[v13,1/4] clk: ralink: add clock driver for mt7621 SoC

diff --git a/drivers/clk/Kconfig b/drivers/clk/Kconfig
index 1d1891b9cad2..e80918be8e9c 100644
--- a/drivers/clk/Kconfig
+++ b/drivers/clk/Kconfig
@@ -390,6 +390,7 @@  source "drivers/clk/meson/Kconfig"
 source "drivers/clk/mstar/Kconfig"
 source "drivers/clk/mvebu/Kconfig"
 source "drivers/clk/qcom/Kconfig"
+source "drivers/clk/ralink/Kconfig"
 source "drivers/clk/renesas/Kconfig"
 source "drivers/clk/rockchip/Kconfig"
 source "drivers/clk/samsung/Kconfig"
diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile
index 9b582b3fca34..5f06879d7fe9 100644
--- a/drivers/clk/Makefile
+++ b/drivers/clk/Makefile
@@ -100,6 +100,7 @@  obj-$(CONFIG_COMMON_CLK_NXP)		+= nxp/
 obj-$(CONFIG_MACH_PISTACHIO)		+= pistachio/
 obj-$(CONFIG_COMMON_CLK_PXA)		+= pxa/
 obj-$(CONFIG_COMMON_CLK_QCOM)		+= qcom/
+obj-y					+= ralink/
 obj-y					+= renesas/
 obj-$(CONFIG_ARCH_ROCKCHIP)		+= rockchip/
 obj-$(CONFIG_COMMON_CLK_SAMSUNG)	+= samsung/
diff --git a/drivers/clk/ralink/Kconfig b/drivers/clk/ralink/Kconfig
new file mode 100644
index 000000000000..6580d5edc676
--- /dev/null
+++ b/drivers/clk/ralink/Kconfig
@@ -0,0 +1,11 @@ 
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# MediaTek Mt7621 Clock Driver
+#
+config CLK_MT7621
+	bool "Clock driver for MediaTek MT7621"
+	depends on SOC_MT7621 || COMPILE_TEST
+	default SOC_MT7621
+	select MFD_SYSCON
+	help
+	  This driver supports MediaTek MT7621 basic clocks.
diff --git a/drivers/clk/ralink/Makefile b/drivers/clk/ralink/Makefile
new file mode 100644
index 000000000000..cf6f9216379d
--- /dev/null
+++ b/drivers/clk/ralink/Makefile
@@ -0,0 +1,2 @@ 
+# SPDX-License-Identifier: GPL-2.0
+obj-$(CONFIG_CLK_MT7621) += clk-mt7621.o
diff --git a/drivers/clk/ralink/clk-mt7621.c b/drivers/clk/ralink/clk-mt7621.c
new file mode 100644
index 000000000000..857da1e274be
--- /dev/null
+++ b/drivers/clk/ralink/clk-mt7621.c
@@ -0,0 +1,495 @@ 
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Mediatek MT7621 Clock Driver
+ * Author: Sergio Paracuellos <sergio.paracuellos@gmail.com>
+ */
+
+#include <linux/bitfield.h>
+#include <linux/bitops.h>
+#include <linux/clk-provider.h>
+#include <linux/clk.h>
+#include <linux/mfd/syscon.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/slab.h>
+#include <dt-bindings/clock/mt7621-clk.h>
+
+/* Configuration registers */
+#define SYSC_REG_SYSTEM_CONFIG0         0x10
+#define SYSC_REG_SYSTEM_CONFIG1         0x14
+#define SYSC_REG_CLKCFG0		0x2c
+#define SYSC_REG_CLKCFG1		0x30
+#define SYSC_REG_CUR_CLK_STS		0x44
+#define MEMC_REG_CPU_PLL		0x648
+
+#define XTAL_MODE_SEL_MASK		GENMASK(8, 6)
+#define CPU_CLK_SEL_MASK		GENMASK(31, 30)
+#define CUR_CPU_FDIV_MASK		GENMASK(12, 8)
+#define CUR_CPU_FFRAC_MASK		GENMASK(4, 0)
+#define CPU_PLL_PREDIV_MASK		GENMASK(13, 12)
+#define CPU_PLL_FBDIV_MASK		GENMASK(10, 4)
+
+struct mt7621_clk_priv {
+	struct regmap *sysc;
+	struct regmap *memc;
+};
+
+struct mt7621_clk {
+	struct clk_hw hw;
+	struct mt7621_clk_priv *priv;
+};
+
+struct mt7621_fixed_clk {
+	u8 idx;
+	const char *name;
+	const char *parent_name;
+	unsigned long rate;
+	struct clk_hw *hw;
+};
+
+struct mt7621_gate {
+	u8 idx;
+	const char *name;
+	const char *parent_name;
+	struct mt7621_clk_priv *priv;
+	u32 bit_idx;
+	struct clk_hw hw;
+};
+
+#define GATE(_id, _name, _pname, _shift)	\
+	{					\
+		.idx		= _id,		\
+		.name		= _name,	\
+		.parent_name	= _pname,	\
+		.bit_idx	= _shift	\
+	}
+
+static struct mt7621_gate mt7621_gates[] = {
+	GATE(MT7621_CLK_HSDMA, "hsdma", "150m", BIT(5)),
+	GATE(MT7621_CLK_FE, "fe", "250m", BIT(6)),
+	GATE(MT7621_CLK_SP_DIVTX, "sp_divtx", "270m", BIT(7)),
+	GATE(MT7621_CLK_TIMER, "timer", "50m", BIT(8)),
+	GATE(MT7621_CLK_PCM, "pcm", "270m", BIT(11)),
+	GATE(MT7621_CLK_PIO, "pio", "50m", BIT(13)),
+	GATE(MT7621_CLK_GDMA, "gdma", "bus", BIT(14)),
+	GATE(MT7621_CLK_NAND, "nand", "125m", BIT(15)),
+	GATE(MT7621_CLK_I2C, "i2c", "50m", BIT(16)),
+	GATE(MT7621_CLK_I2S, "i2s", "270m", BIT(17)),
+	GATE(MT7621_CLK_SPI, "spi", "bus", BIT(18)),
+	GATE(MT7621_CLK_UART1, "uart1", "50m", BIT(19)),
+	GATE(MT7621_CLK_UART2, "uart2", "50m", BIT(20)),
+	GATE(MT7621_CLK_UART3, "uart3", "50m", BIT(21)),
+	GATE(MT7621_CLK_ETH, "eth", "50m", BIT(23)),
+	GATE(MT7621_CLK_PCIE0, "pcie0", "125m", BIT(24)),
+	GATE(MT7621_CLK_PCIE1, "pcie1", "125m", BIT(25)),
+	GATE(MT7621_CLK_PCIE2, "pcie2", "125m", BIT(26)),
+	GATE(MT7621_CLK_CRYPTO, "crypto", "250m", BIT(29)),
+	GATE(MT7621_CLK_SHXC, "shxc", "50m", BIT(30))
+};
+
+static inline struct mt7621_gate *to_mt7621_gate(struct clk_hw *hw)
+{
+	return container_of(hw, struct mt7621_gate, hw);
+}
+
+static int mt7621_gate_enable(struct clk_hw *hw)
+{
+	struct mt7621_gate *clk_gate = to_mt7621_gate(hw);
+	struct regmap *sysc = clk_gate->priv->sysc;
+
+	return regmap_update_bits(sysc, SYSC_REG_CLKCFG1,
+				  clk_gate->bit_idx, clk_gate->bit_idx);
+}
+
+static void mt7621_gate_disable(struct clk_hw *hw)
+{
+	struct mt7621_gate *clk_gate = to_mt7621_gate(hw);
+	struct regmap *sysc = clk_gate->priv->sysc;
+
+	regmap_update_bits(sysc, SYSC_REG_CLKCFG1, clk_gate->bit_idx, 0);
+}
+
+static int mt7621_gate_is_enabled(struct clk_hw *hw)
+{
+	struct mt7621_gate *clk_gate = to_mt7621_gate(hw);
+	struct regmap *sysc = clk_gate->priv->sysc;
+	u32 val;
+
+	if (regmap_read(sysc, SYSC_REG_CLKCFG1, &val))
+		return 0;
+
+	return val & BIT(clk_gate->bit_idx);
+}
+
+static const struct clk_ops mt7621_gate_ops = {
+	.enable = mt7621_gate_enable,
+	.disable = mt7621_gate_disable,
+	.is_enabled = mt7621_gate_is_enabled,
+};
+
+static int mt7621_gate_ops_init(struct device *dev,
+				struct mt7621_gate *sclk)
+{
+	struct clk_init_data init = {
+		/*
+		 * Until now no clock driver existed so
+		 * these SoC drivers are not prepared
+		 * yet for the clock. We don't want kernel to
+		 * disable anything so we add CLK_IS_CRITICAL
+		 * flag here.
+		 */
+		.flags = CLK_SET_RATE_PARENT | CLK_IS_CRITICAL,
+		.num_parents = 1,
+		.parent_names = &sclk->parent_name,
+		.ops = &mt7621_gate_ops,
+		.name = sclk->name,
+	};
+
+	sclk->hw.init = &init;
+	return devm_clk_hw_register(dev, &sclk->hw);
+}
+
+static int mt7621_register_gates(struct device *dev,
+				 struct clk_hw_onecell_data *clk_data,
+				 struct mt7621_clk_priv *priv)
+{
+	struct clk_hw **hws = clk_data->hws;
+	struct mt7621_gate *sclk;
+	int ret, i;
+
+	for (i = 0; i < ARRAY_SIZE(mt7621_gates); i++) {
+		sclk = &mt7621_gates[i];
+		sclk->priv = priv;
+		ret = mt7621_gate_ops_init(dev, sclk);
+		if (ret) {
+			dev_err(dev, "Couldn't register clock %s\n", sclk->name);
+			goto err_clk_unreg;
+		}
+
+		hws[sclk->idx] = &sclk->hw;
+	}
+
+	return 0;
+
+err_clk_unreg:
+	while (--i >= 0) {
+		sclk = &mt7621_gates[i];
+		clk_hw_unregister(&sclk->hw);
+	}
+	return ret;
+}
+
+#define FIXED(_id, _name, _rate)		\
+	{					\
+		.idx		= _id,		\
+		.name		= _name,	\
+		.parent_name	= "xtal",	\
+		.rate		= _rate		\
+	}
+
+static struct mt7621_fixed_clk mt7621_fixed_clks[] = {
+	FIXED(MT7621_CLK_50M, "50m", 50000000),
+	FIXED(MT7621_CLK_125M, "125m", 125000000),
+	FIXED(MT7621_CLK_150M, "150m", 150000000),
+	FIXED(MT7621_CLK_250M, "250m", 250000000),
+	FIXED(MT7621_CLK_270M, "270m", 270000000),
+};
+
+static int mt7621_register_fixed_clocks(struct device *dev,
+					struct clk_hw_onecell_data *clk_data)
+{
+	struct clk_hw **hws = clk_data->hws;
+	struct mt7621_fixed_clk *sclk;
+	int ret, i;
+
+	for (i = 0; i < ARRAY_SIZE(mt7621_fixed_clks); i++) {
+		sclk = &mt7621_fixed_clks[i];
+		sclk->hw = clk_hw_register_fixed_rate(dev, sclk->name,
+						      sclk->parent_name, 0,
+						      sclk->rate);
+		if (IS_ERR(sclk->hw)) {
+			dev_err(dev, "Couldn't register clock %s\n", sclk->name);
+			ret = PTR_ERR(sclk->hw);
+			goto err_clk_unreg;
+		}
+
+		hws[sclk->idx] = sclk->hw;
+	}
+
+	return 0;
+
+err_clk_unreg:
+	while (--i >= 0) {
+		sclk = &mt7621_fixed_clks[i];
+		clk_hw_unregister_fixed_rate(sclk->hw);
+	}
+	return ret;
+}
+
+static inline struct mt7621_clk *to_mt7621_clk(struct clk_hw *hw)
+{
+	return container_of(hw, struct mt7621_clk, hw);
+}
+
+static unsigned long mt7621_xtal_recalc_rate(struct clk_hw *hw,
+					     unsigned long parent_rate)
+{
+	struct mt7621_clk *clk = to_mt7621_clk(hw);
+	struct regmap *sysc = clk->priv->sysc;
+	u32 val;
+
+	regmap_read(sysc, SYSC_REG_SYSTEM_CONFIG0, &val);
+	val = FIELD_GET(XTAL_MODE_SEL_MASK, val);
+
+	if (val <= 2)
+		return 20000000;
+	if (val <= 5)
+		return 40000000;
+
+	return 25000000;
+}
+
+static unsigned long mt7621_cpu_recalc_rate(struct clk_hw *hw,
+					    unsigned long xtal_clk)
+{
+	static const u32 prediv_tbl[] = { 0, 1, 2, 2 };
+	struct mt7621_clk *clk = to_mt7621_clk(hw);
+	struct regmap *sysc = clk->priv->sysc;
+	struct regmap *memc = clk->priv->memc;
+	u32 clkcfg, clk_sel, curclk, ffiv, ffrac;
+	u32 pll, prediv, fbdiv;
+	unsigned long cpu_clk;
+
+	regmap_read(sysc, SYSC_REG_CLKCFG0, &clkcfg);
+	clk_sel = FIELD_GET(CPU_CLK_SEL_MASK, clkcfg);
+
+	regmap_read(sysc, SYSC_REG_CUR_CLK_STS, &curclk);
+	ffiv = FIELD_GET(CUR_CPU_FDIV_MASK, curclk);
+	ffrac = FIELD_GET(CUR_CPU_FFRAC_MASK, curclk);
+
+	switch (clk_sel) {
+	case 0:
+		cpu_clk = 500000000;
+		break;
+	case 1:
+		regmap_read(memc, MEMC_REG_CPU_PLL, &pll);
+		fbdiv = FIELD_GET(CPU_PLL_FBDIV_MASK, pll);
+		prediv = FIELD_GET(CPU_PLL_PREDIV_MASK, pll);
+		cpu_clk = ((fbdiv + 1) * xtal_clk) >> prediv_tbl[prediv];
+		break;
+	default:
+		cpu_clk = xtal_clk;
+	}
+
+	return cpu_clk / ffiv * ffrac;
+}
+
+static unsigned long mt7621_bus_recalc_rate(struct clk_hw *hw,
+					    unsigned long parent_rate)
+{
+	return parent_rate / 4;
+}
+
+#define CLK_BASE(_name, _parent, _recalc) {				\
+	.init = &(struct clk_init_data) {				\
+		.name = _name,						\
+		.ops = &(const struct clk_ops) {			\
+			.recalc_rate = _recalc,				\
+		},							\
+		.parent_data = &(const struct clk_parent_data) {	\
+			.name = _parent,				\
+			.fw_name = _parent				\
+		},							\
+		.num_parents = _parent ? 1 : 0				\
+	},								\
+}
+
+static struct mt7621_clk mt7621_clks_base[] = {
+	{ CLK_BASE("xtal", NULL, mt7621_xtal_recalc_rate) },
+	{ CLK_BASE("cpu", "xtal", mt7621_cpu_recalc_rate) },
+	{ CLK_BASE("bus", "cpu", mt7621_bus_recalc_rate) },
+};
+
+static struct clk_hw *mt7621_clk_early[MT7621_CLK_MAX];
+
+static int mt7621_register_early_clocks(struct device_node *np,
+					struct clk_hw_onecell_data *clk_data,
+					struct mt7621_clk_priv *priv)
+{
+	struct clk_hw **hws = clk_data->hws;
+	struct mt7621_clk *sclk;
+	int ret, i, j;
+
+	for (i = 0; i < ARRAY_SIZE(mt7621_clks_base); i++) {
+		sclk = &mt7621_clks_base[i];
+		sclk->priv = priv;
+		ret = of_clk_hw_register(np, &sclk->hw);
+		if (ret) {
+			pr_err("Couldn't register top clock %i\n", i);
+			goto err_clk_unreg;
+		}
+
+		hws[i] = &sclk->hw;
+		mt7621_clk_early[i] = &sclk->hw;
+	}
+
+	for (j = i; j < MT7621_CLK_MAX; j++)
+		mt7621_clk_early[j] = ERR_PTR(-EPROBE_DEFER);
+
+	return 0;
+
+err_clk_unreg:
+	while (--i >= 0) {
+		sclk = &mt7621_clks_base[i];
+		clk_hw_unregister(&sclk->hw);
+	}
+	return ret;
+}
+
+static void __init mt7621_clk_init(struct device_node *node)
+{
+	struct mt7621_clk_priv *priv;
+	struct clk_hw_onecell_data *clk_data;
+	int ret, i, count;
+
+	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return;
+
+	priv->sysc = syscon_node_to_regmap(node);
+	if (IS_ERR(priv->sysc)) {
+		pr_err("Could not get sysc syscon regmap\n");
+		goto free_clk_priv;
+	}
+
+	priv->memc = syscon_regmap_lookup_by_phandle(node, "ralink,memctl");
+	if (IS_ERR(priv->memc)) {
+		pr_err("Could not get memc syscon regmap\n");
+		goto free_clk_priv;
+	}
+
+	count = ARRAY_SIZE(mt7621_clks_base) +
+		ARRAY_SIZE(mt7621_fixed_clks) + ARRAY_SIZE(mt7621_gates);
+	clk_data = kzalloc(struct_size(clk_data, hws, count), GFP_KERNEL);
+	if (!clk_data)
+		goto free_clk_priv;
+
+	ret = mt7621_register_early_clocks(node, clk_data, priv);
+	if (ret) {
+		pr_err("Couldn't register top clocks\n");
+		goto free_clk_data;
+	}
+
+	clk_data->num = count;
+
+	ret = of_clk_add_hw_provider(node, of_clk_hw_onecell_get, clk_data);
+	if (ret) {
+		pr_err("Couldn't add clk hw provider\n");
+		goto unreg_clk_top;
+	}
+
+	return;
+
+unreg_clk_top:
+	for (i = 0; i < ARRAY_SIZE(mt7621_clks_base); i++) {
+		struct mt7621_clk *sclk = &mt7621_clks_base[i];
+
+		clk_hw_unregister(&sclk->hw);
+	}
+
+free_clk_data:
+	kfree(clk_data);
+
+free_clk_priv:
+	kfree(priv);
+}
+CLK_OF_DECLARE_DRIVER(mt7621_clk, "mediatek,mt7621-sysc", mt7621_clk_init);
+
+static int mt7621_clk_probe(struct platform_device *pdev)
+{
+	struct device_node *np = pdev->dev.of_node;
+	struct clk_hw_onecell_data *clk_data;
+	struct device *dev = &pdev->dev;
+	struct mt7621_clk_priv *priv;
+	int ret, i, count;
+
+	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	priv->sysc = syscon_node_to_regmap(np);
+	if (IS_ERR(priv->sysc)) {
+		ret = PTR_ERR(priv->sysc);
+		dev_err(dev, "Could not get sysc syscon regmap\n");
+		return ret;
+	}
+
+	priv->memc = syscon_regmap_lookup_by_phandle(np, "ralink,memctl");
+	if (IS_ERR(priv->memc)) {
+		ret = PTR_ERR(priv->memc);
+		dev_err(dev, "Could not get memc syscon regmap\n");
+		return ret;
+	}
+
+	count = ARRAY_SIZE(mt7621_clks_base) +
+		ARRAY_SIZE(mt7621_fixed_clks) + ARRAY_SIZE(mt7621_gates);
+	clk_data = devm_kzalloc(dev, struct_size(clk_data, hws, count),
+				GFP_KERNEL);
+	if (!clk_data)
+		return -ENOMEM;
+
+	for (i = 0; i < ARRAY_SIZE(mt7621_clks_base); i++)
+		clk_data->hws[i] = mt7621_clk_early[i];
+
+	ret = mt7621_register_fixed_clocks(dev, clk_data);
+	if (ret) {
+		dev_err(dev, "Couldn't register fixed clocks\n");
+		return ret;
+	}
+
+	ret = mt7621_register_gates(dev, clk_data, priv);
+	if (ret) {
+		dev_err(dev, "Couldn't register fixed clock gates\n");
+		goto unreg_clk_fixed;
+	}
+
+	clk_data->num = count;
+
+	ret = devm_of_clk_add_hw_provider(dev, of_clk_hw_onecell_get, clk_data);
+	if (ret) {
+		dev_err(dev, "Couldn't add clk hw provider\n");
+		goto unreg_clk_gates;
+	}
+
+	return 0;
+
+unreg_clk_gates:
+	for (i = 0; i < ARRAY_SIZE(mt7621_gates); i++) {
+		struct mt7621_gate *sclk = &mt7621_gates[i];
+
+		clk_hw_unregister(&sclk->hw);
+	}
+
+unreg_clk_fixed:
+	for (i = 0; i < ARRAY_SIZE(mt7621_fixed_clks); i++) {
+		struct mt7621_fixed_clk *sclk = &mt7621_fixed_clks[i];
+
+		clk_hw_unregister_fixed_rate(sclk->hw);
+	}
+
+	return ret;
+}
+
+static const struct of_device_id mt7621_clk_of_match[] = {
+	{ .compatible = "mediatek,mt7621-sysc" },
+	{}
+};
+
+static struct platform_driver mt7621_clk_driver = {
+	.probe = mt7621_clk_probe,
+	.driver = {
+		.name = "mt7621-clk",
+		.of_match_table = mt7621_clk_of_match,
+	},
+};
+builtin_platform_driver(mt7621_clk_driver);