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2017-02-20i2c: bcm2835: Avoid possible NULL ptr dereferenceStefan Wahren
Since commit e2474541032d ("bcm2835: Fix hang for writing messages larger than 16 bytes") the interrupt handler is prone to a possible NULL pointer dereference. This could happen if an interrupt fires before curr_msg is set by bcm2835_i2c_xfer_msg() and randomly occurs on the RPi 3. Even this is an unexpected behavior the driver must handle that with an error instead of a crash. Reported-by: Peter Robinson <pbrobinson@gmail.com> Fixes: e2474541032d ("bcm2835: Fix hang for writing messages larger than 16 bytes") Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com> Acked-by: Noralf Trønnes <noralf@tronnes.org> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2016-11-07i2c: bcm2835: Add support for dynamic clockNoralf Trønnes
Support a dynamic clock by reading the frequency and setting the divisor in the transfer function instead of during probe. Signed-off-by: Noralf Trønnes <noralf@tronnes.org> Reviewed-by: Martin Sperl <kernel@martin.sperl.org> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2016-11-07i2c: bcm2835: Support i2c-dev ioctl I2C_TIMEOUTNoralf Trønnes
Use i2c_adapter->timeout for the completion timeout value. The core default is 1 second. Signed-off-by: Noralf Trønnes <noralf@tronnes.org> Reviewed-by: Eric Anholt <eric@anholt.net> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2016-11-07i2c: bcm2835: Add support for Repeated Start ConditionNoralf Trønnes
Documentation/i2c/i2c-protocol states that Combined transactions should separate messages with a Start bit and end the whole transaction with a Stop bit. This patch adds support for issuing only a Start between messages instead of a Stop followed by a Start. This implementation differs from downstream i2c-bcm2708 in 2 respects: - it uses an interrupt to detect that the transfer is active instead of using polling. There is no interrupt for Transfer Active, but by not prefilling the FIFO it's possible to use the TXW interrupt. - when resetting/disabling the controller between transfers it writes CLEAR to the control register instead of just zero. Using just zero gave many errors. This might be the reason why downstream had to disable this feature and make it available with a module parameter. I have run thousands of transfers to a DS1307 (rtc), MMA8451 (accel) and AT24C32 (eeprom) in parallel without problems. Signed-off-by: Noralf Trønnes <noralf@tronnes.org> Acked-by: Eric Anholt <eric@anholt.net> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2016-11-07i2c: bcm2835: Can't support I2C_M_IGNORE_NAKNoralf Trønnes
The controller can't support this flag, so remove it. Documentation/i2c/i2c-protocol states that all of the message is sent: I2C_M_IGNORE_NAK: Normally message is interrupted immediately if there is [NA] from the client. Setting this flag treats any [NA] as [A], and all of message is sent. >From the BCM2835 ARM Peripherals datasheet: The ERR field is set when the slave fails to acknowledge either its address or a data byte written to it. So when the controller doesn't receive an ack, it sets ERR and raises an interrupt. In other words, the whole message is not sent. Signed-off-by: Noralf Trønnes <noralf@tronnes.org> Reviewed-by: Eric Anholt <eric@anholt.net> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2016-11-07i2c: bcm2835: Use dev_dbg logging on transfer errorsNoralf Trønnes
Writing to an AT24C32 generates on average 2x i2c transfer errors per 32-byte page write. Which amounts to a lot for a 4k write. This is due to the fact that the chip doesn't respond during it's internal write cycle when the at24 driver tries and retries the next write. Only a handful drivers use dev_err() on transfer error, so switch to dev_dbg() instead. Signed-off-by: Noralf Trønnes <noralf@tronnes.org> Reviewed-by: Eric Anholt <eric@anholt.net> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2016-11-07i2c: bcm2835: Protect against unexpected TXW/RXR interruptsNoralf Trønnes
If an unexpected TXW or RXR interrupt occurs (msg_buf_remaining == 0), the driver has no way to fill/drain the FIFO to stop the interrupts. In this case the controller has to be disabled and the transfer completed to avoid hang. (CLKT | ERR) and DONE interrupts are completed in their own paths, and the controller is disabled in the transfer function after completion. Unite the code paths and do disabling inside the interrupt routine. Clear interrupt status bits in the united completion path instead of trying to do it on every interrupt which isn't necessary. Only CLKT, ERR and DONE can be cleared that way. Add the status value to the error value in case of TXW/RXR errors to distinguish them from the other S_LEN error. Signed-off-by: Noralf Trønnes <noralf@tronnes.org> Reviewed-by: Eric Anholt <eric@anholt.net> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2016-11-07i2c: bcm2835: Fix hang for writing messages larger than 16 bytesNoralf Trønnes
Writing messages larger than the FIFO size results in a hang, rendering the machine unusable. This is because the RXD status flag is set on the first interrupt which results in bcm2835_drain_rxfifo() stealing bytes from the buffer. The controller continues to trigger interrupts waiting for the missing bytes, but bcm2835_fill_txfifo() has none to give. In this situation wait_for_completion_timeout() apparently is unable to stop the madness. The BCM2835 ARM Peripherals datasheet has this to say about the flags: TXD: is set when the FIFO has space for at least one byte of data. RXD: is set when the FIFO contains at least one byte of data. TXW: is set during a write transfer and the FIFO is less than full. RXR: is set during a read transfer and the FIFO is or more full. Implementing the logic from the downstream i2c-bcm2708 driver solved the hang problem. Signed-off-by: Noralf Trønnes <noralf@tronnes.org> Reviewed-by: Eric Anholt <eric@anholt.net> Reviewed-by: Martin Sperl <kernel@martin.sperl.org> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2016-07-22i2c: bcm2835: Don't complain on -EPROBE_DEFER from getting our clockEric Anholt
Fixes dmesg spam when we just need to wait a moment for the clock driver to probe. Signed-off-by: Eric Anholt <eric@anholt.net> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2015-11-30i2c: bcm2835: add I2C_AQ_NO_CLK_STRETCHNicola Corna
As reported in the links given below. the BCM2835 has a hardware bug in its i2c module which prevents a correct clock stretching. This patch adds the I2C_AQ_NO_CLK_STRETCH quirk flag to i2c-bcm2835. Signed-off-by: Nicola Corna <nicola@corna.info> [wsa: put the links into the code as comments] Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2015-06-23i2c: busses: i2c-bcm2835: limits cdiv to allowed valuesSilvan Wicki
Checks if the cdiv value is in between min (0x2) and max (0xFFFE) supported values by the bcm2835. If not, it returns -ENODEV. See page 33/34 of BCM2835-ARM-Peripherals.pdf for the DIV register. https://www.raspberrypi.org/wp-content/uploads/2012/02/BCM2835-ARM-Peripherals.pdf Signed-off-by: Silvan Wicki <linux_wi@tinag.ch> [wsa: resolved a merge conflict] Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2015-06-17i2c: bcm2835: clear reserved bits in S-RegisterSilvan Wicki
The datasheet mentions on page 31 that the bits 10-31 must be read as don't care and written as 0. https://www.raspberrypi.org/wp-content/uploads/2012/02/BCM2835-ARM-Peripherals.pdf We cannot guarantee that we read bits 10-31 as always 0 (because the datasheet says read as don't care). We clear the bits with a bitmask to prevent writing back unknown data at the reserved bits. Signed-off-by: Silvan Wicki <linux_wi@tinag.ch> Acked-by: Stephen Warren <swarren@wwwdotorg.org> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2015-03-15i2c: i2c-bcm2835: match return type of wait_for_completion_timeoutNicholas Mc Guire
return type of wait_for_completion_timeout is unsigned long not int. as time_left is used for wait_for_completion_timeout exclusively here its type is simply changed to unsigned long. Signed-off-by: Nicholas Mc Guire <hofrat@osadl.org> Acked-by: Lee Jones <lee.jones@linaro.org> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2014-10-20i2c: busses: drop owner assignment from platform_driversWolfram Sang
A platform_driver does not need to set an owner, it will be populated by the driver core. Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2014-07-16i2c: i2c-bcm2835: Drop class based scanning to improve bootup timeWolfram Sang
This driver has been flagged to drop class based instantiation. The removal improves boot-up time and is unneeded for embedded controllers. Users have been warned to switch for some time now, so we can actually do the removal. Keep the DEPRECATED flag, so the core can inform users that the behaviour finally changed now. After another transition period, this flag can go, too. Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2014-06-02i2c: remove unnecessary OOM messagesJingoo Han
The site-specific OOM messages are unnecessary, because they duplicate the MM subsystem generic OOM message. For example, k.alloc and v.alloc failures use dump_stack(). Signed-off-by: Jingoo Han <jg1.han@samsung.com> Acked-by: Guenter Roeck <linux@roeck-us.net> Reviewed-by: Jean Delvare <jdelvare@suse.de> Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Acked-by: Felipe Balbi <balbi@ti.com> Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Acked-by: Linus Walleij <linus.walleij@linaro.org> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2014-03-28i2c: i2c-bcm2835: deprecate class based instantiationWolfram Sang
Warn users that class based instantiation is going away soon in favour of more robust probing and faster bootup times. Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2014-03-09i2c: bcm2835: Use devm_ioremap_resource()Jingoo Han
Use devm_ioremap_resource() in order to make the code simpler, and remove redundant return value check of platform_get_resource() because the value is checked by devm_ioremap_resource(). Signed-off-by: Jingoo Han <jg1.han@samsung.com> Acked-by: Stephen Warren <swarren@wwwdotorg.org> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2013-11-28i2c: bcm2835: Linking platform nodes to adapter nodesFlorian Meier
In order to find I2C devices in the device tree, the platform nodes have to be known by the I2C core. This requires setting the dev.of_node parameter of the adapter. Signed-off-by: Florian Meier <florian.meier@koalo.de> Tested-by: Stephen Warren <swarren@wwwdotorg.org> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2013-11-15tree-wide: use reinit_completion instead of INIT_COMPLETIONWolfram Sang
Use this new function to make code more comprehensible, since we are reinitialzing the completion, not initializing. [akpm@linux-foundation.org: linux-next resyncs] Signed-off-by: Wolfram Sang <wsa@the-dreams.de> Acked-by: Linus Walleij <linus.walleij@linaro.org> (personally at LCE13) Cc: Ingo Molnar <mingo@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-02-12i2c: add bcm2835 driverStephen Warren
This implements a very basic I2C host driver for the BCM2835 SoC. Missing features so far are: * 10-bit addressing. * DMA. Reviewed-by: Grant Likely <grant.likely@secretlab.ca> Signed-off-by: Stephen Warren <swarren@wwwdotorg.org> Signed-off-by: Wolfram Sang <wolfram@the-dreams.de>