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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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