Now that open delay and sample delay for each channel is configurable
via DT, the default IDLE_TIMEOUT value is not enough as this is
calculated based on hardcoded macros. This results in driver returning
EBUSY sometimes. Fix this by increasing the timeout
value based on maximum value possible to open delay and sample delays
for each channel.

Fixes: 5dc11e81 ("iio: adc: ti_am335x_adc: make sample delay, open delay, averaging DT parameters")
Signed-off-by: NVignesh R <vigneshr@ti.com>
Acked-by: NLee Jones <lee.jones@linaro.org>
Cc: <Stable@vger.kernel.org>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

It is possible that two or more ADC channels can be simultaneously
requested for raw samples, in which case there can be race in access to
FIFO data resulting in loss of samples.
If am335x_tsc_se_set_once() is called again from tiadc_read_raw(), when
ADC is still acquired to sample one of the channels, the second process
might be put into uninterruptible sleep state. Fix these issues, by
protecting FIFO access and channel configurations with a mutex. Since
tiadc_read_raw() might take anywhere between few microseconds to few
milliseconds to finish execution (depending on averaging and delay
values supplied via DT), its better to use mutex instead of spinlock.

Fixes: 7ca6740c ("mfd: input: iio: ti_amm335x: Rework TSC/ADC synchronization")
Signed-off-by: NVignesh R <vigneshr@ti.com>
Cc: <Stable@vger.kernel.org>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

Replace ifdefs with SIMPLE_DEV_PM_OPS helper macro.
Signed-off-by: NAndrew F. Davis <afd@ti.com>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

Fix the code formatting to use the kernel preferred style
of using the actual variables to determize the size using
the sizeof() operator.
Signed-off-by: NAndrew F. Davis <afd@ti.com>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

Whilst this part has a hardware buffer, the identifcation that IIO cares
about is the userspace facing end.  It this case we push individual elements
from the hardware fifo into the software interface (specifically a kfifo)
rather than providing direct reads through to a hardware buffer
(as we still do in the sca3000 for example).

Technically the original specification as a hardware buffer could be
considered wrong, but it didn't matter until the patch listed below.

Result is that any attempt to enable the buffer will return -EINVAL

Fixes: 225d59ad ("iio: Specify supported modes for buffers")
Cc: <Stable@vger.kernel.org>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

Add optional DT properties to set open delay, sample delay and number
of averages per sample for each adc step. Open delay, sample delay
and averaging are some of the parameters that affect the sampling rate
and accuracy of the sample. Making these parameters configurable via
DT will help in balancing speed vs accuracy.
Signed-off-by: NVignesh R <vigneshr@ti.com>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

Refactor DT parsing into a separate function from probe() to
help addition of more DT parameters later.

No functional changes.
Signed-off-by: NVignesh R <vigneshr@ti.com>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

If the in-kernel push interface is used we may have a different masks
on the device buffer and the kernel buffer and in this case the device
should generate data for the reunion of the buffers, which is
available at indio_dev->active_scan_mask.

Compiled tested only except for bmc150-accel which was tested at
runtime with the hardware.
Signed-off-by: NOctavian Purdila <octavian.purdila@intel.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

This patch makes the initial changes required to workaround TSC-false
pen-up interrupts. It is required to implement these changes in order to
remove udelay in the TSC interrupt handler and false pen-up events.  The
charge step is to be executed immediately after sampling X+. Hence TSC is
made to use higher numbered steps (steps 5 to 16 for 5 co-ordinate
readouts, 4 wire TSC configuration) and ADC to use lower ones. Further X
co-ordinate readouts must be the last to be sampled, thus co-ordinates are
sampled in the order Y-Z-X.
Signed-off-by: NBrad Griffis <bgriffis@ti.com>
[vigneshr@ti.com: Ported the patch from v3.12 to v3.19rc1]
Signed-off-by: NVignesh R <vigneshr@ti.com>
Acked-by: NJonathan Cameron <jic23@kernel.org>
Signed-off-by: NDmitry Torokhov <dmitry.torokhov@gmail.com>

indio_dev was unused in function body plus some small style fix - add new
lines after "if(sth) return sth" and before the last return statement.

The argument was removed also in its client.
Signed-off-by: NKarol Wrona <k.wrona@samsung.com>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

Originally device and buffer registration were kept as separate operations
in IIO to allow to register two distinct sets of channels for buffered and
non-buffered operations. This has since already been further restricted and
the channel set registered for the buffer needs to be a subset of the
channel set registered for the device. Additionally the possibility to not
have a raw (or processed) attribute for a channel which was registered for
the device was added a while ago. This means it is possible to not register
any device level attributes for a channel even if it is registered for the
device. Also if a channel's scan_index is set to -1 and the channel is
registered for the buffer it is ignored.

So in summary it means it is possible to register the same channel array for
both the device and the buffer yet still end up with distinctive sets of
channels for both of them. This makes the argument for having to have to
manually register the channels for both the device and the buffer invalid.
Considering that the vast majority of all drivers want to register the same
set of channels for both the buffer and the device it makes sense to move
the buffer registration into the core to avoid some boiler-plate code in the
device driver setup path.
Signed-off-by: NLars-Peter Clausen <lars@metafoo.de>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

This patch removes the .owner field for drivers which use the
platform_driver_register api because this is overriden in
_platform_driver_register.
Signed-off-by: NSanjeev Sharma <Sanjeev_Sharma@mentor.com>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

Since AI lines could be selected at will (linux-3.11) the sending
and receiving ends of the FIFO does not agree about what step is used
for a line. It only works if the last lines are used, like 5,6,7,
and fails if ie 2,4,6 is selected in DT.
Signed-off-by: NJan Kardell <jan.kardell@telliq.com>
Tested-by: NZubair Lutfullah <zubair.lutfullah@gmail.com>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>
Cc: stable@vger.kernel.org

None of these files are actually using any __init type directives
and hence don't need to include <linux/init.h>.  Most are just a
left over from __devinit and __cpuinit removal, or simply due to
code getting copied from one driver to the next.
Signed-off-by: NPaul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

The ADC driver always programs all possible ADC values and discards
them except for the value IIO asked for. On the am335x-evm the driver
programs four values and it takes 500us to gather them. Reducing the number
of conversations down to the (required) one also reduces the busy loop down
to 125us.

This leads to another error, namely the FIFOCOUNT register is sometimes
(like one out of 10 attempts) not updated in time leading to EBUSY.
The next read has the FIFOCOUNT register updated.
Checking for the ADCSTAT register for being idle isn't a good choice either.
The problem is that if TSC is used at the same time, the HW completes the
conversation for ADC *and* before the driver noticed it, the HW begins to
perform a TSC conversation and so the driver never seen the HW idle. The
next time we would have two values in the FIFO but since the driver reads
everything we always see the current one.
So instead of polling for the IDLE bit in ADCStatus register, we should
check the FIFOCOUNT register. It should be one instead of zero because we
request one value.

This change in turn leads to another error. Sometimes if TSC & ADC are
used together the TSC starts generating interrupts even if nobody
actually touched the touchscreen. The interrupts seem valid because TSC's
FIFO is filled with values for each channel of the TSC. This condition stops
after a few ADC reads but will occur again. Not good.

On top of this (even without the changes I just mentioned) there is a ADC
& TSC lockup condition which was reported to me by Jeff Lance including the
following test case:
A busy loop of "cat /sys/bus/iio/devices/iio\:device0/in_voltage4_raw"
and a mug on touch screen. With this setup, the hardware will lockup after
something between 20 minutes and it could take up to a couple of hours.
During that lockup, the ADCSTAT register says 0x30 (or 0x70) which means
STEP_ID = IDLE and FSM_BUSY = yes. That means the hardware says that it is
idle and busy at the same time which is an invalid condition.

For all this reasons I decided to rework this TSC/ADC part and add a
handshake / synchronization here:
First the ADC signals that it needs the HW and writes a 0 mask into the
SE register. The HW (if active) will complete the current conversation
and become idle. The TSC driver will gather the values from the FIFO
(woken up by an interrupt) and won't "enable" another conversation.
Instead it will wake up the ADC driver which is already waiting. The ADC
driver will start "its" conversation and once it is done, it will
enable the TSC steps so the TSC will work again.

After this rework I haven't observed the lockup so far. Plus the busy
loop has been reduced from 500us to 125us.

The continues-read mode remains unchanged.
Signed-off-by: NSebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: NJonathan Cameron <jic23@kernel.org>
Signed-off-by: NLee Jones <lee.jones@linaro.org>

The update of the SE register in MFD doesn't look right as it has
nothing to do with it. The better place to do it is in TSC driver (which
is already doing it) and in the ADC driver which needs this only in the
continues mode.
Signed-off-by: NSebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: NJonathan Cameron <jic23@kernel.org>
Signed-off-by: NLee Jones <lee.jones@linaro.org>

The purpose of reg_se_cache has been defeated. It should avoid the
read-back of the register to avoid the latency and the fact that the
bits are reset to 0 after the individual conversation took place.

The reason why this is required like this to work, is that read-back of
the register removes the bits of the ADC so they do not start another
conversation after the register is re-written from the TSC side for the
update.
To avoid the not required read-back I introduce a "set once" variant which
does not update the cache mask. After the conversation completes, the
bit is removed from the SE register anyway and we don't plan a new
conversation "any time soon". The current set function is renamed to
set_cache to distinguish the two operations.
This is a small preparation for a larger sync-rework.
Signed-off-by: NSebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: NDmitry Torokhov <dmitry.torokhov@gmail.com>
Acked-by: NJonathan Cameron <jic23@kernel.org>
Signed-off-by: NLee Jones <lee.jones@linaro.org>

It somehow looks like the ending bracket belongs to the if statement but
it does belong to the while loop. This patch moves the bracket where it
belongs.
Signed-off-by: NSebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: NJonathan Cameron <jic23@kernel.org>
Signed-off-by: NLee Jones <lee.jones@linaro.org>

The driver is missing the iio_buffer_attach() call. As such it will attempt
to free the buffer twice on removal.

Introduced in commit 9e69c9 ("iio: Add reference counting for buffers").
Signed-off-by: NLars-Peter Clausen <lars@metafoo.de>
Reported-by: NSebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

ti_adc_dt_ids is always compiled in. Hence of_match_ptr is not
needed.
Signed-off-by: NSachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

The equivalent of iio_sw_buffer_preenable() is now done in the IIO buffer
core, so there is no need to do this from the driver anymore.
Signed-off-by: NLars-Peter Clausen <lars@metafoo.de>
Cc: Zubair Lutfullah <zubair.lutfullah@gmail.com>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

Driver is functional without this error case. Cleaned up.
Signed-off-by: NZubair Lutfullah <zubair.lutfullah@gmail.com>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

Trigger related headers and variables are not needed
as driver is now based on INDIO_BUFFER_HARDWARE mode
Signed-off-by: NZubair Lutfullah <zubair.lutfullah@gmail.com>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

Static is missing in function header. Corrected.
Signed-off-by: NZubair Lutfullah <zubair.lutfullah@gmail.com>
Reported-by: Nkbuild test robot <fengguang.wu@intel.com>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

Previously the driver had only one-shot reading functionality.
This patch adds continuous sampling support to the driver.

Continuous sampling starts when buffer is enabled.
HW IRQ wakes worker thread that pushes samples to userspace.
Sampling stops when buffer is disabled by userspace.

Patil Rachna (TI) laid the ground work for ADC HW register access.
Russ Dill (TI) fixed bugs in the driver relevant to FIFOs and IRQs.

I fixed channel scanning so multiple ADC channels can be read
simultaneously and pushed to userspace.
Restructured the driver to fit IIO ABI.
And added INDIO_BUFFER_HARDWARE mode.
Signed-off-by: NZubair Lutfullah <zubair.lutfullah@gmail.com>
Acked-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NRuss Dill <Russ.Dill@ti.com>
Acked-by: NLee Jones <lee.jones@linaro.org>
Acked-by: NSebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

12 bit ADC data is stored in 32 bits of storage.
Change from u32 to u16 to reduce wasted memory.
Signed-off-by: NZubair Lutfullah <zubair.lutfullah@gmail.com>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

Using devm_iio_device_alloc makes code simpler.
Signed-off-by: NSachin Kamat <sachin.kamat@linaro.org>
Cc: Rachna Patil <rachna@ti.com>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

Previously we tried to read data form ADC even before ADC sequencer
finished sampling. This led to wrong samples.
We now wait on ADC status register idle bit to be set.
Signed-off-by: NPatil, Rachna <rachna@ti.com>
Signed-off-by: NZubair Lutfullah <zubair.lutfullah@gmail.com>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

Add missing .driver_module of struct iio_info. This prevents the
module from being removed from underneath its users.
Signed-off-by: NWei Yongjun <yongjun_wei@trendmicro.com.cn>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

Usually we get all the values we wanted but it is possible, that te ADC
unit is busy performing the conversation for the HW events. In that case
-EBUSY is returned and the user may re-call the function.
Acked-by: NJonathan Cameron <jic23@kernel.org>
Signed-off-by: NSebastian Andrzej Siewior <bigeasy@linutronix.de>

The TSC part allows to specify the input lines. The IIO part assumes
that it usues always the last few, that means if IIO has adc-channels
set to 2 it will use channel 6 and 7. However it might make sense to use
only 6.
This patch changes the device property (which was introduced recently
and was never in an official release) in a way that the user can specify
which of the AIN lines should be used. In Addition to this, the name is
now AINx where x is the channel number i.e. for AIN6 we would have 6.
Prior this, it always started counting at 0 which is confusing. In
addition to this, it also checks for correct step number during reading
and does not rely on proper FIFO depth.
Acked-by: NJonathan Cameron <jic23@kernel.org>
Signed-off-by: NSebastian Andrzej Siewior <bigeasy@linutronix.de>

The driver programs a threshold of "coordinate_readouts" say 5. The
REG_FIFO0THR registers says it should it be programmed to "threshold
minus one". The driver does not expect just 5 coordinates but 5 * 2 + 2.
Multiplied by two because 5 for X and 5 for Y and plus 2 because we have
two Z.
The whole thing kind of works because It reads the 5 coordinates for X
and Y from FIFO0 and FIFO1 and the last element in each FIFO is ignored
within the loop and read later.
Nothing guaranties that FIFO1 is ready by the time it is read. In fact I
could see that that FIFO1 reaturns for Y channels 8,9, 10, 12, 6 and for
Y channel 7 for Z. The problem is that channel 7 and channel 12 got
somehow mixed up.
The other Problem is that FIFO1 is also used by the IIO part leading to
wrong results if both (tsc & adc) are used.

The patch tries to clean up the whole thing a little:
- Remove the +1 and -1 in REG_STEPCONFIG, REG_STEPDELAY and its counter
  part in the for loop. This is just confusing.

- Use only FIFO0 in TSC. The fifo has space for 64 entries so should be
  fine.

- Read the whole FIFO in one function and check the channel.

- in case we dawdle around, make sure we only read a multiple of our
  coordinate set. On the second interrupt we will cleanup the remaining
  enties.
Acked-by: NDmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: NSebastian Andrzej Siewior <bigeasy@linutronix.de>

TI-adc reads a little better compared to tiadc. And if we add am335x to
it then we have the same naming scheme as the tsc side.
Acked-by: NJonathan Cameron <jic23@kernel.org>
Signed-off-by: NSebastian Andrzej Siewior <bigeasy@linutronix.de>

This patch provides the members "datasheet_name" and scan_type. This is
the remaining part of the earlier patch where I (bigeasy) removed iio_map
because it is now supplied by the device tree. It also static names as
suggested by Jonathan.
Acked-by: NJonathan Cameron <jic23@kernel.org>
Signed-off-by: NPantelis Antoniou <panto@antoniou-consulting.com>
Signed-off-by: NFelipe Balbi <balbi@ti.com>
Signed-off-by: NSebastian Andrzej Siewior <bigeasy@linutronix.de>

This patch removes access to platform data mfd_tscadc_board because the
platform is DT only.
Acked-by: NJonathan Cameron <jic23@kernel.org>
Signed-off-by: NSebastian Andrzej Siewior <bigeasy@linutronix.de>

Add DT support for client ADC driver.
Acked-by: NJonathan Cameron <jic23@kernel.org>
Signed-off-by: NPatil, Rachna <rachna@ti.com>
Signed-off-by: NPantelis Antoniou <panto@antoniou-consulting.com>
Signed-off-by: NFelipe Balbi <balbi@ti.com>
Signed-off-by: NSebastian Andrzej Siewior <bigeasy@linutronix.de>

Current code has hard coded value written to
step enable bits. Now the bits are updated based
on how many steps are needed to be configured got
from platform data.

The user needs to take care not to exceed
the count more than 16. While using ADC and TSC
one should take care to set this parameter correctly.

Sebastian added the common lock and moved the code, that manipulates the
steps, from into the mfd module.
Signed-off-by: NPatil, Rachna <rachna@ti.com>
Signed-off-by: NFelipe Balbi <balbi@ti.com>
Signed-off-by: NSebastian Andrzej Siewior <bigeasy@linutronix.de>

The mfd driver creates platform data for the child devices and it is the
ti_tscadc_dev struct. This struct is copied for the two devices.
The copy of the structure makes a common lock in this structure a little
less usefull. Therefore the platform data is not a pointer to the
structure and the same structure is used.
While doing the change I noticed that the suspend/resume code assumes
the wrong pointer for ti_tscadc_dev and this has been fixed as well.
Signed-off-by: NSebastian Andrzej Siewior <bigeasy@linutronix.de>

The original info_mask is going away in favour of the broken out versions.
Signed-off-by: NJonathan Cameron <jic23@kernel.org>
cc: Patil, Rachna <rachna@ti.com>

CONFIG_HOTPLUG is going away as an option.  As a result, the __dev*
markings need to be removed.

This change removes the use of __devinit, __devexit_p, and __devexit
from these drivers.

Based on patches originally written by Bill Pemberton, but redone by me
in order to handle some of the coding style issues better, by hand.

Cc: Bill Pemberton <wfp5p@virginia.edu>
Cc: Jonathan Cameron <jic23@cam.ac.uk>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>