PCI: keystone: Use phandle argument from "ti,syscon-pcie-id"/"ti,syscon-pcie-mode"

Get "syscon" pcie_mode and pcie_id offset from the argument of
"ti,syscon-pcie-id" and "ti,syscon-pcie-mode" phandle respectively.
Previously a subnode to "syscon" node was added which has the
exact memory mapped address of pcie_mode and pcie_id but now the
offset of pcie_mode and pcie_id within "syscon" is now being passed
as argument to "ti,syscon-pcie-id" and "ti,syscon-pcie-mode" phandle.

If the offset is not provided in "ti,syscon-pcie-id"/"ti,syscon-pcie-mode",
the full memory mapped address of pcie_ctrl is used in order to maintain
old DT compatibility.

Similar change for J721E is as discussed in [1]

[1] -> http://lore.kernel.org/r/CAL_JsqKiUcO76bo1GoepWM1TusJWoty_BRy2hFSgtEVMqtrvvQ@mail.gmail.com

Link: https://lore.kernel.org/r/20211126083119.16570-3-kishon@ti.comSigned-off-by: Kishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>

drivers/pci/controller/dwc/pci-keystone.c

@@ -775,12 +775,19 @@ static int __init ks_pcie_init_id(struct keystone_pcie *ks_pcie)
 	struct dw_pcie *pci = ks_pcie->pci;
 	struct device *dev = pci->dev;
 	struct device_node *np = dev->of_node;
+	struct of_phandle_args args;
+	unsigned int offset = 0;
 
 	devctrl_regs = syscon_regmap_lookup_by_phandle(np, "ti,syscon-pcie-id");
 	if (IS_ERR(devctrl_regs))
 		return PTR_ERR(devctrl_regs);
 
-	ret = regmap_read(devctrl_regs, 0, &id);
+	/* Do not error out to maintain old DT compatibility */
+	ret = of_parse_phandle_with_fixed_args(np, "ti,syscon-pcie-id", 1, 0, &args);
+	if (!ret)
+		offset = args.args[0];
+
+	ret = regmap_read(devctrl_regs, offset, &id);
 	if (ret)
 		return ret;
 
@@ -989,6 +996,8 @@ static int ks_pcie_enable_phy(struct keystone_pcie *ks_pcie)
 static int ks_pcie_set_mode(struct device *dev)
 {
 	struct device_node *np = dev->of_node;
+	struct of_phandle_args args;
+	unsigned int offset = 0;
 	struct regmap *syscon;
 	u32 val;
 	u32 mask;
@@ -998,10 +1007,15 @@ static int ks_pcie_set_mode(struct device *dev)
 	if (IS_ERR(syscon))
 		return 0;
 
+	/* Do not error out to maintain old DT compatibility */
+	ret = of_parse_phandle_with_fixed_args(np, "ti,syscon-pcie-mode", 1, 0, &args);
+	if (!ret)
+		offset = args.args[0];
+
 	mask = KS_PCIE_DEV_TYPE_MASK | KS_PCIE_SYSCLOCKOUTEN;
 	val = KS_PCIE_DEV_TYPE(RC) | KS_PCIE_SYSCLOCKOUTEN;
 
-	ret = regmap_update_bits(syscon, 0, mask, val);
+	ret = regmap_update_bits(syscon, offset, mask, val);
 	if (ret) {
 		dev_err(dev, "failed to set pcie mode\n");
 		return ret;
@@ -1014,6 +1028,8 @@ static int ks_pcie_am654_set_mode(struct device *dev,
 				  enum dw_pcie_device_mode mode)
 {
 	struct device_node *np = dev->of_node;
+	struct of_phandle_args args;
+	unsigned int offset = 0;
 	struct regmap *syscon;
 	u32 val;
 	u32 mask;
@@ -1023,6 +1039,11 @@ static int ks_pcie_am654_set_mode(struct device *dev,
 	if (IS_ERR(syscon))
 		return 0;
 
+	/* Do not error out to maintain old DT compatibility */
+	ret = of_parse_phandle_with_fixed_args(np, "ti,syscon-pcie-mode", 1, 0, &args);
+	if (!ret)
+		offset = args.args[0];
+
 	mask = AM654_PCIE_DEV_TYPE_MASK;
 
 	switch (mode) {
@@ -1037,7 +1058,7 @@ static int ks_pcie_am654_set_mode(struct device *dev,
 		return -EINVAL;
 	}
 
-	ret = regmap_update_bits(syscon, 0, mask, val);
+	ret = regmap_update_bits(syscon, offset, mask, val);
 	if (ret) {
 		dev_err(dev, "failed to set pcie mode\n");
 		return ret;