[PATCH v1 2/7] nvmem: qcom-spmi-sdam: Migrate to devm_spmi_subdevice_alloc_and_add()

[AngeloGioacchino Del Regno]

Some Qualcomm PMICs integrate a SDAM device, internally located in
a specific address range reachable through SPMI communication.

Instead of using the parent SPMI device (the main PMIC) as a kind
of syscon in this driver, register a new SPMI sub-device for SDAM
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/nvmem/qcom-spmi-sdam.c | 41 +++++++++++++++++++++++++---------
 1 file changed, 30 insertions(+), 11 deletions(-)

diff --git a/drivers/nvmem/qcom-spmi-sdam.c b/drivers/nvmem/qcom-spmi-sdam.c
index 4f1cca6eab71..1b80e8563a33 100644
--- a/drivers/nvmem/qcom-spmi-sdam.c
+++ b/drivers/nvmem/qcom-spmi-sdam.c
@@ -9,6 +9,7 @@
 #include <linux/nvmem-provider.h>
 #include <linux/platform_device.h>
 #include <linux/regmap.h>
+#include <linux/spmi.h>
 
 #define SDAM_MEM_START			0x40
 #define REGISTER_MAP_ID			0x40
@@ -20,7 +21,6 @@
 struct sdam_chip {
 	struct regmap			*regmap;
 	struct nvmem_config		sdam_config;
-	unsigned int			base;
 	unsigned int			size;
 };
 
@@ -73,7 +73,7 @@ static int sdam_read(void *priv, unsigned int offset, void *val,
 		return -EINVAL;
 	}
 
-	rc = regmap_bulk_read(sdam->regmap, sdam->base + offset, val, bytes);
+	rc = regmap_bulk_read(sdam->regmap, offset, val, bytes);
 	if (rc < 0)
 		dev_err(dev, "Failed to read SDAM offset %#x len=%zd, rc=%d\n",
 						offset, bytes, rc);
@@ -100,7 +100,7 @@ static int sdam_write(void *priv, unsigned int offset, void *val,
 		return -EINVAL;
 	}
 
-	rc = regmap_bulk_write(sdam->regmap, sdam->base + offset, val, bytes);
+	rc = regmap_bulk_write(sdam->regmap, offset, val, bytes);
 	if (rc < 0)
 		dev_err(dev, "Failed to write SDAM offset %#x len=%zd, rc=%d\n",
 						offset, bytes, rc);
@@ -110,28 +110,47 @@ static int sdam_write(void *priv, unsigned int offset, void *val,
 
 static int sdam_probe(struct platform_device *pdev)
 {
+	struct regmap_config sdam_regmap_config = {
+		.reg_bits = 16,
+		.val_bits = 16,
+		.max_register = 0x100,
+		.fast_io = true
+	};
 	struct sdam_chip *sdam;
 	struct nvmem_device *nvmem;
+	struct spmi_device *sparent;
+	struct spmi_subdevice *sub_sdev;
 	unsigned int val;
 	int rc;
 
+	if (!pdev->dev.parent)
+		return -ENODEV;
+
 	sdam = devm_kzalloc(&pdev->dev, sizeof(*sdam), GFP_KERNEL);
 	if (!sdam)
 		return -ENOMEM;
 
-	sdam->regmap = dev_get_regmap(pdev->dev.parent, NULL);
-	if (!sdam->regmap) {
-		dev_err(&pdev->dev, "Failed to get regmap handle\n");
-		return -ENXIO;
-	}
+	sparent = to_spmi_device(pdev->dev.parent);
+	if (!sparent)
+		return -ENODEV;
 
-	rc = of_property_read_u32(pdev->dev.of_node, "reg", &sdam->base);
+	sub_sdev = devm_spmi_subdevice_alloc_and_add(&pdev->dev, sparent);
+	if (IS_ERR(sub_sdev))
+		return PTR_ERR(sub_sdev);
+
+	rc = of_property_read_u32(pdev->dev.of_node, "reg", &sdam_regmap_config.reg_base);
 	if (rc < 0) {
 		dev_err(&pdev->dev, "Failed to get SDAM base, rc=%d\n", rc);
 		return -EINVAL;
 	}
 
-	rc = regmap_read(sdam->regmap, sdam->base + SDAM_SIZE, &val);
+	sdam->regmap = devm_regmap_init_spmi_ext(&sub_sdev->sdev, &sdam_regmap_config);
+	if (IS_ERR(sdam->regmap)) {
+		dev_err(&pdev->dev, "Failed to get regmap handle\n");
+		return PTR_ERR(sdam->regmap);
+	}
+
+	rc = regmap_read(sdam->regmap, SDAM_SIZE, &val);
 	if (rc < 0) {
 		dev_err(&pdev->dev, "Failed to read SDAM_SIZE rc=%d\n", rc);
 		return -EINVAL;
@@ -159,7 +178,7 @@ static int sdam_probe(struct platform_device *pdev)
 	}
 	dev_dbg(&pdev->dev,
 		"SDAM base=%#x size=%u registered successfully\n",
-		sdam->base, sdam->size);
+		sdam_regmap_config.reg_base, sdam->size);
 
 	return 0;
 }
-- 
2.50.1