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