Tidy up the multi line comments to follow the CodingStyle.

Remove the multi line comment about an alternate driver for the
PCL-711. The http address does not work and the driver history
in the comment is unnecessary.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Rename some of the register map defines so they all have the same
format. Add a couple new defines to tidy up some of the magic
numbers used with the registers.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

The comedi core always calls the (*do_cmdtest) function to validate
a command before it calls the (*do_cmd) function.

Since the (*do_cmdtest) has already calculated the timer values in
order to validate the cmd->scan_begin_arg there is no reason to
recalc the values in the (*do_cmd).

This also fixes a bug in the driver. The (*do_cmdtest) was using a
time base value of 100 and but the (*do_cmd) was using a time base
of 500. These result in different timer values. The functions used
to calculate the values are actually the same due to a #define in
the 8253.h header.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

This static const int variable is only used one place in the code.
Remove it and just open code the value.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

To better document the code, use the i8254_load() helper to set the
timers instead of doing the outb() instructions.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Remove all the private data variables that are not used by the driver.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

This member in the board info is used to indicate if the board is
a PCL711B. This board uses bits in the mode register to select the
IRQ used for interrupts. These bits do nothing on the other boards
supported by this driver.

Remove the 'is_pcl711b' variable from the boardinfo. Also, remove
the 'mode' variable from the private data and just calculate the
mode bits when needed.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

This member in the boardinfo is redundant. All the 8112 style boards
have > 8 analog input channels (16 actually). We can use that information
instead and remove the extra boardinfo.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

For aesthetic reasons, rename this function to help with greps.

Tidy up the function a bit to follow the comedi driver norm.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

The acl-8112 boards also need to write a value to the software
trigger register in order to start an A/D conversion. Remove the
if (!board->is_8112) test so that the write is always done.

Also, the analog input mode does not need to be set each time for
multiple samples. Move the pcl711_ai_set_mode() out of the for loop.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

At the end of an asynchronous command, the analog input is returned
to software triggered mode. For the non-8112 style boards the mode
PCL711_MODE_DEFAULT and PCL711_MODE_SOFTTRIG are identical. Just set
the mode to PCL711_MODE_SOFTTRIG and remove the test.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Define the magic numbers used with the mode register.

For the PCL711B board, the mode register also contains the irq number
that is being used. Introduce a helper function to write to the mode
register so that this irq number is always included when needed.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

The ACL-8112 boards can do differential analog inputs. Add support for
this mode.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Currently the board->is_8112 handling in this function does not write
the value to the mux register. Also, the value for channels >= 8 is
calculated incorrectly.

Define the magic numbers used with the mux register and fix the function
so 8112 boards work correctly.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Factor out the analog input end-of-conversion wait to clarify the
pcl711_ai_insn() function a bit.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

The comedi_subdevice used in the interrupt handler is the dev->read_subdev
that was initialized during the attach of the board. Use that instead of
accessing the dev->subdevices array directly.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Introduce a helper function to read the analog input data from the
hardware.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Tidy up this function to follow the normal form in comedi drivers.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

For aesthetics, rename this function to help with greps.

Introduce a helper function to write the values to the analog
output channel registers. Modify the defines for the D/A registers
to avoid the ? : tests based on the chan number.

Only the final value written needs to be saved for read back.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Add some whitespace to the register map defines to make the code
easier to read.

For aesthetics, convert all the values to hex. This is more common
in comedi drivers.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Move the storing of the irq in the mode register for the pcl711b board
so it's only done when the irq is actually used by the driver.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

For aesthetic reasons, add some whitespace to the subdevice init.

The 's->len_chanlist' is only used with asynchronous command support.
Remove the unnecessary initialization of this member in the subdevices
that do not support commands. For the analog input subdevice, move
the initialization so it only occurs when commands are supported.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

This define is only used in the comedi_request_region() call. It doesn't
really add any clarity to the code so remove it and just open code the
value.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Interrupts are only needed to support asynchronous commands with the
analog input subdevice. Since the interrupt is optional during the
attach of the board, don't fail the attach if it's not available.

Also, remove the printk() noise about the irq. The user will know if
the interrupt is available due to the subdev_flag SDF_CMD_READ being
set for the analog input subdevice.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

For aesthetic reasons, cleanup the whitespace in the comedi_lrange
tables.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

To save a bit of space, convert the 'is_pcl711b' and 'is_8112' flags
in the boardinfo to bit-fields.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

The 'is_dg' and 'n_ranges' members in the boardinfo are not used by
the driver. Remove them.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Remove all the '= 0' entries in the boardinfo. They will default to 0.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Convert the boardinfo declaration to C99 format to make it less error
prone and easier to maintain.

For aesthetics, move the declaration closer to the struct definition.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Change the MODULE_DESCRIPTION to something useful instead of the
generic "Comedi low-level driver".
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Tidy up the multi-line comments to follow the CodingStyle.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Remove the final dev_info() at the end of the board attach. This is
just added noise.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

For aesthetics, rename this function to help with greps,

Change the type of 'chan' to match the type of the insn->chanspec
that it is derived from using the CR_CHAN macro.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

For aesthetics, rename this function to help with greps,

Change the type of 'chan' to match the type of the insn->chanspec
that it is derived from using the CR_CHAN macro.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Use comedi_offset_munge() to munge the offset binary values from the
comedi core into the two's complement form that the hardware expects.

This removes the hard coded assumption that the analog outputs are
16-bits and instead does the munging based on the s->maxdata.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

The comedi core expects the data to/from analog subdevices to be
in offset binary coding. This means that a value of '0' represents
the most negative and a value of 's->maxdata' the most positive
signal of the analog subdevice.

Many comedi drivers require the data written to the analog outputs,
or returned from the analog inputs, be in two's complement format.

Introduce a helper function to munge the data for analog subdevices.
This function simply inverts the sign bit and masks the result by
's->maxdata' to keep the result in range for the subdevice. The
strange:

  return val ^ s->maxdata ^ (s->maxdata >> 1);

is equivalent to:

  return (val ^ ((s->maxdata + 1) >> 1) & s->maxdata;

as long as s->maxdata is a value of the form (1 << n) - 1. This
avoids the 32-bit unsigned overflow for a s->maxdata of 0xffffffff.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Remove a possible deadlock while waiting to write the analog output data.

The data transfer rate for every D/A data write in this driver is 2.2us.
Wait up to 10us for the board to be ready then and return -ETIME.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

This driver munges the raw data from the comedi core into its two's
complement form before writing it to the hardware. The last value
written to the hardware is saved in the private data for readback.

Since the comedi core always expects the data to be in offset binary
coding, make sure to save the un-munged value for readback.

Also, prefetch the current readback value before attempting to update
the hardware. This ensures that the readback value is correct if no
values are actually written.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

This resolves the merge problem with two iio drivers that Stephen
Rothwell pointed out.
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>