1 /* 2 * linux/include/linux/clk-provider.h 3 * 4 * Copyright (c) 2010-2011 Jeremy Kerr <jeremy.kerr@canonical.com> 5 * Copyright (C) 2011-2012 Linaro Ltd <mturquette@linaro.org> 6 * 7 * This program is free software; you can redistribute it and/or modify 8 * it under the terms of the GNU General Public License version 2 as 9 * published by the Free Software Foundation. 10 */ 11 #ifndef __LINUX_CLK_PROVIDER_H 12 #define __LINUX_CLK_PROVIDER_H 13 14 #include <linux/clk.h> 15 16 #ifdef CONFIG_COMMON_CLK 17 18 /** 19 * struct clk_hw - handle for traversing from a struct clk to its corresponding 20 * hardware-specific structure. struct clk_hw should be declared within struct 21 * clk_foo and then referenced by the struct clk instance that uses struct 22 * clk_foo's clk_ops 23 * 24 * clk: pointer to the struct clk instance that points back to this struct 25 * clk_hw instance 26 */ 27 struct clk_hw { 28 struct clk *clk; 29 }; 30 31 /* 32 * flags used across common struct clk. these flags should only affect the 33 * top-level framework. custom flags for dealing with hardware specifics 34 * belong in struct clk_foo 35 */ 36 #define CLK_SET_RATE_GATE BIT(0) /* must be gated across rate change */ 37 #define CLK_SET_PARENT_GATE BIT(1) /* must be gated across re-parent */ 38 #define CLK_SET_RATE_PARENT BIT(2) /* propagate rate change up one level */ 39 #define CLK_IGNORE_UNUSED BIT(3) /* do not gate even if unused */ 40 #define CLK_IS_ROOT BIT(4) /* root clk, has no parent */ 41 42 /** 43 * struct clk_ops - Callback operations for hardware clocks; these are to 44 * be provided by the clock implementation, and will be called by drivers 45 * through the clk_* api. 46 * 47 * @prepare: Prepare the clock for enabling. This must not return until 48 * the clock is fully prepared, and it's safe to call clk_enable. 49 * This callback is intended to allow clock implementations to 50 * do any initialisation that may sleep. Called with 51 * prepare_lock held. 52 * 53 * @unprepare: Release the clock from its prepared state. This will typically 54 * undo any work done in the @prepare callback. Called with 55 * prepare_lock held. 56 * 57 * @enable: Enable the clock atomically. This must not return until the 58 * clock is generating a valid clock signal, usable by consumer 59 * devices. Called with enable_lock held. This function must not 60 * sleep. 61 * 62 * @disable: Disable the clock atomically. Called with enable_lock held. 63 * This function must not sleep. 64 * 65 * @recalc_rate Recalculate the rate of this clock, by quering hardware. The 66 * parent rate is an input parameter. It is up to the caller to 67 * insure that the prepare_mutex is held across this call. 68 * Returns the calculated rate. Optional, but recommended - if 69 * this op is not set then clock rate will be initialized to 0. 70 * 71 * @round_rate: Given a target rate as input, returns the closest rate actually 72 * supported by the clock. 73 * 74 * @get_parent: Queries the hardware to determine the parent of a clock. The 75 * return value is a u8 which specifies the index corresponding to 76 * the parent clock. This index can be applied to either the 77 * .parent_names or .parents arrays. In short, this function 78 * translates the parent value read from hardware into an array 79 * index. Currently only called when the clock is initialized by 80 * __clk_init. This callback is mandatory for clocks with 81 * multiple parents. It is optional (and unnecessary) for clocks 82 * with 0 or 1 parents. 83 * 84 * @set_parent: Change the input source of this clock; for clocks with multiple 85 * possible parents specify a new parent by passing in the index 86 * as a u8 corresponding to the parent in either the .parent_names 87 * or .parents arrays. This function in affect translates an 88 * array index into the value programmed into the hardware. 89 * Returns 0 on success, -EERROR otherwise. 90 * 91 * @set_rate: Change the rate of this clock. If this callback returns 92 * CLK_SET_RATE_PARENT, the rate change will be propagated to the 93 * parent clock (which may propagate again if the parent clock 94 * also sets this flag). The requested rate of the parent is 95 * passed back from the callback in the second 'unsigned long *' 96 * argument. Note that it is up to the hardware clock's set_rate 97 * implementation to insure that clocks do not run out of spec 98 * when propgating the call to set_rate up to the parent. One way 99 * to do this is to gate the clock (via clk_disable and/or 100 * clk_unprepare) before calling clk_set_rate, then ungating it 101 * afterward. If your clock also has the CLK_GATE_SET_RATE flag 102 * set then this will insure safety. Returns 0 on success, 103 * -EERROR otherwise. 104 * 105 * The clk_enable/clk_disable and clk_prepare/clk_unprepare pairs allow 106 * implementations to split any work between atomic (enable) and sleepable 107 * (prepare) contexts. If enabling a clock requires code that might sleep, 108 * this must be done in clk_prepare. Clock enable code that will never be 109 * called in a sleepable context may be implement in clk_enable. 110 * 111 * Typically, drivers will call clk_prepare when a clock may be needed later 112 * (eg. when a device is opened), and clk_enable when the clock is actually 113 * required (eg. from an interrupt). Note that clk_prepare MUST have been 114 * called before clk_enable. 115 */ 116 struct clk_ops { 117 int (*prepare)(struct clk_hw *hw); 118 void (*unprepare)(struct clk_hw *hw); 119 int (*enable)(struct clk_hw *hw); 120 void (*disable)(struct clk_hw *hw); 121 int (*is_enabled)(struct clk_hw *hw); 122 unsigned long (*recalc_rate)(struct clk_hw *hw, 123 unsigned long parent_rate); 124 long (*round_rate)(struct clk_hw *hw, unsigned long, 125 unsigned long *); 126 int (*set_parent)(struct clk_hw *hw, u8 index); 127 u8 (*get_parent)(struct clk_hw *hw); 128 int (*set_rate)(struct clk_hw *hw, unsigned long); 129 void (*init)(struct clk_hw *hw); 130 }; 131 132 /* 133 * DOC: Basic clock implementations common to many platforms 134 * 135 * Each basic clock hardware type is comprised of a structure describing the 136 * clock hardware, implementations of the relevant callbacks in struct clk_ops, 137 * unique flags for that hardware type, a registration function and an 138 * alternative macro for static initialization 139 */ 140 141 /** 142 * struct clk_fixed_rate - fixed-rate clock 143 * @hw: handle between common and hardware-specific interfaces 144 * @fixed_rate: constant frequency of clock 145 */ 146 struct clk_fixed_rate { 147 struct clk_hw hw; 148 unsigned long fixed_rate; 149 u8 flags; 150 }; 151 152 struct clk *clk_register_fixed_rate(struct device *dev, const char *name, 153 const char *parent_name, unsigned long flags, 154 unsigned long fixed_rate); 155 156 /** 157 * struct clk_gate - gating clock 158 * 159 * @hw: handle between common and hardware-specific interfaces 160 * @reg: register controlling gate 161 * @bit_idx: single bit controlling gate 162 * @flags: hardware-specific flags 163 * @lock: register lock 164 * 165 * Clock which can gate its output. Implements .enable & .disable 166 * 167 * Flags: 168 * CLK_GATE_SET_DISABLE - by default this clock sets the bit at bit_idx to 169 * enable the clock. Setting this flag does the opposite: setting the bit 170 * disable the clock and clearing it enables the clock 171 */ 172 struct clk_gate { 173 struct clk_hw hw; 174 void __iomem *reg; 175 u8 bit_idx; 176 u8 flags; 177 spinlock_t *lock; 178 char *parent[1]; 179 }; 180 181 #define CLK_GATE_SET_TO_DISABLE BIT(0) 182 183 struct clk *clk_register_gate(struct device *dev, const char *name, 184 const char *parent_name, unsigned long flags, 185 void __iomem *reg, u8 bit_idx, 186 u8 clk_gate_flags, spinlock_t *lock); 187 188 /** 189 * struct clk_divider - adjustable divider clock 190 * 191 * @hw: handle between common and hardware-specific interfaces 192 * @reg: register containing the divider 193 * @shift: shift to the divider bit field 194 * @width: width of the divider bit field 195 * @lock: register lock 196 * 197 * Clock with an adjustable divider affecting its output frequency. Implements 198 * .recalc_rate, .set_rate and .round_rate 199 * 200 * Flags: 201 * CLK_DIVIDER_ONE_BASED - by default the divisor is the value read from the 202 * register plus one. If CLK_DIVIDER_ONE_BASED is set then the divider is 203 * the raw value read from the register, with the value of zero considered 204 * invalid 205 * CLK_DIVIDER_POWER_OF_TWO - clock divisor is 2 raised to the value read from 206 * the hardware register 207 */ 208 struct clk_divider { 209 struct clk_hw hw; 210 void __iomem *reg; 211 u8 shift; 212 u8 width; 213 u8 flags; 214 spinlock_t *lock; 215 char *parent[1]; 216 }; 217 218 #define CLK_DIVIDER_ONE_BASED BIT(0) 219 #define CLK_DIVIDER_POWER_OF_TWO BIT(1) 220 221 struct clk *clk_register_divider(struct device *dev, const char *name, 222 const char *parent_name, unsigned long flags, 223 void __iomem *reg, u8 shift, u8 width, 224 u8 clk_divider_flags, spinlock_t *lock); 225 226 /** 227 * struct clk_mux - multiplexer clock 228 * 229 * @hw: handle between common and hardware-specific interfaces 230 * @reg: register controlling multiplexer 231 * @shift: shift to multiplexer bit field 232 * @width: width of mutliplexer bit field 233 * @num_clks: number of parent clocks 234 * @lock: register lock 235 * 236 * Clock with multiple selectable parents. Implements .get_parent, .set_parent 237 * and .recalc_rate 238 * 239 * Flags: 240 * CLK_MUX_INDEX_ONE - register index starts at 1, not 0 241 * CLK_MUX_INDEX_BITWISE - register index is a single bit (power of two) 242 */ 243 struct clk_mux { 244 struct clk_hw hw; 245 void __iomem *reg; 246 u8 shift; 247 u8 width; 248 u8 flags; 249 spinlock_t *lock; 250 }; 251 252 #define CLK_MUX_INDEX_ONE BIT(0) 253 #define CLK_MUX_INDEX_BIT BIT(1) 254 255 struct clk *clk_register_mux(struct device *dev, const char *name, 256 char **parent_names, u8 num_parents, unsigned long flags, 257 void __iomem *reg, u8 shift, u8 width, 258 u8 clk_mux_flags, spinlock_t *lock); 259 260 /** 261 * clk_register - allocate a new clock, register it and return an opaque cookie 262 * @dev: device that is registering this clock 263 * @name: clock name 264 * @ops: operations this clock supports 265 * @hw: link to hardware-specific clock data 266 * @parent_names: array of string names for all possible parents 267 * @num_parents: number of possible parents 268 * @flags: framework-level hints and quirks 269 * 270 * clk_register is the primary interface for populating the clock tree with new 271 * clock nodes. It returns a pointer to the newly allocated struct clk which 272 * cannot be dereferenced by driver code but may be used in conjuction with the 273 * rest of the clock API. 274 */ 275 struct clk *clk_register(struct device *dev, const char *name, 276 const struct clk_ops *ops, struct clk_hw *hw, 277 char **parent_names, u8 num_parents, unsigned long flags); 278 279 /* helper functions */ 280 const char *__clk_get_name(struct clk *clk); 281 struct clk_hw *__clk_get_hw(struct clk *clk); 282 u8 __clk_get_num_parents(struct clk *clk); 283 struct clk *__clk_get_parent(struct clk *clk); 284 inline int __clk_get_enable_count(struct clk *clk); 285 inline int __clk_get_prepare_count(struct clk *clk); 286 unsigned long __clk_get_rate(struct clk *clk); 287 unsigned long __clk_get_flags(struct clk *clk); 288 int __clk_is_enabled(struct clk *clk); 289 struct clk *__clk_lookup(const char *name); 290 291 /* 292 * FIXME clock api without lock protection 293 */ 294 int __clk_prepare(struct clk *clk); 295 void __clk_unprepare(struct clk *clk); 296 void __clk_reparent(struct clk *clk, struct clk *new_parent); 297 unsigned long __clk_round_rate(struct clk *clk, unsigned long rate); 298 299 #endif /* CONFIG_COMMON_CLK */ 300 #endif /* CLK_PROVIDER_H */ 301