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 %pOF\n",
  27                        node);
  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                         of_node_put(clkspec.np);
  41                         return 0;
  42                 }
  43                 pclk = of_clk_get_from_provider(&clkspec);
  44                 of_node_put(clkspec.np);
  45                 if (IS_ERR(pclk)) {
  46                         if (PTR_ERR(pclk) != -EPROBE_DEFER)
  47                                 pr_warn("clk: couldn't get parent clock %d for %pOF\n",
  48                                         index, node);
  49                         return PTR_ERR(pclk);
  50                 }
  51
  52                 rc = of_parse_phandle_with_args(node, "assigned-clocks",
  53                                         "#clock-cells", index, &clkspec);
  54                 if (rc < 0)
  55                         goto err;
  56                 if (clkspec.np == node && !clk_supplier) {
  57                         of_node_put(clkspec.np);
  58                         rc = 0;
  59                         goto err;
  60                 }
  61                 clk = of_clk_get_from_provider(&clkspec);
  62                 of_node_put(clkspec.np);
  63                 if (IS_ERR(clk)) {
  64                         if (PTR_ERR(clk) != -EPROBE_DEFER)
  65                                 pr_warn("clk: couldn't get assigned clock %d for %pOF\n",
  66                                         index, node);
  67                         rc = PTR_ERR(clk);
  68                         goto err;
  69                 }
  70
  71                 rc = clk_set_parent(clk, pclk);
  72                 if (rc < 0)
  73                         pr_err("clk: failed to reparent %s to %s: %d\n",
  74                                __clk_get_name(clk), __clk_get_name(pclk), rc);
  75                 clk_put(clk);
  76                 clk_put(pclk);
  77         }
  78         return 0;
  79 err:
  80         clk_put(pclk);
  81         return rc;
  82 }
  83
  84 static int __set_clk_rates(struct device_node *node, bool clk_supplier)
  85 {
  86         struct of_phandle_args clkspec;
  87         struct property *prop;
  88         const __be32 *cur;
  89         int rc, index = 0;
  90         struct clk *clk;
  91         u32 rate;
  92
  93         of_property_for_each_u32(node, "assigned-clock-rates", prop, cur, rate) {
  94                 if (rate) {
  95                         rc = of_parse_phandle_with_args(node, "assigned-clocks",
  96                                         "#clock-cells", index, &clkspec);
  97                         if (rc < 0) {
  98                                 /* skip empty (null) phandles */
  99                                 if (rc == -ENOENT)
 100                                         continue;
 101                                 else
 102                                         return rc;
 103                         }
 104                         if (clkspec.np == node && !clk_supplier) {
 105                                 of_node_put(clkspec.np);
 106                                 return 0;
 107                         }
 108
 109                         clk = of_clk_get_from_provider(&clkspec);
 110                         of_node_put(clkspec.np);
 111                         if (IS_ERR(clk)) {
 112                                 if (PTR_ERR(clk) != -EPROBE_DEFER)
 113                                         pr_warn("clk: couldn't get clock %d for %pOF\n",
 114                                                 index, node);
 115                                 return PTR_ERR(clk);
 116                         }
 117
 118                         rc = clk_set_rate(clk, rate);
 119                         if (rc < 0)
 120                                 pr_err("clk: couldn't set %s clk rate to %u (%d), current rate: %lu\n",
 121                                        __clk_get_name(clk), rate, rc,
 122                                        clk_get_rate(clk));
 123                         clk_put(clk);
 124                 }
 125                 index++;
 126         }
 127         return 0;
 128 }
 129
 130 /**
 131  * of_clk_set_defaults() - parse and set assigned clocks configuration
 132  * @node: device node to apply clock settings for
 133  * @clk_supplier: true if clocks supplied by @node should also be considered
 134  *
 135  * This function parses 'assigned-{clocks/clock-parents/clock-rates}' properties
 136  * and sets any specified clock parents and rates. The @clk_supplier argument
 137  * should be set to true if @node may be also a clock supplier of any clock
 138  * listed in its 'assigned-clocks' or 'assigned-clock-parents' properties.
 139  * If @clk_supplier is false the function exits returning 0 as soon as it
 140  * determines the @node is also a supplier of any of the clocks.
 141  */
 142 int of_clk_set_defaults(struct device_node *node, bool clk_supplier)
 143 {
 144         int rc;
 145
 146         if (!node)
 147                 return 0;
 148
 149         rc = __set_clk_parents(node, clk_supplier);
 150         if (rc < 0)
 151                 return rc;
 152
 153         return __set_clk_rates(node, clk_supplier);
 154 }
 155 EXPORT_SYMBOL_GPL(of_clk_set_defaults);