Simon Glass | f26c8a8 | 2015-06-23 15:39:15 -0600 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (c) 2015 Google, Inc |
| 3 | * Written by Simon Glass <sjg@chromium.org> |
Stephen Warren | 135aa95 | 2016-06-17 09:44:00 -0600 | [diff] [blame] | 4 | * Copyright (c) 2016, NVIDIA CORPORATION. |
Simon Glass | f26c8a8 | 2015-06-23 15:39:15 -0600 | [diff] [blame] | 5 | * |
| 6 | * SPDX-License-Identifier: GPL-2.0+ |
| 7 | */ |
| 8 | |
Michal Simek | 08d0d6f | 2013-11-21 13:39:02 -0800 | [diff] [blame] | 9 | #ifndef _CLK_H_ |
| 10 | #define _CLK_H_ |
| 11 | |
Masahiro Yamada | 1221ce4 | 2016-09-21 11:28:55 +0900 | [diff] [blame] | 12 | #include <linux/errno.h> |
Masahiro Yamada | ad1cf78 | 2016-01-13 13:16:09 +0900 | [diff] [blame] | 13 | #include <linux/types.h> |
| 14 | |
Stephen Warren | 135aa95 | 2016-06-17 09:44:00 -0600 | [diff] [blame] | 15 | /** |
| 16 | * A clock is a hardware signal that oscillates autonomously at a specific |
| 17 | * frequency and duty cycle. Most hardware modules require one or more clock |
| 18 | * signal to drive their operation. Clock signals are typically generated |
| 19 | * externally to the HW module consuming them, by an entity this API calls a |
| 20 | * clock provider. This API provides a standard means for drivers to enable and |
| 21 | * disable clocks, and to set the rate at which they oscillate. |
| 22 | * |
| 23 | * A driver that implements UCLASS_CLOCK is a clock provider. A provider will |
| 24 | * often implement multiple separate clocks, since the hardware it manages |
| 25 | * often has this capability. clock_uclass.h describes the interface which |
| 26 | * clock providers must implement. |
| 27 | * |
| 28 | * Clock consumers/clients are the HW modules driven by the clock signals. This |
| 29 | * header file describes the API used by drivers for those HW modules. |
| 30 | */ |
| 31 | |
Masahiro Yamada | ad1cf78 | 2016-01-13 13:16:09 +0900 | [diff] [blame] | 32 | struct udevice; |
| 33 | |
Stephen Warren | 135aa95 | 2016-06-17 09:44:00 -0600 | [diff] [blame] | 34 | /** |
| 35 | * struct clk - A handle to (allowing control of) a single clock. |
| 36 | * |
| 37 | * Clients provide storage for clock handles. The content of the structure is |
| 38 | * managed solely by the clock API and clock drivers. A clock struct is |
| 39 | * initialized by "get"ing the clock struct. The clock struct is passed to all |
| 40 | * other clock APIs to identify which clock signal to operate upon. |
| 41 | * |
| 42 | * @dev: The device which implements the clock signal. |
| 43 | * @id: The clock signal ID within the provider. |
| 44 | * |
| 45 | * Currently, the clock API assumes that a single integer ID is enough to |
| 46 | * identify and configure any clock signal for any clock provider. If this |
| 47 | * assumption becomes invalid in the future, the struct could be expanded to |
| 48 | * either (a) add more fields to allow clock providers to store additional |
| 49 | * information, or (b) replace the id field with an opaque pointer, which the |
| 50 | * provider would dynamically allocated during its .of_xlate op, and process |
| 51 | * during is .request op. This may require the addition of an extra op to clean |
| 52 | * up the allocation. |
| 53 | */ |
| 54 | struct clk { |
| 55 | struct udevice *dev; |
| 56 | /* |
| 57 | * Written by of_xlate. We assume a single id is enough for now. In the |
| 58 | * future, we might add more fields here. |
Simon Glass | f26c8a8 | 2015-06-23 15:39:15 -0600 | [diff] [blame] | 59 | */ |
Stephen Warren | 135aa95 | 2016-06-17 09:44:00 -0600 | [diff] [blame] | 60 | unsigned long id; |
Simon Glass | f26c8a8 | 2015-06-23 15:39:15 -0600 | [diff] [blame] | 61 | }; |
| 62 | |
Paul Burton | 3f96f87 | 2016-09-08 07:47:28 +0100 | [diff] [blame] | 63 | #if CONFIG_IS_ENABLED(OF_CONTROL) && CONFIG_IS_ENABLED(CLK) |
Simon Glass | 7423daa | 2016-07-04 11:58:03 -0600 | [diff] [blame] | 64 | struct phandle_2_cell; |
| 65 | int clk_get_by_index_platdata(struct udevice *dev, int index, |
| 66 | struct phandle_2_cell *cells, struct clk *clk); |
| 67 | |
Simon Glass | e70cc43 | 2016-01-20 19:43:02 -0700 | [diff] [blame] | 68 | /** |
Stephen Warren | 135aa95 | 2016-06-17 09:44:00 -0600 | [diff] [blame] | 69 | * clock_get_by_index - Get/request a clock by integer index. |
Simon Glass | e70cc43 | 2016-01-20 19:43:02 -0700 | [diff] [blame] | 70 | * |
Stephen Warren | 135aa95 | 2016-06-17 09:44:00 -0600 | [diff] [blame] | 71 | * This looks up and requests a clock. The index is relative to the client |
| 72 | * device; each device is assumed to have n clocks associated with it somehow, |
| 73 | * and this function finds and requests one of them. The mapping of client |
| 74 | * device clock indices to provider clocks may be via device-tree properties, |
| 75 | * board-provided mapping tables, or some other mechanism. |
Simon Glass | e70cc43 | 2016-01-20 19:43:02 -0700 | [diff] [blame] | 76 | * |
Stephen Warren | 135aa95 | 2016-06-17 09:44:00 -0600 | [diff] [blame] | 77 | * @dev: The client device. |
| 78 | * @index: The index of the clock to request, within the client's list of |
| 79 | * clocks. |
| 80 | * @clock A pointer to a clock struct to initialize. |
| 81 | * @return 0 if OK, or a negative error code. |
Simon Glass | e70cc43 | 2016-01-20 19:43:02 -0700 | [diff] [blame] | 82 | */ |
Stephen Warren | 135aa95 | 2016-06-17 09:44:00 -0600 | [diff] [blame] | 83 | int clk_get_by_index(struct udevice *dev, int index, struct clk *clk); |
| 84 | |
| 85 | /** |
| 86 | * clock_get_by_name - Get/request a clock by name. |
| 87 | * |
| 88 | * This looks up and requests a clock. The name is relative to the client |
| 89 | * device; each device is assumed to have n clocks associated with it somehow, |
| 90 | * and this function finds and requests one of them. The mapping of client |
| 91 | * device clock names to provider clocks may be via device-tree properties, |
| 92 | * board-provided mapping tables, or some other mechanism. |
| 93 | * |
| 94 | * @dev: The client device. |
| 95 | * @name: The name of the clock to request, within the client's list of |
| 96 | * clocks. |
| 97 | * @clock: A pointer to a clock struct to initialize. |
| 98 | * @return 0 if OK, or a negative error code. |
| 99 | */ |
| 100 | int clk_get_by_name(struct udevice *dev, const char *name, struct clk *clk); |
Masahiro Yamada | 021abf6 | 2016-09-26 20:45:27 +0900 | [diff] [blame] | 101 | #else |
| 102 | static inline int clk_get_by_index(struct udevice *dev, int index, |
| 103 | struct clk *clk) |
| 104 | { |
| 105 | return -ENOSYS; |
| 106 | } |
| 107 | |
| 108 | static inline int clk_get_by_name(struct udevice *dev, const char *name, |
| 109 | struct clk *clk) |
| 110 | { |
| 111 | return -ENOSYS; |
| 112 | } |
| 113 | #endif |
Simon Glass | e70cc43 | 2016-01-20 19:43:02 -0700 | [diff] [blame] | 114 | |
Stephen Warren | 135aa95 | 2016-06-17 09:44:00 -0600 | [diff] [blame] | 115 | /** |
| 116 | * clk_request - Request a clock by provider-specific ID. |
| 117 | * |
| 118 | * This requests a clock using a provider-specific ID. Generally, this function |
| 119 | * should not be used, since clk_get_by_index/name() provide an interface that |
| 120 | * better separates clients from intimate knowledge of clock providers. |
| 121 | * However, this function may be useful in core SoC-specific code. |
| 122 | * |
| 123 | * @dev: The clock provider device. |
| 124 | * @clock: A pointer to a clock struct to initialize. The caller must |
| 125 | * have already initialized any field in this struct which the |
| 126 | * clock provider uses to identify the clock. |
| 127 | * @return 0 if OK, or a negative error code. |
| 128 | */ |
| 129 | int clk_request(struct udevice *dev, struct clk *clk); |
| 130 | |
| 131 | /** |
| 132 | * clock_free - Free a previously requested clock. |
| 133 | * |
| 134 | * @clock: A clock struct that was previously successfully requested by |
| 135 | * clk_request/get_by_*(). |
| 136 | * @return 0 if OK, or a negative error code. |
| 137 | */ |
| 138 | int clk_free(struct clk *clk); |
| 139 | |
| 140 | /** |
| 141 | * clk_get_rate() - Get current clock rate. |
| 142 | * |
| 143 | * @clk: A clock struct that was previously successfully requested by |
| 144 | * clk_request/get_by_*(). |
| 145 | * @return clock rate in Hz, or -ve error code. |
| 146 | */ |
| 147 | ulong clk_get_rate(struct clk *clk); |
| 148 | |
| 149 | /** |
| 150 | * clk_set_rate() - Set current clock rate. |
| 151 | * |
| 152 | * @clk: A clock struct that was previously successfully requested by |
| 153 | * clk_request/get_by_*(). |
| 154 | * @rate: New clock rate in Hz. |
| 155 | * @return new rate, or -ve error code. |
| 156 | */ |
| 157 | ulong clk_set_rate(struct clk *clk, ulong rate); |
| 158 | |
| 159 | /** |
| 160 | * clk_enable() - Enable (turn on) a clock. |
| 161 | * |
| 162 | * @clk: A clock struct that was previously successfully requested by |
| 163 | * clk_request/get_by_*(). |
| 164 | * @return zero on success, or -ve error code. |
| 165 | */ |
| 166 | int clk_enable(struct clk *clk); |
| 167 | |
| 168 | /** |
| 169 | * clk_disable() - Disable (turn off) a clock. |
| 170 | * |
| 171 | * @clk: A clock struct that was previously successfully requested by |
| 172 | * clk_request/get_by_*(). |
| 173 | * @return zero on success, or -ve error code. |
| 174 | */ |
| 175 | int clk_disable(struct clk *clk); |
| 176 | |
| 177 | int soc_clk_dump(void); |
| 178 | |
| 179 | #endif |