drivers/clk/clk-plldig.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0
 /*
  * Copyright 2019 NXP
  *
  * Clock driver for LS1028A Display output interfaces(LCD, DPHY).
  */

 #include <linux/clk-provider.h>
 #include <linux/device.h>
 #include <linux/module.h>
 #include <linux/err.h>
 #include <linux/io.h>
 #include <linux/iopoll.h>
 #include <linux/of.h>
 #include <linux/of_address.h>
 #include <linux/of_device.h>
 #include <linux/platform_device.h>
 #include <linux/slab.h>
 #include <linux/bitfield.h>

 /* PLLDIG register offsets and bit masks */
 #define PLLDIG_REG_PLLSR            0x24
 #define PLLDIG_LOCK_MASK            BIT(2)
 #define PLLDIG_REG_PLLDV            0x28
 #define PLLDIG_MFD_MASK             GENMASK(7, 0)
 #define PLLDIG_RFDPHI1_MASK         GENMASK(30, 25)
 #define PLLDIG_REG_PLLFM            0x2c
 #define PLLDIG_SSCGBYP_ENABLE       BIT(30)
 #define PLLDIG_REG_PLLFD            0x30
 #define PLLDIG_FDEN                 BIT(30)
 #define PLLDIG_FRAC_MASK            GENMASK(15, 0)
 #define PLLDIG_REG_PLLCAL1          0x38
 #define PLLDIG_REG_PLLCAL2          0x3c

 /* Range of the VCO frequencies, in Hz */
 #define PLLDIG_MIN_VCO_FREQ         650000000
 #define PLLDIG_MAX_VCO_FREQ         1300000000

 /* Range of the output frequencies, in Hz */
 #define PHI1_MIN_FREQ               27000000UL
 #define PHI1_MAX_FREQ               600000000UL

 /* Maximum value of the reduced frequency divider */
 #define MAX_RFDPHI1          63UL

 /* Best value of multiplication factor divider */
 #define PLLDIG_DEFAULT_MFD   44

 /*
  * Denominator part of the fractional part of the
  * loop multiplication factor.
  */
 #define MFDEN          20480

 static const struct clk_parent_data parent_data[] = {
 	{ .index = 0 },
 };

 struct clk_plldig {
 	struct clk_hw hw;
 	void __iomem *regs;
 	unsigned int vco_freq;
 };

 #define to_clk_plldig(_hw)	container_of(_hw, struct clk_plldig, hw)

 static int plldig_enable(struct clk_hw *hw)
 {
 	struct clk_plldig *data = to_clk_plldig(hw);
 	u32 val;

 	val = readl(data->regs + PLLDIG_REG_PLLFM);
 	/*
 	 * Use Bypass mode with PLL off by default, the frequency overshoot
 	 * detector output was disable. SSCG Bypass mode should be enable.
 	 */
 	val |= PLLDIG_SSCGBYP_ENABLE;
 	writel(val, data->regs + PLLDIG_REG_PLLFM);

 	return 0;
 }

 static void plldig_disable(struct clk_hw *hw)
 {
 	struct clk_plldig *data = to_clk_plldig(hw);
 	u32 val;

 	val = readl(data->regs + PLLDIG_REG_PLLFM);

 	val &= ~PLLDIG_SSCGBYP_ENABLE;
 	val |= FIELD_PREP(PLLDIG_SSCGBYP_ENABLE, 0x0);

 	writel(val, data->regs + PLLDIG_REG_PLLFM);
 }

 static int plldig_is_enabled(struct clk_hw *hw)
 {
 	struct clk_plldig *data = to_clk_plldig(hw);

 	return readl(data->regs + PLLDIG_REG_PLLFM) &
 			      PLLDIG_SSCGBYP_ENABLE;
 }

 static unsigned long plldig_recalc_rate(struct clk_hw *hw,
 					unsigned long parent_rate)
 {
 	struct clk_plldig *data = to_clk_plldig(hw);
 	u32 val, rfdphi1;

 	val = readl(data->regs + PLLDIG_REG_PLLDV);

 	/* Check if PLL is bypassed */
 	if (val & PLLDIG_SSCGBYP_ENABLE)
 		return parent_rate;

 	rfdphi1 = FIELD_GET(PLLDIG_RFDPHI1_MASK, val);

 	/*
 	 * If RFDPHI1 has a value of 1 the VCO frequency is also divided by
 	 * one.
 	 */
 	if (!rfdphi1)
 		rfdphi1 = 1;

 	return DIV_ROUND_UP(data->vco_freq, rfdphi1);
 }

 static unsigned long plldig_calc_target_div(unsigned long vco_freq,
 					    unsigned long target_rate)
 {
 	unsigned long div;

 	div = DIV_ROUND_CLOSEST(vco_freq, target_rate);
 	div = clamp(div, 1UL, MAX_RFDPHI1);

 	return div;
 }

 static int plldig_determine_rate(struct clk_hw *hw,
 				 struct clk_rate_request *req)
 {
 	struct clk_plldig *data = to_clk_plldig(hw);
 	unsigned int div;

 	req->rate = clamp(req->rate, PHI1_MIN_FREQ, PHI1_MAX_FREQ);
 	div = plldig_calc_target_div(data->vco_freq, req->rate);
 	req->rate = DIV_ROUND_UP(data->vco_freq, div);

 	return 0;
 }

 static int plldig_set_rate(struct clk_hw *hw, unsigned long rate,
 		unsigned long parent_rate)
 {
 	struct clk_plldig *data = to_clk_plldig(hw);
 	unsigned int val, cond;
 	unsigned int rfdphi1;

 	rate = clamp(rate, PHI1_MIN_FREQ, PHI1_MAX_FREQ);
 	rfdphi1 = plldig_calc_target_div(data->vco_freq, rate);

 	/* update the divider value */
 	val = readl(data->regs + PLLDIG_REG_PLLDV);
 	val &= ~PLLDIG_RFDPHI1_MASK;
 	val |= FIELD_PREP(PLLDIG_RFDPHI1_MASK, rfdphi1);
 	writel(val, data->regs + PLLDIG_REG_PLLDV);

 	/* waiting for old lock state to clear */
 	udelay(200);

 	/* Wait until PLL is locked or timeout */
 	return readl_poll_timeout_atomic(data->regs + PLLDIG_REG_PLLSR, cond,
 					 cond & PLLDIG_LOCK_MASK, 0,
 					 USEC_PER_MSEC);
 }

 static const struct clk_ops plldig_clk_ops = {
 	.enable = plldig_enable,
 	.disable = plldig_disable,
 	.is_enabled = plldig_is_enabled,
 	.recalc_rate = plldig_recalc_rate,
 	.determine_rate = plldig_determine_rate,
 	.set_rate = plldig_set_rate,
 };

 static int plldig_init(struct clk_hw *hw)
 {
 	struct clk_plldig *data = to_clk_plldig(hw);
 	struct clk_hw *parent = clk_hw_get_parent(hw);
 	unsigned long parent_rate;
 	unsigned long val;
 	unsigned long long lltmp;
 	unsigned int mfd, fracdiv = 0;

 	if (!parent)
 		return -EINVAL;

 	parent_rate = clk_hw_get_rate(parent);

 	if (data->vco_freq) {
 		mfd = data->vco_freq / parent_rate;
 		lltmp = data->vco_freq % parent_rate;
 		lltmp *= MFDEN;
 		do_div(lltmp, parent_rate);
 		fracdiv = lltmp;
 	} else {
 		mfd = PLLDIG_DEFAULT_MFD;
 		data->vco_freq = parent_rate * mfd;
 	}

 	val = FIELD_PREP(PLLDIG_MFD_MASK, mfd);
 	writel(val, data->regs + PLLDIG_REG_PLLDV);

 	/* Enable fractional divider */
 	if (fracdiv) {
 		val = FIELD_PREP(PLLDIG_FRAC_MASK, fracdiv);
 		val |= PLLDIG_FDEN;
 		writel(val, data->regs + PLLDIG_REG_PLLFD);
 	}

 	return 0;
 }

 static int plldig_clk_probe(struct platform_device *pdev)
 {
 	struct clk_plldig *data;
 	struct device *dev = &pdev->dev;
 	int ret;

 	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
 	if (!data)
 		return -ENOMEM;

 	data->regs = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(data->regs))
 		return PTR_ERR(data->regs);

 	data->hw.init = CLK_HW_INIT_PARENTS_DATA("dpclk",
 						 parent_data,
 						 &plldig_clk_ops,
 						 0);

 	ret = devm_clk_hw_register(dev, &data->hw);
 	if (ret) {
 		dev_err(dev, "failed to register %s clock\n",
 						dev->of_node->name);
 		return ret;
 	}

 	ret = devm_of_clk_add_hw_provider(dev, of_clk_hw_simple_get,
 					  &data->hw);
 	if (ret) {
 		dev_err(dev, "unable to add clk provider\n");
 		return ret;
 	}

 	/*
 	 * The frequency of the VCO cannot be changed during runtime.
 	 * Therefore, let the user specify a desired frequency.
 	 */
 	if (!of_property_read_u32(dev->of_node, "fsl,vco-hz",
 				  &data->vco_freq)) {
 		if (data->vco_freq < PLLDIG_MIN_VCO_FREQ ||
 		    data->vco_freq > PLLDIG_MAX_VCO_FREQ)
 			return -EINVAL;
 	}

 	return plldig_init(&data->hw);
 }

 static const struct of_device_id plldig_clk_id[] = {
 	{ .compatible = "fsl,ls1028a-plldig" },
 	{ }
 };
 MODULE_DEVICE_TABLE(of, plldig_clk_id);

 static struct platform_driver plldig_clk_driver = {
 	.driver = {
 		.name = "plldig-clock",
 		.of_match_table = plldig_clk_id,
 	},
 	.probe = plldig_clk_probe,
 };
 module_platform_driver(plldig_clk_driver);

 MODULE_LICENSE("GPL v2");
 MODULE_AUTHOR("Wen He <wen.he_1@nxp.com>");
 MODULE_DESCRIPTION("LS1028A Display output interface pixel clock driver");
	// SPDX-License-Identifier: GPL-2.0
	/*
	* Copyright 2019 NXP
	*
	* Clock driver for LS1028A Display output interfaces(LCD, DPHY).
	*/

	#include <linux/clk-provider.h>
	#include <linux/device.h>
	#include <linux/module.h>
	#include <linux/err.h>
	#include <linux/io.h>
	#include <linux/iopoll.h>
	#include <linux/of.h>
	#include <linux/of_address.h>
	#include <linux/of_device.h>
	#include <linux/platform_device.h>
	#include <linux/slab.h>
	#include <linux/bitfield.h>

	/* PLLDIG register offsets and bit masks */
	#define PLLDIG_REG_PLLSR 0x24
	#define PLLDIG_LOCK_MASK BIT(2)
	#define PLLDIG_REG_PLLDV 0x28
	#define PLLDIG_MFD_MASK GENMASK(7, 0)
	#define PLLDIG_RFDPHI1_MASK GENMASK(30, 25)
	#define PLLDIG_REG_PLLFM 0x2c
	#define PLLDIG_SSCGBYP_ENABLE BIT(30)
	#define PLLDIG_REG_PLLFD 0x30
	#define PLLDIG_FDEN BIT(30)
	#define PLLDIG_FRAC_MASK GENMASK(15, 0)
	#define PLLDIG_REG_PLLCAL1 0x38
	#define PLLDIG_REG_PLLCAL2 0x3c

	/* Range of the VCO frequencies, in Hz */
	#define PLLDIG_MIN_VCO_FREQ 650000000
	#define PLLDIG_MAX_VCO_FREQ 1300000000

	/* Range of the output frequencies, in Hz */
	#define PHI1_MIN_FREQ 27000000UL
	#define PHI1_MAX_FREQ 600000000UL

	/* Maximum value of the reduced frequency divider */
	#define MAX_RFDPHI1 63UL

	/* Best value of multiplication factor divider */
	#define PLLDIG_DEFAULT_MFD 44

	/*
	* Denominator part of the fractional part of the
	* loop multiplication factor.
	*/
	#define MFDEN 20480

	static const struct clk_parent_data parent_data[] = {
	{ .index = 0 },
	};

	struct clk_plldig {
	struct clk_hw hw;
	void __iomem *regs;
	unsigned int vco_freq;
	};

	#define to_clk_plldig(_hw) container_of(_hw, struct clk_plldig, hw)

	static int plldig_enable(struct clk_hw *hw)
	{
	struct clk_plldig *data = to_clk_plldig(hw);
	u32 val;

	val = readl(data->regs + PLLDIG_REG_PLLFM);
	/*
	* Use Bypass mode with PLL off by default, the frequency overshoot
	* detector output was disable. SSCG Bypass mode should be enable.
	*/
	val \|= PLLDIG_SSCGBYP_ENABLE;
	writel(val, data->regs + PLLDIG_REG_PLLFM);

	return 0;
	}

	static void plldig_disable(struct clk_hw *hw)
	{
	struct clk_plldig *data = to_clk_plldig(hw);
	u32 val;

	val = readl(data->regs + PLLDIG_REG_PLLFM);

	val &= ~PLLDIG_SSCGBYP_ENABLE;
	val \|= FIELD_PREP(PLLDIG_SSCGBYP_ENABLE, 0x0);

	writel(val, data->regs + PLLDIG_REG_PLLFM);
	}

	static int plldig_is_enabled(struct clk_hw *hw)
	{
	struct clk_plldig *data = to_clk_plldig(hw);

	return readl(data->regs + PLLDIG_REG_PLLFM) &
	PLLDIG_SSCGBYP_ENABLE;
	}

	static unsigned long plldig_recalc_rate(struct clk_hw *hw,
	unsigned long parent_rate)
	{
	struct clk_plldig *data = to_clk_plldig(hw);
	u32 val, rfdphi1;

	val = readl(data->regs + PLLDIG_REG_PLLDV);

	/* Check if PLL is bypassed */
	if (val & PLLDIG_SSCGBYP_ENABLE)
	return parent_rate;

	rfdphi1 = FIELD_GET(PLLDIG_RFDPHI1_MASK, val);

	/*
	* If RFDPHI1 has a value of 1 the VCO frequency is also divided by
	* one.
	*/
	if (!rfdphi1)
	rfdphi1 = 1;

	return DIV_ROUND_UP(data->vco_freq, rfdphi1);
	}

	static unsigned long plldig_calc_target_div(unsigned long vco_freq,
	unsigned long target_rate)
	{
	unsigned long div;

	div = DIV_ROUND_CLOSEST(vco_freq, target_rate);
	div = clamp(div, 1UL, MAX_RFDPHI1);

	return div;
	}

	static int plldig_determine_rate(struct clk_hw *hw,
	struct clk_rate_request *req)
	{
	struct clk_plldig *data = to_clk_plldig(hw);
	unsigned int div;

	req->rate = clamp(req->rate, PHI1_MIN_FREQ, PHI1_MAX_FREQ);
	div = plldig_calc_target_div(data->vco_freq, req->rate);
	req->rate = DIV_ROUND_UP(data->vco_freq, div);

	return 0;
	}

	static int plldig_set_rate(struct clk_hw *hw, unsigned long rate,
	unsigned long parent_rate)
	{
	struct clk_plldig *data = to_clk_plldig(hw);
	unsigned int val, cond;
	unsigned int rfdphi1;

	rate = clamp(rate, PHI1_MIN_FREQ, PHI1_MAX_FREQ);
	rfdphi1 = plldig_calc_target_div(data->vco_freq, rate);

	/* update the divider value */
	val = readl(data->regs + PLLDIG_REG_PLLDV);
	val &= ~PLLDIG_RFDPHI1_MASK;
	val \|= FIELD_PREP(PLLDIG_RFDPHI1_MASK, rfdphi1);
	writel(val, data->regs + PLLDIG_REG_PLLDV);

	/* waiting for old lock state to clear */
	udelay(200);

	/* Wait until PLL is locked or timeout */
	return readl_poll_timeout_atomic(data->regs + PLLDIG_REG_PLLSR, cond,
	cond & PLLDIG_LOCK_MASK, 0,
	USEC_PER_MSEC);
	}

	static const struct clk_ops plldig_clk_ops = {
	.enable = plldig_enable,
	.disable = plldig_disable,
	.is_enabled = plldig_is_enabled,
	.recalc_rate = plldig_recalc_rate,
	.determine_rate = plldig_determine_rate,
	.set_rate = plldig_set_rate,
	};

	static int plldig_init(struct clk_hw *hw)
	{
	struct clk_plldig *data = to_clk_plldig(hw);
	struct clk_hw *parent = clk_hw_get_parent(hw);
	unsigned long parent_rate;
	unsigned long val;
	unsigned long long lltmp;
	unsigned int mfd, fracdiv = 0;

	if (!parent)
	return -EINVAL;

	parent_rate = clk_hw_get_rate(parent);

	if (data->vco_freq) {
	mfd = data->vco_freq / parent_rate;
	lltmp = data->vco_freq % parent_rate;
	lltmp *= MFDEN;
	do_div(lltmp, parent_rate);
	fracdiv = lltmp;
	} else {
	mfd = PLLDIG_DEFAULT_MFD;
	data->vco_freq = parent_rate * mfd;
	}

	val = FIELD_PREP(PLLDIG_MFD_MASK, mfd);
	writel(val, data->regs + PLLDIG_REG_PLLDV);

	/* Enable fractional divider */
	if (fracdiv) {
	val = FIELD_PREP(PLLDIG_FRAC_MASK, fracdiv);
	val \|= PLLDIG_FDEN;
	writel(val, data->regs + PLLDIG_REG_PLLFD);
	}

	return 0;
	}

	static int plldig_clk_probe(struct platform_device *pdev)
	{
	struct clk_plldig *data;
	struct device *dev = &pdev->dev;
	int ret;

	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
	if (!data)
	return -ENOMEM;

	data->regs = devm_platform_ioremap_resource(pdev, 0);
	if (IS_ERR(data->regs))
	return PTR_ERR(data->regs);

	data->hw.init = CLK_HW_INIT_PARENTS_DATA("dpclk",
	parent_data,
	&plldig_clk_ops,
	0);

	ret = devm_clk_hw_register(dev, &data->hw);
	if (ret) {
	dev_err(dev, "failed to register %s clock\n",
	dev->of_node->name);
	return ret;
	}

	ret = devm_of_clk_add_hw_provider(dev, of_clk_hw_simple_get,
	&data->hw);
	if (ret) {
	dev_err(dev, "unable to add clk provider\n");
	return ret;
	}

	/*
	* The frequency of the VCO cannot be changed during runtime.
	* Therefore, let the user specify a desired frequency.
	*/
	if (!of_property_read_u32(dev->of_node, "fsl,vco-hz",
	&data->vco_freq)) {
	if (data->vco_freq < PLLDIG_MIN_VCO_FREQ \|\|
	data->vco_freq > PLLDIG_MAX_VCO_FREQ)
	return -EINVAL;
	}

	return plldig_init(&data->hw);
	}

	static const struct of_device_id plldig_clk_id[] = {
	{ .compatible = "fsl,ls1028a-plldig" },
	{ }
	};
	MODULE_DEVICE_TABLE(of, plldig_clk_id);

	static struct platform_driver plldig_clk_driver = {
	.driver = {
	.name = "plldig-clock",
	.of_match_table = plldig_clk_id,
	},
	.probe = plldig_clk_probe,
	};
	module_platform_driver(plldig_clk_driver);

	MODULE_LICENSE("GPL v2");
	MODULE_AUTHOR("Wen He <wen.he_1@nxp.com>");
	MODULE_DESCRIPTION("LS1028A Display output interface pixel clock driver");