drivers/cpufreq/imx6q-cpufreq.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * Copyright (C) 2013 Freescale Semiconductor, Inc.
  */

 #include <linux/clk.h>
 #include <linux/cpu.h>
 #include <linux/cpufreq.h>
 #include <linux/err.h>
 #include <linux/module.h>
 #include <linux/nvmem-consumer.h>
 #include <linux/of.h>
 #include <linux/of_address.h>
 #include <linux/pm_opp.h>
 #include <linux/platform_device.h>
 #include <linux/regulator/consumer.h>
 #include <linux/mfd/syscon.h>
 #include <linux/regmap.h>

 #define PU_SOC_VOLTAGE_NORMAL	1250000
 #define PU_SOC_VOLTAGE_HIGH	1275000
 #define FREQ_1P2_GHZ		1200000000

 static struct regulator *arm_reg;
 static struct regulator *pu_reg;
 static struct regulator *soc_reg;

 enum IMX6_CPUFREQ_CLKS {
 	ARM,
 	PLL1_SYS,
 	STEP,
 	PLL1_SW,
 	PLL2_PFD2_396M,
 	/* MX6UL requires two more clks */
 	PLL2_BUS,
 	SECONDARY_SEL,
 };
 #define IMX6Q_CPUFREQ_CLK_NUM		5
 #define IMX6UL_CPUFREQ_CLK_NUM		7

 static int num_clks;
 static struct clk_bulk_data clks[] = {
 	{ .id = "arm" },
 	{ .id = "pll1_sys" },
 	{ .id = "step" },
 	{ .id = "pll1_sw" },
 	{ .id = "pll2_pfd2_396m" },
 	{ .id = "pll2_bus" },
 	{ .id = "secondary_sel" },
 };

 static struct device *cpu_dev;
 static struct cpufreq_frequency_table *freq_table;
 static unsigned int max_freq;
 static unsigned int transition_latency;

 static u32 *imx6_soc_volt;
 static u32 soc_opp_count;

 static int imx6q_set_target(struct cpufreq_policy *policy, unsigned int index)
 {
 	struct dev_pm_opp *opp;
 	unsigned long freq_hz, volt, volt_old;
 	unsigned int old_freq, new_freq;
 	bool pll1_sys_temp_enabled = false;
 	int ret;

 	new_freq = freq_table[index].frequency;
 	freq_hz = new_freq * 1000;
 	old_freq = clk_get_rate(clks[ARM].clk) / 1000;

 	opp = dev_pm_opp_find_freq_ceil(cpu_dev, &freq_hz);
 	if (IS_ERR(opp)) {
 		dev_err(cpu_dev, "failed to find OPP for %ld\n", freq_hz);
 		return PTR_ERR(opp);
 	}

 	volt = dev_pm_opp_get_voltage(opp);
 	dev_pm_opp_put(opp);

 	volt_old = regulator_get_voltage(arm_reg);

 	dev_dbg(cpu_dev, "%u MHz, %ld mV --> %u MHz, %ld mV\n",
 		old_freq / 1000, volt_old / 1000,
 		new_freq / 1000, volt / 1000);

 	/* scaling up?  scale voltage before frequency */
 	if (new_freq > old_freq) {
 		if (!IS_ERR(pu_reg)) {
 			ret = regulator_set_voltage_tol(pu_reg, imx6_soc_volt[index], 0);
 			if (ret) {
 				dev_err(cpu_dev, "failed to scale vddpu up: %d\n", ret);
 				return ret;
 			}
 		}
 		ret = regulator_set_voltage_tol(soc_reg, imx6_soc_volt[index], 0);
 		if (ret) {
 			dev_err(cpu_dev, "failed to scale vddsoc up: %d\n", ret);
 			return ret;
 		}
 		ret = regulator_set_voltage_tol(arm_reg, volt, 0);
 		if (ret) {
 			dev_err(cpu_dev,
 				"failed to scale vddarm up: %d\n", ret);
 			return ret;
 		}
 	}

 	/*
 	 * The setpoints are selected per PLL/PDF frequencies, so we need to
 	 * reprogram PLL for frequency scaling.  The procedure of reprogramming
 	 * PLL1 is as below.
 	 * For i.MX6UL, it has a secondary clk mux, the cpu frequency change
 	 * flow is slightly different from other i.MX6 OSC.
 	 * The cpu frequeny change flow for i.MX6(except i.MX6UL) is as below:
 	 *  - Enable pll2_pfd2_396m_clk and reparent pll1_sw_clk to it
 	 *  - Reprogram pll1_sys_clk and reparent pll1_sw_clk back to it
 	 *  - Disable pll2_pfd2_396m_clk
 	 */
 	if (of_machine_is_compatible("fsl,imx6ul") ||
 	    of_machine_is_compatible("fsl,imx6ull")) {
 		/*
 		 * When changing pll1_sw_clk's parent to pll1_sys_clk,
 		 * CPU may run at higher than 528MHz, this will lead to
 		 * the system unstable if the voltage is lower than the
 		 * voltage of 528MHz, so lower the CPU frequency to one
 		 * half before changing CPU frequency.
 		 */
 		clk_set_rate(clks[ARM].clk, (old_freq >> 1) * 1000);
 		clk_set_parent(clks[PLL1_SW].clk, clks[PLL1_SYS].clk);
 		if (freq_hz > clk_get_rate(clks[PLL2_PFD2_396M].clk))
 			clk_set_parent(clks[SECONDARY_SEL].clk,
 				       clks[PLL2_BUS].clk);
 		else
 			clk_set_parent(clks[SECONDARY_SEL].clk,
 				       clks[PLL2_PFD2_396M].clk);
 		clk_set_parent(clks[STEP].clk, clks[SECONDARY_SEL].clk);
 		clk_set_parent(clks[PLL1_SW].clk, clks[STEP].clk);
 		if (freq_hz > clk_get_rate(clks[PLL2_BUS].clk)) {
 			clk_set_rate(clks[PLL1_SYS].clk, new_freq * 1000);
 			clk_set_parent(clks[PLL1_SW].clk, clks[PLL1_SYS].clk);
 		}
 	} else {
 		clk_set_parent(clks[STEP].clk, clks[PLL2_PFD2_396M].clk);
 		clk_set_parent(clks[PLL1_SW].clk, clks[STEP].clk);
 		if (freq_hz > clk_get_rate(clks[PLL2_PFD2_396M].clk)) {
 			clk_set_rate(clks[PLL1_SYS].clk, new_freq * 1000);
 			clk_set_parent(clks[PLL1_SW].clk, clks[PLL1_SYS].clk);
 		} else {
 			/* pll1_sys needs to be enabled for divider rate change to work. */
 			pll1_sys_temp_enabled = true;
 			clk_prepare_enable(clks[PLL1_SYS].clk);
 		}
 	}

 	/* Ensure the arm clock divider is what we expect */
 	ret = clk_set_rate(clks[ARM].clk, new_freq * 1000);
 	if (ret) {
 		int ret1;

 		dev_err(cpu_dev, "failed to set clock rate: %d\n", ret);
 		ret1 = regulator_set_voltage_tol(arm_reg, volt_old, 0);
 		if (ret1)
 			dev_warn(cpu_dev,
 				 "failed to restore vddarm voltage: %d\n", ret1);
 		return ret;
 	}

 	/* PLL1 is only needed until after ARM-PODF is set. */
 	if (pll1_sys_temp_enabled)
 		clk_disable_unprepare(clks[PLL1_SYS].clk);

 	/* scaling down?  scale voltage after frequency */
 	if (new_freq < old_freq) {
 		ret = regulator_set_voltage_tol(arm_reg, volt, 0);
 		if (ret)
 			dev_warn(cpu_dev,
 				 "failed to scale vddarm down: %d\n", ret);
 		ret = regulator_set_voltage_tol(soc_reg, imx6_soc_volt[index], 0);
 		if (ret)
 			dev_warn(cpu_dev, "failed to scale vddsoc down: %d\n", ret);
 		if (!IS_ERR(pu_reg)) {
 			ret = regulator_set_voltage_tol(pu_reg, imx6_soc_volt[index], 0);
 			if (ret)
 				dev_warn(cpu_dev, "failed to scale vddpu down: %d\n", ret);
 		}
 	}

 	return 0;
 }

 static int imx6q_cpufreq_init(struct cpufreq_policy *policy)
 {
 	policy->clk = clks[ARM].clk;
 	cpufreq_generic_init(policy, freq_table, transition_latency);
 	policy->suspend_freq = max_freq;

 	return 0;
 }

 static struct cpufreq_driver imx6q_cpufreq_driver = {
 	.flags = CPUFREQ_NEED_INITIAL_FREQ_CHECK |
 		 CPUFREQ_IS_COOLING_DEV,
 	.verify = cpufreq_generic_frequency_table_verify,
 	.target_index = imx6q_set_target,
 	.get = cpufreq_generic_get,
 	.init = imx6q_cpufreq_init,
 	.register_em = cpufreq_register_em_with_opp,
 	.name = "imx6q-cpufreq",
 	.attr = cpufreq_generic_attr,
 	.suspend = cpufreq_generic_suspend,
 };

 static void imx6x_disable_freq_in_opp(struct device *dev, unsigned long freq)
 {
 	int ret = dev_pm_opp_disable(dev, freq);

 	if (ret < 0 && ret != -ENODEV)
 		dev_warn(dev, "failed to disable %ldMHz OPP\n", freq / 1000000);
 }

 #define OCOTP_CFG3			0x440
 #define OCOTP_CFG3_SPEED_SHIFT		16
 #define OCOTP_CFG3_SPEED_1P2GHZ		0x3
 #define OCOTP_CFG3_SPEED_996MHZ		0x2
 #define OCOTP_CFG3_SPEED_852MHZ		0x1

 static int imx6q_opp_check_speed_grading(struct device *dev)
 {
 	u32 val;
 	int ret;

 	if (of_property_present(dev->of_node, "nvmem-cells")) {
 		ret = nvmem_cell_read_u32(dev, "speed_grade", &val);
 		if (ret)
 			return ret;
 	} else {
 		struct regmap *ocotp;

 		ocotp = syscon_regmap_lookup_by_compatible("fsl,imx6q-ocotp");
 		if (IS_ERR(ocotp))
 			return -ENOENT;

 		/*
 		 * SPEED_GRADING[1:0] defines the max speed of ARM:
 		 * 2b'11: 1200000000Hz;
 		 * 2b'10: 996000000Hz;
 		 * 2b'01: 852000000Hz; -- i.MX6Q Only, exclusive with 996MHz.
 		 * 2b'00: 792000000Hz;
 		 * We need to set the max speed of ARM according to fuse map.
 		 */
 		regmap_read(ocotp, OCOTP_CFG3, &val);
 	}

 	val >>= OCOTP_CFG3_SPEED_SHIFT;
 	val &= 0x3;

 	if (val < OCOTP_CFG3_SPEED_996MHZ)
 		imx6x_disable_freq_in_opp(dev, 996000000);

 	if (of_machine_is_compatible("fsl,imx6q") ||
 	    of_machine_is_compatible("fsl,imx6qp")) {
 		if (val != OCOTP_CFG3_SPEED_852MHZ)
 			imx6x_disable_freq_in_opp(dev, 852000000);

 		if (val != OCOTP_CFG3_SPEED_1P2GHZ)
 			imx6x_disable_freq_in_opp(dev, 1200000000);
 	}

 	return 0;
 }

 #define OCOTP_CFG3_6UL_SPEED_696MHZ	0x2
 #define OCOTP_CFG3_6ULL_SPEED_792MHZ	0x2
 #define OCOTP_CFG3_6ULL_SPEED_900MHZ	0x3

 static int imx6ul_opp_check_speed_grading(struct device *dev)
 {
 	u32 val;
 	int ret = 0;

 	if (of_property_present(dev->of_node, "nvmem-cells")) {
 		ret = nvmem_cell_read_u32(dev, "speed_grade", &val);
 		if (ret)
 			return ret;
 	} else {
 		struct regmap *ocotp;

 		ocotp = syscon_regmap_lookup_by_compatible("fsl,imx6ul-ocotp");
 		if (IS_ERR(ocotp))
 			ocotp = syscon_regmap_lookup_by_compatible("fsl,imx6ull-ocotp");

 		if (IS_ERR(ocotp))
 			return -ENOENT;

 		regmap_read(ocotp, OCOTP_CFG3, &val);
 	}

 	/*
 	 * Speed GRADING[1:0] defines the max speed of ARM:
 	 * 2b'00: Reserved;
 	 * 2b'01: 528000000Hz;
 	 * 2b'10: 696000000Hz on i.MX6UL, 792000000Hz on i.MX6ULL;
 	 * 2b'11: 900000000Hz on i.MX6ULL only;
 	 * We need to set the max speed of ARM according to fuse map.
 	 */
 	val >>= OCOTP_CFG3_SPEED_SHIFT;
 	val &= 0x3;

 	if (of_machine_is_compatible("fsl,imx6ul"))
 		if (val != OCOTP_CFG3_6UL_SPEED_696MHZ)
 			imx6x_disable_freq_in_opp(dev, 696000000);

 	if (of_machine_is_compatible("fsl,imx6ull")) {
 		if (val < OCOTP_CFG3_6ULL_SPEED_792MHZ)
 			imx6x_disable_freq_in_opp(dev, 792000000);

 		if (val != OCOTP_CFG3_6ULL_SPEED_900MHZ)
 			imx6x_disable_freq_in_opp(dev, 900000000);
 	}

 	return ret;
 }

 static int imx6q_cpufreq_probe(struct platform_device *pdev)
 {
 	struct device_node *np;
 	struct dev_pm_opp *opp;
 	unsigned long min_volt, max_volt;
 	int num, ret;
 	const struct property *prop;
 	const __be32 *val;
 	u32 nr, i, j;

 	cpu_dev = get_cpu_device(0);
 	if (!cpu_dev) {
 		pr_err("failed to get cpu0 device\n");
 		return -ENODEV;
 	}

 	np = of_node_get(cpu_dev->of_node);
 	if (!np) {
 		dev_err(cpu_dev, "failed to find cpu0 node\n");
 		return -ENOENT;
 	}

 	if (of_machine_is_compatible("fsl,imx6ul") ||
 	    of_machine_is_compatible("fsl,imx6ull"))
 		num_clks = IMX6UL_CPUFREQ_CLK_NUM;
 	else
 		num_clks = IMX6Q_CPUFREQ_CLK_NUM;

 	ret = clk_bulk_get(cpu_dev, num_clks, clks);
 	if (ret)
 		goto put_node;

 	arm_reg = regulator_get(cpu_dev, "arm");
 	pu_reg = regulator_get_optional(cpu_dev, "pu");
 	soc_reg = regulator_get(cpu_dev, "soc");
 	if (PTR_ERR(arm_reg) == -EPROBE_DEFER ||
 			PTR_ERR(soc_reg) == -EPROBE_DEFER ||
 			PTR_ERR(pu_reg) == -EPROBE_DEFER) {
 		ret = -EPROBE_DEFER;
 		dev_dbg(cpu_dev, "regulators not ready, defer\n");
 		goto put_reg;
 	}
 	if (IS_ERR(arm_reg) || IS_ERR(soc_reg)) {
 		dev_err(cpu_dev, "failed to get regulators\n");
 		ret = -ENOENT;
 		goto put_reg;
 	}

 	ret = dev_pm_opp_of_add_table(cpu_dev);
 	if (ret < 0) {
 		dev_err(cpu_dev, "failed to init OPP table: %d\n", ret);
 		goto put_reg;
 	}

 	if (of_machine_is_compatible("fsl,imx6ul") ||
 	    of_machine_is_compatible("fsl,imx6ull")) {
 		ret = imx6ul_opp_check_speed_grading(cpu_dev);
 	} else {
 		ret = imx6q_opp_check_speed_grading(cpu_dev);
 	}
 	if (ret) {
 		dev_err_probe(cpu_dev, ret, "failed to read ocotp\n");
 		goto out_free_opp;
 	}

 	num = dev_pm_opp_get_opp_count(cpu_dev);
 	if (num < 0) {
 		ret = num;
 		dev_err(cpu_dev, "no OPP table is found: %d\n", ret);
 		goto out_free_opp;
 	}

 	ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &freq_table);
 	if (ret) {
 		dev_err(cpu_dev, "failed to init cpufreq table: %d\n", ret);
 		goto out_free_opp;
 	}

 	/* Make imx6_soc_volt array's size same as arm opp number */
 	imx6_soc_volt = devm_kcalloc(cpu_dev, num, sizeof(*imx6_soc_volt),
 				     GFP_KERNEL);
 	if (imx6_soc_volt == NULL) {
 		ret = -ENOMEM;
 		goto free_freq_table;
 	}

 	prop = of_find_property(np, "fsl,soc-operating-points", NULL);
 	if (!prop || !prop->value)
 		goto soc_opp_out;

 	/*
 	 * Each OPP is a set of tuples consisting of frequency and
 	 * voltage like <freq-kHz vol-uV>.
 	 */
 	nr = prop->length / sizeof(u32);
 	if (nr % 2 || (nr / 2) < num)
 		goto soc_opp_out;

 	for (j = 0; j < num; j++) {
 		val = prop->value;
 		for (i = 0; i < nr / 2; i++) {
 			unsigned long freq = be32_to_cpup(val++);
 			unsigned long volt = be32_to_cpup(val++);
 			if (freq_table[j].frequency == freq) {
 				imx6_soc_volt[soc_opp_count++] = volt;
 				break;
 			}
 		}
 	}

 soc_opp_out:
 	/* use fixed soc opp volt if no valid soc opp info found in dtb */
 	if (soc_opp_count != num) {
 		dev_warn(cpu_dev, "can NOT find valid fsl,soc-operating-points property in dtb, use default value!\n");
 		for (j = 0; j < num; j++)
 			imx6_soc_volt[j] = PU_SOC_VOLTAGE_NORMAL;
 		if (freq_table[num - 1].frequency * 1000 == FREQ_1P2_GHZ)
 			imx6_soc_volt[num - 1] = PU_SOC_VOLTAGE_HIGH;
 	}

 	if (of_property_read_u32(np, "clock-latency", &transition_latency))
 		transition_latency = CPUFREQ_ETERNAL;

 	/*
 	 * Calculate the ramp time for max voltage change in the
 	 * VDDSOC and VDDPU regulators.
 	 */
 	ret = regulator_set_voltage_time(soc_reg, imx6_soc_volt[0], imx6_soc_volt[num - 1]);
 	if (ret > 0)
 		transition_latency += ret * 1000;
 	if (!IS_ERR(pu_reg)) {
 		ret = regulator_set_voltage_time(pu_reg, imx6_soc_volt[0], imx6_soc_volt[num - 1]);
 		if (ret > 0)
 			transition_latency += ret * 1000;
 	}

 	/*
 	 * OPP is maintained in order of increasing frequency, and
 	 * freq_table initialised from OPP is therefore sorted in the
 	 * same order.
 	 */
 	max_freq = freq_table[--num].frequency;
 	opp = dev_pm_opp_find_freq_exact(cpu_dev,
 				  freq_table[0].frequency * 1000, true);
 	min_volt = dev_pm_opp_get_voltage(opp);
 	dev_pm_opp_put(opp);
 	opp = dev_pm_opp_find_freq_exact(cpu_dev, max_freq * 1000, true);
 	max_volt = dev_pm_opp_get_voltage(opp);
 	dev_pm_opp_put(opp);

 	ret = regulator_set_voltage_time(arm_reg, min_volt, max_volt);
 	if (ret > 0)
 		transition_latency += ret * 1000;

 	ret = cpufreq_register_driver(&imx6q_cpufreq_driver);
 	if (ret) {
 		dev_err(cpu_dev, "failed register driver: %d\n", ret);
 		goto free_freq_table;
 	}

 	of_node_put(np);
 	return 0;

 free_freq_table:
 	dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table);
 out_free_opp:
 	dev_pm_opp_of_remove_table(cpu_dev);
 put_reg:
 	if (!IS_ERR(arm_reg))
 		regulator_put(arm_reg);
 	if (!IS_ERR(pu_reg))
 		regulator_put(pu_reg);
 	if (!IS_ERR(soc_reg))
 		regulator_put(soc_reg);

 	clk_bulk_put(num_clks, clks);
 put_node:
 	of_node_put(np);

 	return ret;
 }

 static void imx6q_cpufreq_remove(struct platform_device *pdev)
 {
 	cpufreq_unregister_driver(&imx6q_cpufreq_driver);
 	dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table);
 	dev_pm_opp_of_remove_table(cpu_dev);
 	regulator_put(arm_reg);
 	if (!IS_ERR(pu_reg))
 		regulator_put(pu_reg);
 	regulator_put(soc_reg);

 	clk_bulk_put(num_clks, clks);
 }

 static struct platform_driver imx6q_cpufreq_platdrv = {
 	.driver = {
 		.name	= "imx6q-cpufreq",
 	},
 	.probe		= imx6q_cpufreq_probe,
 	.remove		= imx6q_cpufreq_remove,
 };
 module_platform_driver(imx6q_cpufreq_platdrv);

 MODULE_ALIAS("platform:imx6q-cpufreq");
 MODULE_AUTHOR("Shawn Guo <shawn.guo@linaro.org>");
 MODULE_DESCRIPTION("Freescale i.MX6Q cpufreq driver");
 MODULE_LICENSE("GPL");
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	* Copyright (C) 2013 Freescale Semiconductor, Inc.
	*/

	#include <linux/clk.h>
	#include <linux/cpu.h>
	#include <linux/cpufreq.h>
	#include <linux/err.h>
	#include <linux/module.h>
	#include <linux/nvmem-consumer.h>
	#include <linux/of.h>
	#include <linux/of_address.h>
	#include <linux/pm_opp.h>
	#include <linux/platform_device.h>
	#include <linux/regulator/consumer.h>
	#include <linux/mfd/syscon.h>
	#include <linux/regmap.h>

	#define PU_SOC_VOLTAGE_NORMAL 1250000
	#define PU_SOC_VOLTAGE_HIGH 1275000
	#define FREQ_1P2_GHZ 1200000000

	static struct regulator *arm_reg;
	static struct regulator *pu_reg;
	static struct regulator *soc_reg;

	enum IMX6_CPUFREQ_CLKS {
	ARM,
	PLL1_SYS,
	STEP,
	PLL1_SW,
	PLL2_PFD2_396M,
	/* MX6UL requires two more clks */
	PLL2_BUS,
	SECONDARY_SEL,
	};
	#define IMX6Q_CPUFREQ_CLK_NUM 5
	#define IMX6UL_CPUFREQ_CLK_NUM 7

	static int num_clks;
	static struct clk_bulk_data clks[] = {
	{ .id = "arm" },
	{ .id = "pll1_sys" },
	{ .id = "step" },
	{ .id = "pll1_sw" },
	{ .id = "pll2_pfd2_396m" },
	{ .id = "pll2_bus" },
	{ .id = "secondary_sel" },
	};

	static struct device *cpu_dev;
	static struct cpufreq_frequency_table *freq_table;
	static unsigned int max_freq;
	static unsigned int transition_latency;

	static u32 *imx6_soc_volt;
	static u32 soc_opp_count;

	static int imx6q_set_target(struct cpufreq_policy *policy, unsigned int index)
	{
	struct dev_pm_opp *opp;
	unsigned long freq_hz, volt, volt_old;
	unsigned int old_freq, new_freq;
	bool pll1_sys_temp_enabled = false;
	int ret;

	new_freq = freq_table[index].frequency;
	freq_hz = new_freq * 1000;
	old_freq = clk_get_rate(clks[ARM].clk) / 1000;

	opp = dev_pm_opp_find_freq_ceil(cpu_dev, &freq_hz);
	if (IS_ERR(opp)) {
	dev_err(cpu_dev, "failed to find OPP for %ld\n", freq_hz);
	return PTR_ERR(opp);
	}

	volt = dev_pm_opp_get_voltage(opp);
	dev_pm_opp_put(opp);

	volt_old = regulator_get_voltage(arm_reg);

	dev_dbg(cpu_dev, "%u MHz, %ld mV --> %u MHz, %ld mV\n",
	old_freq / 1000, volt_old / 1000,
	new_freq / 1000, volt / 1000);

	/* scaling up? scale voltage before frequency */
	if (new_freq > old_freq) {
	if (!IS_ERR(pu_reg)) {
	ret = regulator_set_voltage_tol(pu_reg, imx6_soc_volt[index], 0);
	if (ret) {
	dev_err(cpu_dev, "failed to scale vddpu up: %d\n", ret);
	return ret;
	}
	}
	ret = regulator_set_voltage_tol(soc_reg, imx6_soc_volt[index], 0);
	if (ret) {
	dev_err(cpu_dev, "failed to scale vddsoc up: %d\n", ret);
	return ret;
	}
	ret = regulator_set_voltage_tol(arm_reg, volt, 0);
	if (ret) {
	dev_err(cpu_dev,
	"failed to scale vddarm up: %d\n", ret);
	return ret;
	}
	}

	/*
	* The setpoints are selected per PLL/PDF frequencies, so we need to
	* reprogram PLL for frequency scaling. The procedure of reprogramming
	* PLL1 is as below.
	* For i.MX6UL, it has a secondary clk mux, the cpu frequency change
	* flow is slightly different from other i.MX6 OSC.
	* The cpu frequeny change flow for i.MX6(except i.MX6UL) is as below:
	* - Enable pll2_pfd2_396m_clk and reparent pll1_sw_clk to it
	* - Reprogram pll1_sys_clk and reparent pll1_sw_clk back to it
	* - Disable pll2_pfd2_396m_clk
	*/
	if (of_machine_is_compatible("fsl,imx6ul") \|\|
	of_machine_is_compatible("fsl,imx6ull")) {
	/*
	* When changing pll1_sw_clk's parent to pll1_sys_clk,
	* CPU may run at higher than 528MHz, this will lead to
	* the system unstable if the voltage is lower than the
	* voltage of 528MHz, so lower the CPU frequency to one
	* half before changing CPU frequency.
	*/
	clk_set_rate(clks[ARM].clk, (old_freq >> 1) * 1000);
	clk_set_parent(clks[PLL1_SW].clk, clks[PLL1_SYS].clk);
	if (freq_hz > clk_get_rate(clks[PLL2_PFD2_396M].clk))
	clk_set_parent(clks[SECONDARY_SEL].clk,
	clks[PLL2_BUS].clk);
	else
	clk_set_parent(clks[SECONDARY_SEL].clk,
	clks[PLL2_PFD2_396M].clk);
	clk_set_parent(clks[STEP].clk, clks[SECONDARY_SEL].clk);
	clk_set_parent(clks[PLL1_SW].clk, clks[STEP].clk);
	if (freq_hz > clk_get_rate(clks[PLL2_BUS].clk)) {
	clk_set_rate(clks[PLL1_SYS].clk, new_freq * 1000);
	clk_set_parent(clks[PLL1_SW].clk, clks[PLL1_SYS].clk);
	}
	} else {
	clk_set_parent(clks[STEP].clk, clks[PLL2_PFD2_396M].clk);
	clk_set_parent(clks[PLL1_SW].clk, clks[STEP].clk);
	if (freq_hz > clk_get_rate(clks[PLL2_PFD2_396M].clk)) {
	clk_set_rate(clks[PLL1_SYS].clk, new_freq * 1000);
	clk_set_parent(clks[PLL1_SW].clk, clks[PLL1_SYS].clk);
	} else {
	/* pll1_sys needs to be enabled for divider rate change to work. */
	pll1_sys_temp_enabled = true;
	clk_prepare_enable(clks[PLL1_SYS].clk);
	}
	}

	/* Ensure the arm clock divider is what we expect */
	ret = clk_set_rate(clks[ARM].clk, new_freq * 1000);
	if (ret) {
	int ret1;

	dev_err(cpu_dev, "failed to set clock rate: %d\n", ret);
	ret1 = regulator_set_voltage_tol(arm_reg, volt_old, 0);
	if (ret1)
	dev_warn(cpu_dev,
	"failed to restore vddarm voltage: %d\n", ret1);
	return ret;
	}

	/* PLL1 is only needed until after ARM-PODF is set. */
	if (pll1_sys_temp_enabled)
	clk_disable_unprepare(clks[PLL1_SYS].clk);

	/* scaling down? scale voltage after frequency */
	if (new_freq < old_freq) {
	ret = regulator_set_voltage_tol(arm_reg, volt, 0);
	if (ret)
	dev_warn(cpu_dev,
	"failed to scale vddarm down: %d\n", ret);
	ret = regulator_set_voltage_tol(soc_reg, imx6_soc_volt[index], 0);
	if (ret)
	dev_warn(cpu_dev, "failed to scale vddsoc down: %d\n", ret);
	if (!IS_ERR(pu_reg)) {
	ret = regulator_set_voltage_tol(pu_reg, imx6_soc_volt[index], 0);
	if (ret)
	dev_warn(cpu_dev, "failed to scale vddpu down: %d\n", ret);
	}
	}

	return 0;
	}

	static int imx6q_cpufreq_init(struct cpufreq_policy *policy)
	{
	policy->clk = clks[ARM].clk;
	cpufreq_generic_init(policy, freq_table, transition_latency);
	policy->suspend_freq = max_freq;

	return 0;
	}

	static struct cpufreq_driver imx6q_cpufreq_driver = {
	.flags = CPUFREQ_NEED_INITIAL_FREQ_CHECK \|
	CPUFREQ_IS_COOLING_DEV,
	.verify = cpufreq_generic_frequency_table_verify,
	.target_index = imx6q_set_target,
	.get = cpufreq_generic_get,
	.init = imx6q_cpufreq_init,
	.register_em = cpufreq_register_em_with_opp,
	.name = "imx6q-cpufreq",
	.attr = cpufreq_generic_attr,
	.suspend = cpufreq_generic_suspend,
	};

	static void imx6x_disable_freq_in_opp(struct device *dev, unsigned long freq)
	{
	int ret = dev_pm_opp_disable(dev, freq);

	if (ret < 0 && ret != -ENODEV)
	dev_warn(dev, "failed to disable %ldMHz OPP\n", freq / 1000000);
	}

	#define OCOTP_CFG3 0x440
	#define OCOTP_CFG3_SPEED_SHIFT 16
	#define OCOTP_CFG3_SPEED_1P2GHZ 0x3
	#define OCOTP_CFG3_SPEED_996MHZ 0x2
	#define OCOTP_CFG3_SPEED_852MHZ 0x1

	static int imx6q_opp_check_speed_grading(struct device *dev)
	{
	u32 val;
	int ret;

	if (of_property_present(dev->of_node, "nvmem-cells")) {
	ret = nvmem_cell_read_u32(dev, "speed_grade", &val);
	if (ret)
	return ret;
	} else {
	struct regmap *ocotp;

	ocotp = syscon_regmap_lookup_by_compatible("fsl,imx6q-ocotp");
	if (IS_ERR(ocotp))
	return -ENOENT;

	/*
	* SPEED_GRADING[1:0] defines the max speed of ARM:
	* 2b'11: 1200000000Hz;
	* 2b'10: 996000000Hz;
	* 2b'01: 852000000Hz; -- i.MX6Q Only, exclusive with 996MHz.
	* 2b'00: 792000000Hz;
	* We need to set the max speed of ARM according to fuse map.
	*/
	regmap_read(ocotp, OCOTP_CFG3, &val);
	}

	val >>= OCOTP_CFG3_SPEED_SHIFT;
	val &= 0x3;

	if (val < OCOTP_CFG3_SPEED_996MHZ)
	imx6x_disable_freq_in_opp(dev, 996000000);

	if (of_machine_is_compatible("fsl,imx6q") \|\|
	of_machine_is_compatible("fsl,imx6qp")) {
	if (val != OCOTP_CFG3_SPEED_852MHZ)
	imx6x_disable_freq_in_opp(dev, 852000000);

	if (val != OCOTP_CFG3_SPEED_1P2GHZ)
	imx6x_disable_freq_in_opp(dev, 1200000000);
	}

	return 0;
	}

	#define OCOTP_CFG3_6UL_SPEED_696MHZ 0x2
	#define OCOTP_CFG3_6ULL_SPEED_792MHZ 0x2
	#define OCOTP_CFG3_6ULL_SPEED_900MHZ 0x3

	static int imx6ul_opp_check_speed_grading(struct device *dev)
	{
	u32 val;
	int ret = 0;

	if (of_property_present(dev->of_node, "nvmem-cells")) {
	ret = nvmem_cell_read_u32(dev, "speed_grade", &val);
	if (ret)
	return ret;
	} else {
	struct regmap *ocotp;

	ocotp = syscon_regmap_lookup_by_compatible("fsl,imx6ul-ocotp");
	if (IS_ERR(ocotp))
	ocotp = syscon_regmap_lookup_by_compatible("fsl,imx6ull-ocotp");

	if (IS_ERR(ocotp))
	return -ENOENT;

	regmap_read(ocotp, OCOTP_CFG3, &val);
	}

	/*
	* Speed GRADING[1:0] defines the max speed of ARM:
	* 2b'00: Reserved;
	* 2b'01: 528000000Hz;
	* 2b'10: 696000000Hz on i.MX6UL, 792000000Hz on i.MX6ULL;
	* 2b'11: 900000000Hz on i.MX6ULL only;
	* We need to set the max speed of ARM according to fuse map.
	*/
	val >>= OCOTP_CFG3_SPEED_SHIFT;
	val &= 0x3;

	if (of_machine_is_compatible("fsl,imx6ul"))
	if (val != OCOTP_CFG3_6UL_SPEED_696MHZ)
	imx6x_disable_freq_in_opp(dev, 696000000);

	if (of_machine_is_compatible("fsl,imx6ull")) {
	if (val < OCOTP_CFG3_6ULL_SPEED_792MHZ)
	imx6x_disable_freq_in_opp(dev, 792000000);

	if (val != OCOTP_CFG3_6ULL_SPEED_900MHZ)
	imx6x_disable_freq_in_opp(dev, 900000000);
	}

	return ret;
	}

	static int imx6q_cpufreq_probe(struct platform_device *pdev)
	{
	struct device_node *np;
	struct dev_pm_opp *opp;
	unsigned long min_volt, max_volt;
	int num, ret;
	const struct property *prop;
	const __be32 *val;
	u32 nr, i, j;

	cpu_dev = get_cpu_device(0);
	if (!cpu_dev) {
	pr_err("failed to get cpu0 device\n");
	return -ENODEV;
	}

	np = of_node_get(cpu_dev->of_node);
	if (!np) {
	dev_err(cpu_dev, "failed to find cpu0 node\n");
	return -ENOENT;
	}

	if (of_machine_is_compatible("fsl,imx6ul") \|\|
	of_machine_is_compatible("fsl,imx6ull"))
	num_clks = IMX6UL_CPUFREQ_CLK_NUM;
	else
	num_clks = IMX6Q_CPUFREQ_CLK_NUM;

	ret = clk_bulk_get(cpu_dev, num_clks, clks);
	if (ret)
	goto put_node;

	arm_reg = regulator_get(cpu_dev, "arm");
	pu_reg = regulator_get_optional(cpu_dev, "pu");
	soc_reg = regulator_get(cpu_dev, "soc");
	if (PTR_ERR(arm_reg) == -EPROBE_DEFER \|\|
	PTR_ERR(soc_reg) == -EPROBE_DEFER \|\|
	PTR_ERR(pu_reg) == -EPROBE_DEFER) {
	ret = -EPROBE_DEFER;
	dev_dbg(cpu_dev, "regulators not ready, defer\n");
	goto put_reg;
	}
	if (IS_ERR(arm_reg) \|\| IS_ERR(soc_reg)) {
	dev_err(cpu_dev, "failed to get regulators\n");
	ret = -ENOENT;
	goto put_reg;
	}

	ret = dev_pm_opp_of_add_table(cpu_dev);
	if (ret < 0) {
	dev_err(cpu_dev, "failed to init OPP table: %d\n", ret);
	goto put_reg;
	}

	if (of_machine_is_compatible("fsl,imx6ul") \|\|
	of_machine_is_compatible("fsl,imx6ull")) {
	ret = imx6ul_opp_check_speed_grading(cpu_dev);
	} else {
	ret = imx6q_opp_check_speed_grading(cpu_dev);
	}
	if (ret) {
	dev_err_probe(cpu_dev, ret, "failed to read ocotp\n");
	goto out_free_opp;
	}

	num = dev_pm_opp_get_opp_count(cpu_dev);
	if (num < 0) {
	ret = num;
	dev_err(cpu_dev, "no OPP table is found: %d\n", ret);
	goto out_free_opp;
	}

	ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &freq_table);
	if (ret) {
	dev_err(cpu_dev, "failed to init cpufreq table: %d\n", ret);
	goto out_free_opp;
	}

	/* Make imx6_soc_volt array's size same as arm opp number */
	imx6_soc_volt = devm_kcalloc(cpu_dev, num, sizeof(*imx6_soc_volt),
	GFP_KERNEL);
	if (imx6_soc_volt == NULL) {
	ret = -ENOMEM;
	goto free_freq_table;
	}

	prop = of_find_property(np, "fsl,soc-operating-points", NULL);
	if (!prop \|\| !prop->value)
	goto soc_opp_out;

	/*
	* Each OPP is a set of tuples consisting of frequency and
	* voltage like <freq-kHz vol-uV>.
	*/
	nr = prop->length / sizeof(u32);
	if (nr % 2 \|\| (nr / 2) < num)
	goto soc_opp_out;

	for (j = 0; j < num; j++) {
	val = prop->value;
	for (i = 0; i < nr / 2; i++) {
	unsigned long freq = be32_to_cpup(val++);
	unsigned long volt = be32_to_cpup(val++);
	if (freq_table[j].frequency == freq) {
	imx6_soc_volt[soc_opp_count++] = volt;
	break;
	}
	}
	}

	soc_opp_out:
	/* use fixed soc opp volt if no valid soc opp info found in dtb */
	if (soc_opp_count != num) {
	dev_warn(cpu_dev, "can NOT find valid fsl,soc-operating-points property in dtb, use default value!\n");
	for (j = 0; j < num; j++)
	imx6_soc_volt[j] = PU_SOC_VOLTAGE_NORMAL;
	if (freq_table[num - 1].frequency * 1000 == FREQ_1P2_GHZ)
	imx6_soc_volt[num - 1] = PU_SOC_VOLTAGE_HIGH;
	}

	if (of_property_read_u32(np, "clock-latency", &transition_latency))
	transition_latency = CPUFREQ_ETERNAL;

	/*
	* Calculate the ramp time for max voltage change in the
	* VDDSOC and VDDPU regulators.
	*/
	ret = regulator_set_voltage_time(soc_reg, imx6_soc_volt[0], imx6_soc_volt[num - 1]);
	if (ret > 0)
	transition_latency += ret * 1000;
	if (!IS_ERR(pu_reg)) {
	ret = regulator_set_voltage_time(pu_reg, imx6_soc_volt[0], imx6_soc_volt[num - 1]);
	if (ret > 0)
	transition_latency += ret * 1000;
	}

	/*
	* OPP is maintained in order of increasing frequency, and
	* freq_table initialised from OPP is therefore sorted in the
	* same order.
	*/
	max_freq = freq_table[--num].frequency;
	opp = dev_pm_opp_find_freq_exact(cpu_dev,
	freq_table[0].frequency * 1000, true);
	min_volt = dev_pm_opp_get_voltage(opp);
	dev_pm_opp_put(opp);
	opp = dev_pm_opp_find_freq_exact(cpu_dev, max_freq * 1000, true);
	max_volt = dev_pm_opp_get_voltage(opp);
	dev_pm_opp_put(opp);

	ret = regulator_set_voltage_time(arm_reg, min_volt, max_volt);
	if (ret > 0)
	transition_latency += ret * 1000;

	ret = cpufreq_register_driver(&imx6q_cpufreq_driver);
	if (ret) {
	dev_err(cpu_dev, "failed register driver: %d\n", ret);
	goto free_freq_table;
	}

	of_node_put(np);
	return 0;

	free_freq_table:
	dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table);
	out_free_opp:
	dev_pm_opp_of_remove_table(cpu_dev);
	put_reg:
	if (!IS_ERR(arm_reg))
	regulator_put(arm_reg);
	if (!IS_ERR(pu_reg))
	regulator_put(pu_reg);
	if (!IS_ERR(soc_reg))
	regulator_put(soc_reg);

	clk_bulk_put(num_clks, clks);
	put_node:
	of_node_put(np);

	return ret;
	}

	static void imx6q_cpufreq_remove(struct platform_device *pdev)
	{
	cpufreq_unregister_driver(&imx6q_cpufreq_driver);
	dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table);
	dev_pm_opp_of_remove_table(cpu_dev);
	regulator_put(arm_reg);
	if (!IS_ERR(pu_reg))
	regulator_put(pu_reg);
	regulator_put(soc_reg);

	clk_bulk_put(num_clks, clks);
	}

	static struct platform_driver imx6q_cpufreq_platdrv = {
	.driver = {
	.name = "imx6q-cpufreq",
	},
	.probe = imx6q_cpufreq_probe,
	.remove = imx6q_cpufreq_remove,
	};
	module_platform_driver(imx6q_cpufreq_platdrv);

	MODULE_ALIAS("platform:imx6q-cpufreq");
	MODULE_AUTHOR("Shawn Guo <shawn.guo@linaro.org>");
	MODULE_DESCRIPTION("Freescale i.MX6Q cpufreq driver");
	MODULE_LICENSE("GPL");