Crazypedia f13c18f398
LoRa device type + SX1262 kernel driver (first checkpoint) (#565)
Adds sub-GHz radio support to Tactility as a first-class kernel device type, plus a
driver for the Semtech SX1262. Continues the radio work discussed in #342, brought up to
the current kernel driver model (rather than the deprecated tt::hal layer the earlier
prototype targeted).
2026-07-30 19:32:23 +02:00

278 lines
11 KiB
C

// SPDX-License-Identifier: Apache-2.0
#pragma once
#include <stdbool.h>
#include <stddef.h>
#include <stdint.h>
#include <tactility/error.h>
#ifdef __cplusplus
extern "C" {
#endif
struct Device;
/**
* Device type and API for sub-GHz packet transceivers such as the Semtech SX126x family.
* The API is LoRa-centric but exposes the modem's other modulation schemes as well.
*/
enum LoraModulation {
LORA_MODULATION_NONE = 0,
LORA_MODULATION_FSK,
LORA_MODULATION_LORA,
LORA_MODULATION_LR_FHSS,
};
/**
* Tunable radio parameters. Values are int32_t; the unit is documented per parameter.
* Frequencies and rates use their base SI unit (Hz, bit/s) on purpose: a float can't hold
* a value like 906875000 Hz (906.875 MHz) exactly, so integers avoid the rounding a
* fractional MHz/kHz representation would introduce.
*
* Which parameters are available depends on the driver and the selected modulation.
*/
enum LoraParameter {
/** TX output power in dBm */
LORA_PARAMETER_POWER = 0,
/** Boosted RX gain mode: 0 = off, 1 = on */
LORA_PARAMETER_BOOSTED_GAIN,
/** Carrier frequency in Hz */
LORA_PARAMETER_FREQUENCY,
/** Bandwidth in Hz */
LORA_PARAMETER_BANDWIDTH,
/** LoRa spreading factor (7-12) */
LORA_PARAMETER_SPREADING_FACTOR,
/** LoRa coding rate denominator (5-8 for 4/5 to 4/8) */
LORA_PARAMETER_CODING_RATE,
/**
* LoRa sync word (0x00-0xFF). Distinguishes otherwise-identical networks: a receiver
* only accepts packets whose sync word matches. Conventionally 0x12 for private
* networks and 0x34 for public/LoRaWAN. LoRa modulation only.
*/
LORA_PARAMETER_SYNC_WORD,
/** Preamble length in symbols (LoRa) or bits (FSK) */
LORA_PARAMETER_PREAMBLE_LENGTH,
/** FSK frequency deviation from the carrier in Hz */
LORA_PARAMETER_FREQUENCY_DEVIATION,
/** FSK bit rate in bits per second */
LORA_PARAMETER_DATA_RATE,
/** LR-FHSS grid spacing: 0 = 25 kHz (wide), 1 = 3.9 kHz (narrow) */
LORA_PARAMETER_NARROW_GRID,
/**
* PA over-current protection limit in mA. Fail-safe: a low limit caps the current the
* PA can push into a bad or disconnected antenna, but also caps the achievable output
* power. Drivers keep a conservative default; a board-aware consumer that knows its
* antenna and PA can raise it to reach full output power.
*/
LORA_PARAMETER_CURRENT_LIMIT,
};
enum LoraRadioState {
LORA_RADIO_STATE_OFF,
LORA_RADIO_STATE_ON_PENDING,
LORA_RADIO_STATE_ON,
LORA_RADIO_STATE_OFF_PENDING,
LORA_RADIO_STATE_ERROR,
};
/** Identifies a queued transmission. Unique per device until it wraps around. */
typedef int32_t LoraTxId;
enum LoraTransmissionState {
/** Accepted into the TX queue */
LORA_TRANSMISSION_STATE_QUEUED,
/** Handed to the modem, waiting for TX-done */
LORA_TRANSMISSION_STATE_TRANSMIT_PENDING,
/** TX-done confirmed by the modem */
LORA_TRANSMISSION_STATE_TRANSMITTED,
/** No TX-done within the driver's timeout */
LORA_TRANSMISSION_STATE_TIMEOUT,
/** The modem rejected the transmission */
LORA_TRANSMISSION_STATE_ERROR,
};
struct LoraRxPacket {
/** Packet payload. Only valid for the duration of the RX callback. */
const uint8_t* data;
size_t length;
/** Received signal strength in dBm */
float rssi;
/** Signal-to-noise ratio in dB */
float snr;
};
/**
* Callbacks are invoked without any driver lock held, either from the driver's radio
* thread (RX, TX progress, state) or from the thread calling transmit()/set_enabled()
* (the QUEUED TX event and enable/disable state changes). Taking consumer locks in a
* callback is therefore safe, but keep callbacks short: RX processing stalls while
* they run. After remove_*_callback returns, a callback that was already in flight
* may still complete once — disable the radio before destroying callback context.
*/
typedef void (*LoraStateCallback)(struct Device* device, void* context, enum LoraRadioState state);
typedef void (*LoraRxCallback)(struct Device* device, void* context, const struct LoraRxPacket* packet);
typedef void (*LoraTxCallback)(struct Device* device, void* context, LoraTxId id, enum LoraTransmissionState state);
struct LoraApi {
/**
* Get the radio state of the device.
* @param[in] device the lora device
* @param[out] state the radio state
* @return ERROR_NONE on success
*/
error_t (*get_radio_state)(struct Device* device, enum LoraRadioState* state);
/**
* Turn the radio on or off. Requires a modulation to be set before enabling.
* Turning on is asynchronous: observe the radio state to know when it's up.
* @param[in] device the lora device
* @param[in] enabled true to turn the radio on
* @return ERROR_NONE on success
* @retval ERROR_INVALID_STATE when enabling without a modulation set
*/
error_t (*set_enabled)(struct Device* device, bool enabled);
/**
* Set the modulation scheme. Only allowed while the radio is off.
* @param[in] device the lora device
* @param[in] modulation the modulation scheme
* @return ERROR_NONE on success
* @retval ERROR_INVALID_STATE when the radio is on or turning on
* @retval ERROR_NOT_SUPPORTED when the device supports neither TX nor RX for this modulation
*/
error_t (*set_modulation)(struct Device* device, enum LoraModulation modulation);
/**
* Get the current modulation scheme.
* @param[in] device the lora device
* @param[out] modulation the modulation scheme
* @return ERROR_NONE on success
*/
error_t (*get_modulation)(struct Device* device, enum LoraModulation* modulation);
/**
* @param[in] device the lora device
* @param[in] modulation the modulation scheme
* @return true when the device can transmit with the given modulation
*/
bool (*can_transmit)(struct Device* device, enum LoraModulation modulation);
/**
* @param[in] device the lora device
* @param[in] modulation the modulation scheme
* @return true when the device can receive with the given modulation
*/
bool (*can_receive)(struct Device* device, enum LoraModulation modulation);
/**
* Set a radio parameter. See LoraParameter for units.
* Parameters apply to the current modulation and take effect the next time the radio turns on.
* @param[in] device the lora device
* @param[in] parameter the parameter to set
* @param[in] value the value to set
* @return ERROR_NONE on success
* @retval ERROR_NOT_SUPPORTED when the parameter doesn't apply to the device or modulation
* @retval ERROR_OUT_OF_RANGE when the value is invalid for the parameter
*/
error_t (*set_parameter)(struct Device* device, enum LoraParameter parameter, int32_t value);
/**
* Get a radio parameter. See LoraParameter for units.
* @param[in] device the lora device
* @param[in] parameter the parameter to get
* @param[out] value the current value
* @return ERROR_NONE on success
* @retval ERROR_NOT_SUPPORTED when the parameter doesn't apply to the device or modulation
*/
error_t (*get_parameter)(struct Device* device, enum LoraParameter parameter, int32_t* value);
/**
* Queue a packet for transmission. The data is copied.
* Progress is reported through the TX callbacks, starting with QUEUED.
* @param[in] device the lora device
* @param[in] data the packet payload
* @param[in] length the payload length in bytes
* @param[out] id the id assigned to this transmission (optional, can be NULL)
* @return ERROR_NONE on success
*/
error_t (*transmit)(struct Device* device, const uint8_t* data, size_t length, LoraTxId* id);
/**
* Add a callback for received packets.
* @param[in] device the lora device
* @param[in] callback_context the context to pass to the callback
* @param[in] callback the callback function
* @return ERROR_NONE on success
*/
error_t (*add_rx_callback)(struct Device* device, void* callback_context, LoraRxCallback callback);
/**
* Remove a callback for received packets.
* @param[in] device the lora device
* @param[in] callback the callback function
* @return ERROR_NONE on success
*/
error_t (*remove_rx_callback)(struct Device* device, LoraRxCallback callback);
/**
* Add a callback for radio state changes.
* @param[in] device the lora device
* @param[in] callback_context the context to pass to the callback
* @param[in] callback the callback function
* @return ERROR_NONE on success
*/
error_t (*add_state_callback)(struct Device* device, void* callback_context, LoraStateCallback callback);
/**
* Remove a callback for radio state changes.
* @param[in] device the lora device
* @param[in] callback the callback function
* @return ERROR_NONE on success
*/
error_t (*remove_state_callback)(struct Device* device, LoraStateCallback callback);
/**
* Add a callback for transmission progress.
* @param[in] device the lora device
* @param[in] callback_context the context to pass to the callback
* @param[in] callback the callback function
* @return ERROR_NONE on success
*/
error_t (*add_tx_callback)(struct Device* device, void* callback_context, LoraTxCallback callback);
/**
* Remove a callback for transmission progress.
* @param[in] device the lora device
* @param[in] callback the callback function
* @return ERROR_NONE on success
*/
error_t (*remove_tx_callback)(struct Device* device, LoraTxCallback callback);
};
extern const struct DeviceType LORA_TYPE;
/** @return the first registered lora device, regardless of started state, or NULL if none exists */
struct Device* lora_find_first_registered_device(void);
error_t lora_get_radio_state(struct Device* device, enum LoraRadioState* state);
error_t lora_set_enabled(struct Device* device, bool enabled);
error_t lora_set_modulation(struct Device* device, enum LoraModulation modulation);
error_t lora_get_modulation(struct Device* device, enum LoraModulation* modulation);
bool lora_can_transmit(struct Device* device, enum LoraModulation modulation);
bool lora_can_receive(struct Device* device, enum LoraModulation modulation);
error_t lora_set_parameter(struct Device* device, enum LoraParameter parameter, int32_t value);
error_t lora_get_parameter(struct Device* device, enum LoraParameter parameter, int32_t* value);
error_t lora_transmit(struct Device* device, const uint8_t* data, size_t length, LoraTxId* id);
error_t lora_add_rx_callback(struct Device* device, void* callback_context, LoraRxCallback callback);
error_t lora_remove_rx_callback(struct Device* device, LoraRxCallback callback);
error_t lora_add_state_callback(struct Device* device, void* callback_context, LoraStateCallback callback);
error_t lora_remove_state_callback(struct Device* device, LoraStateCallback callback);
error_t lora_add_tx_callback(struct Device* device, void* callback_context, LoraTxCallback callback);
error_t lora_remove_tx_callback(struct Device* device, LoraTxCallback callback);
#ifdef __cplusplus
}
#endif