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alistair23-linux/drivers/i2c/busses
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Javier Martinez Canillas 10ff4c5239 i2c: exynos5: Fix possible ABBA deadlock by keeping I2C clock prepared 
The exynos5 I2C controller driver always prepares and enables a clock
before using it and then disables unprepares it when the clock is not
used anymore.

But this can cause a possible ABBA deadlock in some scenarios since a
driver that uses regmap to access its I2C registers, will first grab
the regmap lock and then the I2C xfer function will grab the prepare
lock when preparing the I2C clock. But since the clock driver also
uses regmap for I2C accesses, preparing a clock will first grab the
prepare lock and then the regmap lock when using the regmap API.

An example of this happens on the Exynos5422 Odroid XU4 board where a
s2mps11 PMIC is used and both the s2mps11 regulators and clk drivers
share the same I2C regmap.

The possible deadlock is reported by the kernel lockdep:

  Possible unsafe locking scenario:

        CPU0                    CPU1
        ----                    ----
   lock(sec_core:428:(regmap)->lock);
                                lock(prepare_lock);
                                lock(sec_core:428:(regmap)->lock);
   lock(prepare_lock);

  *** DEADLOCK ***

Fix it by leaving the code prepared on probe and use {en,dis}able in
the I2C transfer function.

This patch is similar to commit 34e81ad5f0 ("i2c: s3c2410: fix ABBA
deadlock by keeping clock prepared") that fixes the same bug in other
driver for an I2C controller found in Samsung SoCs.

Reported-by: Anand Moon <linux.amoon@gmail.com>
Signed-off-by: Javier Martinez Canillas <javier@osg.samsung.com>
Reviewed-by: Anand Moon <linux.amoon@gmail.com>
Reviewed-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Cc: stable@kernel.org
2016-04-22 15:31:54 +02:00
..
i2c-acorn.c i2c: acorn: is tristate and should use module.h 2014-01-24 18:21:11 +01:00
i2c-ali15x3.c i2c: remove FSF address 2014-11-07 18:35:33 +01:00
i2c-ali1535.c i2c: remove FSF address 2014-11-07 18:35:33 +01:00
i2c-ali1563.c i2c: ali1563: fix checkpatch.pl issues 2014-05-22 10:09:21 +02:00
i2c-amd756-s4882.c i2c: remove FSF address 2014-11-07 18:35:33 +01:00
i2c-amd756.c i2c: remove FSF address 2014-11-07 18:35:33 +01:00
i2c-amd8111.c i2c: remove DEFINE_PCI_DEVICE_TABLE macro 2014-03-13 09:44:59 +01:00
i2c-at91.c i2c: at91: add support for the HOLD field 2015-12-03 21:42:37 +01:00
i2c-au1550.c i2c: au1550: Convert to devm_kzalloc and devm_ioremap_resource 2015-10-23 23:31:11 +02:00
i2c-axxia.c i2c: axxia: Add bus recovery functionality 2015-06-03 00:40:16 +09:00
i2c-bcm-iproc.c i2c: iproc: Support larger TX transfer 2016-02-12 22:43:08 +01:00
i2c-bcm-kona.c i2c: busses: drop owner assignment from platform_drivers 2014-10-20 16:20:37 +02:00
i2c-bcm2835.c i2c: bcm2835: add I2C_AQ_NO_CLK_STRETCH 2015-11-30 18:37:26 +01:00
i2c-bfin-twi.c i2c: Fix typo in i2c-bfin-twi.c 2015-07-31 13:32:31 +02:00
i2c-brcmstb.c i2c: brcmstb: allocate correct amount of memory for regmap 2016-03-01 19:16:45 +01:00
i2c-cadence.c i2c: cadence: Fix the kernel-doc warnings 2016-03-12 15:59:22 +01:00
i2c-cbus-gpio.c i2c: busses: drop owner assignment from platform_drivers 2014-10-20 16:20:37 +02:00
i2c-cpm.c i2c: cpm: Fix build break due to incompatible pointer types 2016-04-22 15:25:53 +02:00
i2c-cros-ec-tunnel.c mfd: cros_ec: Use a zero-length array for command data 2015-06-15 13:18:19 +01:00
i2c-davinci.c i2c: davinci: Increase module clock frequency 2015-11-30 15:55:07 +01:00
i2c-designware-baytrail.c i2c: designware-platform: Drop duplicate module information 2016-02-12 20:40:13 +01:00
i2c-designware-core.c i2c: designware: Prevent runtime suspend during adapter registration 2016-02-12 20:40:14 +01:00
i2c-designware-core.h i2c: designware: remove redundant lock 2016-02-12 20:40:12 +01:00
i2c-designware-pcidrv.c i2c: designware: use to_pci_dev() 2016-01-03 19:54:00 +01:00
i2c-designware-platdrv.c i2c: designware: Add device HID for future AMD I2C controller 2016-03-10 21:34:47 +01:00
i2c-digicolor.c i2c: digicolor: remove duplicate include 2015-04-23 19:35:32 +02:00
i2c-diolan-u2c.c i2c: remove unnecessary OOM messages 2014-06-02 19:24:33 +02:00
i2c-dln2.c i2c: dln2: set the device tree node of the adapter 2015-03-27 16:56:21 +01:00
i2c-efm32.c i2c: busses: drop owner assignment from platform_drivers 2014-10-20 16:20:37 +02:00
i2c-eg20t.c i2c: eg20t: set i2c_adapter->dev.of_node 2015-12-03 22:11:46 +01:00
i2c-elektor.c i2c: remove FSF address 2014-11-07 18:35:33 +01:00
i2c-emev2.c i2c: emev2: add slave support 2015-12-05 19:55:36 +01:00
i2c-exynos5.c i2c: exynos5: Fix possible ABBA deadlock by keeping I2C clock prepared 2016-04-22 15:31:54 +02:00
i2c-gpio.c i2c: busses: drop owner assignment from platform_drivers 2014-10-20 16:20:37 +02:00
i2c-highlander.c i2c: busses: drop owner assignment from platform_drivers 2014-10-20 16:20:37 +02:00
i2c-hix5hd2.c i2c: hix5hd2: Fix modalias to make module auto-loading work 2015-05-12 18:09:33 +02:00
i2c-hydra.c i2c: remove FSF address 2014-11-07 18:35:33 +01:00
i2c-i801.c Merge branch 'i2c/for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux 2016-03-22 12:47:40 -07:00
i2c-ibm_iic.c i2c: ibm_iic: rename i2c_timings struct due to clash with generic version 2016-01-05 02:06:10 +01:00
i2c-ibm_iic.h i2c-ibm_iic: Whitespace cleanup 2008-01-27 18:14:45 +01:00
i2c-img-scb.c i2c: img-scb: support repeated starts on IP v3.3 2016-01-02 22:05:21 +01:00
i2c-imx.c i2c: imx: remove extra spaces. 2016-03-03 22:31:13 +01:00
i2c-iop3xx.c i2c: busses: drop owner assignment from platform_drivers 2014-10-20 16:20:37 +02:00
i2c-iop3xx.h i2c: remove FSF address 2014-11-07 18:35:33 +01:00
i2c-isch.c Driver core patches for 3.19-rc1 2014-12-14 16:10:09 -08:00
i2c-ismt.c i2c: ismt: Add Intel DNV PCI ID 2016-04-12 23:44:16 +02:00
i2c-jz4780.c i2c: jz4780: really prevent potential division by zero 2016-04-09 08:36:44 +02:00
i2c-kempld.c i2c: busses: drop owner assignment from platform_drivers 2014-10-20 16:20:37 +02:00
i2c-lpc2k.c i2c: lpc2k: add driver 2015-08-24 14:05:18 +02:00
i2c-meson.c i2c: meson: Fix module autoload for OF platform driver 2015-10-20 18:14:36 +02:00
i2c-mpc.c i2c: mpc: Fix ISR return value 2015-03-27 16:53:41 +01:00
i2c-mt65xx.c i2c: mt65xx: add 4GB DMA mode support in i2c driver 2016-02-12 20:40:15 +01:00
i2c-mv64xxx.c i2c: mv64xxx: The n clockdiv factor is 0 based on sunxi SoCs 2015-11-30 15:54:22 +01:00
i2c-mxs.c i2c: constify platform_device_id 2015-05-12 18:27:48 +02:00
i2c-nforce2-s4985.c i2c: remove FSF address 2014-11-07 18:35:33 +01:00
i2c-nforce2.c i2c: remove FSF address 2014-11-07 18:35:33 +01:00
i2c-nomadik.c i2c: nomadik: match status to return type of read_i2c 2015-03-15 10:51:13 +01:00
i2c-ocores.c i2c: ocores: support big-endian register layout 2015-10-20 17:47:45 +02:00
i2c-octeon.c i2c: octeon: Support I2C_M_RECV_LEN 2016-03-18 15:50:42 +01:00
i2c-omap.c i2c: omap: Fix PM regression with deferred probe for pm_runtime_reinit 2016-02-12 19:42:31 +01:00
i2c-opal.c i2c: opal: Update quirk flags to do write-then-anything 2015-03-14 12:08:21 +01:00
i2c-parport-light.c Driver core patches for 3.19-rc1 2014-12-14 16:10:09 -08:00
i2c-parport.c i2c: parport: start using pr_fmt 2015-08-10 08:37:28 +02:00
i2c-parport.h i2c: parport: Add VCT-jig adapter 2015-08-10 08:37:34 +02:00
i2c-pasemi.c i2c: remove FSF address 2014-11-07 18:35:33 +01:00
i2c-pca-isa.c i2c: remove FSF address 2014-11-07 18:35:33 +01:00
i2c-pca-platform.c i2c: pca-platform: fix broken email address 2015-04-23 19:35:30 +02:00
i2c-piix4.c i2c: piix4: Pre-shift the port number 2016-02-24 15:59:06 +01:00
i2c-pmcmsp.c i2c: pmcmsp: make use of the new infrastructure for quirks 2015-03-13 15:10:58 +01:00
i2c-pnx.c Merge branch 'i2c/for-4.4' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux 2015-11-10 11:58:25 -08:00
i2c-powermac.c i2c: powermac: make use of the new infrastructure for quirks 2015-03-13 15:10:57 +01:00
i2c-puv3.c i2c: busses: drop owner assignment from platform_drivers 2014-10-20 16:20:37 +02:00
i2c-pxa-pci.c i2c: remove DEFINE_PCI_DEVICE_TABLE macro 2014-03-13 09:44:59 +01:00
i2c-pxa.c i2c: pxa: Add support for pxa910/988 & new configuration features 2015-10-25 09:36:43 +01:00
i2c-qup.c i2c: qup: Fix fifo handling after adding V2 support 2016-03-03 22:25:22 +01:00
i2c-rcar.c i2c: rcar: don't open code of_device_get_match_data() 2016-03-03 22:25:23 +01:00
i2c-riic.c i2c: busses: drop owner assignment from platform_drivers 2014-10-20 16:20:37 +02:00
i2c-rk3x.c i2c: rk3x: add support for rk3228 2016-04-12 23:34:44 +02:00
i2c-robotfuzz-osif.c i2c: Add bus driver for for OSIF USB i2c device. 2014-01-13 13:56:56 +01:00
i2c-s3c2410.c i2c: s3c2410: remove superfluous runtime PM calls 2016-01-10 09:27:53 +01:00
i2c-scmi.c i2c: delete non-required instances of include <linux/init.h> 2014-01-24 18:24:31 +01:00
i2c-sh7760.c i2c: busses: drop owner assignment from platform_drivers 2014-10-20 16:20:37 +02:00
i2c-sh_mobile.c i2c: sh_mobile: add support for r8a7795 (R-Car H3) 2015-10-20 18:10:20 +02:00
i2c-sibyte.c i2c: remove FSF address 2014-11-07 18:35:33 +01:00
i2c-simtec.c Driver core patches for 3.19-rc1 2014-12-14 16:10:09 -08:00
i2c-sirf.c i2c: sirf: tune the divider to make i2c bus freq more accurate 2015-10-23 22:48:45 +02:00
i2c-sis96x.c i2c: remove FSF address 2014-11-07 18:35:33 +01:00
i2c-sis630.c i2c: remove FSF address 2014-11-07 18:35:33 +01:00
i2c-sis5595.c i2c: remove FSF address 2014-11-07 18:35:33 +01:00
i2c-st.c Merge branch 'i2c/for-4.5' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux 2016-01-14 11:25:37 -08:00
i2c-stu300.c i2c: stu300: Fix module autoload for OF platform driver 2015-10-20 18:15:39 +02:00
i2c-sun6i-p2wi.c i2c: busses: drop owner assignment from platform_drivers 2014-10-20 16:20:37 +02:00
i2c-taos-evm.c i2c: taos-evm: replace simple_strtoul by kstrtou8 2015-11-30 18:37:22 +01:00
i2c-tegra.c i2c: tegra: don't open code of_device_get_match_data() 2016-02-24 11:24:29 +01:00
i2c-tiny-usb.c i2c: i2c-tiny-usb: Remove RobotFuzz USB vendor:product ID 2014-01-13 13:56:52 +01:00
i2c-uniphier-f.c i2c: uniphier: fix typos in error messages 2016-02-12 20:23:37 +01:00
i2c-uniphier.c i2c: uniphier: fix typos in error messages 2016-02-12 20:23:37 +01:00
i2c-versatile.c i2c: busses: drop owner assignment from platform_drivers 2014-10-20 16:20:37 +02:00
i2c-via.c i2c: remove FSF address 2014-11-07 18:35:33 +01:00
i2c-viapro.c i2c: remove FSF address 2014-11-07 18:35:33 +01:00
i2c-viperboard.c i2c: viperboard: clean up inconsistent indenting 2015-08-10 08:37:38 +02:00
i2c-wmt.c i2c: wmt: match return type of wait_for_completion_timeout 2015-03-15 10:29:53 +01:00
i2c-xgene-slimpro.c i2c: xgene-slimpro: dma_mapping_error() doesn't return an error code 2015-08-24 14:23:31 +02:00
i2c-xiic.c i2c: xiic: Implement power management 2016-03-03 22:25:17 +01:00
i2c-xlp9xx.c i2c: xlp9xx: Driver for Netlogic XLP9XX/5XX I2C controller 2015-04-10 18:59:49 +02:00
i2c-xlr.c i2c: xlr: add interrupt support for Sigma Designs chips 2015-12-16 11:42:58 +01:00
Kconfig i2c: xlp9xx: add support for Broadcom Vulcan 2016-04-12 23:40:11 +02:00
Makefile i2c: uniphier_f: add UniPhier FIFO-builtin I2C driver 2015-10-23 21:55:46 +02:00
scx200_acb.c Driver core patches for 3.19-rc1 2014-12-14 16:10:09 -08:00