Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754001Ab1BVKq7 (ORCPT ); Tue, 22 Feb 2011 05:46:59 -0500 Received: from mail-out.m-online.net ([212.18.0.9]:57217 "EHLO mail-out.m-online.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753927Ab1BVKq6 (ORCPT ); Tue, 22 Feb 2011 05:46:58 -0500 X-Auth-Info: j1aBlrnnSYXO85LeNla0Tv2gkcdaE430dz9+pfFLav4= Message-ID: <4D639493.1060601@grandegger.com> Date: Tue, 22 Feb 2011 11:48:51 +0100 From: Wolfgang Grandegger User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.1.12) Gecko/20100907 Fedora/3.0.7-1.fc12 Thunderbird/3.0.7 MIME-Version: 1.0 To: Samuel Ortiz CC: Subhasish Ghosh , sachi@mistralsolutions.com, davinci-linux-open-source@linux.davincidsp.com, nsekhar@ti.com, open list , m-watkins@ti.com, linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH v2 01/13] mfd: pruss mfd driver. References: <1297435892-28278-1-git-send-email-subhasish@mistralsolutions.com> <1297435892-28278-2-git-send-email-subhasish@mistralsolutions.com> <20110221163027.GF10686@sortiz-mobl> <37B3755C4AE64BAA805DFBAEBDC3D9E4@subhasishg> <20110222103127.GC30279@sortiz-mobl> In-Reply-To: <20110222103127.GC30279@sortiz-mobl> X-Enigmail-Version: 1.0.1 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3578 Lines: 110 On 02/22/2011 11:31 AM, Samuel Ortiz wrote: > Hi Subhasish, > > On Tue, Feb 22, 2011 at 11:13:38AM +0530, Subhasish Ghosh wrote: >> Thank you for your comments. > No problem. > >>>> diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig >>>> index fd01836..6c437df 100644 >>>> --- a/drivers/mfd/Kconfig >>>> +++ b/drivers/mfd/Kconfig >>>> @@ -81,6 +81,16 @@ config MFD_DM355EVM_MSP >>>> boards. MSP430 firmware manages resets and power sequencing, >>>> inputs from buttons and the IR remote, LEDs, an RTC, and more. >>>> >>>> +config MFD_DA8XX_PRUSS >>>> + tristate "Texas Instruments DA8XX PRUSS support" >>>> + depends on ARCH_DAVINCI && ARCH_DAVINCI_DA850 >>> Why are we depending on those ? >> >> SG -- The PRUSS core in only available within DA850 and DA830, >> DA830 support is not yet implemented. > Sure, but if there are no actual code dependencies, I'd like to get rid of > those depends. > >>>> +u32 pruss_disable(struct device *dev, u8 pruss_num) >>>> +{ >>>> + struct da8xx_pruss *pruss = dev_get_drvdata(dev->parent); >>>> + da8xx_prusscore_regs h_pruss; >>>> + u32 temp_reg; >>>> + >>>> + if (pruss_num == DA8XX_PRUCORE_0) { >>>> + /* Disable PRU0 */ >>>> + h_pruss = (da8xx_prusscore_regs) >>>> + ((u32) pruss->ioaddr + 0x7000); >>> So it seems you're doing this in several places, and I have a few >>> comments: >>> >>> - You don't need the da8xx_prusscore_regs at all. >>> - Define the register map through a set of #define in your header file. >>> - Use a static routine that takes the core number and returns the >>> register map >>> offset. >>> >>> Then routines like this one will look a lot more readable. >> >> SG -- There are a huge number of PRUSS registers. A lot of them are >> reserved and are expected to change as development on the >> controller is still ongoing. > First of all, from what I read in your patch you're only using the CONTROL > offset. > >> If we use #defines to plot >> all the registers, then first, there are too many array type >> registers which will need to be duplicated. > What I'm expecting is a small set of defines for the register offsets. You > have 13 fields in your da8xx_prusscore_regs, you only need to define 13 > register offsets. > > So, if you have a: > > static u32 reg_offset(struct device *dev, u8 pru_num) > { > struct da8xx_pruss *pru = dev_get_drvdata(dev->parent); > > switch (pru_num) { > case DA8XX_PRUCORE_0: > return (u32) pru->ioaddr + 0x7000; > case DA8XX_PRUCORE_1: > return (u32) pru->ioaddr + 0x7800; > default: > return 0; > } > > > then routines like pruss_enable (which should return an int, btw) would look > like: > > int pruss_enable(struct device *dev, u8 pruss_num) > { > u32 offset = reg_offset(dev, pruss_num); > > if (offset == 0) > return -EINVAL; > > __raw_writel(DA8XX_PRUCORE_CONTROL_RESETVAL, > offset + PRU_CORE_CONTROL); > > return 0; > } All registers are memory mapped and could nicely be described by structures (and sub-structures). Therefore we asked to considerer structs, at least for the Pruss SocketCAN drivers. That would result in much much clearer and better readable code. The code above would shrink to: __raw_writel(DA8XX_PRUCORE_CONTROL_RESETVAL, &prucore[pruss_num].control); And proper type checking would be ensured as well. Wolfgang. -- 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/