clk: starfive: Add StarFive JH7110 PLL clock driver

Add driver for the StarFive JH7110 PLL clock controller
and they work by reading and setting syscon registers.

Co-developed-by: Emil Renner Berthing <[e-mail]>
Signed-off-by: Emil Renner Berthing <[e-mail]>
Signed-off-by: Xingyu Wu <[e-mail]>
Signed-off-by: Conor Dooley <[e-mail]>

MAINTAINERS

···
 F:	Documentation/devicetree/bindings/mmc/starfive*
 F:	drivers/mmc/host/dw_mmc-starfive.c
 
+STARFIVE JH7110 PLL CLOCK DRIVER
+M:	Xingyu Wu <[e-mail]>
+S:	Supported
+F:	Documentation/devicetree/bindings/clock/starfive,jh7110-pll.yaml
+F:	drivers/clk/starfive/clk-starfive-jh7110-pll.c
+
 STARFIVE JH7110 SYSCON
 M:	William Qiu <[e-mail]>
 M:	Xingyu Wu <[e-mail]>

drivers/clk/starfive/Kconfig

···
 	  Say Y or M here to support the audio clocks on the StarFive JH7100
 	  SoC.
 
+config CLK_STARFIVE_JH7110_PLL
+	bool "StarFive JH7110 PLL clock support"
+	depends on ARCH_STARFIVE || COMPILE_TEST
+	default ARCH_STARFIVE
+	help
+	  Say yes here to support the PLL clock controller on the
+	  StarFive JH7110 SoC.
+
 config CLK_STARFIVE_JH7110_SYS
 	bool "StarFive JH7110 system clock support"
 	depends on ARCH_STARFIVE || COMPILE_TEST

drivers/clk/starfive/Makefile

···
 obj-$(CONFIG_CLK_STARFIVE_JH7100)	+= clk-starfive-jh7100.o
 obj-$(CONFIG_CLK_STARFIVE_JH7100_AUDIO)	+= clk-starfive-jh7100-audio.o
 
+obj-$(CONFIG_CLK_STARFIVE_JH7110_PLL)	+= clk-starfive-jh7110-pll.o
 obj-$(CONFIG_CLK_STARFIVE_JH7110_SYS)	+= clk-starfive-jh7110-sys.o
 obj-$(CONFIG_CLK_STARFIVE_JH7110_AON)	+= clk-starfive-jh7110-aon.o

drivers/clk/starfive/clk-starfive-jh7110-pll.c

···
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * StarFive JH7110 PLL Clock Generator Driver
+ *
+ * Copyright (C) 2023 StarFive Technology Co., Ltd.
+ * Copyright (C) 2023 Emil Renner Berthing <[e-mail]>
+ *
+ * This driver is about to register JH7110 PLL clock generator and support ops.
+ * The JH7110 have three PLL clock, PLL0, PLL1 and PLL2.
+ * Each PLL clocks work in integer mode or fraction mode by some dividers,
+ * and the configuration registers and dividers are set in several syscon registers.
+ * The formula for calculating frequency is:
+ * Fvco = Fref * (NI + NF) / M / Q1
+ * Fref: OSC source clock rate
+ * NI: integer frequency dividing ratio of feedback divider, set by fbdiv[11:0].
+ * NF: fractional frequency dividing ratio, set by frac[23:0]. NF = frac[23:0] / 2^24 = 0 ~ 0.999.
+ * M: frequency dividing ratio of pre-divider, set by prediv[5:0].
+ * Q1: frequency dividing ratio of post divider, set by 2^postdiv1[1:0], eg. 1, 2, 4 or 8.
+ */
+
+#include <linux/bits.h>
+#include <linux/clk-provider.h>
+#include <linux/debugfs.h>
+#include <linux/device.h>
+#include <linux/kernel.h>
+#include <linux/mfd/syscon.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+
+#include <dt-bindings/clock/starfive,jh7110-crg.h>
+
+/* this driver expects a 24MHz input frequency from the oscillator */
+#define JH7110_PLL_OSC_RATE		24000000UL
+
+#define JH7110_PLL0_PD_OFFSET		0x18
+#define JH7110_PLL0_DACPD_SHIFT		24
+#define JH7110_PLL0_DACPD_MASK		BIT(24)
+#define JH7110_PLL0_DSMPD_SHIFT		25
+#define JH7110_PLL0_DSMPD_MASK		BIT(25)
+#define JH7110_PLL0_FBDIV_OFFSET	0x1c
+#define JH7110_PLL0_FBDIV_SHIFT		0
+#define JH7110_PLL0_FBDIV_MASK		GENMASK(11, 0)
+#define JH7110_PLL0_FRAC_OFFSET		0x20
+#define JH7110_PLL0_PREDIV_OFFSET	0x24
+
+#define JH7110_PLL1_PD_OFFSET		0x24
+#define JH7110_PLL1_DACPD_SHIFT		15
+#define JH7110_PLL1_DACPD_MASK		BIT(15)
+#define JH7110_PLL1_DSMPD_SHIFT		16
+#define JH7110_PLL1_DSMPD_MASK		BIT(16)
+#define JH7110_PLL1_FBDIV_OFFSET	0x24
+#define JH7110_PLL1_FBDIV_SHIFT		17
+#define JH7110_PLL1_FBDIV_MASK		GENMASK(28, 17)
+#define JH7110_PLL1_FRAC_OFFSET		0x28
+#define JH7110_PLL1_PREDIV_OFFSET	0x2c
+
+#define JH7110_PLL2_PD_OFFSET		0x2c
+#define JH7110_PLL2_DACPD_SHIFT		15
+#define JH7110_PLL2_DACPD_MASK		BIT(15)
+#define JH7110_PLL2_DSMPD_SHIFT		16
+#define JH7110_PLL2_DSMPD_MASK		BIT(16)
+#define JH7110_PLL2_FBDIV_OFFSET	0x2c
+#define JH7110_PLL2_FBDIV_SHIFT		17
+#define JH7110_PLL2_FBDIV_MASK		GENMASK(28, 17)
+#define JH7110_PLL2_FRAC_OFFSET		0x30
+#define JH7110_PLL2_PREDIV_OFFSET	0x34
+
+#define JH7110_PLL_FRAC_SHIFT		0
+#define JH7110_PLL_FRAC_MASK		GENMASK(23, 0)
+#define JH7110_PLL_POSTDIV1_SHIFT	28
+#define JH7110_PLL_POSTDIV1_MASK	GENMASK(29, 28)
+#define JH7110_PLL_PREDIV_SHIFT		0
+#define JH7110_PLL_PREDIV_MASK		GENMASK(5, 0)
+
+enum jh7110_pll_mode {
+	JH7110_PLL_MODE_FRACTION,
+	JH7110_PLL_MODE_INTEGER,
+};
+
+struct jh7110_pll_preset {
+	unsigned long freq;
+	u32 frac;		/* frac value should be decimals multiplied by 2^24 */
+	unsigned fbdiv    : 12;	/* fbdiv value should be 8 to 4095 */
+	unsigned prediv   :  6;
+	unsigned postdiv1 :  2;
+	unsigned mode     :  1;
+};
+
+struct jh7110_pll_info {
+	char *name;
+	const struct jh7110_pll_preset *presets;
+	unsigned int npresets;
+	struct {
+		unsigned int pd;
+		unsigned int fbdiv;
+		unsigned int frac;
+		unsigned int prediv;
+	} offsets;
+	struct {
+		u32 dacpd;
+		u32 dsmpd;
+		u32 fbdiv;
+	} masks;
+	struct {
+		char dacpd;
+		char dsmpd;
+		char fbdiv;
+	} shifts;
+};
+
+#define _JH7110_PLL(_idx, _name, _presets)				\
+	[_idx] = {							\
+		.name = _name,						\
+		.presets = _presets,					\
+		.npresets = ARRAY_SIZE(_presets),			\
+		.offsets = {						\
+			.pd = JH7110_PLL##_idx##_PD_OFFSET,		\
+			.fbdiv = JH7110_PLL##_idx##_FBDIV_OFFSET,	\
+			.frac = JH7110_PLL##_idx##_FRAC_OFFSET,		\
+			.prediv = JH7110_PLL##_idx##_PREDIV_OFFSET,	\
+		},							\
+		.masks = {						\
+			.dacpd = JH7110_PLL##_idx##_DACPD_MASK,		\
+			.dsmpd = JH7110_PLL##_idx##_DSMPD_MASK,		\
+			.fbdiv = JH7110_PLL##_idx##_FBDIV_MASK,		\
+		},							\
+		.shifts = {						\
+			.dacpd = JH7110_PLL##_idx##_DACPD_SHIFT,	\
+			.dsmpd = JH7110_PLL##_idx##_DSMPD_SHIFT,	\
+			.fbdiv = JH7110_PLL##_idx##_FBDIV_SHIFT,	\
+		},							\
+	}
+#define JH7110_PLL(idx, name, presets) _JH7110_PLL(idx, name, presets)
+
+struct jh7110_pll_data {
+	struct clk_hw hw;
+	unsigned int idx;
+};
+
+struct jh7110_pll_priv {
+	struct device *dev;
+	struct regmap *regmap;
+	struct jh7110_pll_data pll[JH7110_PLLCLK_END];
+};
+
+struct jh7110_pll_regvals {
+	u32 dacpd;
+	u32 dsmpd;
+	u32 fbdiv;
+	u32 frac;
+	u32 postdiv1;
+	u32 prediv;
+};
+
+/*
+ * Because the pll frequency is relatively fixed,
+ * it cannot be set arbitrarily, so it needs a specific configuration.
+ * PLL0 frequency should be multiple of 125MHz (USB frequency).
+ */
+static const struct jh7110_pll_preset jh7110_pll0_presets[] = {
+	{
+		.freq = 375000000,
+		.fbdiv = 125,
+		.prediv = 8,
+		.postdiv1 = 0,
+		.mode = JH7110_PLL_MODE_INTEGER,
+	}, {
+		.freq = 500000000,
+		.fbdiv = 125,
+		.prediv = 6,
+		.postdiv1 = 0,
+		.mode = JH7110_PLL_MODE_INTEGER,
+	}, {
+		.freq = 625000000,
+		.fbdiv = 625,
+		.prediv = 24,
+		.postdiv1 = 0,
+		.mode = JH7110_PLL_MODE_INTEGER,
+	}, {
+		.freq = 750000000,
+		.fbdiv = 125,
+		.prediv = 4,
+		.postdiv1 = 0,
+		.mode = JH7110_PLL_MODE_INTEGER,
+	}, {
+		.freq = 875000000,
+		.fbdiv = 875,
+		.prediv = 24,
+		.postdiv1 = 0,
+		.mode = JH7110_PLL_MODE_INTEGER,
+	}, {
+		.freq = 1000000000,
+		.fbdiv = 125,
+		.prediv = 3,
+		.postdiv1 = 0,
+		.mode = JH7110_PLL_MODE_INTEGER,
+	}, {
+		.freq = 1250000000,
+		.fbdiv = 625,
+		.prediv = 12,
+		.postdiv1 = 0,
+		.mode = JH7110_PLL_MODE_INTEGER,
+	}, {
+		.freq = 1375000000,
+		.fbdiv = 1375,
+		.prediv = 24,
+		.postdiv1 = 0,
+		.mode = JH7110_PLL_MODE_INTEGER,
+	}, {
+		.freq = 1500000000,
+		.fbdiv = 125,
+		.prediv = 2,
+		.postdiv1 = 0,
+		.mode = JH7110_PLL_MODE_INTEGER,
+	},
+};
+
+static const struct jh7110_pll_preset jh7110_pll1_presets[] = {
+	{
+		.freq = 1066000000,
+		.fbdiv = 533,
+		.prediv = 12,
+		.postdiv1 = 0,
+		.mode = JH7110_PLL_MODE_INTEGER,
+	}, {
+		.freq = 1200000000,
+		.fbdiv = 50,
+		.prediv = 1,
+		.postdiv1 = 0,
+		.mode = JH7110_PLL_MODE_INTEGER,
+	}, {
+		.freq = 1400000000,
+		.fbdiv = 350,
+		.prediv = 6,
+		.postdiv1 = 0,
+		.mode = JH7110_PLL_MODE_INTEGER,
+	}, {
+		.freq = 1600000000,
+		.fbdiv = 200,
+		.prediv = 3,
+		.postdiv1 = 0,
+		.mode = JH7110_PLL_MODE_INTEGER,
+	},
+};
+
+static const struct jh7110_pll_preset jh7110_pll2_presets[] = {
+	{
+		.freq = 1188000000,
+		.fbdiv = 99,
+		.prediv = 2,
+		.postdiv1 = 0,
+		.mode = JH7110_PLL_MODE_INTEGER,
+	}, {
+		.freq = 1228800000,
+		.fbdiv = 256,
+		.prediv = 5,
+		.postdiv1 = 0,
+		.mode = JH7110_PLL_MODE_INTEGER,
+	},
+};
+
+static const struct jh7110_pll_info jh7110_plls[JH7110_PLLCLK_END] = {
+	JH7110_PLL(JH7110_PLLCLK_PLL0_OUT, "pll0_out", jh7110_pll0_presets),
+	JH7110_PLL(JH7110_PLLCLK_PLL1_OUT, "pll1_out", jh7110_pll1_presets),
+	JH7110_PLL(JH7110_PLLCLK_PLL2_OUT, "pll2_out", jh7110_pll2_presets),
+};
+
+static struct jh7110_pll_data *jh7110_pll_data_from(struct clk_hw *hw)
+{
+	return container_of(hw, struct jh7110_pll_data, hw);
+}
+
+static struct jh7110_pll_priv *jh7110_pll_priv_from(struct jh7110_pll_data *pll)
+{
+	return container_of(pll, struct jh7110_pll_priv, pll[pll->idx]);
+}
+
+static void jh7110_pll_regvals_get(struct regmap *regmap,
+				   const struct jh7110_pll_info *info,
+				   struct jh7110_pll_regvals *ret)
+{
+	u32 val;
+
+	regmap_read(regmap, info->offsets.pd, &val);
+	ret->dacpd = (val & info->masks.dacpd) >> info->shifts.dacpd;
+	ret->dsmpd = (val & info->masks.dsmpd) >> info->shifts.dsmpd;
+
+	regmap_read(regmap, info->offsets.fbdiv, &val);
+	ret->fbdiv = (val & info->masks.fbdiv) >> info->shifts.fbdiv;
+
+	regmap_read(regmap, info->offsets.frac, &val);
+	ret->frac = (val & JH7110_PLL_FRAC_MASK) >> JH7110_PLL_FRAC_SHIFT;
+	ret->postdiv1 = (val & JH7110_PLL_POSTDIV1_MASK) >> JH7110_PLL_POSTDIV1_SHIFT;
+
+	regmap_read(regmap, info->offsets.prediv, &val);
+	ret->prediv = (val & JH7110_PLL_PREDIV_MASK) >> JH7110_PLL_PREDIV_SHIFT;
+}
+
+static unsigned long jh7110_pll_recalc_rate(struct clk_hw *hw, unsigned long parent_rate)
+{
+	struct jh7110_pll_data *pll = jh7110_pll_data_from(hw);
+	struct jh7110_pll_priv *priv = jh7110_pll_priv_from(pll);
+	struct jh7110_pll_regvals val;
+	unsigned long rate;
+
+	jh7110_pll_regvals_get(priv->regmap, &jh7110_plls[pll->idx], &val);
+
+	/*
+	 * dacpd = dsmpd = 0: fraction mode
+	 * dacpd = dsmpd = 1: integer mode, frac value ignored
+	 *
+	 * rate = parent * (fbdiv + frac/2^24) / prediv / 2^postdiv1
+	 *      = (parent * fbdiv + parent * frac / 2^24) / (prediv * 2^postdiv1)
+	 */
+	if (val.dacpd == 0 && val.dsmpd == 0)
+		rate = parent_rate * val.frac / (1UL << 24);
+	else if (val.dacpd == 1 && val.dsmpd == 1)
+		rate = 0;
+	else
+		return 0;
+
+	rate += parent_rate * val.fbdiv;
+	rate /= val.prediv << val.postdiv1;
+
+	return rate;
+}
+
+static int jh7110_pll_determine_rate(struct clk_hw *hw, struct clk_rate_request *req)
+{
+	struct jh7110_pll_data *pll = jh7110_pll_data_from(hw);
+	const struct jh7110_pll_info *info = &jh7110_plls[pll->idx];
+	const struct jh7110_pll_preset *selected = &info->presets[0];
+	unsigned int idx;
+
+	/* if the parent rate doesn't match our expectations the presets won't work */
+	if (req->best_parent_rate != JH7110_PLL_OSC_RATE) {
+		req->rate = jh7110_pll_recalc_rate(hw, req->best_parent_rate);
+		return 0;
+	}
+
+	/* find highest rate lower or equal to the requested rate */
+	for (idx = 1; idx < info->npresets; idx++) {
+		const struct jh7110_pll_preset *val = &info->presets[idx];
+
+		if (req->rate < val->freq)
+			break;
+
+		selected = val;
+	}
+
+	req->rate = selected->freq;
+	return 0;
+}
+
+static int jh7110_pll_set_rate(struct clk_hw *hw, unsigned long rate,
+			       unsigned long parent_rate)
+{
+	struct jh7110_pll_data *pll = jh7110_pll_data_from(hw);
+	struct jh7110_pll_priv *priv = jh7110_pll_priv_from(pll);
+	const struct jh7110_pll_info *info = &jh7110_plls[pll->idx];
+	const struct jh7110_pll_preset *val;
+	unsigned int idx;
+
+	/* if the parent rate doesn't match our expectations the presets won't work */
+	if (parent_rate != JH7110_PLL_OSC_RATE)
+		return -EINVAL;
+
+	for (idx = 0, val = &info->presets[0]; idx < info->npresets; idx++, val++) {
+		if (val->freq == rate)
+			goto found;
+	}
+	return -EINVAL;
+
+found:
+	if (val->mode == JH7110_PLL_MODE_FRACTION)
+		regmap_update_bits(priv->regmap, info->offsets.frac, JH7110_PLL_FRAC_MASK,
+				   val->frac << JH7110_PLL_FRAC_SHIFT);
+
+	regmap_update_bits(priv->regmap, info->offsets.pd, info->masks.dacpd,
+			   (u32)val->mode << info->shifts.dacpd);
+	regmap_update_bits(priv->regmap, info->offsets.pd, info->masks.dsmpd,
+			   (u32)val->mode << info->shifts.dsmpd);
+	regmap_update_bits(priv->regmap, info->offsets.prediv, JH7110_PLL_PREDIV_MASK,
+			   (u32)val->prediv << JH7110_PLL_PREDIV_SHIFT);
+	regmap_update_bits(priv->regmap, info->offsets.fbdiv, info->masks.fbdiv,
+			   val->fbdiv << info->shifts.fbdiv);
+	regmap_update_bits(priv->regmap, info->offsets.frac, JH7110_PLL_POSTDIV1_MASK,
+			   (u32)val->postdiv1 << JH7110_PLL_POSTDIV1_SHIFT);
+
+	return 0;
+}
+
+#ifdef CONFIG_DEBUG_FS
+static int jh7110_pll_registers_read(struct seq_file *s, void *unused)
+{
+	struct jh7110_pll_data *pll = s->private;
+	struct jh7110_pll_priv *priv = jh7110_pll_priv_from(pll);
+	struct jh7110_pll_regvals val;
+
+	jh7110_pll_regvals_get(priv->regmap, &jh7110_plls[pll->idx], &val);
+
+	seq_printf(s, "fbdiv=%u\n"
+		      "frac=%u\n"
+		      "prediv=%u\n"
+		      "postdiv1=%u\n"
+		      "dacpd=%u\n"
+		      "dsmpd=%u\n",
+		      val.fbdiv, val.frac, val.prediv, val.postdiv1,
+		      val.dacpd, val.dsmpd);
+
+	return 0;
+}
+
+static int jh7110_pll_registers_open(struct inode *inode, struct file *f)
+{
+	return single_open(f, jh7110_pll_registers_read, inode->i_private);
+}
+
+static const struct file_operations jh7110_pll_registers_ops = {
+	.owner = THIS_MODULE,
+	.open = jh7110_pll_registers_open,
+	.release = single_release,
+	.read = seq_read,
+	.llseek = seq_lseek
+};
+
+static void jh7110_pll_debug_init(struct clk_hw *hw, struct dentry *dentry)
+{
+	struct jh7110_pll_data *pll = jh7110_pll_data_from(hw);
+
+	debugfs_create_file("registers", 0400, dentry, pll,
+			    &jh7110_pll_registers_ops);
+}
+#else
+#define jh7110_pll_debug_init NULL
+#endif
+
+static const struct clk_ops jh7110_pll_ops = {
+	.recalc_rate = jh7110_pll_recalc_rate,
+	.determine_rate = jh7110_pll_determine_rate,
+	.set_rate = jh7110_pll_set_rate,
+	.debug_init = jh7110_pll_debug_init,
+};
+
+static struct clk_hw *jh7110_pll_get(struct of_phandle_args *clkspec, void *data)
+{
+	struct jh7110_pll_priv *priv = data;
+	unsigned int idx = clkspec->args[0];
+
+	if (idx < JH7110_PLLCLK_END)
+		return &priv->pll[idx].hw;
+
+	return ERR_PTR(-EINVAL);
+}
+
+static int jh7110_pll_probe(struct platform_device *pdev)
+{
+	struct jh7110_pll_priv *priv;
+	unsigned int idx;
+	int ret;
+
+	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	priv->dev = &pdev->dev;
+	priv->regmap = syscon_node_to_regmap(priv->dev->of_node->parent);
+	if (IS_ERR(priv->regmap))
+		return PTR_ERR(priv->regmap);
+
+	for (idx = 0; idx < JH7110_PLLCLK_END; idx++) {
+		struct clk_parent_data parents = {
+			.index = 0,
+		};
+		struct clk_init_data init = {
+			.name = jh7110_plls[idx].name,
+			.ops = &jh7110_pll_ops,
+			.parent_data = &parents,
+			.num_parents = 1,
+			.flags = 0,
+		};
+		struct jh7110_pll_data *pll = &priv->pll[idx];
+
+		pll->hw.init = &init;
+		pll->idx = idx;
+
+		ret = devm_clk_hw_register(&pdev->dev, &pll->hw);
+		if (ret)
+			return ret;
+	}
+
+	return devm_of_clk_add_hw_provider(&pdev->dev, jh7110_pll_get, priv);
+}
+
+static const struct of_device_id jh7110_pll_match[] = {
+	{ .compatible = "starfive,jh7110-pll" },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, jh7110_pll_match);
+
+static struct platform_driver jh7110_pll_driver = {
+	.driver = {
+		.name = "clk-starfive-jh7110-pll",
+		.of_match_table = jh7110_pll_match,
+	},
+};
+builtin_platform_driver_probe(jh7110_pll_driver, jh7110_pll_probe);