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Commit 375365b9 authored by Ram Chandrasekar's avatar Ram Chandrasekar
Browse files

drivers: thermal: regulator_cdev: Add a voltage regulator cooling device 



Certain regulators are required to be restricted to a voltage floor on
thermal condition. In order to support this, add a new regulator cooling
device.

This cooling device can place a voltage floor on rpmph ARC type regulator.
Request to place a voltage cap will be ignored by this cooling device.

Change-Id: I0f7128ebadfa83eb7ce8014aa5f1602b04f36672
Signed-off-by: default avatarRam Chandrasekar <rkumbako@codeaurora.org>
parent aa884c2e

Documentation/devicetree/bindings/thermal/regulator-cdev.txt

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+38 −0
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Regulator cooling device.



The regulator cooling device, will be used to place a voltage floor

restriction on a rail.



Properties:



- compatible:

	Usage: required

	Value type: <string>

	Definition: shall be "qcom,regulator-cooling-device"



- cdev-supply:

	Usage: required

	Value type: <phandle>

	Definition: phandle to the regulator to which the cooling device will

			place a floor mitigation.



- regulator-levels:

	Usage: required

	Value type: <U32 array>

	Definition: Array of regulator voltages the cooling device should

			use to place a floor restriction. The voltages should

			be specified in descending order.



- #cooling-cells: Must be 2. Please refer to

			<devicetree/bindings/thermal/thermal.txt> for more

			details.



Example:



	mv_cdev: mx-cdev-lvl {

		compatible = "qcom,regulator-cooling-device";

		cdev-supply = <&regulator-cdev-supply>;

		regulator-levels = <RPMH_REGULATOR_LEVEL_NOM

			RPMH_REGULATOR_LEVEL_OFF>;

		#cooling-cells = <2>;

	};

drivers/thermal/qcom/Kconfig

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@@ -60,3 +60,14 @@ config QTI_QMI_COOLING_DEVICE 
	   remote subsystem voltage restriction at low temperatures etc.

	   The QMI cooling device will interface with remote subsystem

	   using QTI QMI interface.



config REGULATOR_COOLING_DEVICE

	bool "Regulator voltage floor cooling device"

	depends on REGULATOR && THERMAL_OF

	help

	  This implements a mitigation device to place a minimum voltage floor

	  on a particular regulator. This mitigation device will be used by low

	  temperature reliability rules to mitigate a regulator at nominal

	  voltage.



	  If you want this support, you should say Y here.

drivers/thermal/qcom/Makefile

+1 −0
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@@ -4,4 +4,5 @@ obj-$(CONFIG_MSM_BCL_PERIPHERAL_CTL) += bcl_peripheral.o 
obj-$(CONFIG_QTI_THERMAL_LIMITS_DCVS) += msm_lmh_dcvs.o lmh_dbg.o

obj-$(CONFIG_QTI_VIRTUAL_SENSOR) += qti_virtual_sensor.o

obj-$(CONFIG_QTI_AOP_REG_COOLING_DEVICE) += regulator_aop_cdev.o

obj-$(CONFIG_REGULATOR_COOLING_DEVICE) += regulator_cdev.o

obj-$(CONFIG_QTI_QMI_COOLING_DEVICE) += thermal_mitigation_device_service_v01.o qmi_cooling.o

drivers/thermal/qcom/regulator_cdev.c

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/* Copyright (c) 2017, The Linux Foundation. All rights reserved.

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License version 2 and

 * only version 2 as published by the Free Software Foundation.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 */



#include <linux/module.h>

#include <linux/platform_device.h>

#include <linux/thermal.h>

#include <linux/err.h>

#include <linux/slab.h>

#include <linux/regulator/consumer.h>



#define REG_CDEV_DRIVER "reg-cooling-device"



struct reg_cooling_device {

	struct regulator		*reg;

	struct thermal_cooling_device	*cool_dev;

	unsigned int			min_reg_state;

	unsigned int			*lvl;

	unsigned int			lvl_ct;

	char				reg_name[THERMAL_NAME_LENGTH];

	bool				reg_enable;

};



static int reg_get_max_state(struct thermal_cooling_device *cdev,

				 unsigned long *state)

{

	struct reg_cooling_device *reg_dev = cdev->devdata;



	*state = reg_dev->lvl_ct;

	return 0;

}



static int reg_get_min_state(struct thermal_cooling_device *cdev,

				 unsigned long *state)

{

	struct reg_cooling_device *reg_dev = cdev->devdata;



	*state = reg_dev->min_reg_state;

	return 0;

}



static int reg_set_min_state(struct thermal_cooling_device *cdev,

				 unsigned long state)

{

	struct reg_cooling_device *reg_dev = cdev->devdata;

	int ret = 0;



	if (state > reg_dev->lvl_ct)

		state = reg_dev->lvl_ct;



	if (reg_dev->min_reg_state == state)

		return ret;



	ret = regulator_set_voltage(reg_dev->reg,

			reg_dev->lvl[state], INT_MAX);

	if (ret) {

		dev_err(&cdev->device,

			"switching to floor %lu err:%d\n",

			state, ret);

		return ret;

	}

	if (reg_dev->reg_enable && state == reg_dev->lvl_ct) {

		ret = regulator_disable(reg_dev->reg);

		if (ret) {

			dev_err(&cdev->device,

				"regulator disable err:%d\n", ret);

			return ret;

		}

		reg_dev->reg_enable = false;

	} else if (!reg_dev->reg_enable && state != reg_dev->lvl_ct) {

		ret = regulator_enable(reg_dev->reg);

		if (ret) {

			dev_err(&cdev->device,

				"regulator enable err:%d\n", ret);

			return ret;

		}

		reg_dev->reg_enable = true;

	}

	reg_dev->min_reg_state = state;



	return ret;

}



static int reg_get_cur_state(struct thermal_cooling_device *cdev,

				 unsigned long *state)

{

	*state = 0;

	return 0;

}



static int reg_set_cur_state(struct thermal_cooling_device *cdev,

				 unsigned long state)

{

	/* regulator cooling device doesn't support voltage ceil */

	return 0;

}



static struct thermal_cooling_device_ops reg_device_ops = {

	.get_max_state = reg_get_max_state,

	.get_cur_state = reg_get_cur_state,

	.set_cur_state = reg_set_cur_state,

	.set_min_state = reg_set_min_state,

	.get_min_state = reg_get_min_state,

};



static int reg_cdev_probe(struct platform_device *pdev)

{

	struct reg_cooling_device *reg_dev;

	int ret = 0;

	struct device_node *np;



	np = dev_of_node(&pdev->dev);

	if (!np) {

		dev_err(&pdev->dev,

			"of node not available for cooling device\n");

		return -EINVAL;

	}



	reg_dev = devm_kzalloc(&pdev->dev, sizeof(*reg_dev), GFP_KERNEL);

	if (!reg_dev)

		return -ENOMEM;



	reg_dev->reg = devm_regulator_get(&pdev->dev, "regulator-cdev");

	if (IS_ERR_OR_NULL(reg_dev->reg)) {

		ret = PTR_ERR(reg_dev->reg);

		dev_err(&pdev->dev, "regulator register err:%d\n", ret);

		return ret;

	}

	ret = of_property_count_u32_elems(np, "regulator-levels");

	if (ret <= 0) {

		dev_err(&pdev->dev, "Invalid levels err:%d\n", ret);

		return ret;

	}

	reg_dev->lvl_ct = ret;

	reg_dev->lvl = devm_kcalloc(&pdev->dev, reg_dev->lvl_ct,

			sizeof(*reg_dev->lvl), GFP_KERNEL);

	if (!reg_dev->lvl)

		return -ENOMEM;

	ret = of_property_read_u32_array(np, "regulator-levels",

				reg_dev->lvl, reg_dev->lvl_ct);

	if (ret) {

		dev_err(&pdev->dev, "cdev level fetch err:%d\n", ret);

		return ret;

	}

	/* level count is an index and it depicts the max possible index */

	reg_dev->lvl_ct--;

	reg_dev->min_reg_state = reg_dev->lvl_ct;

	reg_dev->reg_enable = false;

	strlcpy(reg_dev->reg_name, np->name, THERMAL_NAME_LENGTH);



	reg_dev->cool_dev = thermal_of_cooling_device_register(

					np, reg_dev->reg_name, reg_dev,

					&reg_device_ops);

	if (IS_ERR(reg_dev->cool_dev)) {

		ret = PTR_ERR(reg_dev->cool_dev);

		dev_err(&pdev->dev, "regulator cdev register err:%d\n",

				ret);

		return ret;

	}



	return ret;

}



static const struct of_device_id reg_cdev_of_match[] = {

	{.compatible = "qcom,regulator-cooling-device", },

	{}

};



static struct platform_driver reg_cdev_driver = {

	.driver = {

		.name = REG_CDEV_DRIVER,

		.of_match_table = reg_cdev_of_match,

	},

	.probe = reg_cdev_probe,

};

builtin_platform_driver(reg_cdev_driver);