drivers: regulator_aop: Add snapshot for AOP regulator cdev

RPMh regulator cooling device.

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

restriction on a rail. This cooling device will use a QMP AOP mail box to send

the message to apply and clear voltage floor restriction.

The cooling device node should be a child of the regulator devicetree node,

which it is trying to place the floor restriction.

Properties:

- compatible:

	Usage: required

	Value type: <string>

	Definition: shall be "qcom,rpmh-reg-cdev"

- qcom,reg-resource-name:

	Usage: required

	Value type: <string>

	Definition: The regulator resource name to be used for communicating

			with RPMh. This value should be any of the below

			resource name,

			cx -> For CX rail,

			mx -> For MX rail,

			ebi -> For EBI rail.

- mboxes:

	Usage: required

	Value type: <phandle>

	Definition: A phandle to the QMP AOP mail box, that needs to be used

			for sending the floor restriction message.

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

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

			details.

Example:

	vdd_cx: rpmh-cx-regulator-cdev {

		compatible = "qcom,rpmh-reg-cdev";

		mboxes = <&qmp_aop 0>;

		qcom,reg-resource-name = "cx";

		#cooling-cells = <2>;

	};

	  each cluster can be used to perform quick thermal mitigations by

	  tracking temperatures of the CPUs and taking thermal action in the

	  hardware without s/w intervention.

config QTI_AOP_REG_COOLING_DEVICE

	bool "QTI AOP Regulator cooling device"

	depends on THERMAL_OF && MSM_QMP

	help

	  This enables the AOP based Regulator cooling device. This cooling

	  device will be used by QTI chipset to place a floor voltage

	  restriction at low temperatures. The cooling device will message

	  the AOP using mail box to establish the floor voltage.

obj-$(CONFIG_QCOM_TSENS)	+= qcom_tsens.o

qcom_tsens-y			+= tsens.o tsens-common.o tsens-8916.o tsens-8974.o tsens-8960.o tsens-8996.o

obj-$(CONFIG_QTI_THERMAL_LIMITS_DCVS) += msm_lmh_dcvs.o lmh_dbg.o

obj-$(CONFIG_QTI_AOP_REG_COOLING_DEVICE) += regulator_aop_cdev.o

/* Copyright (c) 2017-2018, 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/mailbox_client.h>

#define REG_CDEV_DRIVER "reg-aop-cooling-device"

#define REG_MSG_FORMAT "{class:volt_flr, event:zero_temp, res:%s, value:%s}"

#define REG_CDEV_MAX_STATE 1

#define MBOX_TOUT_MS 1000

#define REG_MSG_MAX_LEN 100

struct reg_cooling_device {

	struct thermal_cooling_device	*cdev;

	unsigned int			min_state;

	const char			*resource_name;

	struct mbox_chan		*qmp_chan;

	struct mbox_client		*client;

};

struct aop_msg {

	uint32_t len;

	void *msg;

};

enum regulator_rail_type {

	REG_COOLING_CX,

	REG_COOLING_MX,

	REG_COOLING_EBI,

	REG_COOLING_NR,

};

static char *regulator_rail[REG_COOLING_NR] = {

	"cx",

	"mx",

	"ebi",

};

static int aop_send_msg(struct reg_cooling_device *reg_dev, int min_state)

{

	char msg_buf[REG_MSG_MAX_LEN] = {0};

	int ret = 0;

	struct aop_msg msg;

	if (!reg_dev->qmp_chan) {

		pr_err("mbox not initialized for resource:%s\n",

				reg_dev->resource_name);

		return -EINVAL;

	}

	ret = snprintf(msg_buf, REG_MSG_MAX_LEN, REG_MSG_FORMAT,

			reg_dev->resource_name,

			(min_state == REG_CDEV_MAX_STATE) ? "off" : "on");

	if (ret >= REG_MSG_MAX_LEN) {

		pr_err("Message too long for resource:%s\n",

				reg_dev->resource_name);

		return -E2BIG;

	}

	msg.len = REG_MSG_MAX_LEN;

	msg.msg = msg_buf;

	ret = mbox_send_message(reg_dev->qmp_chan, &msg);

	return (ret < 0) ? ret : 0;

}

static int reg_get_max_state(struct thermal_cooling_device *cdev,

				unsigned long *state)

{

	*state = REG_CDEV_MAX_STATE;

	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_state;

	return 0;

}

static int reg_send_min_state(struct thermal_cooling_device *cdev,

				unsigned long state)

{

	struct reg_cooling_device *reg_dev = cdev->devdata;

	int ret = 0;

	if (state > REG_CDEV_MAX_STATE)

		state = REG_CDEV_MAX_STATE;

	if (reg_dev->min_state == state)

		return ret;

	ret = aop_send_msg(reg_dev, state);

	if (ret) {

		pr_err("regulator:%s switching to floor %lu error. err:%d\n",

			reg_dev->resource_name, state, ret);

	} else {

		pr_debug("regulator:%s switched to %lu from %d\n",

			reg_dev->resource_name, state, reg_dev->min_state);

		reg_dev->min_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_send_cur_state(struct thermal_cooling_device *cdev,

				unsigned long state)

{

	return 0;

}

static struct thermal_cooling_device_ops reg_dev_ops = {

	.get_max_state = reg_get_max_state,

	.get_cur_state = reg_get_cur_state,

	.set_cur_state = reg_send_cur_state,

	.set_min_state = reg_send_min_state,

	.get_min_state = reg_get_min_state,

};

static int reg_init_mbox(struct platform_device *pdev,

			struct reg_cooling_device *reg_dev)

{

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

					GFP_KERNEL);

	if (!reg_dev->client)

		return -ENOMEM;

	reg_dev->client->dev = &pdev->dev;

	reg_dev->client->tx_block = true;

	reg_dev->client->tx_tout = MBOX_TOUT_MS;

	reg_dev->client->knows_txdone = false;

	reg_dev->qmp_chan = mbox_request_channel(reg_dev->client, 0);

	if (IS_ERR(reg_dev->qmp_chan)) {

		dev_err(&pdev->dev, "Mbox request failed. err:%ld\n",

				PTR_ERR(reg_dev->qmp_chan));

		return PTR_ERR(reg_dev->qmp_chan);

	}

	return 0;

}

static int reg_dev_probe(struct platform_device *pdev)

{

	int ret = 0, idx = 0;

	struct reg_cooling_device *reg_dev = NULL;

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

	if (!reg_dev)

		return -ENOMEM;

	ret = reg_init_mbox(pdev, reg_dev);

	if (ret)

		return ret;

	ret = of_property_read_string(pdev->dev.of_node,

			"qcom,reg-resource-name",

			&reg_dev->resource_name);

	if (ret) {

		dev_err(&pdev->dev, "Error reading resource name. err:%d\n",

			ret);

		goto mbox_free;

	}

	for (idx = 0; idx < REG_COOLING_NR; idx++) {

		if (!strcmp(reg_dev->resource_name, regulator_rail[idx]))

			break;

	}

	if (idx == REG_COOLING_NR) {

		dev_err(&pdev->dev, "Invalid regulator resource name:%s\n",

				reg_dev->resource_name);

		ret = -EINVAL;

		goto mbox_free;

	}

	reg_dev->min_state = REG_CDEV_MAX_STATE;

	reg_dev->cdev = thermal_of_cooling_device_register(

				pdev->dev.of_node,

				(char *)reg_dev->resource_name,

				reg_dev, &reg_dev_ops);

	if (IS_ERR(reg_dev->cdev))

		goto mbox_free;

	return ret;

mbox_free:

	mbox_free_channel(reg_dev->qmp_chan);

	return ret;

}

static const struct of_device_id reg_dev_of_match[] = {

	{.compatible = "qcom,rpmh-reg-cdev", },

	{}

};

static struct platform_driver reg_dev_driver = {

	.driver = {

		.name = REG_CDEV_DRIVER,

		.of_match_table = reg_dev_of_match,

	},

	.probe = reg_dev_probe,

};

builtin_platform_driver(reg_dev_driver);