linux-toradex.git/drivers/i2c, branch v3.18.13 Linux kernel for Apalis and Colibri modules Revert "i2c: core: Dispose OF IRQ mapping at client removal time" 2015-03-28T13:53:02+00:00 Jakub Kicinski kubakici@wp.pl 2015-03-11T17:35:36+00:00 9297c326266dd08af2c7be30cbab32787eef9b9f [ Upstream commit a49445727014216703a3c28ccee4cef36d41571e ] This reverts commit e4df3a0b6228 ("i2c: core: Dispose OF IRQ mapping at client removal time") Calling irq_dispose_mapping() will destroy the mapping and disassociate the IRQ from the IRQ chip to which it belongs. Keeping it is OK, because existent mappings are reused properly. Also, this commit breaks drivers using devm* for IRQ management on OF-based systems because devm* cleanup happens in device code, after bus's remove() method returns. Signed-off-by: Jakub Kicinski <kubakici@wp.pl> Reported-by: Sébastien Szymanski <sebastien.szymanski@armadeus.com> Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com> [wsa: updated the commit message with findings fromt the other bug report] Signed-off-by: Wolfram Sang <wsa@the-dreams.de> Cc: stable@kernel.org Fixes: e4df3a0b6228 Signed-off-by: Sasha Levin <sasha.levin@oracle.com> 
[ Upstream commit a49445727014216703a3c28ccee4cef36d41571e ]

This reverts commit e4df3a0b6228
("i2c: core: Dispose OF IRQ mapping at client removal time")

Calling irq_dispose_mapping() will destroy the mapping and disassociate
the IRQ from the IRQ chip to which it belongs. Keeping it is OK, because
existent mappings are reused properly.

Also, this commit breaks drivers using devm* for IRQ management on
OF-based systems because devm* cleanup happens in device code, after
bus's remove() method returns.

Signed-off-by: Jakub Kicinski <kubakici@wp.pl>
Reported-by: Sébastien Szymanski <sebastien.szymanski@armadeus.com>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
[wsa: updated the commit message with findings fromt the other bug report]
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Cc: stable@kernel.org
Fixes: e4df3a0b6228

Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
i2c: s3c2410: fix ABBA deadlock by keeping clock prepared 2015-02-06T06:36:04+00:00 Paul Osmialowski p.osmialowsk@samsung.com 2015-01-19T16:03:33+00:00 5e1b35cfd680fe9d67bb2754393ff8e1e8ddf713 commit 34e81ad5f0b60007c95995eb7803da7e00c6c611 upstream. This patch solves deadlock between clock prepare mutex and regmap mutex reported by Tomasz Figa in [1] by implementing solution from [2]: "always leave the clock of the i2c controller in a prepared state". [1] https://lkml.org/lkml/2014/7/2/171 [2] https://lkml.org/lkml/2014/7/2/207 On each i2c transfer handled by s3c24xx_i2c_xfer(), clk_prepare_enable() was called, which calls clk_prepare() then clk_enable(). clk_prepare() takes prepare_lock mutex before proceeding. Note that i2c transfer functions are invoked from many places in kernel, typically with some other additional lock held. It may happen that function on CPU1 (e.g. regmap_update_bits()) has taken a mutex (i.e. regmap lock mutex) then it attempts i2c communication in order to proceed (so it needs to obtain clock related prepare_lock mutex during transfer preparation stage due to clk_prepare() call). At the same time other task on CPU0 wants to operate on clock (e.g. to (un)prepare clock for some other reason) so it has taken prepare_lock mutex. CPU0: CPU1: clk_disable_unused() regulator_disable() clk_prepare_lock() map->lock(map->lock_arg) regmap_read() s3c24xx_i2c_xfer() map->lock(map->lock_arg) clk_prepare_lock() Implemented solution from [2] leaves i2c clock prepared. Preparation is done in s3c24xx_i2c_probe() function. Without this patch, it is immediately unprepared by clk_disable_unprepare() call. I've replaced this call with clk_disable() and I've added clk_unprepare() call in s3c24xx_i2c_remove(). The s3c24xx_i2c_xfer() function now uses clk_enable() instead of clk_prepare_enable() (and clk_disable() instead of clk_unprepare_disable()). Signed-off-by: Paul Osmialowski <p.osmialowsk@samsung.com> Reviewed-by: Krzysztof Kozlowski <k.kozlowski@samsung.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 34e81ad5f0b60007c95995eb7803da7e00c6c611 upstream.

This patch solves deadlock between clock prepare mutex and regmap mutex reported
by Tomasz Figa in [1] by implementing solution from [2]: "always leave the clock
of the i2c controller in a prepared state".

[1] https://lkml.org/lkml/2014/7/2/171
[2] https://lkml.org/lkml/2014/7/2/207

On each i2c transfer handled by s3c24xx_i2c_xfer(), clk_prepare_enable() was
called, which calls clk_prepare() then clk_enable(). clk_prepare() takes
prepare_lock mutex before proceeding. Note that i2c transfer functions are
invoked from many places in kernel, typically with some other additional lock
held.

It may happen that function on CPU1 (e.g. regmap_update_bits()) has taken a
mutex (i.e. regmap lock mutex) then it attempts i2c communication in order to
proceed (so it needs to obtain clock related prepare_lock mutex during transfer
preparation stage due to clk_prepare() call). At the same time other task on
CPU0 wants to operate on clock (e.g. to (un)prepare clock for some other reason)
so it has taken prepare_lock mutex.

CPU0:                        CPU1:
clk_disable_unused()         regulator_disable()
  clk_prepare_lock()           map->lock(map->lock_arg)
  regmap_read()                s3c24xx_i2c_xfer()
    map->lock(map->lock_arg)     clk_prepare_lock()

Implemented solution from [2] leaves i2c clock prepared. Preparation is done in
s3c24xx_i2c_probe() function. Without this patch, it is immediately unprepared
by clk_disable_unprepare() call. I've replaced this call with clk_disable() and
I've added clk_unprepare() call in s3c24xx_i2c_remove().

The s3c24xx_i2c_xfer() function now uses clk_enable() instead of
clk_prepare_enable() (and clk_disable() instead of clk_unprepare_disable()).

Signed-off-by: Paul Osmialowski <p.osmialowsk@samsung.com>
Reviewed-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
i2c: cadence: Set the hardware time-out register to maximum value 2014-12-04T18:25:41+00:00 Vishnu Motghare vishnum@xilinx.com 2014-12-03T12:35:25+00:00 681d15a0f527af7ab3a783e1037de86fbcb136ac 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 <vishnum@xilinx.com> Signed-off-by: Harini Katakam <harinik@xilinx.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de> Cc: stable@kernel.org 
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 <vishnum@xilinx.com>
Signed-off-by: Harini Katakam <harinik@xilinx.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Cc: stable@kernel.org
i2c: davinci: generate STP always when NACK is received 2014-12-04T18:25:31+00:00 Grygorii Strashko grygorii.strashko@ti.com 2014-12-01T15:34:04+00:00 9ea359f7314132cbcb5a502d2d8ef095be1f45e4 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 <u.kleine-koenig@pengutronix.de> Reported-by: Hein Tibosch <hein_tibosch@yahoo.es> Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de> Cc: stable@kernel.org 
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 <u.kleine-koenig@pengutronix.de>
Reported-by: Hein Tibosch <hein_tibosch@yahoo.es>
Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Cc: stable@kernel.org
i2c: omap: fix i207 errata handling 2014-11-22T21:07:40+00:00 Alexander Kochetkov al.kochet@gmail.com 2014-11-21T00:16:51+00:00 ccfc866356674cb3a61829d239c685af6e85f197 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 <al.kochet@gmail.com> Fixes: 6d9939f651419a63e09110 i2c: omap: split out [XR]DR and [XR]RDY Tested-by: Felipe Balbi <balbi@ti.com> Reviewed-by: Felipe Balbi <balbi@ti.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de> 
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 <al.kochet@gmail.com>
Fixes: 6d9939f651419a63e09110 i2c: omap: split out [XR]DR and [XR]RDY
Tested-by: Felipe Balbi <balbi@ti.com>
Reviewed-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
i2c: designware: prevent early stop on TX FIFO empty 2014-11-21T07:06:32+00:00 Andrew Jackson Andrew.Jackson@arm.com 2014-11-07T12:10:44+00:00 d39f77b06a712fcba6185a20bb209e357923d980 If the Designware core is configured with IC_EMPTYFIFO_HOLD_MASTER_EN set to zero, allowing the TX FIFO to become empty causes a STOP condition to be generated on the I2C bus. If the transmit FIFO threshold is set too high, an erroneous STOP condition can be generated on long transfers - particularly where the interrupt latency is extended. Signed-off-by: Andrew Jackson <Andrew.Jackson@arm.com> Signed-off-by: Liviu Dudau <Liviu.Dudau@arm.com> Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de> 
If the Designware core is configured with IC_EMPTYFIFO_HOLD_MASTER_EN
set to zero, allowing the TX FIFO to become empty causes a STOP
condition to be generated on the I2C bus. If the transmit FIFO
threshold is set too high, an erroneous STOP condition can be
generated on long transfers - particularly where the interrupt
latency is extended.

Signed-off-by: Andrew Jackson <Andrew.Jackson@arm.com>
Signed-off-by: Liviu Dudau <Liviu.Dudau@arm.com>
Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
i2c: omap: fix NACK and Arbitration Lost irq handling 2014-11-21T07:06:31+00:00 Alexander Kochetkov al.kochet@gmail.com 2014-11-18T17:00:58+00:00 27caca9d2e01c92b26d0690f065aad093fea01c7 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 <al.kochet@gmail.com> Fixes: 1d7afc9 i2c: omap: ack IRQ in parts Cc: <stable@vger.kernel.org> # v3.7+ Acked-by: Felipe Balbi <balbi@ti.com> Tested-by: Aaro Koskinen <aaro.koskinen@iki.fi> Signed-off-by: Wolfram Sang <wsa@the-dreams.de> 
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 <al.kochet@gmail.com>
Fixes: 1d7afc9 i2c: omap: ack IRQ in parts
Cc: <stable@vger.kernel.org> # v3.7+
Acked-by: Felipe Balbi <balbi@ti.com>
Tested-by: Aaro Koskinen <aaro.koskinen@iki.fi>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
i2c: core: Dispose OF IRQ mapping at client removal time 2014-11-07T18:03:18+00:00 Laurent Pinchart laurent.pinchart+renesas@ideasonboard.com 2014-10-30T13:59:37+00:00 e4df3a0b62285130ac0a35cf07678c154ffb649d Clients instantiated from OF get an IRQ mapping created at device registration time. Dispose the mapping when the client is removed. Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de> Cc: stable@kernel.org 
Clients instantiated from OF get an IRQ mapping created at device
registration time. Dispose the mapping when the client is removed.

Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Cc: stable@kernel.org
i2c: at91: don't account as iowait 2014-11-07T17:56:31+00:00 Wolfram Sang wsa@the-dreams.de 2014-11-03T20:16:16+00:00 11cfbfb098b22d3e57f1f2be217cad20e2d48463 iowait is for blkio [1]. I2C shouldn't use it. [1] https://lkml.org/lkml/2014/11/3/317 Signed-off-by: Wolfram Sang <wsa@the-dreams.de> Acked-by: Ludovic Desroches <ludovic.desroches@atmel.com> Cc: stable@kernel.org 
iowait is for blkio [1]. I2C shouldn't use it.

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

Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Acked-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Cc: stable@kernel.org
i2c: remove FSF address 2014-11-07T17:35:33+00:00 Wolfram Sang wsa+renesas@sang-engineering.com 2014-11-04T22:46:27+00:00 ca1f8da9ac5ce6e63d8f6933f83fabc1f3f961f4 We have a central copy of the GPL for that. Some addresses were already outdated. Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com> 
We have a central copy of the GPL for that. Some addresses were already
outdated.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>