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From: Nikolaus Voss <n.voss-+umVssTZoCsb1SvskN2V4Q@public.gmane.org>
To: linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org,
	linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Cc: nicolas.ferre-AIFe0yeh4nAAvxtiuMwx3w@public.gmane.org,
	ben-linux-elnMNo+KYs3YtjvyW6yDsg@public.gmane.org,
	balbi-l0cyMroinI0@public.gmane.org,
	h.feurstein-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org,
	rmallon-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org
Subject: [PATCH v9 0/4] AT91: replace broken TWI driver i2c-at91.c
Date: Mon, 19 Mar 2012 16:07:10 +0100	[thread overview]
Message-ID: <cover.1322479017a.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.

Signed-off-by: Nikolaus Voss <n.voss-+umVssTZoCsb1SvskN2V4Q@public.gmane.org>
Reviewed-by: Felipe Balbi <balbi-l0cyMroinI0@public.gmane.org>
Tested-by: Hubert Feurstein <h.feurstein-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>

v9: i) merge i2c-at91.c patches to single patch
    ii) rewrite cwgr reg after timeout to reenable the right twi clock
v8: i) remove local include
    ii) remove cpu_is_rm9200() and put twi hw bug info in platform_device
    iii) use readl/writel_relaxed instead of __raw_readl/writel
v7: i) fix bug if internal address > 1 byte
    ii) send stop when len == 1 (both reported by Carsten Behling)
v6: 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 (4):
  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

 arch/arm/mach-at91/at91cap9.c              |    1 +
 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/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              |  561 +++++++++++++++++-----------
 12 files changed, 373 insertions(+), 291 deletions(-)
 delete mode 100644 arch/arm/mach-at91/include/mach/at91_twi.h

-- 
1.7.5.4

             reply	other threads:[~2012-03-19 15:07 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-03-19 15:07 Nikolaus Voss [this message]
2011-11-08 10:49 ` [PATCH v9 1/4] drivers/i2c/busses/i2c-at91.c: remove broken driver Nikolaus Voss
2011-11-08 10:49 ` [PATCH v9 3/4] drivers/i2c/busses/i2c-at91.c: add new driver Nikolaus Voss
     [not found]   ` <201203191534.q2JFYl1b012744-vb1CFJ/PVqUnDeILM3HATdG/hX4sBvbD@public.gmane.org>
2012-04-13 10:17     ` Hubert Feurstein
     [not found]       ` <CAFfN3gWCu5RnKb6dK4YMCAhpkfLncYdk1Cwqxb3wxMVznSiSFQ-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2012-04-13 10:39         ` Felipe Balbi
     [not found]           ` <20120413103937.GH7154-S8G//mZuvNWo5Im9Ml3/Zg@public.gmane.org>
2012-04-13 11:44             ` [PATCH] i2c-at91: fix data-loss issue Hubert Feurstein
     [not found]               ` <1334317476-10044-1-git-send-email-h.feurstein-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2012-04-13 22:06                 ` Ryan Mallon
2012-04-16  7:30               ` Voss, Nikolaus
     [not found]                 ` <EF2E73589CA71846A15D0B2CDF79505D0905D5A1AA-qhZVaJ2D3XF9OWT4OSQXE9BPR1lH4CV8@public.gmane.org>
2012-04-16  9:27                   ` Hubert Feurstein
2012-04-18 14:39                 ` Wolfram Sang
2012-04-21 19:33                   ` Adrian Yanes
2012-04-23  5:39                     ` Voss, Nikolaus
2012-04-23  6:24                       ` Adrian Yanes
2012-04-25  5:26                         ` Adrian Yanes
     [not found] ` <cover.1322479017a.git.n.voss-+umVssTZoCsb1SvskN2V4Q@public.gmane.org>
2011-11-08 11:09   ` [PATCH v9 2/4] Replace clk_lookup.con_id with clk_lookup.dev_id entries for twi clk Nikolaus Voss
2011-11-08 11:11 ` [PATCH v9 4/4] G45 TWI: remove open drain setting for twi function gpios Nikolaus Voss

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