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From: Nikolaus Voss <n.voss-+umVssTZoCsb1SvskN2V4Q@public.gmane.org>
To: linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org,
	linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Cc: ben-linux-elnMNo+KYs3YtjvyW6yDsg@public.gmane.org,
	khali-PUYAD+kWke1g9hUCZPvPmw@public.gmane.org,
	nicolas.ferre-AIFe0yeh4nAAvxtiuMwx3w@public.gmane.org,
	rmallon-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org,
	balbi-l0cyMroinI0@public.gmane.org
Subject: [PATCH v4 0/4] AT91: replace broken TWI driver i2c-at91.c
Date: Wed, 9 Nov 2011 16:52:01 +0100	[thread overview]
Message-ID: <cover.1320853921.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.

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 (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 +
 arch/arm/mach-at91/include/mach/at91_twi.h |   68 ----
 drivers/i2c/busses/Kconfig                 |   11 +-
 drivers/i2c/busses/i2c-at91.c              |  476 +++++++++++++++++-----------
 drivers/i2c/busses/i2c-at91.h              |   80 +++++
 7 files changed, 371 insertions(+), 274 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

WARNING: multiple messages have this Message-ID (diff)
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 v4 0/4] AT91: replace broken TWI driver i2c-at91.c
Date: Wed, 9 Nov 2011 16:52:01 +0100	[thread overview]
Message-ID: <cover.1320853921.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.

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 (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 +
 arch/arm/mach-at91/include/mach/at91_twi.h |   68 ----
 drivers/i2c/busses/Kconfig                 |   11 +-
 drivers/i2c/busses/i2c-at91.c              |  476 +++++++++++++++++-----------
 drivers/i2c/busses/i2c-at91.h              |   80 +++++
 7 files changed, 371 insertions(+), 274 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


             reply	other threads:[~2011-11-09 15:52 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-11-09 15:52 Nikolaus Voss [this message]
2011-11-09 15:52 ` [PATCH v4 0/4] AT91: replace broken TWI driver i2c-at91.c Nikolaus Voss
     [not found] ` <cover.1320853921.git.n.voss-+umVssTZoCsb1SvskN2V4Q@public.gmane.org>
2011-11-08 10:49   ` [PATCH v4 1/4] drivers/i2c/busses/i2c-at91.c: remove broken driver Nikolaus Voss
2011-11-08 10:49     ` Nikolaus Voss
2011-11-08 10:49 ` [PATCH v4 2/4] drivers/i2c/busses/i2c-at91.c: add new driver Nikolaus Voss
     [not found]   ` <fc7ccca66f0ffea1aa9c0409162b4a66974c46b3.1320853921.git.n.voss-+umVssTZoCsb1SvskN2V4Q@public.gmane.org>
2011-11-09 19:59     ` Felipe Balbi
2011-11-09 19:59       ` Felipe Balbi
2011-11-09 19:59       ` Felipe Balbi
     [not found]       ` <20111109195925.GB17406-UiBtZHVXSwEVvW8u9ZQWYwjfymiNCTlR@public.gmane.org>
2011-11-09 22:22         ` Ryan Mallon
2011-11-09 22:22           ` Ryan Mallon
2011-11-09 22:22           ` Ryan Mallon
2011-11-08 11:09 ` [PATCH v4 4/4] Add lookup entries for twi_clk for devices with more than one TWI port Nikolaus Voss
2011-11-08 11:11 ` [PATCH v4 3/4] G45 TWI: remove open drain setting for twi function gpios Nikolaus Voss

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