linux-stable.git/drivers/i2c, branch linux-3.17.y

i2c: cadence: Set the hardware time-out register to maximum value

2014-12-16T17:37:07+00:00

commit 681d15a0f527af7ab3a783e1037de86fbcb136ac upstream.

Cadence I2C controller has bug wherein it generates invalid read transactions
after timeout in master receiver mode. This driver does not use the HW
timeout and this interrupt is disabled but the feature itself cannot be
disabled. Hence, this patch writes the maximum value (0xFF) to this register.
This is one of the workarounds to this bug and it will not avoid the issue
completely but reduces the chances of error.

Signed-off-by: Vishnu Motghare 
Signed-off-by: Harini Katakam 
Signed-off-by: Wolfram Sang 
Signed-off-by: Greg Kroah-Hartman

i2c: davinci: generate STP always when NACK is received

2014-12-16T17:37:07+00:00

commit 9ea359f7314132cbcb5a502d2d8ef095be1f45e4 upstream.

According to I2C specification the NACK should be handled as follows:
"When SDA remains HIGH during this ninth clock pulse, this is defined as the Not
Acknowledge signal. The master can then generate either a STOP condition to
abort the transfer, or a repeated START condition to start a new transfer."
[I2C spec Rev. 6, 3.1.6: http://www.nxp.com/documents/user_manual/UM10204.pdf]

Currently the Davinci i2c driver interrupts the transfer on receipt of a
NACK but fails to send a STOP in some situations and so makes the bus
stuck until next I2C IP reset (idle/enable).

For example, the issue will happen during SMBus read transfer which
consists from two i2c messages write command/address and read data:

S Slave Address Wr A Command Code A Sr Slave Address Rd A D1..Dn A P
<--- write -----------------------> <--- read --------------------->

The I2C client device will send NACK if it can't recognize "Command Code"
and it's expected from I2C master to generate STP in this case.
But now, Davinci i2C driver will just exit with -EREMOTEIO and STP will
not be generated.

Hence, fix it by generating Stop condition (STP) always when NACK is received.

This patch fixes Davinci I2C in the same way it was done for OMAP I2C
commit cda2109a26eb ("i2c: omap: query STP always when NACK is received").

Reviewed-by: Uwe Kleine-König 
Reported-by: Hein Tibosch 
Signed-off-by: Grygorii Strashko 
Signed-off-by: Wolfram Sang 
Signed-off-by: Greg Kroah-Hartman

i2c: omap: fix i207 errata handling

2014-12-16T17:37:07+00:00

commit ccfc866356674cb3a61829d239c685af6e85f197 upstream.

commit 6d9939f651419a63e091105663821f9c7d3fec37 (i2c: omap: split out [XR]DR
and [XR]RDY) changed the way how errata i207 (I2C: RDR Flag May Be Incorrectly
Set) get handled. 6d9939f6514 code doesn't correspond to workaround provided by
errata.

According to errata ISR must filter out spurious RDR before data read not after.
ISR must read RXSTAT to get number of bytes available to read. Because RDR
could be set while there could no data in the receive FIFO.

Restored pre 6d9939f6514 way of handling errata.

Found by code review. Real impact haven't seen.
Tested on Beagleboard XM C.

Signed-off-by: Alexander Kochetkov 
Fixes: 6d9939f651419a63e09110 i2c: omap: split out [XR]DR and [XR]RDY
Tested-by: Felipe Balbi 
Reviewed-by: Felipe Balbi 
Signed-off-by: Wolfram Sang 
Signed-off-by: Greg Kroah-Hartman

i2c: omap: fix NACK and Arbitration Lost irq handling

2014-12-16T17:37:07+00:00

commit 27caca9d2e01c92b26d0690f065aad093fea01c7 upstream.

commit 1d7afc95946487945cc7f5019b41255b72224b70 (i2c: omap: ack IRQ in parts)
changed the interrupt handler to complete transfers without clearing
XRDY (AL case) and ARDY (NACK case) flags. XRDY or ARDY interrupts will be
fired again. As a result, ISR keep processing transfer after it was already
complete (from the driver code point of view).

A didn't see real impacts of the 1d7afc9, but it is really bad idea to
have ISR running on user data after transfer was complete.

It looks, what 1d7afc9 violate TI specs in what how AL and NACK should be
handled (see Note 1, sprugn4r, Figure 17-31 and Figure 17-32).

According to specs (if I understood correctly), in case of NACK and AL driver
must reset NACK, AL, ARDY, RDR, and RRDY (Master Receive Mode), and
NACK, AL, ARDY, and XDR (Master Transmitter Mode).

All that is done down the code under the if condition:
if (stat & (OMAP_I2C_STAT_ARDY | OMAP_I2C_STAT_NACK | OMAP_I2C_STAT_AL)) ...

The patch restore pre 1d7afc9 logic of handling NACK and AL interrupts, so
no interrupts is fired after ISR informs the rest of driver what transfer
complete.

Note: instead of removing break under NACK case, we could just replace 'break'
with 'continue' and allow NACK transfer to finish using ARDY event. I found
that NACK and ARDY bits usually set together. That case confirm TI wiki:
http://processors.wiki.ti.com/index.php/I2C_Tips#Detecting_and_handling_NACK

In order if someone interested in the event traces for NACK and AL cases,
I sent them to mailing list.

Tested on Beagleboard XM C.

Signed-off-by: Alexander Kochetkov 
Fixes: 1d7afc9 i2c: omap: ack IRQ in parts
Acked-by: Felipe Balbi 
Tested-by: Aaro Koskinen 
Signed-off-by: Wolfram Sang 
Signed-off-by: Greg Kroah-Hartman

i2c: at91: don't account as iowait

2014-11-14T18:10:40+00:00

commit 11cfbfb098b22d3e57f1f2be217cad20e2d48463 upstream.

iowait is for blkio [1]. I2C shouldn't use it.

[1] https://lkml.org/lkml/2014/11/3/317

Signed-off-by: Wolfram Sang 
Acked-by: Ludovic Desroches 
Signed-off-by: Greg Kroah-Hartman

i2c: qup: Fix order of runtime pm initialization

2014-10-03T01:20:47+00:00

The runtime pm calls need to be done before populating the children via the
i2c_add_adapter call.  If this is not done, a child can run into issues trying
to do i2c read/writes due to the pm_runtime_sync failing.

Signed-off-by: Andy Gross 
Reviewed-by: Felipe Balbi 
Acked-by: Bjorn Andersson 
Signed-off-by: Wolfram Sang 
Cc: stable@kernel.org

i2c: rk3x: fix 0 length write transfers

2014-10-03T01:18:53+00:00

i2cdetect -q was broken (everything was a false positive, and no transfers were
actually being sent over i2c). The way it works is by sending a 0 length write
request and checking for NACK. This patch fixes the 0 length writes and actually
sends them.

Reported-by: Doug Anderson 
Signed-off-by: Alexandru M Stan 
Tested-by: Doug Anderson 
Tested-by: Max Schwarz 
Signed-off-by: Wolfram Sang 
Cc: stable@kernel.org

i2c: acpi: Fix NULL Pointer dereference

2014-09-25T14:08:15+00:00

If adapter->dev.parent == NULL there is a NULL pointer dereference in
acpi_i2c_install_space_handler and acpi_i2c_remove_space_handler.

This is present since introduction of this code:
366047515c6e "i2c: rework kernel config I2C_ACPI" or even
da3c6647ee08 "I2C/ACPI: Clean up I2C ACPI code and Add CONFIG_I2C_ACPI"

The adapter->dev.parent == NULL case is valid for the i2c_stub,
so loading i2c_stub with ACPI_I2C_OPREGION enabled results in an oops.
This is also valid at least for i2c_tiny_usb and i2c_robotfuzz_osif.

Fix by checking whether it is null before calling ACPI_HANDLE.

Signed-off-by: Peter Huewe 
Acked-by: Mika Westerberg 
Signed-off-by: Wolfram Sang

i2c: move acpi code back into the core

2014-09-25T14:07:15+00:00

Commit 5d98e61d337c ("I2C/ACPI: Add i2c ACPI operation region support")
renamed the i2c-core module. This may cause regressions for
distributions, so put the ACPI code back into the core.

Reported-by: Jean Delvare 
Signed-off-by: Wolfram Sang 
Tested-by: Lan Tianyu 
Tested-by: Mika Westerberg

i2c: rk3x: fix divisor calculation for SCL frequency

2014-09-20T16:35:10+00:00

I2C_CLKDIV register descripted in the previous version of
RK3x chip manual is incorrect. Plus 1 is required.

The correct formula:
- T(SCL_HIGH) = T(PCLK) * (CLKDIVH + 1) * 8
- T(SCL_LOW) = T(PCLK) * (CLKDIVL + 1) * 8
- (SCL Divsor) = 8 * ((CLKDIVL + 1) + (CLKDIVH + 1))
- SCL = PCLK / (CLK Divsor)

It will be updated to the latest version of chip manual.

Signed-off-by: Addy Ke 
Reviewed-by: Doug Anderson 
Signed-off-by: Wolfram Sang 
Cc: stable@kernel.org