drivers/clk/versatile/clk-vexpress-osc.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  *
   4  * Copyright (C) 2012 ARM Limited
   5  */
   6
   7 #include <linux/clkdev.h>
   8 #include <linux/clk-provider.h>
   9 #include <linux/err.h>
  10 #include <linux/module.h>
  11 #include <linux/of.h>
  12 #include <linux/platform_device.h>
  13 #include <linux/slab.h>
  14 #include <linux/vexpress.h>
  15
  16 struct vexpress_osc {
  17         struct regmap *reg;
  18         struct clk_hw hw;
  19         unsigned long rate_min;
  20         unsigned long rate_max;
  21 };
  22
  23 #define to_vexpress_osc(osc) container_of(osc, struct vexpress_osc, hw)
  24
  25 static unsigned long vexpress_osc_recalc_rate(struct clk_hw *hw,
  26                 unsigned long parent_rate)
  27 {
  28         struct vexpress_osc *osc = to_vexpress_osc(hw);
  29         u32 rate;
  30
  31         regmap_read(osc->reg, 0, &rate);
  32
  33         return rate;
  34 }
  35
  36 static long vexpress_osc_round_rate(struct clk_hw *hw, unsigned long rate,
  37                 unsigned long *parent_rate)
  38 {
  39         struct vexpress_osc *osc = to_vexpress_osc(hw);
  40
  41         if (osc->rate_min && rate < osc->rate_min)
  42                 rate = osc->rate_min;
  43
  44         if (osc->rate_max && rate > osc->rate_max)
  45                 rate = osc->rate_max;
  46
  47         return rate;
  48 }
  49
  50 static int vexpress_osc_set_rate(struct clk_hw *hw, unsigned long rate,
  51                 unsigned long parent_rate)
  52 {
  53         struct vexpress_osc *osc = to_vexpress_osc(hw);
  54
  55         return regmap_write(osc->reg, 0, rate);
  56 }
  57
  58 static const struct clk_ops vexpress_osc_ops = {
  59         .recalc_rate = vexpress_osc_recalc_rate,
  60         .round_rate = vexpress_osc_round_rate,
  61         .set_rate = vexpress_osc_set_rate,
  62 };
  63
  64
  65 static int vexpress_osc_probe(struct platform_device *pdev)
  66 {
  67         struct clk_init_data init;
  68         struct vexpress_osc *osc;
  69         u32 range[2];
  70         int ret;
  71
  72         osc = devm_kzalloc(&pdev->dev, sizeof(*osc), GFP_KERNEL);
  73         if (!osc)
  74                 return -ENOMEM;
  75
  76         osc->reg = devm_regmap_init_vexpress_config(&pdev->dev);
  77         if (IS_ERR(osc->reg))
  78                 return PTR_ERR(osc->reg);
  79
  80         if (of_property_read_u32_array(pdev->dev.of_node, "freq-range", range,
  81                         ARRAY_SIZE(range)) == 0) {
  82                 osc->rate_min = range[0];
  83                 osc->rate_max = range[1];
  84         }
  85
  86         if (of_property_read_string(pdev->dev.of_node, "clock-output-names",
  87                         &init.name) != 0)
  88                 init.name = dev_name(&pdev->dev);
  89
  90         init.ops = &vexpress_osc_ops;
  91         init.flags = 0;
  92         init.num_parents = 0;
  93
  94         osc->hw.init = &init;
  95
  96         ret = devm_clk_hw_register(&pdev->dev, &osc->hw);
  97         if (ret < 0)
  98                 return ret;
  99
 100         devm_of_clk_add_hw_provider(&pdev->dev, of_clk_hw_simple_get, &osc->hw);
 101         clk_hw_set_rate_range(&osc->hw, osc->rate_min, osc->rate_max);
 102
 103         dev_dbg(&pdev->dev, "Registered clock '%s'\n", init.name);
 104
 105         return 0;
 106 }
 107
 108 static const struct of_device_id vexpress_osc_of_match[] = {
 109         { .compatible = "arm,vexpress-osc", },
 110         {}
 111 };
 112 MODULE_DEVICE_TABLE(of, vexpress_osc_of_match);
 113
 114 static struct platform_driver vexpress_osc_driver = {
 115         .driver = {
 116                 .name = "vexpress-osc",
 117                 .of_match_table = vexpress_osc_of_match,
 118         },
 119         .probe = vexpress_osc_probe,
 120 };
 121 module_platform_driver(vexpress_osc_driver);
 122 MODULE_LICENSE("GPL v2");