diff options
Diffstat (limited to 'Documentation/driver-api/gpio')
| -rw-r--r-- | Documentation/driver-api/gpio/board.rst | 16 | ||||
| -rw-r--r-- | Documentation/driver-api/gpio/consumer.rst | 2 | ||||
| -rw-r--r-- | Documentation/driver-api/gpio/driver.rst | 6 | ||||
| -rw-r--r-- | Documentation/driver-api/gpio/drivers-on-gpio.rst | 4 |
4 files changed, 24 insertions, 4 deletions
diff --git a/Documentation/driver-api/gpio/board.rst b/Documentation/driver-api/gpio/board.rst index 25d62b2e9fd0..2c112553df84 100644 --- a/Documentation/driver-api/gpio/board.rst +++ b/Documentation/driver-api/gpio/board.rst @@ -177,3 +177,19 @@ mapping and is thus transparent to GPIO consumers. A set of functions such as gpiod_set_value() is available to work with the new descriptor-oriented interface. + +Boards using platform data can also hog GPIO lines by defining GPIO hog tables. + +.. code-block:: c + + struct gpiod_hog gpio_hog_table[] = { + GPIO_HOG("gpio.0", 10, "foo", GPIO_ACTIVE_LOW, GPIOD_OUT_HIGH), + { } + }; + +And the table can be added to the board code as follows:: + + gpiod_add_hogs(gpio_hog_table); + +The line will be hogged as soon as the gpiochip is created or - in case the +chip was created earlier - when the hog table is registered. diff --git a/Documentation/driver-api/gpio/consumer.rst b/Documentation/driver-api/gpio/consumer.rst index c71a50d85b50..aa03f389d41d 100644 --- a/Documentation/driver-api/gpio/consumer.rst +++ b/Documentation/driver-api/gpio/consumer.rst @@ -57,7 +57,7 @@ device that displays digits), an additional index argument can be specified:: enum gpiod_flags flags) For a more detailed description of the con_id parameter in the DeviceTree case -see Documentation/gpio/board.txt +see Documentation/driver-api/gpio/board.rst The flags parameter is used to optionally specify a direction and initial value for the GPIO. Values can be: diff --git a/Documentation/driver-api/gpio/driver.rst b/Documentation/driver-api/gpio/driver.rst index 505ee906d7d9..cbe0242842d1 100644 --- a/Documentation/driver-api/gpio/driver.rst +++ b/Documentation/driver-api/gpio/driver.rst @@ -44,7 +44,7 @@ common to each controller of that type: - methods to establish GPIO line direction - methods used to access GPIO line values - - method to set electrical configuration to a a given GPIO line + - method to set electrical configuration for a given GPIO line - method to return the IRQ number associated to a given GPIO line - flag saying whether calls to its methods may sleep - optional line names array to identify lines @@ -143,7 +143,7 @@ resistor will make the line tend to high level unless one of the transistors on the rail actively pulls it down. The level on the line will go as high as the VDD on the pull-up resistor, which -may be higher than the level supported by the transistor, achieveing a +may be higher than the level supported by the transistor, achieving a level-shift to the higher VDD. Integrated electronics often have an output driver stage in the form of a CMOS @@ -382,7 +382,7 @@ Real-Time compliance for GPIO IRQ chips Any provider of irqchips needs to be carefully tailored to support Real Time preemption. It is desirable that all irqchips in the GPIO subsystem keep this -in mind and does the proper testing to assure they are real time-enabled. +in mind and do the proper testing to assure they are real time-enabled. So, pay attention on above " RT_FULL:" notes, please. The following is a checklist to follow when preparing a driver for real time-compliance: diff --git a/Documentation/driver-api/gpio/drivers-on-gpio.rst b/Documentation/driver-api/gpio/drivers-on-gpio.rst index 7da0c1dd1f7a..f3a189320e11 100644 --- a/Documentation/driver-api/gpio/drivers-on-gpio.rst +++ b/Documentation/driver-api/gpio/drivers-on-gpio.rst @@ -85,6 +85,10 @@ hardware descriptions such as device tree or ACPI: any other serio bus to the system and makes it possible to connect drivers for e.g. keyboards and other PS/2 protocol based devices. +- cec-gpio: drivers/media/platform/cec-gpio/ is used to interact with a CEC + Consumer Electronics Control bus using only GPIO. It is used to communicate + with devices on the HDMI bus. + Apart from this there are special GPIO drivers in subsystems like MMC/SD to read card detect and write protect GPIO lines, and in the TTY serial subsystem to emulate MCTRL (modem control) signals CTS/RTS by using two GPIO lines. The |