drivers/clk/renesas/clk-mstp.c - linux - Git at Google

 /*
  * R-Car MSTP clocks
  *
  * Copyright (C) 2013 Ideas On Board SPRL
  * Copyright (C) 2015 Glider bvba
  *
  * Contact: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
  * the Free Software Foundation; version 2 of the License.
  */

 #include <linux/clk.h>
 #include <linux/clk-provider.h>
 #include <linux/clkdev.h>
 #include <linux/clk/renesas.h>
 #include <linux/device.h>
 #include <linux/io.h>
 #include <linux/of.h>
 #include <linux/of_address.h>
 #include <linux/pm_clock.h>
 #include <linux/pm_domain.h>
 #include <linux/spinlock.h>

 /*
  * MSTP clocks. We can't use standard gate clocks as we need to poll on the
  * status register when enabling the clock.
  */

 #define MSTP_MAX_CLOCKS		32

 /**
  * struct mstp_clock_group - MSTP gating clocks group
  *
  * @data: clocks in this group
  * @smstpcr: module stop control register
  * @mstpsr: module stop status register (optional)
  * @lock: protects writes to SMSTPCR
  * @width_8bit: registers are 8-bit, not 32-bit
  */
 struct mstp_clock_group {
 	struct clk_onecell_data data;
 	void __iomem *smstpcr;
 	void __iomem *mstpsr;
 	spinlock_t lock;
 	bool width_8bit;
 };

 /**
  * struct mstp_clock - MSTP gating clock
  * @hw: handle between common and hardware-specific interfaces
  * @bit_index: control bit index
  * @group: MSTP clocks group
  */
 struct mstp_clock {
 	struct clk_hw hw;
 	u32 bit_index;
 	struct mstp_clock_group *group;
 };

 #define to_mstp_clock(_hw) container_of(_hw, struct mstp_clock, hw)

 static inline u32 cpg_mstp_read(struct mstp_clock_group *group,
 				u32 __iomem *reg)
 {
 	return group->width_8bit ? readb(reg) : readl(reg);
 }

 static inline void cpg_mstp_write(struct mstp_clock_group *group, u32 val,
 				  u32 __iomem *reg)
 {
 	group->width_8bit ? writeb(val, reg) : writel(val, reg);
 }

 static int cpg_mstp_clock_endisable(struct clk_hw *hw, bool enable)
 {
 	struct mstp_clock *clock = to_mstp_clock(hw);
 	struct mstp_clock_group *group = clock->group;
 	u32 bitmask = BIT(clock->bit_index);
 	unsigned long flags;
 	unsigned int i;
 	u32 value;

 	spin_lock_irqsave(&group->lock, flags);

 	value = cpg_mstp_read(group, group->smstpcr);
 	if (enable)
 		value &= ~bitmask;
 	else
 		value |= bitmask;
 	cpg_mstp_write(group, value, group->smstpcr);

 	if (!group->mstpsr) {
 		/* dummy read to ensure write has completed */
 		cpg_mstp_read(group, group->smstpcr);
 		barrier_data(group->smstpcr);
 	}

 	spin_unlock_irqrestore(&group->lock, flags);

 	if (!enable || !group->mstpsr)
 		return 0;

 	for (i = 1000; i > 0; --i) {
 		if (!(cpg_mstp_read(group, group->mstpsr) & bitmask))
 			break;
 		cpu_relax();
 	}

 	if (!i) {
 		pr_err("%s: failed to enable %p[%d]\n", __func__,
 		       group->smstpcr, clock->bit_index);
 		return -ETIMEDOUT;
 	}

 	return 0;
 }

 static int cpg_mstp_clock_enable(struct clk_hw *hw)
 {
 	return cpg_mstp_clock_endisable(hw, true);
 }

 static void cpg_mstp_clock_disable(struct clk_hw *hw)
 {
 	cpg_mstp_clock_endisable(hw, false);
 }

 static int cpg_mstp_clock_is_enabled(struct clk_hw *hw)
 {
 	struct mstp_clock *clock = to_mstp_clock(hw);
 	struct mstp_clock_group *group = clock->group;
 	u32 value;

 	if (group->mstpsr)
 		value = cpg_mstp_read(group, group->mstpsr);
 	else
 		value = cpg_mstp_read(group, group->smstpcr);

 	return !(value & BIT(clock->bit_index));
 }

 static const struct clk_ops cpg_mstp_clock_ops = {
 	.enable = cpg_mstp_clock_enable,
 	.disable = cpg_mstp_clock_disable,
 	.is_enabled = cpg_mstp_clock_is_enabled,
 };

 static struct clk * __init cpg_mstp_clock_register(const char *name,
 	const char *parent_name, unsigned int index,
 	struct mstp_clock_group *group)
 {
 	struct clk_init_data init;
 	struct mstp_clock *clock;
 	struct clk *clk;

 	clock = kzalloc(sizeof(*clock), GFP_KERNEL);
 	if (!clock)
 		return ERR_PTR(-ENOMEM);

 	init.name = name;
 	init.ops = &cpg_mstp_clock_ops;
 	init.flags = CLK_IS_BASIC | CLK_SET_RATE_PARENT;
 	/* INTC-SYS is the module clock of the GIC, and must not be disabled */
 	if (!strcmp(name, "intc-sys")) {
 		pr_debug("MSTP %s setting CLK_IS_CRITICAL\n", name);
 		init.flags |= CLK_IS_CRITICAL;
 	}
 	init.parent_names = &parent_name;
 	init.num_parents = 1;

 	clock->bit_index = index;
 	clock->group = group;
 	clock->hw.init = &init;

 	clk = clk_register(NULL, &clock->hw);

 	if (IS_ERR(clk))
 		kfree(clock);

 	return clk;
 }

 static void __init cpg_mstp_clocks_init(struct device_node *np)
 {
 	struct mstp_clock_group *group;
 	const char *idxname;
 	struct clk **clks;
 	unsigned int i;

 	group = kzalloc(sizeof(*group), GFP_KERNEL);
 	clks = kmalloc_array(MSTP_MAX_CLOCKS, sizeof(*clks), GFP_KERNEL);
 	if (group == NULL || clks == NULL) {
 		kfree(group);
 		kfree(clks);
 		return;
 	}

 	spin_lock_init(&group->lock);
 	group->data.clks = clks;

 	group->smstpcr = of_iomap(np, 0);
 	group->mstpsr = of_iomap(np, 1);

 	if (group->smstpcr == NULL) {
 		pr_err("%s: failed to remap SMSTPCR\n", __func__);
 		kfree(group);
 		kfree(clks);
 		return;
 	}

 	if (of_device_is_compatible(np, "renesas,r7s72100-mstp-clocks"))
 		group->width_8bit = true;

 	for (i = 0; i < MSTP_MAX_CLOCKS; ++i)
 		clks[i] = ERR_PTR(-ENOENT);

 	if (of_find_property(np, "clock-indices", &i))
 		idxname = "clock-indices";
 	else
 		idxname = "renesas,clock-indices";

 	for (i = 0; i < MSTP_MAX_CLOCKS; ++i) {
 		const char *parent_name;
 		const char *name;
 		u32 clkidx;
 		int ret;

 		/* Skip clocks with no name. */
 		ret = of_property_read_string_index(np, "clock-output-names",
 						    i, &name);
 		if (ret < 0 || strlen(name) == 0)
 			continue;

 		parent_name = of_clk_get_parent_name(np, i);
 		ret = of_property_read_u32_index(np, idxname, i, &clkidx);
 		if (parent_name == NULL || ret < 0)
 			break;

 		if (clkidx >= MSTP_MAX_CLOCKS) {
 			pr_err("%s: invalid clock %s %s index %u\n",
 			       __func__, np->name, name, clkidx);
 			continue;
 		}

 		clks[clkidx] = cpg_mstp_clock_register(name, parent_name,
 						       clkidx, group);
 		if (!IS_ERR(clks[clkidx])) {
 			group->data.clk_num = max(group->data.clk_num,
 						  clkidx + 1);
 			/*
 			 * Register a clkdev to let board code retrieve the
 			 * clock by name and register aliases for non-DT
 			 * devices.
 			 *
 			 * FIXME: Remove this when all devices that require a
 			 * clock will be instantiated from DT.
 			 */
 			clk_register_clkdev(clks[clkidx], name, NULL);
 		} else {
 			pr_err("%s: failed to register %s %s clock (%ld)\n",
 			       __func__, np->name, name, PTR_ERR(clks[clkidx]));
 		}
 	}

 	of_clk_add_provider(np, of_clk_src_onecell_get, &group->data);
 }
 CLK_OF_DECLARE(cpg_mstp_clks, "renesas,cpg-mstp-clocks", cpg_mstp_clocks_init);

 int cpg_mstp_attach_dev(struct generic_pm_domain *unused, struct device *dev)
 {
 	struct device_node *np = dev->of_node;
 	struct of_phandle_args clkspec;
 	struct clk *clk;
 	int i = 0;
 	int error;

 	while (!of_parse_phandle_with_args(np, "clocks", "#clock-cells", i,
 					   &clkspec)) {
 		if (of_device_is_compatible(clkspec.np,
 					    "renesas,cpg-mstp-clocks"))
 			goto found;

 		/* BSC on r8a73a4/sh73a0 uses zb_clk instead of an mstp clock */
 		if (!strcmp(clkspec.np->name, "zb_clk"))
 			goto found;

 		of_node_put(clkspec.np);
 		i++;
 	}

 	return 0;

 found:
 	clk = of_clk_get_from_provider(&clkspec);
 	of_node_put(clkspec.np);

 	if (IS_ERR(clk))
 		return PTR_ERR(clk);

 	error = pm_clk_create(dev);
 	if (error) {
 		dev_err(dev, "pm_clk_create failed %d\n", error);
 		goto fail_put;
 	}

 	error = pm_clk_add_clk(dev, clk);
 	if (error) {
 		dev_err(dev, "pm_clk_add_clk %pC failed %d\n", clk, error);
 		goto fail_destroy;
 	}

 	return 0;

 fail_destroy:
 	pm_clk_destroy(dev);
 fail_put:
 	clk_put(clk);
 	return error;
 }

 void cpg_mstp_detach_dev(struct generic_pm_domain *unused, struct device *dev)
 {
 	if (!pm_clk_no_clocks(dev))
 		pm_clk_destroy(dev);
 }

 void __init cpg_mstp_add_clk_domain(struct device_node *np)
 {
 	struct generic_pm_domain *pd;
 	u32 ncells;

 	if (of_property_read_u32(np, "#power-domain-cells", &ncells)) {
 		pr_warn("%pOF lacks #power-domain-cells\n", np);
 		return;
 	}

 	pd = kzalloc(sizeof(*pd), GFP_KERNEL);
 	if (!pd)
 		return;

 	pd->name = np->name;
 	pd->flags = GENPD_FLAG_PM_CLK | GENPD_FLAG_ACTIVE_WAKEUP;
 	pd->attach_dev = cpg_mstp_attach_dev;
 	pd->detach_dev = cpg_mstp_detach_dev;
 	pm_genpd_init(pd, &pm_domain_always_on_gov, false);

 	of_genpd_add_provider_simple(np, pd);
 }
	/*
	* R-Car MSTP clocks
	*
	* Copyright (C) 2013 Ideas On Board SPRL
	* Copyright (C) 2015 Glider bvba
	*
	* Contact: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License as published by
	* the Free Software Foundation; version 2 of the License.
	*/

	#include <linux/clk.h>
	#include <linux/clk-provider.h>
	#include <linux/clkdev.h>
	#include <linux/clk/renesas.h>
	#include <linux/device.h>
	#include <linux/io.h>
	#include <linux/of.h>
	#include <linux/of_address.h>
	#include <linux/pm_clock.h>
	#include <linux/pm_domain.h>
	#include <linux/spinlock.h>

	/*
	* MSTP clocks. We can't use standard gate clocks as we need to poll on the
	* status register when enabling the clock.
	*/

	#define MSTP_MAX_CLOCKS 32

	/**
	* struct mstp_clock_group - MSTP gating clocks group
	*
	* @data: clocks in this group
	* @smstpcr: module stop control register
	* @mstpsr: module stop status register (optional)
	* @lock: protects writes to SMSTPCR
	* @width_8bit: registers are 8-bit, not 32-bit
	*/
	struct mstp_clock_group {
	struct clk_onecell_data data;
	void __iomem *smstpcr;
	void __iomem *mstpsr;
	spinlock_t lock;
	bool width_8bit;
	};

	/**
	* struct mstp_clock - MSTP gating clock
	* @hw: handle between common and hardware-specific interfaces
	* @bit_index: control bit index
	* @group: MSTP clocks group
	*/
	struct mstp_clock {
	struct clk_hw hw;
	u32 bit_index;
	struct mstp_clock_group *group;
	};

	#define to_mstp_clock(_hw) container_of(_hw, struct mstp_clock, hw)

	static inline u32 cpg_mstp_read(struct mstp_clock_group *group,
	u32 __iomem *reg)
	{
	return group->width_8bit ? readb(reg) : readl(reg);
	}

	static inline void cpg_mstp_write(struct mstp_clock_group *group, u32 val,
	u32 __iomem *reg)
	{
	group->width_8bit ? writeb(val, reg) : writel(val, reg);
	}

	static int cpg_mstp_clock_endisable(struct clk_hw *hw, bool enable)
	{
	struct mstp_clock *clock = to_mstp_clock(hw);
	struct mstp_clock_group *group = clock->group;
	u32 bitmask = BIT(clock->bit_index);
	unsigned long flags;
	unsigned int i;
	u32 value;

	spin_lock_irqsave(&group->lock, flags);

	value = cpg_mstp_read(group, group->smstpcr);
	if (enable)
	value &= ~bitmask;
	else
	value \|= bitmask;
	cpg_mstp_write(group, value, group->smstpcr);

	if (!group->mstpsr) {
	/* dummy read to ensure write has completed */
	cpg_mstp_read(group, group->smstpcr);
	barrier_data(group->smstpcr);
	}

	spin_unlock_irqrestore(&group->lock, flags);

	if (!enable \|\| !group->mstpsr)
	return 0;

	for (i = 1000; i > 0; --i) {
	if (!(cpg_mstp_read(group, group->mstpsr) & bitmask))
	break;
	cpu_relax();
	}

	if (!i) {
	pr_err("%s: failed to enable %p[%d]\n", __func__,
	group->smstpcr, clock->bit_index);
	return -ETIMEDOUT;
	}

	return 0;
	}

	static int cpg_mstp_clock_enable(struct clk_hw *hw)
	{
	return cpg_mstp_clock_endisable(hw, true);
	}

	static void cpg_mstp_clock_disable(struct clk_hw *hw)
	{
	cpg_mstp_clock_endisable(hw, false);
	}

	static int cpg_mstp_clock_is_enabled(struct clk_hw *hw)
	{
	struct mstp_clock *clock = to_mstp_clock(hw);
	struct mstp_clock_group *group = clock->group;
	u32 value;

	if (group->mstpsr)
	value = cpg_mstp_read(group, group->mstpsr);
	else
	value = cpg_mstp_read(group, group->smstpcr);

	return !(value & BIT(clock->bit_index));
	}

	static const struct clk_ops cpg_mstp_clock_ops = {
	.enable = cpg_mstp_clock_enable,
	.disable = cpg_mstp_clock_disable,
	.is_enabled = cpg_mstp_clock_is_enabled,
	};

	static struct clk * __init cpg_mstp_clock_register(const char *name,
	const char *parent_name, unsigned int index,
	struct mstp_clock_group *group)
	{
	struct clk_init_data init;
	struct mstp_clock *clock;
	struct clk *clk;

	clock = kzalloc(sizeof(*clock), GFP_KERNEL);
	if (!clock)
	return ERR_PTR(-ENOMEM);

	init.name = name;
	init.ops = &cpg_mstp_clock_ops;
	init.flags = CLK_IS_BASIC \| CLK_SET_RATE_PARENT;
	/* INTC-SYS is the module clock of the GIC, and must not be disabled */
	if (!strcmp(name, "intc-sys")) {
	pr_debug("MSTP %s setting CLK_IS_CRITICAL\n", name);
	init.flags \|= CLK_IS_CRITICAL;
	}
	init.parent_names = &parent_name;
	init.num_parents = 1;

	clock->bit_index = index;
	clock->group = group;
	clock->hw.init = &init;

	clk = clk_register(NULL, &clock->hw);

	if (IS_ERR(clk))
	kfree(clock);

	return clk;
	}

	static void __init cpg_mstp_clocks_init(struct device_node *np)
	{
	struct mstp_clock_group *group;
	const char *idxname;
	struct clk **clks;
	unsigned int i;

	group = kzalloc(sizeof(*group), GFP_KERNEL);
	clks = kmalloc_array(MSTP_MAX_CLOCKS, sizeof(*clks), GFP_KERNEL);
	if (group == NULL \|\| clks == NULL) {
	kfree(group);
	kfree(clks);
	return;
	}

	spin_lock_init(&group->lock);
	group->data.clks = clks;

	group->smstpcr = of_iomap(np, 0);
	group->mstpsr = of_iomap(np, 1);

	if (group->smstpcr == NULL) {
	pr_err("%s: failed to remap SMSTPCR\n", __func__);
	kfree(group);
	kfree(clks);
	return;
	}

	if (of_device_is_compatible(np, "renesas,r7s72100-mstp-clocks"))
	group->width_8bit = true;

	for (i = 0; i < MSTP_MAX_CLOCKS; ++i)
	clks[i] = ERR_PTR(-ENOENT);

	if (of_find_property(np, "clock-indices", &i))
	idxname = "clock-indices";
	else
	idxname = "renesas,clock-indices";

	for (i = 0; i < MSTP_MAX_CLOCKS; ++i) {
	const char *parent_name;
	const char *name;
	u32 clkidx;
	int ret;

	/* Skip clocks with no name. */
	ret = of_property_read_string_index(np, "clock-output-names",
	i, &name);
	if (ret < 0 \|\| strlen(name) == 0)
	continue;

	parent_name = of_clk_get_parent_name(np, i);
	ret = of_property_read_u32_index(np, idxname, i, &clkidx);
	if (parent_name == NULL \|\| ret < 0)
	break;

	if (clkidx >= MSTP_MAX_CLOCKS) {
	pr_err("%s: invalid clock %s %s index %u\n",
	__func__, np->name, name, clkidx);
	continue;
	}

	clks[clkidx] = cpg_mstp_clock_register(name, parent_name,
	clkidx, group);
	if (!IS_ERR(clks[clkidx])) {
	group->data.clk_num = max(group->data.clk_num,
	clkidx + 1);
	/*
	* Register a clkdev to let board code retrieve the
	* clock by name and register aliases for non-DT
	* devices.
	*
	* FIXME: Remove this when all devices that require a
	* clock will be instantiated from DT.
	*/
	clk_register_clkdev(clks[clkidx], name, NULL);
	} else {
	pr_err("%s: failed to register %s %s clock (%ld)\n",
	__func__, np->name, name, PTR_ERR(clks[clkidx]));
	}
	}

	of_clk_add_provider(np, of_clk_src_onecell_get, &group->data);
	}
	CLK_OF_DECLARE(cpg_mstp_clks, "renesas,cpg-mstp-clocks", cpg_mstp_clocks_init);

	int cpg_mstp_attach_dev(struct generic_pm_domain unused, struct device dev)
	{
	struct device_node *np = dev->of_node;
	struct of_phandle_args clkspec;
	struct clk *clk;
	int i = 0;
	int error;

	while (!of_parse_phandle_with_args(np, "clocks", "#clock-cells", i,
	&clkspec)) {
	if (of_device_is_compatible(clkspec.np,
	"renesas,cpg-mstp-clocks"))
	goto found;

	/* BSC on r8a73a4/sh73a0 uses zb_clk instead of an mstp clock */
	if (!strcmp(clkspec.np->name, "zb_clk"))
	goto found;

	of_node_put(clkspec.np);
	i++;
	}

	return 0;

	found:
	clk = of_clk_get_from_provider(&clkspec);
	of_node_put(clkspec.np);

	if (IS_ERR(clk))
	return PTR_ERR(clk);

	error = pm_clk_create(dev);
	if (error) {
	dev_err(dev, "pm_clk_create failed %d\n", error);
	goto fail_put;
	}

	error = pm_clk_add_clk(dev, clk);
	if (error) {
	dev_err(dev, "pm_clk_add_clk %pC failed %d\n", clk, error);
	goto fail_destroy;
	}

	return 0;

	fail_destroy:
	pm_clk_destroy(dev);
	fail_put:
	clk_put(clk);
	return error;
	}

	void cpg_mstp_detach_dev(struct generic_pm_domain unused, struct device dev)
	{
	if (!pm_clk_no_clocks(dev))
	pm_clk_destroy(dev);
	}

	void __init cpg_mstp_add_clk_domain(struct device_node *np)
	{
	struct generic_pm_domain *pd;
	u32 ncells;

	if (of_property_read_u32(np, "#power-domain-cells", &ncells)) {
	pr_warn("%pOF lacks #power-domain-cells\n", np);
	return;
	}

	pd = kzalloc(sizeof(*pd), GFP_KERNEL);
	if (!pd)
	return;

	pd->name = np->name;
	pd->flags = GENPD_FLAG_PM_CLK \| GENPD_FLAG_ACTIVE_WAKEUP;
	pd->attach_dev = cpg_mstp_attach_dev;
	pd->detach_dev = cpg_mstp_detach_dev;
	pm_genpd_init(pd, &pm_domain_always_on_gov, false);

	of_genpd_add_provider_simple(np, pd);
	}