| Message ID | cover.1613131238.git.vilhelm.gray@gmail.com (mailing list archive) |
|---|---|
| Headers | show |
| Series | Introduce the Counter character device interface | expand |
On Fri, 12 Feb 2021 21:13:37 +0900 William Breathitt Gray <vilhelm.gray@gmail.com> wrote: > This is a reimplementation of the Generic Counter driver interface. > There are no modifications to the Counter subsystem userspace interface, > so existing userspace applications should continue to run seamlessly. > > The purpose of this patch is to internalize the sysfs interface code > among the various counter drivers into a shared module. Counter drivers > pass and take data natively (i.e. u8, u64, etc.) and the shared counter > module handles the translation between the sysfs interface and the > device drivers. This guarantees a standard userspace interface for all > counter drivers, and helps generalize the Generic Counter driver ABI in > order to support the Generic Counter chrdev interface (introduced in a > subsequent patch) without significant changes to the existing counter > drivers. > > Note, Counter device registration is the same as before: drivers > populate a struct counter_device with components and callbacks, then > pass the structure to the devm_counter_register function. However, > what's different now is how the Counter subsystem code handles this > registration internally. > > Whereas before callbacks would interact directly with sysfs data, this > interaction is now abstracted and instead callbacks interact with native > C data types. The counter_comp structure forms the basis for Counter > extensions. > > The counter-sysfs.c file contains the code to parse through the > counter_device structure and register the requested components and > extensions. Attributes are created and populated based on type, with > respective translation functions to handle the mapping between sysfs and > the counter driver callbacks. > > The translation performed for each attribute is straightforward: the > attribute type and data is parsed from the counter_attribute structure, > the respective counter driver read/write callback is called, and sysfs > I/O is handled before or after the driver read/write function is called. > > Cc: Syed Nayyar Waris <syednwaris@gmail.com> > Cc: Patrick Havelange <patrick.havelange@essensium.com> > Cc: Kamel Bouhara <kamel.bouhara@bootlin.com> > Cc: Fabrice Gasnier <fabrice.gasnier@st.com> > Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com> > Cc: Alexandre Torgue <alexandre.torgue@st.com> > Cc: David Lechner <david@lechnology.com> > Cc: Dan Carpenter <dan.carpenter@oracle.com> > Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com> A few minor comments inline. This set is still huge, so I've only looked at the core code for this version. Hopefully driver maintainers will do the thorough review of how it effects the individual drivers! Jonathan > --- > MAINTAINERS | 1 - > drivers/counter/104-quad-8.c | 449 +++---- > drivers/counter/Makefile | 1 + > drivers/counter/counter-core.c | 153 +++ > drivers/counter/counter-sysfs.c | 833 +++++++++++++ > drivers/counter/counter-sysfs.h | 13 + > drivers/counter/counter.c | 1496 ----------------------- > drivers/counter/ftm-quaddec.c | 56 +- > drivers/counter/microchip-tcb-capture.c | 87 +- > drivers/counter/stm32-lptimer-cnt.c | 164 ++- > drivers/counter/stm32-timer-cnt.c | 142 +-- > drivers/counter/ti-eqep.c | 211 ++-- > include/linux/counter.h | 631 +++++----- > include/linux/counter_enum.h | 45 - > 14 files changed, 1816 insertions(+), 2466 deletions(-) > create mode 100644 drivers/counter/counter-core.c > create mode 100644 drivers/counter/counter-sysfs.c > create mode 100644 drivers/counter/counter-sysfs.h > delete mode 100644 drivers/counter/counter.c > delete mode 100644 include/linux/counter_enum.h > > diff --git a/MAINTAINERS b/MAINTAINERS > index d858582c917b..94a19606d947 100644 > --- a/MAINTAINERS > +++ b/MAINTAINERS > @@ -4543,7 +4543,6 @@ F: Documentation/ABI/testing/sysfs-bus-counter > F: Documentation/driver-api/generic-counter.rst > F: drivers/counter/ > F: include/linux/counter.h > -F: include/linux/counter_enum.h > > CPMAC ETHERNET DRIVER > M: Florian Fainelli <f.fainelli@gmail.com> > diff --git a/drivers/counter/104-quad-8.c b/drivers/counter/104-quad-8.c > index eca3f6482719..41fdbd228be3 100644 > --- a/drivers/counter/104-quad-8.c > +++ b/drivers/counter/104-quad-8.c > @@ -116,7 +116,7 @@ static int quad8_signal_read(struct counter_device *counter, ... > diff --git a/drivers/counter/counter-sysfs.c b/drivers/counter/counter-sysfs.c > new file mode 100644 > index 000000000000..52513a213cc5 > --- /dev/null > +++ b/drivers/counter/counter-sysfs.c > @@ -0,0 +1,833 @@ ... > + > +static ssize_t counter_comp_u8_show(struct device *dev, > + struct device_attribute *attr, char *buf) > +{ > + const struct counter_attribute *const a = to_counter_attribute(attr); > + struct counter_device *const counter = dev_get_drvdata(dev); > + int err; > + u8 data = 0; > + > + switch (a->scope) { > + case COUNTER_SCOPE_DEVICE: > + err = a->comp.device_u8_read(counter, &data); > + break; > + case COUNTER_SCOPE_SIGNAL: > + err = a->comp.signal_u8_read(counter, a->parent, &data); > + break; > + case COUNTER_SCOPE_COUNT: > + err = a->comp.count_u8_read(counter, a->parent, &data); > + break; I'd add a default in here just to make it obvious anything else is an error. Same in other similar cases that follow. > + } > + if (err < 0) > + return err; > + > + if (a->comp.type == COUNTER_COMP_BOOL) > + data = !!data; > + > + return sprintf(buf, "%u\n", (unsigned int)data); > +} > + ... > + > +static int counter_name_attr_create(struct device *const dev, > + struct counter_attribute_group *const group, > + const char *const name) > +{ > + struct counter_attribute *counter_attr; > + > + /* Allocate Counter attribute */ > + counter_attr = devm_kzalloc(dev, sizeof(*counter_attr), GFP_KERNEL); > + if (!counter_attr) > + return -ENOMEM; > + > + /* Configure Counter attribute */ > + counter_attr->comp.name = name; > + > + /* Configure device attribute */ > + sysfs_attr_init(&counter_attr->dev_attr.attr); > + counter_attr->dev_attr.attr.name = "name"; > + counter_attr->dev_attr.attr.mode = 0444; > + counter_attr->dev_attr.show = counter_comp_name_show; > + > + /* Store list node */ > + list_add(&counter_attr->l, &group->attr_list); > + group->num_attr++; > + > + return 0; > +} Trivial but one too many blank lines. > + > + > +static struct counter_comp counter_signal_comp = { > + .type = COUNTER_COMP_SIGNAL_LEVEL, > + .name = "signal", > +}; ... > static struct counter_synapse ti_eqep_position_synapses[] = { > diff --git a/include/linux/counter.h b/include/linux/counter.h > index d16ce2819b48..76b0b06dd5db 100644 > --- a/include/linux/counter.h > +++ b/include/linux/counter.h > @@ -6,42 +6,184 @@ > #ifndef _COUNTER_H_ > #define _COUNTER_H_ > ...
On 2/12/21 6:13 AM, William Breathitt Gray wrote: > This is a reimplementation of the Generic Counter driver interface. > There are no modifications to the Counter subsystem userspace interface, > so existing userspace applications should continue to run seamlessly. > > The purpose of this patch is to internalize the sysfs interface code > among the various counter drivers into a shared module. Counter drivers > pass and take data natively (i.e. u8, u64, etc.) and the shared counter > module handles the translation between the sysfs interface and the > device drivers. This guarantees a standard userspace interface for all > counter drivers, and helps generalize the Generic Counter driver ABI in > order to support the Generic Counter chrdev interface (introduced in a > subsequent patch) without significant changes to the existing counter > drivers. > > Note, Counter device registration is the same as before: drivers > populate a struct counter_device with components and callbacks, then > pass the structure to the devm_counter_register function. However, > what's different now is how the Counter subsystem code handles this > registration internally. > > Whereas before callbacks would interact directly with sysfs data, this > interaction is now abstracted and instead callbacks interact with native > C data types. The counter_comp structure forms the basis for Counter > extensions. > > The counter-sysfs.c file contains the code to parse through the > counter_device structure and register the requested components and > extensions. Attributes are created and populated based on type, with > respective translation functions to handle the mapping between sysfs and > the counter driver callbacks. > > The translation performed for each attribute is straightforward: the > attribute type and data is parsed from the counter_attribute structure, > the respective counter driver read/write callback is called, and sysfs > I/O is handled before or after the driver read/write function is called. > > Cc: Syed Nayyar Waris <syednwaris@gmail.com> > Cc: Patrick Havelange <patrick.havelange@essensium.com> > Cc: Kamel Bouhara <kamel.bouhara@bootlin.com> > Cc: Fabrice Gasnier <fabrice.gasnier@st.com> > Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com> > Cc: Alexandre Torgue <alexandre.torgue@st.com> > Cc: David Lechner <david@lechnology.com> > Cc: Dan Carpenter <dan.carpenter@oracle.com> > Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com> > --- For TI eQEP bits... Reviewed-by: David Lechner <david@lechnology.com> Tested-by: David Lechner <david@lechnology.com>
Changes in v8: - Consolidated Counter sysfs ABI documentation to single file - Added events_queue_size sysfs attribute to allow users to dynamically resize the events queue - Fixed markup syntax and typos in generic-counter.rst - Improved documentation in include/uapi/linux/counter.h and friends - Renamed COUNTER_LOAD_WATCHES_IOCTL to COUNTER_ENABLE_EVENTS_IOCTL; Renamed COUNTER_CLEAR_WATCHES_IOCTL to COUNTER_DISABLE_EVENTS_IOCTL - Renamed the struct counter_event "errno" member to "status" - Dropped the "irq_trigger" 104-QUAD-8 sysfs attribute; this functionality now occurs implicitly via the Counter chrdev interface - Return -ERANGE where appropriate instead of -EINVAL - Simplified switch exit paths; return early when possible - Call devm_request_irq() before devm_counter_register() for 104-quad-8 - Renamed devm_counter_unregister() to more apt devm_counter_release() - Use enum counter_scope for scope values in counter-sysfs.c - Use sysfs_emit() instead of sprintf() where appropriate - Renamed find_in_string_array() to more apt counter_find_enum() - Renamed *_action_get() and *_action_write() to *_action_read() and *_action_write() to match new naming convention of Counter callbacks - Use "Counter function" naming convention instead of "Counter count function" to avoid confusion about scope I pulled out a lot of bits and pieces to their own patches; hopefully that makes reviewing this patchset much simpler than before. This patchset is also available on my personal public git repo for anyone who wants a quick way to clone: https://gitlab.com/vilhelmgray/iio/-/tree/counter_chrdev_v8 The patches preceding "counter: Internalize sysfs interface code" are primarily cleanup and fixes that can be picked up and applied now to the IIO tree if so desired. The "counter: Internalize sysfs interface code" patch as well may be considered for pickup because it is relatively safe and makes no changes to the userspace interface. To summarize the main points of this patchset: there are no changes to the existing Counter sysfs userspace interface; a Counter character device interface is introduced that allows Counter events and associated data to be read() by userspace; the events_configure() and watch_validate() driver callbacks are introduced to support Counter events; and IRQ support is added to the 104-QUAD-8 driver, serving as an example of how to support the new Counter events functionality. Something that should still be discussed: should the struct counter_event "status" member be 8 bits or 32 bits wide? This member will provide the return status (system error number) of an event operation. William Breathitt Gray (22): docs: counter: Consolidate Counter sysfs attributes documentation docs: counter: Fix spelling counter: 104-quad-8: Return error when invalid mode during ceiling_write counter: 104-quad-8: Annotate hardware config module parameter counter: 104-quad-8: Add const qualifiers for quad8_preset_register_set counter: 104-quad-8: Add const qualifier for functions_list array counter: 104-quad-8: Add const qualifier for actions_list array counter: ftm-quaddec: Add const qualifier for actions_list array counter: Return error code on invalid modes counter: Standardize to ERANGE for limit exceeded errors counter: Rename counter_signal_value to counter_signal_level counter: Rename counter_count_function to counter_function counter: Internalize sysfs interface code counter: Update counter.h comments to reflect sysfs internalization docs: counter: Update to reflect sysfs internalization counter: Move counter enums to uapi header counter: Add character device interface docs: counter: Document character device interface counter: Implement extension*_name sysfs attributes counter: Implement events_queue_size sysfs attribute counter: 104-quad-8: Replace mutex with spinlock counter: 104-quad-8: Add IRQ support for the ACCES 104-QUAD-8 Documentation/ABI/testing/sysfs-bus-counter | 100 +- .../ABI/testing/sysfs-bus-counter-104-quad-8 | 61 - .../ABI/testing/sysfs-bus-counter-ftm-quaddec | 16 - Documentation/driver-api/generic-counter.rst | 426 ++++- .../userspace-api/ioctl/ioctl-number.rst | 1 + MAINTAINERS | 6 +- drivers/counter/104-quad-8.c | 751 +++++---- drivers/counter/Kconfig | 6 +- drivers/counter/Makefile | 1 + drivers/counter/counter-chrdev.c | 519 ++++++ drivers/counter/counter-chrdev.h | 18 + drivers/counter/counter-core.c | 185 ++ drivers/counter/counter-sysfs.c | 889 ++++++++++ drivers/counter/counter-sysfs.h | 13 + drivers/counter/counter.c | 1496 ----------------- drivers/counter/ftm-quaddec.c | 69 +- drivers/counter/microchip-tcb-capture.c | 105 +- drivers/counter/stm32-lptimer-cnt.c | 186 +- drivers/counter/stm32-timer-cnt.c | 187 +-- drivers/counter/ti-eqep.c | 226 ++- include/linux/counter.h | 716 ++++---- include/linux/counter_enum.h | 45 - include/uapi/linux/counter.h | 126 ++ 23 files changed, 3363 insertions(+), 2785 deletions(-) delete mode 100644 Documentation/ABI/testing/sysfs-bus-counter-104-quad-8 delete mode 100644 Documentation/ABI/testing/sysfs-bus-counter-ftm-quaddec create mode 100644 drivers/counter/counter-chrdev.c create mode 100644 drivers/counter/counter-chrdev.h create mode 100644 drivers/counter/counter-core.c create mode 100644 drivers/counter/counter-sysfs.c create mode 100644 drivers/counter/counter-sysfs.h delete mode 100644 drivers/counter/counter.c delete mode 100644 include/linux/counter_enum.h create mode 100644 include/uapi/linux/counter.h base-commit: b72d4f6a5122a78941ce5a3147685d6a44939a75