ARC: clk: introduce HSDK pll driver

HSDK board manages its clocks using various PLLs. These PLL have same
dividers and corresponding control registers mapped to different addresses.
So we add one common driver for such PLLs.

Each PLL on HSDK board consists of three dividers: IDIV, FBDIV and
ODIV. Output clock value is managed using these dividers.

We add pre-defined tables with supported rate values and appropriate
configurations of IDIV, FBDIV and ODIV for each value.

As of today we add support for PLLs that generate clock for the
HSDK arc cpus, system, ddr, AXI tunnel and hdmi.

By this patch we add support for several plls (arc cpus pll and others),
so we had to use two different init types: CLK_OF_DECLARE for arc cpus pll
and regular probing for others plls.
Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
Reviewed-by: Vineet Gupta <vgupta@synopsys.com>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>

Documentation/devicetree/bindings/clock/snps,hsdk-pll-clock.txt

+Binding for the HSDK Generic PLL clock
+
+This binding uses the common clock binding[1].
+
+[1] Documentation/devicetree/bindings/clock/clock-bindings.txt
+
+Required properties:
+- compatible: should be "snps,hsdk-<name>-pll-clock"
+  "snps,hsdk-core-pll-clock"
+  "snps,hsdk-gp-pll-clock"
+  "snps,hsdk-hdmi-pll-clock"
+- reg : should contain base register location and length.
+- clocks: shall be the input parent clock phandle for the PLL.
+- #clock-cells: from common clock binding; Should always be set to 0.
+
+Example:
+	input_clk: input-clk {
+		clock-frequency = <33333333>;
+		compatible = "fixed-clock";
+		#clock-cells = <0>;
+	};
+
+	cpu_clk: cpu-clk@0 {
+		compatible = "snps,hsdk-core-pll-clock";
+		reg = <0x00 0x10>;
+		#clock-cells = <0>;
+		clocks = <&input_clk>;
+	};

MAINTAINERS

@@ -12738,6 +12738,12 @@ F:	drivers/clocksource/arc_timer.c
 F:	drivers/tty/serial/arc_uart.c
 T:	git git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc.git
 
+SYNOPSYS ARC HSDK SDP pll clock driver
+M:	Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
+S:	Supported
+F:	drivers/clk/clk-hsdk-pll.c
+F:	Documentation/devicetree/bindings/clock/snps,hsdk-pll-clock.txt
+
 SYNOPSYS ARC SDP platform support
 M:	Alexey Brodkin <abrodkin@synopsys.com>
 S:	Supported

drivers/clk/Kconfig

@@ -31,6 +31,13 @@ config COMMON_CLK_WM831X
 
 source "drivers/clk/versatile/Kconfig"
 
+config CLK_HSDK
+	bool "PLL Driver for HSDK platform"
+	depends on OF || COMPILE_TEST
+	---help---
+	  This driver supports the HSDK core, system, ddr, tunnel and hdmi PLLs
+	  control.
+
 config COMMON_CLK_MAX77686
 	tristate "Clock driver for Maxim 77620/77686/77802 MFD"
 	depends on MFD_MAX77686 || MFD_MAX77620 || COMPILE_TEST

drivers/clk/Makefile

@@ -27,6 +27,7 @@ obj-$(CONFIG_COMMON_CLK_CS2000_CP)	+= clk-cs2000-cp.o
 obj-$(CONFIG_ARCH_EFM32)		+= clk-efm32gg.o
 obj-$(CONFIG_COMMON_CLK_GEMINI)		+= clk-gemini.o
 obj-$(CONFIG_ARCH_HIGHBANK)		+= clk-highbank.o
+obj-$(CONFIG_CLK_HSDK)			+= clk-hsdk-pll.o
 obj-$(CONFIG_COMMON_CLK_MAX77686)	+= clk-max77686.o
 obj-$(CONFIG_ARCH_MB86S7X)		+= clk-mb86s7x.o
 obj-$(CONFIG_ARCH_MOXART)		+= clk-moxart.o

drivers/clk/clk-hsdk-pll.c

+/*
+ * Synopsys HSDK SDP Generic PLL clock driver
+ *
+ * Copyright (C) 2017 Synopsys
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2. This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+
+#include <linux/clk-provider.h>
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+
+#define CGU_PLL_CTRL	0x000 /* ARC PLL control register */
+#define CGU_PLL_STATUS	0x004 /* ARC PLL status register */
+#define CGU_PLL_FMEAS	0x008 /* ARC PLL frequency measurement register */
+#define CGU_PLL_MON	0x00C /* ARC PLL monitor register */
+
+#define CGU_PLL_CTRL_ODIV_SHIFT		2
+#define CGU_PLL_CTRL_IDIV_SHIFT		4
+#define CGU_PLL_CTRL_FBDIV_SHIFT	9
+#define CGU_PLL_CTRL_BAND_SHIFT		20
+
+#define CGU_PLL_CTRL_ODIV_MASK		GENMASK(3, CGU_PLL_CTRL_ODIV_SHIFT)
+#define CGU_PLL_CTRL_IDIV_MASK		GENMASK(8, CGU_PLL_CTRL_IDIV_SHIFT)
+#define CGU_PLL_CTRL_FBDIV_MASK		GENMASK(15, CGU_PLL_CTRL_FBDIV_SHIFT)
+
+#define CGU_PLL_CTRL_PD			BIT(0)
+#define CGU_PLL_CTRL_BYPASS		BIT(1)
+
+#define CGU_PLL_STATUS_LOCK		BIT(0)
+#define CGU_PLL_STATUS_ERR		BIT(1)
+
+#define HSDK_PLL_MAX_LOCK_TIME		100 /* 100 us */
+
+#define CGU_PLL_SOURCE_MAX		1
+
+#define CORE_IF_CLK_THRESHOLD_HZ	500000000
+#define CREG_CORE_IF_CLK_DIV_1		0x0
+#define CREG_CORE_IF_CLK_DIV_2		0x1
+
+struct hsdk_pll_cfg {
+	u32 rate;
+	u32 idiv;
+	u32 fbdiv;
+	u32 odiv;
+	u32 band;
+};
+
+static const struct hsdk_pll_cfg asdt_pll_cfg[] = {
+	{ 100000000,  0, 11, 3, 0 },
+	{ 133000000,  0, 15, 3, 0 },
+	{ 200000000,  1, 47, 3, 0 },
+	{ 233000000,  1, 27, 2, 0 },
+	{ 300000000,  1, 35, 2, 0 },
+	{ 333000000,  1, 39, 2, 0 },
+	{ 400000000,  1, 47, 2, 0 },
+	{ 500000000,  0, 14, 1, 0 },
+	{ 600000000,  0, 17, 1, 0 },
+	{ 700000000,  0, 20, 1, 0 },
+	{ 800000000,  0, 23, 1, 0 },
+	{ 900000000,  1, 26, 0, 0 },
+	{ 1000000000, 1, 29, 0, 0 },
+	{ 1100000000, 1, 32, 0, 0 },
+	{ 1200000000, 1, 35, 0, 0 },
+	{ 1300000000, 1, 38, 0, 0 },
+	{ 1400000000, 1, 41, 0, 0 },
+	{ 1500000000, 1, 44, 0, 0 },
+	{ 1600000000, 1, 47, 0, 0 },
+	{}
+};
+
+static const struct hsdk_pll_cfg hdmi_pll_cfg[] = {
+	{ 297000000,  0, 21, 2, 0 },
+	{ 540000000,  0, 19, 1, 0 },
+	{ 594000000,  0, 21, 1, 0 },
+	{}
+};
+
+struct hsdk_pll_clk {
+	struct clk_hw hw;
+	void __iomem *regs;
+	void __iomem *spec_regs;
+	const struct hsdk_pll_devdata *pll_devdata;
+	struct device *dev;
+};
+
+struct hsdk_pll_devdata {
+	const struct hsdk_pll_cfg *pll_cfg;
+	int (*update_rate)(struct hsdk_pll_clk *clk, unsigned long rate,
+			   const struct hsdk_pll_cfg *cfg);
+};
+
+static int hsdk_pll_core_update_rate(struct hsdk_pll_clk *, unsigned long,
+				     const struct hsdk_pll_cfg *);
+static int hsdk_pll_comm_update_rate(struct hsdk_pll_clk *, unsigned long,
+				     const struct hsdk_pll_cfg *);
+
+static const struct hsdk_pll_devdata core_pll_devdata = {
+	.pll_cfg = asdt_pll_cfg,
+	.update_rate = hsdk_pll_core_update_rate,
+};
+
+static const struct hsdk_pll_devdata sdt_pll_devdata = {
+	.pll_cfg = asdt_pll_cfg,
+	.update_rate = hsdk_pll_comm_update_rate,
+};
+
+static const struct hsdk_pll_devdata hdmi_pll_devdata = {
+	.pll_cfg = hdmi_pll_cfg,
+	.update_rate = hsdk_pll_comm_update_rate,
+};
+
+static inline void hsdk_pll_write(struct hsdk_pll_clk *clk, u32 reg, u32 val)
+{
+	iowrite32(val, clk->regs + reg);
+}
+
+static inline u32 hsdk_pll_read(struct hsdk_pll_clk *clk, u32 reg)
+{
+	return ioread32(clk->regs + reg);
+}
+
+static inline void hsdk_pll_set_cfg(struct hsdk_pll_clk *clk,
+				    const struct hsdk_pll_cfg *cfg)
+{
+	u32 val = 0;
+
+	/* Powerdown and Bypass bits should be cleared */
+	val |= cfg->idiv << CGU_PLL_CTRL_IDIV_SHIFT;
+	val |= cfg->fbdiv << CGU_PLL_CTRL_FBDIV_SHIFT;
+	val |= cfg->odiv << CGU_PLL_CTRL_ODIV_SHIFT;
+	val |= cfg->band << CGU_PLL_CTRL_BAND_SHIFT;
+
+	dev_dbg(clk->dev, "write configurarion: %#x\n", val);
+
+	hsdk_pll_write(clk, CGU_PLL_CTRL, val);
+}
+
+static inline bool hsdk_pll_is_locked(struct hsdk_pll_clk *clk)
+{
+	return !!(hsdk_pll_read(clk, CGU_PLL_STATUS) & CGU_PLL_STATUS_LOCK);
+}
+
+static inline bool hsdk_pll_is_err(struct hsdk_pll_clk *clk)
+{
+	return !!(hsdk_pll_read(clk, CGU_PLL_STATUS) & CGU_PLL_STATUS_ERR);
+}
+
+static inline struct hsdk_pll_clk *to_hsdk_pll_clk(struct clk_hw *hw)
+{
+	return container_of(hw, struct hsdk_pll_clk, hw);
+}
+
+static unsigned long hsdk_pll_recalc_rate(struct clk_hw *hw,
+					  unsigned long parent_rate)
+{
+	u32 val;
+	u64 rate;
+	u32 idiv, fbdiv, odiv;
+	struct hsdk_pll_clk *clk = to_hsdk_pll_clk(hw);
+
+	val = hsdk_pll_read(clk, CGU_PLL_CTRL);
+
+	dev_dbg(clk->dev, "current configurarion: %#x\n", val);
+
+	/* Check if PLL is disabled */
+	if (val & CGU_PLL_CTRL_PD)
+		return 0;
+
+	/* Check if PLL is bypassed */
+	if (val & CGU_PLL_CTRL_BYPASS)
+		return parent_rate;
+
+	/* input divider = reg.idiv + 1 */
+	idiv = 1 + ((val & CGU_PLL_CTRL_IDIV_MASK) >> CGU_PLL_CTRL_IDIV_SHIFT);
+	/* fb divider = 2*(reg.fbdiv + 1) */
+	fbdiv = 2 * (1 + ((val & CGU_PLL_CTRL_FBDIV_MASK) >> CGU_PLL_CTRL_FBDIV_SHIFT));
+	/* output divider = 2^(reg.odiv) */
+	odiv = 1 << ((val & CGU_PLL_CTRL_ODIV_MASK) >> CGU_PLL_CTRL_ODIV_SHIFT);
+
+	rate = (u64)parent_rate * fbdiv;
+	do_div(rate, idiv * odiv);
+
+	return rate;
+}
+
+static long hsdk_pll_round_rate(struct clk_hw *hw, unsigned long rate,
+				unsigned long *prate)
+{
+	int i;
+	unsigned long best_rate;
+	struct hsdk_pll_clk *clk = to_hsdk_pll_clk(hw);
+	const struct hsdk_pll_cfg *pll_cfg = clk->pll_devdata->pll_cfg;
+
+	if (pll_cfg[0].rate == 0)
+		return -EINVAL;
+
+	best_rate = pll_cfg[0].rate;
+
+	for (i = 1; pll_cfg[i].rate != 0; i++) {
+		if (abs(rate - pll_cfg[i].rate) < abs(rate - best_rate))
+			best_rate = pll_cfg[i].rate;
+	}
+
+	dev_dbg(clk->dev, "chosen best rate: %lu\n", best_rate);
+
+	return best_rate;
+}
+
+static int hsdk_pll_comm_update_rate(struct hsdk_pll_clk *clk,
+				     unsigned long rate,
+				     const struct hsdk_pll_cfg *cfg)
+{
+	hsdk_pll_set_cfg(clk, cfg);
+
+	/*
+	 * Wait until CGU relocks and check error status.
+	 * If after timeout CGU is unlocked yet return error.
+	 */
+	udelay(HSDK_PLL_MAX_LOCK_TIME);
+	if (!hsdk_pll_is_locked(clk))
+		return -ETIMEDOUT;
+
+	if (hsdk_pll_is_err(clk))
+		return -EINVAL;
+
+	return 0;
+}
+
+static int hsdk_pll_core_update_rate(struct hsdk_pll_clk *clk,
+				     unsigned long rate,
+				     const struct hsdk_pll_cfg *cfg)
+{
+	/*
+	 * When core clock exceeds 500MHz, the divider for the interface
+	 * clock must be programmed to div-by-2.
+	 */
+	if (rate > CORE_IF_CLK_THRESHOLD_HZ)
+		iowrite32(CREG_CORE_IF_CLK_DIV_2, clk->spec_regs);
+
+	hsdk_pll_set_cfg(clk, cfg);
+
+	/*
+	 * Wait until CGU relocks and check error status.
+	 * If after timeout CGU is unlocked yet return error.
+	 */
+	udelay(HSDK_PLL_MAX_LOCK_TIME);
+	if (!hsdk_pll_is_locked(clk))
+		return -ETIMEDOUT;
+
+	if (hsdk_pll_is_err(clk))
+		return -EINVAL;
+
+	/*
+	 * Program divider to div-by-1 if we succesfuly set core clock below
+	 * 500MHz threshold.
+	 */
+	if (rate <= CORE_IF_CLK_THRESHOLD_HZ)
+		iowrite32(CREG_CORE_IF_CLK_DIV_1, clk->spec_regs);
+
+	return 0;
+}
+
+static int hsdk_pll_set_rate(struct clk_hw *hw, unsigned long rate,
+			     unsigned long parent_rate)
+{
+	int i;
+	struct hsdk_pll_clk *clk = to_hsdk_pll_clk(hw);
+	const struct hsdk_pll_cfg *pll_cfg = clk->pll_devdata->pll_cfg;
+
+	for (i = 0; pll_cfg[i].rate != 0; i++) {
+		if (pll_cfg[i].rate == rate) {
+			return clk->pll_devdata->update_rate(clk, rate,
+							     &pll_cfg[i]);
+		}
+	}
+
+	dev_err(clk->dev, "invalid rate=%ld, parent_rate=%ld\n", rate,
+			parent_rate);
+
+	return -EINVAL;
+}
+
+static const struct clk_ops hsdk_pll_ops = {
+	.recalc_rate = hsdk_pll_recalc_rate,
+	.round_rate = hsdk_pll_round_rate,
+	.set_rate = hsdk_pll_set_rate,
+};
+
+static int hsdk_pll_clk_probe(struct platform_device *pdev)
+{
+	int ret;
+	struct resource *mem;
+	const char *parent_name;
+	unsigned int num_parents;
+	struct hsdk_pll_clk *pll_clk;
+	struct clk_init_data init = { };
+	struct device *dev = &pdev->dev;
+
+	pll_clk = devm_kzalloc(dev, sizeof(*pll_clk), GFP_KERNEL);
+	if (!pll_clk)
+		return -ENOMEM;
+
+	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	pll_clk->regs = devm_ioremap_resource(dev, mem);
+	if (IS_ERR(pll_clk->regs))
+		return PTR_ERR(pll_clk->regs);
+
+	init.name = dev->of_node->name;
+	init.ops = &hsdk_pll_ops;
+	parent_name = of_clk_get_parent_name(dev->of_node, 0);
+	init.parent_names = &parent_name;
+	num_parents = of_clk_get_parent_count(dev->of_node);
+	if (num_parents == 0 || num_parents > CGU_PLL_SOURCE_MAX) {
+		dev_err(dev, "wrong clock parents number: %u\n", num_parents);
+		return -EINVAL;
+	}
+	init.num_parents = num_parents;
+
+	pll_clk->hw.init = &init;
+	pll_clk->dev = dev;
+	pll_clk->pll_devdata = of_device_get_match_data(dev);
+
+	if (!pll_clk->pll_devdata) {
+		dev_err(dev, "No OF match data provided\n");
+		return -EINVAL;
+	}
+
+	ret = devm_clk_hw_register(dev, &pll_clk->hw);
+	if (ret) {
+		dev_err(dev, "failed to register %s clock\n", init.name);
+		return ret;
+	}
+
+	return of_clk_add_hw_provider(dev->of_node, of_clk_hw_simple_get,
+			&pll_clk->hw);
+}
+
+static int hsdk_pll_clk_remove(struct platform_device *pdev)
+{
+	of_clk_del_provider(pdev->dev.of_node);
+	return 0;
+}
+
+static void __init of_hsdk_pll_clk_setup(struct device_node *node)
+{
+	int ret;
+	const char *parent_name;
+	unsigned int num_parents;
+	struct hsdk_pll_clk *pll_clk;
+	struct clk_init_data init = { };
+
+	pll_clk = kzalloc(sizeof(*pll_clk), GFP_KERNEL);
+	if (!pll_clk)
+		return;
+
+	pll_clk->regs = of_iomap(node, 0);
+	if (!pll_clk->regs) {
+		pr_err("failed to map pll registers\n");
+		goto err_free_pll_clk;
+	}
+
+	pll_clk->spec_regs = of_iomap(node, 1);
+	if (!pll_clk->spec_regs) {
+		pr_err("failed to map pll registers\n");
+		goto err_unmap_comm_regs;
+	}
+
+	init.name = node->name;
+	init.ops = &hsdk_pll_ops;
+	parent_name = of_clk_get_parent_name(node, 0);
+	init.parent_names = &parent_name;
+	num_parents = of_clk_get_parent_count(node);
+	if (num_parents > CGU_PLL_SOURCE_MAX) {
+		pr_err("too much clock parents: %u\n", num_parents);
+		goto err_unmap_spec_regs;
+	}
+	init.num_parents = num_parents;
+
+	pll_clk->hw.init = &init;
+	pll_clk->pll_devdata = &core_pll_devdata;
+
+	ret = clk_hw_register(NULL, &pll_clk->hw);
+	if (ret) {
+		pr_err("failed to register %s clock\n", node->name);
+		goto err_unmap_spec_regs;
+	}
+
+	ret = of_clk_add_hw_provider(node, of_clk_hw_simple_get, &pll_clk->hw);
+	if (ret) {
+		pr_err("failed to add hw provider for %s clock\n", node->name);
+		goto err_unmap_spec_regs;
+	}
+
+	return;
+
+err_unmap_spec_regs:
+	iounmap(pll_clk->spec_regs);
+err_unmap_comm_regs:
+	iounmap(pll_clk->regs);
+err_free_pll_clk:
+	kfree(pll_clk);
+}
+
+/* Core PLL needed early for ARC cpus timers */
+CLK_OF_DECLARE(hsdk_pll_clock, "snps,hsdk-core-pll-clock",
+of_hsdk_pll_clk_setup);
+
+static const struct of_device_id hsdk_pll_clk_id[] = {
+	{ .compatible = "snps,hsdk-gp-pll-clock", .data = &sdt_pll_devdata},
+	{ .compatible = "snps,hsdk-hdmi-pll-clock", .data = &hdmi_pll_devdata},
+	{ }
+};
+
+static struct platform_driver hsdk_pll_clk_driver = {
+	.driver = {
+		.name = "hsdk-gp-pll-clock",
+		.of_match_table = hsdk_pll_clk_id,
+	},
+	.probe = hsdk_pll_clk_probe,
+	.remove = hsdk_pll_clk_remove,
+};
+builtin_platform_driver(hsdk_pll_clk_driver);