Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753900Ab1DARsJ (ORCPT ); Fri, 1 Apr 2011 13:48:09 -0400 Received: from LUNGE.MIT.EDU ([18.54.1.69]:45803 "EHLO lunge.queued.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752522Ab1DARsH (ORCPT ); Fri, 1 Apr 2011 13:48:07 -0400 Date: Fri, 1 Apr 2011 10:47:56 -0700 From: Andres Salomon To: Samuel Ortiz Cc: Grant Likely , linux-kernel@vger.kernel.org, Mark Brown , khali@linux-fr.org, ben-linux@fluff.org, Peter Korsgaard , Mauro Carvalho Chehab , David Brownell , linux-i2c@vger.kernel.org, linux-media@vger.kernel.org, netdev@vger.kernel.org, spi-devel-general@lists.sourceforge.net, Mocean Laboratories Subject: Re: [PATCH 07/19] timberdale: mfd_cell is now implicitly available to drivers Message-ID: <20110401104756.2f5c6f7a@debxo> In-Reply-To: <20110401112030.GA3447@sortiz-mobl> References: <20110202195417.228e2656@queued.net> <20110202200812.3d8d6cba@queued.net> <20110331230522.GI437@ponder.secretlab.ca> <20110401112030.GA3447@sortiz-mobl> X-Mailer: Claws Mail 3.7.6 (GTK+ 2.20.1; i486-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3265 Lines: 87 On Fri, 1 Apr 2011 13:20:31 +0200 Samuel Ortiz wrote: > Hi Grant, > > On Thu, Mar 31, 2011 at 05:05:22PM -0600, Grant Likely wrote: [...] > > Gah. Not all devices instantiated via mfd will be an mfd device, > > which means that the driver may very well expect an *entirely > > different* platform_device pointer; which further means a very high > > potential of incorrectly dereferenced structures (as evidenced by a > > patch series that is not bisectable). For instance, the xilinx ip > > cores are used by more than just mfd. > I agree. Since the vast majority of the MFD subdevices are MFD > specific IPs, I overlooked that part. The impacted drivers are the > timberdale and the DaVinci voice codec ones. Can you please provide pointers to what you're referring to? The only code that I could find that created platform devices prefixed with 'timb-' or named 'xilinx_spi' was drivers/mfd/timberdale.c. > To fix that problem I propose 2 alternatives: > > 1) When declaring the sub devices cells, the MFD driver should > specify an mfd_data_size value for sub devices that are not MFD > specific. It's the MFD driver responsibility to set the cell > properly, and the non MFD specific drivers are kept MFD agnostic. > See my patch below for the timberdale case. > > 2) Revert the mfd_get_data() call for getting sub devices platform > data pointers. That was introduced to ease the MFD cell sharing work, > so if we take this route we'll need the cs5535 MFD driver to pass its > cells as platform_data pointer. Andres, can you confirm that this > would be fine for the mfd_clone_cell() routine to keep working ? It would break mfd_clone_cell, as it uses mfd_get_cell to grab the one to clone. We could change it to accept the cell as an argument. It would also break mfd_cell_enable/disable, of course. > > Patch for solution 1: > > > drivers/mfd/mfd-core.c | 13 ++++++++++--- > drivers/mfd/timberdale.c | 11 +++++++++++ > include/linux/mfd/core.h | 1 + > drivers/i2c/busses/i2c-ocores.c | 3 +-- > drivers/i2c/busses/i2c-xiic.c | 3 +-- > drivers/net/ks8842.c | 3 +-- > drivers/spi/xilinx_spi.c | 3 +-- > 7 files changed, 26 insertions(+), 11 deletions(-) > > diff --git a/drivers/mfd/mfd-core.c b/drivers/mfd/mfd-core.c > index d01574d..8abe510 100644 > --- a/drivers/mfd/mfd-core.c > +++ b/drivers/mfd/mfd-core.c > @@ -75,9 +75,16 @@ static int mfd_add_device(struct device *parent, > int id, > pdev->dev.parent = parent; > > - ret = platform_device_add_data(pdev, cell, sizeof(*cell)); > - if (ret) > - goto fail_res; > + if (cell->mfd_data_size > 0) { > + ret = platform_device_add_data(pdev, > + cell->mfd_data, > cell->mfd_data_size); > + if (ret) > + goto fail_res; > + } else { > + ret = platform_device_add_data(pdev, cell, > sizeof(*cell)); > + if (ret) > + goto fail_res; > + } > > for (r = 0; r < cell->num_resources; r++) { > res[r].name = cell->resources[r].name; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/