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 39 /* 40 * we have some non-atomic read/write 41 * operations behind it, so lets 42 * take one lock for handling autoidle 43 * of all clocks 44 */ 45 static DEFINE_SPINLOCK(autoidle_spinlock); 46 47 static int _omap2_clk_deny_idle(struct clk_hw_omap *clk) 48 { 49 if (clk->ops && clk->ops->deny_idle) { 50 unsigned long irqflags; 51 52 spin_lock_irqsave(&autoidle_spinlock, irqflags); 53 clk->autoidle_count++; 54 if (clk->autoidle_count == 1) 55 clk->ops->deny_idle(clk); 56 57 spin_unlock_irqrestore(&autoidle_spinlock, irqflags); 58 } 59 return 0; 60 } 61 62 static int _omap2_clk_allow_idle(struct clk_hw_omap *clk) 63 { 64 if (clk->ops && clk->ops->allow_idle) { 65 unsigned long irqflags; 66 67 spin_lock_irqsave(&autoidle_spinlock, irqflags); 68 clk->autoidle_count--; 69 if (clk->autoidle_count == 0) 70 clk->ops->allow_idle(clk); 71 72 spin_unlock_irqrestore(&autoidle_spinlock, irqflags); 73 } 74 return 0; 75 } 76 77 /** 78 * omap2_clk_deny_idle - disable autoidle on an OMAP clock 79 * @clk: struct clk * to disable autoidle for 80 * 81 * Disable autoidle on an OMAP clock. 82 */ 83 int omap2_clk_deny_idle(struct clk *clk) 84 { 85 struct clk_hw *hw; 86 87 if (!clk) 88 return -EINVAL; 89 90 hw = __clk_get_hw(clk); 91 92 if (omap2_clk_is_hw_omap(hw)) { 93 struct clk_hw_omap *c = to_clk_hw_omap(hw); 94 95 return _omap2_clk_deny_idle(c); 96 } 97 98 return -EINVAL; 99 } 100 101 /** 102 * omap2_clk_allow_idle - enable autoidle on an OMAP clock 103 * @clk: struct clk * to enable autoidle for 104 * 105 * Enable autoidle on an OMAP clock. 106 */ 107 int omap2_clk_allow_idle(struct clk *clk) 108 { 109 struct clk_hw *hw; 110 111 if (!clk) 112 return -EINVAL; 113 114 hw = __clk_get_hw(clk); 115 116 if (omap2_clk_is_hw_omap(hw)) { 117 struct clk_hw_omap *c = to_clk_hw_omap(hw); 118 119 return _omap2_clk_allow_idle(c); 120 } 121 122 return -EINVAL; 123 } 124 125 static void _allow_autoidle(struct clk_ti_autoidle *clk) 126 { 127 u32 val; 128 129 val = ti_clk_ll_ops->clk_readl(&clk->reg); 130 131 if (clk->flags & AUTOIDLE_LOW) 132 val &= ~(1 << clk->shift); 133 else 134 val |= (1 << clk->shift); 135 136 ti_clk_ll_ops->clk_writel(val, &clk->reg); 137 } 138 139 static void _deny_autoidle(struct clk_ti_autoidle *clk) 140 { 141 u32 val; 142 143 val = ti_clk_ll_ops->clk_readl(&clk->reg); 144 145 if (clk->flags & AUTOIDLE_LOW) 146 val |= (1 << clk->shift); 147 else 148 val &= ~(1 << clk->shift); 149 150 ti_clk_ll_ops->clk_writel(val, &clk->reg); 151 } 152 153 /** 154 * _clk_generic_allow_autoidle_all - enable autoidle for all clocks 155 * 156 * Enables hardware autoidle for all registered DT clocks, which have 157 * the feature. 158 */ 159 static void _clk_generic_allow_autoidle_all(void) 160 { 161 struct clk_ti_autoidle *c; 162 163 list_for_each_entry(c, &autoidle_clks, node) 164 _allow_autoidle(c); 165 } 166 167 /** 168 * _clk_generic_deny_autoidle_all - disable autoidle for all clocks 169 * 170 * Disables hardware autoidle for all registered DT clocks, which have 171 * the feature. 172 */ 173 static void _clk_generic_deny_autoidle_all(void) 174 { 175 struct clk_ti_autoidle *c; 176 177 list_for_each_entry(c, &autoidle_clks, node) 178 _deny_autoidle(c); 179 } 180 181 /** 182 * of_ti_clk_autoidle_setup - sets up hardware autoidle for a clock 183 * @node: pointer to the clock device node 184 * 185 * Checks if a clock has hardware autoidle support or not (check 186 * for presence of 'ti,autoidle-shift' property in the device tree 187 * node) and sets up the hardware autoidle feature for the clock 188 * if available. If autoidle is available, the clock is also added 189 * to the autoidle list for later processing. Returns 0 on success, 190 * negative error value on failure. 191 */ 192 int __init of_ti_clk_autoidle_setup(struct device_node *node) 193 { 194 u32 shift; 195 struct clk_ti_autoidle *clk; 196 int ret; 197 198 /* Check if this clock has autoidle support or not */ 199 if (of_property_read_u32(node, "ti,autoidle-shift", &shift)) 200 return 0; 201 202 clk = kzalloc(sizeof(*clk), GFP_KERNEL); 203 204 if (!clk) 205 return -ENOMEM; 206 207 clk->shift = shift; 208 clk->name = ti_dt_clk_name(node); 209 ret = ti_clk_get_reg_addr(node, 0, &clk->reg); 210 if (ret) { 211 kfree(clk); 212 return ret; 213 } 214 215 if (of_property_read_bool(node, "ti,invert-autoidle-bit")) 216 clk->flags |= AUTOIDLE_LOW; 217 218 list_add(&clk->node, &autoidle_clks); 219 220 return 0; 221 } 222 223 /** 224 * omap2_clk_enable_autoidle_all - enable autoidle on all OMAP clocks that 225 * support it 226 * 227 * Enable clock autoidle on all OMAP clocks that have allow_idle 228 * function pointers associated with them. This function is intended 229 * to be temporary until support for this is added to the common clock 230 * code. Returns 0. 231 */ 232 int omap2_clk_enable_autoidle_all(void) 233 { 234 int ret; 235 236 ret = omap2_clk_for_each(_omap2_clk_allow_idle); 237 if (ret) 238 return ret; 239 240 _clk_generic_allow_autoidle_all(); 241 242 return 0; 243 } 244 245 /** 246 * omap2_clk_disable_autoidle_all - disable autoidle on all OMAP clocks that 247 * support it 248 * 249 * Disable clock autoidle on all OMAP clocks that have allow_idle 250 * function pointers associated with them. This function is intended 251 * to be temporary until support for this is added to the common clock 252 * code. Returns 0. 253 */ 254 int omap2_clk_disable_autoidle_all(void) 255 { 256 int ret; 257 258 ret = omap2_clk_for_each(_omap2_clk_deny_idle); 259 if (ret) 260 return ret; 261 262 _clk_generic_deny_autoidle_all(); 263 264 return 0; 265 } 266