On Sat, Oct 12, 2019 at 03:00:12PM +0100, Jonathan Cameron wrote: > Hi William > > What's the status on these? If you are happy that reviews and > testing is complete enough, do you want me to take them after > I pick up the eqep driver (hopefully shortly dependent on > the pull request Greg has from me being fine). > > Thanks, > > Jonathan Yes, this is ready for you to take. So after the eqep driver is picked up you can apply this patchset. Thanks, William Breathitt Gray > > On Sun, 6 Oct 2019 16:03:08 -0400 > William Breathitt Gray <vilhelm.gray@xxxxxxxxx> wrote: > > > Changes in v5: > > - Add changes and additions to generic-counter.rst to clarify theory > > and use of the Generic Counter interface > > - Fix typo in counter.h action_get description comment > > > > The changes in this patchset will not affect the userspace interface. > > Rather, these changes are intended to simplify the kernelspace Counter > > callbacks for counter device driver authors. > > > > The following main changes are proposed: > > > > * Retire the opaque counter_count_read_value/counter_count_write_value > > structures and simply represent count data as an unsigned integer. > > > > * Retire the opaque counter_signal_read_value structure and represent > > Signal data as a counter_signal_value enum. > > > > These changes should reduce some complexity and code in the use and > > implementation of the count_read, count_write, and signal_read > > callbacks. > > > > The opaque structures for Count data and Signal data were introduced > > originally in anticipation of supporting various representations of > > counter data (e.g. arbitrary-precision tallies, floating-point spherical > > coordinate positions, etc). However, with the counter device drivers > > that have appeared, it's become apparent that utilizing opaque > > structures in kernelspace is not the best approach to take. > > > > I believe it is best to let userspace applications decide how to > > interpret the count data they receive. There are a couple of reasons why > > it would be good to do so: > > > > * Users use their devices in unexpected ways. > > > > For example, a quadrature encoder counter device is typically used to > > keep track of the position of a motor, but a user could set the device > > in a pulse-direction mode and instead use it to count sporadic rising > > edges from an arbitrary signal line unrelated to positioning. Users > > should have the freedom to decide what their data represents. > > > > * Most counter devices represent data as unsigned integers anyway. > > > > For example, whether the device is a tally counter or position > > counter, the count data is represented to the user as an unsigned > > integer value. So specifying that one device is representing tallies > > while the other specifies positions does not provide much utility from > > an interface perspective. > > > > For these reasons, the count_read and count_write callbacks have been > > redefined to pass count data directly as unsigned long instead of passed > > via opaque structures: > > > > count_read(struct counter_device *counter, > > struct counter_count *count, unsigned long *val); > > count_write(struct counter_device *counter, > > struct counter_count *count, unsigned long val); > > > > Similarly, the signal_read is redefined to pass Signal data directly as > > a counter_signal_value enum instead of via an opaque structure: > > > > signal_read(struct counter_device *counter, > > struct counter_signal *signal, > > enum counter_signal_value *val); > > > > The counter_signal_value enum is simply the counter_signal_level enum > > redefined to remove the references to the Signal data "level" data type. > > > > William Breathitt Gray (3): > > counter: Simplify the count_read and count_write callbacks > > docs: driver-api: generic-counter: Update Count and Signal data types > > counter: Fix typo in action_get description > > > > Documentation/driver-api/generic-counter.rst | 162 +++++++++++-------- > > drivers/counter/104-quad-8.c | 33 ++-- > > drivers/counter/counter.c | 101 ++---------- > > drivers/counter/ftm-quaddec.c | 14 +- > > drivers/counter/stm32-lptimer-cnt.c | 5 +- > > drivers/counter/stm32-timer-cnt.c | 17 +- > > drivers/counter/ti-eqep.c | 19 +-- > > include/linux/counter.h | 76 ++------- > > 8 files changed, 144 insertions(+), 283 deletions(-) > > > > > > base-commit: 0c3aa63a842d84990bd02622f2fa50d2bd33c652 > > prerequisite-patch-id: ebe284609b3db8d4130ea2915f7f7b185c743a70 > > prerequisite-patch-id: cbe857759f10d875690df125d18bc04f585ac7c9 > > prerequisite-patch-id: 21f2660dc88627387ee4666d08044c63dd961dae >
