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authorLinus Torvalds <torvalds@linux-foundation.org>2024-01-13 01:59:50 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2024-01-13 01:59:50 +0300
commit42bff4d0f9b9c8b669c5cef25c5116f41eb45c6b (patch)
treefe9cefffc83c2e8cb4afe8d5fbfa632691dc3e91 /drivers/media
parentfef018d8199661962b5fc0f0d1501caa54b2b533 (diff)
parent7afc0e7f681e6efd6b826f003fc14c17b5093643 (diff)
downloadlinux-42bff4d0f9b9c8b669c5cef25c5116f41eb45c6b.tar.xz
Merge tag 'pwm/for-6.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/thierry.reding/linux-pwm
Pull pwm updates from Thierry Reding: "This contains a bunch of cleanups and simplifications across the board, as well as a number of small fixes. Perhaps the most notable change here is the addition of an API that allows PWMs to be used in atomic contexts, which is useful when time- critical operations are involved, such as using a PWM to generate IR signals. Finally, I have decided to step down as PWM subsystem maintainer. Due to other responsibilities I have lately not been able to find the time that the subsystem deserves and Uwe, who has been helping out a lot for the past few years and has many things planned for the future, has kindly volunteered to take over. I have no doubt that he will be a suitable replacement" * tag 'pwm/for-6.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/thierry.reding/linux-pwm: (44 commits) MAINTAINERS: pwm: Thierry steps down, Uwe takes over pwm: linux/pwm.h: fix Excess kernel-doc description warning pwm: Add pwm_apply_state() compatibility stub pwm: cros-ec: Drop documentation for dropped struct member pwm: Drop two unused API functions pwm: lpc18xx-sct: Don't modify the cached period of other PWM outputs pwm: meson: Simplify using dev_err_probe() pwm: stmpe: Silence duplicate error messages pwm: Reduce number of pointer dereferences in pwm_device_request() pwm: crc: Use consistent variable naming for driver data pwm: omap-dmtimer: Drop locking dt-bindings: pwm: ti,pwm-omap-dmtimer: Update binding for yaml media: pwm-ir-tx: Trigger edges from hrtimer interrupt context pwm: bcm2835: Allow PWM driver to be used in atomic context pwm: Make it possible to apply PWM changes in atomic context pwm: renesas: Remove unused include pwm: Replace ENOTSUPP with EOPNOTSUPP pwm: Rename pwm_apply_state() to pwm_apply_might_sleep() pwm: Stop referencing pwm->chip pwm: Update kernel doc for struct pwm_chip ...
Diffstat (limited to 'drivers/media')
-rw-r--r--drivers/media/rc/pwm-ir-tx.c87
1 files changed, 80 insertions, 7 deletions
diff --git a/drivers/media/rc/pwm-ir-tx.c b/drivers/media/rc/pwm-ir-tx.c
index c5f37c03af9c..fe368aebbc13 100644
--- a/drivers/media/rc/pwm-ir-tx.c
+++ b/drivers/media/rc/pwm-ir-tx.c
@@ -10,6 +10,8 @@
#include <linux/slab.h>
#include <linux/of.h>
#include <linux/platform_device.h>
+#include <linux/hrtimer.h>
+#include <linux/completion.h>
#include <media/rc-core.h>
#define DRIVER_NAME "pwm-ir-tx"
@@ -17,8 +19,14 @@
struct pwm_ir {
struct pwm_device *pwm;
- unsigned int carrier;
- unsigned int duty_cycle;
+ struct hrtimer timer;
+ struct completion tx_done;
+ struct pwm_state *state;
+ u32 carrier;
+ u32 duty_cycle;
+ const unsigned int *txbuf;
+ unsigned int txbuf_len;
+ unsigned int txbuf_index;
};
static const struct of_device_id pwm_ir_of_match[] = {
@@ -49,8 +57,8 @@ static int pwm_ir_set_carrier(struct rc_dev *dev, u32 carrier)
return 0;
}
-static int pwm_ir_tx(struct rc_dev *dev, unsigned int *txbuf,
- unsigned int count)
+static int pwm_ir_tx_sleep(struct rc_dev *dev, unsigned int *txbuf,
+ unsigned int count)
{
struct pwm_ir *pwm_ir = dev->priv;
struct pwm_device *pwm = pwm_ir->pwm;
@@ -68,7 +76,7 @@ static int pwm_ir_tx(struct rc_dev *dev, unsigned int *txbuf,
for (i = 0; i < count; i++) {
state.enabled = !(i % 2);
- pwm_apply_state(pwm, &state);
+ pwm_apply_might_sleep(pwm, &state);
edge = ktime_add_us(edge, txbuf[i]);
delta = ktime_us_delta(edge, ktime_get());
@@ -77,11 +85,67 @@ static int pwm_ir_tx(struct rc_dev *dev, unsigned int *txbuf,
}
state.enabled = false;
- pwm_apply_state(pwm, &state);
+ pwm_apply_might_sleep(pwm, &state);
return count;
}
+static int pwm_ir_tx_atomic(struct rc_dev *dev, unsigned int *txbuf,
+ unsigned int count)
+{
+ struct pwm_ir *pwm_ir = dev->priv;
+ struct pwm_device *pwm = pwm_ir->pwm;
+ struct pwm_state state;
+
+ pwm_init_state(pwm, &state);
+
+ state.period = DIV_ROUND_CLOSEST(NSEC_PER_SEC, pwm_ir->carrier);
+ pwm_set_relative_duty_cycle(&state, pwm_ir->duty_cycle, 100);
+
+ pwm_ir->txbuf = txbuf;
+ pwm_ir->txbuf_len = count;
+ pwm_ir->txbuf_index = 0;
+ pwm_ir->state = &state;
+
+ hrtimer_start(&pwm_ir->timer, 0, HRTIMER_MODE_REL);
+
+ wait_for_completion(&pwm_ir->tx_done);
+
+ return count;
+}
+
+static enum hrtimer_restart pwm_ir_timer(struct hrtimer *timer)
+{
+ struct pwm_ir *pwm_ir = container_of(timer, struct pwm_ir, timer);
+ ktime_t now;
+
+ /*
+ * If we happen to hit an odd latency spike, loop through the
+ * pulses until we catch up.
+ */
+ do {
+ u64 ns;
+
+ pwm_ir->state->enabled = !(pwm_ir->txbuf_index % 2);
+ pwm_apply_atomic(pwm_ir->pwm, pwm_ir->state);
+
+ if (pwm_ir->txbuf_index >= pwm_ir->txbuf_len) {
+ complete(&pwm_ir->tx_done);
+
+ return HRTIMER_NORESTART;
+ }
+
+ ns = US_TO_NS(pwm_ir->txbuf[pwm_ir->txbuf_index]);
+ hrtimer_add_expires_ns(timer, ns);
+
+ pwm_ir->txbuf_index++;
+
+ now = timer->base->get_time();
+ } while (hrtimer_get_expires_tv64(timer) < now);
+
+ return HRTIMER_RESTART;
+}
+
static int pwm_ir_probe(struct platform_device *pdev)
{
struct pwm_ir *pwm_ir;
@@ -103,10 +167,19 @@ static int pwm_ir_probe(struct platform_device *pdev)
if (!rcdev)
return -ENOMEM;
+ if (pwm_might_sleep(pwm_ir->pwm)) {
+ dev_info(&pdev->dev, "TX will not be accurate as PWM device might sleep\n");
+ rcdev->tx_ir = pwm_ir_tx_sleep;
+ } else {
+ init_completion(&pwm_ir->tx_done);
+ hrtimer_init(&pwm_ir->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
+ pwm_ir->timer.function = pwm_ir_timer;
+ rcdev->tx_ir = pwm_ir_tx_atomic;
+ }
+
rcdev->priv = pwm_ir;
rcdev->driver_name = DRIVER_NAME;
rcdev->device_name = DEVICE_NAME;
- rcdev->tx_ir = pwm_ir_tx;
rcdev->s_tx_duty_cycle = pwm_ir_set_duty_cycle;
rcdev->s_tx_carrier = pwm_ir_set_carrier;