drivers/clk/clk-conf.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (C) 2014 Samsung Electronics Co., Ltd.
   4  * Sylwester Nawrocki <[email protected]>
   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         int rc, index = 0;
  85         struct clk *clk;
  86         u32 rate;
  87
  88         of_property_for_each_u32(node, "assigned-clock-rates", rate) {
  89                 if (rate) {
  90                         rc = of_parse_phandle_with_args(node, "assigned-clocks",
  91                                         "#clock-cells", index, &clkspec);
  92                         if (rc < 0) {
  93                                 /* skip empty (null) phandles */
  94                                 if (rc == -ENOENT)
  95                                         continue;
  96                                 else
  97                                         return rc;
  98                         }
  99                         if (clkspec.np == node && !clk_supplier) {
 100                                 of_node_put(clkspec.np);
 101                                 return 0;
 102                         }
 103
 104                         clk = of_clk_get_from_provider(&clkspec);
 105                         of_node_put(clkspec.np);
 106                         if (IS_ERR(clk)) {
 107                                 if (PTR_ERR(clk) != -EPROBE_DEFER)
 108                                         pr_warn("clk: couldn't get clock %d for %pOF\n",
 109                                                 index, node);
 110                                 return PTR_ERR(clk);
 111                         }
 112
 113                         rc = clk_set_rate(clk, rate);
 114                         if (rc < 0)
 115                                 pr_err("clk: couldn't set %s clk rate to %u (%d), current rate: %lu\n",
 116                                        __clk_get_name(clk), rate, rc,
 117                                        clk_get_rate(clk));
 118                         clk_put(clk);
 119                 }
 120                 index++;
 121         }
 122         return 0;
 123 }
 124
 125 /**
 126  * of_clk_set_defaults() - parse and set assigned clocks configuration
 127  * @node: device node to apply clock settings for
 128  * @clk_supplier: true if clocks supplied by @node should also be considered
 129  *
 130  * This function parses 'assigned-{clocks/clock-parents/clock-rates}' properties
 131  * and sets any specified clock parents and rates. The @clk_supplier argument
 132  * should be set to true if @node may be also a clock supplier of any clock
 133  * listed in its 'assigned-clocks' or 'assigned-clock-parents' properties.
 134  * If @clk_supplier is false the function exits returning 0 as soon as it
 135  * determines the @node is also a supplier of any of the clocks.
 136  */
 137 int of_clk_set_defaults(struct device_node *node, bool clk_supplier)
 138 {
 139         int rc;
 140
 141         if (!node)
 142                 return 0;
 143
 144         rc = __set_clk_parents(node, clk_supplier);
 145         if (rc < 0)
 146                 return rc;
 147
 148         return __set_clk_rates(node, clk_supplier);
 149 }
 150 EXPORT_SYMBOL_GPL(of_clk_set_defaults);