From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 20307C10F06 for ; Wed, 3 Apr 2019 12:40:59 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id E33662084C for ; Wed, 3 Apr 2019 12:40:58 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="Oso4gB2C" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E33662084C Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=sang-engineering.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org 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=K5P5UlPlqAl1T+i5wEbZ0BjBjVoBvE6aoftLeiP/Cvk=; b=Oso4gB2CsgEhY9TZK+GUlowyaM ok5iDZAhVuLhx/e0ENLgASWLg16euKja2cqXPU9EPug5ZBhn8O55rQntXawSuI21e5J/hmulB3hjz vERP6WHIScR6o4u97gSi+au0fznTHGXbBM1E2alkzSVVu2a52EZDkcINT+OoyjfOYRj0NsHJIKKge 110rYdhR+SJdOnDYobRKbFMY+SDEZGq+J58oYE496fHRyA+f0srFlYsujUUFANKLQVqSgWqVWrSmV YKu8/cP5LaLNtmNhk17Yo2yV82mMt+FMzNR3vv9b5WyrutngMn2TxHxu9ewVk1cW8G4EBxz4bgYiI NnEqwQCw==; 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 1hBfCG-0006n5-BM; Wed, 03 Apr 2019 12:40:52 +0000 Received: from sauhun.de ([88.99.104.3] helo=pokefinder.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1hBfC3-0006Uo-Ml for linux-arm-kernel@lists.infradead.org; Wed, 03 Apr 2019 12:40:42 +0000 Received: from localhost (p54B3311F.dip0.t-ipconnect.de [84.179.49.31]) by pokefinder.org (Postfix) with ESMTPSA id 1A1293E43CA; Wed, 3 Apr 2019 14:40:36 +0200 (CEST) From: Wolfram Sang To: linux-i2c@vger.kernel.org Subject: [PATCH 03/12] i2c: core: introduce callbacks for atomic transfers Date: Wed, 3 Apr 2019 14:40:10 +0200 Message-Id: <20190403124019.8947-4-wsa+renesas@sang-engineering.com> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20190403124019.8947-1-wsa+renesas@sang-engineering.com> References: <20190403124019.8947-1-wsa+renesas@sang-engineering.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190403_054040_039276_AD7FA6B6 X-CRM114-Status: GOOD ( 17.87 ) 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: Andy Shevchenko , Linus Walleij , linux-kernel@vger.kernel.org, linux-renesas-soc@vger.kernel.org, Wolfram Sang , linux-tegra@vger.kernel.org, Stefan Lengfeld , linux-omap@vger.kernel.org, Peter Rosin , linux-arm-kernel@lists.infradead.org MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org 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|smbus}_xfer callback if this new atomic 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 --- drivers/i2c/i2c-core-base.c | 6 +++++- drivers/i2c/i2c-core-smbus.c | 18 ++++++++++++++---- drivers/i2c/i2c-core.h | 7 +++++-- include/linux/i2c.h | 15 ++++++++++++--- 4 files changed, 36 insertions(+), 10 deletions(-) diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c index ad14f38a67e4..4e6300dc2c4e 100644 --- a/drivers/i2c/i2c-core-base.c +++ b/drivers/i2c/i2c-core-base.c @@ -1890,7 +1890,11 @@ 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 (i2c_in_atomic_xfer_mode() && adap->algo->master_xfer_atomic) + ret = adap->algo->master_xfer_atomic(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/drivers/i2c/i2c-core-smbus.c b/drivers/i2c/i2c-core-smbus.c index 357e083e8f45..fdb0fb9fb9aa 100644 --- a/drivers/i2c/i2c-core-smbus.c +++ b/drivers/i2c/i2c-core-smbus.c @@ -548,6 +548,9 @@ s32 __i2c_smbus_xfer(struct i2c_adapter *adapter, u16 addr, unsigned short flags, char read_write, u8 command, int protocol, union i2c_smbus_data *data) { + int (*xfer_func)(struct i2c_adapter *adap, u16 addr, + unsigned short flags, char read_write, + u8 command, int size, union i2c_smbus_data *data); unsigned long orig_jiffies; int try; s32 res; @@ -562,13 +565,20 @@ s32 __i2c_smbus_xfer(struct i2c_adapter *adapter, u16 addr, flags &= I2C_M_TEN | I2C_CLIENT_PEC | I2C_CLIENT_SCCB; - if (adapter->algo->smbus_xfer) { + xfer_func = adapter->algo->smbus_xfer; + if (i2c_in_atomic_xfer_mode()) { + if (adapter->algo->smbus_xfer_atomic) + xfer_func = adapter->algo->smbus_xfer_atomic; + else if (adapter->algo->master_xfer_atomic) + xfer_func = NULL; /* fallback to I2C emulation */ + } + + if (xfer_func) { /* Retry automatically on arbitration loss */ orig_jiffies = jiffies; for (res = 0, try = 0; try <= adapter->retries; try++) { - res = adapter->algo->smbus_xfer(adapter, addr, flags, - read_write, command, - protocol, data); + res = xfer_func(adapter, addr, flags, read_write, + command, protocol, data); if (res != -EAGAIN) break; if (time_after(jiffies, diff --git a/drivers/i2c/i2c-core.h b/drivers/i2c/i2c-core.h index deea47c576e5..f9d0c417b5a5 100644 --- a/drivers/i2c/i2c-core.h +++ b/drivers/i2c/i2c-core.h @@ -43,10 +43,13 @@ static inline int __i2c_lock_bus_helper(struct i2c_adapter *adap) { int ret = 0; - if (i2c_in_atomic_xfer_mode()) + if (i2c_in_atomic_xfer_mode()) { + WARN(!adap->algo->master_xfer_atomic && !adap->algo->smbus_xfer_atomic, + "No atomic I2C transfer handler for '%s'\n", dev_name(&adap->dev)); ret = i2c_trylock_bus(adap, I2C_LOCK_SEGMENT) ? 0 : -EAGAIN; - else + } else { i2c_lock_bus(adap, I2C_LOCK_SEGMENT); + } return ret; } diff --git a/include/linux/i2c.h b/include/linux/i2c.h index 758a6db864c9..03755d4c9229 100644 --- a/include/linux/i2c.h +++ b/include/linux/i2c.h @@ -499,9 +499,13 @@ 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_atomic: same as @master_xfer. Yet, only using atomic context + * so e.g. PMICs can be accessed very late before shutdown. Optional. * @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. + * @smbus_xfer_atomic: same as @smbus_xfer. Yet, only using atomic context + * so e.g. PMICs can be accessed very late before shutdown. Optional. * @functionality: Return the flags that this algorithm/adapter pair supports * from the I2C_FUNC_* flags. * @reg_slave: Register given client to I2C slave mode of this adapter @@ -512,9 +516,9 @@ 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{_atomic} fields 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 { /* @@ -528,9 +532,14 @@ struct i2c_algorithm { */ int (*master_xfer)(struct i2c_adapter *adap, struct i2c_msg *msgs, int num); + int (*master_xfer_atomic)(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); + int (*smbus_xfer_atomic)(struct i2c_adapter *adap, u16 addr, + unsigned short flags, char read_write, + u8 command, int size, union i2c_smbus_data *data); /* To determine what the adapter supports */ u32 (*functionality)(struct i2c_adapter *adap); -- 2.11.0 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel