drivers/clk/renesas/clk-div6.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0
 /*
  * r8a7790 Common Clock Framework support
  *
  * Copyright (C) 2013  Renesas Solutions Corp.
  *
  * Contact: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
  */

 #include <linux/clk-provider.h>
 #include <linux/init.h>
 #include <linux/io.h>
 #include <linux/kernel.h>
 #include <linux/notifier.h>
 #include <linux/of.h>
 #include <linux/of_address.h>
 #include <linux/pm.h>
 #include <linux/slab.h>

 #include "clk-div6.h"

 #define CPG_DIV6_CKSTP		BIT(8)
 #define CPG_DIV6_DIV(d)		((d) & 0x3f)
 #define CPG_DIV6_DIV_MASK	0x3f

 /**
  * struct div6_clock - CPG 6 bit divider clock
  * @hw: handle between common and hardware-specific interfaces
  * @reg: IO-remapped register
  * @div: divisor value (1-64)
  * @src_shift: Shift to access the register bits to select the parent clock
  * @src_width: Number of register bits to select the parent clock (may be 0)
  * @parents: Array to map from valid parent clocks indices to hardware indices
  * @nb: Notifier block to save/restore clock state for system resume
  */
 struct div6_clock {
 	struct clk_hw hw;
 	void __iomem *reg;
 	unsigned int div;
 	u32 src_shift;
 	u32 src_width;
 	u8 *parents;
 	struct notifier_block nb;
 };

 #define to_div6_clock(_hw) container_of(_hw, struct div6_clock, hw)

 static int cpg_div6_clock_enable(struct clk_hw *hw)
 {
 	struct div6_clock *clock = to_div6_clock(hw);
 	u32 val;

 	val = (readl(clock->reg) & ~(CPG_DIV6_DIV_MASK | CPG_DIV6_CKSTP))
 	    | CPG_DIV6_DIV(clock->div - 1);
 	writel(val, clock->reg);

 	return 0;
 }

 static void cpg_div6_clock_disable(struct clk_hw *hw)
 {
 	struct div6_clock *clock = to_div6_clock(hw);
 	u32 val;

 	val = readl(clock->reg);
 	val |= CPG_DIV6_CKSTP;
 	/*
 	 * DIV6 clocks require the divisor field to be non-zero when stopping
 	 * the clock. However, some clocks (e.g. ZB on sh73a0) fail to be
 	 * re-enabled later if the divisor field is changed when stopping the
 	 * clock
 	 */
 	if (!(val & CPG_DIV6_DIV_MASK))
 		val |= CPG_DIV6_DIV_MASK;
 	writel(val, clock->reg);
 }

 static int cpg_div6_clock_is_enabled(struct clk_hw *hw)
 {
 	struct div6_clock *clock = to_div6_clock(hw);

 	return !(readl(clock->reg) & CPG_DIV6_CKSTP);
 }

 static unsigned long cpg_div6_clock_recalc_rate(struct clk_hw *hw,
 						unsigned long parent_rate)
 {
 	struct div6_clock *clock = to_div6_clock(hw);

 	return parent_rate / clock->div;
 }

 static unsigned int cpg_div6_clock_calc_div(unsigned long rate,
 					    unsigned long parent_rate)
 {
 	unsigned int div;

 	if (!rate)
 		rate = 1;

 	div = DIV_ROUND_CLOSEST(parent_rate, rate);
 	return clamp_t(unsigned int, div, 1, 64);
 }

 static long cpg_div6_clock_round_rate(struct clk_hw *hw, unsigned long rate,
 				      unsigned long *parent_rate)
 {
 	unsigned int div = cpg_div6_clock_calc_div(rate, *parent_rate);

 	return *parent_rate / div;
 }

 static int cpg_div6_clock_set_rate(struct clk_hw *hw, unsigned long rate,
 				   unsigned long parent_rate)
 {
 	struct div6_clock *clock = to_div6_clock(hw);
 	unsigned int div = cpg_div6_clock_calc_div(rate, parent_rate);
 	u32 val;

 	clock->div = div;

 	val = readl(clock->reg) & ~CPG_DIV6_DIV_MASK;
 	/* Only program the new divisor if the clock isn't stopped. */
 	if (!(val & CPG_DIV6_CKSTP))
 		writel(val | CPG_DIV6_DIV(clock->div - 1), clock->reg);

 	return 0;
 }

 static u8 cpg_div6_clock_get_parent(struct clk_hw *hw)
 {
 	struct div6_clock *clock = to_div6_clock(hw);
 	unsigned int i;
 	u8 hw_index;

 	if (clock->src_width == 0)
 		return 0;

 	hw_index = (readl(clock->reg) >> clock->src_shift) &
 		   (BIT(clock->src_width) - 1);
 	for (i = 0; i < clk_hw_get_num_parents(hw); i++) {
 		if (clock->parents[i] == hw_index)
 			return i;
 	}

 	pr_err("%s: %s DIV6 clock set to invalid parent %u\n",
 	       __func__, clk_hw_get_name(hw), hw_index);
 	return 0;
 }

 static int cpg_div6_clock_set_parent(struct clk_hw *hw, u8 index)
 {
 	struct div6_clock *clock = to_div6_clock(hw);
 	u8 hw_index;
 	u32 mask;

 	if (index >= clk_hw_get_num_parents(hw))
 		return -EINVAL;

 	mask = ~((BIT(clock->src_width) - 1) << clock->src_shift);
 	hw_index = clock->parents[index];

 	writel((readl(clock->reg) & mask) | (hw_index << clock->src_shift),
 	       clock->reg);

 	return 0;
 }

 static const struct clk_ops cpg_div6_clock_ops = {
 	.enable = cpg_div6_clock_enable,
 	.disable = cpg_div6_clock_disable,
 	.is_enabled = cpg_div6_clock_is_enabled,
 	.get_parent = cpg_div6_clock_get_parent,
 	.set_parent = cpg_div6_clock_set_parent,
 	.recalc_rate = cpg_div6_clock_recalc_rate,
 	.round_rate = cpg_div6_clock_round_rate,
 	.set_rate = cpg_div6_clock_set_rate,
 };

 static int cpg_div6_clock_notifier_call(struct notifier_block *nb,
 					unsigned long action, void *data)
 {
 	struct div6_clock *clock = container_of(nb, struct div6_clock, nb);

 	switch (action) {
 	case PM_EVENT_RESUME:
 		/*
 		 * TODO: This does not yet support DIV6 clocks with multiple
 		 * parents, as the parent selection bits are not restored.
 		 * Fortunately so far such DIV6 clocks are found only on
 		 * R/SH-Mobile SoCs, while the resume functionality is only
 		 * needed on R-Car Gen3.
 		 */
 		if (__clk_get_enable_count(clock->hw.clk))
 			cpg_div6_clock_enable(&clock->hw);
 		else
 			cpg_div6_clock_disable(&clock->hw);
 		return NOTIFY_OK;
 	}

 	return NOTIFY_DONE;
 }

 /**
  * cpg_div6_register - Register a DIV6 clock
  * @name: Name of the DIV6 clock
  * @num_parents: Number of parent clocks of the DIV6 clock (1, 4, or 8)
  * @parent_names: Array containing the names of the parent clocks
  * @reg: Mapped register used to control the DIV6 clock
  * @notifiers: Optional notifier chain to save/restore state for system resume
  */
 struct clk * __init cpg_div6_register(const char *name,
 				      unsigned int num_parents,
 				      const char **parent_names,
 				      void __iomem *reg,
 				      struct raw_notifier_head *notifiers)
 {
 	unsigned int valid_parents;
 	struct clk_init_data init;
 	struct div6_clock *clock;
 	struct clk *clk;
 	unsigned int i;

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

 	clock->parents = kmalloc_array(num_parents, sizeof(*clock->parents),
 				       GFP_KERNEL);
 	if (!clock->parents) {
 		clk = ERR_PTR(-ENOMEM);
 		goto free_clock;
 	}

 	clock->reg = reg;

 	/*
 	 * Read the divisor. Disabling the clock overwrites the divisor, so we
 	 * need to cache its value for the enable operation.
 	 */
 	clock->div = (readl(clock->reg) & CPG_DIV6_DIV_MASK) + 1;

 	switch (num_parents) {
 	case 1:
 		/* fixed parent clock */
 		clock->src_shift = clock->src_width = 0;
 		break;
 	case 4:
 		/* clock with EXSRC bits 6-7 */
 		clock->src_shift = 6;
 		clock->src_width = 2;
 		break;
 	case 8:
 		/* VCLK with EXSRC bits 12-14 */
 		clock->src_shift = 12;
 		clock->src_width = 3;
 		break;
 	default:
 		pr_err("%s: invalid number of parents for DIV6 clock %s\n",
 		       __func__, name);
 		clk = ERR_PTR(-EINVAL);
 		goto free_parents;
 	}

 	/* Filter out invalid parents */
 	for (i = 0, valid_parents = 0; i < num_parents; i++) {
 		if (parent_names[i]) {
 			parent_names[valid_parents] = parent_names[i];
 			clock->parents[valid_parents] = i;
 			valid_parents++;
 		}
 	}

 	/* Register the clock. */
 	init.name = name;
 	init.ops = &cpg_div6_clock_ops;
 	init.flags = 0;
 	init.parent_names = parent_names;
 	init.num_parents = valid_parents;

 	clock->hw.init = &init;

 	clk = clk_register(NULL, &clock->hw);
 	if (IS_ERR(clk))
 		goto free_parents;

 	if (notifiers) {
 		clock->nb.notifier_call = cpg_div6_clock_notifier_call;
 		raw_notifier_chain_register(notifiers, &clock->nb);
 	}

 	return clk;

 free_parents:
 	kfree(clock->parents);
 free_clock:
 	kfree(clock);
 	return clk;
 }

 static void __init cpg_div6_clock_init(struct device_node *np)
 {
 	unsigned int num_parents;
 	const char **parent_names;
 	const char *clk_name = np->name;
 	void __iomem *reg;
 	struct clk *clk;
 	unsigned int i;

 	num_parents = of_clk_get_parent_count(np);
 	if (num_parents < 1) {
 		pr_err("%s: no parent found for %pOFn DIV6 clock\n",
 		       __func__, np);
 		return;
 	}

 	parent_names = kmalloc_array(num_parents, sizeof(*parent_names),
 				GFP_KERNEL);
 	if (!parent_names)
 		return;

 	reg = of_iomap(np, 0);
 	if (reg == NULL) {
 		pr_err("%s: failed to map %pOFn DIV6 clock register\n",
 		       __func__, np);
 		goto error;
 	}

 	/* Parse the DT properties. */
 	of_property_read_string(np, "clock-output-names", &clk_name);

 	for (i = 0; i < num_parents; i++)
 		parent_names[i] = of_clk_get_parent_name(np, i);

 	clk = cpg_div6_register(clk_name, num_parents, parent_names, reg, NULL);
 	if (IS_ERR(clk)) {
 		pr_err("%s: failed to register %pOFn DIV6 clock (%ld)\n",
 		       __func__, np, PTR_ERR(clk));
 		goto error;
 	}

 	of_clk_add_provider(np, of_clk_src_simple_get, clk);

 	kfree(parent_names);
 	return;

 error:
 	if (reg)
 		iounmap(reg);
 	kfree(parent_names);
 }
 CLK_OF_DECLARE(cpg_div6_clk, "renesas,cpg-div6-clock", cpg_div6_clock_init);
	// SPDX-License-Identifier: GPL-2.0
	/*
	* r8a7790 Common Clock Framework support
	*
	* Copyright (C) 2013 Renesas Solutions Corp.
	*
	* Contact: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
	*/

	#include <linux/clk-provider.h>
	#include <linux/init.h>
	#include <linux/io.h>
	#include <linux/kernel.h>
	#include <linux/notifier.h>
	#include <linux/of.h>
	#include <linux/of_address.h>
	#include <linux/pm.h>
	#include <linux/slab.h>

	#include "clk-div6.h"

	#define CPG_DIV6_CKSTP BIT(8)
	#define CPG_DIV6_DIV(d) ((d) & 0x3f)
	#define CPG_DIV6_DIV_MASK 0x3f

	/**
	* struct div6_clock - CPG 6 bit divider clock
	* @hw: handle between common and hardware-specific interfaces
	* @reg: IO-remapped register
	* @div: divisor value (1-64)
	* @src_shift: Shift to access the register bits to select the parent clock
	* @src_width: Number of register bits to select the parent clock (may be 0)
	* @parents: Array to map from valid parent clocks indices to hardware indices
	* @nb: Notifier block to save/restore clock state for system resume
	*/
	struct div6_clock {
	struct clk_hw hw;
	void __iomem *reg;
	unsigned int div;
	u32 src_shift;
	u32 src_width;
	u8 *parents;
	struct notifier_block nb;
	};

	#define to_div6_clock(_hw) container_of(_hw, struct div6_clock, hw)

	static int cpg_div6_clock_enable(struct clk_hw *hw)
	{
	struct div6_clock *clock = to_div6_clock(hw);
	u32 val;

	val = (readl(clock->reg) & ~(CPG_DIV6_DIV_MASK \| CPG_DIV6_CKSTP))
	\| CPG_DIV6_DIV(clock->div - 1);
	writel(val, clock->reg);

	return 0;
	}

	static void cpg_div6_clock_disable(struct clk_hw *hw)
	{
	struct div6_clock *clock = to_div6_clock(hw);
	u32 val;

	val = readl(clock->reg);
	val \|= CPG_DIV6_CKSTP;
	/*
	* DIV6 clocks require the divisor field to be non-zero when stopping
	* the clock. However, some clocks (e.g. ZB on sh73a0) fail to be
	* re-enabled later if the divisor field is changed when stopping the
	* clock
	*/
	if (!(val & CPG_DIV6_DIV_MASK))
	val \|= CPG_DIV6_DIV_MASK;
	writel(val, clock->reg);
	}

	static int cpg_div6_clock_is_enabled(struct clk_hw *hw)
	{
	struct div6_clock *clock = to_div6_clock(hw);

	return !(readl(clock->reg) & CPG_DIV6_CKSTP);
	}

	static unsigned long cpg_div6_clock_recalc_rate(struct clk_hw *hw,
	unsigned long parent_rate)
	{
	struct div6_clock *clock = to_div6_clock(hw);

	return parent_rate / clock->div;
	}

	static unsigned int cpg_div6_clock_calc_div(unsigned long rate,
	unsigned long parent_rate)
	{
	unsigned int div;

	if (!rate)
	rate = 1;

	div = DIV_ROUND_CLOSEST(parent_rate, rate);
	return clamp_t(unsigned int, div, 1, 64);
	}

	static long cpg_div6_clock_round_rate(struct clk_hw *hw, unsigned long rate,
	unsigned long *parent_rate)
	{
	unsigned int div = cpg_div6_clock_calc_div(rate, *parent_rate);

	return *parent_rate / div;
	}

	static int cpg_div6_clock_set_rate(struct clk_hw *hw, unsigned long rate,
	unsigned long parent_rate)
	{
	struct div6_clock *clock = to_div6_clock(hw);
	unsigned int div = cpg_div6_clock_calc_div(rate, parent_rate);
	u32 val;

	clock->div = div;

	val = readl(clock->reg) & ~CPG_DIV6_DIV_MASK;
	/* Only program the new divisor if the clock isn't stopped. */
	if (!(val & CPG_DIV6_CKSTP))
	writel(val \| CPG_DIV6_DIV(clock->div - 1), clock->reg);

	return 0;
	}

	static u8 cpg_div6_clock_get_parent(struct clk_hw *hw)
	{
	struct div6_clock *clock = to_div6_clock(hw);
	unsigned int i;
	u8 hw_index;

	if (clock->src_width == 0)
	return 0;

	hw_index = (readl(clock->reg) >> clock->src_shift) &
	(BIT(clock->src_width) - 1);
	for (i = 0; i < clk_hw_get_num_parents(hw); i++) {
	if (clock->parents[i] == hw_index)
	return i;
	}

	pr_err("%s: %s DIV6 clock set to invalid parent %u\n",
	__func__, clk_hw_get_name(hw), hw_index);
	return 0;
	}

	static int cpg_div6_clock_set_parent(struct clk_hw *hw, u8 index)
	{
	struct div6_clock *clock = to_div6_clock(hw);
	u8 hw_index;
	u32 mask;

	if (index >= clk_hw_get_num_parents(hw))
	return -EINVAL;

	mask = ~((BIT(clock->src_width) - 1) << clock->src_shift);
	hw_index = clock->parents[index];

	writel((readl(clock->reg) & mask) \| (hw_index << clock->src_shift),
	clock->reg);

	return 0;
	}

	static const struct clk_ops cpg_div6_clock_ops = {
	.enable = cpg_div6_clock_enable,
	.disable = cpg_div6_clock_disable,
	.is_enabled = cpg_div6_clock_is_enabled,
	.get_parent = cpg_div6_clock_get_parent,
	.set_parent = cpg_div6_clock_set_parent,
	.recalc_rate = cpg_div6_clock_recalc_rate,
	.round_rate = cpg_div6_clock_round_rate,
	.set_rate = cpg_div6_clock_set_rate,
	};

	static int cpg_div6_clock_notifier_call(struct notifier_block *nb,
	unsigned long action, void *data)
	{
	struct div6_clock *clock = container_of(nb, struct div6_clock, nb);

	switch (action) {
	case PM_EVENT_RESUME:
	/*
	* TODO: This does not yet support DIV6 clocks with multiple
	* parents, as the parent selection bits are not restored.
	* Fortunately so far such DIV6 clocks are found only on
	* R/SH-Mobile SoCs, while the resume functionality is only
	* needed on R-Car Gen3.
	*/
	if (__clk_get_enable_count(clock->hw.clk))
	cpg_div6_clock_enable(&clock->hw);
	else
	cpg_div6_clock_disable(&clock->hw);
	return NOTIFY_OK;
	}

	return NOTIFY_DONE;
	}

	/**
	* cpg_div6_register - Register a DIV6 clock
	* @name: Name of the DIV6 clock
	* @num_parents: Number of parent clocks of the DIV6 clock (1, 4, or 8)
	* @parent_names: Array containing the names of the parent clocks
	* @reg: Mapped register used to control the DIV6 clock
	* @notifiers: Optional notifier chain to save/restore state for system resume
	*/
	struct clk * __init cpg_div6_register(const char *name,
	unsigned int num_parents,
	const char **parent_names,
	void __iomem *reg,
	struct raw_notifier_head *notifiers)
	{
	unsigned int valid_parents;
	struct clk_init_data init;
	struct div6_clock *clock;
	struct clk *clk;
	unsigned int i;

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

	clock->parents = kmalloc_array(num_parents, sizeof(*clock->parents),
	GFP_KERNEL);
	if (!clock->parents) {
	clk = ERR_PTR(-ENOMEM);
	goto free_clock;
	}

	clock->reg = reg;

	/*
	* Read the divisor. Disabling the clock overwrites the divisor, so we
	* need to cache its value for the enable operation.
	*/
	clock->div = (readl(clock->reg) & CPG_DIV6_DIV_MASK) + 1;

	switch (num_parents) {
	case 1:
	/* fixed parent clock */
	clock->src_shift = clock->src_width = 0;
	break;
	case 4:
	/* clock with EXSRC bits 6-7 */
	clock->src_shift = 6;
	clock->src_width = 2;
	break;
	case 8:
	/* VCLK with EXSRC bits 12-14 */
	clock->src_shift = 12;
	clock->src_width = 3;
	break;
	default:
	pr_err("%s: invalid number of parents for DIV6 clock %s\n",
	__func__, name);
	clk = ERR_PTR(-EINVAL);
	goto free_parents;
	}

	/* Filter out invalid parents */
	for (i = 0, valid_parents = 0; i < num_parents; i++) {
	if (parent_names[i]) {
	parent_names[valid_parents] = parent_names[i];
	clock->parents[valid_parents] = i;
	valid_parents++;
	}
	}

	/* Register the clock. */
	init.name = name;
	init.ops = &cpg_div6_clock_ops;
	init.flags = 0;
	init.parent_names = parent_names;
	init.num_parents = valid_parents;

	clock->hw.init = &init;

	clk = clk_register(NULL, &clock->hw);
	if (IS_ERR(clk))
	goto free_parents;

	if (notifiers) {
	clock->nb.notifier_call = cpg_div6_clock_notifier_call;
	raw_notifier_chain_register(notifiers, &clock->nb);
	}

	return clk;

	free_parents:
	kfree(clock->parents);
	free_clock:
	kfree(clock);
	return clk;
	}

	static void __init cpg_div6_clock_init(struct device_node *np)
	{
	unsigned int num_parents;
	const char **parent_names;
	const char *clk_name = np->name;
	void __iomem *reg;
	struct clk *clk;
	unsigned int i;

	num_parents = of_clk_get_parent_count(np);
	if (num_parents < 1) {
	pr_err("%s: no parent found for %pOFn DIV6 clock\n",
	__func__, np);
	return;
	}

	parent_names = kmalloc_array(num_parents, sizeof(*parent_names),
	GFP_KERNEL);
	if (!parent_names)
	return;

	reg = of_iomap(np, 0);
	if (reg == NULL) {
	pr_err("%s: failed to map %pOFn DIV6 clock register\n",
	__func__, np);
	goto error;
	}

	/* Parse the DT properties. */
	of_property_read_string(np, "clock-output-names", &clk_name);

	for (i = 0; i < num_parents; i++)
	parent_names[i] = of_clk_get_parent_name(np, i);

	clk = cpg_div6_register(clk_name, num_parents, parent_names, reg, NULL);
	if (IS_ERR(clk)) {
	pr_err("%s: failed to register %pOFn DIV6 clock (%ld)\n",
	__func__, np, PTR_ERR(clk));
	goto error;
	}

	of_clk_add_provider(np, of_clk_src_simple_get, clk);

	kfree(parent_names);
	return;

	error:
	if (reg)
	iounmap(reg);
	kfree(parent_names);
	}
	CLK_OF_DECLARE(cpg_div6_clk, "renesas,cpg-div6-clock", cpg_div6_clock_init);