Merge tag 'iio-fixes-for-4.0a' of git://git.kernel.org/pub/scm/linux/kernel/git/jic23/iio into staging-linus

Jonathan writes:

First round of fixes for IIO in the 4.0 cycle. Note a followup
set dependent on patches in the recent merge windows will follow shortly.

* dht11 - fix a read off the end of an array, add some locking to prevent
          the read function being interrupted and make sure gpio/irq lines
	  are not enabled for irqs during output.
* iadc - timeout should be in jiffies not msecs
* mpu6050 - avoid a null id from ACPI emumeration being dereferenced.
* mxs-lradc - fix up some interaction issues between the touchscreen driver
              and iio driver.  Mostly about making sure that the adc driver
              only affects channels that are not being used for the
              touchscreen.
* ad2s1200 - sign extension fix for a result of c type promotion.
* adis16400 - sign extension fix for a result of c type promotion.
* mcp3422 - scale table was transposed.
* ad5686 - use _optional regulator get to avoid a dummy reg being allocate
           which would cause the driver to fail to initialize.
* gp2ap020a00f - select REGMAP_I2C
* si7020 - revert an incorrect cleanup up and then fix the issue that made
           that cleanup seem like a good idea.

1 files changed, 41 insertions, 28 deletions

diff --git a/drivers/iio/humidity/dht11.c b/drivers/iio/humidity/dht11.c
index 623c145d8a97..7d79a1ac5f5f 100644
--- a/drivers/iio/humidity/dht11.c
+++ b/drivers/iio/humidity/dht11.c
@@ -29,6 +29,7 @@
 #include <linux/wait.h>
 #include <linux/bitops.h>
 #include <linux/completion.h>
+#include <linux/mutex.h>
 #include <linux/delay.h>
 #include <linux/gpio.h>
 #include <linux/of_gpio.h>
@@ -39,8 +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) */
@@ -57,6 +62,7 @@ struct dht11 {
 	int				irq;
 
 	struct completion		completion;
+	struct mutex			lock;
 
 	s64				timestamp;
 	int				temperature;
@@ -88,7 +94,7 @@ static int dht11_decode(struct dht11 *dht11, int offset)
 	unsigned char temp_int, temp_dec, hum_int, hum_dec, checksum;
 
 	/* Calculate timestamp resolution */
-	for (i = 0; i < dht11->num_edges; ++i) {
+	for (i = 1; i < dht11->num_edges; ++i) {
 		t = dht11->edges[i].ts - dht11->edges[i-1].ts;
 		if (t > 0 && t < timeres)
 			timeres = t;
@@ -138,6 +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)
@@ -145,6 +172,7 @@ static int dht11_read_raw(struct iio_dev *iio_dev,
 	struct dht11 *dht11 = iio_priv(iio_dev);
 	int ret;
 
+	mutex_lock(&dht11->lock);
 	if (dht11->timestamp + DHT11_DATA_VALID_TIME < iio_get_time_ns()) {
 		reinit_completion(&dht11->completion);
 
@@ -157,8 +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",
@@ -185,6 +222,7 @@ static int dht11_read_raw(struct iio_dev *iio_dev,
 		ret = -EINVAL;
 err:
 	dht11->num_edges = -1;
+	mutex_unlock(&dht11->lock);
 	return ret;
 }
 
@@ -193,27 +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), },
@@ -256,11 +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;
@@ -268,6 +280,7 @@ static int dht11_probe(struct platform_device *pdev)
 	platform_set_drvdata(pdev, iio);
 
 	init_completion(&dht11->completion);
+	mutex_init(&dht11->lock);
 	iio->name = pdev->name;
 	iio->dev.parent = &pdev->dev;
 	iio->info = &dht11_iio_info;