[PATCH v3 2/6] iio: adc: xilinx-xadc: Add helper functions for the device setup

[Dileep Kumar Nagavarapu]

Refactor the platform driver probe function by extracting device
setup and configuration logic into reusable helper functions:
xadc_device_setup(): handles IIO device allocation and basic setup
xadc_device_configure(): handles device tree parsing and bipolar mask
configuration

This refactoring reduces code duplication and prepares for sharing the
common setup logic between platform and I2C drivers.

Co-developed-by: Sai Krishna Potthuri <sai.krishna.potthuri@xxxxxxx>
Signed-off-by: Sai Krishna Potthuri <sai.krishna.potthuri@xxxxxxx>
Signed-off-by: Dileep Kumar Nagavarapu <DileepKumar.Nagavarapu@xxxxxxx>
---
 drivers/iio/adc/xilinx-xadc-core.c | 104 ++++++++++++++++++++---------
 1 file changed, 73 insertions(+), 31 deletions(-)

diff --git a/drivers/iio/adc/xilinx-xadc-core.c b/drivers/iio/adc/xilinx-xadc-core.c
index b468179736f7..dd1470d2bf9b 100644
--- a/drivers/iio/adc/xilinx-xadc-core.c
+++ b/drivers/iio/adc/xilinx-xadc-core.c
@@ -194,12 +194,13 @@ static int xadc_zynq_write_adc_reg(struct xadc *xadc, unsigned int reg, u16 val)
 	ret = wait_for_completion_interruptible_timeout(&xadc->completion, HZ);
 	if (ret == 0)
 		ret = -EIO;
-	else
-		ret = 0;
+
+	if (ret < 0)
+		return ret;
 
 	xadc_read_reg(xadc, XADC_ZYNQ_REG_DFIFO, &tmp);
 
-	return ret;
+	return 0;
 }
 
 static int xadc_zynq_read_adc_reg(struct xadc *xadc, unsigned int reg, u16 *val)
@@ -950,6 +951,33 @@ static int xadc_read_raw(struct iio_dev *indio_dev,
 	}
 }
 
+int xadc_setup_buffer_and_triggers(struct iio_dev *indio_dev, int irq)
+{
+	struct xadc *xadc = iio_priv(indio_dev);
+	struct device *dev = indio_dev->dev.parent;
+	int ret;
+
+	if (!(xadc->ops->flags & XADC_FLAGS_BUFFERED))
+		return 0;
+
+	ret = devm_iio_triggered_buffer_setup(dev, indio_dev, &iio_pollfunc_store_time,
+					      &xadc_trigger_handler, &xadc_buffer_ops);
+	if (ret)
+		return ret;
+
+	if (irq > 0) {
+		xadc->convst_trigger = xadc_alloc_trigger(indio_dev, "convst");
+		if (IS_ERR(xadc->convst_trigger))
+			return PTR_ERR(xadc->convst_trigger);
+
+		xadc->samplerate_trigger = xadc_alloc_trigger(indio_dev, "samplerate");
+		if (IS_ERR(xadc->samplerate_trigger))
+			return PTR_ERR(xadc->samplerate_trigger);
+	}
+
+	return 0;
+}
+
 static int xadc_write_samplerate(struct xadc *xadc, int val)
 {
 	unsigned long clk_rate = xadc_get_dclk_rate(xadc);
@@ -1274,6 +1302,41 @@ static const char *const xadc_type_names[] = {
 	[XADC_TYPE_US] = "xilinx-system-monitor",
 };
 
+struct iio_dev *xadc_device_setup(struct device *dev, int size, const struct xadc_ops **ops)
+{
+	struct iio_dev *indio_dev;
+
+	*ops = device_get_match_data(dev);
+
+	indio_dev = devm_iio_device_alloc(dev, size);
+	if (!indio_dev)
+		return ERR_PTR(-ENOMEM);
+
+	indio_dev->name = xadc_type_names[(*ops)->type];
+	indio_dev->info = &xadc_info;
+	indio_dev->modes = INDIO_DIRECT_MODE;
+
+	return indio_dev;
+}
+
+int xadc_device_configure(struct device *dev, struct iio_dev *indio_dev, int irq,
+			  unsigned int *conf0, unsigned int *bipolar_mask)
+{
+	int ret;
+
+	ret = xadc_parse_dt(indio_dev, conf0, irq);
+	if (ret)
+		return ret;
+
+	*bipolar_mask = 0;
+	for (unsigned int i = 0; i < indio_dev->num_channels; i++) {
+		if (indio_dev->channels[i].scan_type.sign == 's')
+			*bipolar_mask |= BIT(indio_dev->channels[i].scan_index);
+	}
+
+	return 0;
+}
+
 static void xadc_cancel_delayed_work(void *data)
 {
 	struct delayed_work *work = data;
@@ -1293,18 +1356,14 @@ static int xadc_probe(struct platform_device *pdev)
 	int irq;
 	int i;
 
-	ops = device_get_match_data(dev);
-	if (!ops)
-		return -EINVAL;
+	indio_dev = xadc_device_setup(dev, sizeof(*xadc), &ops);
+	if (IS_ERR(indio_dev))
+		return PTR_ERR(indio_dev);
 
 	irq = platform_get_irq_optional(pdev, 0);
 	if (irq < 0 && (irq != -ENXIO || !(ops->flags & XADC_FLAGS_IRQ_OPTIONAL)))
 		return irq;
 
-	indio_dev = devm_iio_device_alloc(dev, sizeof(*xadc));
-	if (!indio_dev)
-		return -ENOMEM;
-
 	xadc = iio_priv(indio_dev);
 	xadc->ops = ops;
 	init_completion(&xadc->completion);
@@ -1316,30 +1375,13 @@ static int xadc_probe(struct platform_device *pdev)
 	if (IS_ERR(xadc->base))
 		return PTR_ERR(xadc->base);
 
-	indio_dev->name = xadc_type_names[xadc->ops->type];
-	indio_dev->modes = INDIO_DIRECT_MODE;
-	indio_dev->info = &xadc_info;
-
-	ret = xadc_parse_dt(indio_dev, &conf0, irq);
+	ret = xadc_device_configure(dev, indio_dev, irq, &conf0, &bipolar_mask);
 	if (ret)
 		return ret;
 
-	if (xadc->ops->flags & XADC_FLAGS_BUFFERED) {
-		ret = devm_iio_triggered_buffer_setup(dev, indio_dev, &iio_pollfunc_store_time,
-						      &xadc_trigger_handler, &xadc_buffer_ops);
-		if (ret)
-			return ret;
-
-		if (irq > 0) {
-			xadc->convst_trigger = xadc_alloc_trigger(indio_dev, "convst");
-			if (IS_ERR(xadc->convst_trigger))
-				return PTR_ERR(xadc->convst_trigger);
-
-			xadc->samplerate_trigger = xadc_alloc_trigger(indio_dev, "samplerate");
-			if (IS_ERR(xadc->samplerate_trigger))
-				return PTR_ERR(xadc->samplerate_trigger);
-		}
-	}
+	ret = xadc_setup_buffer_and_triggers(indio_dev, irq);
+	if (ret)
+		return ret;
 
 	xadc->clk = devm_clk_get_enabled(dev, NULL);
 	if (IS_ERR(xadc->clk))
-- 
2.34.1