1 /* 2 * This program is free software; you can redistribute it and/or modify 3 * it under the terms of the GNU General Public License version 2 as 4 * published by the Free Software Foundation. 5 * 6 * This program is distributed in the hope that it will be useful, 7 * but WITHOUT ANY WARRANTY; without even the implied warranty of 8 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 9 * GNU General Public License for more details. 10 * 11 * Copyright (C) 2013 ARM Limited 12 */ 13 14 #include <linux/amba/sp810.h> 15 #include <linux/slab.h> 16 #include <linux/clk.h> 17 #include <linux/clk-provider.h> 18 #include <linux/err.h> 19 #include <linux/of.h> 20 #include <linux/of_address.h> 21 22 #define to_clk_sp810_timerclken(_hw) \ 23 container_of(_hw, struct clk_sp810_timerclken, hw) 24 25 struct clk_sp810; 26 27 struct clk_sp810_timerclken { 28 struct clk_hw hw; 29 struct clk *clk; 30 struct clk_sp810 *sp810; 31 int channel; 32 }; 33 34 struct clk_sp810 { 35 struct device_node *node; 36 void __iomem *base; 37 spinlock_t lock; 38 struct clk_sp810_timerclken timerclken[4]; 39 }; 40 41 static u8 clk_sp810_timerclken_get_parent(struct clk_hw *hw) 42 { 43 struct clk_sp810_timerclken *timerclken = to_clk_sp810_timerclken(hw); 44 u32 val = readl(timerclken->sp810->base + SCCTRL); 45 46 return !!(val & (1 << SCCTRL_TIMERENnSEL_SHIFT(timerclken->channel))); 47 } 48 49 static int clk_sp810_timerclken_set_parent(struct clk_hw *hw, u8 index) 50 { 51 struct clk_sp810_timerclken *timerclken = to_clk_sp810_timerclken(hw); 52 struct clk_sp810 *sp810 = timerclken->sp810; 53 u32 val, shift = SCCTRL_TIMERENnSEL_SHIFT(timerclken->channel); 54 unsigned long flags = 0; 55 56 if (WARN_ON(index > 1)) 57 return -EINVAL; 58 59 spin_lock_irqsave(&sp810->lock, flags); 60 61 val = readl(sp810->base + SCCTRL); 62 val &= ~(1 << shift); 63 val |= index << shift; 64 writel(val, sp810->base + SCCTRL); 65 66 spin_unlock_irqrestore(&sp810->lock, flags); 67 68 return 0; 69 } 70 71 static const struct clk_ops clk_sp810_timerclken_ops = { 72 .get_parent = clk_sp810_timerclken_get_parent, 73 .set_parent = clk_sp810_timerclken_set_parent, 74 }; 75 76 static struct clk *clk_sp810_timerclken_of_get(struct of_phandle_args *clkspec, 77 void *data) 78 { 79 struct clk_sp810 *sp810 = data; 80 81 if (WARN_ON(clkspec->args_count != 1 || 82 clkspec->args[0] >= ARRAY_SIZE(sp810->timerclken))) 83 return NULL; 84 85 return sp810->timerclken[clkspec->args[0]].clk; 86 } 87 88 static void __init clk_sp810_of_setup(struct device_node *node) 89 { 90 struct clk_sp810 *sp810 = kzalloc(sizeof(*sp810), GFP_KERNEL); 91 const char *parent_names[2]; 92 int num = ARRAY_SIZE(parent_names); 93 char name[12]; 94 struct clk_init_data init; 95 static int instance; 96 int i; 97 bool deprecated; 98 99 if (!sp810) 100 return; 101 102 if (of_clk_parent_fill(node, parent_names, num) != num) { 103 pr_warn("Failed to obtain parent clocks for SP810!\n"); 104 kfree(sp810); 105 return; 106 } 107 108 sp810->node = node; 109 sp810->base = of_iomap(node, 0); 110 spin_lock_init(&sp810->lock); 111 112 init.name = name; 113 init.ops = &clk_sp810_timerclken_ops; 114 init.flags = CLK_IS_BASIC; 115 init.parent_names = parent_names; 116 init.num_parents = num; 117 118 deprecated = !of_find_property(node, "assigned-clock-parents", NULL); 119 120 for (i = 0; i < ARRAY_SIZE(sp810->timerclken); i++) { 121 snprintf(name, sizeof(name), "sp810_%d_%d", instance, i); 122 123 sp810->timerclken[i].sp810 = sp810; 124 sp810->timerclken[i].channel = i; 125 sp810->timerclken[i].hw.init = &init; 126 127 /* 128 * If DT isn't setting the parent, force it to be 129 * the 1 MHz clock without going through the framework. 130 * We do this before clk_register() so that it can determine 131 * the parent and setup the tree properly. 132 */ 133 if (deprecated) 134 init.ops->set_parent(&sp810->timerclken[i].hw, 1); 135 136 sp810->timerclken[i].clk = clk_register(NULL, 137 &sp810->timerclken[i].hw); 138 WARN_ON(IS_ERR(sp810->timerclken[i].clk)); 139 } 140 141 of_clk_add_provider(node, clk_sp810_timerclken_of_get, sp810); 142 instance++; 143 } 144 CLK_OF_DECLARE(sp810, "arm,sp810", clk_sp810_of_setup); 145