From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753443Ab1KWXcs (ORCPT ); Wed, 23 Nov 2011 18:32:48 -0500 Received: from trinity.fluff.org ([89.16.178.74]:44043 "EHLO trinity.fluff.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751726Ab1KWXcr (ORCPT ); Wed, 23 Nov 2011 18:32:47 -0500 Date: Wed, 23 Nov 2011 23:32:38 +0000 From: Ben Dooks To: Nikolaus Voss Cc: linux-i2c@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, ben-linux@fluff.org, carsten.behling@garz-fricke.com Subject: Re: [PATCH v7 0/5] AT91: replace broken TWI driver i2c-at91.c Message-ID: <20111123233238.GL19115@trinity.fluff.org> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Disclaimer: These are my views alone. X-URL: http://www.fluff.org/ User-Agent: Mutt/1.5.18 (2008-05-17) X-SA-Exim-Connect-IP: X-SA-Exim-Mail-From: ben@trinity.fluff.org X-SA-Exim-Scanned: No (on trinity.fluff.org); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Nov 23, 2011 at 04:35:55PM +0100, Nikolaus Voss wrote: > The old driver has two main deficencies: > i) No repeated start (Sr) condiction is possible, this makes it unusable > e.g. for most SMBus transfers. > ii) I/O was done with polling/busy waiting what caused over-/underruns > even at light system loads and clock speeds. > > The new driver overcomes these deficencies and in addition allows for > more than one TWI interface. > > A remaining limitation is the fact, that only one repeated start is > possible (two concatenated messages). This limitation is imposed by > the hardware. However, this should not be a problem as all common > i2c-client communication does not rely on more than one repeated start. > > v7: Patch 4/5: i) fix bug if internal address > 1 byte > ii) send stop when len == 1 > (both reported by Carsten Behling) > v6: Patch 5/5: support for I2C_SMBUS_BLOCK_DATA transfers. > Better use of clk_(un)prepare(). > More sensible transfer timeout. > v5: Another round of review comments from Ryan Mallon, Felipe Balbi > and Russell King: convert twi clk to use .dev_id, cleanups > v4: Integrated more review comments from Ryan Mallon and Felipe Balbi: > Moved register include file to local include, code cleanups > v3: Integrated review comments from Ryan Mallon and Felipe Balbi > v2: Fixed whitespace issue > > Nikolaus Voss (5): > drivers/i2c/busses/i2c-at91.c: remove broken driver > Replace clk_lookup.con_id with clk_lookup.dev_id entries for twi clk > drivers/i2c/busses/i2c-at91.c: add new driver > G45 TWI: remove open drain setting for twi function gpios > i2c-at91.c: add SMBUS_READ_BLOCK_DATA functionality Is the original driver so broken that the two could not co-exist, or are we making so many changes that there's no point in keeping the original one? > arch/arm/mach-at91/at91cap9.c | 1 + > arch/arm/mach-at91/at91rm9200.c | 1 + > arch/arm/mach-at91/at91sam9260.c | 1 + > arch/arm/mach-at91/at91sam9261.c | 1 + > arch/arm/mach-at91/at91sam9263.c | 1 + > arch/arm/mach-at91/at91sam9g45.c | 2 + > arch/arm/mach-at91/at91sam9g45_devices.c | 6 - > arch/arm/mach-at91/at91sam9rl.c | 2 + > arch/arm/mach-at91/include/mach/at91_twi.h | 68 ---- > drivers/i2c/busses/Kconfig | 11 +- > drivers/i2c/busses/i2c-at91.c | 529 +++++++++++++++++----------- > drivers/i2c/busses/i2c-at91.h | 80 +++++ > 12 files changed, 408 insertions(+), 295 deletions(-) > delete mode 100644 arch/arm/mach-at91/include/mach/at91_twi.h > create mode 100644 drivers/i2c/busses/i2c-at91.h > > -- > 1.7.5.4 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-i2c" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- Ben Dooks, ben@fluff.org, http://www.fluff.org/ben/ Large Hadron Colada: A large Pina Colada that makes the universe disappear.