drivers/soc/tegra/regulators-tegra30.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0+
 /*
  * Voltage regulators coupler for NVIDIA Tegra30
  * Copyright (C) 2019 GRATE-DRIVER project
  *
  * Voltage constraints borrowed from downstream kernel sources
  * Copyright (C) 2010-2011 NVIDIA Corporation
  */

 #define pr_fmt(fmt)	"tegra voltage-coupler: " fmt

 #include <linux/init.h>
 #include <linux/kernel.h>
 #include <linux/of.h>
 #include <linux/regulator/coupler.h>
 #include <linux/regulator/driver.h>
 #include <linux/regulator/machine.h>

 #include <soc/tegra/fuse.h>

 struct tegra_regulator_coupler {
 	struct regulator_coupler coupler;
 	struct regulator_dev *core_rdev;
 	struct regulator_dev *cpu_rdev;
 	int core_min_uV;
 };

 static inline struct tegra_regulator_coupler *
 to_tegra_coupler(struct regulator_coupler *coupler)
 {
 	return container_of(coupler, struct tegra_regulator_coupler, coupler);
 }

 static int tegra30_core_limit(struct tegra_regulator_coupler *tegra,
 			      struct regulator_dev *core_rdev)
 {
 	int core_min_uV = 0;
 	int core_max_uV;
 	int core_cur_uV;
 	int err;

 	if (tegra->core_min_uV > 0)
 		return tegra->core_min_uV;

 	core_cur_uV = regulator_get_voltage_rdev(core_rdev);
 	if (core_cur_uV < 0)
 		return core_cur_uV;

 	core_max_uV = max(core_cur_uV, 1200000);

 	err = regulator_check_voltage(core_rdev, &core_min_uV, &core_max_uV);
 	if (err)
 		return err;

 	/*
 	 * Limit minimum CORE voltage to a value left from bootloader or,
 	 * if it's unreasonably low value, to the most common 1.2v or to
 	 * whatever maximum value defined via board's device-tree.
 	 */
 	tegra->core_min_uV = core_max_uV;

 	pr_info("core minimum voltage limited to %duV\n", tegra->core_min_uV);

 	return tegra->core_min_uV;
 }

 static int tegra30_core_cpu_limit(int cpu_uV)
 {
 	if (cpu_uV < 800000)
 		return 950000;

 	if (cpu_uV < 900000)
 		return 1000000;

 	if (cpu_uV < 1000000)
 		return 1100000;

 	if (cpu_uV < 1100000)
 		return 1200000;

 	if (cpu_uV < 1250000) {
 		switch (tegra_sku_info.cpu_speedo_id) {
 		case 0 ... 1:
 		case 4:
 		case 7 ... 8:
 			return 1200000;

 		default:
 			return 1300000;
 		}
 	}

 	return -EINVAL;
 }

 static int tegra30_voltage_update(struct tegra_regulator_coupler *tegra,
 				  struct regulator_dev *cpu_rdev,
 				  struct regulator_dev *core_rdev)
 {
 	int core_min_uV, core_max_uV = INT_MAX;
 	int cpu_min_uV, cpu_max_uV = INT_MAX;
 	int cpu_min_uV_consumers = 0;
 	int core_min_limited_uV;
 	int core_target_uV;
 	int cpu_target_uV;
 	int core_max_step;
 	int cpu_max_step;
 	int max_spread;
 	int core_uV;
 	int cpu_uV;
 	int err;

 	/*
 	 * CPU voltage should not got lower than 300mV from the CORE.
 	 * CPU voltage should stay below the CORE by 100mV+, depending
 	 * by the CORE voltage. This applies to all Tegra30 SoC's.
 	 */
 	max_spread = cpu_rdev->constraints->max_spread[0];
 	cpu_max_step = cpu_rdev->constraints->max_uV_step;
 	core_max_step = core_rdev->constraints->max_uV_step;

 	if (!max_spread) {
 		pr_err_once("cpu-core max-spread is undefined in device-tree\n");
 		max_spread = 300000;
 	}

 	if (!cpu_max_step) {
 		pr_err_once("cpu max-step is undefined in device-tree\n");
 		cpu_max_step = 150000;
 	}

 	if (!core_max_step) {
 		pr_err_once("core max-step is undefined in device-tree\n");
 		core_max_step = 150000;
 	}

 	/*
 	 * The CORE voltage scaling is currently not hooked up in drivers,
 	 * hence we will limit the minimum CORE voltage to a reasonable value.
 	 * This should be good enough for the time being.
 	 */
 	core_min_uV = tegra30_core_limit(tegra, core_rdev);
 	if (core_min_uV < 0)
 		return core_min_uV;

 	err = regulator_check_consumers(core_rdev, &core_min_uV, &core_max_uV,
 					PM_SUSPEND_ON);
 	if (err)
 		return err;

 	core_uV = regulator_get_voltage_rdev(core_rdev);
 	if (core_uV < 0)
 		return core_uV;

 	cpu_min_uV = core_min_uV - max_spread;

 	err = regulator_check_consumers(cpu_rdev, &cpu_min_uV, &cpu_max_uV,
 					PM_SUSPEND_ON);
 	if (err)
 		return err;

 	err = regulator_check_consumers(cpu_rdev, &cpu_min_uV_consumers,
 					&cpu_max_uV, PM_SUSPEND_ON);
 	if (err)
 		return err;

 	err = regulator_check_voltage(cpu_rdev, &cpu_min_uV, &cpu_max_uV);
 	if (err)
 		return err;

 	cpu_uV = regulator_get_voltage_rdev(cpu_rdev);
 	if (cpu_uV < 0)
 		return cpu_uV;

 	/*
 	 * CPU's regulator may not have any consumers, hence the voltage
 	 * must not be changed in that case because CPU simply won't
 	 * survive the voltage drop if it's running on a higher frequency.
 	 */
 	if (!cpu_min_uV_consumers)
 		cpu_min_uV = cpu_uV;

 	/*
 	 * Bootloader shall set up voltages correctly, but if it
 	 * happens that there is a violation, then try to fix it
 	 * at first.
 	 */
 	core_min_limited_uV = tegra30_core_cpu_limit(cpu_uV);
 	if (core_min_limited_uV < 0)
 		return core_min_limited_uV;

 	core_min_uV = max(core_min_uV, tegra30_core_cpu_limit(cpu_min_uV));

 	err = regulator_check_voltage(core_rdev, &core_min_uV, &core_max_uV);
 	if (err)
 		return err;

 	if (core_min_limited_uV > core_uV) {
 		pr_err("core voltage constraint violated: %d %d %d\n",
 		       core_uV, core_min_limited_uV, cpu_uV);
 		goto update_core;
 	}

 	while (cpu_uV != cpu_min_uV || core_uV != core_min_uV) {
 		if (cpu_uV < cpu_min_uV) {
 			cpu_target_uV = min(cpu_uV + cpu_max_step, cpu_min_uV);
 		} else {
 			cpu_target_uV = max(cpu_uV - cpu_max_step, cpu_min_uV);
 			cpu_target_uV = max(core_uV - max_spread, cpu_target_uV);
 		}

 		err = regulator_set_voltage_rdev(cpu_rdev,
 						 cpu_target_uV,
 						 cpu_max_uV,
 						 PM_SUSPEND_ON);
 		if (err)
 			return err;

 		cpu_uV = cpu_target_uV;
 update_core:
 		core_min_limited_uV = tegra30_core_cpu_limit(cpu_uV);
 		if (core_min_limited_uV < 0)
 			return core_min_limited_uV;

 		core_target_uV = max(core_min_limited_uV, core_min_uV);

 		if (core_uV < core_target_uV) {
 			core_target_uV = min(core_target_uV, core_uV + core_max_step);
 			core_target_uV = min(core_target_uV, cpu_uV + max_spread);
 		} else {
 			core_target_uV = max(core_target_uV, core_uV - core_max_step);
 		}

 		err = regulator_set_voltage_rdev(core_rdev,
 						 core_target_uV,
 						 core_max_uV,
 						 PM_SUSPEND_ON);
 		if (err)
 			return err;

 		core_uV = core_target_uV;
 	}

 	return 0;
 }

 static int tegra30_regulator_balance_voltage(struct regulator_coupler *coupler,
 					     struct regulator_dev *rdev,
 					     suspend_state_t state)
 {
 	struct tegra_regulator_coupler *tegra = to_tegra_coupler(coupler);
 	struct regulator_dev *core_rdev = tegra->core_rdev;
 	struct regulator_dev *cpu_rdev = tegra->cpu_rdev;

 	if ((core_rdev != rdev && cpu_rdev != rdev) || state != PM_SUSPEND_ON) {
 		pr_err("regulators are not coupled properly\n");
 		return -EINVAL;
 	}

 	return tegra30_voltage_update(tegra, cpu_rdev, core_rdev);
 }

 static int tegra30_regulator_attach(struct regulator_coupler *coupler,
 				    struct regulator_dev *rdev)
 {
 	struct tegra_regulator_coupler *tegra = to_tegra_coupler(coupler);
 	struct device_node *np = rdev->dev.of_node;

 	if (of_property_read_bool(np, "nvidia,tegra-core-regulator") &&
 	    !tegra->core_rdev) {
 		tegra->core_rdev = rdev;
 		return 0;
 	}

 	if (of_property_read_bool(np, "nvidia,tegra-cpu-regulator") &&
 	    !tegra->cpu_rdev) {
 		tegra->cpu_rdev = rdev;
 		return 0;
 	}

 	return -EINVAL;
 }

 static int tegra30_regulator_detach(struct regulator_coupler *coupler,
 				    struct regulator_dev *rdev)
 {
 	struct tegra_regulator_coupler *tegra = to_tegra_coupler(coupler);

 	if (tegra->core_rdev == rdev) {
 		tegra->core_rdev = NULL;
 		return 0;
 	}

 	if (tegra->cpu_rdev == rdev) {
 		tegra->cpu_rdev = NULL;
 		return 0;
 	}

 	return -EINVAL;
 }

 static struct tegra_regulator_coupler tegra30_coupler = {
 	.coupler = {
 		.attach_regulator = tegra30_regulator_attach,
 		.detach_regulator = tegra30_regulator_detach,
 		.balance_voltage = tegra30_regulator_balance_voltage,
 	},
 };

 static int __init tegra_regulator_coupler_init(void)
 {
 	if (!of_machine_is_compatible("nvidia,tegra30"))
 		return 0;

 	return regulator_coupler_register(&tegra30_coupler.coupler);
 }
 arch_initcall(tegra_regulator_coupler_init);
	// SPDX-License-Identifier: GPL-2.0+
	/*
	* Voltage regulators coupler for NVIDIA Tegra30
	* Copyright (C) 2019 GRATE-DRIVER project
	*
	* Voltage constraints borrowed from downstream kernel sources
	* Copyright (C) 2010-2011 NVIDIA Corporation
	*/

	#define pr_fmt(fmt) "tegra voltage-coupler: " fmt

	#include <linux/init.h>
	#include <linux/kernel.h>
	#include <linux/of.h>
	#include <linux/regulator/coupler.h>
	#include <linux/regulator/driver.h>
	#include <linux/regulator/machine.h>

	#include <soc/tegra/fuse.h>

	struct tegra_regulator_coupler {
	struct regulator_coupler coupler;
	struct regulator_dev *core_rdev;
	struct regulator_dev *cpu_rdev;
	int core_min_uV;
	};

	static inline struct tegra_regulator_coupler *
	to_tegra_coupler(struct regulator_coupler *coupler)
	{
	return container_of(coupler, struct tegra_regulator_coupler, coupler);
	}

	static int tegra30_core_limit(struct tegra_regulator_coupler *tegra,
	struct regulator_dev *core_rdev)
	{
	int core_min_uV = 0;
	int core_max_uV;
	int core_cur_uV;
	int err;

	if (tegra->core_min_uV > 0)
	return tegra->core_min_uV;

	core_cur_uV = regulator_get_voltage_rdev(core_rdev);
	if (core_cur_uV < 0)
	return core_cur_uV;

	core_max_uV = max(core_cur_uV, 1200000);

	err = regulator_check_voltage(core_rdev, &core_min_uV, &core_max_uV);
	if (err)
	return err;

	/*
	* Limit minimum CORE voltage to a value left from bootloader or,
	* if it's unreasonably low value, to the most common 1.2v or to
	* whatever maximum value defined via board's device-tree.
	*/
	tegra->core_min_uV = core_max_uV;

	pr_info("core minimum voltage limited to %duV\n", tegra->core_min_uV);

	return tegra->core_min_uV;
	}

	static int tegra30_core_cpu_limit(int cpu_uV)
	{
	if (cpu_uV < 800000)
	return 950000;

	if (cpu_uV < 900000)
	return 1000000;

	if (cpu_uV < 1000000)
	return 1100000;

	if (cpu_uV < 1100000)
	return 1200000;

	if (cpu_uV < 1250000) {
	switch (tegra_sku_info.cpu_speedo_id) {
	case 0 ... 1:
	case 4:
	case 7 ... 8:
	return 1200000;

	default:
	return 1300000;
	}
	}

	return -EINVAL;
	}

	static int tegra30_voltage_update(struct tegra_regulator_coupler *tegra,
	struct regulator_dev *cpu_rdev,
	struct regulator_dev *core_rdev)
	{
	int core_min_uV, core_max_uV = INT_MAX;
	int cpu_min_uV, cpu_max_uV = INT_MAX;
	int cpu_min_uV_consumers = 0;
	int core_min_limited_uV;
	int core_target_uV;
	int cpu_target_uV;
	int core_max_step;
	int cpu_max_step;
	int max_spread;
	int core_uV;
	int cpu_uV;
	int err;

	/*
	* CPU voltage should not got lower than 300mV from the CORE.
	* CPU voltage should stay below the CORE by 100mV+, depending
	* by the CORE voltage. This applies to all Tegra30 SoC's.
	*/
	max_spread = cpu_rdev->constraints->max_spread[0];
	cpu_max_step = cpu_rdev->constraints->max_uV_step;
	core_max_step = core_rdev->constraints->max_uV_step;

	if (!max_spread) {
	pr_err_once("cpu-core max-spread is undefined in device-tree\n");
	max_spread = 300000;
	}

	if (!cpu_max_step) {
	pr_err_once("cpu max-step is undefined in device-tree\n");
	cpu_max_step = 150000;
	}

	if (!core_max_step) {
	pr_err_once("core max-step is undefined in device-tree\n");
	core_max_step = 150000;
	}

	/*
	* The CORE voltage scaling is currently not hooked up in drivers,
	* hence we will limit the minimum CORE voltage to a reasonable value.
	* This should be good enough for the time being.
	*/
	core_min_uV = tegra30_core_limit(tegra, core_rdev);
	if (core_min_uV < 0)
	return core_min_uV;

	err = regulator_check_consumers(core_rdev, &core_min_uV, &core_max_uV,
	PM_SUSPEND_ON);
	if (err)
	return err;

	core_uV = regulator_get_voltage_rdev(core_rdev);
	if (core_uV < 0)
	return core_uV;

	cpu_min_uV = core_min_uV - max_spread;

	err = regulator_check_consumers(cpu_rdev, &cpu_min_uV, &cpu_max_uV,
	PM_SUSPEND_ON);
	if (err)
	return err;

	err = regulator_check_consumers(cpu_rdev, &cpu_min_uV_consumers,
	&cpu_max_uV, PM_SUSPEND_ON);
	if (err)
	return err;

	err = regulator_check_voltage(cpu_rdev, &cpu_min_uV, &cpu_max_uV);
	if (err)
	return err;

	cpu_uV = regulator_get_voltage_rdev(cpu_rdev);
	if (cpu_uV < 0)
	return cpu_uV;

	/*
	* CPU's regulator may not have any consumers, hence the voltage
	* must not be changed in that case because CPU simply won't
	* survive the voltage drop if it's running on a higher frequency.
	*/
	if (!cpu_min_uV_consumers)
	cpu_min_uV = cpu_uV;

	/*
	* Bootloader shall set up voltages correctly, but if it
	* happens that there is a violation, then try to fix it
	* at first.
	*/
	core_min_limited_uV = tegra30_core_cpu_limit(cpu_uV);
	if (core_min_limited_uV < 0)
	return core_min_limited_uV;

	core_min_uV = max(core_min_uV, tegra30_core_cpu_limit(cpu_min_uV));

	err = regulator_check_voltage(core_rdev, &core_min_uV, &core_max_uV);
	if (err)
	return err;

	if (core_min_limited_uV > core_uV) {
	pr_err("core voltage constraint violated: %d %d %d\n",
	core_uV, core_min_limited_uV, cpu_uV);
	goto update_core;
	}

	while (cpu_uV != cpu_min_uV \|\| core_uV != core_min_uV) {
	if (cpu_uV < cpu_min_uV) {
	cpu_target_uV = min(cpu_uV + cpu_max_step, cpu_min_uV);
	} else {
	cpu_target_uV = max(cpu_uV - cpu_max_step, cpu_min_uV);
	cpu_target_uV = max(core_uV - max_spread, cpu_target_uV);
	}

	err = regulator_set_voltage_rdev(cpu_rdev,
	cpu_target_uV,
	cpu_max_uV,
	PM_SUSPEND_ON);
	if (err)
	return err;

	cpu_uV = cpu_target_uV;
	update_core:
	core_min_limited_uV = tegra30_core_cpu_limit(cpu_uV);
	if (core_min_limited_uV < 0)
	return core_min_limited_uV;

	core_target_uV = max(core_min_limited_uV, core_min_uV);

	if (core_uV < core_target_uV) {
	core_target_uV = min(core_target_uV, core_uV + core_max_step);
	core_target_uV = min(core_target_uV, cpu_uV + max_spread);
	} else {
	core_target_uV = max(core_target_uV, core_uV - core_max_step);
	}

	err = regulator_set_voltage_rdev(core_rdev,
	core_target_uV,
	core_max_uV,
	PM_SUSPEND_ON);
	if (err)
	return err;

	core_uV = core_target_uV;
	}

	return 0;
	}

	static int tegra30_regulator_balance_voltage(struct regulator_coupler *coupler,
	struct regulator_dev *rdev,
	suspend_state_t state)
	{
	struct tegra_regulator_coupler *tegra = to_tegra_coupler(coupler);
	struct regulator_dev *core_rdev = tegra->core_rdev;
	struct regulator_dev *cpu_rdev = tegra->cpu_rdev;

	if ((core_rdev != rdev && cpu_rdev != rdev) \|\| state != PM_SUSPEND_ON) {
	pr_err("regulators are not coupled properly\n");
	return -EINVAL;
	}

	return tegra30_voltage_update(tegra, cpu_rdev, core_rdev);
	}

	static int tegra30_regulator_attach(struct regulator_coupler *coupler,
	struct regulator_dev *rdev)
	{
	struct tegra_regulator_coupler *tegra = to_tegra_coupler(coupler);
	struct device_node *np = rdev->dev.of_node;

	if (of_property_read_bool(np, "nvidia,tegra-core-regulator") &&
	!tegra->core_rdev) {
	tegra->core_rdev = rdev;
	return 0;
	}

	if (of_property_read_bool(np, "nvidia,tegra-cpu-regulator") &&
	!tegra->cpu_rdev) {
	tegra->cpu_rdev = rdev;
	return 0;
	}

	return -EINVAL;
	}

	static int tegra30_regulator_detach(struct regulator_coupler *coupler,
	struct regulator_dev *rdev)
	{
	struct tegra_regulator_coupler *tegra = to_tegra_coupler(coupler);

	if (tegra->core_rdev == rdev) {
	tegra->core_rdev = NULL;
	return 0;
	}

	if (tegra->cpu_rdev == rdev) {
	tegra->cpu_rdev = NULL;
	return 0;
	}

	return -EINVAL;
	}

	static struct tegra_regulator_coupler tegra30_coupler = {
	.coupler = {
	.attach_regulator = tegra30_regulator_attach,
	.detach_regulator = tegra30_regulator_detach,
	.balance_voltage = tegra30_regulator_balance_voltage,
	},
	};

	static int __init tegra_regulator_coupler_init(void)
	{
	if (!of_machine_is_compatible("nvidia,tegra30"))
	return 0;

	return regulator_coupler_register(&tegra30_coupler.coupler);
	}
	arch_initcall(tegra_regulator_coupler_init);