linux/drivers/staging/comedi
Ian Abbott 97c64322b8 staging: comedi: ni_tio: Allocate shadow regs for each counter chip
The "ni_tio" module contains code to allocate, destroy and operate on a
`struct ni_gpct_device`, which represents a number of counters spread
over one or more blocks (or "chips").  `struct ni_gpct_device` includes
an array member `regs` holding shadow copies of register values.
Unfortunately, this is currently shared by each block of counters so
they interfere with each other.  This is a problem for the "ni_660x"
module, which has 8 counters spread over 2 blocks.  The `regs` storage
needs to be two-dimensional, indexed by block (chip) number and register
number.  (It does not need to be three-dimensional because the registers
for individual counters are intermingled within the block.)

Change the `regs` member to an array pointer that can be indexed like a
two-dimensional array to access the shadow storage for each register in
each block.  Allocate the storage in `ni_gpct_device_construct()` and
free it in `ni_gpct_device_destroy()`.  (`ni_gpct_device_construct()`
can determine the number of blocks from the `num_counters` and
`counters_per_chip` parameters.)

Add new member `num_chips` to hold the number of chips.  Use that to
check that `chip_index` value is in range in the same places that
check the register offset is in range.

Remove the `counters_per_chip` member of `struct ni_gpct_device` as it
is not needed anywhere and could be easily derived from the
`num_counters` and `num_chips` members if required.

Thanks to GitHub user "raabej" (real name unknown) for an initial
implementation of this in the out-of-tree fork of the Comedi drivers.

Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-02-26 11:50:17 +01:00
..
drivers staging: comedi: ni_tio: Allocate shadow regs for each counter chip 2019-02-26 11:50:17 +01:00
kcomedilib
comedi_buf.c
comedi_compat32.c Remove 'type' argument from access_ok() function 2019-01-03 18:57:57 -08:00
comedi_compat32.h Staging: comedi: comedi_compat32.h: fixed missing or malformed SPDX-License-Identifier 2018-06-18 10:55:11 +02:00
comedi_fops.c staging: comedi: comedi_fops.c: Remove redundant blank line 2019-02-04 12:30:27 +01:00
comedi_internal.h
comedi_pci.c
comedi_pci.h Staging: comedi: comedi_pci.h: fixed missing or malformed SPDX-License-Identifier 2018-06-18 10:55:11 +02:00
comedi_pcmcia.c
comedi_pcmcia.h Staging: comedi: comedi_pcmcia.h: fixed missing or malformed SPDX-License-Identifier 2018-06-18 10:55:11 +02:00
comedi_usb.c
comedi_usb.h staging: comedi: comedi_usb.h: SPDX License Identifier is added in the first line 2018-05-31 19:00:53 +02:00
comedi.h staging: comedi: clarify/unify macros for NI macro-defined terminals 2018-11-07 13:08:28 +01:00
comedidev.h staging: comedi: add new device-global config interface 2018-10-09 15:32:38 +02:00
comedilib.h Staging: comedi: comedilib.h: fixed missing or malformed SPDX-License-Identifier 2018-06-18 10:55:11 +02:00
drivers.c staging: comedi: add new device-global config interface 2018-10-09 15:32:38 +02:00
Kconfig staging: comedi: add interface to ni routing table information 2018-10-09 15:36:04 +02:00
Makefile
proc.c proc: introduce proc_create_single{,_data} 2018-05-16 07:23:35 +02:00
range.c
TODO