From patchwork Thu Sep 20 16:14:23 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Wolfram Sang X-Patchwork-Id: 10608029 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id E19B76CB for ; Thu, 20 Sep 2018 16:15:35 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 92CE72B6ED for ; Thu, 20 Sep 2018 16:15:23 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 83E0E2DBC5; Thu, 20 Sep 2018 16:15:23 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.9 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,MAILING_LIST_MULTI,RCVD_IN_DNSWL_NONE autolearn=unavailable version=3.3.1 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 083C02B6ED for ; Thu, 20 Sep 2018 16:15:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:MIME-Version:Cc:List-Subscribe: List-Help:List-Post:List-Archive:List-Unsubscribe:List-Id:References: In-Reply-To:Message-Id:Date:Subject:To:From:Reply-To:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Owner; bh=XSi+8frQEidK5KhY6EvigsaY6XcNu1J4a6bOeRtHMxY=; b=nUUMKF+OL0JD8gKtW05t8577VT 7tVDfZT/fmaGqWFKIHuPJlb9YWlPZkn6yJzn9DW1L0So9k7dOCZsB8ROYNXPn3BMBGfNaIGpkzpbn aK97B2BRHo+t9KGI63l+vjOe/Xy+QZcohAzaVm3CZu8sZ193ZULc/u5jWQA18SxVLZNaKA9Jydu+V agc5OaxldQC5XVREDiATY+5vlIwkB88gOTdzfTSFyvxcMBdPsK4WOysq+fy/3kVncinqUvm6aTMu9 I9NuVsLWCGZ564D8GuvJRz5SvO/Z8GvPnBjU9ocjMubUo7kTE8zpVvaSKHHN9WGgDEC+OXEge4pJt DnVKkVIg==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1g31bg-0003kx-Tp; Thu, 20 Sep 2018 16:15:09 +0000 Received: from merlin.infradead.org ([2001:8b0:10b:1231::1]) by bombadil.infradead.org with esmtps (Exim 4.90_1 #2 (Red Hat Linux)) id 1g31bQ-0003cZ-Vv for linux-arm-kernel@bombadil.infradead.org; Thu, 20 Sep 2018 16:14:52 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=merlin.20170209; h=References:In-Reply-To:Message-Id:Date: Subject:Cc:To:From:Sender:Reply-To:MIME-Version:Content-Type: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=sw7aD1Vz8Q9rSR/28NjgrlKQ0oO9uq1ft+yiGk1zwjE=; b=HVhVSO4oYd6tMF2IRN2cu86Oy JkPqv9BY51BCRBbndvW5dRWxIjd9vkpGgNhJt6vA4OInnZQQbIRY4RKf/qn+N6vhTGZ1Wmg3v1iAX Hb4DlIZY5xaYEoRU75VTjoNsk1aA9ekV+BxS27bH2T+r7BVz46hDUNaeshV/9bhb4LfyoyX6nui2C sZTwvSfXwq1yDOJimFTlD5vvJ0FPvdysvTZXCMCPjHAeAO3/SyPg92ocy2rrUJn/7TktRkT9+HU4c egG7ntoAQbhsheFPtSIhZxaw0082j9s1Pzw6WAkcQoaFSqbqHxYcXJnHWsiAmKs7866vp8EJc29hb KgzbQI1iQ==; Received: from sauhun.de ([88.99.104.3] helo=pokefinder.org) by merlin.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1g31bM-0003jy-H1 for linux-arm-kernel@lists.infradead.org; Thu, 20 Sep 2018 16:14:50 +0000 Received: from localhost (i577B999D.versanet.de [87.123.153.157]) by pokefinder.org (Postfix) with ESMTPSA id 76A4C2E35A8; Thu, 20 Sep 2018 18:14:34 +0200 (CEST) From: Wolfram Sang To: linux-i2c@vger.kernel.org Subject: [RFC PATCH 4/4] i2c: core: introduce master_xfer_irqless callback Date: Thu, 20 Sep 2018 18:14:23 +0200 Message-Id: <20180920161423.13990-5-wsa+renesas@sang-engineering.com> X-Mailer: git-send-email 2.18.0 In-Reply-To: <20180920161423.13990-1-wsa+renesas@sang-engineering.com> References: <20180920161423.13990-1-wsa+renesas@sang-engineering.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20180920_121448_825239_C5B8C013 X-CRM114-Status: GOOD ( 17.03 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Tero Kristo , preid@electromag.com.au, Keerthy , Andy Shevchenko , linux-renesas-soc@vger.kernel.org, Wolfram Sang , Grygorii Strashko , Stefan Lengfeld , linux-omap@vger.kernel.org, linux-arm-kernel@lists.infradead.org MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Virus-Scanned: ClamAV using ClamSMTP We had the request to access devices very late when interrupts are not available anymore multiple times now. Mostly to prepare shutdown or reboot. Allow adapters to specify a specific callback for this case. Note that we fall back to the generic master_xfer callback if this new irqless one is not present. This is intentional to preserve the previous behaviour and avoid regressions. Because there are drivers not using interrupts or because it might have worked "accidently" before. Signed-off-by: Wolfram Sang Acked-by: Peter Rosin --- drivers/i2c/i2c-core-base.c | 6 +++++- include/linux/i2c.h | 10 +++++++--- 2 files changed, 12 insertions(+), 4 deletions(-) diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c index 904b4d2ebefa..f827446c3089 100644 --- a/drivers/i2c/i2c-core-base.c +++ b/drivers/i2c/i2c-core-base.c @@ -1887,7 +1887,11 @@ int __i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num) /* Retry automatically on arbitration loss */ orig_jiffies = jiffies; for (ret = 0, try = 0; try <= adap->retries; try++) { - ret = adap->algo->master_xfer(adap, msgs, num); + if ((in_atomic() || irqs_disabled()) && adap->algo->master_xfer_irqless) + ret = adap->algo->master_xfer_irqless(adap, msgs, num); + else + ret = adap->algo->master_xfer(adap, msgs, num); + if (ret != -EAGAIN) break; if (time_after(jiffies, orig_jiffies + adap->timeout)) diff --git a/include/linux/i2c.h b/include/linux/i2c.h index 65b4eaed1d96..11e615123bd0 100644 --- a/include/linux/i2c.h +++ b/include/linux/i2c.h @@ -498,6 +498,8 @@ i2c_register_board_info(int busnum, struct i2c_board_info const *info, * @master_xfer: Issue a set of i2c transactions to the given I2C adapter * defined by the msgs array, with num messages available to transfer via * the adapter specified by adap. + * @master_xfer_irqless: same as master_xfer. Yet, not using any interrupts + * so e.g. PMICs can be accessed very late before shutdown * @smbus_xfer: Issue smbus transactions to the given I2C adapter. If this * is not present, then the bus layer will try and convert the SMBus calls * into I2C transfers instead. @@ -511,9 +513,9 @@ i2c_register_board_info(int busnum, struct i2c_board_info const *info, * be addressed using the same bus algorithms - i.e. bit-banging or the PCF8584 * to name two of the most common. * - * The return codes from the @master_xfer field should indicate the type of - * error code that occurred during the transfer, as documented in the kernel - * Documentation file Documentation/i2c/fault-codes. + * The return codes from the @master_xfer{_irqless} field should indicate the + * type of error code that occurred during the transfer, as documented in the + * Kernel Documentation file Documentation/i2c/fault-codes. */ struct i2c_algorithm { /* If an adapter algorithm can't do I2C-level access, set master_xfer @@ -524,6 +526,8 @@ struct i2c_algorithm { processed, or a negative value on error */ int (*master_xfer)(struct i2c_adapter *adap, struct i2c_msg *msgs, int num); + int (*master_xfer_irqless)(struct i2c_adapter *adap, + struct i2c_msg *msgs, int num); int (*smbus_xfer) (struct i2c_adapter *adap, u16 addr, unsigned short flags, char read_write, u8 command, int size, union i2c_smbus_data *data);