include/clk.h

   1 /* SPDX-License-Identifier: GPL-2.0+ */
   2 /*
   3  * Copyright (c) 2015 Google, Inc
   4  * Written by Simon Glass <sjg@chromium.org>
   5  * Copyright (c) 2016, NVIDIA CORPORATION.
   6  */
   7
   8 #ifndef _CLK_H_
   9 #define _CLK_H_
  10
  11 #include <linux/errno.h>
  12 #include <linux/types.h>
  13
  14 /**
  15  * A clock is a hardware signal that oscillates autonomously at a specific
  16  * frequency and duty cycle. Most hardware modules require one or more clock
  17  * signal to drive their operation. Clock signals are typically generated
  18  * externally to the HW module consuming them, by an entity this API calls a
  19  * clock provider. This API provides a standard means for drivers to enable and
  20  * disable clocks, and to set the rate at which they oscillate.
  21  *
  22  * A driver that implements UCLASS_CLOCK is a clock provider. A provider will
  23  * often implement multiple separate clocks, since the hardware it manages
  24  * often has this capability. clock_uclass.h describes the interface which
  25  * clock providers must implement.
  26  *
  27  * Clock consumers/clients are the HW modules driven by the clock signals. This
  28  * header file describes the API used by drivers for those HW modules.
  29  */
  30
  31 struct udevice;
  32
  33 /**
  34  * struct clk - A handle to (allowing control of) a single clock.
  35  *
  36  * Clients provide storage for clock handles. The content of the structure is
  37  * managed solely by the clock API and clock drivers. A clock struct is
  38  * initialized by "get"ing the clock struct. The clock struct is passed to all
  39  * other clock APIs to identify which clock signal to operate upon.
  40  *
  41  * @dev: The device which implements the clock signal.
  42  * @id: The clock signal ID within the provider.
  43  *
  44  * Currently, the clock API assumes that a single integer ID is enough to
  45  * identify and configure any clock signal for any clock provider. If this
  46  * assumption becomes invalid in the future, the struct could be expanded to
  47  * either (a) add more fields to allow clock providers to store additional
  48  * information, or (b) replace the id field with an opaque pointer, which the
  49  * provider would dynamically allocated during its .of_xlate op, and process
  50  * during is .request op. This may require the addition of an extra op to clean
  51  * up the allocation.
  52  */
  53 struct clk {
  54         struct udevice *dev;
  55         /*
  56          * Written by of_xlate. We assume a single id is enough for now. In the
  57          * future, we might add more fields here.
  58          */
  59         unsigned long id;
  60 };
  61
  62 /**
  63  * struct clk_bulk - A handle to (allowing control of) a bulk of clocks.
  64  *
  65  * Clients provide storage for the clock bulk. The content of the structure is
  66  * managed solely by the clock API. A clock bulk struct is
  67  * initialized by "get"ing the clock bulk struct.
  68  * The clock bulk struct is passed to all other bulk clock APIs to apply
  69  * the API to all the clock in the bulk struct.
  70  *
  71  * @clks: An array of clock handles.
  72  * @count: The number of clock handles in the clks array.
  73  */
  74 struct clk_bulk {
  75         struct clk *clks;
  76         unsigned int count;
  77 };
  78
  79 #if CONFIG_IS_ENABLED(OF_CONTROL) && CONFIG_IS_ENABLED(CLK)
  80 struct phandle_1_arg;
  81 int clk_get_by_index_platdata(struct udevice *dev, int index,
  82                               struct phandle_1_arg *cells, struct clk *clk);
  83
  84 /**
  85  * clock_get_by_index - Get/request a clock by integer index.
  86  *
  87  * This looks up and requests a clock. The index is relative to the client
  88  * device; each device is assumed to have n clocks associated with it somehow,
  89  * and this function finds and requests one of them. The mapping of client
  90  * device clock indices to provider clocks may be via device-tree properties,
  91  * board-provided mapping tables, or some other mechanism.
  92  *
  93  * @dev:        The client device.
  94  * @index:      The index of the clock to request, within the client's list of
  95  *              clocks.
  96  * @clock       A pointer to a clock struct to initialize.
  97  * @return 0 if OK, or a negative error code.
  98  */
  99 int clk_get_by_index(struct udevice *dev, int index, struct clk *clk);
 100
 101 /**
 102  * clock_get_bulk - Get/request all clocks of a device.
 103  *
 104  * This looks up and requests all clocks of the client device; each device is
 105  * assumed to have n clocks associated with it somehow, and this function finds
 106  * and requests all of them in a separate structure. The mapping of client
 107  * device clock indices to provider clocks may be via device-tree properties,
 108  * board-provided mapping tables, or some other mechanism.
 109  *
 110  * @dev:        The client device.
 111  * @bulk        A pointer to a clock bulk struct to initialize.
 112  * @return 0 if OK, or a negative error code.
 113  */
 114 int clk_get_bulk(struct udevice *dev, struct clk_bulk *bulk);
 115
 116 /**
 117  * clock_get_by_name - Get/request a clock by name.
 118  *
 119  * This looks up and requests a clock. The name is relative to the client
 120  * device; each device is assumed to have n clocks associated with it somehow,
 121  * and this function finds and requests one of them. The mapping of client
 122  * device clock names to provider clocks may be via device-tree properties,
 123  * board-provided mapping tables, or some other mechanism.
 124  *
 125  * @dev:        The client device.
 126  * @name:       The name of the clock to request, within the client's list of
 127  *              clocks.
 128  * @clock:      A pointer to a clock struct to initialize.
 129  * @return 0 if OK, or a negative error code.
 130  */
 131 int clk_get_by_name(struct udevice *dev, const char *name, struct clk *clk);
 132
 133 /**
 134  * clk_release_all() - Disable (turn off)/Free an array of previously
 135  * requested clocks.
 136  *
 137  * For each clock contained in the clock array, this function will check if
 138  * clock has been previously requested and then will disable and free it.
 139  *
 140  * @clk:        A clock struct array that was previously successfully
 141  *              requested by clk_request/get_by_*().
 142  * @count       Number of clock contained in the array
 143  * @return zero on success, or -ve error code.
 144  */
 145 int clk_release_all(struct clk *clk, int count);
 146
 147 #else
 148 static inline int clk_get_by_index(struct udevice *dev, int index,
 149                                    struct clk *clk)
 150 {
 151         return -ENOSYS;
 152 }
 153
 154 static inline int clk_get_bulk(struct udevice *dev, struct clk_bulk *bulk)
 155 {
 156         return -ENOSYS;
 157 }
 158
 159 static inline int clk_get_by_name(struct udevice *dev, const char *name,
 160                            struct clk *clk)
 161 {
 162         return -ENOSYS;
 163 }
 164
 165 static inline int clk_release_all(struct clk *clk, int count)
 166 {
 167         return -ENOSYS;
 168 }
 169 #endif
 170
 171 #if (CONFIG_IS_ENABLED(OF_CONTROL) && !CONFIG_IS_ENABLED(OF_PLATDATA)) && \
 172         CONFIG_IS_ENABLED(CLK)
 173 /**
 174  * clk_set_defaults - Process 'assigned-{clocks/clock-parents/clock-rates}'
 175  *                    properties to configure clocks
 176  *
 177  * @dev:        A device to process (the ofnode associated with this device
 178  *              will be processed).
 179  */
 180 int clk_set_defaults(struct udevice *dev);
 181 #else
 182 static inline int clk_set_defaults(struct udevice *dev)
 183 {
 184         return 0;
 185 }
 186 #endif
 187
 188 /**
 189  * clk_release_bulk() - Disable (turn off)/Free an array of previously
 190  * requested clocks in a clock bulk struct.
 191  *
 192  * For each clock contained in the clock bulk struct, this function will check
 193  * if clock has been previously requested and then will disable and free it.
 194  *
 195  * @clk:        A clock bulk struct that was previously successfully
 196  *              requested by clk_get_bulk().
 197  * @return zero on success, or -ve error code.
 198  */
 199 static inline int clk_release_bulk(struct clk_bulk *bulk)
 200 {
 201         return clk_release_all(bulk->clks, bulk->count);
 202 }
 203
 204 /**
 205  * clk_request - Request a clock by provider-specific ID.
 206  *
 207  * This requests a clock using a provider-specific ID. Generally, this function
 208  * should not be used, since clk_get_by_index/name() provide an interface that
 209  * better separates clients from intimate knowledge of clock providers.
 210  * However, this function may be useful in core SoC-specific code.
 211  *
 212  * @dev:        The clock provider device.
 213  * @clock:      A pointer to a clock struct to initialize. The caller must
 214  *              have already initialized any field in this struct which the
 215  *              clock provider uses to identify the clock.
 216  * @return 0 if OK, or a negative error code.
 217  */
 218 int clk_request(struct udevice *dev, struct clk *clk);
 219
 220 /**
 221  * clock_free - Free a previously requested clock.
 222  *
 223  * @clock:      A clock struct that was previously successfully requested by
 224  *              clk_request/get_by_*().
 225  * @return 0 if OK, or a negative error code.
 226  */
 227 int clk_free(struct clk *clk);
 228
 229 /**
 230  * clk_get_rate() - Get current clock rate.
 231  *
 232  * @clk:        A clock struct that was previously successfully requested by
 233  *              clk_request/get_by_*().
 234  * @return clock rate in Hz, or -ve error code.
 235  */
 236 ulong clk_get_rate(struct clk *clk);
 237
 238 /**
 239  * clk_set_rate() - Set current clock rate.
 240  *
 241  * @clk:        A clock struct that was previously successfully requested by
 242  *              clk_request/get_by_*().
 243  * @rate:       New clock rate in Hz.
 244  * @return new rate, or -ve error code.
 245  */
 246 ulong clk_set_rate(struct clk *clk, ulong rate);
 247
 248 /**
 249  * clk_set_parent() - Set current clock parent.
 250  *
 251  * @clk:        A clock struct that was previously successfully requested by
 252  *              clk_request/get_by_*().
 253  * @parent:     A clock struct that was previously successfully requested by
 254  *              clk_request/get_by_*().
 255  * @return new rate, or -ve error code.
 256  */
 257 int clk_set_parent(struct clk *clk, struct clk *parent);
 258
 259 /**
 260  * clk_enable() - Enable (turn on) a clock.
 261  *
 262  * @clk:        A clock struct that was previously successfully requested by
 263  *              clk_request/get_by_*().
 264  * @return zero on success, or -ve error code.
 265  */
 266 int clk_enable(struct clk *clk);
 267
 268 /**
 269  * clk_enable_bulk() - Enable (turn on) all clocks in a clock bulk struct.
 270  *
 271  * @bulk:       A clock bulk struct that was previously successfully requested
 272  *              by clk_get_bulk().
 273  * @return zero on success, or -ve error code.
 274  */
 275 int clk_enable_bulk(struct clk_bulk *bulk);
 276
 277 /**
 278  * clk_disable() - Disable (turn off) a clock.
 279  *
 280  * @clk:        A clock struct that was previously successfully requested by
 281  *              clk_request/get_by_*().
 282  * @return zero on success, or -ve error code.
 283  */
 284 int clk_disable(struct clk *clk);
 285
 286 /**
 287  * clk_disable_bulk() - Disable (turn off) all clocks in a clock bulk struct.
 288  *
 289  * @bulk:       A clock bulk struct that was previously successfully requested
 290  *              by clk_get_bulk().
 291  * @return zero on success, or -ve error code.
 292  */
 293 int clk_disable_bulk(struct clk_bulk *bulk);
 294
 295 int soc_clk_dump(void);
 296
 297 #endif