clk: sifive: Factor-out PLL library as separate module

To match SiFive clock driver with latest Linux, we factor-out PLL
library as separate module under drivers/clk/analogbits.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>

1 files changed, 101 insertions, 0 deletions

diff --git a/include/linux/clk/analogbits-wrpll-cln28hpc.h b/include/linux/clk/analogbits-wrpll-cln28hpc.h
new file mode 100644
index 0000000000..4432e24749
--- /dev/null
+++ b/include/linux/clk/analogbits-wrpll-cln28hpc.h
@@ -0,0 +1,101 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2019 Western Digital Corporation or its affiliates.
+ *
+ * Copyright (C) 2018 SiFive, Inc.
+ * Wesley Terpstra
+ * Paul Walmsley
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#ifndef __LINUX_CLK_ANALOGBITS_WRPLL_CLN28HPC_H
+#define __LINUX_CLK_ANALOGBITS_WRPLL_CLN28HPC_H
+
+#include <linux/types.h>
+
+/* DIVQ_VALUES: number of valid DIVQ values */
+#define DIVQ_VALUES				6
+
+/*
+ * Bit definitions for struct analogbits_wrpll_cfg.flags
+ *
+ * WRPLL_FLAGS_BYPASS_FLAG: if set, the PLL is either in bypass, or should be
+ *	programmed to enter bypass
+ * WRPLL_FLAGS_RESET_FLAG: if set, the PLL is in reset
+ * WRPLL_FLAGS_INT_FEEDBACK_FLAG: if set, the PLL is configured for internal
+ *	feedback mode
+ * WRPLL_FLAGS_EXT_FEEDBACK_FLAG: if set, the PLL is configured for external
+ *	feedback mode (not yet supported by this driver)
+ *
+ * The flags WRPLL_FLAGS_INT_FEEDBACK_FLAG and WRPLL_FLAGS_EXT_FEEDBACK_FLAG are
+ * mutually exclusive.  If both bits are set, or both are zero, the struct
+ * analogbits_wrpll_cfg record is uninitialized or corrupt.
+ */
+#define WRPLL_FLAGS_BYPASS_SHIFT		0
+#define WRPLL_FLAGS_BYPASS_MASK		BIT(WRPLL_FLAGS_BYPASS_SHIFT)
+#define WRPLL_FLAGS_RESET_SHIFT		1
+#define WRPLL_FLAGS_RESET_MASK		BIT(WRPLL_FLAGS_RESET_SHIFT)
+#define WRPLL_FLAGS_INT_FEEDBACK_SHIFT	2
+#define WRPLL_FLAGS_INT_FEEDBACK_MASK	BIT(WRPLL_FLAGS_INT_FEEDBACK_SHIFT)
+#define WRPLL_FLAGS_EXT_FEEDBACK_SHIFT	3
+#define WRPLL_FLAGS_EXT_FEEDBACK_MASK	BIT(WRPLL_FLAGS_EXT_FEEDBACK_SHIFT)
+
+/**
+ * struct analogbits_wrpll_cfg - WRPLL configuration values
+ * @divr: reference divider value (6 bits), as presented to the PLL signals.
+ * @divf: feedback divider value (9 bits), as presented to the PLL signals.
+ * @divq: output divider value (3 bits), as presented to the PLL signals.
+ * @flags: PLL configuration flags.  See above for more information.
+ * @range: PLL loop filter range.  See below for more information.
+ * @_output_rate_cache: cached output rates, swept across DIVQ.
+ * @_parent_rate: PLL refclk rate for which values are valid
+ * @_max_r: maximum possible R divider value, given @parent_rate
+ * @_init_r: initial R divider value to start the search from
+ *
+ * @divr, @divq, @divq, @range represent what the PLL expects to see
+ * on its input signals.  Thus @divr and @divf are the actual divisors
+ * minus one.  @divq is a power-of-two divider; for example, 1 =
+ * divide-by-2 and 6 = divide-by-64.  0 is an invalid @divq value.
+ *
+ * When initially passing a struct analogbits_wrpll_cfg record, the
+ * record should be zero-initialized with the exception of the @flags
+ * field.  The only flag bits that need to be set are either
+ * WRPLL_FLAGS_INT_FEEDBACK or WRPLL_FLAGS_EXT_FEEDBACK.
+ *
+ * Field names beginning with an underscore should be considered
+ * private to the wrpll-cln28hpc.c code.
+ */
+struct analogbits_wrpll_cfg {
+	u8 divr;
+	u8 divq;
+	u8 range;
+	u8 flags;
+	u16 divf;
+	u32 _output_rate_cache[DIVQ_VALUES];
+	unsigned long _parent_rate;
+	u8 _max_r;
+	u8 _init_r;
+};
+
+/*
+ * Function prototypes
+ */
+
+int analogbits_wrpll_configure_for_rate(struct analogbits_wrpll_cfg *c,
+					u32 target_rate,
+					unsigned long parent_rate);
+
+unsigned int analogbits_wrpll_calc_max_lock_us(struct analogbits_wrpll_cfg *c);
+
+unsigned long analogbits_wrpll_calc_output_rate(struct analogbits_wrpll_cfg *c,
+						unsigned long parent_rate);
+
+#endif /* __LINUX_CLK_ANALOGBITS_WRPLL_CLN28HPC_H */