1 // SPDX-License-Identifier: GPL-2.0
3  * Zynq UltraScale+ MPSoC Divider support
5  *  Copyright (C) 2016-2019 Xilinx
7  * Adjustable divider clock implementation
11 #include <linux/clk-provider.h>
13 #include "clk-zynqmp.h"
16  * DOC: basic adjustable divider clock that cannot gate
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
32  * struct zynqmp_clk_divider - adjustable divider clock
33  * @hw:		handle between common and hardware-specific interfaces
35  * @is_frac:	The divider is a fractional divider
64 		return (rate - up_rate) <= (down_rate - rate) ? up : down;  in zynqmp_divider_get_val()
72  * zynqmp_clk_divider_recalc_rate() - Recalc rate of divider clock
73  * @hw:			handle between common and hardware-specific interfaces
81 	struct zynqmp_clk_divider *divider = to_zynqmp_clk_divider(hw);  in zynqmp_clk_divider_recalc_rate()  local
83 	u32 clk_id = divider->clk_id;  in zynqmp_clk_divider_recalc_rate()
84 	u32 div_type = divider->div_type;  in zynqmp_clk_divider_recalc_rate()
91 		pr_warn_once("%s() get divider failed for %s, ret = %d\n",  in zynqmp_clk_divider_recalc_rate()
99 	if (divider->flags & CLK_DIVIDER_POWER_OF_TWO)  in zynqmp_clk_divider_recalc_rate()
103 		WARN(!(divider->flags & CLK_DIVIDER_ALLOW_ZERO),  in zynqmp_clk_divider_recalc_rate()
114 				    struct zynqmp_clk_divider *divider,  in zynqmp_get_divider2_val()  argument
135 	for (div1 = 1; div1 <= pdivider->max_div;) {  in zynqmp_get_divider2_val()
136 		for (div2 = 1; div2 <= divider->max_div;) {  in zynqmp_get_divider2_val()
137 			long new_error = ((div1_prate / div1) / div2) - rate;  in zynqmp_get_divider2_val()
143 			if (divider->flags & CLK_DIVIDER_POWER_OF_TWO)  in zynqmp_get_divider2_val()
148 		if (pdivider->flags & CLK_DIVIDER_POWER_OF_TWO)  in zynqmp_get_divider2_val()
156  * zynqmp_clk_divider_round_rate() - Round rate of divider clock
157  * @hw:			handle between common and hardware-specific interfaces
167 	struct zynqmp_clk_divider *divider = to_zynqmp_clk_divider(hw);  in zynqmp_clk_divider_round_rate()  local
169 	u32 clk_id = divider->clk_id;  in zynqmp_clk_divider_round_rate()
170 	u32 div_type = divider->div_type;  in zynqmp_clk_divider_round_rate()
175 	if (divider->flags & CLK_DIVIDER_READ_ONLY) {  in zynqmp_clk_divider_round_rate()
179 			pr_warn_once("%s() get divider failed for %s, ret = %d\n",  in zynqmp_clk_divider_round_rate()
186 		if (divider->flags & CLK_DIVIDER_POWER_OF_TWO)  in zynqmp_clk_divider_round_rate()
192 	bestdiv = zynqmp_divider_get_val(*prate, rate, divider->flags);  in zynqmp_clk_divider_round_rate()
195 	 * In case of two divisors, compute best divider values and return  in zynqmp_clk_divider_round_rate()
197 	 * set to optimum based on required total divider value.  in zynqmp_clk_divider_round_rate()
201 		zynqmp_get_divider2_val(hw, rate, divider, &bestdiv);  in zynqmp_clk_divider_round_rate()
204 	if ((clk_hw_get_flags(hw) & CLK_SET_RATE_PARENT) && divider->is_frac)  in zynqmp_clk_divider_round_rate()
207 	bestdiv = min_t(u32, bestdiv, divider->max_div);  in zynqmp_clk_divider_round_rate()
214  * zynqmp_clk_divider_set_rate() - Set rate of divider clock
215  * @hw:			handle between common and hardware-specific interfaces
224 	struct zynqmp_clk_divider *divider = to_zynqmp_clk_divider(hw);  in zynqmp_clk_divider_set_rate()  local
226 	u32 clk_id = divider->clk_id;  in zynqmp_clk_divider_set_rate()
227 	u32 div_type = divider->div_type;  in zynqmp_clk_divider_set_rate()
231 	value = zynqmp_divider_get_val(parent_rate, rate, divider->flags);  in zynqmp_clk_divider_set_rate()
240 	if (divider->flags & CLK_DIVIDER_POWER_OF_TWO)  in zynqmp_clk_divider_set_rate()
246 		pr_warn_once("%s() set divider failed for %s, ret = %d\n",  in zynqmp_clk_divider_set_rate()
259  * zynqmp_clk_get_max_divisor() - Get maximum supported divisor from firmware.
261  * @type:		Divider type
287  * zynqmp_clk_register_divider() - Register a divider clock
294  * Return: clock hardware to registered clock divider
307 	/* allocate the divider */  in zynqmp_clk_register_divider()
310 		return ERR_PTR(-ENOMEM);  in zynqmp_clk_register_divider()
315 	init.flags = nodes->flag & ~CLK_FRAC;  in zynqmp_clk_register_divider()
320 	div->is_frac = !!((nodes->flag & CLK_FRAC) |  in zynqmp_clk_register_divider()
321 			  (nodes->custom_type_flag & CUSTOM_FLAG_CLK_FRAC));  in zynqmp_clk_register_divider()
322 	div->flags = nodes->type_flag;  in zynqmp_clk_register_divider()
323 	div->hw.init = &init;  in zynqmp_clk_register_divider()
324 	div->clk_id = clk_id;  in zynqmp_clk_register_divider()
325 	div->div_type = nodes->type;  in zynqmp_clk_register_divider()
328 	 * To achieve best possible rate, maximum limit of divider is required  in zynqmp_clk_register_divider()
331 	div->max_div = zynqmp_clk_get_max_divisor(clk_id, nodes->type);  in zynqmp_clk_register_divider()
333 	hw = &div->hw;  in zynqmp_clk_register_divider()