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From: Nikolaus Voss <n.voss@weinmann.de>
To: linux-i2c@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org
Cc: ben-linux@fluff.org, khali@linux-fr.org, nicolas.ferre@atmel.com,
	rmallon@gmail.com, balbi@ti.com
Subject: [PATCH V3 0/4] AT91: replace broken TWI driver i2c-at91.c
Date: Tue, 8 Nov 2011 12:52:22 +0100	[thread overview]
Message-ID: <cover.1320753142.git.n.voss@weinmann.de> (raw)

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.

V3: Integrated review comments from Ryan Mallon and Felipe Balbi
V2: Fixed whitespace issue

Nikolaus Voss (4):
  drivers/i2c/busses/i2c-at91.c: remove broken driver
  drivers/i2c/busses/i2c-at91.c: add new driver
  G45 TWI: remove open drain setting for twi function gpios
  Add lookup entries for twi_clk for devices with more than one TWI
    port

 arch/arm/mach-at91/at91sam9g45.c         |    2 +
 arch/arm/mach-at91/at91sam9g45_devices.c |    6 -
 arch/arm/mach-at91/at91sam9rl.c          |    2 +
 drivers/i2c/busses/Kconfig               |   11 +-
 drivers/i2c/busses/i2c-at91.c            |  453 +++++++++++++++++++-----------
 5 files changed, 292 insertions(+), 182 deletions(-)

-- 
1.7.5.4


             reply	other threads:[~2011-11-08 14:15 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-11-08 11:52 Nikolaus Voss [this message]
2011-11-08 10:49 ` [PATCH V3 1/4] drivers/i2c/busses/i2c-at91.c: remove broken driver Nikolaus Voss
2011-11-08 14:36   ` Felipe Balbi
2011-11-08 10:49 ` [PATCH V3 2/4] drivers/i2c/busses/i2c-at91.c: add new driver Nikolaus Voss
2011-11-08 14:41   ` Felipe Balbi
2011-11-08 15:15     ` Nicolas Ferre
2011-11-08 15:23       ` Felipe Balbi
2011-11-08 18:29         ` Russell King - ARM Linux
2011-11-08 18:44           ` Felipe Balbi
2011-11-08 18:55             ` Russell King - ARM Linux
2011-11-08 19:02               ` Felipe Balbi
2011-11-08 19:39                 ` Russell King - ARM Linux
2011-11-08 19:58                   ` Felipe Balbi
2011-11-08 21:14                     ` Russell King - ARM Linux
2011-11-08 15:35     ` Voss, Nikolaus
2011-11-08 15:40       ` Felipe Balbi
2011-11-08 15:49         ` Voss, Nikolaus
2011-11-08 18:06           ` Felipe Balbi
2011-11-08 22:50   ` Ryan Mallon
2011-11-09 16:01     ` Voss, Nikolaus
2011-11-09 19:11       ` Russell King - ARM Linux
2011-11-08 23:58   ` Ryan Mallon
2011-11-08 11:09 ` [PATCH V3 4/4] Add lookup entries for twi_clk for devices with more than one TWI port Nikolaus Voss
2011-11-08 11:11 ` [PATCH V3 3/4] G45 TWI: remove open drain setting for twi function gpios Nikolaus Voss

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