 2) LENGTH (range 0-65535, or '?')\n" - " 3) I2C address (use last one if omitted)\n" + " DESC describes the transfer in the form: [inpst]{r|w}LENGTH[@address]\n" + " 1) optional message modifier flags\n" + " i: ignore NACK from client\n" + " n: no master ACK/NACK bit in a read message\n" + " p: emit a STOP after the message\n" + " s: skip repeated start\n" + " t: toggle read/write bit\n" + " 2) mandatory read/write flag\n" + " 3) LENGTH (range 0-65535, or '?')\n" + " 4) I2C address (use last one if omitted)\n" " DATA are LENGTH bytes for a write message. They can be shortened by a suffix:\n" " = (keep value constant until LENGTH)\n" " + (increase value by 1 until LENGTH)\n" @@ -202,12 +209,21 @@ int main(int argc, char *argv[]) case PARSE_GET_DESC: flags = 0; - switch (*arg_ptr++) { - case 'r': flags |= I2C_M_RD; break; - case 'w': break; - default: - fprintf(stderr, "Error: Invalid direction\n"); - goto err_out_with_arg; + for (int done = 0; !done; ) { + switch (*arg_ptr++) { + /* optional flags */ + case 'i': flags |= I2C_M_IGNORE_NAK; break; + case 'n': flags |= I2C_M_NO_RD_ACK; break; + case 'p': flags |= I2C_M_STOP; break; + case 's': flags |= I2C_M_NOSTART; break; + case 't': flags |= I2C_M_REV_DIR_ADDR; break; + /* mandatory flags */ + case 'r': flags |= I2C_M_RD; done = 1; break; + case 'w': done = 1; break; + default: + fprintf(stderr, "Error: Invalid flag\n"); + goto err_out_with_arg; + } } if (*arg_ptr == '?') { -- 2.52.0