| Message ID | cover.1570391994.git.vilhelm.gray@gmail.com (mailing list archive) |
|---|---|
| Headers | show |
| Series | Simplify count_read/count_write/signal_read | expand |
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 On Sun, 6 Oct 2019 16:03:08 -0400 William Breathitt Gray <vilhelm.gray@gmail.com> 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
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@gmail.com> 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 >
On Sat, 12 Oct 2019 10:51:19 -0400 William Breathitt Gray <vilhelm.gray@gmail.com> wrote: > 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. Series applied to the togreg branch of iio.git and pushed out as testing for the autobuilders to play with it. Thanks, Jonathan > > Thanks, > > William Breathitt Gray > > > > > On Sun, 6 Oct 2019 16:03:08 -0400 > > William Breathitt Gray <vilhelm.gray@gmail.com> 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 > >
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