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    SubjectRe: [PATCH v7 0/5] AT91: replace broken TWI driver i2c-at91.c

    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
    >
    > --
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    --
    Ben Dooks, ben@fluff.org, http://www.fluff.org/ben/

    Large Hadron Colada: A large Pina Colada that makes the universe disappear.



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