nvmem: mtk-efuse: remove nvmem regmap dependency

Regmap raw accessors are bus specific implementations, using regmap raw
apis in nvmem breaks nvmem providers based on regmap mmio.
This patch moves to nvmem support in the driver to use callback
instead of regmap, which is what the nvmem core supports now.

Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/nvmem/mtk-efuse.c

@@ -14,15 +14,35 @@
 
 #include <linux/device.h>
 #include <linux/module.h>
+#include <linux/io.h>
 #include <linux/nvmem-provider.h>
 #include <linux/platform_device.h>
-#include <linux/regmap.h>
 
-static struct regmap_config mtk_regmap_config = {
-	.reg_bits = 32,
-	.val_bits = 32,
-	.reg_stride = 4,
-};
+static int mtk_reg_read(void *context,
+			unsigned int reg, void *_val, size_t bytes)
+{
+	void __iomem *base = context;
+	u32 *val = _val;
+	int i = 0, words = bytes / 4;
+
+	while (words--)
+		*val++ = readl(base + reg + (i++ * 4));
+
+	return 0;
+}
+
+static int mtk_reg_write(void *context,
+			 unsigned int reg, void *_val, size_t bytes)
+{
+	void __iomem *base = context;
+	u32 *val = _val;
+	int i = 0, words = bytes / 4;
+
+	while (words--)
+		writel(*val++, base + reg + (i++ * 4));
+
+	return 0;
+}
 
 static int mtk_efuse_probe(struct platform_device *pdev)
 {
@@ -30,7 +50,6 @@ static int mtk_efuse_probe(struct platform_device *pdev)
 	struct resource *res;
 	struct nvmem_device *nvmem;
 	struct nvmem_config *econfig;
-	struct regmap *regmap;
 	void __iomem *base;
 
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
@@ -42,14 +61,12 @@ static int mtk_efuse_probe(struct platform_device *pdev)
 	if (!econfig)
 		return -ENOMEM;
 
-	mtk_regmap_config.max_register = resource_size(res) - 1;
-
-	regmap = devm_regmap_init_mmio(dev, base, &mtk_regmap_config);
-	if (IS_ERR(regmap)) {
-		dev_err(dev, "regmap init failed\n");
-		return PTR_ERR(regmap);
-	}
-
+	econfig->stride = 4;
+	econfig->word_size = 4;
+	econfig->reg_read = mtk_reg_read;
+	econfig->reg_write = mtk_reg_write;
+	econfig->size = resource_size(res);
+	econfig->priv = base;
 	econfig->dev = dev;
 	econfig->owner = THIS_MODULE;
 	nvmem = nvmem_register(econfig);