Messages in this thread | | | From | Nikolaus Voss <> | Date | Mon, 19 Mar 2012 16:07:10 +0100 | Subject | [PATCH v9 0/4] AT91: replace broken TWI driver i2c-at91.c |
| |
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@weinmann.de> Reviewed-by: Felipe Balbi <balbi@ti.com> Tested-by: Hubert Feurstein <h.feurstein@gmail.com>
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
| |