First round of IIO fixes for the 4.16 cycle.

One nasty very old crash around polling for buffers that aren't there
 - though that can only cause effects on drivers that support events
 but not buffers.
 
 * buffer / kfifo handling in the core.
   - Check there is a buffer and return 0 from poll directly if there
     isn't.  Poll doesn't make sense in this circumstances, but best to close
     the hole.
 * ad5933
   - Change the marked buffer mode to a software buffer as the meaning of
     the hardware buffer label has long since changed and this uses a front
     end software buffer anyway.
 * ad7192
   - Fix the fact the external clock frequency was only set when using the
     internal clock which was less than helpful.
 * adis_lib
   - Initialize the trigger before requesting the interrupt.  Some newer
     parts can power up with interrupt generation enabled so ordering now
     matters.
 * aspeed-adc
   - Fix an errror handling path as labels and general ordering were wrong.
 * srf08
   - Fix a link error due to undefined devm_iio_triggered_buffer_setup.
 * stm32-adc
   - Fix error handling unwind squence in stm32h7_adc_enable.
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Merge tag 'iio-fixes-for-4.16a' of git://git.kernel.org/pub/scm/linux/kernel/git/jic23/iio into staging-linus

Jonathan writes:

First round of IIO fixes for the 4.16 cycle.

One nasty very old crash around polling for buffers that aren't there
- though that can only cause effects on drivers that support events
but not buffers.

* buffer / kfifo handling in the core.
  - Check there is a buffer and return 0 from poll directly if there
    isn't.  Poll doesn't make sense in this circumstances, but best to close
    the hole.
* ad5933
  - Change the marked buffer mode to a software buffer as the meaning of
    the hardware buffer label has long since changed and this uses a front
    end software buffer anyway.
* ad7192
  - Fix the fact the external clock frequency was only set when using the
    internal clock which was less than helpful.
* adis_lib
  - Initialize the trigger before requesting the interrupt.  Some newer
    parts can power up with interrupt generation enabled so ordering now
    matters.
* aspeed-adc
  - Fix an errror handling path as labels and general ordering were wrong.
* srf08
  - Fix a link error due to undefined devm_iio_triggered_buffer_setup.
* stm32-adc
  - Fix error handling unwind squence in stm32h7_adc_enable.

drivers/iio/adc/aspeed_adc.c

@@ -243,7 +243,7 @@ static int aspeed_adc_probe(struct platform_device *pdev)
 					 ASPEED_ADC_INIT_POLLING_TIME,
 					 ASPEED_ADC_INIT_TIMEOUT);
 		if (ret)
-			goto scaler_error;
+			goto poll_timeout_error;
 	}
 
 	/* Start all channels in normal mode. */
@@ -274,9 +274,10 @@ iio_register_error:
 	writel(ASPEED_OPERATION_MODE_POWER_DOWN,
 		data->base + ASPEED_REG_ENGINE_CONTROL);
 	clk_disable_unprepare(data->clk_scaler->clk);
-reset_error:
-	reset_control_assert(data->rst);
 clk_enable_error:
+poll_timeout_error:
+	reset_control_assert(data->rst);
+reset_error:
 	clk_hw_unregister_divider(data->clk_scaler);
 scaler_error:
 	clk_hw_unregister_divider(data->clk_prescaler);

drivers/iio/adc/stm32-adc.c

@@ -722,8 +722,6 @@ static int stm32h7_adc_enable(struct stm32_adc *adc)
 	int ret;
 	u32 val;
 
-	/* Clear ADRDY by writing one, then enable ADC */
-	stm32_adc_set_bits(adc, STM32H7_ADC_ISR, STM32H7_ADRDY);
 	stm32_adc_set_bits(adc, STM32H7_ADC_CR, STM32H7_ADEN);
 
 	/* Poll for ADRDY to be set (after adc startup time) */
@@ -731,8 +729,11 @@ static int stm32h7_adc_enable(struct stm32_adc *adc)
 					   val & STM32H7_ADRDY,
 					   100, STM32_ADC_TIMEOUT_US);
 	if (ret) {
-		stm32_adc_clr_bits(adc, STM32H7_ADC_CR, STM32H7_ADEN);
+		stm32_adc_set_bits(adc, STM32H7_ADC_CR, STM32H7_ADDIS);
 		dev_err(&indio_dev->dev, "Failed to enable ADC\n");
+	} else {
+		/* Clear ADRDY by writing one */
+		stm32_adc_set_bits(adc, STM32H7_ADC_ISR, STM32H7_ADRDY);
 	}
 
 	return ret;

drivers/iio/imu/adis_trigger.c

@@ -46,6 +46,10 @@ int adis_probe_trigger(struct adis *adis, struct iio_dev *indio_dev)
 	if (adis->trig == NULL)
 		return -ENOMEM;
 
+	adis->trig->dev.parent = &adis->spi->dev;
+	adis->trig->ops = &adis_trigger_ops;
+	iio_trigger_set_drvdata(adis->trig, adis);
+
 	ret = request_irq(adis->spi->irq,
 			  &iio_trigger_generic_data_rdy_poll,
 			  IRQF_TRIGGER_RISING,
@@ -54,9 +58,6 @@ int adis_probe_trigger(struct adis *adis, struct iio_dev *indio_dev)
 	if (ret)
 		goto error_free_trig;
 
-	adis->trig->dev.parent = &adis->spi->dev;
-	adis->trig->ops = &adis_trigger_ops;
-	iio_trigger_set_drvdata(adis->trig, adis);
 	ret = iio_trigger_register(adis->trig);
 
 	indio_dev->trig = iio_trigger_get(adis->trig);

drivers/iio/industrialio-buffer.c

@@ -175,7 +175,7 @@ __poll_t iio_buffer_poll(struct file *filp,
 	struct iio_dev *indio_dev = filp->private_data;
 	struct iio_buffer *rb = indio_dev->buffer;
 
-	if (!indio_dev->info)
+	if (!indio_dev->info || rb == NULL)
 		return 0;
 
 	poll_wait(filp, &rb->pollq, wait);

drivers/iio/proximity/Kconfig

@@ -68,6 +68,8 @@ config SX9500
 
 config SRF08
 	tristate "Devantech SRF02/SRF08/SRF10 ultrasonic ranger sensor"
+	select IIO_BUFFER
+	select IIO_TRIGGERED_BUFFER
 	depends on I2C
 	help
 	  Say Y here to build a driver for Devantech SRF02/SRF08/SRF10

drivers/staging/iio/adc/ad7192.c

@@ -141,6 +141,8 @@
 #define AD7192_GPOCON_P1DAT	BIT(1) /* P1 state */
 #define AD7192_GPOCON_P0DAT	BIT(0) /* P0 state */
 
+#define AD7192_EXT_FREQ_MHZ_MIN	2457600
+#define AD7192_EXT_FREQ_MHZ_MAX	5120000
 #define AD7192_INT_FREQ_MHZ	4915200
 
 /* NOTE:
@@ -218,6 +220,12 @@ static int ad7192_calibrate_all(struct ad7192_state *st)
 				ARRAY_SIZE(ad7192_calib_arr));
 }
 
+static inline bool ad7192_valid_external_frequency(u32 freq)
+{
+	return (freq >= AD7192_EXT_FREQ_MHZ_MIN &&
+		freq <= AD7192_EXT_FREQ_MHZ_MAX);
+}
+
 static int ad7192_setup(struct ad7192_state *st,
 			const struct ad7192_platform_data *pdata)
 {
@@ -243,17 +251,20 @@ static int ad7192_setup(struct ad7192_state *st,
 			 id);
 
 	switch (pdata->clock_source_sel) {
-	case AD7192_CLK_EXT_MCLK1_2:
-	case AD7192_CLK_EXT_MCLK2:
-		st->mclk = AD7192_INT_FREQ_MHZ;
-		break;
 	case AD7192_CLK_INT:
 	case AD7192_CLK_INT_CO:
-		if (pdata->ext_clk_hz)
-			st->mclk = pdata->ext_clk_hz;
-		else
-			st->mclk = AD7192_INT_FREQ_MHZ;
+		st->mclk = AD7192_INT_FREQ_MHZ;
 		break;
+	case AD7192_CLK_EXT_MCLK1_2:
+	case AD7192_CLK_EXT_MCLK2:
+		if (ad7192_valid_external_frequency(pdata->ext_clk_hz)) {
+			st->mclk = pdata->ext_clk_hz;
+			break;
+		}
+		dev_err(&st->sd.spi->dev, "Invalid frequency setting %u\n",
+			pdata->ext_clk_hz);
+		ret = -EINVAL;
+		goto out;
 	default:
 		ret = -EINVAL;
 		goto out;

drivers/staging/iio/impedance-analyzer/ad5933.c

@@ -648,8 +648,6 @@ static int ad5933_register_ring_funcs_and_init(struct iio_dev *indio_dev)
 	/* Ring buffer functions - here trigger setup related */
 	indio_dev->setup_ops = &ad5933_ring_setup_ops;
 
-	indio_dev->modes |= INDIO_BUFFER_HARDWARE;
-
 	return 0;
 }
 
@@ -762,7 +760,7 @@ static int ad5933_probe(struct i2c_client *client,
 	indio_dev->dev.parent = &client->dev;
 	indio_dev->info = &ad5933_info;
 	indio_dev->name = id->name;
-	indio_dev->modes = INDIO_DIRECT_MODE;
+	indio_dev->modes = (INDIO_BUFFER_SOFTWARE | INDIO_DIRECT_MODE);
 	indio_dev->channels = ad5933_channels;
 	indio_dev->num_channels = ARRAY_SIZE(ad5933_channels);