If an IIO device returns an error code for a read access via debugfs, it
is currently ignored by the IIO core (other than emitting an error
message). Instead, return this error code to user space, so upper layers
can detect it correctly.
Signed-off-by: Matt Fornero <matt.fornero@mathworks.com>
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

The serial interface can be reset by writing 32 consecutive 1s to the device.
'ret' was initialized correctly but its value was overwritten when
ad7793_check_platform_data() was called. Since a dedicated reset function
is present now, it should be used instead.

Fixes: 2edb769d ("iio:ad7793: Add support for the ad7798 and ad7799")
Signed-off-by: Dragos Bogdan <dragos.bogdan@analog.com>
Acked-by: Lars-Peter Clausen <lars@metafoo.de>
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

Since most of the SD ADCs have the option of reseting the serial
interface by sending a number of SCLKs with CS = 0 and DIN = 1,
a dedicated function that can do this is usefull.

Needed for the patch:  iio: ad7793: Fix the serial interface reset
Signed-off-by: Dragos Bogdan <dragos.bogdan@analog.com>
Acked-by: Lars-Peter Clausen <lars@metafoo.de>
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

The ctrl_reg register needs to be written after any write to
the humidity registers. The value written to the ctrl_reg register
does not necessarily need to change, but a write operation must
occur.

The regmap_update_bits functions will not write to a register
if the register value matches the value to be written. This saves
unnecessary bus operations.  The change in this patch forces a bus
write during the chip_config operation by switching to
regmap_write_bits.

This will fix issues where the Humidity Sensor Oversampling bits
are not updated after initialization.
Signed-off-by: Colin Parker <colin.parker@aclima.io>
Acked-by: Andreas Klinger <ak@it-klinger.de>
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

Commit f686a36b ("iio: adc: mcp320x: Add support for mcp3301")
returns a signed voltage from mcp320x_adc_conversion() but neglects that
the caller interprets a negative return value as failure.  Only mcp3301
(and the upcoming mcp3550/1/3) is affected as the other chips are
incapable of measuring negative voltages.

Fix and while at it, add mcp3301 to the list of supported chips at the
top of the file.

Fixes: f686a36b ("iio: adc: mcp320x: Add support for mcp3301")
Cc: Andrea Galbusera <gizero@gmail.com>
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

The driver calls spi_get_drvdata() in its ->remove hook even though it
has never called spi_set_drvdata().  Stack trace for posterity:

Unable to handle kernel NULL pointer dereference at virtual address 00000220
Internal error: Oops: 5 [#1] SMP ARM
[<8072f564>] (mutex_lock) from [<7f1400d0>] (iio_device_unregister+0x24/0x7c [industrialio])
[<7f1400d0>] (iio_device_unregister [industrialio]) from [<7f15e020>] (mcp320x_remove+0x20/0x30 [mcp320x])
[<7f15e020>] (mcp320x_remove [mcp320x]) from [<8055a8cc>] (spi_drv_remove+0x2c/0x44)
[<8055a8cc>] (spi_drv_remove) from [<805087bc>] (__device_release_driver+0x98/0x134)
[<805087bc>] (__device_release_driver) from [<80509180>] (driver_detach+0xdc/0xe0)
[<80509180>] (driver_detach) from [<8050823c>] (bus_remove_driver+0x5c/0xb0)
[<8050823c>] (bus_remove_driver) from [<80509ab0>] (driver_unregister+0x38/0x58)
[<80509ab0>] (driver_unregister) from [<7f15e69c>] (mcp320x_driver_exit+0x14/0x1c [mcp320x])
[<7f15e69c>] (mcp320x_driver_exit [mcp320x]) from [<801a78d0>] (SyS_delete_module+0x184/0x1d0)
[<801a78d0>] (SyS_delete_module) from [<80108100>] (ret_fast_syscall+0x0/0x1c)

Fixes: f5ce4a7a ("iio: adc: add driver for MCP3204/08 12-bit ADC")
Cc: Oskar Andero <oskar.andero@gmail.com>
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

Fix a bad error check when counting 'st,adc-channels' array elements.
This is seen when all channels are in use simultaneously.

Fixes: 64ad7f64 ("iio: adc: stm32: introduce compatible data cfg")
Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

Balance timer start routine that sets ARPE: clear it in stop routine.
This fixes a corner case, when timer is used successively as trigger
(with sampling_frequency start/stop routines), then as a counter
(with preset).

Fixes: 93fbe91b ("iio: Add STM32 timer trigger driver")
Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

Currently, setting preset value (ARR) will update directly 'Auto reload
value' only on 1st write access. But then, ARPE is set. This makes
ARR a shadow register. Preset value should be updated upon each
write request: ensure ARPE is 0. This fixes successive writes to
preset attribute.

Fixes: 4adec7da ("iio: stm32 trigger: Add quadrature encoder device")
Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: adc: twl4030: Return an error if we can not enable the vusb3v1 regulator in 'twl4030_madc_probe()'

If we can not enable the regulator, go through the error handling path
instead of silently continuing.

Fixes: 7cc97d77 ("iio: adc: twl4030: Fix ADC[3:6] readings")
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: adc: twl4030: Disable the vusb3v1 rugulator in the error handling path of 'twl4030_madc_probe()'

Commit 7cc97d77 has introduced a call to 'regulator_disable()' in the
.remove function.
So we should also have such a call in the .probe function in case of
error after a successful 'regulator_enable()' call.

Add a new label for that and use it.

Fixes: 7cc97d77 ("iio: adc: twl4030: Fix ADC[3:6] readings")
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

If 'devm_regulator_get()' fails, we should go through the existing error
handling path instead of returning directly, as done is all the other
error handling paths in this function.

Fixes: 7cc97d77 ("iio: adc: twl4030: Fix ADC[3:6] readings")
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

Data-ready line in LIS3MDL is routed to drdy pin and it is not possible
to select a different INT pin. st_sensors_set_dataready_irq() assumes
that if drdy int address is not exported in register map, irq trigger
is not supported by the sensor and hw_irq_trigger is always false.
Based on this configuration st_sensors_irq_thread does not consume
generated interrupt causing an unhandled irq.
Fix this taking into account status register address in
st_sensors_set_dataready_irq()

Fixes: 90efe055 (iio: st_sensors: harden interrupt handling)
Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi@st.com>
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

The comparator polarity field in config register is not correctly
initialized as per the interrupt trigger setting.  Because the bitfield
definision is wrong and bit shifting is missed.

Fixes: d9f39bab ("iio: adc: ti-ads1015: add threshold event support")
Cc: Daniel Baluta <daniel.baluta@gmail.com>
Cc: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

This commit adds the TODO file and implements some reviewers comments
made against some patches to the wireless tree.
Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
Cc: Ping-Ke Shih <pkshih@realtek.com>
Cc: Yan-Hsuan Chuang <yhchuang@realtek.com>
Cc: Birming Chiu <birming@realtek.com>
Cc: Shaofu <shaofu@realtek.com>
Cc: Steven Ting <steventing@realtek.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

The RTL8822BE, an 802.11ac wireless network card, is now appearing in
new computers. Its driver is being placed in staging to reduce the time
that users of this new card will have access to in-kernel drivers.

This commit enables building of the new driver. For this version, all
routines are built into a single module r8822be. When this driver is
moved to the wireless tree, halmac, phydm, and rtl8822be will become
new modules.
Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
Cc: Ping-Ke Shih <pkshih@realtek.com>
Cc: Yan-Hsuan Chuang <yhchuang@realtek.com>
Cc: Birming Chiu <birming@realtek.com>
Cc: Shaofu <shaofu@realtek.com>
Cc: Steven Ting <steventing@realtek.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

The RTL8822BE, an 802.11ac wireless network card, is now appearing in
new computers. Its driver is being placed in staging to reduce the time
that users of this new card will have access to in-kernel drivers.

This commit adds the code for the new r8822be driver.
Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
Cc: Yan-Hsuan Chuang <yhchuang@realtek.com>
Cc: Birming Chiu <birming@realtek.com>
Cc: Shaofu <shaofu@realtek.com>
Cc: Steven Ting <steventing@realtek.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

The RTL8822BE, an 802.11ac wireless network card, is now appearing in
new computers. Its driver is being placed in staging to reduce the time
that users of this new card will have access to in-kernel drivers.

New Realtek wireless devices have a new method for PHY control and
dynamic management. The RTL8822BE is the first of these devices, thus
there is additional code required.

In the final version, this code will be a separate module; however,
it is combined with the r8822be driver to minimize the interference
with the drivers in the wireless tree.
Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
Cc: Yan-Hsuan Chuang <yhchuang@realtek.com>
Cc: Birming Chiu <birming@realtek.com>
Cc: Shaofu <shaofu@realtek.com>
Cc: Steven Ting <steventing@realtek.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

The RTL8822BE, an 802.11ac wireless network card, is now appearing in
new computers. Its driver is being placed in staging to reduce the time
that users of this new card will have access to in-kernel drivers.

New Realtek devices implement a common sub-driver to control the MAC
layer. The RTL8822BE is the first of these devices, thus its introduction
involves some extra code. In the wireless tree, this will be a separate
module; however, it is compiled into the 8822be driver here.
Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
Cc: Yan-Hsuan Chuang <yhchuang@realtek.com>
Cc: Birming Chiu <birming@realtek.com>
Cc: Shaofu <shaofu@realtek.com>
Cc: Steven Ting <steventing@realtek.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

The RTL8822BE, an 802.11ac wireless network card, is now appearing in
new computers. Its driver is being placed in staging to reduce the time
that users of this new card will have access to in-kernel drivers.

This commit adds the routines needed for BT coexistence with the
new driver.
Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
Cc: Yan-Hsuan Chuang <yhchuang@realtek.com>
Cc: Birming Chiu <birming@realtek.com>
Cc: Shaofu <shaofu@realtek.com>
Cc: Steven Ting <steventing@realtek.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

The RTL8822BE, an 802.11ac wireless network card, is now appearing in
new computers. Its driver is being placed in staging to reduce the time
that users of this new card will have access to in-kernel drivers.

This commit copies the existing routines from .../rtlwifi/btcoexist/
into staging. There are no changes other than removing all EXPORT
statements, and the fixing of checkpatch messages. The latter will
be backported to the wireless tree.
Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
Cc: Ping-Ke Shih <pkshih@realtek.com>
Cc: Yan-Hsuan Chuang <yhchuang@realtek.com>
Cc: Birming Chiu <birming@realtek.com>
Cc: Shaofu <shaofu@realtek.com>
Cc: Steven Ting <steventing@realtek.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

The RTL8822BE, an 802.11ac wireless network card, is now appearing in
new computers. Its driver is being placed in staging to reduce the time
that users of this new card will have access to in-kernel drivers.

This commit copies the code that currently constitutes the rtlwifi and
rtl_pci mini drivers. This material is copied into staging to prevent
any undo interaction between the existing drivers and this new one.
The only changes in this code are the removal of all export statements,
and the fixing of some checkpatch messages. The latter will be backported
into the wireless tree.
Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
Cc: Yan-Hsuan Chuang <yhchuang@realtek.com>
Cc: Birming Chiu <birming@realtek.com>
Cc: Shaofu <shaofu@realtek.com>
Cc: Steven Ting <steventing@realtek.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Refactor code to be more readable and eliminate the checkpatch
warning
Signed-off-by: Alex Briskin <br.shurik@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Fixed alignment so that it matched open parenthesis
Signed-off-by: Srishti Sharma <srishtishar@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Make this const as it is only stored in the type field of a device
structure, which is const.
Done using Coccinelle.
Signed-off-by: Bhumika Goyal <bhumirks@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

The mask of sns_key_info1 suggests the upper nybble is being extracted
however the following shift of 8 bits is too large and always results in
0.  Fix this by shifting only by 4 bits to correctly get the upper nybble.

Detected by CoverityScan, CID#142891 ("Operands don't affect result")

Fixes: fa590c22 ("staging: rts5208: add support for rts5208 and rts5288")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

space required before the open parenthesis, open brace should be
on previous line.
Signed-off-by: Xiangyang Zhang <xyz.sun.ok@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

checkpatch.pl gave
ERROR: open brace '{' following function definitions go on the next line.
Signed-off-by: Jamie Huang <jamienstar@163.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

We want to concatonate join string one, a '/' character, string two and
then a NUL terminator.  The destination buffer holds ori_gf->gf_pathlen
characters.  The strlen() function returns the number of characters not
counting the NUL terminator.  So we should be adding two extra spaces,
one for the foward slash and one for the NUL.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: John L. Hammond <john.hammond@intel.com>
Reviewed-by: frank zago <fzago@cray.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Merge tag 'iio-for-4.14b' of git://git.kernel.org/pub/scm/linux/kernel/git/jic23/iio into staging-next

Jonathan writes:

Second set of IIO new device support, features and cleanup for the 4.14 cycle.

New device support:
* ak8974
  - support the AMI306.
* st_magnetometer
  - add support for the LIS2MDL with bindings.
* rockchip-saradc
  - add binding for rv1108 SoC (no driver change).
* srf08
  - add srf02 (i2c only) and srf10 support.
* stm32-timer
  - support for the STM32H7 to existing driver.

Features:
* tools
  - move over to the tools buildsystem rather than hand rolling.
  - add an install section to the build.
* ak8974
  - use serial number to add device randomness.
  - add AMI306 calibration data output.
* ccs811
  - triggered buffer support.
* srf08
  - add a device tree table as the old style i2c probing is going away,
  - add triggered buffer support
* st32-adc
  - add optional st,min-sample-time-nsecs binding to allow control of
    sampling against analog circuitry.
* stm32-timer
  - add output compare triggers.
* ti-ads1015
  - add threshold event support.
* ti-ads7950
  - Allow use on ACPI platforms including providing a default reference
    voltage as there is no way to obtain this on ACPI currently.

Cleanup and fixes:
* ad7606
  - fix an error return code in probe.
* ads1015
  - fix incorrect data rate setting update when capture in progress,
  - fix wrong scale information for the ADS1115,
  - make conversions work when CONFIG_PM is not set,
  - make sure we don't get a stale result after a runtime resume by
    ensuring we wait long enough,
  - avoid returning a false error form the buffer setup callbacks,
  - add enough wait time to get the correct conversion,
  - remove an unnecessary config register update,
  - add a helper to set conversion mode reducing repeated boilerplate,
  - use devm_iio_triggered_buffer_setup to simplify error and remove
    paths,
  - use iio_device_claim_direct_mode instead of opencoding the same.
* ak8974
  - mark the INT_CLEAR register as precious to prevent debugfs access.
* apds9300
  - constify the i2c_device_id.
* at91-sama5 adc
  - add missing Kconfig dependency.
* bma180 accel
  - constify the i2c_device_id.
* rockchip_saradc
  - explicitly request exclusive reset control as part of the reset rework
    on going throughout the kernel.
* st_accel
  - fix drdy configuration for a load of accelerometers that only have
    the int1 line.  Fix is unimportant as presumably no deviec tree actually
    used the non existent hardware line.
* st_pressure
  - fix drdy configuration for LPS22HB and LPS25H by dropping int2 support
    as they don't have this. Fix is unimportant as presumably no device tree
    actually used the non existent hardware line.
* stm32-dac
  - explicitly request exclusive reset control (part of reset being reworked).
* tsl2583
  - constify the i2c_device_id.
* xadc
  - coding style fixes.

Commit a53e35db ("reset: Ensure drivers are explicit when requesting
reset lines") started to transition the reset control request API calls
to explicitly state whether the driver needs exclusive or shared reset
control behavior. Convert all drivers requesting exclusive resets to the
explicit API call so the temporary transition helpers can be removed.

No functional changes.

Cc: Jonathan Cameron <jic23@kernel.org>
Cc: Hartmut Knaack <knaack.h@gmx.de>
Cc: Lars-Peter Clausen <lars@metafoo.de>
Cc: Peter Meerwald-Stadler <pmeerw@pmeerw.net>
Cc: Heiko Stuebner <heiko@sntech.de>
Cc: linux-iio@vger.kernel.org
Cc: linux-rockchip@lists.infradead.org
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

Commit a53e35db ("reset: Ensure drivers are explicit when requesting
reset lines") started to transition the reset control request API calls
to explicitly state whether the driver needs exclusive or shared reset
control behavior. Convert all drivers requesting exclusive resets to the
explicit API call so the temporary transition helpers can be removed.

No functional changes.

Cc: Jonathan Cameron <jic23@kernel.org>
Cc: Hartmut Knaack <knaack.h@gmx.de>
Cc: Lars-Peter Clausen <lars@metafoo.de>
Cc: Peter Meerwald-Stadler <pmeerw@pmeerw.net>
Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Cc: Alexandre Torgue <alexandre.torgue@st.com>
Cc: linux-iio@vger.kernel.org
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

The ADS1015 device provides programmable comparator that can issue an
interrupt on the ALERT pin.  This change adds the iio threshold event
support for that feature.

The ADS1015 device only have a single config register which contains an
input multiplexer selection, comparator settings, and etc.  So only a
single event channel can be enabled at a time.  Also enabling both buffer
and event are prohibited for simplicity.

Cc: Daniel Baluta <daniel.baluta@gmail.com>
Cc: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

While the iio buffer for the ti-ads1015 driver is enabled, reading the
raw ADC channel data is restricted.  We usually use the
iio_device_claim_direct_mode()/iio_device_release_direct_mode() pair for
that.

This change consequently reverses the locking order for the driver's
private lock and indio_dev->mlock which acquired by
iio_device_claim_direct_mode() internally. But it's safe because there is
no other dependency between these locks.

Cc: Daniel Baluta <daniel.baluta@gmail.com>
Cc: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

Use devm_iio_triggered_buffer_setup to simplify the error path in the
probe() and remove() function.

This changes the remove order, but the end result of remove function
actually does the reverse of probe.

Cc: Daniel Baluta <daniel.baluta@gmail.com>
Cc: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

This adds a helper function to set conversion mode as there are a fair
number of users.

Cc: Daniel Baluta <daniel.baluta@gmail.com>
Cc: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

The ti-ads1015 driver has eight iio voltage channels and each iio channel
can hold own scale information.

The ADS1015 device only have a single config register which contains an
input multiplexer selection, PGA and data rate settings.  So the driver
should load the correct settings when the input multiplexer selection is
changed.

However, regardless of which channlel is currently selected, changing any
iio channel's scale information immediately overwrites the current PGA
setting in the config register.

It is harmless because the correct PGA settings are reloaded just before
getting adc result anyway.  But it is unnecessary register update and
should be removed.

Cc: Daniel Baluta <daniel.baluta@gmail.com>
Cc: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

This driver assumes that the device is operating in the continuous
conversion mode which performs the conversion continuously.  So this driver
inserts a wait time before reading the conversion register if the
configuration is changed from a previous request.

Currently, the wait time is only the period required for a single
conversion that is calculated as the reciprocal of the sampling frequency.
However we also need to wait for the the previous conversion to complete.
Otherwise we probably get the conversion result for the previous
configuration when the sampling frequency is lower.

Cc: Daniel Baluta <daniel.baluta@gmail.com>
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

pm_runtime_get_sync() and pm_runtime_put_autosuspend() return 0 on
success, 1 if the device's runtime PM status was already requested status
or error code on failure.  So a positive return value doesn't indicate an
error condition.

However, any non-zero return values from buffer preenable and postdisable
callbacks are recognized as an error and this driver reuses the return
value from pm_runtime_get_sync() and pm_runtime_put_autosuspend() in
these callbacks.  This change fixes the false error detections.

Cc: Daniel Baluta <daniel.baluta@gmail.com>
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

This driver assumes that the device is operating in the continuous
conversion mode which performs the conversion continuously.  So this driver
doesn't insert a wait time before reading the conversion register if the
configuration is not changed from a previous request.

This assumption is broken if the device is runtime suspended and entered
a power-down state.  The forthcoming request causes reading a stale result
from the conversion register as the device is runtime resumed just before.

Fix it by adding a flag to detect that condition and insert a necessary
wait time.

Cc: Daniel Baluta <daniel.baluta@gmail.com>
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>