Second set of IIO fixes for the 4.8 cycle.

We have a big rework of the kxsd9 driver queued up behind the fix below and
 a fix for a recent fix that was marked for stable.
 Hence this fix series is perhaps a little more urgent than average for IIO.
 * core
   - a fix for a fix in the last set.  The recent fix for blocking ops when
    ! task running left a path (unlikely one) in which the function return
    value was not set - so initialise it to 0.
   - The IIO_TYPE_FRACTIONAL code previously didn't cope with negative
   fractions.  Turned out a fix for this was in Analog's tree but hadn't made
   it upstream.
 * bmc150
   - reset chip at init time. At least one board out there ends up coming up
   in an unstable state due to noise during power up.  The reset does no
   harm on other boards.
 * kxsd9
   - Fix a bug in the reported scaling due to failing to set the integer
   part to 0.
 * hid-sensors-pressure
   - Output was in the wrong units to comply with the IIO ABI.
 * tools
   - iio_generic_buffer: Fix the trigger-less mode by ensuring we don't fault
     out for having no trigger when we explicitly said we didn't want to have
     one.
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Merge tag 'iio-fixes-for-4.8b' of git://git.kernel.org/pub/scm/linux/kernel/git/jic23/iio into staging-linus

Jonathan writes:

Second set of IIO fixes for the 4.8 cycle.

We have a big rework of the kxsd9 driver queued up behind the fix below and
a fix for a recent fix that was marked for stable.
Hence this fix series is perhaps a little more urgent than average for IIO.
* core
  - a fix for a fix in the last set.  The recent fix for blocking ops when
   ! task running left a path (unlikely one) in which the function return
   value was not set - so initialise it to 0.
  - The IIO_TYPE_FRACTIONAL code previously didn't cope with negative
  fractions.  Turned out a fix for this was in Analog's tree but hadn't made
  it upstream.
* bmc150
  - reset chip at init time. At least one board out there ends up coming up
  in an unstable state due to noise during power up.  The reset does no
  harm on other boards.
* kxsd9
  - Fix a bug in the reported scaling due to failing to set the integer
  part to 0.
* hid-sensors-pressure
  - Output was in the wrong units to comply with the IIO ABI.
* tools
  - iio_generic_buffer: Fix the trigger-less mode by ensuring we don't fault
    out for having no trigger when we explicitly said we didn't want to have
    one.

drivers/iio/accel/bmc150-accel-core.c

@@ -67,6 +67,9 @@
 #define BMC150_ACCEL_REG_PMU_BW		0x10
 #define BMC150_ACCEL_DEF_BW			125
 
+#define BMC150_ACCEL_REG_RESET			0x14
+#define BMC150_ACCEL_RESET_VAL			0xB6
+
 #define BMC150_ACCEL_REG_INT_MAP_0		0x19
 #define BMC150_ACCEL_INT_MAP_0_BIT_SLOPE	BIT(2)
 
@@ -1497,6 +1500,14 @@ static int bmc150_accel_chip_init(struct bmc150_accel_data *data)
 	int ret, i;
 	unsigned int val;
 
+	/*
+	 * Reset chip to get it in a known good state. A delay of 1.8ms after
+	 * reset is required according to the data sheets of supported chips.
+	 */
+	regmap_write(data->regmap, BMC150_ACCEL_REG_RESET,
+		     BMC150_ACCEL_RESET_VAL);
+	usleep_range(1800, 2500);
+
 	ret = regmap_read(data->regmap, BMC150_ACCEL_REG_CHIP_ID, &val);
 	if (ret < 0) {
 		dev_err(dev, "Error: Reading chip id\n");

drivers/iio/accel/kxsd9.c

@@ -166,6 +166,7 @@ static int kxsd9_read_raw(struct iio_dev *indio_dev,
 		ret = spi_w8r8(st->us, KXSD9_READ(KXSD9_REG_CTRL_C));
 		if (ret < 0)
 			goto error_ret;
+		*val = 0;
 		*val2 = kxsd9_micro_scales[ret & KXSD9_FS_MASK];
 		ret = IIO_VAL_INT_PLUS_MICRO;
 		break;

drivers/iio/common/hid-sensors/hid-sensor-attributes.c

@@ -56,8 +56,8 @@ static struct {
 	{HID_USAGE_SENSOR_ALS, 0, 1, 0},
 	{HID_USAGE_SENSOR_ALS, HID_USAGE_SENSOR_UNITS_LUX, 1, 0},
 
-	{HID_USAGE_SENSOR_PRESSURE, 0, 100000, 0},
-	{HID_USAGE_SENSOR_PRESSURE, HID_USAGE_SENSOR_UNITS_PASCAL, 1, 0},
+	{HID_USAGE_SENSOR_PRESSURE, 0, 100, 0},
+	{HID_USAGE_SENSOR_PRESSURE, HID_USAGE_SENSOR_UNITS_PASCAL, 0, 1000},
 };
 
 static int pow_10(unsigned power)

drivers/iio/industrialio-buffer.c

@@ -110,7 +110,7 @@ ssize_t iio_buffer_read_first_n_outer(struct file *filp, char __user *buf,
 	DEFINE_WAIT_FUNC(wait, woken_wake_function);
 	size_t datum_size;
 	size_t to_wait;
-	int ret;
+	int ret = 0;
 
 	if (!indio_dev->info)
 		return -ENODEV;
@@ -153,7 +153,7 @@ ssize_t iio_buffer_read_first_n_outer(struct file *filp, char __user *buf,
 		ret = rb->access->read_first_n(rb, n, buf);
 		if (ret == 0 && (filp->f_flags & O_NONBLOCK))
 			ret = -EAGAIN;
-	 } while (ret == 0);
+	} while (ret == 0);
 	remove_wait_queue(&rb->pollq, &wait);
 
 	return ret;

drivers/iio/industrialio-core.c

@@ -613,9 +613,8 @@ ssize_t iio_format_value(char *buf, unsigned int type, int size, int *vals)
 			return sprintf(buf, "%d.%09u\n", vals[0], vals[1]);
 	case IIO_VAL_FRACTIONAL:
 		tmp = div_s64((s64)vals[0] * 1000000000LL, vals[1]);
-		vals[1] = do_div(tmp, 1000000000LL);
-		vals[0] = tmp;
-		return sprintf(buf, "%d.%09u\n", vals[0], vals[1]);
+		vals[0] = (int)div_s64_rem(tmp, 1000000000, &vals[1]);
+		return sprintf(buf, "%d.%09u\n", vals[0], abs(vals[1]));
 	case IIO_VAL_FRACTIONAL_LOG2:
 		tmp = (s64)vals[0] * 1000000000LL >> vals[1];
 		vals[1] = do_div(tmp, 1000000000LL);

tools/iio/iio_generic_buffer.c

@@ -456,7 +456,7 @@ int main(int argc, char **argv)
 
 	if (notrigger) {
 		printf("trigger-less mode selected\n");
-	} if (trig_num >= 0) {
+	} else if (trig_num >= 0) {
 		char *trig_dev_name;
 		ret = asprintf(&trig_dev_name, "%strigger%d", iio_dir, trig_num);
 		if (ret < 0) {