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 parent 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 clock rate: %d\n", 110 __clk_get_name(clk), rc); 111 clk_put(clk); 112 } 113 index++; 114 } 115 return 0; 116 } 117 118 /** 119 * of_clk_set_defaults() - parse and set assigned clocks configuration 120 * @node: device node to apply clock settings for 121 * @clk_supplier: true if clocks supplied by @node should also be considered 122 * 123 * This function parses 'assigned-{clocks/clock-parents/clock-rates}' properties 124 * and sets any specified clock parents and rates. The @clk_supplier argument 125 * should be set to true if @node may be also a clock supplier of any clock 126 * listed in its 'assigned-clocks' or 'assigned-clock-parents' properties. 127 * If @clk_supplier is false the function exits returnning 0 as soon as it 128 * determines the @node is also a supplier of any of the clocks. 129 */ 130 int of_clk_set_defaults(struct device_node *node, bool clk_supplier) 131 { 132 int rc; 133 134 if (!node) 135 return 0; 136 137 rc = __set_clk_parents(node, clk_supplier); 138 if (rc < 0) 139 return rc; 140 141 return __set_clk_rates(node, clk_supplier); 142 } 143 EXPORT_SYMBOL_GPL(of_clk_set_defaults); 144