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

   1 /*
   2  * This program is free software; you can redistribute it and/or modify
   3  * it under the terms of the GNU General Public License version 2 as
   4  * published by the Free Software Foundation.
   5  *
   6  * This program is distributed in the hope that it will be useful,
   7  * but WITHOUT ANY WARRANTY; without even the implied warranty of
   8  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   9  * GNU General Public License for more details.
  10  *
  11  * Copyright (C) 2012 ARM Limited
  12  */
  13
  14 #include <linux/clkdev.h>
  15 #include <linux/clk-provider.h>
  16 #include <linux/err.h>
  17 #include <linux/of.h>
  18 #include <linux/platform_device.h>
  19 #include <linux/slab.h>
  20 #include <linux/vexpress.h>
  21
  22 struct vexpress_osc {
  23         struct regmap *reg;
  24         struct clk_hw hw;
  25         unsigned long rate_min;
  26         unsigned long rate_max;
  27 };
  28
  29 #define to_vexpress_osc(osc) container_of(osc, struct vexpress_osc, hw)
  30
  31 static unsigned long vexpress_osc_recalc_rate(struct clk_hw *hw,
  32                 unsigned long parent_rate)
  33 {
  34         struct vexpress_osc *osc = to_vexpress_osc(hw);
  35         u32 rate;
  36
  37         regmap_read(osc->reg, 0, &rate);
  38
  39         return rate;
  40 }
  41
  42 static long vexpress_osc_round_rate(struct clk_hw *hw, unsigned long rate,
  43                 unsigned long *parent_rate)
  44 {
  45         struct vexpress_osc *osc = to_vexpress_osc(hw);
  46
  47         if (WARN_ON(osc->rate_min && rate < osc->rate_min))
  48                 rate = osc->rate_min;
  49
  50         if (WARN_ON(osc->rate_max && rate > osc->rate_max))
  51                 rate = osc->rate_max;
  52
  53         return rate;
  54 }
  55
  56 static int vexpress_osc_set_rate(struct clk_hw *hw, unsigned long rate,
  57                 unsigned long parent_rate)
  58 {
  59         struct vexpress_osc *osc = to_vexpress_osc(hw);
  60
  61         return regmap_write(osc->reg, 0, rate);
  62 }
  63
  64 static struct clk_ops vexpress_osc_ops = {
  65         .recalc_rate = vexpress_osc_recalc_rate,
  66         .round_rate = vexpress_osc_round_rate,
  67         .set_rate = vexpress_osc_set_rate,
  68 };
  69
  70
  71 static int vexpress_osc_probe(struct platform_device *pdev)
  72 {
  73         struct clk_lookup *cl = pdev->dev.platform_data; /* Non-DT lookup */
  74         struct clk_init_data init;
  75         struct vexpress_osc *osc;
  76         struct clk *clk;
  77         u32 range[2];
  78
  79         osc = devm_kzalloc(&pdev->dev, sizeof(*osc), GFP_KERNEL);
  80         if (!osc)
  81                 return -ENOMEM;
  82
  83         osc->reg = devm_regmap_init_vexpress_config(&pdev->dev);
  84         if (IS_ERR(osc->reg))
  85                 return PTR_ERR(osc->reg);
  86
  87         if (of_property_read_u32_array(pdev->dev.of_node, "freq-range", range,
  88                         ARRAY_SIZE(range)) == 0) {
  89                 osc->rate_min = range[0];
  90                 osc->rate_max = range[1];
  91         }
  92
  93         if (of_property_read_string(pdev->dev.of_node, "clock-output-names",
  94                         &init.name) != 0)
  95                 init.name = dev_name(&pdev->dev);
  96
  97         init.ops = &vexpress_osc_ops;
  98         init.flags = CLK_IS_ROOT;
  99         init.num_parents = 0;
 100
 101         osc->hw.init = &init;
 102
 103         clk = clk_register(NULL, &osc->hw);
 104         if (IS_ERR(clk))
 105                 return PTR_ERR(clk);
 106
 107         of_clk_add_provider(pdev->dev.of_node, of_clk_src_simple_get, clk);
 108
 109         /* Only happens for non-DT cases */
 110         if (cl) {
 111                 cl->clk = clk;
 112                 clkdev_add(cl);
 113         }
 114
 115         dev_dbg(&pdev->dev, "Registered clock '%s'\n", init.name);
 116
 117         return 0;
 118 }
 119
 120 static struct of_device_id vexpress_osc_of_match[] = {
 121         { .compatible = "arm,vexpress-osc", },
 122         {}
 123 };
 124
 125 static struct platform_driver vexpress_osc_driver = {
 126         .driver = {
 127                 .name = "vexpress-osc",
 128                 .of_match_table = vexpress_osc_of_match,
 129         },
 130         .probe = vexpress_osc_probe,
 131 };
 132
 133 static int __init vexpress_osc_init(void)
 134 {
 135         return platform_driver_register(&vexpress_osc_driver);
 136 }
 137 core_initcall(vexpress_osc_init);