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authorLinus Torvalds <torvalds@linux-foundation.org>2020-01-29 09:43:39 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2020-01-29 09:43:39 -0800
commitfa889d85551e0bd962fdefe1cc113f9ba1d04a36 (patch)
tree4f74147dc17e9fa39d06053a949c5491ccf2bace /Documentation
parentb3a6082223369203d7e7db7e81253ac761377644 (diff)
parent0282c72d30d32913d641dc81f3f38607ace98802 (diff)
Merge tag 'gpio-v5.6-1' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio
Pull GPIO updates from Linus Walleij: "This is the bulk of GPIO changes for the v5.6 kernel cycle. This is a pretty calm cycle so far, nothing special going on really. Some more changes will come in from the irqchip and pin control trees. I also deleted an orphan include file for FMC that was dangling since subsystem was removed. Core changes: - Document the usecases for the kernelspace vs userspace handling of GPIOs. - Handle MSI (message signalled interrupts) properly in the core hierarchical irqdomain code. - Fix a rare race condition while initializing the descriptor array. New drivers: - Xylon LogiCVC GPIO driver. - WDC934x GPIO controller driver. Driver improvements: - Implemented suspend/resume in the Tegra driver. - MPC8xx edge detection fixup. - Properly convert ThunderX to use hierarchical irqdomain with GPIOLIB_IRQCHIP on top of the revert of the previous buggy switchover. This time it works (hopefully). Misc: - Drop a FMC remnant file <linux/ipmi-fru.h> - A slew of fixes" * tag 'gpio-v5.6-1' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio: (48 commits) MAINTAINERS: Replace Tien Hock Loh as Altera PIO maintainer gpiolib: hold gpio devices lock until ->descs array is initialised gpio: aspeed-sgpio: fixed typos gpio: mvebu: clear irq in edge cause register before unmask edge irq gpiolib: Lower verbosity when allocating hierarchy irq gpiolib: Remove duplicated function gpio_do_set_config() gpio: Fix the no return statement warning gpio: wcd934x: Add support to wcd934x gpio controller gpiolib: remove set but not used variable 'config' gpio: vx855: fixed a typo gpio: mockup: sort headers alphabetically gpio: mockup: update the license tag gpio: Remove the unused flags gpiolib: Set lockdep class for hierarchical irq domains gpio: thunderx: Switch to GPIOLIB_IRQCHIP gpiolib: Add the support for the msi parent domain gpiolib: Add support for the irqdomain which doesn't use irq_fwspec as arg gpio: Add use guidance documentation dt-bindings: gpio: wcd934x: Add bindings for gpio gpio: altera: change to platform_get_irq_optional to avoid false-positive error ...
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/devicetree/bindings/gpio/qcom,wcd934x-gpio.yaml47
-rw-r--r--Documentation/devicetree/bindings/gpio/renesas,gpio-rcar.txt3
-rw-r--r--Documentation/devicetree/bindings/gpio/xylon,logicvc-gpio.yaml69
-rw-r--r--Documentation/devicetree/bindings/mfd/xylon,logicvc.yaml50
-rw-r--r--Documentation/devicetree/bindings/vendor-prefixes.yaml2
-rw-r--r--Documentation/driver-api/driver-model/devres.rst2
-rw-r--r--Documentation/driver-api/gpio/drivers-on-gpio.rst8
-rw-r--r--Documentation/driver-api/gpio/index.rst1
-rw-r--r--Documentation/driver-api/gpio/using-gpio.rst50
9 files changed, 227 insertions, 5 deletions
diff --git a/Documentation/devicetree/bindings/gpio/qcom,wcd934x-gpio.yaml b/Documentation/devicetree/bindings/gpio/qcom,wcd934x-gpio.yaml
new file mode 100644
index 000000000000..32a566ec3558
--- /dev/null
+++ b/Documentation/devicetree/bindings/gpio/qcom,wcd934x-gpio.yaml
@@ -0,0 +1,47 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/gpio/qcom,wcd934x-gpio.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: WCD9340/WCD9341 GPIO controller
+
+maintainers:
+ - Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
+
+description: |
+ Qualcomm Technologies Inc WCD9340/WCD9341 Audio Codec has integrated
+ gpio controller to control 5 gpios on the chip.
+
+properties:
+ compatible:
+ enum:
+ - qcom,wcd9340-gpio
+ - qcom,wcd9341-gpio
+
+ reg:
+ maxItems: 1
+
+ gpio-controller: true
+
+ '#gpio-cells':
+ const: 2
+
+required:
+ - compatible
+ - reg
+ - gpio-controller
+ - "#gpio-cells"
+
+additionalProperties: false
+
+examples:
+ - |
+ wcdgpio: gpio@42 {
+ compatible = "qcom,wcd9340-gpio";
+ reg = <0x042 0x2>;
+ gpio-controller;
+ #gpio-cells = <2>;
+ };
+
+...
diff --git a/Documentation/devicetree/bindings/gpio/renesas,gpio-rcar.txt b/Documentation/devicetree/bindings/gpio/renesas,gpio-rcar.txt
index 41e5fed0f842..10dce84b1545 100644
--- a/Documentation/devicetree/bindings/gpio/renesas,gpio-rcar.txt
+++ b/Documentation/devicetree/bindings/gpio/renesas,gpio-rcar.txt
@@ -18,7 +18,8 @@ Required Properties:
- "renesas,gpio-r8a7793": for R8A7793 (R-Car M2-N) compatible GPIO controller.
- "renesas,gpio-r8a7794": for R8A7794 (R-Car E2) compatible GPIO controller.
- "renesas,gpio-r8a7795": for R8A7795 (R-Car H3) compatible GPIO controller.
- - "renesas,gpio-r8a7796": for R8A7796 (R-Car M3-W) compatible GPIO controller.
+ - "renesas,gpio-r8a7796": for R8A77960 (R-Car M3-W) compatible GPIO controller.
+ - "renesas,gpio-r8a77961": for R8A77961 (R-Car M3-W+) compatible GPIO controller.
- "renesas,gpio-r8a77965": for R8A77965 (R-Car M3-N) compatible GPIO controller.
- "renesas,gpio-r8a77970": for R8A77970 (R-Car V3M) compatible GPIO controller.
- "renesas,gpio-r8a77980": for R8A77980 (R-Car V3H) compatible GPIO controller.
diff --git a/Documentation/devicetree/bindings/gpio/xylon,logicvc-gpio.yaml b/Documentation/devicetree/bindings/gpio/xylon,logicvc-gpio.yaml
new file mode 100644
index 000000000000..d102888c1be7
--- /dev/null
+++ b/Documentation/devicetree/bindings/gpio/xylon,logicvc-gpio.yaml
@@ -0,0 +1,69 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+# Copyright 2019 Bootlin
+%YAML 1.2
+---
+$id: "http://devicetree.org/schemas/gpio/xylon,logicvc-gpio.yaml#"
+$schema: "http://devicetree.org/meta-schemas/core.yaml#"
+
+title: Xylon LogiCVC GPIO controller
+
+maintainers:
+ - Paul Kocialkowski <paul.kocialkowski@bootlin.com>
+
+description: |
+ The LogiCVC GPIO describes the GPIO block included in the LogiCVC display
+ controller. These are meant to be used for controlling display-related
+ signals.
+
+ The controller exposes GPIOs from the display and power control registers,
+ which are mapped by the driver as follows:
+ - GPIO[4:0] (display control) mapped to index 0-4
+ - EN_BLIGHT (power control) mapped to index 5
+ - EN_VDD (power control) mapped to index 6
+ - EN_VEE (power control) mapped to index 7
+ - V_EN (power control) mapped to index 8
+
+properties:
+ $nodename:
+ pattern: "^gpio@[0-9a-f]+$"
+
+ compatible:
+ enum:
+ - xylon,logicvc-3.02.a-gpio
+
+ reg:
+ maxItems: 1
+
+ "#gpio-cells":
+ const: 2
+
+ gpio-controller: true
+
+ gpio-line-names:
+ minItems: 1
+ maxItems: 9
+
+required:
+ - compatible
+ - reg
+ - "#gpio-cells"
+ - gpio-controller
+
+examples:
+ - |
+ logicvc: logicvc@43c00000 {
+ compatible = "xylon,logicvc-3.02.a", "syscon", "simple-mfd";
+ reg = <0x43c00000 0x6000>;
+
+ #address-cells = <1>;
+ #size-cells = <1>;
+
+ logicvc_gpio: gpio@40 {
+ compatible = "xylon,logicvc-3.02.a-gpio";
+ reg = <0x40 0x40>;
+ gpio-controller;
+ #gpio-cells = <2>;
+ gpio-line-names = "GPIO0", "GPIO1", "GPIO2", "GPIO3", "GPIO4",
+ "EN_BLIGHT", "EN_VDD", "EN_VEE", "V_EN";
+ };
+ };
diff --git a/Documentation/devicetree/bindings/mfd/xylon,logicvc.yaml b/Documentation/devicetree/bindings/mfd/xylon,logicvc.yaml
new file mode 100644
index 000000000000..abc9937506e0
--- /dev/null
+++ b/Documentation/devicetree/bindings/mfd/xylon,logicvc.yaml
@@ -0,0 +1,50 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+# Copyright 2019 Bootlin
+%YAML 1.2
+---
+$id: "http://devicetree.org/schemas/mfd/xylon,logicvc.yaml#"
+$schema: "http://devicetree.org/meta-schemas/core.yaml#"
+
+title: Xylon LogiCVC multi-function device
+
+maintainers:
+ - Paul Kocialkowski <paul.kocialkowski@bootlin.com>
+
+description: |
+ The LogiCVC is a display controller that also contains a GPIO controller.
+ As a result, a multi-function device is exposed as parent of the display
+ and GPIO blocks.
+
+properties:
+ compatible:
+ items:
+ - enum:
+ - xylon,logicvc-3.02.a
+ - const: syscon
+ - const: simple-mfd
+
+ reg:
+ maxItems: 1
+
+select:
+ properties:
+ compatible:
+ contains:
+ enum:
+ - xylon,logicvc-3.02.a
+
+ required:
+ - compatible
+
+required:
+ - compatible
+ - reg
+
+examples:
+ - |
+ logicvc: logicvc@43c00000 {
+ compatible = "xylon,logicvc-3.02.a", "syscon", "simple-mfd";
+ reg = <0x43c00000 0x6000>;
+ #address-cells = <1>;
+ #size-cells = <1>;
+ };
diff --git a/Documentation/devicetree/bindings/vendor-prefixes.yaml b/Documentation/devicetree/bindings/vendor-prefixes.yaml
index 6046f4555852..9cb3bc683db7 100644
--- a/Documentation/devicetree/bindings/vendor-prefixes.yaml
+++ b/Documentation/devicetree/bindings/vendor-prefixes.yaml
@@ -1060,6 +1060,8 @@ patternProperties:
description: Xilinx
"^xunlong,.*":
description: Shenzhen Xunlong Software CO.,Limited
+ "^xylon,.*":
+ description: Xylon
"^yones-toptech,.*":
description: Yones Toptech Co., Ltd.
"^ysoft,.*":
diff --git a/Documentation/driver-api/driver-model/devres.rst b/Documentation/driver-api/driver-model/devres.rst
index 20e07e40be02..46c13780994c 100644
--- a/Documentation/driver-api/driver-model/devres.rst
+++ b/Documentation/driver-api/driver-model/devres.rst
@@ -267,6 +267,8 @@ DRM
GPIO
devm_gpiod_get()
+ devm_gpiod_get_array()
+ devm_gpiod_get_array_optional()
devm_gpiod_get_index()
devm_gpiod_get_index_optional()
devm_gpiod_get_optional()
diff --git a/Documentation/driver-api/gpio/drivers-on-gpio.rst b/Documentation/driver-api/gpio/drivers-on-gpio.rst
index f3a189320e11..820b403d50f6 100644
--- a/Documentation/driver-api/gpio/drivers-on-gpio.rst
+++ b/Documentation/driver-api/gpio/drivers-on-gpio.rst
@@ -95,7 +95,7 @@ to emulate MCTRL (modem control) signals CTS/RTS by using two GPIO lines. The
MTD NOR flash has add-ons for extra GPIO lines too, though the address bus is
usually connected directly to the flash.
-Use those instead of talking directly to the GPIOs using sysfs; they integrate
-with kernel frameworks better than your userspace code could. Needless to say,
-just using the appropriate kernel drivers will simplify and speed up your
-embedded hacking in particular by providing ready-made components.
+Use those instead of talking directly to the GPIOs from userspace; they
+integrate with kernel frameworks better than your userspace code could.
+Needless to say, just using the appropriate kernel drivers will simplify and
+speed up your embedded hacking in particular by providing ready-made components.
diff --git a/Documentation/driver-api/gpio/index.rst b/Documentation/driver-api/gpio/index.rst
index 5b61032aa4ea..1d48fe248f05 100644
--- a/Documentation/driver-api/gpio/index.rst
+++ b/Documentation/driver-api/gpio/index.rst
@@ -8,6 +8,7 @@ Contents:
:maxdepth: 2
intro
+ using-gpio
driver
consumer
board
diff --git a/Documentation/driver-api/gpio/using-gpio.rst b/Documentation/driver-api/gpio/using-gpio.rst
new file mode 100644
index 000000000000..dda069444032
--- /dev/null
+++ b/Documentation/driver-api/gpio/using-gpio.rst
@@ -0,0 +1,50 @@
+=========================
+Using GPIO Lines in Linux
+=========================
+
+The Linux kernel exists to abstract and present hardware to users. GPIO lines
+as such are normally not user facing abstractions. The most obvious, natural
+and preferred way to use GPIO lines is to let kernel hardware drivers deal
+with them.
+
+For examples of already existing generic drivers that will also be good
+examples for any other kernel drivers you want to author, refer to
+:doc:`drivers-on-gpio`
+
+For any kind of mass produced system you want to support, such as servers,
+laptops, phones, tablets, routers, and any consumer or office or business goods
+using appropriate kernel drivers is paramount. Submit your code for inclusion
+in the upstream Linux kernel when you feel it is mature enough and you will get
+help to refine it, see :doc:`../../process/submitting-patches`.
+
+In Linux GPIO lines also have a userspace ABI.
+
+The userspace ABI is intended for one-off deployments. Examples are prototypes,
+factory lines, maker community projects, workshop specimen, production tools,
+industrial automation, PLC-type use cases, door controllers, in short a piece
+of specialized equipment that is not produced by the numbers, requiring
+operators to have a deep knowledge of the equipment and knows about the
+software-hardware interface to be set up. They should not have a natural fit
+to any existing kernel subsystem and not be a good fit for an operating system,
+because of not being reusable or abstract enough, or involving a lot of non
+computer hardware related policy.
+
+Applications that have a good reason to use the industrial I/O (IIO) subsystem
+from userspace will likely be a good fit for using GPIO lines from userspace as
+well.
+
+Do not under any circumstances abuse the GPIO userspace ABI to cut corners in
+any product development projects. If you use it for prototyping, then do not
+productify the prototype: rewrite it using proper kernel drivers. Do not under
+any circumstances deploy any uniform products using GPIO from userspace.
+
+The userspace ABI is a character device for each GPIO hardware unit (GPIO chip).
+These devices will appear on the system as ``/dev/gpiochip0`` thru
+``/dev/gpiochipN``. Examples of how to directly use the userspace ABI can be
+found in the kernel tree ``tools/gpio`` subdirectory.
+
+For structured and managed applications, we recommend that you make use of the
+libgpiod_ library. This provides helper abstractions, command line utlities
+and arbitration for multiple simultaneous consumers on the same GPIO chip.
+
+.. _libgpiod: https://git.kernel.org/pub/scm/libs/libgpiod/libgpiod.git/