LXR linux/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#define pr_fmt(fmt) "vexpress-osc: " fmt
  15
  16#include <linux/clkdev.h>
  17#include <linux/clk-provider.h>
  18#include <linux/err.h>
  19#include <linux/of.h>
  20#include <linux/platform_device.h>
  21#include <linux/slab.h>
  22#include <linux/vexpress.h>
  23
  24struct vexpress_osc {
  25        struct vexpress_config_func *func;
  26        struct clk_hw hw;
  27        unsigned long rate_min;
  28        unsigned long rate_max;
  29};
  30
  31#define to_vexpress_osc(osc) container_of(osc, struct vexpress_osc, hw)
  32
  33static unsigned long vexpress_osc_recalc_rate(struct clk_hw *hw,
  34                unsigned long parent_rate)
  35{
  36        struct vexpress_osc *osc = to_vexpress_osc(hw);
  37        u32 rate;
  38
  39        vexpress_config_read(osc->func, 0, &rate);
  40
  41        return rate;
  42}
  43
  44static long vexpress_osc_round_rate(struct clk_hw *hw, unsigned long rate,
  45                unsigned long *parent_rate)
  46{
  47        struct vexpress_osc *osc = to_vexpress_osc(hw);
  48
  49        if (WARN_ON(osc->rate_min && rate < osc->rate_min))
  50                rate = osc->rate_min;
  51
  52        if (WARN_ON(osc->rate_max && rate > osc->rate_max))
  53                rate = osc->rate_max;
  54
  55        return rate;
  56}
  57
  58static int vexpress_osc_set_rate(struct clk_hw *hw, unsigned long rate,
  59                unsigned long parent_rate)
  60{
  61        struct vexpress_osc *osc = to_vexpress_osc(hw);
  62
  63        return vexpress_config_write(osc->func, 0, rate);
  64}
  65
  66static struct clk_ops vexpress_osc_ops = {
  67        .recalc_rate = vexpress_osc_recalc_rate,
  68        .round_rate = vexpress_osc_round_rate,
  69        .set_rate = vexpress_osc_set_rate,
  70};
  71
  72
  73struct clk * __init vexpress_osc_setup(struct device *dev)
  74{
  75        struct clk_init_data init;
  76        struct vexpress_osc *osc = kzalloc(sizeof(*osc), GFP_KERNEL);
  77
  78        if (!osc)
  79                return NULL;
  80
  81        osc->func = vexpress_config_func_get_by_dev(dev);
  82        if (!osc->func) {
  83                kfree(osc);
  84                return NULL;
  85        }
  86
  87        init.name = dev_name(dev);
  88        init.ops = &vexpress_osc_ops;
  89        init.flags = CLK_IS_ROOT;
  90        init.num_parents = 0;
  91        osc->hw.init = &init;
  92
  93        return clk_register(NULL, &osc->hw);
  94}
  95
  96void __init vexpress_osc_of_setup(struct device_node *node)
  97{
  98        struct clk_init_data init;
  99        struct vexpress_osc *osc;
 100        struct clk *clk;
 101        u32 range[2];
 102
 103        osc = kzalloc(sizeof(*osc), GFP_KERNEL);
 104        if (!osc)
 105                goto error;
 106
 107        osc->func = vexpress_config_func_get_by_node(node);
 108        if (!osc->func) {
 109                pr_err("Failed to obtain config func for node '%s'!\n",
 110                                node->name);
 111                goto error;
 112        }
 113
 114        if (of_property_read_u32_array(node, "freq-range", range,
 115                        ARRAY_SIZE(range)) == 0) {
 116                osc->rate_min = range[0];
 117                osc->rate_max = range[1];
 118        }
 119
 120        of_property_read_string(node, "clock-output-names", &init.name);
 121        if (!init.name)
 122                init.name = node->name;
 123
 124        init.ops = &vexpress_osc_ops;
 125        init.flags = CLK_IS_ROOT;
 126        init.num_parents = 0;
 127
 128        osc->hw.init = &init;
 129
 130        clk = clk_register(NULL, &osc->hw);
 131        if (IS_ERR(clk)) {
 132                pr_err("Failed to register clock '%s'!\n", init.name);
 133                goto error;
 134        }
 135
 136        of_clk_add_provider(node, of_clk_src_simple_get, clk);
 137
 138        pr_debug("Registered clock '%s'\n", init.name);
 139
 140        return;
 141
 142error:
 143        if (osc->func)
 144                vexpress_config_func_put(osc->func);
 145        kfree(osc);
 146}
 147