From patchwork Mon Jan 14 18:53:21 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Doug Anderson X-Patchwork-Id: 1973331 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-process-083081@patchwork2.kernel.org Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) by patchwork2.kernel.org (Postfix) with ESMTP id 5A23DDF2E1 for ; Mon, 14 Jan 2013 18:58:18 +0000 (UTC) Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.76 #1 (Red Hat Linux)) id 1TupB2-0006gP-Eu; Mon, 14 Jan 2013 18:54:35 +0000 Received: from mail-bk0-f73.google.com ([209.85.214.73]) by merlin.infradead.org with esmtps (Exim 4.76 #1 (Red Hat Linux)) id 1TupA6-0006MO-4r for linux-arm-kernel@lists.infradead.org; Mon, 14 Jan 2013 18:53:36 +0000 Received: by mail-bk0-f73.google.com with SMTP id jf3so284938bkc.0 for ; Mon, 14 Jan 2013 10:53:32 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20120113; h=x-received:from:to:cc:subject:date:message-id:x-mailer:in-reply-to :references:x-gm-message-state; bh=pn1DXjpxCTbvnM7Zp74tm21jxCjat+uQPbmRBzjf5Kc=; b=RsUK8G1NOSMredWb9c+LFNOP63bsSfk1ibNnfxyu2hk3gAXobacmlxBG0uWhUwXj5I 46u0H/WH42VlX231vDIa27TTCqtavO7zUcNnrouozYJRMiutyT9kjI+mWB2rwx6lltJv LRwWiZU5/whEU0IKq054fgdWuiDB9O/0kx1OT72Ay1RYaU7QzkPOGWz4eQ/RBqQ2Vf2Z vMbdrElduWQEOFUZRkiUGcqzAMjEtlF7qDTD97q/q4MBOxxBwXSEJXrUBO30vrkvFbcU bKnrRQok1ZiXM/kkCk26uux+vNMeQdCBSUXufsflia/Dnqph8H55rDKv5hSn93CVcyiO CjNg== X-Received: by 10.14.201.1 with SMTP id a1mr108025890eeo.3.1358189612055; Mon, 14 Jan 2013 10:53:32 -0800 (PST) Received: from hpza10.eem.corp.google.com ([74.125.121.33]) by gmr-mx.google.com with ESMTPS id z44si5240142een.0.2013.01.14.10.53.31 (version=TLSv1 cipher=AES128-SHA bits=128/128); Mon, 14 Jan 2013 10:53:32 -0800 (PST) Received: from tictac.mtv.corp.google.com (tictac.mtv.corp.google.com [172.22.73.80]) by hpza10.eem.corp.google.com (Postfix) with ESMTP id 2CBF3200057; Mon, 14 Jan 2013 10:53:31 -0800 (PST) Received: by tictac.mtv.corp.google.com (Postfix, from userid 121310) id 6F75380731; Mon, 14 Jan 2013 10:53:30 -0800 (PST) From: Doug Anderson To: linux-i2c@vger.kernel.org, Mark Brown Subject: [PATCH v2 1/2] i2c-core: dt: Pick i2c bus number from i2c alias if present Date: Mon, 14 Jan 2013 10:53:21 -0800 Message-Id: <1358189602-24180-2-git-send-email-dianders@chromium.org> X-Mailer: git-send-email 1.7.7.3 In-Reply-To: <1358189602-24180-1-git-send-email-dianders@chromium.org> References: <1357927027-4857-2-git-send-email-dianders@chromium.org> <1358189602-24180-1-git-send-email-dianders@chromium.org> X-Gm-Message-State: ALoCoQmexGbJcxexh4leezEtpnVEsbC2b5S0VcB8qeHijxdK9j5tuF0sGuAjuixY1V43L5YEzfv4QKas8giRzGtJlKJ+kK6/a2lvNf1aUKfHGdkaDK84PVRuZ/fG9Q4T46udhe/4hfd4baoDzs8Kqy+wAkb8rwDo4GN1Tva/Ish1zQw2kTDqshN/bO7Hsa+UGKUOB/gEtLYyJKb9kzalN3OpvC5WXFHQQg== X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20130114_135335_278134_72A97B7B X-CRM114-Status: GOOD ( 19.42 ) X-Spam-Score: -0.3 (/) X-Spam-Report: SpamAssassin version 3.3.2 on merlin.infradead.org summary: Content analysis details: (-0.3 points) pts rule name description ---- ---------------------- -------------------------------------------------- 3.0 KHOP_BIG_TO_CC Sent to 10+ recipients instaed of Bcc or a list -0.7 RCVD_IN_DNSWL_LOW RBL: Sender listed at http://www.dnswl.org/, low trust [209.85.214.73 listed in list.dnswl.org] -0.0 SPF_PASS SPF: sender matches SPF record -0.7 RP_MATCHES_RCVD Envelope sender domain matches handover relay domain -1.9 BAYES_00 BODY: Bayes spam probability is 0 to 1% [score: 0.0000] Cc: Kukjin Kim , Arnd Bergmann , Padmavathi Venna , linux-kernel@vger.kernel.org, Wolfram Sang , Haojian Zhuang , Doug Anderson , linux-samsung-soc@vger.kernel.org, Thomas Abraham , Ben Dooks , Olof Johansson , Sylwester Nawrocki , linux-arm-kernel@lists.infradead.org X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: linux-arm-kernel-bounces@lists.infradead.org Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org This allows you to get the equivalent functionality of i2c_add_numbered_adapter() with all data in the device tree and no special case code in your driver. This is a common device tree technique. For quick reference, the FDT syntax for using an alias to provide an ID looks like: aliases { i2c0 = &i2c_0; i2c1 = &i2c_1; }; Signed-off-by: Doug Anderson Acked-by: Haojian Zhuang Acked-by: Olof Johansson --- Changes in v2: None drivers/i2c/i2c-core.c | 105 +++++++++++++++++++++++++++++++++++------------- 1 files changed, 77 insertions(+), 28 deletions(-) diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c index e388590..a60ed6d 100644 --- a/drivers/i2c/i2c-core.c +++ b/drivers/i2c/i2c-core.c @@ -921,13 +921,81 @@ out_list: } /** + * i2c_get_number_from_dt - get the adapter number based on dt alias + * @adap: the adapter to look at + * + * Check whether there's an alias in the FDT that gives an ID for this i2c + * device. Use an alias like "i2c", like: + * aliases { + * i2c0 = &i2c_0; + * i2c1 = &i2c_1; + * }; + * + * Returns the ID if found. If no alias is found returns -1. + */ +static int i2c_get_number_from_dt(struct i2c_adapter *adap) +{ + struct device *dev = &adap->dev; + int id; + + if (!dev->of_node) + return -1; + + id = of_alias_get_id(dev->of_node, "i2c"); + if (id < 0) + return -1; + return id; +} + +/** + * _i2c_add_numbered_adapter - i2c_add_numbered_adapter where nr is never -1 + * @adap: the adapter to register (with adap->nr initialized) + * Context: can sleep + * + * See i2c_add_numbered_adapter() for details. + */ +static int _i2c_add_numbered_adapter(struct i2c_adapter *adap) +{ + int id; + int status; + + /* Handled by wrappers */ + BUG_ON(adap->nr == -1); + + if (adap->nr & ~MAX_IDR_MASK) + return -EINVAL; + +retry: + if (idr_pre_get(&i2c_adapter_idr, GFP_KERNEL) == 0) + return -ENOMEM; + + mutex_lock(&core_lock); + /* "above" here means "above or equal to", sigh; + * we need the "equal to" result to force the result + */ + status = idr_get_new_above(&i2c_adapter_idr, adap, adap->nr, &id); + if (status == 0 && id != adap->nr) { + status = -EBUSY; + idr_remove(&i2c_adapter_idr, id); + } + mutex_unlock(&core_lock); + if (status == -EAGAIN) + goto retry; + + if (status == 0) + status = i2c_register_adapter(adap); + return status; +} + +/** * i2c_add_adapter - declare i2c adapter, use dynamic bus number * @adapter: the adapter to add * Context: can sleep * * This routine is used to declare an I2C adapter when its bus number - * doesn't matter. Examples: for I2C adapters dynamically added by - * USB links or PCI plugin cards. + * doesn't matter or when its bus number is specified by an dt alias. + * Examples of bases when the bus number doesn't matter: I2C adapters + * dynamically added by USB links or PCI plugin cards. * * When this returns zero, a new bus number was allocated and stored * in adap->nr, and the specified adapter became available for clients. @@ -937,6 +1005,12 @@ int i2c_add_adapter(struct i2c_adapter *adapter) { int id, res = 0; + id = i2c_get_number_from_dt(adapter); + if (id >= 0) { + adapter->nr = id; + return _i2c_add_numbered_adapter(adapter); + } + retry: if (idr_pre_get(&i2c_adapter_idr, GFP_KERNEL) == 0) return -ENOMEM; @@ -983,34 +1057,9 @@ EXPORT_SYMBOL(i2c_add_adapter); */ int i2c_add_numbered_adapter(struct i2c_adapter *adap) { - int id; - int status; - if (adap->nr == -1) /* -1 means dynamically assign bus id */ return i2c_add_adapter(adap); - if (adap->nr & ~MAX_IDR_MASK) - return -EINVAL; - -retry: - if (idr_pre_get(&i2c_adapter_idr, GFP_KERNEL) == 0) - return -ENOMEM; - - mutex_lock(&core_lock); - /* "above" here means "above or equal to", sigh; - * we need the "equal to" result to force the result - */ - status = idr_get_new_above(&i2c_adapter_idr, adap, adap->nr, &id); - if (status == 0 && id != adap->nr) { - status = -EBUSY; - idr_remove(&i2c_adapter_idr, id); - } - mutex_unlock(&core_lock); - if (status == -EAGAIN) - goto retry; - - if (status == 0) - status = i2c_register_adapter(adap); - return status; + return _i2c_add_numbered_adapter(adap); } EXPORT_SYMBOL_GPL(i2c_add_numbered_adapter);