It can be optimised out by the compiler otherwise resulting
in obscure errors like a board not booting.
This has been documented in README since 2006 when these were
first fixed up for GCC 4.x.
Signed-off-by: John Rigby <john.rigby@linaro.org>
Fix some additional places.
Signed-off-by: Wolfgang Denk <wd@denx.de>
Acked-By: Albert ARIBAUD <albert.aribaud@free.fr>
On OMAP36/37XX the standard on chip pullups are not sufficient to
ensure proper i2c operation without external pullups or switching
to high speed mode and enabling special on chip pullups.
This is an issue for Beagle xM, which does not have external pullups
on the expansion board i2c lines.
The issue manifests itself as an AL (arbitration lost) error when
probing for a non-existent device (i.e. on a Beagle xM with no expansion
boards attached). This issue does not occur on expansion boards that
include pullups or on Overo 37XX COM's since they include pull-ups.
This patch fixes the issue by checking for the AL bit in the i2c_probe
function.
Signed-off-by: Steve Sakoman <steve.sakoman@linaro.org>
This patch removes the "magic number" delays and instead
monitors state changes in the status register bits.
Signed-off-by: Steve Sakoman <steve.sakoman@linaro.org>
Tested-by: Heiko Schocher <hs@denx.de>
This patch removes the "magic number" delays and instead
monitors state changes in the status register bits.
Signed-off-by: Steve Sakoman <steve.sakoman@linaro.org>
Tested-by: Heiko Schocher <hs@denx.de>
This patch removes the "magic number" delays and instead
monitors state changes in the status register bits.
Signed-off-by: Steve Sakoman <steve.sakomanlinaro.org>
Tested-by: Heiko Schocher <hs@denx.de>
This patch matches the poll interval (1 millisecond) and timeout (1 second)
used in the linux driver. It also adds a return value of 0 in the event of
a timeout error and cleans up some formatting errors in that section of the
code.
Signed-off-by: Steve Sakoman <steve.sakoman@linaro.org>
Tested-by: Heiko Schocher <hs@denx.de>
This patch modifies the init routine to follow the TRM
recommendations. It also modifies the i2c_read_byte function
to reflect subtle differences between the i2c controller in
OMAP3 and OMAP4.
Signed-off-by: Steve Sakoman <steve@sakoman.com>
Acked-by: Nishanth Menon <menon.nishanth@gmail.com>
Acked-by: Heiko Schocher <hs@denx.de>
Signed-off-by: Sandeep Paulraj <s-paulraj@ti.com>
This patch modifies the omap24xx driver so that it will also work with OMAP4.
Signed-off-by: Steve Sakoman <steve@sakoman.com>
Signed-off-by: Sandeep Paulraj <s-paulraj@ti.com>
Add support to use second and third I2C bus, too.
Bus 0 is still the default, but by calling i2c_set_bus_num(1/2) before doing
I2C accesses, code can switch to bus 1 and 2, too. Don't forget to switch
back afterwards, then.
Signed-off-by: Dirk Behme <dirk.behme@googlemail.com>
This problem is seen on Zoom1 and Zoom2 in the startup and
when i2c probe is used
Before :
In: serial
Out: serial
Err: serial
timed out in wait_for_bb: I2C_STAT=1000
timed out in wait_for_bb: I2C_STAT=1000
timed out in wait_for_bb: I2C_STAT=1000
timed out in wait_for_pin: I2C_STAT=1000
I2C read: I/O error
timed out in wait_for_bb: I2C_STAT=1000
timed out in wait_for_bb: I2C_STAT=1000
Die ID #327c00020000000004013ddd05026013
Hit any key to stop autoboot: 0
OMAP3 Zoom1# i2c probe
Valid chip addresses:timed out in wait_for_bb: I2C_STAT=1000
02 03 04 05 06 07 08 09 0A 0B 0C 0D <snip>
After :
In: serial
Out: serial
Err: serial
Die ID #327c00020000000004013ddd05026013
Hit any key to stop autoboot: 0
OMAP3 Zoom1# i2c probe
Valid chip addresses: 48 49 4A 4B
The addresses are for the twl4030.
The prescalar that converts the function clock to the sampling
clock is hardcoded to 0. The reference manual recommends 7
if the function clock is 96MHz.
Instead of just changing the hardcoded values, the prescalar
is calculated from the value I2C_IP_CLK.
The i2c #defines are in kHz. The speed passed into the
i2c init routine is in Hz. To be consistent, change the
defines to be in Hz.
The timing calculations are based on what is done in the
linux 2.6.30 kernel in drivers/i2c/buses/i2c_omap.c as
apposed to what is done in TRM.
The major variables in the timing caculations are
specified as #defines that can be overriden as required.
The variables and their defaults are
I2C_IP_CLK SYSTEM_CLOCK_96
I2C_INTERNAL_SAMPLING_CLK 19200000
I2C_FASTSPEED_SCLL_TRIM 6
I2C_FASTSPEED_SCLH_TRIM 6
I2C_HIGHSPEED_PHASE_ONE_SCLL_TRIM I2C_FASTSPEED_SCLL_TRIM
I2C_HIGHSPEED_PHASE_ONE_SCLH_TRIM I2C_FASTSPEED_SCLH_TRIM
I2C_HIGHSPEED_PHASE_TWO_SCLL_TRIM I2C_FASTSPEED_SCLL_TRIM
I2C_HIGHSPEED_PHASE_TWO_SCLH I2C_FASTSPEED_SCLH_TRIM
This was runtime verified on Zoom1, Zoom2, Beagle and Overo.
The 400kHz and 3.4M cases were verifed on test Zoom1,
Zoom2, Beagle and Overo configurations.
Testing for omap2 will be done in a second step as Nishanth
and Jean-Christophe commented.
Signed-off-by: Tom Rix <Tom.Rix@windriver.com>
Acked-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Acked-by: Heiko Schocher <hs@denx.de>
John Rigby