[PATCH v2 10/11] riscv: Add K210 pll support

[Sean Anderson <seanga2@gmail.com>]

This pll code is primarily based on the code from the kendryte standalone sdk in
lib/drivers/sysctl.c. k210_pll_calc_params is roughly analogous to the algorithm
used to set the pll frequency, but it has been completely rewritten to be
fixed-point based.

Signed-off-by: Sean Anderson <seanga2@gmail.com>
---
Changes for v2.
  Rename driver to "k210_clk_pll"
  Add additional in-line documentation on algorithm and PLLs.
  Restrict the range of internal VCO and reference frequencies.
  Don't load driver before relocation.
  Remove spurious references to mach-k210.

 board/sipeed/maix/Kconfig          |   1 +
 configs/sipeed_maix_bitm_defconfig |   1 +
 drivers/clk/Kconfig                |   1 +
 drivers/clk/Makefile               |   1 +
 drivers/clk/kendryte/Kconfig       |   7 +
 drivers/clk/kendryte/Makefile      |   1 +
 drivers/clk/kendryte/pll.c         | 598 +++++++++++++++++++++++++++++
 drivers/clk/kendryte/pll.h         |  38 ++
 8 files changed, 648 insertions(+)
 create mode 100644 drivers/clk/kendryte/Kconfig
 create mode 100644 drivers/clk/kendryte/Makefile
 create mode 100644 drivers/clk/kendryte/pll.c
 create mode 100644 drivers/clk/kendryte/pll.h

diff --git a/board/sipeed/maix/Kconfig b/board/sipeed/maix/Kconfig
index 9ffd3aa7aa..10e492a425 100644
--- a/board/sipeed/maix/Kconfig
+++ b/board/sipeed/maix/Kconfig
@@ -37,6 +37,7 @@ config BOARD_SPECIFIC_OPTIONS
 	select SYS_RISCV_NOCOUNTER
 	imply SIFIVE_CLINT
 	imply K210_SYSCTL
+	imply CLK_K210
 	imply SPI
 	imply DM_GPIO
 	imply CMD_GPIO
diff --git a/configs/sipeed_maix_bitm_defconfig b/configs/sipeed_maix_bitm_defconfig
index ecd69c0873..aeab7db0c3 100644
--- a/configs/sipeed_maix_bitm_defconfig
+++ b/configs/sipeed_maix_bitm_defconfig
@@ -65,6 +65,7 @@ CONFIG_OF_TRANSLATE=y
 CONFIG_CLK=y
 CONFIG_CLK_CCF=y
 CONFIG_CLK_COMPOSITE_CCF=y
+CONFIG_CLK_K210=y
 CONFIG_CPU=y
 CONFIG_CPU_RISCV=y
 CONFIG_MMC=y
diff --git a/drivers/clk/Kconfig b/drivers/clk/Kconfig
index 16d4237f89..af75c7c4cf 100644
--- a/drivers/clk/Kconfig
+++ b/drivers/clk/Kconfig
@@ -145,6 +145,7 @@ source "drivers/clk/analogbits/Kconfig"
 source "drivers/clk/at91/Kconfig"
 source "drivers/clk/exynos/Kconfig"
 source "drivers/clk/imx/Kconfig"
+source "drivers/clk/kendryte/Kconfig"
 source "drivers/clk/meson/Kconfig"
 source "drivers/clk/mvebu/Kconfig"
 source "drivers/clk/owl/Kconfig"
diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile
index 06131edb9f..4f3893f6fc 100644
--- a/drivers/clk/Makefile
+++ b/drivers/clk/Makefile
@@ -26,6 +26,7 @@ obj-$(CONFIG_CLK_BCM6345) += clk_bcm6345.o
 obj-$(CONFIG_CLK_BOSTON) += clk_boston.o
 obj-$(CONFIG_CLK_EXYNOS) += exynos/
 obj-$(CONFIG_CLK_HSDK) += clk-hsdk-cgu.o
+obj-$(CONFIG_CLK_K210) += kendryte/
 obj-$(CONFIG_CLK_MPC83XX) += mpc83xx_clk.o
 obj-$(CONFIG_CLK_OWL) += owl/
 obj-$(CONFIG_CLK_RENESAS) += renesas/
diff --git a/drivers/clk/kendryte/Kconfig b/drivers/clk/kendryte/Kconfig
new file mode 100644
index 0000000000..a178d50f5e
--- /dev/null
+++ b/drivers/clk/kendryte/Kconfig
@@ -0,0 +1,7 @@
+config CLK_K210
+	bool "Clock support for Kendryte K210"
+	depends on K210_SYSCTL
+	select CLK
+	select CLK_CCF
+	help
+	  This enables support clock driver for Kendryte K210 platforms.
diff --git a/drivers/clk/kendryte/Makefile b/drivers/clk/kendryte/Makefile
new file mode 100644
index 0000000000..c56d93ea1c
--- /dev/null
+++ b/drivers/clk/kendryte/Makefile
@@ -0,0 +1 @@
+obj-y += pll.o
diff --git a/drivers/clk/kendryte/pll.c b/drivers/clk/kendryte/pll.c
new file mode 100644
index 0000000000..cbb112f5a8
--- /dev/null
+++ b/drivers/clk/kendryte/pll.c
@@ -0,0 +1,598 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2019 Sean Anderson <seanga2@gmail.com>
+ */
+#include "pll.h"
+
+#define LOG_CATEGORY UCLASS_CLK
+#include <asm/io.h>
+/* For DIV_ROUND_DOWN_ULL, defined in linux/kernel.h */
+#include <div64.h>
+#include <dt-bindings/clock/k210-sysctl.h>
+#include <linux/bitfield.h>
+#include <linux/clk-provider.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <log.h>
+
+#define CLK_K210_PLL "k210_clk_pll"
+#define to_k210_pll(_clk) container_of(_clk, struct k210_pll, clk)
+
+static int k210_pll_enable(struct clk *clk);
+static int k210_pll_disable(struct clk *clk);
+
+/*
+ * The logical layout of the PLL is approximately the following:
+ *
+ *    +-----------+
+ *    |input clock|
+ *    +-----------+
+ *          |
+ *          v
+ *        +--+
+ *        |/r|
+ *        +--+
+ *          |
+ *          v
+ *  +---------------+
+ *  |reference clock|
+ *  +---------------+
+ *          |
+ *          v
+ * +----------------+
+ * |phase comparator|<--+
+ * +----------------+   |
+ *          |           |
+ *          v           |
+ *        +---+         |
+ *        |VCO|         |
+ *        +---+         |
+ *          |    +--+   |
+ *          +--->|/f|---+
+ *          |    +--+
+ *          v
+ *        +---+
+ *        |/od|
+ *        +---+
+ *          |
+ *          v
+ *       +------+
+ *       |output|
+ *       +------+
+ *
+ * The k210 PLLs have three factors: r, f, and od. Because of the feedback mode,
+ * the effect of the division by f is to multiply the input frequency. The
+ * equation for the output rate is
+ * 	rate = (rate_in * f) / (r * od).
+ * Moving knowns to one side of the equation, we get
+ *	rate / rate_in = f / (r * od)
+ * Rearranging slightly,
+ *	abs_error = abs((rate / rate_in) - (f / (r * od))).
+ * To get relative, error, we divide by the expected ratio
+ *	error = abs((rate / rate_in) - (f / (r * od))) / (rate / rate_in).
+ * Simplifying,
+ *	error = abs(1 - f / (r * od)) / (rate / rate_in)
+ *	error = abs(1 - (f * rate_in) / (r * od * rate))
+ * Using the constants ratio = rate / rate_in and inv_ratio = rate_in / rate,
+ *	error = abs((f * inv_ratio) / (r * od) - 1)
+ * This is the error used in evaluating parameters.
+ *
+ * r and od are four bits each, while f is six bits. Because r and od are
+ * multiplied together, instead of the full 256 values possible if both bits
+ * were used fully, there are only 97 distinct products. Combined with f, there
+ * are 6208 theoretical settings for the PLL. However, most of these settings
+ * can be ruled out immediately because they do not have the correct ratio.
+ *
+ * In addition to the constraint of approximating the desired ratio, parameters
+ * must also keep internal pll frequencies within acceptable ranges. The
+ * reference clock's minimum and maximum frequencies have a ratio of around 128.
+ * This leaves fairly substantial room work work with, especially since the only
+ * affected parameter is r. The VCO's minimum and maximum frequency have a ratio
+ * of 5, which is considerably more restrictive.
+ *
+ * The r and od factors are stored in a table. This is to make it easy to find
+ * the next-largest product. Some products have multiple factorizations, but
+ * only when one factor has at least a 2.5x ratio to the factors of the other
+ * factorization. This is because any smaller ratio would not make a difference
+ * when ensuring the VCO's frequency is within spec.
+ *
+ * Throughout the calculation function, fixed point arithmetic is used. Because
+ * the range of rate and rate_in may be up to 1.75 GHz, or around 2^30, 64-bit
+ * 32.32 fixed-point numbers are used to represent ratios. In general, to
+ * implement division, the numerator is first multiplied by 2^32. This gives a
+ * result where the whole number part is in the upper 32 bits, and the fraction
+ * is in the lower 32 bits.
+ *
+ * In general, rounding is done to the closest integer. This helps find the best
+ * approximation for the ratio. Rounding in one direction (e.g down) could cause
+ * the function to miss a better ratio with one of the parameters increased by
+ * one.
+ */
+
+/*
+ * The factors table was generated with the following python code:
+ *
+ * def p(x, y):
+ *    return (1.0*x/y > 2.5) or (1.0*y/x > 2.5)
+ *
+ * factors = {}
+ * for i in range(1, 17):
+ *    for j in range(1, 17):
+ *       fs = factors.get(i*j) or []
+ *       if fs == [] or all([
+ *             (p(i, x) and p(i, y)) or (p(j, x) and p(j, y))
+ *             for (x, y) in fs]):
+ *          fs.append((i, j))
+ *          factors[i*j] = fs
+ *
+ * for k, l in sorted(factors.items()):
+ *    for v in l:
+ *       print("PACK(%s, %s)," % v)
+ */
+#define PACK(r, od) ((((r - 1) & 0xF) << 4) | ((od - 1) & 0xF))
+#define UNPACK_R(val) (((val >> 4) & 0xF) + 1)
+#define UNPACK_OD(val) ((val & 0xF) + 1)
+static const u8 factors[] = {
+	PACK(1, 1),
+	PACK(1, 2),
+	PACK(1, 3),
+	PACK(1, 4),
+	PACK(1, 5),
+	PACK(1, 6),
+	PACK(1, 7),
+	PACK(1, 8),
+	PACK(1, 9),
+	PACK(3, 3),
+	PACK(1, 10),
+	PACK(1, 11),
+	PACK(1, 12),
+	PACK(3, 4),
+	PACK(1, 13),
+	PACK(1, 14),
+	PACK(1, 15),
+	PACK(3, 5),
+	PACK(1, 16),
+	PACK(4, 4),
+	PACK(2, 9),
+	PACK(2, 10),
+	PACK(3, 7),
+	PACK(2, 11),
+	PACK(2, 12),
+	PACK(5, 5),
+	PACK(2, 13),
+	PACK(3, 9),
+	PACK(2, 14),
+	PACK(2, 15),
+	PACK(2, 16),
+	PACK(3, 11),
+	PACK(5, 7),
+	PACK(3, 12),
+	PACK(3, 13),
+	PACK(4, 10),
+	PACK(3, 14),
+	PACK(4, 11),
+	PACK(3, 15),
+	PACK(3, 16),
+	PACK(7, 7),
+	PACK(5, 10),
+	PACK(4, 13),
+	PACK(6, 9),
+	PACK(5, 11),
+	PACK(4, 14),
+	PACK(4, 15),
+	PACK(7, 9),
+	PACK(4, 16),
+	PACK(5, 13),
+	PACK(6, 11),
+	PACK(5, 14),
+	PACK(6, 12),
+	PACK(5, 15),
+	PACK(7, 11),
+	PACK(6, 13),
+	PACK(5, 16),
+	PACK(9, 9),
+	PACK(6, 14),
+	PACK(8, 11),
+	PACK(6, 15),
+	PACK(7, 13),
+	PACK(6, 16),
+	PACK(7, 14),
+	PACK(9, 11),
+	PACK(10, 10),
+	PACK(8, 13),
+	PACK(7, 15),
+	PACK(9, 12),
+	PACK(10, 11),
+	PACK(7, 16),
+	PACK(9, 13),
+	PACK(8, 15),
+	PACK(11, 11),
+	PACK(9, 14),
+	PACK(8, 16),
+	PACK(10, 13),
+	PACK(11, 12),
+	PACK(9, 15),
+	PACK(10, 14),
+	PACK(11, 13),
+	PACK(9, 16),
+	PACK(10, 15),
+	PACK(11, 14),
+	PACK(12, 13),
+	PACK(10, 16),
+	PACK(11, 15),
+	PACK(12, 14),
+	PACK(13, 13),
+	PACK(11, 16),
+	PACK(12, 15),
+	PACK(13, 14),
+	PACK(12, 16),
+	PACK(13, 15),
+	PACK(14, 14),
+	PACK(13, 16),
+	PACK(14, 15),
+	PACK(14, 16),
+	PACK(15, 15),
+	PACK(15, 16),
+	PACK(16, 16),
+};
+
+struct k210_pll_params {
+	u8 r;
+	u8 f;
+	u8 od;
+};
+
+static int k210_pll_calc_params(u32 rate, u32 rate_in,
+				struct k210_pll_params *best)
+{
+	int i;
+	s64 error, best_error;
+	u64 ratio, inv_ratio; /* fixed point 32.32 ratio of the rates */
+	u64 max_r;
+	u64 r, f, od;
+
+	/*
+	 * Can't go over 1.75 GHz or under 855 kHz due to limitations on the
+	 * reference clock frequency. These are not the same limits as below
+	 * because od can reduce the output frequency by 16.
+	 */
+	if (rate > 1750000000 || rate < 854493)
+		return -EINVAL;
+
+	ratio = DIV_ROUND_CLOSEST_ULL((u64)rate << 32, rate_in);
+	inv_ratio = DIV_ROUND_CLOSEST_ULL((u64)rate_in << 32, rate);
+	/* Can't increase by more than 64 or reduce by more than 256 */
+	if (rate > rate_in && ratio > (64ULL << 32))
+		return -EINVAL;
+	else if (rate <= rate_in && inv_ratio > (256ULL << 32))
+		return -EINVAL;
+
+	/*
+	 * The reference clock (rate_in / r) must stay between 1.75 GHz and 13
+	 * MHz. There is no minimum, since the only way to get a higher input
+	 * clock than 26 MHz is to use a clock generated by a PLL. Because PLLs
+	 * cannot output frequencies greater than 1.75 GHz, the minimum would
+	 * never be greater than one.
+	 */
+	max_r = DIV_ROUND_DOWN_ULL(rate_in, 13671875);
+
+	/* Variables get immediately incremented, so start at -1th iteration */ 
+	i = -1;
+	f = 0;
+	r = 0;
+	od = 0;
+	error = best_error = S64_MAX;
+	/* do-while here so we always try@least one ratio */
+	do {
+		/*
+		 * Whether we swapped r and od while enforcing frequency limits
+		 */
+		bool swapped = false;
+		u64 last_od = od;
+		u64 last_r = r;
+
+		/*
+		 * Try the next largest value for f (or r and od) and
+		 * recalculate the other parameters based on that
+		 */
+		if (rate > rate_in) {
+			/*
+			 * Skip factors of the same product if we already tried
+			 * out that product
+			 */
+			do {
+				i++;
+				r = UNPACK_R(factors[i]);
+				od = UNPACK_OD(factors[i]);
+			} while (i + 1 < ARRAY_SIZE(factors)
+				 && r * od == last_r * last_od);
+			
+			/* Round close */
+			f = (r * od * ratio + BIT(31)) >> 32;
+			if (f > 64)
+				f = 64;
+		} else {
+			u64 tmp = ++f * inv_ratio;
+			bool round_up = !!(tmp & BIT(31));
+			u32 goal = (tmp >> 32) + round_up;
+			u32 err, last_err;
+
+			/* Get the next r/od pair in factors */
+			while (r * od < goal && i + 1 < ARRAY_SIZE(factors)) {
+				i++;
+				r = UNPACK_R(factors[i]);
+				od = UNPACK_OD(factors[i]);
+			}
+
+			/*
+			 * This is a case of double rounding. If we rounded up
+			 * above, we need to round down (in cases of ties) here.
+			 * This prevents off-by-one errors resulting from
+			 * choosing X+2 over X when X.Y rounds up to X+1 and
+			 * there is no r * od = X+1. For the converse, when X.Y
+			 * is rounded down to X, we should choose X+1 over X-1.
+			 */
+			err = abs(r * od - goal);
+			last_err = abs(last_r * last_od - goal);
+			if (last_err < err || (round_up && (last_err = err))) {
+				i--;
+				r = last_r;
+				od = last_od;
+			}
+		}
+
+		/*
+		 * Enforce limits on internal clock frequencies. If we
+		 * aren't in spec, try swapping r and od. If everything is
+		 * in-spec, calculate the relative error.
+		 */
+		while (true) {
+			/*
+			 * Whether the intermediate frequencies are out-of-spec
+			 */
+			bool out_of_spec = false;
+
+			if (r > max_r) {
+				out_of_spec = true;
+			} else {
+				/*
+				 * There is no way to only divide once; we need
+				 * to examine the frequency with and without the
+				 * effect of od.
+				 */
+				u64 vco = DIV_ROUND_CLOSEST_ULL(rate_in * f, r);
+				if (vco > 1750000000 || vco < 350000000)
+					out_of_spec = true;
+			}
+
+			if (out_of_spec) {
+				if (!swapped) {
+					u64 tmp = r;
+					r = od;
+					od = tmp;
+					swapped = true;
+					continue;
+				} else {
+					/*
+					 * Try looking ahead to see if there are
+					 * additional factors for the same
+					 * product.
+					 */
+					if (i + 1 < ARRAY_SIZE(factors)) {
+						u64 new_r, new_od;
+
+						i++;
+						new_r = UNPACK_R(factors[i]);
+						new_od = UNPACK_OD(factors[i]);
+						if (r * od == new_r * new_od) {
+							r = new_r;
+							od = new_od;
+							swapped = false;
+							continue;
+						}
+						i--;
+					}
+					break;
+				}
+			}
+
+			error = DIV_ROUND_CLOSEST_ULL(f * inv_ratio, r * od);
+			/* The lower 16 bits are spurious */
+			error = abs((error - BIT(32))) >> 16;
+
+			if (error < best_error) {
+				best->r = r;
+				best->f = f;
+				best->od = od;
+				best_error = error;
+			}
+			break;
+		}
+	} while (f < 64 && i + 1 < ARRAY_SIZE(factors) && error != 0);
+
+	if (best_error == S64_MAX)
+		return -EINVAL;
+
+	log_debug("best error %lld\n", best_error);
+	return 0;
+}
+
+static ulong k210_pll_set_rate(struct clk *clk, ulong rate)
+{
+	int err;
+	long long rate_in = clk_get_parent_rate(clk);
+	struct k210_pll_params params = {};
+	struct k210_pll *pll = to_k210_pll(clk);
+	u32 reg;
+	
+	if (rate_in < 0)
+		return rate_in;
+
+	log_debug("Calculating parameters with rate=%lu and rate_in=%lld\n",
+		  rate, rate_in);
+	err = k210_pll_calc_params(rate, rate_in, &params);
+	if (err)
+		return err;
+	log_debug("Got r=%u f=%u od=%u\n", params.r, params.f, params.od);
+
+	/*
+	 * Don't use clk_disable as it might not actually disable the pll due to
+	 * refcounting
+	 */
+	err = k210_pll_disable(clk);
+	if (err)
+		return err;
+
+	reg = readl(pll->reg);
+	reg &= ~K210_PLL_CLKR
+	    & ~K210_PLL_CLKF
+	    & ~K210_PLL_CLKOD
+	    & ~K210_PLL_BWADJ;
+	reg |= FIELD_PREP(K210_PLL_CLKR, params.r - 1)
+	    | FIELD_PREP(K210_PLL_CLKF, params.f - 1)
+	    | FIELD_PREP(K210_PLL_CLKOD, params.od - 1)
+	    | FIELD_PREP(K210_PLL_BWADJ, params.f - 1);
+	writel(reg, pll->reg);
+
+	err = k210_pll_enable(clk);
+	if (err)
+		return err;
+
+	return clk_get_rate(clk);
+}
+
+static ulong k210_pll_get_rate(struct clk *clk)
+{
+
+	long long rate_in = clk_get_parent_rate(clk);
+	struct k210_pll *pll = to_k210_pll(clk);
+	u64 r, f, od;
+	u32 reg = readl(pll->reg);
+
+	if (rate_in < 0)
+		return rate_in;
+
+	if (reg & K210_PLL_BYPASS)
+		return rate_in;
+	
+	r = FIELD_GET(K210_PLL_CLKR, reg) + 1;
+	f = FIELD_GET(K210_PLL_CLKF, reg) + 1;
+	od = FIELD_GET(K210_PLL_CLKOD, reg) + 1;
+
+	return DIV_ROUND_DOWN_ULL(((u64)rate_in) * f, r * od);
+}
+
+/* Check if the PLL is locked */
+static int k210_pll_locked(struct k210_pll *pll)
+{
+	u32 reg = readl(pll->lock);
+
+	return (reg & pll->lock_mask) == pll->lock_mask;
+}
+
+/*
+ * Wait for the PLL to be locked. If the PLL is not locked, try clearing the
+ * slip before retrying
+ */
+static void k210_pll_waitfor_lock(struct k210_pll *pll)
+{
+	while (!k210_pll_locked(pll)) {
+		u32 reg = readl(pll->lock);
+
+		reg |= BIT(pll->shift + K210_PLL_CLEAR_SLIP);
+		writel(reg, pll->lock);
+		udelay(1);
+	}
+}
+
+/* Adapted from sysctl_pll_enable */
+static int k210_pll_enable(struct clk *clk)
+{
+	struct k210_pll *pll = to_k210_pll(clk);
+	u32 reg = readl(pll->reg);
+
+	reg &= ~K210_PLL_BYPASS;
+	writel(reg, pll->reg);
+
+	reg |= K210_PLL_PWRD;
+	writel(reg, pll->reg);
+
+	/* Ensure reset is low before asserting it */
+	reg &= ~K210_PLL_RESET;
+	writel(reg, pll->reg);
+	reg |= K210_PLL_RESET;
+	writel(reg, pll->reg);
+	/* FIXME: this doesn't really have to be a whole microsecond */
+	udelay(1);
+	reg &= ~K210_PLL_RESET;
+	writel(reg, pll->reg);
+
+	k210_pll_waitfor_lock(pll);
+	return 0;
+}
+
+static int k210_pll_disable(struct clk *clk)
+{
+	struct k210_pll *pll = to_k210_pll(clk);
+	u32 reg = readl(pll->reg);
+
+	/*
+	 * Bypassing before powering off is important so child clocks don't stop
+	 * working. This is especially important for pll0, the indirect parent
+	 * of the cpu clock.
+	 */
+	reg |= K210_PLL_BYPASS;
+	writel(reg, pll->reg);
+
+	reg &= ~K210_PLL_PWRD;
+	writel(reg, pll->reg);
+	return 0;
+}
+
+const struct clk_ops k210_pll_ops = {
+	.get_rate = k210_pll_get_rate,
+	.set_rate = k210_pll_set_rate,
+	.enable = k210_pll_enable,
+	.disable = k210_pll_disable,
+};
+
+struct k210_pll *k210_clk_comp_pll(void __iomem *reg, void __iomem *lock,
+				       u8 shift, u8 width)
+{
+	struct k210_pll *pll;
+
+	
+	pll = kzalloc(sizeof(*pll), GFP_KERNEL);
+	if (!pll)
+		return pll;
+	pll->reg = reg;
+	pll->lock = lock;
+	pll->shift = shift;
+	pll->lock_mask = GENMASK(shift + width, shift);
+	return pll;
+}
+
+struct clk *k210_clk_pll(const char *name, const char *parent_name,
+			 void __iomem *reg, void __iomem *lock, u8 shift,
+			 u8 width)
+{
+	int err;
+	struct k210_pll *pll;
+
+	pll = k210_clk_comp_pll(reg, lock, shift, width);
+	if (!pll)
+		return ERR_PTR(-ENOMEM);
+
+	err = clk_register(&pll->clk, CLK_K210_PLL, name, parent_name);
+	if (err) {
+		kfree(pll);
+		return ERR_PTR(err);
+	}
+	return &pll->clk;
+}
+
+U_BOOT_DRIVER(k210_pll) = {
+	.name	= CLK_K210_PLL,
+	.id	= UCLASS_CLK,
+	.ops	= &k210_pll_ops,
+};
diff --git a/drivers/clk/kendryte/pll.h b/drivers/clk/kendryte/pll.h
new file mode 100644
index 0000000000..6a8734a295
--- /dev/null
+++ b/drivers/clk/kendryte/pll.h
@@ -0,0 +1,38 @@
+#ifndef K210_PLL_H
+#define K210_PLL_H
+
+#include <clk.h>
+
+#define K210_PLL_CLKR GENMASK(3, 0)
+#define K210_PLL_CLKF GENMASK(9, 4)
+#define K210_PLL_CLKOD GENMASK(13, 10)
+#define K210_PLL_BWADJ GENMASK(19, 14)
+#define K210_PLL_RESET BIT(20)
+#define K210_PLL_PWRD BIT(21)
+#define K210_PLL_INTFB BIT(22)
+#define K210_PLL_BYPASS BIT(23)
+#define K210_PLL_TEST BIT(24)
+#define K210_PLL_EN BIT(25)
+#define K210_PLL_TEST_EN BIT(26)
+
+#define K210_PLL_LOCK 0
+#define K210_PLL_CLEAR_SLIP 2
+#define K210_PLL_TEST_OUT 3
+
+struct k210_pll {
+	struct clk clk;
+	void __iomem *reg; /* Base PLL register */
+	void __iomem *lock; /* Common PLL lock register */
+	u8 shift; /* Offset of bits in lock register */
+	u8 lock_mask; /* Mask of lock bits to test against, pre-shifted */
+};
+
+extern const struct clk_ops k210_pll_ops;
+
+struct k210_pll *k210_clk_comp_pll(void __iomem *reg, void __iomem *lock,
+				   u8 shift, u8 width);
+struct clk *k210_clk_pll(const char *name, const char *parent_name,
+			 void __iomem *reg, void __iomem *lock, u8 shift,
+			 u8 width);
+
+#endif /* K210_PLL_H */
-- 
2.24.1