80 lines
2.8 KiB
C
80 lines
2.8 KiB
C
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/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* Copyright (C) 2018-2019 SiFive, Inc.
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* Wesley Terpstra
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* Paul Walmsley
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*/
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#ifndef __LINUX_CLK_ANALOGBITS_WRPLL_CLN28HPC_H
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#define __LINUX_CLK_ANALOGBITS_WRPLL_CLN28HPC_H
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#include <linux/types.h>
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/* DIVQ_VALUES: number of valid DIVQ values */
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#define DIVQ_VALUES 6
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/*
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* Bit definitions for struct wrpll_cfg.flags
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*
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* WRPLL_FLAGS_BYPASS_FLAG: if set, the PLL is either in bypass, or should be
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* programmed to enter bypass
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* WRPLL_FLAGS_RESET_FLAG: if set, the PLL is in reset
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* WRPLL_FLAGS_INT_FEEDBACK_FLAG: if set, the PLL is configured for internal
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* feedback mode
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* WRPLL_FLAGS_EXT_FEEDBACK_FLAG: if set, the PLL is configured for external
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* feedback mode (not yet supported by this driver)
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*/
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#define WRPLL_FLAGS_BYPASS_SHIFT 0
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#define WRPLL_FLAGS_BYPASS_MASK BIT(WRPLL_FLAGS_BYPASS_SHIFT)
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#define WRPLL_FLAGS_RESET_SHIFT 1
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#define WRPLL_FLAGS_RESET_MASK BIT(WRPLL_FLAGS_RESET_SHIFT)
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#define WRPLL_FLAGS_INT_FEEDBACK_SHIFT 2
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#define WRPLL_FLAGS_INT_FEEDBACK_MASK BIT(WRPLL_FLAGS_INT_FEEDBACK_SHIFT)
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#define WRPLL_FLAGS_EXT_FEEDBACK_SHIFT 3
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#define WRPLL_FLAGS_EXT_FEEDBACK_MASK BIT(WRPLL_FLAGS_EXT_FEEDBACK_SHIFT)
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/**
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* struct wrpll_cfg - WRPLL configuration values
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* @divr: reference divider value (6 bits), as presented to the PLL signals
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* @divf: feedback divider value (9 bits), as presented to the PLL signals
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* @divq: output divider value (3 bits), as presented to the PLL signals
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* @flags: PLL configuration flags. See above for more information
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* @range: PLL loop filter range. See below for more information
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* @output_rate_cache: cached output rates, swept across DIVQ
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* @parent_rate: PLL refclk rate for which values are valid
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* @max_r: maximum possible R divider value, given @parent_rate
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* @init_r: initial R divider value to start the search from
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*
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* @divr, @divq, @divq, @range represent what the PLL expects to see
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* on its input signals. Thus @divr and @divf are the actual divisors
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* minus one. @divq is a power-of-two divider; for example, 1 =
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* divide-by-2 and 6 = divide-by-64. 0 is an invalid @divq value.
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*
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* When initially passing a struct wrpll_cfg record, the
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* record should be zero-initialized with the exception of the @flags
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* field. The only flag bits that need to be set are either
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* WRPLL_FLAGS_INT_FEEDBACK or WRPLL_FLAGS_EXT_FEEDBACK.
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*/
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struct wrpll_cfg {
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u8 divr;
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u8 divq;
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u8 range;
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u8 flags;
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u16 divf;
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/* private: */
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u32 output_rate_cache[DIVQ_VALUES];
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unsigned long parent_rate;
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u8 max_r;
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u8 init_r;
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};
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int wrpll_configure_for_rate(struct wrpll_cfg *c, u32 target_rate,
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unsigned long parent_rate);
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unsigned int wrpll_calc_max_lock_us(const struct wrpll_cfg *c);
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unsigned long wrpll_calc_output_rate(const struct wrpll_cfg *c,
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unsigned long parent_rate);
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#endif /* __LINUX_CLK_ANALOGBITS_WRPLL_CLN28HPC_H */
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