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 18 /* 19 * DOC: basic fixed-rate clock that cannot gate 20 * 21 * Traits of this clock: 22 * prepare - clk_(un)prepare only ensures parents are prepared 23 * enable - clk_enable only ensures parents are enabled 24 * rate - rate is always a fixed value. No clk_set_rate support 25 * parent - fixed parent. No clk_set_parent support 26 */ 27 28 #define to_clk_fixed_rate(_hw) container_of(_hw, struct clk_fixed_rate, hw) 29 30 static unsigned long clk_fixed_rate_recalc_rate(struct clk_hw *hw, 31 unsigned long parent_rate) 32 { 33 return to_clk_fixed_rate(hw)->fixed_rate; 34 } 35 EXPORT_SYMBOL_GPL(clk_fixed_rate_recalc_rate); 36 37 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 struct clk *clk_register_fixed_rate(struct device *dev, const char *name, 43 const char *parent_name, unsigned long flags, 44 unsigned long fixed_rate) 45 { 46 struct clk_fixed_rate *fixed; 47 char **parent_names = NULL; 48 u8 len; 49 50 fixed = kzalloc(sizeof(struct clk_fixed_rate), GFP_KERNEL); 51 52 if (!fixed) { 53 pr_err("%s: could not allocate fixed clk\n", __func__); 54 return ERR_PTR(-ENOMEM); 55 } 56 57 /* struct clk_fixed_rate assignments */ 58 fixed->fixed_rate = fixed_rate; 59 60 if (parent_name) { 61 parent_names = kmalloc(sizeof(char *), GFP_KERNEL); 62 63 if (! parent_names) 64 goto out; 65 66 len = sizeof(char) * strlen(parent_name); 67 68 parent_names[0] = kmalloc(len, GFP_KERNEL); 69 70 if (!parent_names[0]) 71 goto out; 72 73 strncpy(parent_names[0], parent_name, len); 74 } 75 76 out: 77 return clk_register(dev, name, 78 &clk_fixed_rate_ops, &fixed->hw, 79 parent_names, 80 (parent_name ? 1 : 0), 81 flags); 82 } 83