summaryrefslogtreecommitdiffstats
path: root/drivers/media/rc/ir-sharp-decoder.c
diff options
context:
space:
mode:
authorPaul E. McKenney <paulmck@kernel.org>2026-08-14 15:43:51 -0700
committerPaul E. McKenney <paulmck@kernel.org>2026-08-14 15:43:51 -0700
commit9cc63f8bcd560c760d0b12e15bba8f81c86237cf (patch)
tree3b5269b1bcf6714171754946367c51e0590f64da /drivers/media/rc/ir-sharp-decoder.c
downloadlinux-stable-9cc63f8bcd560c760d0b12e15bba8f81c86237cf.tar.gz
linux-stable-9cc63f8bcd560c760d0b12e15bba8f81c86237cf.zip
Merge branches 'expcb.2026.07.24a', 'misc.2026.07.30a', 'rcu-tasks.2026.07.30a', 'srcu.2026.08.11a' and 'torture.2026.08.14a' into HEADgrafted
Changes: Make expedited grace periods expedite normal RCU callbacks Miscellaneous fixes: * Improve diagnostic output with character task states. * Mark accesses to inform KCSAN of concurrency design. * Move from kmalloc() to kmalloc_obj(). * Documentation updates. * Improve handling of RCU deferred quiescent states. * Clean up unused function arguments and structure fields. * Reduce show_rcu_gp_kthreads() stack space. Tasks RCU updates: * Clean up after SRCU re-implementation of Tasks Trace RCU. * Mark accesses to inform KCSAN of concurrency design. * Add ->lazy_timer status to diagnostic output. * Remove an unnecessary memory barrier. * Fix a data race, courtesy of KCSAN. * Documentation updates. * Convert cond_resched_tasks_rcu_qs() from macro to static inline function. SRCU updates: * Add Rust helpers for SRCU. * Avoid losing queued work at cleanup_srcu_struct() time. Torture-test updates: * Preparation work for immediate RCU priority deboosting. * Test RCU readers from real interrupt handlers (as opposed to softirq). * Simplify code through use of cpumask_next_wrap(). * Improve diagnostic output with character task states. * Add rcutorture.nwriters parameter to allow lightweight stall testing, and rcutorture.stall_only to make doing so easier. * Test an RCU Tasks Trace grace period implying an RCU grace period. * Make RCU Tasks Trace torturing track reader batches. * Fix a data race, courtesy of KCSAN. * Plug a shuffle_tmp_mask memory leak on kthread spawn failure.
Diffstat (limited to 'drivers/media/rc/ir-sharp-decoder.c')
-rw-r--r--drivers/media/rc/ir-sharp-decoder.c244
1 files changed, 244 insertions, 0 deletions
diff --git a/drivers/media/rc/ir-sharp-decoder.c b/drivers/media/rc/ir-sharp-decoder.c
new file mode 100644
index 000000000..3311099cb
--- /dev/null
+++ b/drivers/media/rc/ir-sharp-decoder.c
@@ -0,0 +1,244 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* ir-sharp-decoder.c - handle Sharp IR Pulse/Space protocol
+ *
+ * Copyright (C) 2013-2014 Imagination Technologies Ltd.
+ *
+ * Based on NEC decoder:
+ * Copyright (C) 2010 by Mauro Carvalho Chehab
+ */
+
+#include <linux/bitrev.h>
+#include <linux/module.h>
+#include "rc-core-priv.h"
+
+#define SHARP_NBITS 15
+#define SHARP_UNIT 40 /* us */
+#define SHARP_BIT_PULSE (8 * SHARP_UNIT) /* 320us */
+#define SHARP_BIT_0_PERIOD (25 * SHARP_UNIT) /* 1ms (680us space) */
+#define SHARP_BIT_1_PERIOD (50 * SHARP_UNIT) /* 2ms (1680us space) */
+#define SHARP_BIT_0_SPACE (17 * SHARP_UNIT) /* 680us space */
+#define SHARP_BIT_1_SPACE (42 * SHARP_UNIT) /* 1680us space */
+#define SHARP_ECHO_SPACE (1000 * SHARP_UNIT) /* 40 ms */
+#define SHARP_TRAILER_SPACE (125 * SHARP_UNIT) /* 5 ms (even longer) */
+
+enum sharp_state {
+ STATE_INACTIVE,
+ STATE_BIT_PULSE,
+ STATE_BIT_SPACE,
+ STATE_TRAILER_PULSE,
+ STATE_ECHO_SPACE,
+ STATE_TRAILER_SPACE,
+};
+
+/**
+ * ir_sharp_decode() - Decode one Sharp 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_sharp_decode(struct rc_dev *dev, struct ir_raw_event ev)
+{
+ struct sharp_dec *data = &dev->raw->sharp;
+ u32 msg, echo, address, command, scancode;
+
+ if (!is_timing_event(ev)) {
+ if (ev.overflow)
+ data->state = STATE_INACTIVE;
+ return 0;
+ }
+
+ dev_dbg(&dev->dev, "Sharp 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, SHARP_BIT_PULSE,
+ SHARP_BIT_PULSE / 2))
+ break;
+
+ data->count = 0;
+ data->pulse_len = ev.duration;
+ data->state = STATE_BIT_SPACE;
+ return 0;
+
+ case STATE_BIT_PULSE:
+ if (!ev.pulse)
+ break;
+
+ if (!eq_margin(ev.duration, SHARP_BIT_PULSE,
+ SHARP_BIT_PULSE / 2))
+ break;
+
+ data->pulse_len = ev.duration;
+ data->state = STATE_BIT_SPACE;
+ return 0;
+
+ case STATE_BIT_SPACE:
+ if (ev.pulse)
+ break;
+
+ data->bits <<= 1;
+ if (eq_margin(data->pulse_len + ev.duration, SHARP_BIT_1_PERIOD,
+ SHARP_BIT_PULSE * 2))
+ data->bits |= 1;
+ else if (!eq_margin(data->pulse_len + ev.duration,
+ SHARP_BIT_0_PERIOD, SHARP_BIT_PULSE * 2))
+ break;
+ data->count++;
+
+ if (data->count == SHARP_NBITS ||
+ data->count == SHARP_NBITS * 2)
+ 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, SHARP_BIT_PULSE,
+ SHARP_BIT_PULSE / 2))
+ break;
+
+ if (data->count == SHARP_NBITS) {
+ /* exp,chk bits should be 1,0 */
+ if ((data->bits & 0x3) != 0x2 &&
+ /* DENON variant, both chk bits 0 */
+ (data->bits & 0x3) != 0x0)
+ break;
+ data->state = STATE_ECHO_SPACE;
+ } else {
+ data->state = STATE_TRAILER_SPACE;
+ }
+ return 0;
+
+ case STATE_ECHO_SPACE:
+ if (ev.pulse)
+ break;
+
+ if (!eq_margin(ev.duration, SHARP_ECHO_SPACE,
+ SHARP_ECHO_SPACE / 4))
+ break;
+
+ data->state = STATE_BIT_PULSE;
+
+ return 0;
+
+ case STATE_TRAILER_SPACE:
+ if (ev.pulse)
+ break;
+
+ if (!geq_margin(ev.duration, SHARP_TRAILER_SPACE,
+ SHARP_BIT_PULSE / 2))
+ break;
+
+ /* Validate - command, ext, chk should be inverted in 2nd */
+ msg = (data->bits >> 15) & 0x7fff;
+ echo = data->bits & 0x7fff;
+ if ((msg ^ echo) != 0x3ff) {
+ dev_dbg(&dev->dev,
+ "Sharp checksum error: received 0x%04x, 0x%04x\n",
+ msg, echo);
+ break;
+ }
+
+ address = bitrev8((msg >> 7) & 0xf8);
+ command = bitrev8((msg >> 2) & 0xff);
+
+ scancode = address << 8 | command;
+ dev_dbg(&dev->dev, "Sharp scancode 0x%04x\n", scancode);
+
+ rc_keydown(dev, RC_PROTO_SHARP, scancode, 0);
+ data->state = STATE_INACTIVE;
+ return 0;
+ }
+
+ dev_dbg(&dev->dev, "Sharp 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;
+}
+
+static const struct ir_raw_timings_pd ir_sharp_timings = {
+ .header_pulse = 0,
+ .header_space = 0,
+ .bit_pulse = SHARP_BIT_PULSE,
+ .bit_space[0] = SHARP_BIT_0_SPACE,
+ .bit_space[1] = SHARP_BIT_1_SPACE,
+ .trailer_pulse = SHARP_BIT_PULSE,
+ .trailer_space = SHARP_ECHO_SPACE,
+ .msb_first = 1,
+};
+
+/**
+ * ir_sharp_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_sharp_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;
+
+ raw = (((bitrev8(scancode >> 8) >> 3) << 8) & 0x1f00) |
+ bitrev8(scancode);
+ ret = ir_raw_gen_pd(&e, max, &ir_sharp_timings, SHARP_NBITS,
+ (raw << 2) | 2);
+ if (ret < 0)
+ return ret;
+
+ max -= ret;
+
+ raw = (((bitrev8(scancode >> 8) >> 3) << 8) & 0x1f00) |
+ bitrev8(~scancode);
+ ret = ir_raw_gen_pd(&e, max, &ir_sharp_timings, SHARP_NBITS,
+ (raw << 2) | 1);
+ if (ret < 0)
+ return ret;
+
+ return e - events;
+}
+
+static struct ir_raw_handler sharp_handler = {
+ .protocols = RC_PROTO_BIT_SHARP,
+ .decode = ir_sharp_decode,
+ .encode = ir_sharp_encode,
+ .carrier = 38000,
+ .min_timeout = SHARP_ECHO_SPACE + SHARP_ECHO_SPACE / 4,
+};
+
+static int __init ir_sharp_decode_init(void)
+{
+ ir_raw_handler_register(&sharp_handler);
+
+ pr_info("IR Sharp protocol handler initialized\n");
+ return 0;
+}
+
+static void __exit ir_sharp_decode_exit(void)
+{
+ ir_raw_handler_unregister(&sharp_handler);
+}
+
+module_init(ir_sharp_decode_init);
+module_exit(ir_sharp_decode_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("James Hogan <jhogan@kernel.org>");
+MODULE_DESCRIPTION("Sharp IR protocol decoder");