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
  17 static 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;
  72 err:
  73         clk_put(pclk);
  74         return rc;
  75 }
  76
  77 static 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  */
 131 int 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 }
 144 EXPORT_SYMBOL_GPL(of_clk_set_defaults);