[PATCH 0/3] clk: add driver for the SiFive FU540 PRCI and PLLs it controls

[PATCH 0/3] clk: add driver for the SiFive FU540 PRCI and PLLs it controls

[Paul Walmsley]

Add a driver for the SiFive FU540 PRCI IP block, which handles clock and
some device reset control for the SiFive FU540 chip.  Also add a driver-
independent library for the Analog Bits Wide-Range PLL (WRPLL), used by
the PRCI driver to monitor and control the WRPLL instances on the FU540
chip.

It's been a long time since I've worked on Linux clock code, so Mike &
Stephen, I'd appreciate a close look at the PRCI driver to make sure
what it's doing makes sense.

Boot-tested on a SiFive HiFive Unleashed board.  COREPLL rate changes
and notification were also tested on the same board.

This patch series is also available at:

https://github.com/sifive/riscv-linux/tree/dev/paulw/prci-v4.19-rc7


Paul Walmsley (3):
  clk: analogbits: add Wide-Range PLL library
  dt-bindings: clk: add documentation for the SiFive PRCI driver
  clk: sifive: add a driver for the SiFive FU540 PRCI IP block

 .../bindings/clock/sifive/fu540-prci.txt      |  40 ++
 MAINTAINERS                                   |   6 +
 drivers/clk/Kconfig                           |   2 +
 drivers/clk/Makefile                          |   2 +
 drivers/clk/analogbits/Kconfig                |   3 +
 drivers/clk/analogbits/Makefile               |   2 +
 drivers/clk/analogbits/wrpll-cln28hpc.c       | 387 +++++++++++
 drivers/clk/sifive/Kconfig                    |  18 +
 drivers/clk/sifive/Makefile                   |   1 +
 drivers/clk/sifive/fu540-prci.c               | 634 ++++++++++++++++++
 include/linux/clk/analogbits-wrpll-cln28hpc.h |  99 +++
 include/linux/clk/sifive-fu540-prci.h         |  27 +
 12 files changed, 1221 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/clock/sifive/fu540-prci.txt
 create mode 100644 drivers/clk/analogbits/Kconfig
 create mode 100644 drivers/clk/analogbits/Makefile
 create mode 100644 drivers/clk/analogbits/wrpll-cln28hpc.c
 create mode 100644 drivers/clk/sifive/Kconfig
 create mode 100644 drivers/clk/sifive/Makefile
 create mode 100644 drivers/clk/sifive/fu540-prci.c
 create mode 100644 include/linux/clk/analogbits-wrpll-cln28hpc.h
 create mode 100644 include/linux/clk/sifive-fu540-prci.h

Cc: Michael Turquette <mturquette@baylibre.com>
Cc: Stephen Boyd <sboyd@kernel.org>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Wesley W. Terpstra <wesley@sifive.com>
Cc: Palmer Dabbelt <palmer@sifive.com>
Cc: Megan Wachs <megan@sifive.com>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: devicetree@vger.kernel.org
Cc: linux-riscv@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-clk@vger.kernel.org

-- 
2.19.1

[PATCH 1/3] clk: analogbits: add Wide-Range PLL library

[Paul Walmsley]

Add common library code for the Analog Bits Wide-Range PLL (WRPLL) as
implemented in TSMC CLN28HPC.

There is no bus interface or register target associated with this PLL.
This library is intended to be used by drivers for IP blocks that
expose registers connected to the PLL configuration and status
signals.

Based on code originally written by Wesley Terpstra
<wesley@sifive.com>:
https://github.com/riscv/riscv-linux/commit/999529edf517ed75b56659d456d221b2ee56bb60

Cc: Wesley Terpstra <wesley@sifive.com>
Cc: Palmer Dabbelt <palmer@sifive.com>
Cc: Michael Turquette <mturquette@baylibre.com>
Cc: Stephen Boyd <sboyd@kernel.org>
Cc: Megan Wachs <megan@sifive.com>                                                                                                                    Cc: linux-clk@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Paul Walmsley <paul.walmsley@sifive.com>
Signed-off-by: Paul Walmsley <paul@pwsan.com>
---
 MAINTAINERS                                   |   6 +
 drivers/clk/Kconfig                           |   1 +
 drivers/clk/Makefile                          |   1 +
 drivers/clk/analogbits/Kconfig                |   3 +
 drivers/clk/analogbits/Makefile               |   2 +
 drivers/clk/analogbits/wrpll-cln28hpc.c       | 387 ++++++++++++++++++
 include/linux/clk/analogbits-wrpll-cln28hpc.h |  99 +++++
 7 files changed, 499 insertions(+)
 create mode 100644 drivers/clk/analogbits/Kconfig
 create mode 100644 drivers/clk/analogbits/Makefile
 create mode 100644 drivers/clk/analogbits/wrpll-cln28hpc.c
 create mode 100644 include/linux/clk/analogbits-wrpll-cln28hpc.h

diff --git a/MAINTAINERS b/MAINTAINERS
index 48a65c3a4189..02c7b2b72a6e 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -911,6 +911,12 @@ F:	drivers/iio/adc/ltc2497*
 X:	drivers/iio/*/adjd*
 F:	drivers/staging/iio/*/ad*
 
+ANALOGBITS PLL LIBRARIES
+M:	Paul Walmsley <paul.walmsley@sifive.com>
+S:	Supported
+F:	drivers/clk/analogbits/*
+F:	include/linux/clk/analogbits*
+
 ANDES ARCHITECTURE
 M:	Greentime Hu <green.hu@gmail.com>
 M:	Vincent Chen <deanbo422@gmail.com>
diff --git a/drivers/clk/Kconfig b/drivers/clk/Kconfig
index 292056bbb30e..a34ccfcb54ac 100644
--- a/drivers/clk/Kconfig
+++ b/drivers/clk/Kconfig
@@ -284,6 +284,7 @@ config COMMON_CLK_STM32H7
 	  Support for stm32h7 SoC family clocks
 
 source "drivers/clk/actions/Kconfig"
+source "drivers/clk/analogbits/Kconfig"
 source "drivers/clk/bcm/Kconfig"
 source "drivers/clk/hisilicon/Kconfig"
 source "drivers/clk/imgtec/Kconfig"
diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile
index a84c5573cabe..d59c11ddfc5e 100644
--- a/drivers/clk/Makefile
+++ b/drivers/clk/Makefile
@@ -62,6 +62,7 @@ obj-$(CONFIG_COMMON_CLK_XGENE)		+= clk-xgene.o
 
 # please keep this section sorted lexicographically by directory path name
 obj-y					+= actions/
+obj-y					+= analogbits/
 obj-$(CONFIG_COMMON_CLK_AT91)		+= at91/
 obj-$(CONFIG_ARCH_ARTPEC)		+= axis/
 obj-$(CONFIG_ARC_PLAT_AXS10X)		+= axs10x/
diff --git a/drivers/clk/analogbits/Kconfig b/drivers/clk/analogbits/Kconfig
new file mode 100644
index 000000000000..5ccf7902f6e2
--- /dev/null
+++ b/drivers/clk/analogbits/Kconfig
@@ -0,0 +1,3 @@
+config CLK_ANALOGBITS_WRPLL_CLN28HPC
+	bool
+
diff --git a/drivers/clk/analogbits/Makefile b/drivers/clk/analogbits/Makefile
new file mode 100644
index 000000000000..d3c102c8b4e0
--- /dev/null
+++ b/drivers/clk/analogbits/Makefile
@@ -0,0 +1,2 @@
+obj-$(CONFIG_CLK_ANALOGBITS_WRPLL_CLN28HPC)	+= wrpll-cln28hpc.o
+
diff --git a/drivers/clk/analogbits/wrpll-cln28hpc.c b/drivers/clk/analogbits/wrpll-cln28hpc.c
new file mode 100644
index 000000000000..ebdef859cbf5
--- /dev/null
+++ b/drivers/clk/analogbits/wrpll-cln28hpc.c
@@ -0,0 +1,387 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * 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.
+ *
+ * This library supports configuration parsing and reprogramming of
+ * the CLN28HPC variant of the Analog Bits Wide Range PLL.  The
+ * intention is for this library to be reusable for any device that
+ * integrates this PLL; thus the register structure and programming
+ * details are expected to be provided by a separate IP block driver.
+ *
+ * The bulk of this code is primarily useful for clock configurations
+ * that must operate at arbitrary rates, as opposed to clock configurations
+ * that are restricted by software or manufacturer guidance to a small,
+ * pre-determined set of performance points.
+ *
+ * References:
+ * - Analog Bits "Wide Range PLL Datasheet", version 2015.10.01
+ * - SiFive FU540-C000 Manual v1p0, Chapter 7 "Clocking and Reset"
+ */
+
+#include <linux/bug.h>
+#include <linux/err.h>
+#include <linux/log2.h>
+#include <linux/math64.h>
+#include <linux/clk/analogbits-wrpll-cln28hpc.h>
+
+/* MIN_INPUT_FREQ: minimum input clock frequency, in Hz (Fref_min) */
+#define MIN_INPUT_FREQ			7000000
+
+/* MAX_INPUT_FREQ: maximum input clock frequency, in Hz (Fref_max) */
+#define MAX_INPUT_FREQ			600000000
+
+/* MIN_POST_DIVIDE_REF_FREQ: minimum post-divider reference frequency, in Hz */
+#define MIN_POST_DIVR_FREQ		7000000
+
+/* MAX_POST_DIVIDE_REF_FREQ: maximum post-divider reference frequency, in Hz */
+#define MAX_POST_DIVR_FREQ		200000000
+
+/* MIN_VCO_FREQ: minimum VCO frequency, in Hz (Fvco_min) */
+#define MIN_VCO_FREQ			2400000000UL
+
+/* MAX_VCO_FREQ: maximum VCO frequency, in Hz (Fvco_max) */
+#define MAX_VCO_FREQ			4800000000ULL
+
+/* MAX_DIVQ_DIVISOR: maximum output divisor.  Selected by DIVQ = 6 */
+#define MAX_DIVQ_DIVISOR		64
+
+/* MAX_DIVR_DIVISOR: maximum reference divisor.  Selected by DIVR = 63 */
+#define MAX_DIVR_DIVISOR		64
+
+/* MAX_LOCK_US: maximum PLL lock time, in microseconds (tLOCK_max) */
+#define MAX_LOCK_US			70
+
+/*
+ * ROUND_SHIFT: number of bits to shift to avoid precision loss in the rounding
+ *              algorithm
+ */
+#define ROUND_SHIFT			20
+
+/*
+ * Private functions
+ */
+
+/**
+ * __wrpll_calc_filter_range() - determine PLL loop filter bandwidth
+ * @post_divr_freq: input clock rate after the R divider
+ *
+ * Select the value to be presented to the PLL RANGE input signals, based
+ * on the input clock frequency after the post-R-divider @post_divr_freq.
+ * This code follows the recommendations in the PLL datasheet for filter
+ * range selection.
+ *
+ * Return: The RANGE value to be presented to the PLL configuration inputs,
+ *         or -1 upon error.
+ */
+static int __wrpll_calc_filter_range(unsigned long post_divr_freq)
+{
+	u8 range;
+
+	if (post_divr_freq < MIN_POST_DIVR_FREQ ||
+	    post_divr_freq > MAX_POST_DIVR_FREQ) {
+		WARN(1, "%s: post-divider reference freq out of range: %lu",
+		     __func__, post_divr_freq);
+		return -1;
+	}
+
+	if (post_divr_freq < 11000000)
+		range = 1;
+	else if (post_divr_freq < 18000000)
+		range = 2;
+	else if (post_divr_freq < 30000000)
+		range = 3;
+	else if (post_divr_freq < 50000000)
+		range = 4;
+	else if (post_divr_freq < 80000000)
+		range = 5;
+	else if (post_divr_freq < 130000000)
+		range = 6;
+	else
+		range = 7;
+
+	return range;
+}
+
+/**
+ * __wrpll_calc_fbdiv() - return feedback fixed divide value
+ * @c: ptr to a struct analogbits_wrpll_cfg record to read from
+ *
+ * The internal feedback path includes a fixed by-two divider; the
+ * external feedback path does not.  Return the appropriate divider
+ * value (2 or 1) depending on whether internal or external feedback
+ * is enabled.  This code doesn't test for invalid configurations
+ * (e.g. both or neither of WRPLL_FLAGS_*_FEEDBACK are set); it relies
+ * on the caller to do so.
+ *
+ * Context: Any context.  Caller must protect the memory pointed to by
+ *          @c from simultaneous modification.
+ *
+ * Return: 2 if internal feedback is enabled or 1 if external feedback
+ *         is enabled.
+ */
+static u8 __wrpll_calc_fbdiv(struct analogbits_wrpll_cfg *c)
+{
+	return (c->flags & WRPLL_FLAGS_INT_FEEDBACK_MASK) ? 2 : 1;
+}
+
+/**
+ * __wrpll_calc_divq() - determine DIVQ based on target PLL output clock rate
+ * @target_rate: target PLL output clock rate
+ * @vco_rate: pointer to a u64 to store the computed VCO rate into
+ *
+ * Determine a reasonable value for the PLL Q post-divider, based on the
+ * target output rate @target_rate for the PLL.  Along with returning the
+ * computed Q divider value as the return value, this function stores the
+ * desired target VCO rate into the variable pointed to by @vco_rate.
+ *
+ * Context: Any context.  Caller must protect the memory pointed to by
+ *          @vco_rate from simultaneous access or modification.
+ *
+ * Return: a positive integer DIVQ value to be programmed into the hardware
+ *         upon success, or 0 upon error (since 0 is an invalid DIVQ value)
+ */
+static u8 __wrpll_calc_divq(u32 target_rate, u64 *vco_rate)
+{
+	u64 s;
+	u8 divq = 0;
+
+	if (!vco_rate) {
+		WARN_ON(1);
+		goto wcd_out;
+	}
+
+	s = div_u64(MAX_VCO_FREQ, target_rate);
+	if (s <= 1) {
+		divq = 1;
+		*vco_rate = MAX_VCO_FREQ;
+	} else if (s > MAX_DIVQ_DIVISOR) {
+		divq = ilog2(MAX_DIVQ_DIVISOR);
+		*vco_rate = MIN_VCO_FREQ;
+	} else {
+		divq = ilog2(s);
+		*vco_rate = target_rate << divq;
+	}
+
+wcd_out:
+	return divq;
+}
+
+/**
+ * __wrpll_update_parent_rate() - update PLL data when parent rate changes
+ * @c: ptr to a struct analogbits_wrpll_cfg record to write PLL data to
+ * @parent_rate: PLL input refclk rate (pre-R-divider)
+ *
+ * Pre-compute some data used by the PLL configuration algorithm when
+ * the PLL's reference clock rate changes.  The intention is to avoid
+ * computation when the parent rate remains constant - expected to be
+ * the common case.
+ *
+ * Returns: 0 upon success or -1 if the reference clock rate is out of range.
+ */
+static int __wrpll_update_parent_rate(struct analogbits_wrpll_cfg *c,
+				      unsigned long parent_rate)
+{
+	u8 max_r_for_parent;
+
+	if (parent_rate > MAX_INPUT_FREQ || parent_rate < MIN_POST_DIVR_FREQ)
+		return -1;
+
+	c->_parent_rate = parent_rate;
+	max_r_for_parent = div_u64(parent_rate, MIN_POST_DIVR_FREQ);
+	c->_max_r = min_t(u8, MAX_DIVR_DIVISOR, max_r_for_parent);
+
+	/* Round up */
+	c->_init_r = div_u64(parent_rate + MAX_POST_DIVR_FREQ - 1,
+			     MAX_POST_DIVR_FREQ);
+
+	return 0;
+}
+
+/*
+ * Public functions
+ */
+
+/**
+ * analogbits_wrpll_configure() - compute PLL configuration for a target rate
+ * @c: ptr to a struct analogbits_wrpll_cfg record to write into
+ * @target_rate: target PLL output clock rate (post-Q-divider)
+ * @parent_rate: PLL input refclk rate (pre-R-divider)
+ *
+ * Given a pointer to a PLL context @c, a desired PLL target output
+ * rate @target_rate, and a reference clock input rate @parent_rate,
+ * compute the appropriate PLL signal configuration values.  PLL
+ * reprogramming is not glitchless, so the caller should switch any
+ * downstream logic to a different clock source or clock-gate it
+ * before presenting these values to the PLL configuration signals.
+ *
+ * The caller must pass this function a pre-initialized struct
+ * analogbits_wrpll_cfg record: either initialized to zero (with the
+ * exception of the .name and .flags fields) or read from the PLL.
+ *
+ * Context: Any context.  Caller must protect the memory pointed to by @c
+ *          from simultaneous access or modification.
+ *
+ * Return: 0 upon success; anything else upon failure.
+ */
+int analogbits_wrpll_configure_for_rate(struct analogbits_wrpll_cfg *c,
+					u32 target_rate,
+					unsigned long parent_rate)
+{
+	unsigned long ratio;
+	u64 target_vco_rate, delta, best_delta, f_pre_div, vco, vco_pre;
+	u32 best_f, f, post_divr_freq, fbcfg;
+	u8 fbdiv, divq, best_r, r;
+
+	if (!c)
+		return -1;
+
+	if (c->flags == 0) {
+		WARN(1, "%s called with uninitialized PLL config", __func__);
+		return -1;
+	}
+
+	fbcfg = WRPLL_FLAGS_INT_FEEDBACK_MASK | WRPLL_FLAGS_EXT_FEEDBACK_MASK;
+	if ((c->flags & fbcfg) == fbcfg) {
+		WARN(1, "%s called with invalid PLL config", __func__);
+		return -1;
+	}
+
+	if (c->flags == WRPLL_FLAGS_EXT_FEEDBACK_MASK) {
+		WARN(1, "%s: external feedback mode not currently supported",
+		     __func__);
+		return -1;
+	}
+
+	/* Initialize rounding data if it hasn't been initialized already */
+	if (parent_rate != c->_parent_rate) {
+		if (__wrpll_update_parent_rate(c, parent_rate)) {
+			pr_err("%s: PLL input rate is out of range\n",
+			       __func__);
+			return -1;
+		}
+	}
+
+	c->flags &= ~WRPLL_FLAGS_RESET_MASK;
+
+	/* Put the PLL into bypass if the user requests the parent clock rate */
+	if (target_rate == parent_rate) {
+		c->flags |= WRPLL_FLAGS_BYPASS_MASK;
+		return 0;
+	}
+	c->flags &= ~WRPLL_FLAGS_BYPASS_MASK;
+
+	/* Calculate the Q shift and target VCO rate */
+	divq = __wrpll_calc_divq(target_rate, &target_vco_rate);
+	if (divq == 0)
+		return -1;
+	c->divq = divq;
+
+	/* Precalculate the pre-Q divider target ratio */
+	ratio = div64_u64((target_vco_rate << ROUND_SHIFT), parent_rate);
+
+	fbdiv = __wrpll_calc_fbdiv(c);
+	best_r = 0;
+	best_f = 0;
+	best_delta = MAX_VCO_FREQ;
+
+	/*
+	 * Consider all values for R which land within
+	 * [MIN_POST_DIVR_FREQ, MAX_POST_DIVR_FREQ]; prefer smaller R
+	 */
+	for (r = c->_init_r; r <= c->_max_r; ++r) {
+		/* What is the best F we can pick in this case? */
+		f_pre_div = ratio * r;
+		f = (f_pre_div + (1 << ROUND_SHIFT)) >> ROUND_SHIFT;
+		f >>= (fbdiv - 1);
+
+		post_divr_freq = div_u64(parent_rate, r);
+		vco_pre = fbdiv * post_divr_freq;
+		vco = vco_pre * f;
+
+		/* Ensure rounding didn't take us out of range */
+		if (vco > target_vco_rate) {
+			--f;
+			vco = vco_pre * f;
+		} else if (vco < MIN_VCO_FREQ) {
+			++f;
+			vco = vco_pre * f;
+		}
+
+		delta = abs(target_rate - vco);
+		if (delta < best_delta) {
+			best_delta = delta;
+			best_r = r;
+			best_f = f;
+		}
+	}
+
+	c->divr = best_r - 1;
+	c->divf = best_f - 1;
+
+	post_divr_freq = div_u64(parent_rate, best_r);
+
+	/* Pick the best PLL jitter filter */
+	c->range = __wrpll_calc_filter_range(post_divr_freq);
+
+	return 0;
+}
+
+/**
+ * analogbits_wrpll_calc_output_rate() - calculate the PLL's target output rate
+ * @c: ptr to a struct analogbits_wrpll_cfg record to read from
+ * @parent_rate: PLL refclk rate
+ *
+ * Given a pointer to the PLL's current input configuration @c and the
+ * PLL's input reference clock rate @parent_rate (before the R
+ * pre-divider), calculate the PLL's output clock rate (after the Q
+ * post-divider)
+ *
+ * Context: Any context.  Caller must protect the memory pointed to by @c
+ *          from simultaneous modification.
+ *
+ * Return: the PLL's output clock rate, in Hz.
+ */
+unsigned long analogbits_wrpll_calc_output_rate(struct analogbits_wrpll_cfg *c,
+						unsigned long parent_rate)
+{
+	u8 fbdiv;
+	u64 n;
+
+	WARN(c->flags & WRPLL_FLAGS_EXT_FEEDBACK_MASK,
+	     "external feedback mode not yet supported");
+
+	fbdiv = __wrpll_calc_fbdiv(c);
+	n = parent_rate * fbdiv * (c->divf + 1);
+	n = div_u64(n, (c->divr + 1));
+	n >>= c->divq;
+
+	return n;
+}
+
+/**
+ * analogbits_wrpll_calc_max_lock_us() - return the time for the PLL to lock
+ * @c: ptr to a struct analogbits_wrpll_cfg record to read from
+ *
+ * Return the minimum amount of time (in microseconds) that the caller
+ * must wait after reprogramming the PLL to ensure that it is locked
+ * to the input frequency and stable.  This is likely to depend on the DIVR
+ * value; this is under discussion with the manufacturer.
+ *
+ * Return: the minimum amount of time the caller must wait for the PLL
+ *         to lock (in microseconds)
+ */
+unsigned int analogbits_wrpll_calc_max_lock_us(struct analogbits_wrpll_cfg *c)
+{
+	return MAX_LOCK_US;
+}
diff --git a/include/linux/clk/analogbits-wrpll-cln28hpc.h b/include/linux/clk/analogbits-wrpll-cln28hpc.h
new file mode 100644
index 000000000000..cc4268f16067
--- /dev/null
+++ b/include/linux/clk/analogbits-wrpll-cln28hpc.h
@@ -0,0 +1,99 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * 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 */
-- 
2.19.1

[PATCH 2/3] dt-bindings: clk: add documentation for the SiFive PRCI driver

[Paul Walmsley]

Add DT binding documentation for the Linux driver for the SiFive
PRCI clock & reset control IP block, as found on the SiFive
FU540 chip.

Cc: Michael Turquette <mturquette@baylibre.com>
Cc: Stephen Boyd <sboyd@kernel.org>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Palmer Dabbelt <palmer@sifive.com>
Cc: Megan Wachs <megan@sifive.com>                                                                                                                    Cc: linux-clk@vger.kernel.org
Cc: devicetree@vger.kernel.org
Cc: linux-riscv@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Paul Walmsley <paul.walmsley@sifive.com>
Signed-off-by: Paul Walmsley <paul@pwsan.com>
---
 .../bindings/clock/sifive/fu540-prci.txt      | 40 +++++++++++++++++++
 1 file changed, 40 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/clock/sifive/fu540-prci.txt

diff --git a/Documentation/devicetree/bindings/clock/sifive/fu540-prci.txt b/Documentation/devicetree/bindings/clock/sifive/fu540-prci.txt
new file mode 100644
index 000000000000..27d8fdd4f3a2
--- /dev/null
+++ b/Documentation/devicetree/bindings/clock/sifive/fu540-prci.txt
@@ -0,0 +1,40 @@
+SiFive FU540 PRCI bindings
+
+On the FU540 family of SoCs, most system-wide clock and reset integration
+is via the PRCI IP block.
+
+Required properties:
+- compatible: Should be "sifive,fu540-c000-prci0"
+- reg: Should describe the PRCI's register target physical address region
+- clocks: Should point to the hfclk device tree node and the rtcclk
+          device tree node.  The RTC clock here is not a time-of-day clock,
+	  but is instead a high-stability clock source for system timers
+	  and cycle counters.
+- #clock-cells: Should be <1>
+
+The clock consumer should specify the desired clock via the clock ID
+macros defined in include/linux/clk/sifive-fu540-prci.h.  These macros
+begin with PRCI_CLK_.
+
+
+
+Examples:
+
+hfclk: hfclk {
+	#clock-cells = <0>;
+	compatible = "fixed-clock";
+	clock-frequency = <33333333>;
+	clock-output-names = "hfclk";
+};
+rtcclk: rtcclk {
+	#clock-cells = <0>;
+	compatible = "fixed-clock";
+	clock-frequency = <1000000>;
+	clock-output-names = "rtcclk";
+};
+prci0: prci@10000000 {
+	compatible = "sifive,fu540-c000-prci0", "sifive,prci0";
+	reg = <0x0 0x10000000 0x0 0x1000>;
+	clocks = <&hfclk>, <&rtcclk>;
+	#clock-cells = <1>;
+};
-- 
2.19.1

[PATCH 3/3] clk: sifive: add a driver for the SiFive FU540 PRCI IP block

[Paul Walmsley]

Add driver code for the SiFive FU540 PRCI IP block.  This IP block
handles reset and clock control for the SiFive FU540 device and
implements SoC-level clock tree controls and dividers.

Based on code written by Wesley Terpstra <wesley@sifive.com>:
https://github.com/riscv/riscv-linux/commit/999529edf517ed75b56659d456d221b2ee56bb60

Boot and PLL rate change were tested on a SiFive HiFive Unleashed
board.

Cc: Michael Turquette <mturquette@baylibre.com>
Cc: Stephen Boyd <sboyd@kernel.org>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Wesley W. Terpstra <wesley@sifive.com>
Cc: Palmer Dabbelt <palmer@sifive.com>
Cc: Megan Wachs <megan@sifive.com>
Cc: linux-riscv@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-clk@vger.kernel.org
Signed-off-by: Paul Walmsley <paul.walmsley@sifive.com>
Signed-off-by: Paul Walmsley <paul@pwsan.com>
---
 drivers/clk/Kconfig                   |   1 +
 drivers/clk/Makefile                  |   1 +
 drivers/clk/sifive/Kconfig            |  18 +
 drivers/clk/sifive/Makefile           |   1 +
 drivers/clk/sifive/fu540-prci.c       | 634 ++++++++++++++++++++++++++
 include/linux/clk/sifive-fu540-prci.h |  27 ++
 6 files changed, 682 insertions(+)
 create mode 100644 drivers/clk/sifive/Kconfig
 create mode 100644 drivers/clk/sifive/Makefile
 create mode 100644 drivers/clk/sifive/fu540-prci.c
 create mode 100644 include/linux/clk/sifive-fu540-prci.h

diff --git a/drivers/clk/Kconfig b/drivers/clk/Kconfig
index a34ccfcb54ac..0af5f6843a2f 100644
--- a/drivers/clk/Kconfig
+++ b/drivers/clk/Kconfig
@@ -295,6 +295,7 @@ source "drivers/clk/mvebu/Kconfig"
 source "drivers/clk/qcom/Kconfig"
 source "drivers/clk/renesas/Kconfig"
 source "drivers/clk/samsung/Kconfig"
+source "drivers/clk/sifive/Kconfig"
 source "drivers/clk/sprd/Kconfig"
 source "drivers/clk/sunxi-ng/Kconfig"
 source "drivers/clk/tegra/Kconfig"
diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile
index d59c11ddfc5e..8b07ebab37f8 100644
--- a/drivers/clk/Makefile
+++ b/drivers/clk/Makefile
@@ -91,6 +91,7 @@ obj-$(CONFIG_COMMON_CLK_QCOM)		+= qcom/
 obj-y					+= renesas/
 obj-$(CONFIG_ARCH_ROCKCHIP)		+= rockchip/
 obj-$(CONFIG_COMMON_CLK_SAMSUNG)	+= samsung/
+obj-y					+= sifive/
 obj-$(CONFIG_ARCH_SIRF)			+= sirf/
 obj-$(CONFIG_ARCH_SOCFPGA)		+= socfpga/
 obj-$(CONFIG_PLAT_SPEAR)		+= spear/
diff --git a/drivers/clk/sifive/Kconfig b/drivers/clk/sifive/Kconfig
new file mode 100644
index 000000000000..8db4a3eb4782
--- /dev/null
+++ b/drivers/clk/sifive/Kconfig
@@ -0,0 +1,18 @@
+# SPDX-License-Identifier: GPL-2.0
+
+menuconfig CLK_SIFIVE
+	bool "SiFive SoC driver support"
+	help
+	  SoC drivers for SiFive Linux-capable SoCs.
+
+if CLK_SIFIVE
+
+config CLK_SIFIVE_FU540_PRCI
+	bool "PRCI driver for SiFive FU540 SoCs"
+	select CLK_ANALOGBITS_WRPLL_CLN28HPC
+	help
+	  Supports the Power Reset Clock interface (PRCI) IP block found in
+	  FU540 SoCs.  If this kernel is meant to run on a SiFive FU540 SoC,
+	  enable this driver.
+
+endif
diff --git a/drivers/clk/sifive/Makefile b/drivers/clk/sifive/Makefile
new file mode 100644
index 000000000000..74d58a4c0756
--- /dev/null
+++ b/drivers/clk/sifive/Makefile
@@ -0,0 +1 @@
+obj-$(CONFIG_CLK_SIFIVE_FU540_PRCI)	+= fu540-prci.o
diff --git a/drivers/clk/sifive/fu540-prci.c b/drivers/clk/sifive/fu540-prci.c
new file mode 100644
index 000000000000..870cb8333648
--- /dev/null
+++ b/drivers/clk/sifive/fu540-prci.c
@@ -0,0 +1,634 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * 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.
+ *
+ * The FU540 PRCI implements clock and reset control for the SiFive
+ * FU540-C000 chip.   This driver assumes that it has sole control
+ * over all PRCI resources.
+ *
+ * This driver is based on the PRCI driver written by Wesley Terpstra:
+ * https://github.com/riscv/riscv-linux/commit/999529edf517ed75b56659d456d221b2ee56bb60
+ *
+ * References:
+ * - SiFive FU540-C000 manual v1p0, Chapter 7 "Clocking and Reset"
+ */
+
+#include <linux/clkdev.h>
+#include <linux/clk-provider.h>
+#include <linux/clk.h>
+#include <linux/clk/analogbits-wrpll-cln28hpc.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/log2.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/clk/sifive-fu540-prci.h>
+
+/*
+ * EXPECTED_CLK_PARENT_COUNT: how many parent clocks this driver expects:
+ *     hfclk and rtcclk
+ */
+#define EXPECTED_CLK_PARENT_COUNT		2
+
+/*
+ * Register offsets and bitmasks
+ */
+
+/* COREPLLCFG0 */
+#define PRCI_COREPLLCFG0_OFFSET			0x4
+# define PRCI_COREPLLCFG0_DIVR_SHIFT		0
+# define PRCI_COREPLLCFG0_DIVR_MASK		(0x3f << PRCI_COREPLLCFG0_DIVR_SHIFT)
+# define PRCI_COREPLLCFG0_DIVF_SHIFT		6
+# define PRCI_COREPLLCFG0_DIVF_MASK		(0x1ff << PRCI_COREPLLCFG0_DIVF_SHIFT)
+# define PRCI_COREPLLCFG0_DIVQ_SHIFT		15
+# define PRCI_COREPLLCFG0_DIVQ_MASK		(0x7 << PRCI_COREPLLCFG0_DIVQ_SHIFT)
+# define PRCI_COREPLLCFG0_RANGE_SHIFT		18
+# define PRCI_COREPLLCFG0_RANGE_MASK		(0x7 << PRCI_COREPLLCFG0_RANGE_SHIFT)
+# define PRCI_COREPLLCFG0_BYPASS_SHIFT		24
+# define PRCI_COREPLLCFG0_BYPASS_MASK		(0x1 << PRCI_COREPLLCFG0_BYPASS_SHIFT)
+# define PRCI_COREPLLCFG0_FSE_SHIFT		25
+# define PRCI_COREPLLCFG0_FSE_MASK		(0x1 << PRCI_COREPLLCFG0_FSE_SHIFT)
+# define PRCI_COREPLLCFG0_LOCK_SHIFT		31
+# define PRCI_COREPLLCFG0_LOCK_MASK		(0x1 << PRCI_COREPLLCFG0_LOCK_SHIFT)
+
+/* DDRPLLCFG0 */
+#define PRCI_DDRPLLCFG0_OFFSET			0xc
+# define PRCI_DDRPLLCFG0_DIVR_SHIFT		0
+# define PRCI_DDRPLLCFG0_DIVR_MASK		(0x3f << PRCI_DDRPLLCFG0_DIVR_SHIFT)
+# define PRCI_DDRPLLCFG0_DIVF_SHIFT		6
+# define PRCI_DDRPLLCFG0_DIVF_MASK		(0x1ff << PRCI_DDRPLLCFG0_DIVF_SHIFT)
+# define PRCI_DDRPLLCFG0_DIVQ_SHIFT		15
+# define PRCI_DDRPLLCFG0_DIVQ_MASK		(0x7 << PRCI_DDRPLLCFG0_DIVQ_SHIFT)
+# define PRCI_DDRPLLCFG0_RANGE_SHIFT		18
+# define PRCI_DDRPLLCFG0_RANGE_MASK		(0x7 << PRCI_DDRPLLCFG0_RANGE_SHIFT)
+# define PRCI_DDRPLLCFG0_BYPASS_SHIFT		24
+# define PRCI_DDRPLLCFG0_BYPASS_MASK		(0x1 << PRCI_DDRPLLCFG0_BYPASS_SHIFT)
+# define PRCI_DDRPLLCFG0_FSE_SHIFT		25
+# define PRCI_DDRPLLCFG0_FSE_MASK		(0x1 << PRCI_DDRPLLCFG0_FSE_SHIFT)
+# define PRCI_DDRPLLCFG0_LOCK_SHIFT		31
+# define PRCI_DDRPLLCFG0_LOCK_MASK		(0x1 << PRCI_DDRPLLCFG0_LOCK_SHIFT)
+
+/* DDRPLLCFG1 */
+#define PRCI_DDRPLLCFG1_OFFSET			0x10
+# define PRCI_DDRPLLCFG1_CKE_SHIFT		24
+# define PRCI_DDRPLLCFG1_CKE_MASK		(0x1 << PRCI_DDRPLLCFG1_CKE_SHIFT)
+
+/* GEMGXLPLLCFG0 */
+#define PRCI_GEMGXLPLLCFG0_OFFSET		0x1c
+# define PRCI_GEMGXLPLLCFG0_DIVR_SHIFT		0
+# define PRCI_GEMGXLPLLCFG0_DIVR_MASK		(0x3f << PRCI_GEMGXLPLLCFG0_DIVR_SHIFT)
+# define PRCI_GEMGXLPLLCFG0_DIVF_SHIFT		6
+# define PRCI_GEMGXLPLLCFG0_DIVF_MASK		(0x1ff << PRCI_GEMGXLPLLCFG0_DIVF_SHIFT)
+# define PRCI_GEMGXLPLLCFG0_DIVQ_SHIFT		15
+# define PRCI_GEMGXLPLLCFG0_DIVQ_MASK		(0x7 << PRCI_GEMGXLPLLCFG0_DIVQ_SHIFT)
+# define PRCI_GEMGXLPLLCFG0_RANGE_SHIFT		18
+# define PRCI_GEMGXLPLLCFG0_RANGE_MASK		(0x7 << PRCI_GEMGXLPLLCFG0_RANGE_SHIFT)
+# define PRCI_GEMGXLPLLCFG0_BYPASS_SHIFT	24
+# define PRCI_GEMGXLPLLCFG0_BYPASS_MASK		(0x1 << PRCI_GEMGXLPLLCFG0_BYPASS_SHIFT)
+# define PRCI_GEMGXLPLLCFG0_FSE_SHIFT		25
+# define PRCI_GEMGXLPLLCFG0_FSE_MASK		(0x1 << PRCI_GEMGXLPLLCFG0_FSE_SHIFT)
+# define PRCI_GEMGXLPLLCFG0_LOCK_SHIFT		31
+# define PRCI_GEMGXLPLLCFG0_LOCK_MASK		(0x1 << PRCI_GEMGXLPLLCFG0_LOCK_SHIFT)
+
+/* GEMGXLPLLCFG1 */
+#define PRCI_GEMGXLPLLCFG1_OFFSET		0x20
+# define PRCI_GEMGXLPLLCFG1_CKE_SHIFT		24
+# define PRCI_GEMGXLPLLCFG1_CKE_MASK		(0x1 << PRCI_GEMGXLPLLCFG1_CKE_SHIFT)
+
+/* CORECLKSEL */
+#define PRCI_CORECLKSEL_OFFSET			0x24
+# define PRCI_CORECLKSEL_CORECLKSEL_SHIFT	0
+# define PRCI_CORECLKSEL_CORECLKSEL_MASK	(0x1 << PRCI_CORECLKSEL_CORECLKSEL_SHIFT)
+
+/* DEVICESRESETREG */
+#define PRCI_DEVICESRESETREG_OFFSET			0x28
+# define PRCI_DEVICESRESETREG_DDR_CTRL_RST_N_SHIFT	0
+# define PRCI_DEVICESRESETREG_DDR_CTRL_RST_N_MASK	(0x1 << PRCI_DEVICESRESETREG_DDR_CTRL_RST_N_SHIFT)
+# define PRCI_DEVICESRESETREG_DDR_AXI_RST_N_SHIFT	1
+# define PRCI_DEVICESRESETREG_DDR_AXI_RST_N_MASK	(0x1 << PRCI_DEVICESRESETREG_DDR_AXI_RST_N_SHIFT)
+# define PRCI_DEVICESRESETREG_DDR_AHB_RST_N_SHIFT	2
+# define PRCI_DEVICESRESETREG_DDR_AHB_RST_N_MASK	(0x1 << PRCI_DEVICESRESETREG_DDR_AHB_RST_N_SHIFT)
+# define PRCI_DEVICESRESETREG_DDR_PHY_RST_N_SHIFT	3
+# define PRCI_DEVICESRESETREG_DDR_PHY_RST_N_MASK	(0x1 << PRCI_DEVICESRESETREG_DDR_PHY_RST_N_SHIFT)
+# define PRCI_DEVICESRESETREG_GEMGXL_RST_N_SHIFT	5
+# define PRCI_DEVICESRESETREG_GEMGXL_RST_N_MASK		(0x1 << PRCI_DEVICESRESETREG_GEMGXL_RST_N_SHIFT)
+
+/* CLKMUXSTATUSREG */
+#define PRCI_CLKMUXSTATUSREG_OFFSET			0x2c
+# define PRCI_CLKMUXSTATUSREG_TLCLKSEL_STATUS_SHIFT	1
+# define PRCI_CLKMUXSTATUSREG_TLCLKSEL_STATUS_MASK	(0x1 << PRCI_CLKMUXSTATUSREG_TLCLKSEL_STATUS_SHIFT)
+
+/*
+ * Private structures
+ */
+
+/**
+ * struct __prci_data - per-device-instance data
+ * @va: base virtual address of the PRCI IP block
+ * @hw_clks: encapsulates struct clk_hw records
+ *
+ * PRCI per-device instance data
+ */
+struct __prci_data {
+	void __iomem *va;
+	struct clk_hw_onecell_data hw_clks;
+};
+
+/**
+ * struct __prci_wrpll_data - WRPLL configuration and integration data
+ * @c: WRPLL current configuration record
+ * @bypass: fn ptr to code to bypass the WRPLL (if applicable; else NULL)
+ * @no_bypass: fn ptr to code to not bypass the WRPLL (if applicable; else NULL)
+ * @cfg0_offs: WRPLL CFG0 register offset (in bytes) from the PRCI base address
+ *
+ * @bypass and @no_bypass are used for WRPLL instances that contain a separate
+ * external glitchless clock mux downstream from the PLL.  The WRPLL internal
+ * bypass mux is not glitchless.
+ */
+struct __prci_wrpll_data {
+	struct analogbits_wrpll_cfg c;
+	void (*bypass)(struct __prci_data *pd);
+	void (*no_bypass)(struct __prci_data *pd);
+	u8 cfg0_offs;
+};
+
+/**
+ * struct __prci_clock - describes a clock device managed by PRCI
+ * @name: user-readable clock name string - should match the manual
+ * @parent_name: parent name for this clock
+ * @ops: struct clk_ops for the Linux clock framework to use for control
+ * @hw: Linux-private clock data
+ * @pwd: WRPLL-specific data, associated with this clock (if not NULL)
+ * @pd: PRCI-specific data associated with this clock (if not NULL)
+ *
+ * PRCI clock data.  Used by the PRCI driver to register PRCI-provided
+ * clocks to the Linux clock infrastructure.
+ */
+struct __prci_clock {
+	const char *name;
+	const char *parent_name;
+	const struct clk_ops *ops;
+	struct clk_hw hw;
+	struct __prci_wrpll_data *pwd;
+	struct __prci_data *pd;
+};
+
+#define clk_hw_to_prci_clock(pwd) container_of(pwd, struct __prci_clock, hw)
+
+/*
+ * Private functions
+ */
+
+/**
+ * __prci_readl() - read from a PRCI register
+ * @pd: PRCI context
+ * @offs: register offset to read from (in bytes, from PRCI base address)
+ *
+ * Read the register located at offset @offs from the base virtual
+ * address of the PRCI register target described by @pd, and return
+ * the value to the caller.
+ *
+ * Context: Any context.
+ *
+ * Return: the contents of the register described by @pd and @offs.
+ */
+static u32 __prci_readl(struct __prci_data *pd, u32 offs)
+{
+	return readl_relaxed(pd->va + offs);
+}
+
+static void __prci_writel(u32 v, u32 offs, struct __prci_data *pd)
+{
+	return writel_relaxed(v, pd->va + offs);
+}
+
+/* WRPLL-related private functions */
+
+/**
+ * __prci_wrpll_unpack() - unpack WRPLL configuration registers into parameters
+ * @c: ptr to a struct analogbits_wrpll_cfg record to write config into
+ * @r: value read from the PRCI PLL configuration register
+ *
+ * Given a value @r read from an FU540 PRCI PLL configuration register,
+ * split it into fields and populate it into the WRPLL configuration record
+ * pointed to by @c.
+ *
+ * The COREPLLCFG0 macros are used below, but the other *PLLCFG0 macros
+ * have the same register layout.
+ *
+ * Context: Any context.
+ */
+static void __prci_wrpll_unpack(struct analogbits_wrpll_cfg *c, u32 r)
+{
+	u32 v;
+
+	v = r & PRCI_COREPLLCFG0_DIVR_MASK;
+	v >>= PRCI_COREPLLCFG0_DIVR_SHIFT;
+	c->divr = v;
+
+	v = r & PRCI_COREPLLCFG0_DIVF_MASK;
+	v >>= PRCI_COREPLLCFG0_DIVF_SHIFT;
+	c->divf = v;
+
+	v = r & PRCI_COREPLLCFG0_DIVQ_MASK;
+	v >>= PRCI_COREPLLCFG0_DIVQ_SHIFT;
+	c->divq = v;
+
+	v = r & PRCI_COREPLLCFG0_RANGE_MASK;
+	v >>= PRCI_COREPLLCFG0_RANGE_SHIFT;
+	c->range = v;
+
+	c->flags &= (WRPLL_FLAGS_INT_FEEDBACK_MASK |
+		     WRPLL_FLAGS_EXT_FEEDBACK_MASK);
+
+	if (r & PRCI_COREPLLCFG0_FSE_MASK)
+		c->flags |= WRPLL_FLAGS_INT_FEEDBACK_MASK;
+	else
+		c->flags |= WRPLL_FLAGS_EXT_FEEDBACK_MASK;
+}
+
+/**
+ * __prci_wrpll_pack() - pack PLL configuration parameters into a register value
+ * @c: pointer to a struct analogbits_wrpll_cfg record containing the PLL's cfg
+ *
+ * Using a set of WRPLL configuration values pointed to by @c,
+ * assemble a PRCI PLL configuration register value, and return it to
+ * the caller.
+ *
+ * Context: Any context.  Caller must ensure that the contents of the
+ *          record pointed to by @c do not change during the execution
+ *          of this function.
+ *
+ * Returns: a value suitable for writing into a PRCI PLL configuration
+ *          register
+ */
+static u32 __prci_wrpll_pack(struct analogbits_wrpll_cfg *c)
+{
+	u32 r = 0;
+
+	r |= c->divr << PRCI_COREPLLCFG0_DIVR_SHIFT;
+	r |= c->divf << PRCI_COREPLLCFG0_DIVF_SHIFT;
+	r |= c->divq << PRCI_COREPLLCFG0_DIVQ_SHIFT;
+	r |= c->range << PRCI_COREPLLCFG0_RANGE_SHIFT;
+	if (c->flags & WRPLL_FLAGS_INT_FEEDBACK_MASK)
+		r |= PRCI_COREPLLCFG0_FSE_MASK;
+
+	return r;
+}
+
+/**
+ * __prci_wrpll_read_cfg() - read the WRPLL configuration from the PRCI
+ * @pd: PRCI context
+ * @pwd: PRCI WRPLL metadata
+ *
+ * Read the current configuration of the PLL identified by @pwd from
+ * the PRCI identified by @pd, and store it into the local configuration
+ * cache in @pwd.
+ *
+ * Context: Any context.  Caller must prevent the records pointed to by
+ *          @pd and @pwd from changing during execution.
+ */
+static void __prci_wrpll_read_cfg(struct __prci_data *pd,
+				  struct __prci_wrpll_data *pwd)
+{
+	__prci_wrpll_unpack(&pwd->c, __prci_readl(pd, pwd->cfg0_offs));
+}
+
+/**
+ * __prci_wrpll_write_cfg() - write WRPLL configuration into the PRCI
+ * @pd: PRCI context
+ * @pwd: PRCI WRPLL metadata
+ * @c: WRPLL configuration record to write
+ *
+ * Write the WRPLL configuration described by @c into the WRPLL
+ * configuration register identified by @pwd in the PRCI instance
+ * described by @c.  Make a cached copy of the WRPLL's current
+ * configuration so it can be used by other code.
+ *
+ * Context: Any context.  Caller must prevent the records pointed to by
+ *          @pd and @pwd from changing during execution.
+ */
+static void __prci_wrpll_write_cfg(struct __prci_data *pd,
+				   struct __prci_wrpll_data *pwd,
+				   struct analogbits_wrpll_cfg *c)
+{
+	__prci_writel(__prci_wrpll_pack(c), pwd->cfg0_offs, pd);
+
+	memcpy(&pwd->c, c, sizeof(struct analogbits_wrpll_cfg));
+}
+
+/* Core clock mux control */
+
+/**
+ * __prci_coreclksel_use_hfclk() - switch the CORECLK mux to output HFCLK
+ * @pd: struct __prci_data * for the PRCI containing the CORECLK mux reg
+ *
+ * Switch the CORECLK mux to the HFCLK input source; return once complete.
+ *
+ * Context: Any context.  Caller must prevent concurrent changes to the
+ *          PRCI_CORECLKSEL_OFFSET register.
+ */
+static void __prci_coreclksel_use_hfclk(struct __prci_data *pd)
+{
+	u32 r;
+
+	r = __prci_readl(pd, PRCI_CORECLKSEL_OFFSET);
+	r |= PRCI_CORECLKSEL_CORECLKSEL_MASK;
+	__prci_writel(r, PRCI_CORECLKSEL_OFFSET, pd);
+
+	r = __prci_readl(pd, PRCI_CORECLKSEL_OFFSET); /* barrier */
+}
+
+/**
+ * __prci_coreclksel_use_corepll() - switch the CORECLK mux to output COREPLL
+ * @pd: struct __prci_data * for the PRCI containing the CORECLK mux reg
+ *
+ * Switch the CORECLK mux to the PLL output clock; return once complete.
+ *
+ * Context: Any context.  Caller must prevent concurrent changes to the
+ *          PRCI_CORECLKSEL_OFFSET register.
+ */
+static void __prci_coreclksel_use_corepll(struct __prci_data *pd)
+{
+	u32 r;
+
+	r = __prci_readl(pd, PRCI_CORECLKSEL_OFFSET);
+	r &= ~PRCI_CORECLKSEL_CORECLKSEL_MASK;
+	__prci_writel(r, PRCI_CORECLKSEL_OFFSET, pd);
+
+	r = __prci_readl(pd, PRCI_CORECLKSEL_OFFSET); /* barrier */
+}
+
+/*
+ * Linux clock framework integration
+ *
+ * See the Linux clock framework documentation for more information on
+ * these functions.
+ */
+
+static unsigned long sifive_fu540_prci_wrpll_recalc_rate(struct clk_hw *hw,
+							 unsigned long parent_rate)
+{
+	struct __prci_clock *pc = clk_hw_to_prci_clock(hw);
+	struct __prci_wrpll_data *pwd = pc->pwd;
+
+	return analogbits_wrpll_calc_output_rate(&pwd->c, parent_rate);
+}
+
+static long sifive_fu540_prci_wrpll_round_rate(struct clk_hw *hw,
+					       unsigned long rate,
+					       unsigned long *parent_rate)
+{
+	struct __prci_clock *pc = clk_hw_to_prci_clock(hw);
+	struct __prci_wrpll_data *pwd = pc->pwd;
+	struct analogbits_wrpll_cfg c;
+
+	memcpy(&c, &pwd->c, sizeof(c));
+
+	analogbits_wrpll_configure_for_rate(&c, rate, *parent_rate);
+
+	return analogbits_wrpll_calc_output_rate(&c, *parent_rate);
+}
+
+static int sifive_fu540_prci_wrpll_set_rate(struct clk_hw *hw,
+					    unsigned long rate,
+					    unsigned long parent_rate)
+{
+	struct __prci_clock *pc = clk_hw_to_prci_clock(hw);
+	struct __prci_wrpll_data *pwd = pc->pwd;
+	struct __prci_data *pd = pc->pd;
+	int r;
+
+	r = analogbits_wrpll_configure_for_rate(&pwd->c, rate, parent_rate);
+	if (r)
+		return -ERANGE;
+
+	if (pwd->bypass)
+		pwd->bypass(pd);
+
+	__prci_wrpll_write_cfg(pd, pwd, &pwd->c);
+
+	udelay(analogbits_wrpll_calc_max_lock_us(&pwd->c));
+
+	if (pwd->no_bypass)
+		pwd->no_bypass(pd);
+
+	return 0;
+}
+
+static const struct clk_ops sifive_fu540_prci_wrpll_clk_ops = {
+	.set_rate = sifive_fu540_prci_wrpll_set_rate,
+	.round_rate = sifive_fu540_prci_wrpll_round_rate,
+	.recalc_rate = sifive_fu540_prci_wrpll_recalc_rate,
+};
+
+static const struct clk_ops sifive_fu540_prci_wrpll_ro_clk_ops = {
+	.recalc_rate = sifive_fu540_prci_wrpll_recalc_rate,
+};
+
+/* TLCLKSEL clock integration */
+
+static unsigned long sifive_fu540_prci_tlclksel_recalc_rate(struct clk_hw *hw,
+							    unsigned long parent_rate)
+{
+	struct __prci_clock *pc = clk_hw_to_prci_clock(hw);
+	struct __prci_data *pd = pc->pd;
+	u32 v;
+	u8 div;
+
+	v = __prci_readl(pd, PRCI_CLKMUXSTATUSREG_OFFSET);
+	v &= PRCI_CLKMUXSTATUSREG_TLCLKSEL_STATUS_MASK;
+	div = v ? 1 : 2;
+
+	return div_u64(parent_rate, div);
+}
+
+static const struct clk_ops sifive_fu540_prci_tlclksel_clk_ops = {
+	.recalc_rate = sifive_fu540_prci_tlclksel_recalc_rate,
+};
+
+/*
+ * PRCI integration data for each WRPLL instance
+ */
+
+static struct __prci_wrpll_data __prci_corepll_data = {
+	.cfg0_offs = PRCI_COREPLLCFG0_OFFSET,
+	.bypass = __prci_coreclksel_use_hfclk,
+	.no_bypass = __prci_coreclksel_use_corepll,
+};
+
+static struct __prci_wrpll_data __prci_ddrpll_data = {
+	.cfg0_offs = PRCI_DDRPLLCFG0_OFFSET,
+};
+
+static struct __prci_wrpll_data __prci_gemgxlpll_data = {
+	.cfg0_offs = PRCI_GEMGXLPLLCFG0_OFFSET,
+};
+
+/*
+ * List of clock controls provided by the PRCI
+ */
+
+static struct __prci_clock __prci_init_clocks[] = {
+	[PRCI_CLK_COREPLL] = {
+		.name = "corepll",
+		.parent_name = "hfclk",
+		.ops = &sifive_fu540_prci_wrpll_clk_ops,
+		.pwd = &__prci_corepll_data,
+	},
+	[PRCI_CLK_DDRPLL] = {
+		.name = "ddrpll",
+		.parent_name = "hfclk",
+		.ops = &sifive_fu540_prci_wrpll_ro_clk_ops,
+		.pwd = &__prci_ddrpll_data,
+	},
+	[PRCI_CLK_GEMGXLPLL] = {
+		.name = "gemgxlpll",
+		.parent_name = "hfclk",
+		.ops = &sifive_fu540_prci_wrpll_clk_ops,
+		.pwd = &__prci_gemgxlpll_data,
+	},
+	[PRCI_CLK_TLCLK] = {
+		.name = "tlclk",
+		.parent_name = "corepll",
+		.ops = &sifive_fu540_prci_tlclksel_clk_ops,
+	},
+};
+
+/**
+ * __prci_register_clocks() - register clock controls in the PRCI with Linux
+ * @dev: Linux struct device *
+ *
+ * Register the list of clock controls described in __prci_init_plls[] with
+ * the Linux clock framework.
+ *
+ * Return: 0 upon success or a negative Linux error code upon failure.
+ */
+static int __prci_register_clocks(struct device *dev)
+{
+	struct __prci_data *pd = dev_get_drvdata(dev);
+	struct clk_init_data init;
+	struct __prci_clock *pic;
+	int parent_count, i, clk_hw_count, r;
+
+	parent_count = of_clk_get_parent_count(dev->of_node);
+	if (parent_count != EXPECTED_CLK_PARENT_COUNT) {
+		dev_err(dev, "expected two parent clocks, only found %d\n",
+			parent_count);
+		return -EINVAL;
+	}
+
+	memset(&init, 0, sizeof(struct clk_init_data));
+
+	/* Register PLLs */
+	clk_hw_count = sizeof(__prci_init_clocks) / sizeof(struct __prci_clock);
+
+	for (i = 0; i < clk_hw_count; ++i) {
+		pic = &__prci_init_clocks[i];
+
+		init.name = pic->name;
+		init.parent_names = (const char *[]) { pic->parent_name };
+		init.num_parents = 1;
+		init.ops = pic->ops;
+		init.flags = CLK_IGNORE_UNUSED;
+		pic->hw.init = &init;
+
+		pic->pd = pd;
+
+		if (pic->pwd)
+			__prci_wrpll_read_cfg(pd, pic->pwd);
+
+		r = devm_clk_hw_register(dev, &pic->hw);
+		if (r) {
+			dev_warn(dev, "Failed to register clock %s: %d\n",
+				 init.name, r);
+			return r;
+		}
+
+		r = clk_hw_register_clkdev(&pic->hw, pic->name, dev_name(dev));
+		if (r) {
+			dev_warn(dev, "Failed to register clkdev for %s: %d\n",
+				 init.name, r);
+			return r;
+		}
+
+		pd->hw_clks.hws[i] = &pic->hw;
+	}
+
+	pd->hw_clks.num = i;
+
+	r = devm_of_clk_add_hw_provider(dev, of_clk_hw_onecell_get,
+					&pd->hw_clks);
+	if (r) {
+		dev_err(dev, "could not add hw_provider: %d\n", r);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+/*
+ * Linux device model integration
+ *
+ * See the Linux device model documentation for more information about
+ * these functions.
+ */
+static int sifive_fu540_prci_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct resource *res;
+	struct __prci_data *pd;
+	int r;
+
+	pd = devm_kzalloc(dev, sizeof(struct __prci_data), GFP_KERNEL);
+	if (!pd)
+		return -ENOMEM;
+
+	dev_set_drvdata(dev, pd);
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	pd->va = devm_ioremap_resource(dev, res);
+	if (IS_ERR(pd->va))
+		return PTR_ERR(pd->va);
+
+	r = __prci_register_clocks(dev);
+	if (r) {
+		dev_err(dev, "could not register clocks: %d\n", r);
+		return -EINVAL;
+	}
+
+	dev_info(dev, "SiFive FU540 PRCI probed\n");
+
+	return 0;
+}
+
+static const struct of_device_id sifive_fu540_prci_of_match[] = {
+	{ .compatible = "sifive,fu540-c000-prci0", },
+	{}
+};
+
+static struct platform_driver sifive_fu540_prci_driver = {
+	.driver	= {
+		.name = "sifive-fu540-prci",
+		.of_match_table = sifive_fu540_prci_of_match,
+	},
+	.probe = sifive_fu540_prci_probe,
+};
+
+static int __init sifive_fu540_prci_init(void)
+{
+	return platform_driver_register(&sifive_fu540_prci_driver);
+}
+core_initcall(sifive_fu540_prci_init);
diff --git a/include/linux/clk/sifive-fu540-prci.h b/include/linux/clk/sifive-fu540-prci.h
new file mode 100644
index 000000000000..5d03eae7d4ef
--- /dev/null
+++ b/include/linux/clk/sifive-fu540-prci.h
@@ -0,0 +1,27 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * 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_SIFIVE_FU540_PRCI_H
+#define __LINUX_CLK_SIFIVE_FU540_PRCI_H
+
+/* Clock indexes for use by Device Tree data */
+
+#define PRCI_CLK_COREPLL		0
+#define PRCI_CLK_DDRPLL			1
+#define PRCI_CLK_GEMGXLPLL		2
+#define PRCI_CLK_TLCLK			3
+
+#endif
-- 
2.19.1