linux-stable.git/drivers/iio, branch v4.12.2 Linux kernel stable tree iio: buffer-dmaengine: Add missing header buffer_impl.h 2017-06-13T19:56:05+00:00 Phil Reid preid@electromag.com.au 2017-06-13T05:12:35+00:00 7981dc07fe317e3506d706e5ef91b94da02656f4 Add buffer_impl.h as buffer.h was split into interface for using and for internals. Without this industrialio-buffer-dmaengine.c fails to compile. Fixes: commit 33dd94cb972175249258329c4aaffddcc82c2005 ("iio:buffer.h - split into buffer.h and buffer_impl.h") Signed-off-by: Phil Reid <preid@electromag.com.au> Signed-off-by: Jonathan Cameron <jic23@kernel.org> 
Add buffer_impl.h as buffer.h was split into interface for using and
for internals. Without this industrialio-buffer-dmaengine.c fails
to compile.

Fixes:
commit 33dd94cb972175249258329c4aaffddcc82c2005 ("iio:buffer.h - split
into buffer.h and buffer_impl.h")

Signed-off-by: Phil Reid <preid@electromag.com.au>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
iio: buffer-dma: Add missing header buffer_impl.h 2017-06-13T19:55:59+00:00 Phil Reid preid@electromag.com.au 2017-06-13T02:31:36+00:00 838519b89fa7e162f7190c70d888a65ee7889e12 Add buffer_impl.h as buffer.h was split into interface for using and for internals. Without this industrialio-buffer-dma.c fails to compile. Fixes: commit 33dd94cb972175249258329c4aaffddcc82c2005 ("iio:buffer.h - split into buffer.h and buffer_impl.h") Signed-off-by: Phil Reid <preid@electromag.com.au> Signed-off-by: Jonathan Cameron <jic23@kernel.org> 
Add buffer_impl.h as buffer.h was split into interface for using and
for internals. Without this industrialio-buffer-dma.c fails
to compile.

Fixes:
commit 33dd94cb972175249258329c4aaffddcc82c2005 ("iio:buffer.h - split
into buffer.h and buffer_impl.h")

Signed-off-by: Phil Reid <preid@electromag.com.au>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
iio: adc: meson-saradc: fix potential crash in meson_sar_adc_clear_fifo 2017-06-11T14:00:13+00:00 Martin Blumenstingl martin.blumenstingl@googlemail.com 2017-06-04T13:28:23+00:00 103a07d4278203d6299798cd74cdc4d209801cac meson_sar_adc_clear_fifo passes a 0 as value-pointer to regmap_read(). In case of the meson-saradc driver this ends up in regmap_mmio_read(), where the value-pointer is de-referenced unconditionally to assign the value which was read. Fix this by passing an actual pointer, even though all we want to do is to discard the value. As a side-effect this fixes a sparse warning ("Using plain integer as NULL pointer") as reported by Paolo Cretaro. Fixes: 3adbf3427330 ("iio: adc: add a driver for the SAR ADC found in Amlogic Meson SoCs") Reported-by: Paolo Cretaro <paolocretaro@gmail.com> Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com> Cc: <Stable@vger.kernel.org> Signed-off-by: Jonathan Cameron <jic23@kernel.org> 
meson_sar_adc_clear_fifo passes a 0 as value-pointer to regmap_read().
In case of the meson-saradc driver this ends up in regmap_mmio_read(),
where the value-pointer is de-referenced unconditionally to assign the
value which was read.
Fix this by passing an actual pointer, even though all we want to do is
to discard the value.

As a side-effect this fixes a sparse warning ("Using plain integer as
NULL pointer") as reported by Paolo Cretaro.

Fixes: 3adbf3427330 ("iio: adc: add a driver for the SAR ADC found in Amlogic Meson SoCs")
Reported-by: Paolo Cretaro <paolocretaro@gmail.com>
Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
iio: adc: mxs-lradc: Fix return value check in mxs_lradc_adc_probe() 2017-06-03T09:52:31+00:00 Wei Yongjun weiyongjun1@huawei.com 2017-05-16T15:26:12+00:00 1454e15bc28ba94aa5d6b31a83a42d5c03af2a6d In case of error, the function devm_ioremap() returns NULL pointer not ERR_PTR(). The IS_ERR() test in the return value check should be replaced with NULL test. Also add NULL test for iores. Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com> Signed-off-by: Jonathan Cameron <jic23@kernel.org> 
In case of error, the function devm_ioremap() returns NULL pointer
not ERR_PTR(). The IS_ERR() test in the return value check should
be replaced with NULL test. Also add NULL test for iores.

Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
iio: imu: inv_mpu6050: add accel lpf setting for chip >= MPU6500 2017-06-03T08:40:40+00:00 Jean-Baptiste Maneyrol JManeyrol@invensense.com 2017-05-29T09:59:40+00:00 948588e25b8af5e66962ed3f53e1cae1656fa5af Starting from MPU6500, accelerometer dlpf is set in a separate register named ACCEL_CONFIG_2. Add this new register in the map and set it for the corresponding chips. Signed-off-by: Jean-Baptiste Maneyrol <jmaneyrol@invensense.com> Cc: stable@vger.kernel.org Signed-off-by: Jonathan Cameron <jic23@kernel.org> 
Starting from MPU6500, accelerometer dlpf is set in a separate
register named ACCEL_CONFIG_2.
Add this new register in the map and set it for the corresponding
chips.

Signed-off-by: Jean-Baptiste Maneyrol <jmaneyrol@invensense.com>
Cc: stable@vger.kernel.org
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Merge tag 'iio-fixes-for-4.12a' of git://git.kernel.org/pub/scm/linux/kernel/git/jic23/iio into staging-linus 2017-05-22T19:53:09+00:00 Greg Kroah-Hartman gregkh@linuxfoundation.org 2017-05-22T19:53:09+00:00 5a4733df7ef255446a213ee84efa5713a9765688 Jonathan writes: First set of IIO fixes in the 4.12 cycle. Matt finally set up the lightning storm he needed to test the as3935. * core - Fix a null pointer deference in iio_trigger_write_current when changing from a non existent trigger to another non existent trigger. * a3935 - Recalibrate the RCO after resume. - Fix interrupt mask so that we actually get some interrupts. - Use iio_trigger_poll_chained as we aren't in interrupt context. * am335x - Fix wrong allocation size provided for private data to iio_device_alloc. * bcm_iproc - Swapped primary and secondary isr handlers. * ltr501 - Fix swapped als/ps register fields when enabling interrupts * max9611 - Wrong scale factor for the shunt_resistor attribute. * sun4-gpadc - Module autoloading fixes by adding the device table declarations. - Fix parent device being used in devm functions. 
Jonathan writes:

First set of IIO fixes in the 4.12 cycle.

Matt finally set up the lightning storm he needed to test the as3935.

* core
  - Fix a null pointer deference in iio_trigger_write_current when changing
  from a non existent trigger to another non existent trigger.
* a3935
  - Recalibrate the RCO after resume.
  - Fix interrupt mask so that we actually get some interrupts.
  - Use iio_trigger_poll_chained as we aren't in interrupt context.
* am335x
  - Fix wrong allocation size provided for private data to iio_device_alloc.
* bcm_iproc
  - Swapped primary and secondary isr handlers.
* ltr501
  - Fix swapped als/ps register fields when enabling interrupts
* max9611
  - Wrong scale factor for the shunt_resistor attribute.
* sun4-gpadc
  - Module autoloading fixes by adding the device table declarations.
  - Fix parent device being used in devm functions.
iio: adc: sun4i-gpadc-iio: fix parent device being used in devm function 2017-05-21T14:17:40+00:00 Quentin Schulz quentin.schulz@free-electrons.com 2017-05-18T06:36:07+00:00 82237f268281d338aa35cd014be8ffb0b5445482 For the sake of DT binding stability, this IIO driver is a child of an MFD driver for Allwinner A10, A13 and A31 because there already exists a DT binding for this IP. The MFD driver has a DT node but the IIO driver does not. The IIO device registers the temperature sensor in the thermal framework using the DT node of the parent, the MFD device, so the thermal framework could match the phandle to the MFD device in the DT and the struct device used to register in the thermal framework. devm_thermal_zone_of_sensor_register was previously used to register the thermal sensor with the parent struct device of the IIO device, representing the MFD device. By doing so, we registered actually the parent in the devm routine and not the actual IIO device. This lead to the devm unregister function not being called when the IIO module driver is removed. It resulted in the thermal framework still polling the get_temp function of the IIO module while the device doesn't exist anymore, thus generated a kernel panic. Use the non-devm function instead and do the unregister manually in the remove function. Fixes: d1caa9905538 ("iio: adc: add support for Allwinner SoCs ADC") Signed-off-by: Quentin Schulz <quentin.schulz@free-electrons.com> Reported-by: Corentin Labbe <clabbe.montjoie@gmail.com> Reviewed-by: Maxime Ripard <maxime.ripard@free-electrons.com> Signed-off-by: Jonathan Cameron <jic23@kernel.org> 
For the sake of DT binding stability, this IIO driver is a child of an
MFD driver for Allwinner A10, A13 and A31 because there already exists a
DT binding for this IP. The MFD driver has a DT node but the IIO driver
does not.

The IIO device registers the temperature sensor in the thermal framework
using the DT node of the parent, the MFD device, so the thermal
framework could match the phandle to the MFD device in the DT and the
struct device used to register in the thermal framework.

devm_thermal_zone_of_sensor_register was previously used to register the
thermal sensor with the parent struct device of the IIO device,
representing the MFD device. By doing so, we registered actually the
parent in the devm routine and not the actual IIO device.

This lead to the devm unregister function not being called when the IIO
module driver is removed. It resulted in the thermal framework still
polling the get_temp function of the IIO module while the device doesn't
exist anymore, thus generated a kernel panic.

Use the non-devm function instead and do the unregister manually in the
remove function.

Fixes: d1caa9905538 ("iio: adc: add support for Allwinner SoCs ADC")

Signed-off-by: Quentin Schulz <quentin.schulz@free-electrons.com>
Reported-by: Corentin Labbe <clabbe.montjoie@gmail.com>
Reviewed-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
iio: light: ltr501 Fix interchanged als/ps register field 2017-05-21T13:47:39+00:00 Franziska Naepelt franziska.naepelt@idt.com 2017-05-17T10:41:19+00:00 7cc3bff4efe6164a0c8163331c8aa55454799f42 The register mapping for the IIO driver for the Liteon Light and Proximity sensor LTR501 interrupt mode is interchanged (ALS/PS). There is a register called INTERRUPT register (address 0x8F) Bit 0 represents PS measurement trigger. Bit 1 represents ALS measurement trigger. This two bit fields are interchanged within the driver. see datasheet page 24: http://optoelectronics.liteon.com/upload/download/DS86-2012-0006/S_110_LTR-501ALS-01_PrelimDS_ver1%5B1%5D.pdf Signed-off-by: Franziska Naepelt <franziska.naepelt@idt.com> Fixes: 7ac702b3144b6 ("iio: ltr501: Add interrupt support") Acked-by: Peter Meerwald-Stadler <pmeerw@pmeerw.net> Cc: <Stable@vger.kernel.org> Signed-off-by: Jonathan Cameron <jic23@kernel.org> 
The register mapping for the IIO driver for the Liteon Light and Proximity
sensor LTR501 interrupt mode is interchanged (ALS/PS).
There is a register called INTERRUPT register (address 0x8F)
Bit 0 represents PS measurement trigger.
Bit 1 represents ALS measurement trigger.
This two bit fields are interchanged within the driver.
see datasheet page 24:
http://optoelectronics.liteon.com/upload/download/DS86-2012-0006/S_110_LTR-501ALS-01_PrelimDS_ver1%5B1%5D.pdf

Signed-off-by: Franziska Naepelt <franziska.naepelt@idt.com>
Fixes: 7ac702b3144b6 ("iio: ltr501: Add interrupt support")
Acked-by: Peter Meerwald-Stadler <pmeerw@pmeerw.net>
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
iio: adc: bcm_iproc_adc: swap primary and secondary isr handler's 2017-05-21T12:01:17+00:00 Raveendra Padasalagi raveendra.padasalagi@broadcom.com 2017-05-16T06:52:42+00:00 f7d86ecf83cb66d3c4c6ac4edb1dd50c0919aa2b The third argument of devm_request_threaded_irq() is the primary handler. It is called in hardirq context and checks whether the interrupt is relevant to the device. If the primary handler returns IRQ_WAKE_THREAD, the secondary handler (a.k.a. handler thread) is scheduled to run in process context. bcm_iproc_adc.c uses the secondary handler as the primary one and the other way around. So this patch fixes the same, along with re-naming the secondary handler and primary handler names properly. Tested on the BCM9583XX iProc SoC based boards. Fixes: 4324c97ecedc ("iio: Add driver for Broadcom iproc-static-adc") Reported-by: Pavel Roskin <plroskin@gmail.com> Signed-off-by: Raveendra Padasalagi <raveendra.padasalagi@broadcom.com> Cc: stable@vger.kernel.org Signed-off-by: Jonathan Cameron <jic23@kernel.org> 
The third argument of devm_request_threaded_irq() is the primary
handler. It is called in hardirq context and checks whether the
interrupt is relevant to the device. If the primary handler returns
IRQ_WAKE_THREAD, the secondary handler (a.k.a. handler thread) is
scheduled to run in process context.

bcm_iproc_adc.c uses the secondary handler as the primary one
and the other way around. So this patch fixes the same, along with
re-naming the secondary handler and primary handler names properly.

Tested on the BCM9583XX iProc SoC based boards.

Fixes: 4324c97ecedc ("iio: Add driver for Broadcom iproc-static-adc")
Reported-by: Pavel Roskin <plroskin@gmail.com>
Signed-off-by: Raveendra Padasalagi <raveendra.padasalagi@broadcom.com>
Cc: stable@vger.kernel.org
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
iio: trigger: fix NULL pointer dereference in iio_trigger_write_current() 2017-05-21T11:36:59+00:00 Marcin Niestroj m.niestroj@grinn-global.com 2017-05-18T07:12:06+00:00 4eecbe81885180c9f6217ecfd679b1f285967218 In case oldtrig == trig == NULL (which happens when we set none trigger, when there is already none set) there is a NULL pointer dereference during iio_trigger_put(trig). Below is kernel output when this occurs: [ 26.741790] Unable to handle kernel NULL pointer dereference at virtual address 00000000 [ 26.750179] pgd = cacc0000 [ 26.752936] [00000000] *pgd=8adc6835, *pte=00000000, *ppte=00000000 [ 26.759531] Internal error: Oops: 17 [#1] SMP ARM [ 26.764261] Modules linked in: usb_f_ncm u_ether usb_f_acm u_serial usb_f_fs libcomposite configfs evbug [ 26.773844] CPU: 0 PID: 152 Comm: synchro Not tainted 4.12.0-rc1 #2 [ 26.780128] Hardware name: Freescale i.MX6 Ultralite (Device Tree) [ 26.786329] task: cb1de200 task.stack: cac92000 [ 26.790892] PC is at iio_trigger_write_current+0x188/0x1f4 [ 26.796403] LR is at lock_release+0xf8/0x20c [ 26.800696] pc : [<c0736f34>] lr : [<c016efb0>] psr: 600d0013 [ 26.800696] sp : cac93e30 ip : cac93db0 fp : cac93e5c [ 26.812193] r10: c0e64fe8 r9 : 00000000 r8 : 00000001 [ 26.817436] r7 : cb190810 r6 : 00000010 r5 : 00000001 r4 : 00000000 [ 26.823982] r3 : 00000000 r2 : 00000000 r1 : cb1de200 r0 : 00000000 [ 26.830528] Flags: nZCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment none [ 26.837683] Control: 10c5387d Table: 8acc006a DAC: 00000051 [ 26.843448] Process synchro (pid: 152, stack limit = 0xcac92210) [ 26.849475] Stack: (0xcac93e30 to 0xcac94000) [ 26.853857] 3e20: 00000001 c0736dac c054033c cae6b680 [ 26.862060] 3e40: cae6b680 00000000 00000001 cb3f8610 cac93e74 cac93e60 c054035c c0736db8 [ 26.870264] 3e60: 00000001 c054033c cac93e94 cac93e78 c029bf34 c0540348 00000000 00000000 [ 26.878469] 3e80: cb3f8600 cae6b680 cac93ed4 cac93e98 c029b320 c029bef0 00000000 00000000 [ 26.886672] 3ea0: 00000000 cac93f78 cb2d41fc caed3280 c029b214 cac93f78 00000001 000e20f8 [ 26.894874] 3ec0: 00000001 00000000 cac93f44 cac93ed8 c0221dcc c029b220 c0e1ca39 cb2d41fc [ 26.903079] 3ee0: cac93f04 cac93ef0 c0183ef0 c0183ab0 cb2d41fc 00000000 cac93f44 cac93f08 [ 26.911282] 3f00: c0225eec c0183ebc 00000001 00000000 c0223728 00000000 c0245454 00000001 [ 26.919485] 3f20: 00000001 caed3280 000e20f8 cac93f78 000e20f8 00000001 cac93f74 cac93f48 [ 26.927690] 3f40: c0223680 c0221da4 c0246520 c0245460 caed3283 caed3280 00000000 00000000 [ 26.935893] 3f60: 000e20f8 00000001 cac93fa4 cac93f78 c0224520 c02235e4 00000000 00000000 [ 26.944096] 3f80: 00000001 000e20f8 00000001 00000004 c0107f84 cac92000 00000000 cac93fa8 [ 26.952299] 3fa0: c0107de0 c02244e8 00000001 000e20f8 0000000e 000e20f8 00000001 fbad2484 [ 26.960502] 3fc0: 00000001 000e20f8 00000001 00000004 beb6b698 00064260 0006421c beb6b4b4 [ 26.968705] 3fe0: 00000000 beb6b450 b6f219a0 b6e2f268 800d0010 0000000e cac93ff4 cac93ffc [ 26.976896] Backtrace: [ 26.979388] [<c0736dac>] (iio_trigger_write_current) from [<c054035c>] (dev_attr_store+0x20/0x2c) [ 26.988289] r10:cb3f8610 r9:00000001 r8:00000000 r7:cae6b680 r6:cae6b680 r5:c054033c [ 26.996138] r4:c0736dac r3:00000001 [ 26.999747] [<c054033c>] (dev_attr_store) from [<c029bf34>] (sysfs_kf_write+0x50/0x54) [ 27.007686] r5:c054033c r4:00000001 [ 27.011290] [<c029bee4>] (sysfs_kf_write) from [<c029b320>] (kernfs_fop_write+0x10c/0x224) [ 27.019579] r7:cae6b680 r6:cb3f8600 r5:00000000 r4:00000000 [ 27.025271] [<c029b214>] (kernfs_fop_write) from [<c0221dcc>] (__vfs_write+0x34/0x120) [ 27.033214] r10:00000000 r9:00000001 r8:000e20f8 r7:00000001 r6:cac93f78 r5:c029b214 [ 27.041059] r4:caed3280 [ 27.043622] [<c0221d98>] (__vfs_write) from [<c0223680>] (vfs_write+0xa8/0x170) [ 27.050959] r9:00000001 r8:000e20f8 r7:cac93f78 r6:000e20f8 r5:caed3280 r4:00000001 [ 27.058731] [<c02235d8>] (vfs_write) from [<c0224520>] (SyS_write+0x44/0x98) [ 27.065806] r9:00000001 r8:000e20f8 r7:00000000 r6:00000000 r5:caed3280 r4:caed3283 [ 27.073582] [<c02244dc>] (SyS_write) from [<c0107de0>] (ret_fast_syscall+0x0/0x1c) [ 27.081179] r9:cac92000 r8:c0107f84 r7:00000004 r6:00000001 r5:000e20f8 r4:00000001 [ 27.088947] Code: 1a000009 e1a04009 e3a06010 e1a05008 (e5943000) [ 27.095244] ---[ end trace 06d1dab86d6e6bab ]--- To fix that problem call iio_trigger_put(trig) only when trig is not NULL. Fixes: d5d24bcc0a10 ("iio: trigger: close race condition in acquiring trigger reference") Signed-off-by: Marcin Niestroj <m.niestroj@grinn-global.com> Cc: <Stable@vger.kernel.org> Signed-off-by: Jonathan Cameron <jic23@kernel.org> 
In case oldtrig == trig == NULL (which happens when we set none
trigger, when there is already none set) there is a NULL pointer
dereference during iio_trigger_put(trig). Below is kernel output when
this occurs:

[   26.741790] Unable to handle kernel NULL pointer dereference at virtual address 00000000
[   26.750179] pgd = cacc0000
[   26.752936] [00000000] *pgd=8adc6835, *pte=00000000, *ppte=00000000
[   26.759531] Internal error: Oops: 17 [#1] SMP ARM
[   26.764261] Modules linked in: usb_f_ncm u_ether usb_f_acm u_serial usb_f_fs libcomposite configfs evbug
[   26.773844] CPU: 0 PID: 152 Comm: synchro Not tainted 4.12.0-rc1 #2
[   26.780128] Hardware name: Freescale i.MX6 Ultralite (Device Tree)
[   26.786329] task: cb1de200 task.stack: cac92000
[   26.790892] PC is at iio_trigger_write_current+0x188/0x1f4
[   26.796403] LR is at lock_release+0xf8/0x20c
[   26.800696] pc : [<c0736f34>]    lr : [<c016efb0>]    psr: 600d0013
[   26.800696] sp : cac93e30  ip : cac93db0  fp : cac93e5c
[   26.812193] r10: c0e64fe8  r9 : 00000000  r8 : 00000001
[   26.817436] r7 : cb190810  r6 : 00000010  r5 : 00000001  r4 : 00000000
[   26.823982] r3 : 00000000  r2 : 00000000  r1 : cb1de200  r0 : 00000000
[   26.830528] Flags: nZCv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment none
[   26.837683] Control: 10c5387d  Table: 8acc006a  DAC: 00000051
[   26.843448] Process synchro (pid: 152, stack limit = 0xcac92210)
[   26.849475] Stack: (0xcac93e30 to 0xcac94000)
[   26.853857] 3e20:                                     00000001 c0736dac c054033c cae6b680
[   26.862060] 3e40: cae6b680 00000000 00000001 cb3f8610 cac93e74 cac93e60 c054035c c0736db8
[   26.870264] 3e60: 00000001 c054033c cac93e94 cac93e78 c029bf34 c0540348 00000000 00000000
[   26.878469] 3e80: cb3f8600 cae6b680 cac93ed4 cac93e98 c029b320 c029bef0 00000000 00000000
[   26.886672] 3ea0: 00000000 cac93f78 cb2d41fc caed3280 c029b214 cac93f78 00000001 000e20f8
[   26.894874] 3ec0: 00000001 00000000 cac93f44 cac93ed8 c0221dcc c029b220 c0e1ca39 cb2d41fc
[   26.903079] 3ee0: cac93f04 cac93ef0 c0183ef0 c0183ab0 cb2d41fc 00000000 cac93f44 cac93f08
[   26.911282] 3f00: c0225eec c0183ebc 00000001 00000000 c0223728 00000000 c0245454 00000001
[   26.919485] 3f20: 00000001 caed3280 000e20f8 cac93f78 000e20f8 00000001 cac93f74 cac93f48
[   26.927690] 3f40: c0223680 c0221da4 c0246520 c0245460 caed3283 caed3280 00000000 00000000
[   26.935893] 3f60: 000e20f8 00000001 cac93fa4 cac93f78 c0224520 c02235e4 00000000 00000000
[   26.944096] 3f80: 00000001 000e20f8 00000001 00000004 c0107f84 cac92000 00000000 cac93fa8
[   26.952299] 3fa0: c0107de0 c02244e8 00000001 000e20f8 0000000e 000e20f8 00000001 fbad2484
[   26.960502] 3fc0: 00000001 000e20f8 00000001 00000004 beb6b698 00064260 0006421c beb6b4b4
[   26.968705] 3fe0: 00000000 beb6b450 b6f219a0 b6e2f268 800d0010 0000000e cac93ff4 cac93ffc
[   26.976896] Backtrace:
[   26.979388] [<c0736dac>] (iio_trigger_write_current) from [<c054035c>] (dev_attr_store+0x20/0x2c)
[   26.988289]  r10:cb3f8610 r9:00000001 r8:00000000 r7:cae6b680 r6:cae6b680 r5:c054033c
[   26.996138]  r4:c0736dac r3:00000001
[   26.999747] [<c054033c>] (dev_attr_store) from [<c029bf34>] (sysfs_kf_write+0x50/0x54)
[   27.007686]  r5:c054033c r4:00000001
[   27.011290] [<c029bee4>] (sysfs_kf_write) from [<c029b320>] (kernfs_fop_write+0x10c/0x224)
[   27.019579]  r7:cae6b680 r6:cb3f8600 r5:00000000 r4:00000000
[   27.025271] [<c029b214>] (kernfs_fop_write) from [<c0221dcc>] (__vfs_write+0x34/0x120)
[   27.033214]  r10:00000000 r9:00000001 r8:000e20f8 r7:00000001 r6:cac93f78 r5:c029b214
[   27.041059]  r4:caed3280
[   27.043622] [<c0221d98>] (__vfs_write) from [<c0223680>] (vfs_write+0xa8/0x170)
[   27.050959]  r9:00000001 r8:000e20f8 r7:cac93f78 r6:000e20f8 r5:caed3280 r4:00000001
[   27.058731] [<c02235d8>] (vfs_write) from [<c0224520>] (SyS_write+0x44/0x98)
[   27.065806]  r9:00000001 r8:000e20f8 r7:00000000 r6:00000000 r5:caed3280 r4:caed3283
[   27.073582] [<c02244dc>] (SyS_write) from [<c0107de0>] (ret_fast_syscall+0x0/0x1c)
[   27.081179]  r9:cac92000 r8:c0107f84 r7:00000004 r6:00000001 r5:000e20f8 r4:00000001
[   27.088947] Code: 1a000009 e1a04009 e3a06010 e1a05008 (e5943000)
[   27.095244] ---[ end trace 06d1dab86d6e6bab ]---

To fix that problem call iio_trigger_put(trig) only when trig is not
NULL.

Fixes: d5d24bcc0a10 ("iio: trigger: close race condition in acquiring trigger reference")
Signed-off-by: Marcin Niestroj <m.niestroj@grinn-global.com>
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>