Implement COMEDI asynchronous commands on the fake analog output
subdevice.  This is useful for testing asynchronous commands in the
"write" direction when no real hardware is available.

A normal kernel timer is used to drive the command.  The new timer
expiry function `waveform_ao_timer()` handles whole "scans" at a time
according to the number of scan period that have elapsed since the last
scan.  Data for each channel in the scan is written to the internal
loopback array `devpriv->ao_loopbacks[]` and can be read back on the
analog input channels.  However, if several scan periods are outstanding
in the timer expiry function, only the latest available scan data is
written to the loopback array in order to save processing time.  The
expiry function also checks for underrun conditions, and checks for
normal termination of the asynchronous command when a "stop" scan count
is reached.

After the command is tested by `waveform_ao_cmdtest()` and set up by
`waveform_ao_cmd()`, it is not started until an internal trigger
function `waveform_ao_inttrig_start()` is called as a result of the user
performing an `INSN_INTTRIG` instruction on the subdevice.  The command
is stopped when the "cancel" handler `waveform_ao_cancel()` is called.
This may be due to the command terminating due to completion or an
error, or as a result of the user cancelling the command.
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Reviewed-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

`waveform_ai_interrupt()` is a timer expiry function used to generate
fake waveform data for an analog input subdevice.  Rename it to
`waveform_ai_timer()`.
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Reviewed-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

For asynchronous command handling on the analog input subdevice, a
kernel timer routine is used to generate the fake waveform data.  A
"scan" consists of a number of conversions separated in time by a
conversion period.  Successive scans are separated in time by a scan
period, which is at least the conversion period multiplied by the number
of conversions per scan.  Currently, the timer routine does not generate
any data until the end of a scan period, generating whole scans of data
at a time.  Change it to generate data at the end of each conversion
period, with an extra delay after the final conversion in each scan if
necessary.  Use new member `ai_convert_time` in the private data
structure `struct waveform_private` to keep track of when the next
conversion is due.  This replaces the old member `ai_last_scan_time`
which kept track of the time of the previous scan.
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Reviewed-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

COMEDI drivers often allow the last value written to a channel on an
analog output subdevice to be read back via the "insn_read" handler.
The "comedi_test" driver does not currently support that.  It is a bit
special because it loops back the last values written to the channel on
the analog output subdevice to be read back via corresponding channels
on the analog input subdevice.  The "insn_read" handler for the analog
input subdevice is `waveform_ai_insn_read()`.  Set that as the
"insn_read" handler for the analog output subdevice as well.
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Reviewed-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

The last sample values written to the AO subdevice channels by its
"insn_write" handler `waveform_ao_insn_write()` are stored in the member
array `ao_loopbacks[]` in the device private data `struct
waveform_private`.  They can be read back via the "insn_read" handler of
the AI subdevice `waveform_ai_insn_read()`.  As the stored sample values
are only 16 bits wide, change the type of the `ao_loopbacks[]` member to
`unsigned short` to save some space.
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Reviewed-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

The asynchronous command handling for the analog input subdevice uses a
kernel timer which expires approximately `HZ` times a second.  However,
it only needs to do anything after each scan period.  Set the timer to
expire just after the next scan period.

Although the timer expiry function `waveform_ai_interrupt()` uses
precise time values to generate the fake waveforms used to generate the
data, those time values are constructed in a precise sequence, and do
not depend on the time the timer expiry function is actually called.  So
the timer expiry rate does not have to be very precise.
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Reviewed-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Rename the members `struct waveform_private` associated with fake
waveform generation.  The affected members are `uvolt_amplitude` -->
`wf_amplitude` (the amplitude of the waveform), `usec_period` -->
`wf_period` (the period of the waveform), and `usec_current` -->
`wf_current` (the current time within a waveform period).
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Reviewed-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Rename the members of `struct waveform_private` that are used to handle
AI commands, apart from those members used to control fake waveform
generation.  The renames are `timer` --> `ai_timer`, `scan_period` -->
`ai_scan_period`, and `convert_period` --> `ai_convert_period`.
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Reviewed-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

The private data structure `struct waveform_private` currently uses
member `last` to remember the time of the last timer interrupt, and the
member `usec_remainder` to keep track of how far into a simulated scan
the interrupt occurred.  Replace these with a single new member
`ai_last_scan_time` that records the time of the last scan.  This
simplifies the calculation of the number of scans to simulate in the
timer routine, `waveform_ai_interrupt()`.
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Reviewed-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Use `unsigned int` instead of `unsigned long` to hold the period of the
fake waveform generator and the current time within each waveform.  The
waveform period will be no more than `INT_MAX` and the current time
within the waveform (prior to the modulo operation to bring it actually
within the waveform period) will be no more than `INT_MAX + UINT_MAX /
1000`.
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Reviewed-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

The fake waveform generator functions, `fake_sawtooth()` and
`fake_squarewave()`, called from `fake_waveform()`, have a
`current_time` parameter which is the time since the start of a waveform
period.  The parameter value may be greater than the waveform period so
they do a modulo operation to bring it into range.  Do the modulo
operations outside the functions in `waveform_ai_interrupt()` so that
the waveform generator functions always get a `current_time` parameter
less than the waveform period and do not have to do the modulo operation
themselves.  Also, only do the modulo operations when the time since the
start of a waveform exceeds the waveform period.  Usually, several
samples are produced in each waveform period and modulo operations are
typically more expensive than a simple comparison.
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Reviewed-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

It is quite common for COMEDI subdevices that support commands to
support setting `scan_begin_src` to `TRIG_FOLLOW`.  This means the next
scan begins once all conversions in the current scan are complete.
Support the following timing combinations for the AI subdevice:

  scan_begin_src == TRIG_TIMER && convert_src == TRIG_TIMER
  scan_begin_src == TRIG_TIMER && convert_src == TRIG_NOW
  scan_begin_src == TRIG_FOLLOW && convert_src == TRIG_TIMER

The actual scan period in microseconds is stored in the `scan_period`
member of the private data structure `struct waveform_private`.  An
`unsigned int` is still wide enough, because the conversion period is no
more than `UINT_MAX / 1000` microseconds and the number of conversions
is no more than 16 (`N_CHANS * 2`).
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Reviewed-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

When testing the parameters for setting up an asynchronous command on
the AI subdevice, limit the maximum conversion period
(`cmd->convert_arg`) so that the number of conversions in a scan
(`cmd->scan_end_arg`, same as `cmd->chanlist_len`) multiplied by the
conversion period fits within an `unsigned int`, as that is used to
limit the minimum scan period (`cmd->scan_begin_arg`).

Also ensure rounding of the conversion period and scan period to the
nearest microsecond both fit in an `unsigned int`.  Do all this in stage
4 ("fix up any arguments") of the command testing.
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Reviewed-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

The `static const int nano_per_micro` variable is set to 1000, the
number of nanoseconds in a microsecond.  Remove it and use the
`NSEC_PER_USEC` macro from <linux/time.h> instead.
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Reviewed-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

While an asynchronous command is running on the analog input subdevice,
fake waveform generators are connected to each channel to provide the
input voltages that are converted to sample value.  Channel 0 is
connected to a sawtooth generator, channel 1 is connected to a
squarewave generator, and the remaining channels are connected to a
flatline generator.  The non-flatline generators share the same
amplitude (in microvolts) and period (in microseconds) which are
configured when the COMEDI device is attached.  All waveforms are
centered around 0 microvolts and the non-flatline waveforms go between
-amplitude and +amplitude.

It is possible for the waveforms to swing outside the input range of the
channels to which they are connected.  When that happens, the sample
values resulting from simulated A-to-D conversion will wrap around due
to integer overflow.  Prevent that by clamping the sample values that
would go out of range.  This is closer to how a real hardware device
would behave (assuming the input voltage is not high enough to damage
the hardware!).
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Reviewed-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Use the preferred style for multi-line comments.
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Reviewed-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

This patch removes the unnecessary wait_queue that has exclusively been
used for the poll function and its poll_table. Instead, an already
existing one is used.
Signed-off-by: Christian Gromm <christian.gromm@microchip.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

This patch replaces the usage of min() by min_t().
Signed-off-by: Christian Gromm <christian.gromm@microchip.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

This patch adds brackets on all of the conditional branches in
order to follow the linux coding style.
Signed-off-by: Ioana Ciornei <ciorneiioana@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

This patch moves the logical operators on the previous line in order
to follow the linux coding style.
Signed-off-by: Ioana Ciornei <ciorneiioana@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

This patch removes unwanted blank lines in order to follow
the linux coding style.
Signed-off-by: Ioana Ciornei <ciorneiioana@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

This patch properly aligns the block comment in order
to follow the linux coding style convetions.
Signed-off-by: Ioana Ciornei <ciorneiioana@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

This patch add blank lines after functions definitions in
order to follow the linux coding style.
Signed-off-by: Ioana Ciornei <ciorneiioana@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

This patch changes uint8_t type to preferred kernel
type u8 in order to follow the linux coding style
conventions.
Signed-off-by: Ioana Ciornei <ciorneiioana@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

This patch properly aligns the function arguments or
its parameters in order to match the open bracket.
Signed-off-by: Ioana Ciornei <ciorneiioana@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

This patch adds spaces around binary operators such as '*',
'/', '+' in order to improve readability.
Signed-off-by: Ioana Ciornei <ciorneiioana@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

This patch is to the host_interface.c that fixes up following
warning by checkpatch:

-prefer eth_broadcast_addr() over memset()
Signed-off-by: Punit Vara <punitvara@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

This patch fixes line over 80 characters found by checkpatch.

WARNING: line over 80 characters
FILE: drivers/staging/wilc1000/host_interface.h:424:
Signed-off-by: Chaehyun Lim <chaehyun.lim@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

This patch replaces kmalloc followed by memcpy with kmemdup.
It is also added error checking to return -ENOMEM when kmemdup is
failed.
Signed-off-by: Chaehyun Lim <chaehyun.lim@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

This patch changes tenuAuth_type to auth_type that is sixth argument of
this function to avoid camelcase.
Signed-off-by: Chaehyun Lim <chaehyun.lim@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

This patch changes u8mode to mode that is fifth argument of this
function to avoid camelcase.
Signed-off-by: Chaehyun Lim <chaehyun.lim@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

This patch changes u8Keyidx to index that is fourth argument of this
function to avoid camelcase.
Signed-off-by: Chaehyun Lim <chaehyun.lim@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

This patch changes u8WepKeylen to len that is third argument of this
function to avoid camelcase.
Signed-off-by: Chaehyun Lim <chaehyun.lim@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

This patch changes pu8WepKey to key that is second argument of this
function to avoid camelcase.
Signed-off-by: Chaehyun Lim <chaehyun.lim@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

This patch changes data type of variable i from u8 to int.
It is used as index of an array to print its content. It's better
to use as data type of int.
Signed-off-by: Chaehyun Lim <chaehyun.lim@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

This patch changes struct host_if_drv of host_int_add_wep_key_bss_ap
function declaration from hWFIDrv to hif_drv.
With this change, first parameter name of this function declaration and
definition has same name as hif_drv.
Signed-off-by: Chaehyun Lim <chaehyun.lim@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

This patch changes return type of host_int_add_wep_key_bss_ap from s32
to int. The result variable gets return value from wilc_mq_send that has
return type of int. It should be changed return type of this function as
well as data type of result variable.
Signed-off-by: Chaehyun Lim <chaehyun.lim@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

This patch fixes line over 80 characters found by checkpatch.

WARNING: line over 80 characters
FILE: drivers/staging/wilc1000/host_interface.h:408:
Signed-off-by: Chaehyun Lim <chaehyun.lim@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

This patch replaces kmalloc followed by memcpy with kmemdup.
It is also added error checking of kmemdup.
Signed-off-by: Chaehyun Lim <chaehyun.lim@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

This patch changes u8Keyidx to index that is fourth argument of
host_int_add_wep_key_bss_sta to avoid camelcase.
Signed-off-by: Chaehyun Lim <chaehyun.lim@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>