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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2026-08-23 13:28:57 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2026-08-23 13:28:57 -0700 |
| commit | 4352b8aee98005853aa63f57d6377282de17a33f (patch) | |
| tree | 27614d7a9ef05c32d089004e104364ce42324837 /drivers/media/rc/ir-nec-decoder.c | |
| download | linux-stable-4352b8aee98005853aa63f57d6377282de17a33f.tar.gz linux-stable-4352b8aee98005853aa63f57d6377282de17a33f.zip | |
Merge tag 'i3c/for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linuxgrafted
Pull I3C updates from Alexandre Belloni:
"A new driver this cycle, for the AMD AXI I3C controller.
There are also new features such as IBI wakeup support, SETAASA device
discovery and ACPI support for the the DAA methods, meaning we can now
communicate with the SPD devices on DDR5 modules.
New driver:
- AMD AXI I3C master controller
Subsystem:
- I3C Common Command Code (CCC) handling improvements, especially
around GET CCCs
- SETAASA device discovery support
- ACPI support for all existing DAA methods like SETDASA, SETNEWDA as
well as I2C devices on I3C bus
- IBI-based wakeup support
Drivers:
- dw: SETAASA support
- mipi-i3c-hci: advertise IBI wakeup capability, AMD_PT I3C
controller support, PIO queue management support for HCI v1.2
- renesas: improve suspend to RAM support, add runtime PM support"
* tag 'i3c/for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linux: (70 commits)
i3c: dw: reduce do_daa time if there's no client
i3c: mipi-i3c-hci: Add support for AMD_PT I3C controller
i3c: mipi-i3c-hci: Add PIO queue management support for HCI v1.2
i3c: mipi-i3c-hci: Fix missing STAT_IBI_STATUS_THLD in PIO mode
i3c: dw: rename "pclk" to "apb" to match dt-binding
i3c: dw: make struct dw_i3c_cmd smaller
i3c: dw: use COMMAND_PORT_TRANSFER_ARG instead of hardcoding
i3c: renesas: Don't register devices when ENTDAA times out
i3c: master: dw-i3c-master: fix OD timing for first broadcast
i3c: mipi-i3c-hci: Advertise IBI wakeup capability
i3c: mipi-i3c-hci: Factor out i3c_hci_sysdev()
i3c: mipi-i3c-hci-pci: Propagate I3C wakeup requirements to PCI
i3c: master: Reject IBI requests from non-IBI-capable devices
i3c: master: Add helper to query bus wakeup requirements
i3c: master: Report wakeup events for IBIs
i3c: master: Support IBI-based wakeup capability
i3c: master: Fix potential UAF in i3c_device_match()
i3c: master: Fix potential UAF in i3c_device_uevent()
i3c: Make dev->desc locking assumptions explicit
i3c: master: Fix use-after-free of master->this
...
Diffstat (limited to 'drivers/media/rc/ir-nec-decoder.c')
| -rw-r--r-- | drivers/media/rc/ir-nec-decoder.c | 278 |
1 files changed, 278 insertions, 0 deletions
diff --git a/drivers/media/rc/ir-nec-decoder.c b/drivers/media/rc/ir-nec-decoder.c new file mode 100644 index 000000000..37b99432a --- /dev/null +++ b/drivers/media/rc/ir-nec-decoder.c @@ -0,0 +1,278 @@ +// SPDX-License-Identifier: GPL-2.0 +// ir-nec-decoder.c - handle NEC IR Pulse/Space protocol +// +// Copyright (C) 2010 by Mauro Carvalho Chehab + +#include <linux/bitrev.h> +#include <linux/module.h> +#include "rc-core-priv.h" + +#define NEC_NBITS 32 +#define NEC_UNIT 563 /* us */ +#define NEC_HEADER_PULSE (16 * NEC_UNIT) +#define NECX_HEADER_PULSE (8 * NEC_UNIT) /* Less common NEC variant */ +#define NEC_HEADER_SPACE (8 * NEC_UNIT) +#define NEC_REPEAT_SPACE (4 * NEC_UNIT) +#define NEC_BIT_PULSE (1 * NEC_UNIT) +#define NEC_BIT_0_SPACE (1 * NEC_UNIT) +#define NEC_BIT_1_SPACE (3 * NEC_UNIT) +#define NEC_TRAILER_PULSE (1 * NEC_UNIT) +#define NEC_TRAILER_SPACE (10 * NEC_UNIT) /* even longer in reality */ +#define NECX_REPEAT_BITS 1 + +enum nec_state { + STATE_INACTIVE, + STATE_HEADER_SPACE, + STATE_BIT_PULSE, + STATE_BIT_SPACE, + STATE_TRAILER_PULSE, + STATE_TRAILER_SPACE, +}; + +/** + * ir_nec_decode() - Decode one NEC pulse or space + * @dev: the struct rc_dev descriptor of the device + * @ev: the struct ir_raw_event descriptor of the pulse/space + * + * This function returns -EINVAL if the pulse violates the state machine + */ +static int ir_nec_decode(struct rc_dev *dev, struct ir_raw_event ev) +{ + struct nec_dec *data = &dev->raw->nec; + u32 scancode; + enum rc_proto rc_proto; + u8 address, not_address, command, not_command; + + if (!is_timing_event(ev)) { + if (ev.overflow) + data->state = STATE_INACTIVE; + return 0; + } + + dev_dbg(&dev->dev, "NEC decode started at state %d (%uus %s)\n", + data->state, ev.duration, TO_STR(ev.pulse)); + + switch (data->state) { + + case STATE_INACTIVE: + if (!ev.pulse) + break; + + if (eq_margin(ev.duration, NEC_HEADER_PULSE, NEC_UNIT * 2)) { + data->is_nec_x = false; + data->necx_repeat = false; + } else if (eq_margin(ev.duration, NECX_HEADER_PULSE, NEC_UNIT / 2)) + data->is_nec_x = true; + else + break; + + data->count = 0; + data->state = STATE_HEADER_SPACE; + return 0; + + case STATE_HEADER_SPACE: + if (ev.pulse) + break; + + if (eq_margin(ev.duration, NEC_HEADER_SPACE, NEC_UNIT)) { + data->state = STATE_BIT_PULSE; + return 0; + } else if (eq_margin(ev.duration, NEC_REPEAT_SPACE, NEC_UNIT / 2)) { + data->state = STATE_TRAILER_PULSE; + return 0; + } + + break; + + case STATE_BIT_PULSE: + if (!ev.pulse) + break; + + if (!eq_margin(ev.duration, NEC_BIT_PULSE, NEC_UNIT / 2)) + break; + + data->state = STATE_BIT_SPACE; + return 0; + + case STATE_BIT_SPACE: + if (ev.pulse) + break; + + if (data->necx_repeat && data->count == NECX_REPEAT_BITS && + geq_margin(ev.duration, NEC_TRAILER_SPACE, NEC_UNIT / 2)) { + dev_dbg(&dev->dev, "Repeat last key\n"); + rc_repeat(dev); + data->state = STATE_INACTIVE; + return 0; + } else if (data->count > NECX_REPEAT_BITS) + data->necx_repeat = false; + + data->bits <<= 1; + if (eq_margin(ev.duration, NEC_BIT_1_SPACE, NEC_UNIT / 2)) + data->bits |= 1; + else if (!eq_margin(ev.duration, NEC_BIT_0_SPACE, NEC_UNIT / 2)) + break; + data->count++; + + if (data->count == NEC_NBITS) + data->state = STATE_TRAILER_PULSE; + else + data->state = STATE_BIT_PULSE; + + return 0; + + case STATE_TRAILER_PULSE: + if (!ev.pulse) + break; + + if (!eq_margin(ev.duration, NEC_TRAILER_PULSE, NEC_UNIT / 2)) + break; + + data->state = STATE_TRAILER_SPACE; + return 0; + + case STATE_TRAILER_SPACE: + if (ev.pulse) + break; + + if (!geq_margin(ev.duration, NEC_TRAILER_SPACE, NEC_UNIT / 2)) + break; + + if (data->count == NEC_NBITS) { + address = bitrev8((data->bits >> 24) & 0xff); + not_address = bitrev8((data->bits >> 16) & 0xff); + command = bitrev8((data->bits >> 8) & 0xff); + not_command = bitrev8((data->bits >> 0) & 0xff); + + scancode = ir_nec_bytes_to_scancode(address, + not_address, + command, + not_command, + &rc_proto); + + if (data->is_nec_x) + data->necx_repeat = true; + + rc_keydown(dev, rc_proto, scancode, 0); + } else { + rc_repeat(dev); + } + + data->state = STATE_INACTIVE; + return 0; + } + + dev_dbg(&dev->dev, "NEC decode failed at count %d state %d (%uus %s)\n", + data->count, data->state, ev.duration, TO_STR(ev.pulse)); + data->state = STATE_INACTIVE; + return -EINVAL; +} + +/** + * ir_nec_scancode_to_raw() - encode an NEC scancode ready for modulation. + * @protocol: specific protocol to use + * @scancode: a single NEC scancode. + */ +static u32 ir_nec_scancode_to_raw(enum rc_proto protocol, u32 scancode) +{ + unsigned int addr, addr_inv, data, data_inv; + + data = scancode & 0xff; + + if (protocol == RC_PROTO_NEC32) { + /* 32-bit NEC (used by Apple and TiVo remotes) */ + /* scan encoding: aaAAddDD */ + addr_inv = (scancode >> 24) & 0xff; + addr = (scancode >> 16) & 0xff; + data_inv = (scancode >> 8) & 0xff; + } else if (protocol == RC_PROTO_NECX) { + /* Extended NEC */ + /* scan encoding AAaaDD */ + addr = (scancode >> 16) & 0xff; + addr_inv = (scancode >> 8) & 0xff; + data_inv = data ^ 0xff; + } else { + /* Normal NEC */ + /* scan encoding: AADD */ + addr = (scancode >> 8) & 0xff; + addr_inv = addr ^ 0xff; + data_inv = data ^ 0xff; + } + + /* raw encoding: ddDDaaAA */ + return data_inv << 24 | + data << 16 | + addr_inv << 8 | + addr; +} + +static const struct ir_raw_timings_pd ir_nec_timings = { + .header_pulse = NEC_HEADER_PULSE, + .header_space = NEC_HEADER_SPACE, + .bit_pulse = NEC_BIT_PULSE, + .bit_space[0] = NEC_BIT_0_SPACE, + .bit_space[1] = NEC_BIT_1_SPACE, + .trailer_pulse = NEC_TRAILER_PULSE, + .trailer_space = NEC_TRAILER_SPACE, + .msb_first = 0, +}; + +/** + * ir_nec_encode() - Encode a scancode as a stream of raw events + * + * @protocol: protocol to encode + * @scancode: scancode to encode + * @events: array of raw ir events to write into + * @max: maximum size of @events + * + * Returns: The number of events written. + * -ENOBUFS if there isn't enough space in the array to fit the + * encoding. In this case all @max events will have been written. + */ +static int ir_nec_encode(enum rc_proto protocol, u32 scancode, + struct ir_raw_event *events, unsigned int max) +{ + struct ir_raw_event *e = events; + int ret; + u32 raw; + + /* Convert a NEC scancode to raw NEC data */ + raw = ir_nec_scancode_to_raw(protocol, scancode); + + /* Modulate the raw data using a pulse distance modulation */ + ret = ir_raw_gen_pd(&e, max, &ir_nec_timings, NEC_NBITS, raw); + if (ret < 0) + return ret; + + return e - events; +} + +static struct ir_raw_handler nec_handler = { + .protocols = RC_PROTO_BIT_NEC | RC_PROTO_BIT_NECX | + RC_PROTO_BIT_NEC32, + .decode = ir_nec_decode, + .encode = ir_nec_encode, + .carrier = 38000, + .min_timeout = NEC_TRAILER_SPACE, +}; + +static int __init ir_nec_decode_init(void) +{ + ir_raw_handler_register(&nec_handler); + + printk(KERN_INFO "IR NEC protocol handler initialized\n"); + return 0; +} + +static void __exit ir_nec_decode_exit(void) +{ + ir_raw_handler_unregister(&nec_handler); +} + +module_init(ir_nec_decode_init); +module_exit(ir_nec_decode_exit); + +MODULE_LICENSE("GPL v2"); +MODULE_AUTHOR("Mauro Carvalho Chehab"); +MODULE_AUTHOR("Red Hat Inc. (http://www.redhat.com)"); +MODULE_DESCRIPTION("NEC IR protocol decoder"); |
