[PATCH v1 6/7] iio: adc: qcom-spmi-iadc: Migrate to devm_spmi_subdevice_alloc_and_add()

[AngeloGioacchino Del Regno]

Some Qualcomm PMICs integrate an Current ADC device, reachable
in a specific address range over SPMI.

Instead of using the parent SPMI device (the main PMIC) as a kind
of syscon in this driver, register a new SPMI sub-device and
initialize its own regmap with this sub-device's specific base
address, retrieved from the devicetree.

This allows to stop manually adding the register base address to
every R/W call in this driver, as this can be, and is now, handled
by the regmap API instead.

Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno at collabora.com>
---
 drivers/iio/adc/qcom-spmi-iadc.c | 32 ++++++++++++++++++++++----------
 1 file changed, 22 insertions(+), 10 deletions(-)

diff --git a/drivers/iio/adc/qcom-spmi-iadc.c b/drivers/iio/adc/qcom-spmi-iadc.c
index b64a8a407168..34e31bb49f4f 100644
--- a/drivers/iio/adc/qcom-spmi-iadc.c
+++ b/drivers/iio/adc/qcom-spmi-iadc.c
@@ -16,6 +16,7 @@
 #include <linux/platform_device.h>
 #include <linux/regmap.h>
 #include <linux/slab.h>
+#include <linux/spmi.h>
 
 /* IADC register and bit definition */
 #define IADC_REVISION2				0x1
@@ -94,7 +95,6 @@
  * struct iadc_chip - IADC Current ADC device structure.
  * @regmap: regmap for register read/write.
  * @dev: This device pointer.
- * @base: base offset for the ADC peripheral.
  * @rsense: Values of the internal and external sense resister in micro Ohms.
  * @poll_eoc: Poll for end of conversion instead of waiting for IRQ.
  * @offset: Raw offset values for the internal and external channels.
@@ -105,7 +105,6 @@
 struct iadc_chip {
 	struct regmap	*regmap;
 	struct device	*dev;
-	u16		base;
 	bool		poll_eoc;
 	u32		rsense[2];
 	u16		offset[2];
@@ -119,7 +118,7 @@ static int iadc_read(struct iadc_chip *iadc, u16 offset, u8 *data)
 	unsigned int val;
 	int ret;
 
-	ret = regmap_read(iadc->regmap, iadc->base + offset, &val);
+	ret = regmap_read(iadc->regmap, offset, &val);
 	if (ret < 0)
 		return ret;
 
@@ -129,7 +128,7 @@ static int iadc_read(struct iadc_chip *iadc, u16 offset, u8 *data)
 
 static int iadc_write(struct iadc_chip *iadc, u16 offset, u8 data)
 {
-	return regmap_write(iadc->regmap, iadc->base + offset, data);
+	return regmap_write(iadc->regmap, offset, data);
 }
 
 static int iadc_reset(struct iadc_chip *iadc)
@@ -270,7 +269,7 @@ static int iadc_poll_wait_eoc(struct iadc_chip *iadc, unsigned int interval_us)
 
 static int iadc_read_result(struct iadc_chip *iadc, u16 *data)
 {
-	return regmap_bulk_read(iadc->regmap, iadc->base + IADC_DATA, data, 2);
+	return regmap_bulk_read(iadc->regmap, IADC_DATA, data, 2);
 }
 
 static int iadc_do_conversion(struct iadc_chip *iadc, int chan, u16 *data)
@@ -483,12 +482,19 @@ static const struct iio_chan_spec iadc_channels[] = {
 
 static int iadc_probe(struct platform_device *pdev)
 {
+	struct regmap_config iadc_regmap_config = {
+		.reg_bits = 16,
+		.val_bits = 16,
+		.max_register = 0x100,
+		.fast_io = true
+	};
 	struct device_node *node = pdev->dev.of_node;
 	struct device *dev = &pdev->dev;
+	struct spmi_subdevice *sub_sdev;
+	struct spmi_device *sparent;
 	struct iio_dev *indio_dev;
 	struct iadc_chip *iadc;
 	int ret, irq_eoc;
-	u32 res;
 
 	indio_dev = devm_iio_device_alloc(dev, sizeof(*iadc));
 	if (!indio_dev)
@@ -497,18 +503,24 @@ static int iadc_probe(struct platform_device *pdev)
 	iadc = iio_priv(indio_dev);
 	iadc->dev = dev;
 
-	iadc->regmap = dev_get_regmap(dev->parent, NULL);
-	if (!iadc->regmap)
+	sparent = to_spmi_device(pdev->dev.parent);
+	if (!sparent)
 		return -ENODEV;
 
+	sub_sdev = devm_spmi_subdevice_alloc_and_add(&pdev->dev, sparent);
+	if (IS_ERR(sub_sdev))
+		return PTR_ERR(sub_sdev);
+
 	init_completion(&iadc->complete);
 	mutex_init(&iadc->lock);
 
-	ret = of_property_read_u32(node, "reg", &res);
+	ret = of_property_read_u32(node, "reg", &iadc_regmap_config.reg_base);
 	if (ret < 0)
 		return -ENODEV;
 
-	iadc->base = res;
+	iadc->regmap = devm_regmap_init_spmi_ext(&sub_sdev->sdev, &iadc_regmap_config);
+	if (IS_ERR(iadc->regmap))
+		return PTR_ERR(iadc->regmap);
 
 	ret = iadc_version_check(iadc);
 	if (ret < 0)
-- 
2.50.1