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media: pwm-ir-tx: Trigger edges from hrtimer interrupt context
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 <sean@mess.org> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
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@ -10,6 +10,8 @@
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#include <linux/slab.h>
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#include <linux/of.h>
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#include <linux/platform_device.h>
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#include <linux/hrtimer.h>
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#include <linux/completion.h>
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#include <media/rc-core.h>
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#define DRIVER_NAME "pwm-ir-tx"
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@ -17,8 +19,14 @@
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struct pwm_ir {
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struct pwm_device *pwm;
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unsigned int carrier;
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unsigned int duty_cycle;
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struct hrtimer timer;
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struct completion tx_done;
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struct pwm_state *state;
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u32 carrier;
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u32 duty_cycle;
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const unsigned int *txbuf;
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unsigned int txbuf_len;
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unsigned int txbuf_index;
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};
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static const struct of_device_id pwm_ir_of_match[] = {
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@ -49,8 +57,8 @@ static int pwm_ir_set_carrier(struct rc_dev *dev, u32 carrier)
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return 0;
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}
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static int pwm_ir_tx(struct rc_dev *dev, unsigned int *txbuf,
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unsigned int count)
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static int pwm_ir_tx_sleep(struct rc_dev *dev, unsigned int *txbuf,
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unsigned int count)
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{
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struct pwm_ir *pwm_ir = dev->priv;
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struct pwm_device *pwm = pwm_ir->pwm;
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@ -82,6 +90,62 @@ static int pwm_ir_tx(struct rc_dev *dev, unsigned int *txbuf,
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return count;
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}
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static int pwm_ir_tx_atomic(struct rc_dev *dev, unsigned int *txbuf,
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unsigned int count)
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{
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struct pwm_ir *pwm_ir = dev->priv;
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struct pwm_device *pwm = pwm_ir->pwm;
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struct pwm_state state;
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pwm_init_state(pwm, &state);
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state.period = DIV_ROUND_CLOSEST(NSEC_PER_SEC, pwm_ir->carrier);
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pwm_set_relative_duty_cycle(&state, pwm_ir->duty_cycle, 100);
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pwm_ir->txbuf = txbuf;
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pwm_ir->txbuf_len = count;
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pwm_ir->txbuf_index = 0;
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pwm_ir->state = &state;
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hrtimer_start(&pwm_ir->timer, 0, HRTIMER_MODE_REL);
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wait_for_completion(&pwm_ir->tx_done);
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return count;
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}
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static enum hrtimer_restart pwm_ir_timer(struct hrtimer *timer)
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{
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struct pwm_ir *pwm_ir = container_of(timer, struct pwm_ir, timer);
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ktime_t now;
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/*
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* If we happen to hit an odd latency spike, loop through the
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* pulses until we catch up.
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*/
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do {
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u64 ns;
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pwm_ir->state->enabled = !(pwm_ir->txbuf_index % 2);
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pwm_apply_atomic(pwm_ir->pwm, pwm_ir->state);
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if (pwm_ir->txbuf_index >= pwm_ir->txbuf_len) {
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complete(&pwm_ir->tx_done);
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return HRTIMER_NORESTART;
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}
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ns = US_TO_NS(pwm_ir->txbuf[pwm_ir->txbuf_index]);
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hrtimer_add_expires_ns(timer, ns);
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pwm_ir->txbuf_index++;
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now = timer->base->get_time();
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} while (hrtimer_get_expires_tv64(timer) < now);
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return HRTIMER_RESTART;
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}
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static int pwm_ir_probe(struct platform_device *pdev)
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{
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struct pwm_ir *pwm_ir;
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@ -103,10 +167,19 @@ static int pwm_ir_probe(struct platform_device *pdev)
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if (!rcdev)
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return -ENOMEM;
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if (pwm_might_sleep(pwm_ir->pwm)) {
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dev_info(&pdev->dev, "TX will not be accurate as PWM device might sleep\n");
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rcdev->tx_ir = pwm_ir_tx_sleep;
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} else {
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init_completion(&pwm_ir->tx_done);
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hrtimer_init(&pwm_ir->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
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pwm_ir->timer.function = pwm_ir_timer;
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rcdev->tx_ir = pwm_ir_tx_atomic;
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}
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rcdev->priv = pwm_ir;
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rcdev->driver_name = DRIVER_NAME;
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rcdev->device_name = DEVICE_NAME;
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rcdev->tx_ir = pwm_ir_tx;
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rcdev->s_tx_duty_cycle = pwm_ir_set_duty_cycle;
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rcdev->s_tx_carrier = pwm_ir_set_carrier;
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