From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756592Ab2KOIhe (ORCPT ); Thu, 15 Nov 2012 03:37:34 -0500 Received: from vsp-authed02.binero.net ([195.74.38.226]:52612 "HELO vsp-authed-01-02.binero.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1755835Ab2KOIhd (ORCPT ); Thu, 15 Nov 2012 03:37:33 -0500 Message-ID: <50A4A9A9.5050903@gaisler.com> Date: Thu, 15 Nov 2012 09:36:57 +0100 From: Andreas Larsson User-Agent: Mozilla/5.0 (X11; Linux i686; rv:16.0) Gecko/20121028 Thunderbird/16.0.2 MIME-Version: 1.0 To: Peter Korsgaard CC: Wolfram Sang , Ben Dooks , linux-i2c@vger.kernel.org, Grant Likely , devicetree-discuss@lists.ozlabs.org, linux-kernel@vger.kernel.org, software@gaisler.com Subject: Re: [PATCH v3 2/2] i2c: i2c-ocores: Add support for the GRLIB port of the controller and custom getreg and setreg functions References: <1352834727-16368-1-git-send-email-andreas@gaisler.com> <1352834727-16368-3-git-send-email-andreas@gaisler.com> <87sj8d86lo.fsf@dell.be.48ers.dk> In-Reply-To: <87sj8d86lo.fsf@dell.be.48ers.dk> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2012-11-13 23:45, Peter Korsgaard wrote: >>>>>> "Andreas" == Andreas Larsson writes: > > Hi, > > Andreas> The registers in the GRLIB port of the controller are 32-bit > Andreas> and in big endian byte order. The PRELOW and PREHIGH registers > Andreas> are merged into one register. The subsequent registers have > Andreas> their offset decreased accordingly. Hence the register access > Andreas> needs to be handled in a non-standard manner using custom > Andreas> getreg and setreg functions. > > Andreas> @@ -257,6 +300,14 @@ static int ocores_i2c_of_probe(struct platform_device *pdev, > > Andreas> of_property_read_u32(pdev->dev.of_node, "reg-io-width", > Andreas> &i2c->reg_io_width); > Andreas> + > Andreas> + if (of_device_is_compatible(pdev->dev.of_node, > Andreas> + "aeroflexgaisler,i2cmst")) { > Andreas> + dev_dbg(&pdev->dev, "GRLIB variant of i2c-ocores\n"); > Andreas> + i2c->setreg = oc_setreg_grlib; > Andreas> + i2c->getreg = oc_getreg_grlib; > Andreas> + } > Andreas> + > > Please also update the bindings documentation under > Documentation/devicetree/bindings/i2c. Sure! > With this core you need to add both aeroflexgaisler,i2cmst and > opencores,i2c-ocores to the compatible property, but the grlib variant > is NOT compatible with i2c-ocores, so that's not really nice. > > Adding a type define (TYPE_OCORES / TYPE_GRLIB) and a 2nd of_device_id > entry with .data = TYPE_GRLIB, and then using that in the probe routine > would be nicer. Have a look at i2c-at91.c for an example of a driver > doing something like that. Yes, that is a good idea. Do you think casting to and from void * in the following solution is too ugly and rather have a struct pointed to, or do you think that would be unnecessary? static struct of_device_id ocores_i2c_match[] = { { .compatible = "opencores,i2c-ocores", .data = (void *)TYPE_OCORES, }, { .compatible = "aeroflexgaisler,i2cmst", .data = (void *)TYPE_GRLIB, }, {}, }; MODULE_DEVICE_TABLE(of, ocores_i2c_match); static int ocores_i2c_get_type(struct platform_device *pdev) { const struct of_device_id *match; match = of_match_node(ocores_i2c_match, pdev->dev.of_node); if (match) return (int)match->data; else return TYPE_OCORES; } Cheers, Andreas