From mboxrd@z Thu Jan 1 00:00:00 1970 From: ludovic.desroches Subject: Re: [PATCH v11 0/4] AT91: replace old i2c-at91.c TWI driver Date: Wed, 29 Aug 2012 14:06:10 +0200 Message-ID: <503E05B2.2020204@atmel.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1"; Format="flowed" Content-Transfer-Encoding: quoted-printable Return-path: In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: linux-arm-kernel-bounces@lists.infradead.org Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=m.gmane.org@lists.infradead.org To: Nikolaus Voss Cc: rmallon@gmail.com, nicolas.ferre@atmel.com, linux-kernel@vger.kernel.org, balbi@ti.com, h.feurstein@gmail.com, ludovic.desroches@atmel.com, linux-i2c@vger.kernel.org, ben-linux@fluff.org, adrian.yanes@aalto.fi, linux-arm-kernel@lists.infradead.org, carsten.behling@garz-fricke.com List-Id: linux-i2c@vger.kernel.org Hi Nikolaus, Le 08/29/2012 09:28 AM, Nikolaus Voss a =E9crit : > 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. > > Changes since v11: > - corrected wrong id_entry on sam9261 twi gpio pdev > Thanks for this new version, you can add Tested-By: Ludovic Desroches for the whole series. Concerning the open drain issue, even if I don't have it on my board = your patch is correct it is needed also for chips. Once I'll have the = complete list, I'll send an additional patch. Regards Ludovic > Nikolaus Voss (4): > drivers/i2c/busses/i2c-at91.c: remove old polling 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 > > arch/arm/mach-at91/at91rm9200.c | 1 + > arch/arm/mach-at91/at91rm9200_devices.c | 9 + > arch/arm/mach-at91/at91sam9260.c | 1 + > arch/arm/mach-at91/at91sam9261.c | 1 + > arch/arm/mach-at91/at91sam9261_devices.c | 9 + > 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/at91sam9x5.c | 3 + > arch/arm/mach-at91/include/mach/at91_twi.h | 68 ---- > drivers/i2c/busses/Kconfig | 11 +- > drivers/i2c/busses/i2c-at91.c | 591 ++++++++++++++++++---= ------- > 13 files changed, 418 insertions(+), 287 deletions(-) > delete mode 100644 arch/arm/mach-at91/include/mach/at91_twi.h >