1 /* 2 * Copyright (C) 2013 Boris BREZILLON <b.brezillon@overkiz.com> 3 * 4 * This program is free software; you can redistribute it and/or modify 5 * it under the terms of the GNU General Public License as published by 6 * the Free Software Foundation; either version 2 of the License, or 7 * (at your option) any later version. 8 * 9 */ 10 11 #include <linux/clk-provider.h> 12 #include <linux/clkdev.h> 13 #include <linux/clk/at91_pmc.h> 14 #include <linux/of.h> 15 #include <linux/of_address.h> 16 #include <linux/io.h> 17 18 #include "pmc.h" 19 20 #define SYSTEM_MAX_ID 31 21 22 #define SYSTEM_MAX_NAME_SZ 32 23 24 #define to_clk_system(hw) container_of(hw, struct clk_system, hw) 25 struct clk_system { 26 struct clk_hw hw; 27 struct at91_pmc *pmc; 28 u8 id; 29 }; 30 31 static int clk_system_enable(struct clk_hw *hw) 32 { 33 struct clk_system *sys = to_clk_system(hw); 34 struct at91_pmc *pmc = sys->pmc; 35 36 pmc_write(pmc, AT91_PMC_SCER, 1 << sys->id); 37 return 0; 38 } 39 40 static void clk_system_disable(struct clk_hw *hw) 41 { 42 struct clk_system *sys = to_clk_system(hw); 43 struct at91_pmc *pmc = sys->pmc; 44 45 pmc_write(pmc, AT91_PMC_SCDR, 1 << sys->id); 46 } 47 48 static int clk_system_is_enabled(struct clk_hw *hw) 49 { 50 struct clk_system *sys = to_clk_system(hw); 51 struct at91_pmc *pmc = sys->pmc; 52 53 return !!(pmc_read(pmc, AT91_PMC_SCSR) & (1 << sys->id)); 54 } 55 56 static const struct clk_ops system_ops = { 57 .enable = clk_system_enable, 58 .disable = clk_system_disable, 59 .is_enabled = clk_system_is_enabled, 60 }; 61 62 static struct clk * __init 63 at91_clk_register_system(struct at91_pmc *pmc, const char *name, 64 const char *parent_name, u8 id) 65 { 66 struct clk_system *sys; 67 struct clk *clk = NULL; 68 struct clk_init_data init; 69 70 if (!parent_name || id > SYSTEM_MAX_ID) 71 return ERR_PTR(-EINVAL); 72 73 sys = kzalloc(sizeof(*sys), GFP_KERNEL); 74 if (!sys) 75 return ERR_PTR(-ENOMEM); 76 77 init.name = name; 78 init.ops = &system_ops; 79 init.parent_names = &parent_name; 80 init.num_parents = 1; 81 /* 82 * CLK_IGNORE_UNUSED is used to avoid ddrck switch off. 83 * TODO : we should implement a driver supporting at91 ddr controller 84 * (see drivers/memory) which would request and enable the ddrck clock. 85 * When this is done we will be able to remove CLK_IGNORE_UNUSED flag. 86 */ 87 init.flags = CLK_IGNORE_UNUSED; 88 89 sys->id = id; 90 sys->hw.init = &init; 91 sys->pmc = pmc; 92 93 clk = clk_register(NULL, &sys->hw); 94 if (IS_ERR(clk)) 95 kfree(sys); 96 97 return clk; 98 } 99 100 static void __init 101 of_at91_clk_sys_setup(struct device_node *np, struct at91_pmc *pmc) 102 { 103 int num; 104 u32 id; 105 struct clk *clk; 106 const char *name; 107 struct device_node *sysclknp; 108 const char *parent_name; 109 110 num = of_get_child_count(np); 111 if (num > (SYSTEM_MAX_ID + 1)) 112 return; 113 114 for_each_child_of_node(np, sysclknp) { 115 if (of_property_read_u32(sysclknp, "reg", &id)) 116 continue; 117 118 if (of_property_read_string(np, "clock-output-names", &name)) 119 name = sysclknp->name; 120 121 parent_name = of_clk_get_parent_name(sysclknp, 0); 122 123 clk = at91_clk_register_system(pmc, name, parent_name, id); 124 if (IS_ERR(clk)) 125 continue; 126 127 of_clk_add_provider(sysclknp, of_clk_src_simple_get, clk); 128 } 129 } 130 131 void __init of_at91rm9200_clk_sys_setup(struct device_node *np, 132 struct at91_pmc *pmc) 133 { 134 of_at91_clk_sys_setup(np, pmc); 135 } 136