summaryrefslogtreecommitdiff
path: root/Documentation/driver-api
diff options
context:
space:
mode:
authorLinus Torvalds <torvalds@linux-foundation.org>2019-07-09 19:07:00 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2019-07-09 19:07:00 +0300
commit2ec98f567888501df0140c858af5f5ea10216a6f (patch)
tree656e0a3d0bba600bf79ab98c85bfec24ddcb2115 /Documentation/driver-api
parent96407298ff6ef59c4554833d47d29c775d1e7652 (diff)
parent9b3b623804a67d2274ee372c1587926ab0275833 (diff)
downloadlinux-2ec98f567888501df0140c858af5f5ea10216a6f.tar.xz
Merge tag 'gpio-v5.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio
Pull GPIO updates from Linus Walleij: "This is the big slew of GPIO changes for the v5.3 kernel cycle. This is mostly incremental work this time. Three important things: - The FMC subsystem is deleted through my tree. This happens through GPIO as its demise was discussed in relation to a patch decoupling its GPIO implementation from the standard way of handling GPIO. As it turns out, that is not the only subsystem it reimplements and the authors think it is better do scratch it and start over using the proper kernel subsystems than try to polish the rust shiny. See the commit (ACKed by the maintainers) for details. - Arnd made a small devres patch that was ACKed by Greg and goes into the device core. - SPDX header change colissions may happen, because at times I've seen that quite a lot changed during the -rc:s in regards to SPDX. (It is good stuff, tglx has me convinced, and it is worth the occasional pain.) Apart from this is is nothing controversial or problematic. Summary: Core: - When a gpio_chip request GPIOs from itself, it can now fully control the line characteristics, both machine and consumer flags. This makes a lot of sense, but took some time before I figured out that this is how it has to work. - Several smallish documentation fixes. New drivers: - The PCA953x driver now supports the TI TCA9539. - The DaVinci driver now supports the K3 AM654 SoCs. Driver improvements: - Major overhaul and hardening of the OMAP driver by Russell King. - Starting to move some drivers to the new API passing irq_chip along with the gpio_chip when adding the gpio_chip instead of adding it separately. Unrelated: - Delete the FMC subsystem" * tag 'gpio-v5.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio: (87 commits) Revert "gpio: tegra: Clean-up debugfs initialisation" gpiolib: Use spinlock_t instead of struct spinlock gpio: stp-xway: allow compile-testing gpio: stp-xway: get rid of the #include <lantiq_soc.h> dependency gpio: stp-xway: improve module clock error handling gpio: stp-xway: simplify error handling in xway_stp_probe() gpiolib: Clarify use of non-sleeping functions gpiolib: Fix references to gpiod_[gs]et_*value_cansleep() variants gpiolib: Document new gpio_chip.init_valid_mask field Documentation: gpio: Fix reference to gpiod_get_array() gpio: pl061: drop duplicate printing of device name gpio: altera: Pass irqchip when adding gpiochip gpio: siox: Use devm_ managed gpiochip gpio: siox: Add struct device *dev helper variable gpio: siox: Pass irqchip when adding gpiochip drivers: gpio: amd-fch: make resource struct const devres: allow const resource arguments gpio: ath79: Pass irqchip when adding gpiochip gpio: tegra: Clean-up debugfs initialisation gpio: siox: Switch to IRQ_TYPE_NONE ...
Diffstat (limited to 'Documentation/driver-api')
-rw-r--r--Documentation/driver-api/gpio/consumer.rst4
-rw-r--r--Documentation/driver-api/gpio/driver.rst16
2 files changed, 9 insertions, 11 deletions
diff --git a/Documentation/driver-api/gpio/consumer.rst b/Documentation/driver-api/gpio/consumer.rst
index 5e4d8aa68913..9559aa3cbcef 100644
--- a/Documentation/driver-api/gpio/consumer.rst
+++ b/Documentation/driver-api/gpio/consumer.rst
@@ -283,8 +283,6 @@ To summarize::
gpiod_set_value(desc, 1); default (active high) high
gpiod_set_value(desc, 0); active low high
gpiod_set_value(desc, 1); active low low
- gpiod_set_value(desc, 0); default (active high) low
- gpiod_set_value(desc, 1); default (active high) high
gpiod_set_value(desc, 0); open drain low
gpiod_set_value(desc, 1); open drain high impedance
gpiod_set_value(desc, 0); open source high impedance
@@ -366,7 +364,7 @@ accessed sequentially.
The functions take three arguments:
* array_size - the number of array elements
* desc_array - an array of GPIO descriptors
- * array_info - optional information obtained from gpiod_array_get()
+ * array_info - optional information obtained from gpiod_get_array()
* value_bitmap - a bitmap to store the GPIOs' values (get) or
a bitmap of values to assign to the GPIOs (set)
diff --git a/Documentation/driver-api/gpio/driver.rst b/Documentation/driver-api/gpio/driver.rst
index 1ce7fcd0f989..4af9aae724f0 100644
--- a/Documentation/driver-api/gpio/driver.rst
+++ b/Documentation/driver-api/gpio/driver.rst
@@ -235,7 +235,7 @@ means that a pull up or pull-down resistor is available on the output of the
GPIO line, and this resistor is software controlled.
In discrete designs, a pull-up or pull-down resistor is simply soldered on
-the circuit board. This is not something we deal or model in software. The
+the circuit board. This is not something we deal with or model in software. The
most you will think about these lines is that they will very likely be
configured as open drain or open source (see the section above).
@@ -292,18 +292,18 @@ We can divide GPIO irqchips in two broad categories:
- HIERARCHICAL INTERRUPT CHIPS: this means that each GPIO line has a dedicated
irq line to a parent interrupt controller one level up. There is no need
- to inquire the GPIO hardware to figure out which line has figured, but it
- may still be necessary to acknowledge the interrupt and set up the
- configuration such as edge sensitivity.
+ to inquire the GPIO hardware to figure out which line has fired, but it
+ may still be necessary to acknowledge the interrupt and set up configuration
+ such as edge sensitivity.
Realtime considerations: a realtime compliant GPIO driver should not use
spinlock_t or any sleepable APIs (like PM runtime) as part of its irqchip
implementation.
-- spinlock_t should be replaced with raw_spinlock_t [1].
+- spinlock_t should be replaced with raw_spinlock_t.[1]
- If sleepable APIs have to be used, these can be done from the .irq_bus_lock()
and .irq_bus_unlock() callbacks, as these are the only slowpath callbacks
- on an irqchip. Create the callbacks if needed [2].
+ on an irqchip. Create the callbacks if needed.[2]
Cascaded GPIO irqchips
@@ -361,7 +361,7 @@ Cascaded GPIO irqchips usually fall in one of three categories:
Realtime considerations: this kind of handlers will be forced threaded on -RT,
and as result the IRQ core will complain that generic_handle_irq() is called
- with IRQ enabled and the same work around as for "CHAINED GPIO irqchips" can
+ with IRQ enabled and the same work-around as for "CHAINED GPIO irqchips" can
be applied.
- NESTED THREADED GPIO IRQCHIPS: these are off-chip GPIO expanders and any
@@ -418,7 +418,7 @@ symbol:
If there is a need to exclude certain GPIO lines from the IRQ domain handled by
these helpers, we can set .irq.need_valid_mask of the gpiochip before
-[devm_]gpiochip_add_data() is called. This allocates an .irq.valid_mask with as
+``[devm_]gpiochip_add_data()`` is called. This allocates an .irq.valid_mask with as
many bits set as there are GPIO lines in the chip, each bit representing line
0..n-1. Drivers can exclude GPIO lines by clearing bits from this mask. The mask
must be filled in before gpiochip_irqchip_add() or gpiochip_irqchip_add_nested()