1 /* 2 * TI clock autoidle support 3 * 4 * Copyright (C) 2013 Texas Instruments, Inc. 5 * 6 * Tero Kristo <t-kristo@ti.com> 7 * 8 * This program is free software; you can redistribute it and/or modify 9 * it under the terms of the GNU General Public License version 2 as 10 * published by the Free Software Foundation. 11 * 12 * This program is distributed "as is" WITHOUT ANY WARRANTY of any 13 * kind, whether express or implied; without even the implied warranty 14 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15 * GNU General Public License for more details. 16 */ 17 18 #include <linux/clk-provider.h> 19 #include <linux/slab.h> 20 #include <linux/io.h> 21 #include <linux/of.h> 22 #include <linux/of_address.h> 23 #include <linux/clk/ti.h> 24 25 struct clk_ti_autoidle { 26 void __iomem *reg; 27 u8 shift; 28 u8 flags; 29 const char *name; 30 struct list_head node; 31 }; 32 33 #define AUTOIDLE_LOW 0x1 34 35 static LIST_HEAD(autoidle_clks); 36 37 static void ti_allow_autoidle(struct clk_ti_autoidle *clk) 38 { 39 u32 val; 40 41 val = ti_clk_ll_ops->clk_readl(clk->reg); 42 43 if (clk->flags & AUTOIDLE_LOW) 44 val &= ~(1 << clk->shift); 45 else 46 val |= (1 << clk->shift); 47 48 ti_clk_ll_ops->clk_writel(val, clk->reg); 49 } 50 51 static void ti_deny_autoidle(struct clk_ti_autoidle *clk) 52 { 53 u32 val; 54 55 val = ti_clk_ll_ops->clk_readl(clk->reg); 56 57 if (clk->flags & AUTOIDLE_LOW) 58 val |= (1 << clk->shift); 59 else 60 val &= ~(1 << clk->shift); 61 62 ti_clk_ll_ops->clk_writel(val, clk->reg); 63 } 64 65 /** 66 * of_ti_clk_allow_autoidle_all - enable autoidle for all clocks 67 * 68 * Enables hardware autoidle for all registered DT clocks, which have 69 * the feature. 70 */ 71 void of_ti_clk_allow_autoidle_all(void) 72 { 73 struct clk_ti_autoidle *c; 74 75 list_for_each_entry(c, &autoidle_clks, node) 76 ti_allow_autoidle(c); 77 } 78 79 /** 80 * of_ti_clk_deny_autoidle_all - disable autoidle for all clocks 81 * 82 * Disables hardware autoidle for all registered DT clocks, which have 83 * the feature. 84 */ 85 void of_ti_clk_deny_autoidle_all(void) 86 { 87 struct clk_ti_autoidle *c; 88 89 list_for_each_entry(c, &autoidle_clks, node) 90 ti_deny_autoidle(c); 91 } 92 93 /** 94 * of_ti_clk_autoidle_setup - sets up hardware autoidle for a clock 95 * @node: pointer to the clock device node 96 * 97 * Checks if a clock has hardware autoidle support or not (check 98 * for presence of 'ti,autoidle-shift' property in the device tree 99 * node) and sets up the hardware autoidle feature for the clock 100 * if available. If autoidle is available, the clock is also added 101 * to the autoidle list for later processing. Returns 0 on success, 102 * negative error value on failure. 103 */ 104 int __init of_ti_clk_autoidle_setup(struct device_node *node) 105 { 106 u32 shift; 107 struct clk_ti_autoidle *clk; 108 109 /* Check if this clock has autoidle support or not */ 110 if (of_property_read_u32(node, "ti,autoidle-shift", &shift)) 111 return 0; 112 113 clk = kzalloc(sizeof(*clk), GFP_KERNEL); 114 115 if (!clk) 116 return -ENOMEM; 117 118 clk->shift = shift; 119 clk->name = node->name; 120 clk->reg = ti_clk_get_reg_addr(node, 0); 121 122 if (IS_ERR(clk->reg)) { 123 kfree(clk); 124 return -EINVAL; 125 } 126 127 if (of_property_read_bool(node, "ti,invert-autoidle-bit")) 128 clk->flags |= AUTOIDLE_LOW; 129 130 list_add(&clk->node, &autoidle_clks); 131 132 return 0; 133 } 134