Make sure the I2C write queue is empty before leaving the mxs_i2c_write().
If we start and I2C write and only wait for ACK, the MXS I2C IP block may
enter next operation while still processing the write aftermath internally.
This will in turn disrupt one or more subsequent transfer(s).
A testcase for this issue is as such. This testcase is also interesting because
the first I2C_WRITE which becomes disruptive happens in the 'i2c read' command.
The 'i2c read' command first uses I2C_WRITE to send I2C address of the chip and
then uses I2C_READ to read data from the chip. After this command completes, the
'i2c probe' will use sequence of I2C_WRITE commands to probe the I2C bus. The
problem is that the first I2C_WRITE disrupted the I2C IP block operation and
this sideeffect propagates all the way to this next I2C_WRITE used by the 'i2c
probe' call. The result is the 'i2c probe' receives an ACK on I2C address 0x00,
even if this ACK was owned by the previous I2C_WRITE operation. Note that the
'i2c read' command must read from a valid I2C chip address.
Wrong:
> i2c probe
Valid chip addresses: 50 51
> i2c read 0x50 0x0.2 0x10 0x42000000
> i2c probe
Valid chip addresses: 00 50 51
With this patch
> i2c probe
Valid chip addresses: 50 51
> i2c read 0x50 0x0.2 0x10 0x42000000
> i2c probe
Valid chip addresses: 50 51
Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Heiko Schocher <hs@denx.de>
Cc: Fabio Estevam <festevam@gmail.com>
The endless waiting for a bit to be set can cause a hang, add a timeout
so we prevent such situation. A testcase for such a hang is below. The
testcase assumes a device to be present at address 0x50 and a device to
NOT be present at address 0x42 . Also note that the "sleep 1" induced
delays are imperative for this bug to manifest .
i2c read 0x42 0x0.2 0x10 0x42000000 ; sleep 1 ; \
i2c read 0x50 0x0.2 0x10 0x42000000 ; sleep 1 ; \
i2c read 0x42 0x0.2 0x10 0x42000000
The expected result of the above command is:
Error reading the chip.
Error reading the chip.
While without this patch, we observe a hang in the last read from 0x42
precisely when waiting for this bit to be set.
Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Fabio Estevam <fabio.estevam@freescale.com>
Cc: Heiko Schocher <hs@denx.de>
Cc: Stefano Babic <sbabic@denx.de>
The local functions in the mxs i2c driver are not marked static, make it so.
Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Stefano Babic <sbabic@denx.de>
Cc: Heiko Schocher <hs@denx.de>
This algorithm computes the values of TIMING{0,1,2} registers for the
MX28 I2C block. This algorithm was derived by using a scope, but the
result seems correct.
The resulting values programmed into the registers do not correlate
with the contents in datasheet. When using the values from the datasheet,
the I2C clock were completely wrong.
Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Stefano Babic <sbabic@denx.de>
Cc: Fabio Estevam <fabio.estevam@freescale.com>
Cc: Wolfgang Denk <wd@denx.de>
The I2C block reset configures the I2C bus speed to strange value.
Read the I2C speed from the block before reseting the block and
restore it afterwards, so the I2C operates correctly. This issue
can be replicated by doing unsuccessful I2C transfer, after such
transfer finishes, the I2C block clock speed is misconfigured.
Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Heiko Schocher <hs@denx.de>
Cc: Fabio Estevam <fabio.estevam@freescale.com>
According to FSL, the value in the TIMING2 register shall be 0x00300030
instead of what's written in the datasheet. This new value correlates
with older STMP36xx datasheet. Issues were detected in Linux when this
register was misconfigured, so write this correct value.
Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Stefano Babic <sbabic@denx.de>
Cc: Fabio Estevam <fabio.estevam@freescale.com>
Use i2c_set_bus_speed() in i2c_init() within the mxs i2c driver
to avoid duplication of code.
Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Stefano Babic <sbabic@denx.de>
Cc: Fabio Estevam <fabio.estevam@freescale.com>
This patch implements the setup and retrieval functions for the I2C
bus speed on the MXS I2C IP.
Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Stefano Babic <sbabic@denx.de>
Cc: Fabio Estevam <fabio.estevam@freescale.com>
This patch pulls out the I2C speed setup from the i2c_init() call
and implements the bus configuration lookup table with register
values that needs to be programmed into the I2C IP to run at
particular speed.
This patch is a first step towards implementing run-time I2C bus
speed configuration for the MXS I2C IP.
Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Stefano Babic <sbabic@denx.de>
Cc: Fabio Estevam <fabio.estevam@freescale.com>
The sys_proto.h functions (except the boot modes) are compatible with
i.MX233 and i.MX28 so we use 'mxs' prefix for its methods.
Signed-off-by: Otavio Salvador <otavio@ossystems.com.br>
Large EEPROMs, e.g. 24lc32, need 2 byte to address the internal memory.
These devices require that the high byte of the internal address has to be
written first.
The mxs_i2c driver currently writes the address' low byte first.
The following patch fixes the byte order of the internal address that should
be written to the I2C device.
Signed-off-by: Torsten Fleischer <to-fleischer@t-online.de>
CC: Marek Vasut <marex@denx.de>
CC: Stefano Babic <sbabic@denx.de>
CC: Fabio Estevam <fabio.estevam@freescale.com>
Acked-by: Marek Vasut <marex@denx.de>
Acked-by: Stefano Babic <sbabic@denx.de>
