This makes the generated IR much more precise. Before this change, the
driver is unreliable and many users opted to use gpio-ir-tx instead.
Signed-off-by: Sean Young <[email protected]>
---
drivers/media/rc/pwm-ir-tx.c | 79 ++++++++++++++++++++++++++++++++++--
1 file changed, 76 insertions(+), 3 deletions(-)
diff --git a/drivers/media/rc/pwm-ir-tx.c b/drivers/media/rc/pwm-ir-tx.c
index cf51e27609759..168f0b3539fa0 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[] = {
@@ -82,6 +90,62 @@ static int pwm_ir_tx(struct rc_dev *dev, unsigned int *txbuf,
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;
+ } 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;
--
2.43.0
On Mon, Dec 11, 2023 at 08:24:55AM +0000, Sean Young wrote:
> This makes the generated IR much more precise. Before this change, the
> driver is unreliable and many users opted to use gpio-ir-tx instead.
>
> Signed-off-by: Sean Young <[email protected]>
> ---
> drivers/media/rc/pwm-ir-tx.c | 79 ++++++++++++++++++++++++++++++++++--
> 1 file changed, 76 insertions(+), 3 deletions(-)
Hi Mauro,
are you okay with me picking this up into the PWM tree?
Thanks,
Thierry