Some chips either don't support it or fail to provide adequate documentation,
so sometimes it's impossible to enable the feature even if it is supported.
Signed-off-by: NLee Jones <lee.jones@linaro.org>
Acked-by: NDenis Ciocca <denis.ciocca@st.com>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

driver for the TSL4531 family of 16-bit I2C ambient light
sensors; information is here:
http://www.ams.com/eng/Products/Light-Sensors/Ambient-Light-Sensor-ALS/TSL45315

the chip offers simple lux output

v3 (thanks Lars-Peter Clausen):
* add mutex to when updating integration time
* fix chip ID checking
* code cleanups
v2:
* rename to tsl4351
* use INT_TIME
Signed-off-by: NPeter Meerwald <pmeerw@pmeerw.net>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

Signed-off-by: NPeter Meerwald <pmeerw@pmeerw.net>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

Integration time is in seconds; it controls the measurement
time and influences the gain of a sensor.

There are two typical ways that scaling is implemented in a device:
1) input amplifier,
2) reference to the ADC is changed.
These both result in the accuracy of the ADC varying (by applying its
sampling over a more relevant range).

Integration time is a way of dealing with noise inherent in the analog
sensor itself.  In the case of a light sensor, a mixture of photon noise
and device specific noise.  Photon noise is dealt with by either improving
the efficiency of the sensor, (more photons actually captured) which is not
easily varied dynamically, or by integrating the measurement over a longer
time period.  Note that this can also be thought of as an averaging of a
number of individual samples and is infact sometimes implemented this way.
Altering integration time implies that the duration of a measurement changes,
a fact the device's user may be interested in.

Hence it makes sense to distinguish between integration time and simple
scale. In some devices both types of control are present and whilst they
will have similar effects on the amplitude of the reading, their effect
on the noise of the measurements will differ considerably.

Used by adjd_s311, tsl4531, tcs3472
The following drivers have similar controls (and could be adapted):
* tsl2563 (integration time is controlled via CALIBSCALE among other things)
* tsl2583 (has integration_time device_attr, but driver doesn't use channels yet)
* tsl2x7x (has integration_time attr)
Signed-off-by: NPeter Meerwald <pmeerw@pmeerw.net>
Cc: Jon Brenner <jon.brenner@ams.com>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

devm_iio_device_alloc makes code simpler.
Signed-off-by: NSachin Kamat <sachin.kamat@linaro.org>
Cc: Barry Song <21cnbao@gmail.com>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

devm_iio_device_alloc makes code simpler.
Signed-off-by: NSachin Kamat <sachin.kamat@linaro.org>
Cc: Barry Song <21cnbao@gmail.com>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

devm_iio_device_alloc makes code simpler.
Signed-off-by: NSachin Kamat <sachin.kamat@linaro.org>
Cc: Barry Song <21cnbao@gmail.com>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

devm_iio_device_alloc makes code simpler.
Signed-off-by: NSachin Kamat <sachin.kamat@linaro.org>
Cc: Barry Song <21cnbao@gmail.com>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

devm_iio_device_alloc makes code simpler.
Signed-off-by: NSachin Kamat <sachin.kamat@linaro.org>
Cc: Barry Song <21cnbao@gmail.com>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

devm_iio_device_alloc makes code simpler.
Signed-off-by: NSachin Kamat <sachin.kamat@linaro.org>
Cc: Graff Yang <graff.yang@gmail.com>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

devm_iio_device_alloc makes code simpler.
Signed-off-by: NSachin Kamat <sachin.kamat@linaro.org>
Cc: Graff Yang <graff.yang@gmail.com>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

dev_err is preferred over pr_err.
Signed-off-by: NSachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

devm_* APIs are device managed and make code simpler.
This patch also fixes the missing gpio_free call in remove.
Signed-off-by: NSachin Kamat <sachin.kamat@linaro.org>
Cc: Graff Yang <graff.yang@gmail.com>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

'break' after return is redundant. Remove it.
Signed-off-by: NSachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

'break' after return is redundant. Remove it.
Signed-off-by: NSachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

'break' after return is redundant. Remove it.
Signed-off-by: NSachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

'break' after return is redundant. Remove it.
Signed-off-by: NSachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

'break' after return is redundant. Remove it.
Signed-off-by: NSachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

Signed-off-by: NPeter Meerwald <pmeerw@pmeerw.net>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

Updated with the current one.
Signed-off-by: NSachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

Remove unnecessary work pending test before calling schedule_work().
It has been tested in queue_work_on() already. No functional changed.
Signed-off-by: NXie XiuQi <xiexiuqi@huawei.com>
Reviewed-by: NTejun Heo <tj@kernel.org>
Acked-by: NMichael Hennerich <michael.hennerich@analog.com>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

Add MODULE_ALIAS, so that auto module loading can work.
Signed-off-by: NFabio Estevam <fabio.estevam@freescale.com>
Acked-by: NMarek Vasut <marex@denx.de>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

Fix the order of resources removal in the error path of mxs_lradc_probe()
and also in mxs_lradc_remove().
Signed-off-by: NFabio Estevam <fabio.estevam@freescale.com>
Acked-by: NMarek Vasut <marex@denx.de>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

The usage of strict_strto*() is not preferred, because
strict_strto*() is obsolete. Thus, kstrto*() should be
used.

Previously, there were only strict_strtol(), strict_strtoul(),
strict_strtoull(), and strict_strtoll(). Thus, when converting
to the variables, only long, unsigned long, unsigned long long,
and long long can be used.

However, kstrto*() provides various functions handling all types
of variables. Therefore, the types of variables can be changed
properly.
Signed-off-by: NJingoo Han <jg1.han@samsung.com>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

Sysfs access to all channels.
Signed-off-by: NAngelo Compagnucci <angelo.compagnucci@gmail.com>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

Add a missing closing brace.
Signed-off-by: NSachin Kamat <sachin.kamat@linaro.org>
Cc: Shubhrajyoti Datta <shubhrajyoti@ti.com>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

Silences the following warning:
drivers/staging/iio/light/tsl2x7x_core.c:553:70:
warning: Using plain integer as NULL pointer
Signed-off-by: NSachin Kamat <sachin.kamat@linaro.org>
Cc: J. August Brenner <jbrenner@taosinc.com>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

devm_* APIs are device managed and make code simpler.
Signed-off-by: NSachin Kamat <sachin.kamat@linaro.org>
Cc: J. August Brenner <jbrenner@taosinc.com>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

devm_iio_device_alloc makes code simpler.
Signed-off-by: NSachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

devm_iio_device_alloc makes code simpler.
Signed-off-by: NSachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

devm_iio_device_alloc makes code simpler.
Signed-off-by: NSachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

devm_iio_device_alloc makes code simpler.
Signed-off-by: NSachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

devm_* APIs are device managed and make code simpler.
Signed-off-by: NSachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

devm_* APIs are device managed and make code simpler.
Signed-off-by: NSachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

devm_iio_device_alloc makes code simpler.
Signed-off-by: NSachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

devm_iio_device_alloc makes the code simple. While at it also
fixed an uninitialized return with -EINVAL.
Signed-off-by: NSachin Kamat <sachin.kamat@linaro.org>
Cc: J. August Brenner <jbrenner@taosinc.com>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

devm_* APIs are device managed and make code simpler.
Signed-off-by: NSachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

devm_* APIs are device managed and make code simpler.
Signed-off-by: NSachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

devm_* APIs are device managed and make code simpler.
This also fixes an error in return type during clk_get
failure.
Signed-off-by: NSachin Kamat <sachin.kamat@linaro.org>
Cc: Roland Stigge <stigge@antcom.de>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

devm_* APIs are device managed and make code simpler.
Signed-off-by: NSachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>