drivers/clk/clk-conf.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (C) 2014 Samsung Electronics Co., Ltd.
   4  * Sylwester Nawrocki <s.nawrocki@samsung.com>
   5  */
   6
   7 #include <linux/clk.h>
   8 #include <linux/clk-provider.h>
   9 #include <linux/clk/clk-conf.h>
  10 #include <linux/device.h>
  11 #include <linux/of.h>
  12 #include <linux/printk.h>
  13
  14 static int __set_clk_parents(struct device_node *node, bool clk_supplier)
  15 {
  16         struct of_phandle_args clkspec;
  17         int index, rc, num_parents;
  18         struct clk *clk, *pclk;
  19
  20         num_parents = of_count_phandle_with_args(node, "assigned-clock-parents",
  21                                                  "#clock-cells");
  22         if (num_parents == -EINVAL)
  23                 pr_err("clk: invalid value of clock-parents property at %pOF\n",
  24                        node);
  25
  26         for (index = 0; index < num_parents; index++) {
  27                 rc = of_parse_phandle_with_args(node, "assigned-clock-parents",
  28                                         "#clock-cells", index, &clkspec);
  29                 if (rc < 0) {
  30                         /* skip empty (null) phandles */
  31                         if (rc == -ENOENT)
  32                                 continue;
  33                         else
  34                                 return rc;
  35                 }
  36                 if (clkspec.np == node && !clk_supplier) {
  37                         of_node_put(clkspec.np);
  38                         return 0;
  39                 }
  40                 pclk = of_clk_get_from_provider(&clkspec);
  41                 of_node_put(clkspec.np);
  42                 if (IS_ERR(pclk)) {
  43                         if (PTR_ERR(pclk) != -EPROBE_DEFER)
  44                                 pr_warn("clk: couldn't get parent clock %d for %pOF\n",
  45                                         index, node);
  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                         of_node_put(clkspec.np);
  55                         rc = 0;
  56                         goto err;
  57                 }
  58                 clk = of_clk_get_from_provider(&clkspec);
  59                 of_node_put(clkspec.np);
  60                 if (IS_ERR(clk)) {
  61                         if (PTR_ERR(clk) != -EPROBE_DEFER)
  62                                 pr_warn("clk: couldn't get assigned clock %d for %pOF\n",
  63                                         index, node);
  64                         rc = PTR_ERR(clk);
  65                         goto err;
  66                 }
  67
  68                 rc = clk_set_parent(clk, pclk);
  69                 if (rc < 0)
  70                         pr_err("clk: failed to reparent %s to %s: %d\n",
  71                                __clk_get_name(clk), __clk_get_name(pclk), rc);
  72                 clk_put(clk);
  73                 clk_put(pclk);
  74         }
  75         return 0;
  76 err:
  77         clk_put(pclk);
  78         return rc;
  79 }
  80
  81 static int __set_clk_rates(struct device_node *node, bool clk_supplier)
  82 {
  83         struct of_phandle_args clkspec;
  84         struct property *prop;
  85         const __be32 *cur;
  86         int rc, index = 0;
  87         struct clk *clk;
  88         u32 rate;
  89
  90         of_property_for_each_u32(node, "assigned-clock-rates", prop, cur, rate) {
  91                 if (rate) {
  92                         rc = of_parse_phandle_with_args(node, "assigned-clocks",
  93                                         "#clock-cells", index, &clkspec);
  94                         if (rc < 0) {
  95                                 /* skip empty (null) phandles */
  96                                 if (rc == -ENOENT)
  97                                         continue;
  98                                 else
  99                                         return rc;
 100                         }
 101                         if (clkspec.np == node && !clk_supplier) {
 102                                 of_node_put(clkspec.np);
 103                                 return 0;
 104                         }
 105
 106                         clk = of_clk_get_from_provider(&clkspec);
 107                         of_node_put(clkspec.np);
 108                         if (IS_ERR(clk)) {
 109                                 if (PTR_ERR(clk) != -EPROBE_DEFER)
 110                                         pr_warn("clk: couldn't get clock %d for %pOF\n",
 111                                                 index, node);
 112                                 return PTR_ERR(clk);
 113                         }
 114
 115                         rc = clk_set_rate(clk, rate);
 116                         if (rc < 0)
 117                                 pr_err("clk: couldn't set %s clk rate to %u (%d), current rate: %lu\n",
 118                                        __clk_get_name(clk), rate, rc,
 119                                        clk_get_rate(clk));
 120                         clk_put(clk);
 121                 }
 122                 index++;
 123         }
 124         return 0;
 125 }
 126
 127 /**
 128  * of_clk_set_defaults() - parse and set assigned clocks configuration
 129  * @node: device node to apply clock settings for
 130  * @clk_supplier: true if clocks supplied by @node should also be considered
 131  *
 132  * This function parses 'assigned-{clocks/clock-parents/clock-rates}' properties
 133  * and sets any specified clock parents and rates. The @clk_supplier argument
 134  * should be set to true if @node may be also a clock supplier of any clock
 135  * listed in its 'assigned-clocks' or 'assigned-clock-parents' properties.
 136  * If @clk_supplier is false the function exits returning 0 as soon as it
 137  * determines the @node is also a supplier of any of the clocks.
 138  */
 139 int of_clk_set_defaults(struct device_node *node, bool clk_supplier)
 140 {
 141         int rc;
 142
 143         if (!node)
 144                 return 0;
 145
 146         rc = __set_clk_parents(node, clk_supplier);
 147         if (rc < 0)
 148                 return rc;
 149
 150         return __set_clk_rates(node, clk_supplier);
 151 }
 152 EXPORT_SYMBOL_GPL(of_clk_set_defaults);