LXR linux/drivers/clk/clk-conf.c

   1/*
   2 * Copyright (C) 2014 Samsung Electronics Co., Ltd.
   3 * Sylwester Nawrocki <s.nawrocki@samsung.com>
   4 *
   5 * This program is free software; you can redistribute it and/or modify
   6 * it under the terms of the GNU General Public License version 2 as
   7 * published by the Free Software Foundation.
   8 */
   9
  10#include <linux/clk.h>
  11#include <linux/clk-provider.h>
  12#include <linux/clk/clk-conf.h>
  13#include <linux/device.h>
  14#include <linux/of.h>
  15#include <linux/printk.h>
  16
  17static int __set_clk_parents(struct device_node *node, bool clk_supplier)
  18{
  19        struct of_phandle_args clkspec;
  20        int index, rc, num_parents;
  21        struct clk *clk, *pclk;
  22
  23        num_parents = of_count_phandle_with_args(node, "assigned-clock-parents",
  24                                                 "#clock-cells");
  25        if (num_parents == -EINVAL)
  26                pr_err("clk: invalid value of clock-parents property at %s\n",
  27                       node->full_name);
  28
  29        for (index = 0; index < num_parents; index++) {
  30                rc = of_parse_phandle_with_args(node, "assigned-clock-parents",
  31                                        "#clock-cells", index, &clkspec);
  32                if (rc < 0) {
  33                        /* skip empty (null) phandles */
  34                        if (rc == -ENOENT)
  35                                continue;
  36                        else
  37                                return rc;
  38                }
  39                if (clkspec.np == node && !clk_supplier)
  40                        return 0;
  41                pclk = of_clk_get_from_provider(&clkspec);
  42                if (IS_ERR(pclk)) {
  43                        pr_warn("clk: couldn't get parent clock %d for %s\n",
  44                                index, node->full_name);
  45                        return PTR_ERR(pclk);
  46                }
  47
  48                rc = of_parse_phandle_with_args(node, "assigned-clocks",
  49                                        "#clock-cells", index, &clkspec);
  50                if (rc < 0)
  51                        goto err;
  52                if (clkspec.np == node && !clk_supplier) {
  53                        rc = 0;
  54                        goto err;
  55                }
  56                clk = of_clk_get_from_provider(&clkspec);
  57                if (IS_ERR(clk)) {
  58                        pr_warn("clk: couldn't get assigned clock %d for %s\n",
  59                                index, node->full_name);
  60                        rc = PTR_ERR(clk);
  61                        goto err;
  62                }
  63
  64                rc = clk_set_parent(clk, pclk);
  65                if (rc < 0)
  66                        pr_err("clk: failed to reparent %s to %s: %d\n",
  67                               __clk_get_name(clk), __clk_get_name(pclk), rc);
  68                clk_put(clk);
  69                clk_put(pclk);
  70        }
  71        return 0;
  72err:
  73        clk_put(pclk);
  74        return rc;
  75}
  76
  77static int __set_clk_rates(struct device_node *node, bool clk_supplier)
  78{
  79        struct of_phandle_args clkspec;
  80        struct property *prop;
  81        const __be32 *cur;
  82        int rc, index = 0;
  83        struct clk *clk;
  84        u32 rate;
  85
  86        of_property_for_each_u32(node, "assigned-clock-rates", prop, cur, rate) {
  87                if (rate) {
  88                        rc = of_parse_phandle_with_args(node, "assigned-clocks",
  89                                        "#clock-cells", index, &clkspec);
  90                        if (rc < 0) {
  91                                /* skip empty (null) phandles */
  92                                if (rc == -ENOENT)
  93                                        continue;
  94                                else
  95                                        return rc;
  96                        }
  97                        if (clkspec.np == node && !clk_supplier)
  98                                return 0;
  99
 100                        clk = of_clk_get_from_provider(&clkspec);
 101                        if (IS_ERR(clk)) {
 102                                pr_warn("clk: couldn't get clock %d for %s\n",
 103                                        index, node->full_name);
 104                                return PTR_ERR(clk);
 105                        }
 106
 107                        rc = clk_set_rate(clk, rate);
 108                        if (rc < 0)
 109                                pr_err("clk: couldn't set %s clk rate to %d (%d), current rate: %ld\n",
 110                                       __clk_get_name(clk), rate, rc,
 111                                       clk_get_rate(clk));
 112                        clk_put(clk);
 113                }
 114                index++;
 115        }
 116        return 0;
 117}
 118
 119/**
 120 * of_clk_set_defaults() - parse and set assigned clocks configuration
 121 * @node: device node to apply clock settings for
 122 * @clk_supplier: true if clocks supplied by @node should also be considered
 123 *
 124 * This function parses 'assigned-{clocks/clock-parents/clock-rates}' properties
 125 * and sets any specified clock parents and rates. The @clk_supplier argument
 126 * should be set to true if @node may be also a clock supplier of any clock
 127 * listed in its 'assigned-clocks' or 'assigned-clock-parents' properties.
 128 * If @clk_supplier is false the function exits returning 0 as soon as it
 129 * determines the @node is also a supplier of any of the clocks.
 130 */
 131int of_clk_set_defaults(struct device_node *node, bool clk_supplier)
 132{
 133        int rc;
 134
 135        if (!node)
 136                return 0;
 137
 138        rc = __set_clk_parents(node, clk_supplier);
 139        if (rc < 0)
 140                return rc;
 141
 142        return __set_clk_rates(node, clk_supplier);
 143}
 144EXPORT_SYMBOL_GPL(of_clk_set_defaults);
 145