nvmem: rockchip-efuse: add optional property to get efuse size

The exact efuse size is defined in property <reg> before, this assume
that the length of registers is equal to efuse size, but it not true
for some chips, so we need anothor property to redefine efuse size.

Change-Id: I9cdab8adc2a13b55cfcacc3c2248295c4387a806
Signed-off-by: Chen Liang <cl@rock-chips.com>

Documentation/devicetree/bindings/nvmem/rockchip-efuse.txt

@@ -13,6 +13,10 @@ Required properties:
 - clocks: Should be the clock id of eFuse
 - clock-names: Should be "pclk_efuse"
 
+Optional properties:
+- rockchip,efuse-size: Should be exact eFuse size in byte, the eFuse
+  size in property <reg> will be invalid if define this property.
+
 Deprecated properties:
 - compatible: "rockchip,rockchip-efuse"
   Old efuse compatible value compatible to rk3066a, rk3188 and rk3288

drivers/nvmem/rockchip-efuse.c

@@ -361,7 +361,12 @@ static int __init rockchip_efuse_probe(struct platform_device *pdev)
 		return PTR_ERR(efuse->clk);
 
 	efuse->dev = &pdev->dev;
-	econfig.size = resource_size(res);
+	if (of_property_read_u32_index(dev->of_node,
+				       "rockchip,efuse-size",
+				       0,
+				       &econfig.size))
+		econfig.size = resource_size(res);
+
 	econfig.reg_read = match->data;
 	econfig.priv = efuse;
 	econfig.dev = efuse->dev;