From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932900Ab3BLAsS (ORCPT ); Mon, 11 Feb 2013 19:48:18 -0500 Received: from mail-gg0-f201.google.com ([209.85.161.201]:57914 "EHLO mail-gg0-f201.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932675Ab3BLAsQ (ORCPT ); Mon, 11 Feb 2013 19:48:16 -0500 From: Doug Anderson To: linux-i2c@vger.kernel.org, Wolfram Sang Cc: Mark Brown , Kukjin Kim , Olof Johansson , Thomas Abraham , Padmavathi Venna , Ben Dooks , linux-arm-kernel@lists.infradead.org, linux-samsung-soc@vger.kernel.org, Haojian Zhuang , Arnd Bergmann , Sylwester Nawrocki , Doug Anderson , linux-kernel@vger.kernel.org Subject: [PATCH v3 1/2] i2c-core: dt: Pick i2c bus number from i2c alias if present Date: Mon, 11 Feb 2013 16:48:04 -0800 Message-Id: <1360630085-26874-2-git-send-email-dianders@chromium.org> X-Mailer: git-send-email 1.8.1 In-Reply-To: <1360630085-26874-1-git-send-email-dianders@chromium.org> References: <1360630085-26874-1-git-send-email-dianders@chromium.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.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 --- Changes in v3: - Addressed Wolfram's feedback; rebased atop idr-cleanup series. Changes in v2: None drivers/i2c/i2c-core.c | 54 +++++++++++++++++++++++++++++++++++++------------- 1 file changed, 40 insertions(+), 14 deletions(-) diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c index 0b599f2..5204818 100644 --- a/drivers/i2c/i2c-core.c +++ b/drivers/i2c/i2c-core.c @@ -921,13 +921,41 @@ out_list: } /** + * __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; + + /* Handled by wrappers */ + if (WARN_ON(adap->nr == -1)) + return -EINVAL; + + if (adap->nr & ~MAX_IDR_MASK) + return -EINVAL; + + mutex_lock(&core_lock); + id = idr_alloc(&i2c_adapter_idr, adap, adap->nr, adap->nr + 1, + GFP_KERNEL); + mutex_unlock(&core_lock); + if (id < 0) + return id == -ENOSPC ? -EBUSY : id; + return i2c_register_adapter(adap); +} + +/** * 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. @@ -935,8 +963,17 @@ out_list: */ int i2c_add_adapter(struct i2c_adapter *adapter) { + struct device *dev = &adapter->dev; int res; + if (dev->of_node) { + res = of_alias_get_id(dev->of_node, "i2c"); + if (res >= 0) { + adapter->nr = res; + return __i2c_add_numbered_adapter(adapter); + } + } + mutex_lock(&core_lock); res = idr_alloc(&i2c_adapter_idr, adapter, __i2c_first_dynamic_bus_num, 0, GFP_KERNEL); @@ -974,20 +1011,9 @@ EXPORT_SYMBOL(i2c_add_adapter); */ int i2c_add_numbered_adapter(struct i2c_adapter *adap) { - int id; - if (adap->nr == -1) /* -1 means dynamically assign bus id */ return i2c_add_adapter(adap); - if (adap->nr & ~MAX_IDR_MASK) - return -EINVAL; - - mutex_lock(&core_lock); - id = idr_alloc(&i2c_adapter_idr, adap, adap->nr, adap->nr + 1, - GFP_KERNEL); - mutex_unlock(&core_lock); - if (id < 0) - return id == -ENOSPC ? -EBUSY : id; - return i2c_register_adapter(adap); + return __i2c_add_numbered_adapter(adap); } EXPORT_SYMBOL_GPL(i2c_add_numbered_adapter); -- 1.8.1