iio: adc: adi-axi-adc: convert to regmap

Use MMIO regmap interface. It makes things easier for manipulating bits.

Reviewed-by: David Lechner <dlechner@baylibre.com>
Signed-off-by: Nuno Sa <nuno.sa@analog.com>
Link: https://lore.kernel.org/r/20231207-iio-backend-prep-v2-8-a4a33bc4d70e@analog.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/adc/Kconfig

@@ -292,7 +292,7 @@ config ADI_AXI_ADC
 	select IIO_BUFFER
 	select IIO_BUFFER_HW_CONSUMER
 	select IIO_BUFFER_DMAENGINE
-	depends on HAS_IOMEM
+	select REGMAP_MMIO
 	depends on OF
 	help
 	  Say yes here to build support for Analog Devices Generic

drivers/iio/adc/adi-axi-adc.c

@@ -14,6 +14,7 @@
 #include <linux/of.h>
 #include <linux/platform_device.h>
 #include <linux/property.h>
+#include <linux/regmap.h>
 #include <linux/slab.h>
 
 #include <linux/iio/iio.h>
@@ -62,7 +63,7 @@ struct adi_axi_adc_state {
 	struct mutex				lock;
 
 	struct adi_axi_adc_client		*client;
-	void __iomem				*regs;
+	struct regmap				*regmap;
 };
 
 struct adi_axi_adc_client {
@@ -90,19 +91,6 @@ void *adi_axi_adc_conv_priv(struct adi_axi_adc_conv *conv)
 }
 EXPORT_SYMBOL_NS_GPL(adi_axi_adc_conv_priv, IIO_ADI_AXI);
 
-static void adi_axi_adc_write(struct adi_axi_adc_state *st,
-			      unsigned int reg,
-			      unsigned int val)
-{
-	iowrite32(val, st->regs + reg);
-}
-
-static unsigned int adi_axi_adc_read(struct adi_axi_adc_state *st,
-				     unsigned int reg)
-{
-	return ioread32(st->regs + reg);
-}
-
 static int adi_axi_adc_config_dma_buffer(struct device *dev,
 					 struct iio_dev *indio_dev)
 {
@@ -163,17 +151,20 @@ static int adi_axi_adc_update_scan_mode(struct iio_dev *indio_dev,
 {
 	struct adi_axi_adc_state *st = iio_priv(indio_dev);
 	struct adi_axi_adc_conv *conv = &st->client->conv;
-	unsigned int i, ctrl;
+	unsigned int i;
+	int ret;
 
 	for (i = 0; i < conv->chip_info->num_channels; i++) {
-		ctrl = adi_axi_adc_read(st, ADI_AXI_REG_CHAN_CTRL(i));
-
 		if (test_bit(i, scan_mask))
-			ctrl |= ADI_AXI_REG_CHAN_CTRL_ENABLE;
+			ret = regmap_set_bits(st->regmap,
+					      ADI_AXI_REG_CHAN_CTRL(i),
+					      ADI_AXI_REG_CHAN_CTRL_ENABLE);
 		else
-			ctrl &= ~ADI_AXI_REG_CHAN_CTRL_ENABLE;
-
-		adi_axi_adc_write(st, ADI_AXI_REG_CHAN_CTRL(i), ctrl);
+			ret = regmap_clear_bits(st->regmap,
+						ADI_AXI_REG_CHAN_CTRL(i),
+						ADI_AXI_REG_CHAN_CTRL_ENABLE);
+		if (ret)
+			return ret;
 	}
 
 	return 0;
@@ -310,21 +301,32 @@ static int adi_axi_adc_setup_channels(struct device *dev,
 	}
 
 	for (i = 0; i < conv->chip_info->num_channels; i++) {
-		adi_axi_adc_write(st, ADI_AXI_REG_CHAN_CTRL(i),
-				  ADI_AXI_REG_CHAN_CTRL_DEFAULTS);
+		ret = regmap_write(st->regmap, ADI_AXI_REG_CHAN_CTRL(i),
+				   ADI_AXI_REG_CHAN_CTRL_DEFAULTS);
+		if (ret)
+			return ret;
 	}
 
 	return 0;
 }
 
-static void axi_adc_reset(struct adi_axi_adc_state *st)
+static int axi_adc_reset(struct adi_axi_adc_state *st)
 {
-	adi_axi_adc_write(st, ADI_AXI_REG_RSTN, 0);
+	int ret;
+
+	ret = regmap_write(st->regmap, ADI_AXI_REG_RSTN, 0);
+	if (ret)
+		return ret;
+
 	mdelay(10);
-	adi_axi_adc_write(st, ADI_AXI_REG_RSTN, ADI_AXI_REG_RSTN_MMCM_RSTN);
+	ret = regmap_write(st->regmap, ADI_AXI_REG_RSTN,
+			   ADI_AXI_REG_RSTN_MMCM_RSTN);
+	if (ret)
+		return ret;
+
 	mdelay(10);
-	adi_axi_adc_write(st, ADI_AXI_REG_RSTN,
-			  ADI_AXI_REG_RSTN_RSTN | ADI_AXI_REG_RSTN_MMCM_RSTN);
+	return regmap_write(st->regmap, ADI_AXI_REG_RSTN,
+			    ADI_AXI_REG_RSTN_RSTN | ADI_AXI_REG_RSTN_MMCM_RSTN);
 }
 
 static void adi_axi_adc_cleanup(void *data)
@@ -335,12 +337,20 @@ static void adi_axi_adc_cleanup(void *data)
 	module_put(cl->dev->driver->owner);
 }
 
+static const struct regmap_config axi_adc_regmap_config = {
+	.val_bits = 32,
+	.reg_bits = 32,
+	.reg_stride = 4,
+	.max_register = 0x0800,
+};
+
 static int adi_axi_adc_probe(struct platform_device *pdev)
 {
 	struct adi_axi_adc_conv *conv;
 	struct iio_dev *indio_dev;
 	struct adi_axi_adc_client *cl;
 	struct adi_axi_adc_state *st;
+	void __iomem *base;
 	unsigned int ver;
 	int ret;
 
@@ -361,15 +371,24 @@ static int adi_axi_adc_probe(struct platform_device *pdev)
 	cl->state = st;
 	mutex_init(&st->lock);
 
-	st->regs = devm_platform_ioremap_resource(pdev, 0);
-	if (IS_ERR(st->regs))
-		return PTR_ERR(st->regs);
+	base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(base))
+		return PTR_ERR(base);
+
+	st->regmap = devm_regmap_init_mmio(&pdev->dev, base,
+					   &axi_adc_regmap_config);
+	if (IS_ERR(st->regmap))
+		return PTR_ERR(st->regmap);
 
 	conv = &st->client->conv;
 
-	axi_adc_reset(st);
+	ret = axi_adc_reset(st);
+	if (ret)
+		return ret;
 
-	ver = adi_axi_adc_read(st, ADI_AXI_REG_VERSION);
+	ret = regmap_read(st->regmap, ADI_AXI_REG_VERSION, &ver);
+	if (ret)
+		return ret;
 
 	if (cl->info->version > ver) {
 		dev_err(&pdev->dev,