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