[PATCH 05/21] clock:Add driver for ADI ADSP-SC5xx PLL

[Arturs Artamonovs via B4 Relay <devnull+arturs.artamonovs.analog.com@kernel.org>]

From: Arturs Artamonovs <arturs.artamonovs@analog.com>

Implements clock tree, no dynamic pll rate change.

Signed-off-by: Arturs Artamonovs <Arturs.Artamonovs@analog.com>
Co-developed-by: Nathan Barrett-Morrison <nathan.morrison@timesys.com>
Signed-off-by: Nathan Barrett-Morrison <nathan.morrison@timesys.com>
Co-developed-by: Greg Malysa <greg.malysa@timesys.com>
Signed-off-by: Greg Malysa <greg.malysa@timesys.com>
---
 drivers/clk/adi/clk-adi-pll.c | 151 ++++++++++++++++++++++++++++++++++++++++++
 drivers/clk/adi/clk.h         |  99 +++++++++++++++++++++++++++
 2 files changed, 250 insertions(+)

diff --git a/drivers/clk/adi/clk-adi-pll.c b/drivers/clk/adi/clk-adi-pll.c
new file mode 100644
index 0000000000000000000000000000000000000000..39fcc78b3170c0aa5962af5268f499082efb3686
--- /dev/null
+++ b/drivers/clk/adi/clk-adi-pll.c
@@ -0,0 +1,151 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * CGU PLL driver for ADI SC59X processors
+ *
+ * Copyright 2022-2024 - Analog Devices Inc.
+ */
+
+#include <linux/clk-provider.h>
+#include <linux/io.h>
+#include <linux/slab.h>
+#include <linux/device.h>
+
+#include "clk.h"
+
+struct clk_sc5xx_cgu_pll {
+	struct clk_hw hw;
+	void __iomem *base;
+	spinlock_t *lock;
+	int prepared;
+	u32 mask;
+	u32 msel;
+	u32 m_offset;
+	u8 shift;
+};
+
+struct clk_sc5xx_cgu_pll *to_clk_sc5xx_cgu_pll(struct clk_hw *hw)
+{
+	return container_of(hw, struct clk_sc5xx_cgu_pll, hw);
+}
+
+static long sc5xx_cgu_pll_round_rate(struct clk_hw *hw, unsigned long rate,
+	unsigned long *parent_rate)
+{
+	struct clk_sc5xx_cgu_pll *pll = to_clk_sc5xx_cgu_pll(hw);
+	unsigned long m, m2, new_rate, nr2, prate2;
+	unsigned long prate = *parent_rate;
+	struct clk_hw *parent_hw;
+	int parent_inc;
+
+	parent_hw = clk_hw_get_parent(hw);
+
+	m = rate / prate;
+
+	if (m > pll->msel) {
+		/* cannot scale this far, need bigger input */
+		parent_inc = m / pll->msel;
+		prate = clk_hw_round_rate(parent_hw, prate * (parent_inc + 1));
+	} else if (m == 0) {
+		pr_err("%s: Cannot use VCO to reduce parent clock rate, requested %lu, clamping to %lu\n",
+			__func__, rate, prate);
+		return prate;
+	}
+
+	new_rate = prate * m;
+
+	if (new_rate != rate) {
+		/*
+		 * Check if we could get an integer match by halving parent rate since we
+		 * know at least about the DF bit before the VCO, although we don't know
+		 * if we're already using it or not
+		 */
+		prate2 = clk_hw_round_rate(parent_hw, prate / 2);
+		m2 = rate / prate2;
+		nr2 = prate * m2;
+		if (m2 <= pll->msel && nr2 == rate) {
+			m = m2;
+			new_rate = nr2;
+			prate = prate2;
+		}
+	}
+
+	*parent_rate = prate;
+	return new_rate;
+}
+
+static unsigned long sc5xx_cgu_pll_recalc_rate(struct clk_hw *hw,
+	unsigned long parent_rate)
+{
+	struct clk_sc5xx_cgu_pll *pll = to_clk_sc5xx_cgu_pll(hw);
+	u32 reg = readl(pll->base);
+	u32 m = ((reg & pll->mask) >> pll->shift) + pll->m_offset;
+
+	if (m == 0)
+		m = pll->msel;
+
+	return parent_rate * m;
+
+}
+
+static int sc5xx_cgu_pll_set_rate(struct clk_hw *hw, unsigned long rate,
+	unsigned long parent_rate)
+{
+	struct clk_sc5xx_cgu_pll *pll = to_clk_sc5xx_cgu_pll(hw);
+	u32 m;
+
+	m = (rate / parent_rate) - pll->m_offset;
+
+	if (m >= pll->msel)
+		m = 0;
+
+	/* reminder for implementation: lock around read/modify to control reg */
+	pr_err("%s: set_rate not permitted yet, but we would write %d to m\n", __func__,
+		m);
+	return -ENOENT;
+}
+
+static const struct clk_ops clk_sc5xx_cgu_pll_ops = {
+	.recalc_rate = sc5xx_cgu_pll_recalc_rate,
+	.round_rate = sc5xx_cgu_pll_round_rate,
+	.set_rate = sc5xx_cgu_pll_set_rate,
+};
+
+struct clk *sc5xx_cgu_pll(const char *name, const char *parent_name,
+	void __iomem *base, u8 shift, u8 width, u32 m_offset,
+		spinlock_t *lock)
+{
+	struct clk_sc5xx_cgu_pll *pll;
+	struct clk *clk;
+	struct clk_init_data init;
+
+	pll = kzalloc(sizeof(*pll), GFP_KERNEL);
+	if (!pll)
+		return ERR_PTR(-ENOMEM);
+
+	init.name = name;
+	init.flags = CLK_SET_RATE_PARENT;
+	init.parent_names = &parent_name;
+	init.num_parents = 1;
+	init.ops = &clk_sc5xx_cgu_pll_ops;
+
+	pll->base = base;
+	pll->hw.init = &init;
+	pll->lock = lock;
+	pll->shift = shift;
+	pll->mask = GENMASK(width-1, 0) << shift;
+	pll->msel = pll->mask + 1;
+	pll->m_offset = m_offset;
+
+	clk = clk_register(NULL, &pll->hw);
+	if (IS_ERR(clk)) {
+		pr_err("%s: Failed to register, code %lu\n", __func__,
+			PTR_ERR(clk));
+	}
+
+	return clk;
+}
+
+MODULE_DESCRIPTION("Analog Devices CLock PLL driver");
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Greg Malysa <greg.malysa@timesys.com>");
+
diff --git a/drivers/clk/adi/clk.h b/drivers/clk/adi/clk.h
new file mode 100644
index 0000000000000000000000000000000000000000..e17aa719c2170149a6a1a60dd4390a29f06e7296
--- /dev/null
+++ b/drivers/clk/adi/clk.h
@@ -0,0 +1,99 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Clock support for ADI processors
+ *
+ * Copyright 2022-2024 - Analog Devices Inc.
+ */
+
+#ifndef CLK_ADI_CLK_H
+#define CLK_ADI_CLK_H
+
+#include <linux/clk.h>
+
+#define CGU_CTL         0x00
+#define CGU_PLLCTL      0x04
+#define CGU_STAT        0x08
+#define CGU_DIV         0x0C
+#define CGU_CLKOUTSEL   0x10
+#define CGU_OSCWDCTL    0x14
+#define CGU_TSCTL       0x18
+#define CGU_TSVALUE0    0x1C
+#define CGU_TSVALUE1    0x20
+#define CGU_TSCOUNT0    0x24
+#define CGU_TSCOUNT1    0x28
+#define CGU_CCBF_DIS    0x2C
+#define CGU_CCBF_STAT   0x30
+#define CGU_SCBF_DIS    0x38
+#define CGU_SCBF_STAT   0x3C
+#define CGU_DIVEX       0x40
+#define CGU_REVID       0x48
+
+#define CDU_CFG0     0x00
+#define CDU_CFG1     0x04
+#define CDU_CFG2     0x08
+#define CDU_CFG3     0x0C
+#define CDU_CFG4     0x10
+#define CDU_CFG5     0x14
+#define CDU_CFG6     0x18
+#define CDU_CFG7     0x1C
+#define CDU_CFG8     0x20
+#define CDU_CFG9     0x24
+#define CDU_CFG10    0x28
+#define CDU_CFG11    0x2C
+#define CDU_CFG12    0x30
+#define CDU_CFG13    0x34
+#define CDU_CFG14    0x38
+
+#define PLL3_OFFSET 0x2c
+
+#define CDU_CLKINSEL 0x44
+
+#define CGU_MSEL_SHIFT 8
+#define CGU_MSEL_WIDTH 7
+
+#define PLL3_MSEL_SHIFT 4
+#define PLL3_MSEL_WIDTH 7
+
+#define CDU_MUX_SIZE 4
+#define CDU_MUX_SHIFT 1
+#define CDU_MUX_WIDTH 2
+#define CDU_EN_BIT 0
+
+struct clk_sc5xx_cgu_pll *to_clk_sc5xx_cgu_pll(struct clk_hw *hw);
+
+struct clk *sc5xx_cgu_pll(const char *name, const char *parent_name,
+	void __iomem *base, u8 shift, u8 width, u32 m_offset, spinlock_t *lock);
+
+/**
+ * All CDU clock muxes are the same size
+ */
+static inline struct clk *cdu_mux(const char *name, void __iomem *reg,
+	const char * const *parents, spinlock_t *cdu_lock)
+{
+	return clk_register_mux(NULL, name, parents, CDU_MUX_SIZE,
+		CLK_SET_RATE_PARENT, reg, CDU_MUX_SHIFT, CDU_MUX_WIDTH, 0,
+		cdu_lock);
+}
+
+static inline struct clk *cgu_divider(const char *name, const char *parent,
+	void __iomem *reg, u8 shift, u8 width, u8 extra_flags, spinlock_t *cdu_lock)
+{
+	return clk_register_divider(NULL, name, parent, CLK_SET_RATE_PARENT,
+		reg, shift, width, CLK_DIVIDER_MAX_AT_ZERO | extra_flags, cdu_lock);
+}
+
+static inline struct clk *cdu_gate(const char *name, const char *parent,
+	void __iomem *reg, u32 flags, spinlock_t *cdu_lock)
+{
+	return clk_register_gate(NULL, name, parent, CLK_SET_RATE_PARENT | flags,
+		reg, CDU_EN_BIT, 0, cdu_lock);
+}
+
+static inline struct clk *cgu_gate(const char *name, const char *parent,
+	void __iomem *reg, u8 bit, spinlock_t *cdu_lock)
+{
+	return clk_register_gate(NULL, name, parent, CLK_SET_RATE_PARENT, reg, bit,
+		CLK_GATE_SET_TO_DISABLE, cdu_lock);
+}
+
+#endif

-- 
2.25.1