x86: clk: clk-fch: Add support for newer family of AMD's SOC

FCH controller clock configuration slightly differs across AMD's
SOC architectures. Newer family of SOC only support a 48MHz fix
clock while stoney SOC family has a clk_mux to choose 48MHz and
25 MHz clk. At present fixed clk support is only enabled for RV
architecture using "is-rv" device property initialized from boot
loader. This limit 48MHz fixed clock gate support to RV platform
unless we add similar device property in boot loader for other
architectures.

Add pci_device_id table with Stoney platform id and replace "is-rv"
device property check with pci id match to add clk mux support with
25MHz and 48MHz clk support based on clk mux selection. This enable
48Mhz fixed fch clock support by default on all newer SOC's except
stoney. Also replace RV with FIXED as a generic naming conventions
across all platforms and changed module description.
Signed-off-by: Ajit Kumar Pandey <AjitKumar.Pandey@amd.com>
Reviewed-by: Mario Limonciello <Mario.Limonciello@amd.com>
Link: https://lore.kernel.org/r/20211212180527.1641362-2-AjitKumar.Pandey@amd.comSigned-off-by: Stephen Boyd <sboyd@kernel.org>

drivers/clk/x86/clk-fch.c

 // SPDX-License-Identifier: MIT
 /*
- * clock framework for AMD Stoney based clocks
+ * clock framework for AMD FCH controller block
  *
  * Copyright 2018 Advanced Micro Devices, Inc.
  */
@@ -8,6 +8,7 @@
 #include <linux/clk.h>
 #include <linux/clkdev.h>
 #include <linux/clk-provider.h>
+#include <linux/pci.h>
 #include <linux/platform_data/clk-fch.h>
 #include <linux/platform_device.h>
 
@@ -26,22 +27,37 @@
 #define ST_CLK_GATE	3
 #define ST_MAX_CLKS	4
 
-#define RV_CLK_48M	0
-#define RV_CLK_GATE	1
-#define RV_MAX_CLKS	2
+#define CLK_48M_FIXED	0
+#define CLK_GATE_FIXED	1
+#define CLK_MAX_FIXED	2
+
+/* List of supported CPU ids for clk mux with 25Mhz clk support */
+#define AMD_CPU_ID_ST                  0x1576
 
 static const char * const clk_oscout1_parents[] = { "clk48MHz", "clk25MHz" };
 static struct clk_hw *hws[ST_MAX_CLKS];
 
+static const struct pci_device_id fch_pci_ids[] = {
+	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, AMD_CPU_ID_ST) },
+	{ }
+};
+
 static int fch_clk_probe(struct platform_device *pdev)
 {
 	struct fch_clk_data *fch_data;
+	struct pci_dev *rdev;
 
 	fch_data = dev_get_platdata(&pdev->dev);
 	if (!fch_data || !fch_data->base)
 		return -EINVAL;
 
-	if (!fch_data->is_rv) {
+	rdev = pci_get_domain_bus_and_slot(0, 0, PCI_DEVFN(0, 0));
+	if (!rdev) {
+		dev_err(&pdev->dev, "FCH device not found\n");
+		return -ENODEV;
+	}
+
+	if (pci_match_id(fch_pci_ids, rdev)) {
 		hws[ST_CLK_48M] = clk_hw_register_fixed_rate(NULL, "clk48MHz",
 			NULL, 0, 48000000);
 		hws[ST_CLK_25M] = clk_hw_register_fixed_rate(NULL, "clk25MHz",
@@ -61,32 +77,36 @@ static int fch_clk_probe(struct platform_device *pdev)
 		devm_clk_hw_register_clkdev(&pdev->dev, hws[ST_CLK_GATE],
 			"oscout1", NULL);
 	} else {
-		hws[RV_CLK_48M] = clk_hw_register_fixed_rate(NULL, "clk48MHz",
+		hws[CLK_48M_FIXED] = clk_hw_register_fixed_rate(NULL, "clk48MHz",
 			NULL, 0, 48000000);
 
-		hws[RV_CLK_GATE] = clk_hw_register_gate(NULL, "oscout1",
+		hws[CLK_GATE_FIXED] = clk_hw_register_gate(NULL, "oscout1",
 			"clk48MHz", 0, fch_data->base + MISCCLKCNTL1,
 			OSCCLKENB, CLK_GATE_SET_TO_DISABLE, NULL);
 
-		devm_clk_hw_register_clkdev(&pdev->dev, hws[RV_CLK_GATE],
+		devm_clk_hw_register_clkdev(&pdev->dev, hws[CLK_GATE_FIXED],
 			"oscout1", NULL);
 	}
 
+	pci_dev_put(rdev);
 	return 0;
 }
 
 static int fch_clk_remove(struct platform_device *pdev)
 {
 	int i, clks;
-	struct fch_clk_data *fch_data;
+	struct pci_dev *rdev;
 
-	fch_data = dev_get_platdata(&pdev->dev);
+	rdev = pci_get_domain_bus_and_slot(0, 0, PCI_DEVFN(0, 0));
+	if (!rdev)
+		return -ENODEV;
 
-	clks = fch_data->is_rv ? RV_MAX_CLKS : ST_MAX_CLKS;
+	clks = pci_match_id(fch_pci_ids, rdev) ? CLK_MAX_FIXED : ST_MAX_CLKS;
 
 	for (i = 0; i < clks; i++)
 		clk_hw_unregister(hws[i]);
 
+	pci_dev_put(rdev);
 	return 0;
 }