clk: add support for TI K3 SoC PLL

Add support for TI K3 SoC PLLs. This clock type supports
enabling/disabling/setting and querying the clock rate for the PLL. The
euclidean library routine is used to calculate divider/multiplier rates
for the PLLs.

Signed-off-by: Tero Kristo <t-kristo@ti.com>
Signed-off-by: Tero Kristo <kristo@kernel.org>

drivers/clk/ti/Kconfig

@@ -41,3 +41,15 @@ config CLK_TI_SCI
 	  This enables the clock driver support over TI System Control Interface
 	  available on some new TI's SoCs. If you wish to use clock resources
 	  managed by the TI System Controller, say Y here. Otherwise, say N.
+
+config CLK_K3_PLL
+	bool "PLL clock support for K3 SoC family of devices"
+	depends on CLK && LIB_RATIONAL
+	help
+	  Enables PLL clock support for K3 SoC family of devices.
+
+config SPL_CLK_K3_PLL
+	bool "PLL clock support for K3 SoC family of devices"
+	depends on CLK && LIB_RATIONAL && SPL
+	help
+	  Enables PLL clock support for K3 SoC family of devices.

drivers/clk/ti/Makefile

@@ -11,3 +11,4 @@ obj-$(CONFIG_CLK_TI_DIVIDER) += clk-divider.o
 obj-$(CONFIG_CLK_TI_GATE) += clk-gate.o
 obj-$(CONFIG_CLK_TI_MUX) += clk-mux.o
 obj-$(CONFIG_CLK_TI_SCI) += clk-sci.o
+obj-$(CONFIG_$(SPL_TPL_)CLK_K3_PLL) += clk-k3-pll.o

drivers/clk/ti/clk-k3-pll.c

@@ -0,0 +1,283 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Texas Instruments K3 SoC PLL clock driver
+ *
+ * Copyright (C) 2020 Texas Instruments Incorporated - http://www.ti.com/
+ *	Tero Kristo <t-kristo@ti.com>
+ */
+
+#include <common.h>
+#include <asm/io.h>
+#include <dm.h>
+#include <div64.h>
+#include <errno.h>
+#include <clk-uclass.h>
+#include <linux/clk-provider.h>
+#include "k3-clk.h"
+#include <linux/rational.h>
+
+/* 16FFT register offsets */
+#define PLL_16FFT_CFG			0x08
+#define PLL_KICK0			0x10
+#define PLL_KICK1			0x14
+#define PLL_16FFT_CTRL			0x20
+#define PLL_16FFT_STAT			0x24
+#define PLL_16FFT_FREQ_CTRL0		0x30
+#define PLL_16FFT_FREQ_CTRL1		0x34
+#define PLL_16FFT_DIV_CTRL		0x38
+
+/* CTRL register bits */
+#define PLL_16FFT_CTRL_BYPASS_EN	BIT(31)
+#define PLL_16FFT_CTRL_PLL_EN		BIT(15)
+#define PLL_16FFT_CTRL_DSM_EN		BIT(1)
+
+/* STAT register bits */
+#define PLL_16FFT_STAT_LOCK		BIT(0)
+
+/* FREQ_CTRL0 bits */
+#define PLL_16FFT_FREQ_CTRL0_FB_DIV_INT_MASK	0xfff
+
+/* DIV CTRL register bits */
+#define PLL_16FFT_DIV_CTRL_REF_DIV_MASK		0x3f
+
+#define PLL_16FFT_FREQ_CTRL1_FB_DIV_FRAC_BITS	24
+#define PLL_16FFT_HSDIV_CTRL_CLKOUT_EN          BIT(15)
+
+/* KICK register magic values */
+#define PLL_KICK0_VALUE				0x68ef3490
+#define PLL_KICK1_VALUE				0xd172bc5a
+
+/**
+ * struct ti_pll_clk - TI PLL clock data info structure
+ * @clk: core clock structure
+ * @reg: memory address of the PLL controller
+ */
+struct ti_pll_clk {
+	struct clk	clk;
+	void __iomem	*reg;
+};
+
+#define to_clk_pll(_clk) container_of(_clk, struct ti_pll_clk, clk)
+
+static int ti_pll_wait_for_lock(struct clk *clk)
+{
+	struct ti_pll_clk *pll = to_clk_pll(clk);
+	u32 stat;
+	int i;
+
+	for (i = 0; i < 100000; i++) {
+		stat = readl(pll->reg + PLL_16FFT_STAT);
+		if (stat & PLL_16FFT_STAT_LOCK)
+			return 0;
+	}
+
+	printf("%s: pll (%s) failed to lock\n", __func__,
+	       clk->dev->name);
+
+	return -EBUSY;
+}
+
+static ulong ti_pll_clk_get_rate(struct clk *clk)
+{
+	struct ti_pll_clk *pll = to_clk_pll(clk);
+	u64 current_freq;
+	u64 parent_freq = clk_get_parent_rate(clk);
+	u32 pllm;
+	u32 plld;
+	u32 pllfm;
+	u32 ctrl;
+
+	/* Check if we are in bypass */
+	ctrl = readl(pll->reg + PLL_16FFT_CTRL);
+	if (ctrl & PLL_16FFT_CTRL_BYPASS_EN)
+		return parent_freq;
+
+	pllm = readl(pll->reg + PLL_16FFT_FREQ_CTRL0);
+	pllfm = readl(pll->reg + PLL_16FFT_FREQ_CTRL1);
+
+	plld = readl(pll->reg + PLL_16FFT_DIV_CTRL) &
+		PLL_16FFT_DIV_CTRL_REF_DIV_MASK;
+
+	current_freq = parent_freq * pllm / plld;
+
+	if (pllfm) {
+		u64 tmp;
+
+		tmp = parent_freq * pllfm;
+		do_div(tmp, plld);
+		tmp >>= PLL_16FFT_FREQ_CTRL1_FB_DIV_FRAC_BITS;
+		current_freq += tmp;
+	}
+
+	return current_freq;
+}
+
+static ulong ti_pll_clk_set_rate(struct clk *clk, ulong rate)
+{
+	struct ti_pll_clk *pll = to_clk_pll(clk);
+	u64 current_freq;
+	u64 parent_freq = clk_get_parent_rate(clk);
+	int ret;
+	u32 ctrl;
+	unsigned long pllm;
+	u32 pllfm = 0;
+	unsigned long plld;
+	u32 rem;
+	int shift;
+
+	debug("%s(clk=%p, rate=%u)\n", __func__, clk, (u32)rate);
+
+	if (ti_pll_clk_get_rate(clk) == rate)
+		return rate;
+
+	if (rate != parent_freq)
+		/*
+		 * Attempt with higher max multiplier value first to give
+		 * some space for fractional divider to kick in.
+		 */
+		for (shift = 8; shift >= 0; shift -= 8) {
+			rational_best_approximation(rate, parent_freq,
+				((PLL_16FFT_FREQ_CTRL0_FB_DIV_INT_MASK + 1) << shift) - 1,
+				PLL_16FFT_DIV_CTRL_REF_DIV_MASK, &pllm, &plld);
+			if (pllm / plld <= PLL_16FFT_FREQ_CTRL0_FB_DIV_INT_MASK)
+				break;
+		}
+
+	/* Put PLL to bypass mode */
+	ctrl = readl(pll->reg + PLL_16FFT_CTRL);
+	ctrl |= PLL_16FFT_CTRL_BYPASS_EN;
+	writel(ctrl, pll->reg + PLL_16FFT_CTRL);
+
+	if (rate == parent_freq) {
+		debug("%s: put %s to bypass\n", __func__, clk->dev->name);
+		return rate;
+	}
+
+	debug("%s: pre-frac-calc: rate=%u, parent_freq=%u, plld=%u, pllm=%u\n",
+	      __func__, (u32)rate, (u32)parent_freq, (u32)plld, (u32)pllm);
+
+	/* Check if we need fractional config */
+	if (plld > 1) {
+		pllfm = pllm % plld;
+		pllfm <<= PLL_16FFT_FREQ_CTRL1_FB_DIV_FRAC_BITS;
+		rem = pllfm % plld;
+		pllfm /= plld;
+		if (rem)
+			pllfm++;
+		pllm /= plld;
+		plld = 1;
+	}
+
+	if (pllfm)
+		ctrl |= PLL_16FFT_CTRL_DSM_EN;
+	else
+		ctrl &= ~PLL_16FFT_CTRL_DSM_EN;
+
+	writel(pllm, pll->reg + PLL_16FFT_FREQ_CTRL0);
+	writel(pllfm, pll->reg + PLL_16FFT_FREQ_CTRL1);
+	writel(plld, pll->reg + PLL_16FFT_DIV_CTRL);
+
+	ctrl &= ~PLL_16FFT_CTRL_BYPASS_EN;
+	ctrl |= PLL_16FFT_CTRL_PLL_EN;
+	writel(ctrl, pll->reg + PLL_16FFT_CTRL);
+
+	ret = ti_pll_wait_for_lock(clk);
+	if (ret)
+		return ret;
+
+	debug("%s: pllm=%u, plld=%u, pllfm=%u, parent_freq=%u\n",
+	      __func__, (u32)pllm, (u32)plld, (u32)pllfm, (u32)parent_freq);
+
+	current_freq = parent_freq * pllm / plld;
+
+	if (pllfm) {
+		u64 tmp;
+
+		tmp = parent_freq * pllfm;
+		do_div(tmp, plld);
+		tmp >>= PLL_16FFT_FREQ_CTRL1_FB_DIV_FRAC_BITS;
+		current_freq += tmp;
+	}
+
+	return current_freq;
+}
+
+static int ti_pll_clk_enable(struct clk *clk)
+{
+	struct ti_pll_clk *pll = to_clk_pll(clk);
+	u32 ctrl;
+
+	ctrl = readl(pll->reg + PLL_16FFT_CTRL);
+	ctrl &= ~PLL_16FFT_CTRL_BYPASS_EN;
+	ctrl |= PLL_16FFT_CTRL_PLL_EN;
+	writel(ctrl, pll->reg + PLL_16FFT_CTRL);
+
+	return ti_pll_wait_for_lock(clk);
+}
+
+static int ti_pll_clk_disable(struct clk *clk)
+{
+	struct ti_pll_clk *pll = to_clk_pll(clk);
+	u32 ctrl;
+
+	ctrl = readl(pll->reg + PLL_16FFT_CTRL);
+	ctrl |= PLL_16FFT_CTRL_BYPASS_EN;
+	writel(ctrl, pll->reg + PLL_16FFT_CTRL);
+
+	return 0;
+}
+
+static const struct clk_ops ti_pll_clk_ops = {
+	.get_rate = ti_pll_clk_get_rate,
+	.set_rate = ti_pll_clk_set_rate,
+	.enable = ti_pll_clk_enable,
+	.disable = ti_pll_clk_disable,
+};
+
+struct clk *clk_register_ti_pll(const char *name, const char *parent_name,
+				void __iomem *reg)
+{
+	struct ti_pll_clk *pll;
+	int ret;
+	int i;
+	u32 cfg, ctrl, hsdiv_presence_bit, hsdiv_ctrl_offs;
+
+	pll = kzalloc(sizeof(*pll), GFP_KERNEL);
+	if (!pll)
+		return ERR_PTR(-ENOMEM);
+
+	pll->reg = reg;
+
+	ret = clk_register(&pll->clk, "ti-pll-clk", name, parent_name);
+	if (ret) {
+		printf("%s: failed to register: %d\n", __func__, ret);
+		kfree(pll);
+		return ERR_PTR(ret);
+	}
+
+	/* Unlock the PLL registers */
+	writel(PLL_KICK0_VALUE, pll->reg + PLL_KICK0);
+	writel(PLL_KICK1_VALUE, pll->reg + PLL_KICK1);
+
+	/* Enable all HSDIV outputs */
+	cfg = readl(pll->reg + PLL_16FFT_CFG);
+	for (i = 0; i < 16; i++) {
+		hsdiv_presence_bit = BIT(16 + i);
+		hsdiv_ctrl_offs = 0x80 + (i * 4);
+		/* Enable HSDIV output if present */
+		if ((hsdiv_presence_bit & cfg) != 0UL) {
+			ctrl = readl(pll->reg + hsdiv_ctrl_offs);
+			ctrl |= PLL_16FFT_HSDIV_CTRL_CLKOUT_EN;
+			writel(ctrl, pll->reg + hsdiv_ctrl_offs);
+		}
+	}
+
+	return &pll->clk;
+}
+
+U_BOOT_DRIVER(ti_pll_clk) = {
+	.name = "ti-pll-clk",
+	.id = UCLASS_CLK,
+	.ops = &ti_pll_clk_ops,
+	.flags = DM_FLAG_PRE_RELOC,
+};

include/k3-clk.h

@@ -0,0 +1,15 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * (C) Copyright 2020 - Texas Instruments Incorporated - http://www.ti.com
+ *      Tero Kristo <t-kristo@ti.com>
+ */
+
+#ifndef __K3_CLK_H__
+#define __K3_CLK_H__
+
+#include <linux/clk-provider.h>
+
+struct clk *clk_register_ti_pll(const char *name, const char *parent_name,
+				void __iomem *reg);
+
+#endif /* __K3_CLK_H__ */