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// Licensed under the Apache License, Version 2.0 or the MIT License.
// SPDX-License-Identifier: Apache-2.0 OR MIT
// Copyright Tock Contributors 2022.
//! Provides userspace applications with access to GPIO pins.
//!
//! GPIOs are presented through a driver interface with synchronous commands
//! and a callback for interrupts.
//!
//! This capsule takes an array of pins to expose as generic GPIOs.
//! Note that this capsule is used for general purpose GPIOs. Pins that are
//! attached to LEDs or buttons are generally wired directly to those capsules,
//! not through this capsule as an intermediary.
//!
//! Usage
//! -----
//!
//! ```rust,ignore
//! # use kernel::static_init;
//!
//! let gpio_pins = static_init!(
//! [Option<&'static sam4l::gpio::GPIOPin>; 4],
//! [Option<&sam4l::gpio::PB[14]>,
//! Option<&sam4l::gpio::PB[15]>,
//! Option<&sam4l::gpio::PB[11]>,
//! Option<&sam4l::gpio::PB[12]>]);
//! let gpio = static_init!(
//! capsules_core::gpio::GPIO<'static, sam4l::gpio::GPIOPin>,
//! capsules_core::gpio::GPIO::new(gpio_pins));
//! for maybe_pin in gpio_pins.iter() {
//! if let Some(pin) = maybe_pin {
//! pin.set_client(gpio);
//! }
//! }
//! ```
//!
//! Syscall Interface
//! -----------------
//!
//! - Stability: 2 - Stable
//!
//! ### Commands
//!
//! All GPIO operations are synchronous.
//!
//! Commands control and query GPIO information, namely how many GPIOs are
//! present, the GPIO direction and state, and whether they should interrupt.
//!
//! ### Subscribes
//!
//! The GPIO interface provides only one callback, which is used for pins that
//! have had interrupts enabled.
/// Syscall driver number.
use crate::driver;
pub const DRIVER_NUM: usize = driver::NUM::Gpio as usize;
use kernel::grant::{AllowRoCount, AllowRwCount, Grant, UpcallCount};
use kernel::hil::gpio;
use kernel::hil::gpio::{Configure, Input, InterruptWithValue, Output};
use kernel::syscall::{CommandReturn, SyscallDriver};
use kernel::{ErrorCode, ProcessId};
/// ### `subscribe_num`
///
/// - `0`: Subscribe to interrupts from all pins with interrupts enabled.
/// The callback signature is `fn(pin_num: usize, pin_state: bool)`
const UPCALL_NUM: usize = 0;
pub struct GPIO<'a, IP: gpio::InterruptPin<'a>> {
pins: &'a [Option<&'a gpio::InterruptValueWrapper<'a, IP>>],
apps: Grant<(), UpcallCount<1>, AllowRoCount<0>, AllowRwCount<0>>,
}
impl<'a, IP: gpio::InterruptPin<'a>> GPIO<'a, IP> {
pub fn new(
pins: &'a [Option<&'a gpio::InterruptValueWrapper<'a, IP>>],
grant: Grant<(), UpcallCount<1>, AllowRoCount<0>, AllowRwCount<0>>,
) -> Self {
for (i, maybe_pin) in pins.iter().enumerate() {
if let Some(pin) = maybe_pin {
pin.set_value(i as u32);
}
}
Self { pins, apps: grant }
}
fn configure_input_pin(&self, pin_num: u32, config: usize) -> CommandReturn {
let maybe_pin = self.pins[pin_num as usize];
if let Some(pin) = maybe_pin {
pin.make_input();
match config {
0 => {
pin.set_floating_state(gpio::FloatingState::PullNone);
CommandReturn::success()
}
1 => {
pin.set_floating_state(gpio::FloatingState::PullUp);
CommandReturn::success()
}
2 => {
pin.set_floating_state(gpio::FloatingState::PullDown);
CommandReturn::success()
}
_ => CommandReturn::failure(ErrorCode::NOSUPPORT),
}
} else {
CommandReturn::failure(ErrorCode::NODEVICE)
}
}
fn configure_interrupt(&self, pin_num: u32, config: usize) -> CommandReturn {
let pins = self.pins;
let index = pin_num as usize;
if let Some(pin) = pins[index] {
match config {
0 => {
let _ = pin.enable_interrupts(gpio::InterruptEdge::EitherEdge);
CommandReturn::success()
}
1 => {
let _ = pin.enable_interrupts(gpio::InterruptEdge::RisingEdge);
CommandReturn::success()
}
2 => {
let _ = pin.enable_interrupts(gpio::InterruptEdge::FallingEdge);
CommandReturn::success()
}
_ => CommandReturn::failure(ErrorCode::NOSUPPORT),
}
} else {
CommandReturn::failure(ErrorCode::NODEVICE)
}
}
}
impl<'a, IP: gpio::InterruptPin<'a>> gpio::ClientWithValue for GPIO<'a, IP> {
fn fired(&self, pin_num: u32) {
// read the value of the pin
let pins = self.pins;
if let Some(pin) = pins[pin_num as usize] {
let pin_state = pin.read();
// schedule callback with the pin number and value
self.apps.each(|_, _, upcalls| {
upcalls
.schedule_upcall(UPCALL_NUM, (pin_num as usize, pin_state as usize, 0))
.ok();
});
}
}
}
impl<'a, IP: gpio::InterruptPin<'a>> SyscallDriver for GPIO<'a, IP> {
/// Query and control pin values and states.
///
/// Each byte of the `data` argument is treated as its own field.
/// For all commands, the lowest order halfword is the pin number (`pin`).
/// A few commands use higher order bytes for purposes documented below.
/// If the higher order bytes are not used, they must be set to `0`.
///
/// Other data bytes:
///
/// - `pin_config`: An internal resistor setting.
/// Set to `0` for a pull-up resistor.
/// Set to `1` for a pull-down resistor.
/// Set to `2` for none.
/// - `irq_config`: Interrupt configuration setting.
/// Set to `0` to interrupt on either edge.
/// Set to `1` for rising edge.
/// Set to `2` for falling edge.
///
/// ### `command_num`
///
/// - `0`: Driver existence check.
/// - `1`: Enable output on `pin`.
/// - `2`: Set `pin`.
/// - `3`: Clear `pin`.
/// - `4`: Toggle `pin`.
/// - `5`: Enable input on `pin` with `pin_config` in 0x00XX00000
/// - `6`: Read `pin` value.
/// - `7`: Configure interrupt on `pin` with `irq_config` in 0x00XX00000
/// - `8`: Disable interrupt on `pin`.
/// - `9`: Disable `pin`.
/// - `10`: Get number of GPIO ports supported.
fn command(
&self,
command_num: usize,
data1: usize,
data2: usize,
_: ProcessId,
) -> CommandReturn {
let pins = self.pins;
let pin_index = data1;
match command_num {
// Check existence.
0 => CommandReturn::success(),
// enable output
1 => {
if pin_index >= pins.len() {
/* impossible pin */
CommandReturn::failure(ErrorCode::INVAL)
} else {
if let Some(pin) = pins[pin_index] {
pin.make_output();
CommandReturn::success()
} else {
CommandReturn::failure(ErrorCode::NODEVICE)
}
}
}
// set pin
2 => {
if pin_index >= pins.len() {
/* impossible pin */
CommandReturn::failure(ErrorCode::INVAL)
} else {
if let Some(pin) = pins[pin_index] {
pin.set();
CommandReturn::success()
} else {
CommandReturn::failure(ErrorCode::NODEVICE)
}
}
}
// clear pin
3 => {
if pin_index >= pins.len() {
/* impossible pin */
CommandReturn::failure(ErrorCode::INVAL)
} else {
if let Some(pin) = pins[pin_index] {
pin.clear();
CommandReturn::success()
} else {
CommandReturn::failure(ErrorCode::NODEVICE)
}
}
}
// toggle pin
4 => {
if pin_index >= pins.len() {
/* impossible pin */
CommandReturn::failure(ErrorCode::INVAL)
} else {
if let Some(pin) = pins[pin_index] {
pin.toggle();
CommandReturn::success()
} else {
CommandReturn::failure(ErrorCode::NODEVICE)
}
}
}
// enable and configure input
5 => {
let pin_config = data2;
if pin_index >= pins.len() {
/* impossible pin */
CommandReturn::failure(ErrorCode::INVAL)
} else {
self.configure_input_pin(pin_index as u32, pin_config)
}
}
// read input
6 => {
if pin_index >= pins.len() {
/* impossible pin */
CommandReturn::failure(ErrorCode::INVAL)
} else {
if let Some(pin) = pins[pin_index] {
let pin_state = pin.read();
CommandReturn::success_u32(pin_state as u32)
} else {
CommandReturn::failure(ErrorCode::NODEVICE)
}
}
}
// configure interrupts on pin
// (no affect or reliance on registered callback)
7 => {
let irq_config = data2;
if pin_index >= pins.len() {
/* impossible pin */
CommandReturn::failure(ErrorCode::INVAL)
} else {
self.configure_interrupt(pin_index as u32, irq_config)
}
}
// disable interrupts on pin, also disables pin
// (no affect or reliance on registered callback)
8 => {
if pin_index >= pins.len() {
/* impossible pin */
CommandReturn::failure(ErrorCode::INVAL)
} else {
if let Some(pin) = pins[pin_index] {
pin.disable_interrupts();
pin.deactivate_to_low_power();
CommandReturn::success()
} else {
CommandReturn::failure(ErrorCode::NODEVICE)
}
}
}
// disable pin
9 => {
if pin_index >= pins.len() {
/* impossible pin */
CommandReturn::failure(ErrorCode::INVAL)
} else {
if let Some(pin) = pins[pin_index] {
pin.deactivate_to_low_power();
CommandReturn::success()
} else {
CommandReturn::failure(ErrorCode::NODEVICE)
}
}
}
// number of pins
10 => CommandReturn::success_u32(pins.len() as u32),
// default
_ => CommandReturn::failure(ErrorCode::NOSUPPORT),
}
}
fn allocate_grant(&self, processid: ProcessId) -> Result<(), kernel::process::Error> {
self.apps.enter(processid, |_, _| {})
}
}