1 /* SPDX-License-Identifier: BSD-2-Clause */
2 /*
3 * Copyright (c) 2021, Bootlin
4 */
5
6 #ifndef __DRIVERS_CLK_H
7 #define __DRIVERS_CLK_H
8
9 #include <kernel/refcount.h>
10 #include <stdint.h>
11 #include <tee_api_types.h>
12
13 /* Flags for clock */
14 #define CLK_SET_RATE_GATE BIT(0) /* must be gated across rate change */
15 #define CLK_SET_PARENT_GATE BIT(1) /* must be gated across re-parent */
16
17 /**
18 * struct clk - Clock structure
19 *
20 * @name: Clock name
21 * @priv: Private data for the clock provider
22 * @ops: Clock operations
23 * @parent: Current parent
24 * @rate: Current clock rate (cached after init or rate change)
25 * @flags: Specific clock flags
26 * @enabled_count: Enable/disable reference counter
27 * @num_parents: Number of parents
28 * @parents: Array of possible parents of the clock
29 */
30 struct clk {
31 const char *name;
32 void *priv;
33 const struct clk_ops *ops;
34 struct clk *parent;
35 unsigned long rate;
36 unsigned int flags;
37 struct refcount enabled_count;
38 size_t num_parents;
39 struct clk *parents[];
40 };
41
42 /**
43 * struct clk_ops
44 *
45 * @enable: Enable the clock
46 * @disable: Disable the clock
47 * @set_parent: Set the clock parent based on index
48 * @get_parent: Get the current parent index of the clock
49 * @set_rate: Set the clock rate
50 * @get_rate: Get the clock rate
51 * @get_rates_array: Get the supported clock rates as array
52 */
53 struct clk_ops {
54 TEE_Result (*enable)(struct clk *clk);
55 void (*disable)(struct clk *clk);
56 TEE_Result (*set_parent)(struct clk *clk, size_t index);
57 size_t (*get_parent)(struct clk *clk);
58 TEE_Result (*set_rate)(struct clk *clk, unsigned long rate,
59 unsigned long parent_rate);
60 unsigned long (*get_rate)(struct clk *clk,
61 unsigned long parent_rate);
62 TEE_Result (*get_rates_array)(struct clk *clk, size_t start_index,
63 unsigned long *rates, size_t *nb_elts);
64 };
65
66 /**
67 * Return the clock name
68 *
69 * @clk: Clock for which the name is needed
70 * Return a const char * pointing to the clock name
71 */
clk_get_name(struct clk * clk)72 static inline const char *clk_get_name(struct clk *clk)
73 {
74 return clk->name;
75 }
76
77 /**
78 * clk_alloc - Allocate a clock structure
79 *
80 * @name: Clock name
81 * @ops: Clock operations
82 * @parent_clks: Parents of the clock
83 * @parent_count: Number of parents of the clock
84 *
85 * Return a clock struct properly initialized or NULL if allocation failed
86 */
87 struct clk *clk_alloc(const char *name, const struct clk_ops *ops,
88 struct clk **parent_clks, size_t parent_count);
89
90 /**
91 * clk_free - Free a clock structure
92 *
93 * @clk: Clock to be freed or NULL
94 */
95 void clk_free(struct clk *clk);
96
97 /**
98 * clk_register - Register a clock within the clock framework
99 *
100 * @clk: Clock struct to be registered
101 * Return a TEE_Result compliant value
102 */
103 TEE_Result clk_register(struct clk *clk);
104
105 /**
106 * clk_get_rate - Get clock rate
107 *
108 * @clk: Clock for which the rate is needed
109 * Return the clock rate in Hz
110 */
111 unsigned long clk_get_rate(struct clk *clk);
112
113 /**
114 * clk_set_rate - Set a clock rate
115 *
116 * @clk: Clock to be set with the rate
117 * @rate: Rate to set in Hz
118 * Return a TEE_Result compliant value
119 */
120 TEE_Result clk_set_rate(struct clk *clk, unsigned long rate);
121
122 /**
123 * clk_enable - Enable a clock and its ascendance
124 *
125 * @clk: Clock to be enabled
126 * Return a TEE_Result compliant value
127 */
128 TEE_Result clk_enable(struct clk *clk);
129
130 /**
131 * clk_disable - Disable a clock
132 *
133 * @clk: Clock to be disabled
134 */
135 void clk_disable(struct clk *clk);
136
137 /**
138 * clk_is_enabled - Informative state on the clock
139 *
140 * This function is useful during specific system sequences where core
141 * executes atomically (primary core boot, some low power sequences).
142 *
143 * @clk: Clock refernece
144 */
145 bool clk_is_enabled(struct clk *clk);
146
147 /**
148 * clk_get_parent - Get the current clock parent
149 *
150 * @clk: Clock for which the parent is needed
151 * Return the clock parent or NULL if there is no parent
152 */
153 struct clk *clk_get_parent(struct clk *clk);
154
155 /**
156 * clk_get_num_parents - Get the number of parents for a clock
157 *
158 * @clk: Clock for which the number of parents is needed
159 * Return the number of parents
160 */
clk_get_num_parents(struct clk * clk)161 static inline size_t clk_get_num_parents(struct clk *clk)
162 {
163 return clk->num_parents;
164 }
165
166 /**
167 * Get a clock parent by its index
168 *
169 * @clk: Clock for which the parent is needed
170 * @pidx: Parent index for the clock
171 * Return the clock parent at index @pidx or NULL if out of bound
172 */
173 struct clk *clk_get_parent_by_index(struct clk *clk, size_t pidx);
174
175 /**
176 * clk_set_parent - Set the current clock parent
177 *
178 * @clk: Clock for which the parent should be set
179 * @parent: Parent clock to set
180 * Return a TEE_Result compliant value
181 */
182 TEE_Result clk_set_parent(struct clk *clk, struct clk *parent);
183
184 /**
185 * clk_get_rates_array - Get supported rates as an array
186 *
187 * @clk: Clock for which the rates are requested
188 * @start_index: start index of requested rates
189 * @rates: Array of rates allocated by caller or NULL to query count of rates
190 * @nb_elts: Max number of elements that the array can hold as input. Contains
191 * the number of elements that was added in the array as output.
192 * Returns a TEE_Result compliant value
193 */
194 TEE_Result clk_get_rates_array(struct clk *clk, size_t start_index,
195 unsigned long *rates, size_t *nb_elts);
196
197 #endif /* __DRIVERS_CLK_H */
198