Merge tag 'gpio-updates-for-v6.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/brgl/linux

Pull gpio updates from Bartosz Golaszewski: "The majority of added lines are two new modules: the GPIO virtual consumer module that improves our ability to add automated tests for the kernel API and the "sloppy" logic analyzer module that uses the GPIO API to implement a coarse-grained debugging tool for useful for remote development. Other than that we have the usual assortment of various driver extensions, improvements to the core GPIO code, DT-bindings and other documentation updates as well as an extension to the interrupt simulator: GPIOLIB core: - rework kfifo handling rework in the character device code - improve the labeling of GPIOs requested as interrupts and show more info on interrupt-only GPIOs in debugfs - remove unused APIs - unexport interfaces that are only used from the core GPIO code - drop the return value from gpiochip_set_desc_names() as it cannot fail - move a string array definition out of a header and into a specific compilation unit - convert the last user of gpiochip_get_desc() other than GPIO core to using a safer alternative - use array_index_nospec() where applicable New drivers: - add a "virtual GPIO consumer" module that allows requesting GPIOs from actual hardware and driving tests of the in-kernel GPIO API from user-space over debugfs - add a GPIO-based "sloppy" logic analyzer module useful for "first glance" debugging on remote boards Driver improvements: - add support for a new model to gpio-pca953x - lock GPIOs as interrupts in gpio-sim when the lines are requested as irqs via the simulator domain + some other minor improvements - improve error reporting in gpio-syscon - convert gpio-ath79 to using dynamic GPIO base and range - use pcibios_err_to_errno() for converting PCIBIOS error codes to errno vaues in gpio-amd8111 and gpio-rdc321x - allow building gpio-brcmstb for the BCM2835 architecture DT bindings: - convert DT bindings for lsi,zevio, mpc8xxx, and atmel to DT schema - document new properties for aspeed,gpio, fsl,qoriq-gpio and gpio-vf610 - document new compatibles for pca953x and fsl,qoriq-gpio Documentation: - document stricter behavior of the GPIO character device uAPI with regards to reconfiguring requested line without direction set - clarify the effect of the active-low flag on line values and edges - remove documentation for the legacy GPIO API in order to stop tempting people to use it - document the preference for using pread() for reading edge events in the sysfs API Other: - add an extended initializer to the interrupt simulator allowing to specify a number of callbacks callers can use to be notified about irqs being requested and released" * tag 'gpio-updates-for-v6.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/brgl/linux: (41 commits) gpio: mc33880: Convert comma to semicolon gpio: virtuser: actually use the "trimmed" local variable dt-bindings: gpio: convert Atmel GPIO to json-schema gpio: virtuser: new virtual testing driver for the GPIO API dt-bindings: gpio: vf610: Allow gpio-line-names to be set gpio: sim: lock GPIOs as interrupts when they are requested genirq/irq_sim: add an extended irq_sim initializer dt-bindings: gpio: fsl,qoriq-gpio: Add compatible string fsl,ls1046a-gpio gpiolib: unexport gpiochip_get_desc() gpio: add sloppy logic analyzer using polling Documentation: gpio: Reconfiguration with unset direction (uAPI v2) Documentation: gpio: Reconfiguration with unset direction (uAPI v1) dt-bindings: gpio: fsl,qoriq-gpio: add common property gpio-line-names gpio: ath79: convert to dynamic GPIO base allocation pinctrl: da9062: replace gpiochip_get_desc() with gpio_device_get_desc() gpiolib: put gpio_suffixes in a single compilation unit Documentation: gpio: Clarify effect of active low flag on line edges Documentation: gpio: Clarify effect of active low flag on line values gpiolib: Remove data-less gpiochip_add() function gpio: sim: use devm_mutex_init() ...
2024-07-15 17:53:24 -07:00
parent 3f32ab146c dfda97e37d
commit b3c0eccb48
54 changed files with 3187 additions and 2123 deletions
@@ -36,6 +36,13 @@ Description

 Get the values of all requested lines.

+The values returned are logical, indicating if the line is active or inactive.
+The ``GPIOHANDLE_REQUEST_ACTIVE_LOW`` flag controls the mapping between physical
+values (high/low) and logical values (active/inactive).
+If ``GPIOHANDLE_REQUEST_ACTIVE_LOW`` is not set then high is active and
+low is inactive. If ``GPIOHANDLE_REQUEST_ACTIVE_LOW`` is set then low is active
+and high is inactive.
+
 The values of both input and output lines may be read.

 For output lines, the value returned is driver and configuration dependent and
@@ -43,7 +43,10 @@ The configuration applies to all requested lines.

 The same :ref:`gpio-get-linehandle-config-rules` and
 :ref:`gpio-get-linehandle-config-support` that apply when requesting the
-lines also apply when updating the line configuration.
+lines also apply when updating the line configuration, with the additional
+restriction that a direction flag must be set. Requesting an invalid
+configuration, including without a direction flag set, is an error
+(**EINVAL**).

 The motivating use case for this command is changing direction of
 bi-directional lines between input and output, but it may be used more
@@ -36,6 +36,13 @@ Description

 Set the values of all requested output lines.

+The values set are logical, indicating if the line is to be active or inactive.
+The ``GPIOHANDLE_REQUEST_ACTIVE_LOW`` flag controls the mapping between logical
+values (active/inactive) and physical values (high/low).
+If  ``GPIOHANDLE_REQUEST_ACTIVE_LOW`` is not set then active is high and
+inactive is low. If ``GPIOHANDLE_REQUEST_ACTIVE_LOW`` is set then active is low
+and inactive is high.
+
 Only the values of output lines may be set.
 Attempting to set the value of input lines is an error (**EPERM**).

@@ -44,6 +44,11 @@ Edge detection must be enabled for the input line using either
 both. Edge events are then generated whenever edge interrupts are detected on
 the input line.

+Edges are defined in terms of changes to the logical line value, so an inactive
+to active transition is a rising edge.  If ``GPIOHANDLE_REQUEST_ACTIVE_LOW`` is
+set then logical polarity is the opposite of physical polarity, and
+``GPIOEVENT_REQUEST_RISING_EDGE`` then corresponds to a falling physical edge.
+
 The kernel captures and timestamps edge events as close as possible to their
 occurrence and stores them in a buffer from where they can be read by
 userspace at its convenience using `read()`.
@@ -40,6 +40,11 @@ Edge detection must be enabled for the input line using either
 both. Edge events are then generated whenever edge interrupts are detected on
 the input line.

+Edges are defined in terms of changes to the logical line value, so an inactive
+to active transition is a rising edge.  If ``GPIO_V2_LINE_FLAG_ACTIVE_LOW`` is
+set then logical polarity is the opposite of physical polarity, and
+``GPIO_V2_LINE_FLAG_EDGE_RISING`` then corresponds to a falling physical edge.
+
 The kernel captures and timestamps edge events as close as possible to their
 occurrence and stores them in a buffer from where they can be read by
 userspace at its convenience using `read()`.
@@ -34,6 +34,13 @@ Description

 Get the values of requested lines.

+The values returned are logical, indicating if the line is active or inactive.
+The ``GPIO_V2_LINE_FLAG_ACTIVE_LOW`` flag controls the mapping between physical
+values (high/low) and logical values (active/inactive).
+If ``GPIO_V2_LINE_FLAG_ACTIVE_LOW`` is not set then high is active and low is
+inactive.  If ``GPIO_V2_LINE_FLAG_ACTIVE_LOW`` is set then low is active and
+high is inactive.
+
 The values of both input and output lines may be read.

 For output lines, the value returned is driver and configuration dependent and
@@ -35,11 +35,14 @@ Description
 Update the configuration of previously requested lines, without releasing the
 line or introducing potential glitches.

-The new configuration must specify the configuration of all requested lines.
+The new configuration must specify a configuration for all requested lines.

 The same :ref:`gpio-v2-get-line-config-rules` and
 :ref:`gpio-v2-get-line-config-support` that apply when requesting the lines
-also apply when updating the line configuration.
+also apply when updating the line configuration, with the additional
+restriction that a direction flag must be set to enable reconfiguration.
+If no direction flag is set in the configuration for a given line then the
+configuration for that line is left unchanged.

 The motivating use case for this command is changing direction of
 bi-directional lines between input and output, but it may also be used to
@@ -35,6 +35,13 @@ Description

 Set the values of requested output lines.

+The values set are logical, indicating if the line is to be active or inactive.
+The ``GPIO_V2_LINE_FLAG_ACTIVE_LOW`` flag controls the mapping between logical
+values (active/inactive) and physical values (high/low).
+If ``GPIO_V2_LINE_FLAG_ACTIVE_LOW`` is not set then active is high and inactive
+is low.  If ``GPIO_V2_LINE_FLAG_ACTIVE_LOW`` is set then active is low and
+inactive is high.
+
 Only the values of output lines may be set.
 Attempting to set the value of an input line is an error (**EPERM**).

@@ -97,9 +97,10 @@ and have the following read/write attributes:
 		poll(2) will return whenever the interrupt was triggered. If
 		you use poll(2), set the events POLLPRI and POLLERR. If you
 		use select(2), set the file descriptor in exceptfds. After
-		poll(2) returns, either lseek(2) to the beginning of the sysfs
-		file and read the new value or close the file and re-open it
-		to read the value.
+		poll(2) returns, use pread(2) to read the value at offset
+		zero. Alternatively, either lseek(2) to the beginning of the
+		sysfs file and read the new value or close the file and
+		re-open it to read the value.

 	"edge" ...
 		reads as either "none", "rising", "falling", or