* [PATCH 2/2] media: gpio-ir-tx: allow transmission without carrier
2020-05-06 10:42 [PATCH 1/2] media: rc: improve precision of transmitted signal due to scheduling Sean Young
@ 2020-05-06 10:42 ` Sean Young
0 siblings, 0 replies; 2+ messages in thread
From: Sean Young @ 2020-05-06 10:42 UTC (permalink / raw)
To: linux-media
Some IR protocols do not use a carrier.
Signed-off-by: Sean Young <sean@mess.org>
---
drivers/media/rc/gpio-ir-tx.c | 56 +++++++++++++++++++++++++++++++----
1 file changed, 50 insertions(+), 6 deletions(-)
diff --git a/drivers/media/rc/gpio-ir-tx.c b/drivers/media/rc/gpio-ir-tx.c
index 66703989ae185..cd3f284b2f6d6 100644
--- a/drivers/media/rc/gpio-ir-tx.c
+++ b/drivers/media/rc/gpio-ir-tx.c
@@ -42,18 +42,51 @@ static int gpio_ir_tx_set_carrier(struct rc_dev *dev, u32 carrier)
{
struct gpio_ir *gpio_ir = dev->priv;
- if (!carrier)
- return -EINVAL;
-
gpio_ir->carrier = carrier;
return 0;
}
-static int gpio_ir_tx(struct rc_dev *dev, unsigned int *txbuf,
- unsigned int count)
+static void gpio_ir_tx_unmodulated(struct gpio_ir *gpio_ir, uint *txbuf,
+ uint count)
+{
+ unsigned long flags;
+ ktime_t edge;
+ /*
+ * delta should never exceed 0.5 seconds (IR_MAX_DURATION) and on
+ * m68k ndelay(s64) does not compile; so use s32 rather than s64.
+ */
+ s32 delta;
+ int i;
+
+ spin_lock_irqsave(&gpio_ir->lock, flags);
+
+ edge = ktime_get();
+
+ for (i = 0; i < count; i++) {
+ if (i % 2) {
+ // space
+ edge = ktime_add_us(edge, txbuf[i]);
+ delta = ktime_us_delta(edge, ktime_get());
+ if (delta > 0)
+ udelay(delta);
+ } else {
+ // pulse
+ gpiod_set_value(gpio_ir->gpio, 1);
+ edge = ktime_add_us(edge, txbuf[i]);
+ delta = ktime_us_delta(edge, ktime_get());
+ if (delta > 0)
+ udelay(delta);
+ gpiod_set_value(gpio_ir->gpio, 0);
+ }
+ }
+
+ spin_unlock_irqrestore(&gpio_ir->lock, flags);
+}
+
+static void gpio_ir_tx_modulated(struct gpio_ir *gpio_ir, uint *txbuf,
+ uint count)
{
- struct gpio_ir *gpio_ir = dev->priv;
unsigned long flags;
ktime_t edge;
/*
@@ -105,6 +138,17 @@ static int gpio_ir_tx(struct rc_dev *dev, unsigned int *txbuf,
}
spin_unlock_irqrestore(&gpio_ir->lock, flags);
+}
+
+static int gpio_ir_tx(struct rc_dev *dev, unsigned int *txbuf,
+ unsigned int count)
+{
+ struct gpio_ir *gpio_ir = dev->priv;
+
+ if (gpio_ir->carrier)
+ gpio_ir_tx_modulated(gpio_ir, txbuf, count);
+ else
+ gpio_ir_tx_unmodulated(gpio_ir, txbuf, count);
return count;
}
--
2.26.2
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