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 #include "clock.h" 26 27 struct clk_ti_autoidle { 28 struct clk_omap_reg reg; 29 u8 shift; 30 u8 flags; 31 const char *name; 32 struct list_head node; 33 }; 34 35 #define AUTOIDLE_LOW 0x1 36 37 static LIST_HEAD(autoidle_clks); 38 static LIST_HEAD(clk_hw_omap_clocks); 39 40 /** 41 * omap2_clk_deny_idle - disable autoidle on an OMAP clock 42 * @clk: struct clk * to disable autoidle for 43 * 44 * Disable autoidle on an OMAP clock. 45 */ 46 int omap2_clk_deny_idle(struct clk *clk) 47 { 48 struct clk_hw_omap *c; 49 50 c = to_clk_hw_omap(__clk_get_hw(clk)); 51 if (c->ops && c->ops->deny_idle) 52 c->ops->deny_idle(c); 53 return 0; 54 } 55 56 /** 57 * omap2_clk_allow_idle - enable autoidle on an OMAP clock 58 * @clk: struct clk * to enable autoidle for 59 * 60 * Enable autoidle on an OMAP clock. 61 */ 62 int omap2_clk_allow_idle(struct clk *clk) 63 { 64 struct clk_hw_omap *c; 65 66 c = to_clk_hw_omap(__clk_get_hw(clk)); 67 if (c->ops && c->ops->allow_idle) 68 c->ops->allow_idle(c); 69 return 0; 70 } 71 72 static void _allow_autoidle(struct clk_ti_autoidle *clk) 73 { 74 u32 val; 75 76 val = ti_clk_ll_ops->clk_readl(&clk->reg); 77 78 if (clk->flags & AUTOIDLE_LOW) 79 val &= ~(1 << clk->shift); 80 else 81 val |= (1 << clk->shift); 82 83 ti_clk_ll_ops->clk_writel(val, &clk->reg); 84 } 85 86 static void _deny_autoidle(struct clk_ti_autoidle *clk) 87 { 88 u32 val; 89 90 val = ti_clk_ll_ops->clk_readl(&clk->reg); 91 92 if (clk->flags & AUTOIDLE_LOW) 93 val |= (1 << clk->shift); 94 else 95 val &= ~(1 << clk->shift); 96 97 ti_clk_ll_ops->clk_writel(val, &clk->reg); 98 } 99 100 /** 101 * _clk_generic_allow_autoidle_all - enable autoidle for all clocks 102 * 103 * Enables hardware autoidle for all registered DT clocks, which have 104 * the feature. 105 */ 106 static void _clk_generic_allow_autoidle_all(void) 107 { 108 struct clk_ti_autoidle *c; 109 110 list_for_each_entry(c, &autoidle_clks, node) 111 _allow_autoidle(c); 112 } 113 114 /** 115 * _clk_generic_deny_autoidle_all - disable autoidle for all clocks 116 * 117 * Disables hardware autoidle for all registered DT clocks, which have 118 * the feature. 119 */ 120 static void _clk_generic_deny_autoidle_all(void) 121 { 122 struct clk_ti_autoidle *c; 123 124 list_for_each_entry(c, &autoidle_clks, node) 125 _deny_autoidle(c); 126 } 127 128 /** 129 * of_ti_clk_autoidle_setup - sets up hardware autoidle for a clock 130 * @node: pointer to the clock device node 131 * 132 * Checks if a clock has hardware autoidle support or not (check 133 * for presence of 'ti,autoidle-shift' property in the device tree 134 * node) and sets up the hardware autoidle feature for the clock 135 * if available. If autoidle is available, the clock is also added 136 * to the autoidle list for later processing. Returns 0 on success, 137 * negative error value on failure. 138 */ 139 int __init of_ti_clk_autoidle_setup(struct device_node *node) 140 { 141 u32 shift; 142 struct clk_ti_autoidle *clk; 143 int ret; 144 145 /* Check if this clock has autoidle support or not */ 146 if (of_property_read_u32(node, "ti,autoidle-shift", &shift)) 147 return 0; 148 149 clk = kzalloc(sizeof(*clk), GFP_KERNEL); 150 151 if (!clk) 152 return -ENOMEM; 153 154 clk->shift = shift; 155 clk->name = node->name; 156 ret = ti_clk_get_reg_addr(node, 0, &clk->reg); 157 if (ret) { 158 kfree(clk); 159 return ret; 160 } 161 162 if (of_property_read_bool(node, "ti,invert-autoidle-bit")) 163 clk->flags |= AUTOIDLE_LOW; 164 165 list_add(&clk->node, &autoidle_clks); 166 167 return 0; 168 } 169 170 /** 171 * omap2_init_clk_hw_omap_clocks - initialize an OMAP clock 172 * @hw: struct clk_hw * to initialize 173 * 174 * Add an OMAP clock @clk to the internal list of OMAP clocks. Used 175 * temporarily for autoidle handling, until this support can be 176 * integrated into the common clock framework code in some way. No 177 * return value. 178 */ 179 void omap2_init_clk_hw_omap_clocks(struct clk_hw *hw) 180 { 181 struct clk_hw_omap *c; 182 183 if (clk_hw_get_flags(hw) & CLK_IS_BASIC) 184 return; 185 186 c = to_clk_hw_omap(hw); 187 list_add(&c->node, &clk_hw_omap_clocks); 188 } 189 190 /** 191 * omap2_clk_enable_autoidle_all - enable autoidle on all OMAP clocks that 192 * support it 193 * 194 * Enable clock autoidle on all OMAP clocks that have allow_idle 195 * function pointers associated with them. This function is intended 196 * to be temporary until support for this is added to the common clock 197 * code. Returns 0. 198 */ 199 int omap2_clk_enable_autoidle_all(void) 200 { 201 struct clk_hw_omap *c; 202 203 list_for_each_entry(c, &clk_hw_omap_clocks, node) 204 if (c->ops && c->ops->allow_idle) 205 c->ops->allow_idle(c); 206 207 _clk_generic_allow_autoidle_all(); 208 209 return 0; 210 } 211 212 /** 213 * omap2_clk_disable_autoidle_all - disable autoidle on all OMAP clocks that 214 * support it 215 * 216 * Disable clock autoidle on all OMAP clocks that have allow_idle 217 * function pointers associated with them. This function is intended 218 * to be temporary until support for this is added to the common clock 219 * code. Returns 0. 220 */ 221 int omap2_clk_disable_autoidle_all(void) 222 { 223 struct clk_hw_omap *c; 224 225 list_for_each_entry(c, &clk_hw_omap_clocks, node) 226 if (c->ops && c->ops->deny_idle) 227 c->ops->deny_idle(c); 228 229 _clk_generic_deny_autoidle_all(); 230 231 return 0; 232 } 233