1 /* 2 * Copyright (C) 2010-2011 Canonical Ltd <jeremy.kerr@canonical.com> 3 * Copyright (C) 2011-2012 Mike Turquette, Linaro Ltd <mturquette@linaro.org> 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 * Fixed rate clock implementation 10 */ 11 12 #include <linux/clk-provider.h> 13 #include <linux/module.h> 14 #include <linux/slab.h> 15 #include <linux/io.h> 16 #include <linux/err.h> 17 #include <linux/of.h> 18 19 /* 20 * DOC: basic fixed-rate clock that cannot gate 21 * 22 * Traits of this clock: 23 * prepare - clk_(un)prepare only ensures parents are prepared 24 * enable - clk_enable only ensures parents are enabled 25 * rate - rate is always a fixed value. No clk_set_rate support 26 * parent - fixed parent. No clk_set_parent support 27 */ 28 29 #define to_clk_fixed_rate(_hw) container_of(_hw, struct clk_fixed_rate, hw) 30 31 static unsigned long clk_fixed_rate_recalc_rate(struct clk_hw *hw, 32 unsigned long parent_rate) 33 { 34 return to_clk_fixed_rate(hw)->fixed_rate; 35 } 36 37 const struct clk_ops clk_fixed_rate_ops = { 38 .recalc_rate = clk_fixed_rate_recalc_rate, 39 }; 40 EXPORT_SYMBOL_GPL(clk_fixed_rate_ops); 41 42 /** 43 * clk_register_fixed_rate - register fixed-rate clock with the clock framework 44 * @dev: device that is registering this clock 45 * @name: name of this clock 46 * @parent_name: name of clock's parent 47 * @flags: framework-specific flags 48 * @fixed_rate: non-adjustable clock rate 49 */ 50 struct clk *clk_register_fixed_rate(struct device *dev, const char *name, 51 const char *parent_name, unsigned long flags, 52 unsigned long fixed_rate) 53 { 54 struct clk_fixed_rate *fixed; 55 struct clk *clk; 56 struct clk_init_data init; 57 58 /* allocate fixed-rate clock */ 59 fixed = kzalloc(sizeof(struct clk_fixed_rate), GFP_KERNEL); 60 if (!fixed) { 61 pr_err("%s: could not allocate fixed clk\n", __func__); 62 return ERR_PTR(-ENOMEM); 63 } 64 65 init.name = name; 66 init.ops = &clk_fixed_rate_ops; 67 init.flags = flags | CLK_IS_BASIC; 68 init.parent_names = (parent_name ? &parent_name: NULL); 69 init.num_parents = (parent_name ? 1 : 0); 70 71 /* struct clk_fixed_rate assignments */ 72 fixed->fixed_rate = fixed_rate; 73 fixed->hw.init = &init; 74 75 /* register the clock */ 76 clk = clk_register(dev, &fixed->hw); 77 78 if (IS_ERR(clk)) 79 kfree(fixed); 80 81 return clk; 82 } 83 84 #ifdef CONFIG_OF 85 /** 86 * of_fixed_clk_setup() - Setup function for simple fixed rate clock 87 */ 88 void of_fixed_clk_setup(struct device_node *node) 89 { 90 struct clk *clk; 91 const char *clk_name = node->name; 92 u32 rate; 93 94 if (of_property_read_u32(node, "clock-frequency", &rate)) 95 return; 96 97 of_property_read_string(node, "clock-output-names", &clk_name); 98 99 clk = clk_register_fixed_rate(NULL, clk_name, NULL, CLK_IS_ROOT, rate); 100 if (!IS_ERR(clk)) 101 of_clk_add_provider(node, of_clk_src_simple_get, clk); 102 } 103 EXPORT_SYMBOL_GPL(of_fixed_clk_setup); 104 CLK_OF_DECLARE(fixed_clk, "fixed-clock", of_fixed_clk_setup); 105 #endif 106