From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756280Ab2ICJuQ (ORCPT ); Mon, 3 Sep 2012 05:50:16 -0400 Received: from mail-ee0-f46.google.com ([74.125.83.46]:48140 "EHLO mail-ee0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756172Ab2ICJuN (ORCPT ); Mon, 3 Sep 2012 05:50:13 -0400 Date: Mon, 3 Sep 2012 10:50:08 +0100 From: Lee Jones To: Wolfram Sang Cc: Linus Walleij , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, STEricsson_nomadik_linux@list.st.com, linus.walleij@stericsson.com, arnd@arndb.de, linux-i2c@vger.kernel.org Subject: Re: [PATCH 3/3] i2c: nomadik: Add Device Tree support to the Nomadik I2C driver Message-ID: <20120903095001.GB5782@gmail.com> References: <1345734087-21803-1-git-send-email-lee.jones@linaro.org> <1345734087-21803-3-git-send-email-lee.jones@linaro.org> <20120831112258.GA2624@pengutronix.de> <20120831122323.GC5962@gmail.com> <20120903094448.GB11780@pengutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20120903094448.GB11780@pengutronix.de> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Sep 03, 2012 at 11:44:48AM +0200, Wolfram Sang wrote: > On Mon, Sep 03, 2012 at 11:22:28AM +0200, Linus Walleij wrote: > > On Fri, Aug 31, 2012 at 2:23 PM, Lee Jones wrote: > > > > (...) > > > static int nmk_i2c_probe(struct amba_device *adev, const struct amba_id *id) > > > { > > > int ret = 0; > > > struct nmk_i2c_controller *pdata = adev->dev.platform_data; > > > + struct device_node *np = adev->dev.of_node; > > > struct nmk_i2c_dev *dev; > > > struct i2c_adapter *adap; > > > > > > + if (np) { > > > + if (!pdata) { > > > > So, if no pdata is provided, we go on to allocate some ... > > > > > + pdata = devm_kzalloc(&adev->dev, sizeof(*pdata), GFP_KERNEL); > > > + if (!pdata) { > > > + ret = -ENOMEM; > > > + goto err_no_mem; > > > + } > > > + } > > > + /* Provide the default configuration as a base. */ > > > + pdata = &u8500_i2c; > > > > Then you just override that pointer with a pointer to the local config. > > > > > + nmk_i2c_of_probe(np, pdata); > > > + } > > > + > > > if (!pdata) > > > /* No i2c configuration found, using the default. */ > > > pdata = &u8500_i2c; > > > > This in it's entirety does not look sound. I *think* this is what you > > want to do, > > replace all of the above codde (including the last if (!pdata) clause) with: > > > > if (!pdata) { > > /* If no platform data passed in, use the default configuration as > > a base. */ > > pdata = &u8500_i2c; > > if (np) > > /* Further, if we have a DT node, override the default with this */ > > nmk_i2c_of_probe(np, pdata); > > } > > > > This makes any passed pdata take precedence, else default pdata > > complemented with DT info. Which is what we want. > > No. of_probe modifies pdata which in this case the default config which > might already be in use. So, you will get problems if you have two > instances with different configuration. So, we need to allocate memory > but copy the content of the default data. The patch above just copies > the pointer which is bogus. Agreed. I'll fixup. -- Lee Jones Linaro ST-Ericsson Landing Team Lead Linaro.org │ Open source software for ARM SoCs Follow Linaro: Facebook | Twitter | Blog