1 // SPDX-License-Identifier: GPL-2.0
3 * Zynq UltraScale+ MPSoC Divider support
5 * Copyright (C) 2016-2019 Xilinx
7 * Adjustable divider clock implementation
10 #include <linux/clk.h>
11 #include <linux/clk-provider.h>
12 #include <linux/slab.h>
13 #include "clk-zynqmp.h"
16 * DOC: basic adjustable divider clock that cannot gate
18 * Traits of this clock:
19 * prepare - clk_prepare only ensures that parents are prepared
20 * enable - clk_enable only ensures that parents are enabled
21 * rate - rate is adjustable. clk->rate = ceiling(parent->rate / divisor)
22 * parent - fixed parent. No clk_set_parent support
25 #define to_zynqmp_clk_divider(_hw) \
26 container_of(_hw, struct zynqmp_clk_divider, hw)
28 #define CLK_FRAC BIT(13) /* has a fractional parent */
29 #define CUSTOM_FLAG_CLK_FRAC BIT(0) /* has a fractional parent in custom type flag */
32 * struct zynqmp_clk_divider - adjustable divider clock
33 * @hw: handle between common and hardware-specific interfaces
34 * @flags: Hardware specific flags
35 * @is_frac: The divider is a fractional divider
36 * @clk_id: Id of clock
37 * @div_type: divisor type (TYPE_DIV1 or TYPE_DIV2)
39 struct zynqmp_clk_divider {
48 static inline int zynqmp_divider_get_val(unsigned long parent_rate,
49 unsigned long rate, u16 flags)
52 unsigned long up_rate, down_rate;
54 if (flags & CLK_DIVIDER_POWER_OF_TWO) {
55 up = DIV_ROUND_UP_ULL((u64)parent_rate, rate);
56 down = DIV_ROUND_DOWN_ULL((u64)parent_rate, rate);
58 up = __roundup_pow_of_two(up);
59 down = __rounddown_pow_of_two(down);
61 up_rate = DIV_ROUND_UP_ULL((u64)parent_rate, up);
62 down_rate = DIV_ROUND_UP_ULL((u64)parent_rate, down);
64 return (rate - up_rate) <= (down_rate - rate) ? up : down;
67 return DIV_ROUND_CLOSEST(parent_rate, rate);
72 * zynqmp_clk_divider_recalc_rate() - Recalc rate of divider clock
73 * @hw: handle between common and hardware-specific interfaces
74 * @parent_rate: rate of parent clock
76 * Return: 0 on success else error+reason
78 static unsigned long zynqmp_clk_divider_recalc_rate(struct clk_hw *hw,
79 unsigned long parent_rate)
81 struct zynqmp_clk_divider *divider = to_zynqmp_clk_divider(hw);
82 const char *clk_name = clk_hw_get_name(hw);
83 u32 clk_id = divider->clk_id;
84 u32 div_type = divider->div_type;
88 ret = zynqmp_pm_clock_getdivider(clk_id, &div);
91 pr_warn_once("%s() get divider failed for %s, ret = %d\n",
92 __func__, clk_name, ret);
94 if (div_type == TYPE_DIV1)
99 if (divider->flags & CLK_DIVIDER_POWER_OF_TWO)
103 WARN(!(divider->flags & CLK_DIVIDER_ALLOW_ZERO),
104 "%s: Zero divisor and CLK_DIVIDER_ALLOW_ZERO not set\n",
109 return DIV_ROUND_UP_ULL(parent_rate, value);
113 * zynqmp_clk_divider_round_rate() - Round rate of divider clock
114 * @hw: handle between common and hardware-specific interfaces
115 * @rate: rate of clock to be set
116 * @prate: rate of parent clock
118 * Return: 0 on success else error+reason
120 static long zynqmp_clk_divider_round_rate(struct clk_hw *hw,
122 unsigned long *prate)
124 struct zynqmp_clk_divider *divider = to_zynqmp_clk_divider(hw);
125 const char *clk_name = clk_hw_get_name(hw);
126 u32 clk_id = divider->clk_id;
127 u32 div_type = divider->div_type;
132 /* if read only, just return current value */
133 if (divider->flags & CLK_DIVIDER_READ_ONLY) {
134 ret = zynqmp_pm_clock_getdivider(clk_id, &bestdiv);
137 pr_warn_once("%s() get divider failed for %s, ret = %d\n",
138 __func__, clk_name, ret);
139 if (div_type == TYPE_DIV1)
140 bestdiv = bestdiv & 0xFFFF;
142 bestdiv = bestdiv >> 16;
144 if (divider->flags & CLK_DIVIDER_POWER_OF_TWO)
145 bestdiv = 1 << bestdiv;
147 return DIV_ROUND_UP_ULL((u64)*prate, bestdiv);
150 width = fls(divider->max_div);
152 rate = divider_round_rate(hw, rate, prate, NULL, width, divider->flags);
154 if (divider->is_frac && (clk_hw_get_flags(hw) & CLK_SET_RATE_PARENT) && (rate % *prate))
161 * zynqmp_clk_divider_set_rate() - Set rate of divider clock
162 * @hw: handle between common and hardware-specific interfaces
163 * @rate: rate of clock to be set
164 * @parent_rate: rate of parent clock
166 * Return: 0 on success else error+reason
168 static int zynqmp_clk_divider_set_rate(struct clk_hw *hw, unsigned long rate,
169 unsigned long parent_rate)
171 struct zynqmp_clk_divider *divider = to_zynqmp_clk_divider(hw);
172 const char *clk_name = clk_hw_get_name(hw);
173 u32 clk_id = divider->clk_id;
174 u32 div_type = divider->div_type;
178 value = zynqmp_divider_get_val(parent_rate, rate, divider->flags);
179 if (div_type == TYPE_DIV1) {
180 div = value & 0xFFFF;
187 if (divider->flags & CLK_DIVIDER_POWER_OF_TWO)
190 ret = zynqmp_pm_clock_setdivider(clk_id, div);
193 pr_warn_once("%s() set divider failed for %s, ret = %d\n",
194 __func__, clk_name, ret);
199 static const struct clk_ops zynqmp_clk_divider_ops = {
200 .recalc_rate = zynqmp_clk_divider_recalc_rate,
201 .round_rate = zynqmp_clk_divider_round_rate,
202 .set_rate = zynqmp_clk_divider_set_rate,
206 * zynqmp_clk_get_max_divisor() - Get maximum supported divisor from firmware.
207 * @clk_id: Id of clock
208 * @type: Divider type
210 * Return: Maximum divisor of a clock if query data is successful
211 * U16_MAX in case of query data is not success
213 static u32 zynqmp_clk_get_max_divisor(u32 clk_id, u32 type)
215 struct zynqmp_pm_query_data qdata = {0};
216 u32 ret_payload[PAYLOAD_ARG_CNT];
219 qdata.qid = PM_QID_CLOCK_GET_MAX_DIVISOR;
222 ret = zynqmp_pm_query_data(qdata, ret_payload);
224 * To maintain backward compatibility return maximum possible value
225 * (0xFFFF) if query for max divisor is not successful.
230 return ret_payload[1];
234 * zynqmp_clk_register_divider() - Register a divider clock
235 * @name: Name of this clock
236 * @clk_id: Id of clock
237 * @parents: Name of this clock's parents
238 * @num_parents: Number of parents
239 * @nodes: Clock topology node
241 * Return: clock hardware to registered clock divider
243 struct clk_hw *zynqmp_clk_register_divider(const char *name,
245 const char * const *parents,
247 const struct clock_topology *nodes)
249 struct zynqmp_clk_divider *div;
251 struct clk_init_data init;
254 /* allocate the divider */
255 div = kzalloc(sizeof(*div), GFP_KERNEL);
257 return ERR_PTR(-ENOMEM);
260 init.ops = &zynqmp_clk_divider_ops;
261 /* CLK_FRAC is not defined in the common clk framework */
262 init.flags = nodes->flag & ~CLK_FRAC;
263 init.parent_names = parents;
264 init.num_parents = 1;
266 /* struct clk_divider assignments */
267 div->is_frac = !!((nodes->flag & CLK_FRAC) |
268 (nodes->custom_type_flag & CUSTOM_FLAG_CLK_FRAC));
269 div->flags = nodes->type_flag;
270 div->hw.init = &init;
271 div->clk_id = clk_id;
272 div->div_type = nodes->type;
275 * To achieve best possible rate, maximum limit of divider is required
278 div->max_div = zynqmp_clk_get_max_divisor(clk_id, nodes->type);
281 ret = clk_hw_register(NULL, hw);