drivers/clk/x86/clk-fch.c

   1 // SPDX-License-Identifier: MIT
   2 /*
   3  * clock framework for AMD FCH controller block
   4  *
   5  * Copyright 2018 Advanced Micro Devices, Inc.
   6  */
   7
   8 #include <linux/clk.h>
   9 #include <linux/clkdev.h>
  10 #include <linux/clk-provider.h>
  11 #include <linux/pci.h>
  12 #include <linux/platform_data/clk-fch.h>
  13 #include <linux/platform_device.h>
  14
  15 /* Clock Driving Strength 2 register */
  16 #define CLKDRVSTR2      0x28
  17 /* Clock Control 1 register */
  18 #define MISCCLKCNTL1    0x40
  19 /* Auxiliary clock1 enable bit */
  20 #define OSCCLKENB       2
  21 /* 25Mhz auxiliary output clock freq bit */
  22 #define OSCOUT1CLK25MHZ 16
  23
  24 #define ST_CLK_48M      0
  25 #define ST_CLK_25M      1
  26 #define ST_CLK_MUX      2
  27 #define ST_CLK_GATE     3
  28 #define ST_MAX_CLKS     4
  29
  30 #define CLK_48M_FIXED   0
  31 #define CLK_GATE_FIXED  1
  32 #define CLK_MAX_FIXED   2
  33
  34 /* List of supported CPU ids for clk mux with 25Mhz clk support */
  35 #define AMD_CPU_ID_ST                  0x1576
  36
  37 static const char * const clk_oscout1_parents[] = { "clk48MHz", "clk25MHz" };
  38 static struct clk_hw *hws[ST_MAX_CLKS];
  39
  40 static const struct pci_device_id fch_pci_ids[] = {
  41         { PCI_DEVICE(PCI_VENDOR_ID_AMD, AMD_CPU_ID_ST) },
  42         { }
  43 };
  44
  45 static int fch_clk_probe(struct platform_device *pdev)
  46 {
  47         struct fch_clk_data *fch_data;
  48         struct pci_dev *rdev;
  49
  50         fch_data = dev_get_platdata(&pdev->dev);
  51         if (!fch_data || !fch_data->base)
  52                 return -EINVAL;
  53
  54         rdev = pci_get_domain_bus_and_slot(0, 0, PCI_DEVFN(0, 0));
  55         if (!rdev) {
  56                 dev_err(&pdev->dev, "FCH device not found\n");
  57                 return -ENODEV;
  58         }
  59
  60         if (pci_match_id(fch_pci_ids, rdev)) {
  61                 hws[ST_CLK_48M] = clk_hw_register_fixed_rate(NULL, "clk48MHz",
  62                         NULL, 0, 48000000);
  63                 hws[ST_CLK_25M] = clk_hw_register_fixed_rate(NULL, "clk25MHz",
  64                         NULL, 0, 25000000);
  65
  66                 hws[ST_CLK_MUX] = clk_hw_register_mux(NULL, "oscout1_mux",
  67                         clk_oscout1_parents, ARRAY_SIZE(clk_oscout1_parents),
  68                         0, fch_data->base + CLKDRVSTR2, OSCOUT1CLK25MHZ, 3, 0,
  69                         NULL);
  70
  71                 clk_set_parent(hws[ST_CLK_MUX]->clk, hws[ST_CLK_48M]->clk);
  72
  73                 hws[ST_CLK_GATE] = clk_hw_register_gate(NULL, "oscout1",
  74                         "oscout1_mux", 0, fch_data->base + MISCCLKCNTL1,
  75                         OSCCLKENB, CLK_GATE_SET_TO_DISABLE, NULL);
  76
  77                 devm_clk_hw_register_clkdev(&pdev->dev, hws[ST_CLK_GATE],
  78                                             fch_data->name, NULL);
  79         } else {
  80                 hws[CLK_48M_FIXED] = clk_hw_register_fixed_rate(NULL, "clk48MHz",
  81                         NULL, 0, 48000000);
  82
  83                 hws[CLK_GATE_FIXED] = clk_hw_register_gate(NULL, "oscout1",
  84                         "clk48MHz", 0, fch_data->base + MISCCLKCNTL1,
  85                         OSCCLKENB, 0, NULL);
  86
  87                 devm_clk_hw_register_clkdev(&pdev->dev, hws[CLK_GATE_FIXED],
  88                                             fch_data->name, NULL);
  89         }
  90
  91         pci_dev_put(rdev);
  92         return 0;
  93 }
  94
  95 static void fch_clk_remove(struct platform_device *pdev)
  96 {
  97         int i, clks;
  98         struct pci_dev *rdev;
  99
 100         rdev = pci_get_domain_bus_and_slot(0, 0, PCI_DEVFN(0, 0));
 101         if (!rdev)
 102                 return;
 103
 104         clks = pci_match_id(fch_pci_ids, rdev) ? CLK_MAX_FIXED : ST_MAX_CLKS;
 105
 106         for (i = 0; i < clks; i++)
 107                 clk_hw_unregister(hws[i]);
 108
 109         pci_dev_put(rdev);
 110 }
 111
 112 static struct platform_driver fch_clk_driver = {
 113         .driver = {
 114                 .name = "clk-fch",
 115                 .suppress_bind_attrs = true,
 116         },
 117         .probe = fch_clk_probe,
 118         .remove = fch_clk_remove,
 119 };
 120 builtin_platform_driver(fch_clk_driver);