diff options
Diffstat (limited to 'drivers/iio/humidity/dht11.c')
| -rw-r--r-- | drivers/iio/humidity/dht11.c | 40 |
1 files changed, 34 insertions, 6 deletions
diff --git a/drivers/iio/humidity/dht11.c b/drivers/iio/humidity/dht11.c index 20b500da9..9c47bc98f 100644 --- a/drivers/iio/humidity/dht11.c +++ b/drivers/iio/humidity/dht11.c @@ -96,6 +96,24 @@ struct dht11 { struct {s64 ts; int value; } edges[DHT11_EDGES_PER_READ]; }; +#ifdef CONFIG_DYNAMIC_DEBUG +/* + * dht11_edges_print: show the data as actually received by the + * driver. + */ +static void dht11_edges_print(struct dht11 *dht11) +{ + int i; + + dev_dbg(dht11->dev, "%d edges detected:\n", dht11->num_edges); + for (i = 1; i < dht11->num_edges; ++i) { + dev_dbg(dht11->dev, "%d: %lld ns %s\n", i, + dht11->edges[i].ts - dht11->edges[i - 1].ts, + dht11->edges[i - 1].value ? "high" : "low"); + } +} +#endif /* CONFIG_DYNAMIC_DEBUG */ + static unsigned char dht11_decode_byte(char *bits) { unsigned char ret = 0; @@ -119,8 +137,12 @@ static int dht11_decode(struct dht11 *dht11, int offset) for (i = 0; i < DHT11_BITS_PER_READ; ++i) { t = dht11->edges[offset + 2 * i + 2].ts - dht11->edges[offset + 2 * i + 1].ts; - if (!dht11->edges[offset + 2 * i + 1].value) - return -EIO; /* lost synchronisation */ + if (!dht11->edges[offset + 2 * i + 1].value) { + dev_dbg(dht11->dev, + "lost synchronisation at edge %d\n", + offset + 2 * i + 1); + return -EIO; + } bits[i] = t > DHT11_THRESHOLD; } @@ -130,8 +152,10 @@ static int dht11_decode(struct dht11 *dht11, int offset) temp_dec = dht11_decode_byte(&bits[24]); checksum = dht11_decode_byte(&bits[32]); - if (((hum_int + hum_dec + temp_int + temp_dec) & 0xff) != checksum) + if (((hum_int + hum_dec + temp_int + temp_dec) & 0xff) != checksum) { + dev_dbg(dht11->dev, "invalid checksum\n"); return -EIO; + } dht11->timestamp = ktime_get_boot_ns(); if (hum_int < 20) { /* DHT22 */ @@ -182,6 +206,7 @@ static int dht11_read_raw(struct iio_dev *iio_dev, mutex_lock(&dht11->lock); if (dht11->timestamp + DHT11_DATA_VALID_TIME < ktime_get_boot_ns()) { timeres = ktime_get_resolution_ns(); + dev_dbg(dht11->dev, "current timeresolution: %dns\n", timeres); if (timeres > DHT11_MIN_TIMERES) { dev_err(dht11->dev, "timeresolution %dns too low\n", timeres); @@ -219,10 +244,13 @@ static int dht11_read_raw(struct iio_dev *iio_dev, free_irq(dht11->irq, iio_dev); +#ifdef CONFIG_DYNAMIC_DEBUG + dht11_edges_print(dht11); +#endif + if (ret == 0 && dht11->num_edges < DHT11_EDGES_PER_READ - 1) { - dev_err(&iio_dev->dev, - "Only %d signal edges detected\n", - dht11->num_edges); + dev_err(dht11->dev, "Only %d signal edges detected\n", + dht11->num_edges); ret = -ETIMEDOUT; } if (ret < 0) |