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iio: dht11: IRQ fixes 

Since setting irq-enabled GPIOs into output state is not supported
by all GPIO controllers, we need to disable the irq while requesting
sensor data. As side effect we lose a tiny bit of functionality:
Some wiring problems can't be concluded from log messages anymore.

Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Harald Geyer <harald@ccbib.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
This commit is contained in:
Richard Weinberger 2015-01-07 13:22:49 +01:00 committed by Jonathan Cameron
parent 004bc53034
commit 94e65519ab
1 changed files with 35 additions and 27 deletions
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62
drivers/iio/humidity/dht11.c
View File

@ -40,8 +40,12 @@
#define DHT11_DATA_VALID_TIME 2000000000 /* 2s in ns */
#define DHT11_EDGES_PREAMBLE 4
#define DHT11_EDGES_PREAMBLE 2
#define DHT11_BITS_PER_READ 40
/*
* Note that when reading the sensor actually 84 edges are detected, but
* since the last edge is not significant, we only store 83:
*/
#define DHT11_EDGES_PER_READ (2*DHT11_BITS_PER_READ + DHT11_EDGES_PREAMBLE + 1)
/* Data transmission timing (nano seconds) */
@ -140,6 +144,27 @@ static int dht11_decode(struct dht11 *dht11, int offset)
return 0;
}
/*
* IRQ handler called on GPIO edges
*/
static irqreturn_t dht11_handle_irq(int irq, void *data)
{
struct iio_dev *iio = data;
struct dht11 *dht11 = iio_priv(iio);
/* TODO: Consider making the handler safe for IRQ sharing */
if (dht11->num_edges < DHT11_EDGES_PER_READ && dht11->num_edges >= 0) {
dht11->edges[dht11->num_edges].ts = iio_get_time_ns();
dht11->edges[dht11->num_edges++].value =
gpio_get_value(dht11->gpio);
if (dht11->num_edges >= DHT11_EDGES_PER_READ)
complete(&dht11->completion);
}
return IRQ_HANDLED;
}
static int dht11_read_raw(struct iio_dev *iio_dev,
const struct iio_chan_spec *chan,
int *val, int *val2, long m)
@ -160,8 +185,17 @@ static int dht11_read_raw(struct iio_dev *iio_dev,
if (ret)
goto err;
ret = request_irq(dht11->irq, dht11_handle_irq,
IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING,
iio_dev->name, iio_dev);
if (ret)
goto err;
ret = wait_for_completion_killable_timeout(&dht11->completion,
HZ);
free_irq(dht11->irq, iio_dev);
if (ret == 0 && dht11->num_edges < DHT11_EDGES_PER_READ - 1) {
dev_err(&iio_dev->dev,
"Only %d signal edges detected\n",
@ -197,27 +231,6 @@ static const struct iio_info dht11_iio_info = {
.read_raw = dht11_read_raw,
};
/*
* IRQ handler called on GPIO edges
*/
static irqreturn_t dht11_handle_irq(int irq, void *data)
{
struct iio_dev *iio = data;
struct dht11 *dht11 = iio_priv(iio);
/* TODO: Consider making the handler safe for IRQ sharing */
if (dht11->num_edges < DHT11_EDGES_PER_READ && dht11->num_edges >= 0) {
dht11->edges[dht11->num_edges].ts = iio_get_time_ns();
dht11->edges[dht11->num_edges++].value =
gpio_get_value(dht11->gpio);
if (dht11->num_edges >= DHT11_EDGES_PER_READ)
complete(&dht11->completion);
}
return IRQ_HANDLED;
}
static const struct iio_chan_spec dht11_chan_spec[] = {
{ .type = IIO_TEMP,
.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED), },
@ -260,11 +273,6 @@ static int dht11_probe(struct platform_device *pdev)
dev_err(dev, "GPIO %d has no interrupt\n", dht11->gpio);
return -EINVAL;
}
ret = devm_request_irq(dev, dht11->irq, dht11_handle_irq,
IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING,
pdev->name, iio);
if (ret)
return ret;
dht11->timestamp = iio_get_time_ns() - DHT11_DATA_VALID_TIME - 1;
dht11->num_edges = -1;