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/of.h>
  11 #include <linux/platform_device.h>
  12 #include <linux/slab.h>
  13 #include <linux/vexpress.h>
  14
  15 struct vexpress_osc {
  16         struct regmap *reg;
  17         struct clk_hw hw;
  18         unsigned long rate_min;
  19         unsigned long rate_max;
  20 };
  21
  22 #define to_vexpress_osc(osc) container_of(osc, struct vexpress_osc, hw)
  23
  24 static unsigned long vexpress_osc_recalc_rate(struct clk_hw *hw,
  25                 unsigned long parent_rate)
  26 {
  27         struct vexpress_osc *osc = to_vexpress_osc(hw);
  28         u32 rate;
  29
  30         regmap_read(osc->reg, 0, &rate);
  31
  32         return rate;
  33 }
  34
  35 static long vexpress_osc_round_rate(struct clk_hw *hw, unsigned long rate,
  36                 unsigned long *parent_rate)
  37 {
  38         struct vexpress_osc *osc = to_vexpress_osc(hw);
  39
  40         if (osc->rate_min && rate < osc->rate_min)
  41                 rate = osc->rate_min;
  42
  43         if (osc->rate_max && rate > osc->rate_max)
  44                 rate = osc->rate_max;
  45
  46         return rate;
  47 }
  48
  49 static int vexpress_osc_set_rate(struct clk_hw *hw, unsigned long rate,
  50                 unsigned long parent_rate)
  51 {
  52         struct vexpress_osc *osc = to_vexpress_osc(hw);
  53
  54         return regmap_write(osc->reg, 0, rate);
  55 }
  56
  57 static const struct clk_ops vexpress_osc_ops = {
  58         .recalc_rate = vexpress_osc_recalc_rate,
  59         .round_rate = vexpress_osc_round_rate,
  60         .set_rate = vexpress_osc_set_rate,
  61 };
  62
  63
  64 static int vexpress_osc_probe(struct platform_device *pdev)
  65 {
  66         struct clk_init_data init;
  67         struct vexpress_osc *osc;
  68         struct clk *clk;
  69         u32 range[2];
  70
  71         osc = devm_kzalloc(&pdev->dev, sizeof(*osc), GFP_KERNEL);
  72         if (!osc)
  73                 return -ENOMEM;
  74
  75         osc->reg = devm_regmap_init_vexpress_config(&pdev->dev);
  76         if (IS_ERR(osc->reg))
  77                 return PTR_ERR(osc->reg);
  78
  79         if (of_property_read_u32_array(pdev->dev.of_node, "freq-range", range,
  80                         ARRAY_SIZE(range)) == 0) {
  81                 osc->rate_min = range[0];
  82                 osc->rate_max = range[1];
  83         }
  84
  85         if (of_property_read_string(pdev->dev.of_node, "clock-output-names",
  86                         &init.name) != 0)
  87                 init.name = dev_name(&pdev->dev);
  88
  89         init.ops = &vexpress_osc_ops;
  90         init.flags = 0;
  91         init.num_parents = 0;
  92
  93         osc->hw.init = &init;
  94
  95         clk = clk_register(NULL, &osc->hw);
  96         if (IS_ERR(clk))
  97                 return PTR_ERR(clk);
  98
  99         of_clk_add_provider(pdev->dev.of_node, of_clk_src_simple_get, clk);
 100         clk_hw_set_rate_range(&osc->hw, osc->rate_min, osc->rate_max);
 101
 102         dev_dbg(&pdev->dev, "Registered clock '%s'\n", init.name);
 103
 104         return 0;
 105 }
 106
 107 static const struct of_device_id vexpress_osc_of_match[] = {
 108         { .compatible = "arm,vexpress-osc", },
 109         {}
 110 };
 111
 112 static struct platform_driver vexpress_osc_driver = {
 113         .driver = {
 114                 .name = "vexpress-osc",
 115                 .of_match_table = vexpress_osc_of_match,
 116         },
 117         .probe = vexpress_osc_probe,
 118 };
 119
 120 static int __init vexpress_osc_init(void)
 121 {
 122         return platform_driver_register(&vexpress_osc_driver);
 123 }
 124 core_initcall(vexpress_osc_init);