drivers/spmi/spmi.c - kernel/common - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * Copyright (c) 2012-2015, The Linux Foundation. All rights reserved.
  */
 #include <linux/kernel.h>
 #include <linux/errno.h>
 #include <linux/idr.h>
 #include <linux/slab.h>
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/of_device.h>
 #include <linux/platform_device.h>
 #include <linux/spmi.h>
 #include <linux/pm_runtime.h>

 #include <dt-bindings/spmi/spmi.h>
 #define CREATE_TRACE_POINTS
 #include <trace/events/spmi.h>

 static bool is_registered;
 static DEFINE_IDA(ctrl_ida);

 static void spmi_dev_release(struct device *dev)
 {
 	struct spmi_device *sdev = to_spmi_device(dev);
 	kfree(sdev);
 }

 static const struct device_type spmi_dev_type = {
 	.release	= spmi_dev_release,
 };

 static void spmi_ctrl_release(struct device *dev)
 {
 	struct spmi_controller *ctrl = to_spmi_controller(dev);
 	ida_simple_remove(&ctrl_ida, ctrl->nr);
 	kfree(ctrl);
 }

 static const struct device_type spmi_ctrl_type = {
 	.release	= spmi_ctrl_release,
 };

 static int spmi_device_match(struct device *dev, struct device_driver *drv)
 {
 	if (of_driver_match_device(dev, drv))
 		return 1;

 	if (drv->name)
 		return strncmp(dev_name(dev), drv->name,
 			       SPMI_NAME_SIZE) == 0;

 	return 0;
 }

 /**
  * spmi_device_add() - add a device previously constructed via spmi_device_alloc()
  * @sdev:	spmi_device to be added
  */
 int spmi_device_add(struct spmi_device *sdev)
 {
 	struct spmi_controller *ctrl = sdev->ctrl;
 	int err;

 	dev_set_name(&sdev->dev, "%d-%02x", ctrl->nr, sdev->usid);

 	err = device_add(&sdev->dev);
 	if (err < 0) {
 		dev_err(&sdev->dev, "Can't add %s, status %d\n",
 			dev_name(&sdev->dev), err);
 		goto err_device_add;
 	}

 	dev_dbg(&sdev->dev, "device %s registered\n", dev_name(&sdev->dev));

 err_device_add:
 	return err;
 }
 EXPORT_SYMBOL_GPL(spmi_device_add);

 /**
  * spmi_device_remove(): remove an SPMI device
  * @sdev:	spmi_device to be removed
  */
 void spmi_device_remove(struct spmi_device *sdev)
 {
 	device_unregister(&sdev->dev);
 }
 EXPORT_SYMBOL_GPL(spmi_device_remove);

 static inline int
 spmi_cmd(struct spmi_controller *ctrl, u8 opcode, u8 sid)
 {
 	int ret;

 	if (!ctrl || !ctrl->cmd || ctrl->dev.type != &spmi_ctrl_type)
 		return -EINVAL;

 	ret = ctrl->cmd(ctrl, opcode, sid);
 	trace_spmi_cmd(opcode, sid, ret);
 	return ret;
 }

 static inline int spmi_read_cmd(struct spmi_controller *ctrl, u8 opcode,
 				u8 sid, u16 addr, u8 *buf, size_t len)
 {
 	int ret;

 	if (!ctrl || !ctrl->read_cmd || ctrl->dev.type != &spmi_ctrl_type)
 		return -EINVAL;

 	trace_spmi_read_begin(opcode, sid, addr);
 	ret = ctrl->read_cmd(ctrl, opcode, sid, addr, buf, len);
 	trace_spmi_read_end(opcode, sid, addr, ret, len, buf);
 	return ret;
 }

 static inline int spmi_write_cmd(struct spmi_controller *ctrl, u8 opcode,
 				 u8 sid, u16 addr, const u8 *buf, size_t len)
 {
 	int ret;

 	if (!ctrl || !ctrl->write_cmd || ctrl->dev.type != &spmi_ctrl_type)
 		return -EINVAL;

 	trace_spmi_write_begin(opcode, sid, addr, len, buf);
 	ret = ctrl->write_cmd(ctrl, opcode, sid, addr, buf, len);
 	trace_spmi_write_end(opcode, sid, addr, ret);
 	return ret;
 }

 /**
  * spmi_register_read() - register read
  * @sdev:	SPMI device.
  * @addr:	slave register address (5-bit address).
  * @buf:	buffer to be populated with data from the Slave.
  *
  * Reads 1 byte of data from a Slave device register.
  */
 int spmi_register_read(struct spmi_device *sdev, u8 addr, u8 *buf)
 {
 	/* 5-bit register address */
 	if (addr > 0x1F)
 		return -EINVAL;

 	return spmi_read_cmd(sdev->ctrl, SPMI_CMD_READ, sdev->usid, addr,
 			     buf, 1);
 }
 EXPORT_SYMBOL_GPL(spmi_register_read);

 /**
  * spmi_ext_register_read() - extended register read
  * @sdev:	SPMI device.
  * @addr:	slave register address (8-bit address).
  * @buf:	buffer to be populated with data from the Slave.
  * @len:	the request number of bytes to read (up to 16 bytes).
  *
  * Reads up to 16 bytes of data from the extended register space on a
  * Slave device.
  */
 int spmi_ext_register_read(struct spmi_device *sdev, u8 addr, u8 *buf,
 			   size_t len)
 {
 	/* 8-bit register address, up to 16 bytes */
 	if (len == 0 || len > 16)
 		return -EINVAL;

 	return spmi_read_cmd(sdev->ctrl, SPMI_CMD_EXT_READ, sdev->usid, addr,
 			     buf, len);
 }
 EXPORT_SYMBOL_GPL(spmi_ext_register_read);

 /**
  * spmi_ext_register_readl() - extended register read long
  * @sdev:	SPMI device.
  * @addr:	slave register address (16-bit address).
  * @buf:	buffer to be populated with data from the Slave.
  * @len:	the request number of bytes to read (up to 8 bytes).
  *
  * Reads up to 8 bytes of data from the extended register space on a
  * Slave device using 16-bit address.
  */
 int spmi_ext_register_readl(struct spmi_device *sdev, u16 addr, u8 *buf,
 			    size_t len)
 {
 	/* 16-bit register address, up to 8 bytes */
 	if (len == 0 || len > 8)
 		return -EINVAL;

 	return spmi_read_cmd(sdev->ctrl, SPMI_CMD_EXT_READL, sdev->usid, addr,
 			     buf, len);
 }
 EXPORT_SYMBOL_GPL(spmi_ext_register_readl);

 /**
  * spmi_register_write() - register write
  * @sdev:	SPMI device
  * @addr:	slave register address (5-bit address).
  * @data:	buffer containing the data to be transferred to the Slave.
  *
  * Writes 1 byte of data to a Slave device register.
  */
 int spmi_register_write(struct spmi_device *sdev, u8 addr, u8 data)
 {
 	/* 5-bit register address */
 	if (addr > 0x1F)
 		return -EINVAL;

 	return spmi_write_cmd(sdev->ctrl, SPMI_CMD_WRITE, sdev->usid, addr,
 			      &data, 1);
 }
 EXPORT_SYMBOL_GPL(spmi_register_write);

 /**
  * spmi_register_zero_write() - register zero write
  * @sdev:	SPMI device.
  * @data:	the data to be written to register 0 (7-bits).
  *
  * Writes data to register 0 of the Slave device.
  */
 int spmi_register_zero_write(struct spmi_device *sdev, u8 data)
 {
 	return spmi_write_cmd(sdev->ctrl, SPMI_CMD_ZERO_WRITE, sdev->usid, 0,
 			      &data, 1);
 }
 EXPORT_SYMBOL_GPL(spmi_register_zero_write);

 /**
  * spmi_ext_register_write() - extended register write
  * @sdev:	SPMI device.
  * @addr:	slave register address (8-bit address).
  * @buf:	buffer containing the data to be transferred to the Slave.
  * @len:	the request number of bytes to read (up to 16 bytes).
  *
  * Writes up to 16 bytes of data to the extended register space of a
  * Slave device.
  */
 int spmi_ext_register_write(struct spmi_device *sdev, u8 addr, const u8 *buf,
 			    size_t len)
 {
 	/* 8-bit register address, up to 16 bytes */
 	if (len == 0 || len > 16)
 		return -EINVAL;

 	return spmi_write_cmd(sdev->ctrl, SPMI_CMD_EXT_WRITE, sdev->usid, addr,
 			      buf, len);
 }
 EXPORT_SYMBOL_GPL(spmi_ext_register_write);

 /**
  * spmi_ext_register_writel() - extended register write long
  * @sdev:	SPMI device.
  * @addr:	slave register address (16-bit address).
  * @buf:	buffer containing the data to be transferred to the Slave.
  * @len:	the request number of bytes to read (up to 8 bytes).
  *
  * Writes up to 8 bytes of data to the extended register space of a
  * Slave device using 16-bit address.
  */
 int spmi_ext_register_writel(struct spmi_device *sdev, u16 addr, const u8 *buf,
 			     size_t len)
 {
 	/* 4-bit Slave Identifier, 16-bit register address, up to 8 bytes */
 	if (len == 0 || len > 8)
 		return -EINVAL;

 	return spmi_write_cmd(sdev->ctrl, SPMI_CMD_EXT_WRITEL, sdev->usid,
 			      addr, buf, len);
 }
 EXPORT_SYMBOL_GPL(spmi_ext_register_writel);

 /**
  * spmi_command_reset() - sends RESET command to the specified slave
  * @sdev:	SPMI device.
  *
  * The Reset command initializes the Slave and forces all registers to
  * their reset values. The Slave shall enter the STARTUP state after
  * receiving a Reset command.
  */
 int spmi_command_reset(struct spmi_device *sdev)
 {
 	return spmi_cmd(sdev->ctrl, SPMI_CMD_RESET, sdev->usid);
 }
 EXPORT_SYMBOL_GPL(spmi_command_reset);

 /**
  * spmi_command_sleep() - sends SLEEP command to the specified SPMI device
  * @sdev:	SPMI device.
  *
  * The Sleep command causes the Slave to enter the user defined SLEEP state.
  */
 int spmi_command_sleep(struct spmi_device *sdev)
 {
 	return spmi_cmd(sdev->ctrl, SPMI_CMD_SLEEP, sdev->usid);
 }
 EXPORT_SYMBOL_GPL(spmi_command_sleep);

 /**
  * spmi_command_wakeup() - sends WAKEUP command to the specified SPMI device
  * @sdev:	SPMI device.
  *
  * The Wakeup command causes the Slave to move from the SLEEP state to
  * the ACTIVE state.
  */
 int spmi_command_wakeup(struct spmi_device *sdev)
 {
 	return spmi_cmd(sdev->ctrl, SPMI_CMD_WAKEUP, sdev->usid);
 }
 EXPORT_SYMBOL_GPL(spmi_command_wakeup);

 /**
  * spmi_command_shutdown() - sends SHUTDOWN command to the specified SPMI device
  * @sdev:	SPMI device.
  *
  * The Shutdown command causes the Slave to enter the SHUTDOWN state.
  */
 int spmi_command_shutdown(struct spmi_device *sdev)
 {
 	return spmi_cmd(sdev->ctrl, SPMI_CMD_SHUTDOWN, sdev->usid);
 }
 EXPORT_SYMBOL_GPL(spmi_command_shutdown);

 static int spmi_drv_probe(struct device *dev)
 {
 	const struct spmi_driver *sdrv = to_spmi_driver(dev->driver);
 	struct spmi_device *sdev = to_spmi_device(dev);
 	int err;

 	pm_runtime_get_noresume(dev);
 	pm_runtime_set_active(dev);
 	pm_runtime_enable(dev);

 	err = sdrv->probe(sdev);
 	if (err)
 		goto fail_probe;

 	return 0;

 fail_probe:
 	pm_runtime_disable(dev);
 	pm_runtime_set_suspended(dev);
 	pm_runtime_put_noidle(dev);
 	return err;
 }

 static int spmi_drv_remove(struct device *dev)
 {
 	const struct spmi_driver *sdrv = to_spmi_driver(dev->driver);

 	pm_runtime_get_sync(dev);
 	sdrv->remove(to_spmi_device(dev));
 	pm_runtime_put_noidle(dev);

 	pm_runtime_disable(dev);
 	pm_runtime_set_suspended(dev);
 	pm_runtime_put_noidle(dev);
 	return 0;
 }

 static int spmi_drv_uevent(struct device *dev, struct kobj_uevent_env *env)
 {
 	int ret;

 	ret = of_device_uevent_modalias(dev, env);
 	if (ret != -ENODEV)
 		return ret;

 	return 0;
 }

 static struct bus_type spmi_bus_type = {
 	.name		= "spmi",
 	.match		= spmi_device_match,
 	.probe		= spmi_drv_probe,
 	.remove		= spmi_drv_remove,
 	.uevent		= spmi_drv_uevent,
 };

 /**
  * spmi_controller_alloc() - Allocate a new SPMI device
  * @ctrl:	associated controller
  *
  * Caller is responsible for either calling spmi_device_add() to add the
  * newly allocated controller, or calling spmi_device_put() to discard it.
  */
 struct spmi_device *spmi_device_alloc(struct spmi_controller *ctrl)
 {
 	struct spmi_device *sdev;

 	sdev = kzalloc(sizeof(*sdev), GFP_KERNEL);
 	if (!sdev)
 		return NULL;

 	sdev->ctrl = ctrl;
 	device_initialize(&sdev->dev);
 	sdev->dev.parent = &ctrl->dev;
 	sdev->dev.bus = &spmi_bus_type;
 	sdev->dev.type = &spmi_dev_type;
 	return sdev;
 }
 EXPORT_SYMBOL_GPL(spmi_device_alloc);

 /**
  * spmi_controller_alloc() - Allocate a new SPMI controller
  * @parent:	parent device
  * @size:	size of private data
  *
  * Caller is responsible for either calling spmi_controller_add() to add the
  * newly allocated controller, or calling spmi_controller_put() to discard it.
  * The allocated private data region may be accessed via
  * spmi_controller_get_drvdata()
  */
 struct spmi_controller *spmi_controller_alloc(struct device *parent,
 					      size_t size)
 {
 	struct spmi_controller *ctrl;
 	int id;

 	if (WARN_ON(!parent))
 		return NULL;

 	ctrl = kzalloc(sizeof(*ctrl) + size, GFP_KERNEL);
 	if (!ctrl)
 		return NULL;

 	device_initialize(&ctrl->dev);
 	ctrl->dev.type = &spmi_ctrl_type;
 	ctrl->dev.bus = &spmi_bus_type;
 	ctrl->dev.parent = parent;
 	ctrl->dev.of_node = parent->of_node;
 	spmi_controller_set_drvdata(ctrl, &ctrl[1]);

 	id = ida_simple_get(&ctrl_ida, 0, 0, GFP_KERNEL);
 	if (id < 0) {
 		dev_err(parent,
 			"unable to allocate SPMI controller identifier.\n");
 		spmi_controller_put(ctrl);
 		return NULL;
 	}

 	ctrl->nr = id;
 	dev_set_name(&ctrl->dev, "spmi-%d", id);

 	dev_dbg(&ctrl->dev, "allocated controller 0x%p id %d\n", ctrl, id);
 	return ctrl;
 }
 EXPORT_SYMBOL_GPL(spmi_controller_alloc);

 static void of_spmi_register_devices(struct spmi_controller *ctrl)
 {
 	struct device_node *node;
 	int err;

 	if (!ctrl->dev.of_node)
 		return;

 	for_each_available_child_of_node(ctrl->dev.of_node, node) {
 		struct spmi_device *sdev;
 		u32 reg[2];

 		dev_dbg(&ctrl->dev, "adding child %pOF\n", node);

 		err = of_property_read_u32_array(node, "reg", reg, 2);
 		if (err) {
 			dev_err(&ctrl->dev,
 				"node %pOF err (%d) does not have 'reg' property\n",
 				node, err);
 			continue;
 		}

 		if (reg[1] != SPMI_USID) {
 			dev_err(&ctrl->dev,
 				"node %pOF contains unsupported 'reg' entry\n",
 				node);
 			continue;
 		}

 		if (reg[0] >= SPMI_MAX_SLAVE_ID) {
 			dev_err(&ctrl->dev, "invalid usid on node %pOF\n", node);
 			continue;
 		}

 		dev_dbg(&ctrl->dev, "read usid %02x\n", reg[0]);

 		sdev = spmi_device_alloc(ctrl);
 		if (!sdev)
 			continue;

 		sdev->dev.of_node = node;
 		sdev->usid = (u8) reg[0];

 		err = spmi_device_add(sdev);
 		if (err) {
 			dev_err(&sdev->dev,
 				"failure adding device. status %d\n", err);
 			spmi_device_put(sdev);
 		}
 	}
 }

 /**
  * spmi_controller_add() - Add an SPMI controller
  * @ctrl:	controller to be registered.
  *
  * Register a controller previously allocated via spmi_controller_alloc() with
  * the SPMI core.
  */
 int spmi_controller_add(struct spmi_controller *ctrl)
 {
 	int ret;

 	/* Can't register until after driver model init */
 	if (WARN_ON(!is_registered))
 		return -EAGAIN;

 	ret = device_add(&ctrl->dev);
 	if (ret)
 		return ret;

 	if (IS_ENABLED(CONFIG_OF))
 		of_spmi_register_devices(ctrl);

 	dev_dbg(&ctrl->dev, "spmi-%d registered: dev:%p\n",
 		ctrl->nr, &ctrl->dev);

 	return 0;
 };
 EXPORT_SYMBOL_GPL(spmi_controller_add);

 /* Remove a device associated with a controller */
 static int spmi_ctrl_remove_device(struct device *dev, void *data)
 {
 	struct spmi_device *spmidev = to_spmi_device(dev);
 	if (dev->type == &spmi_dev_type)
 		spmi_device_remove(spmidev);
 	return 0;
 }

 /**
  * spmi_controller_remove(): remove an SPMI controller
  * @ctrl:	controller to remove
  *
  * Remove a SPMI controller.  Caller is responsible for calling
  * spmi_controller_put() to discard the allocated controller.
  */
 void spmi_controller_remove(struct spmi_controller *ctrl)
 {
 	int dummy;

 	if (!ctrl)
 		return;

 	dummy = device_for_each_child(&ctrl->dev, NULL,
 				      spmi_ctrl_remove_device);
 	device_del(&ctrl->dev);
 }
 EXPORT_SYMBOL_GPL(spmi_controller_remove);

 /**
  * spmi_driver_register() - Register client driver with SPMI core
  * @sdrv:	client driver to be associated with client-device.
  *
  * This API will register the client driver with the SPMI framework.
  * It is typically called from the driver's module-init function.
  */
 int __spmi_driver_register(struct spmi_driver *sdrv, struct module *owner)
 {
 	sdrv->driver.bus = &spmi_bus_type;
 	sdrv->driver.owner = owner;
 	return driver_register(&sdrv->driver);
 }
 EXPORT_SYMBOL_GPL(__spmi_driver_register);

 static void __exit spmi_exit(void)
 {
 	bus_unregister(&spmi_bus_type);
 }
 module_exit(spmi_exit);

 static int __init spmi_init(void)
 {
 	int ret;

 	ret = bus_register(&spmi_bus_type);
 	if (ret)
 		return ret;

 	is_registered = true;
 	return 0;
 }
 postcore_initcall(spmi_init);

 MODULE_LICENSE("GPL v2");
 MODULE_DESCRIPTION("SPMI module");
 MODULE_ALIAS("platform:spmi");
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	* Copyright (c) 2012-2015, The Linux Foundation. All rights reserved.
	*/
	#include <linux/kernel.h>
	#include <linux/errno.h>
	#include <linux/idr.h>
	#include <linux/slab.h>
	#include <linux/module.h>
	#include <linux/of.h>
	#include <linux/of_device.h>
	#include <linux/platform_device.h>
	#include <linux/spmi.h>
	#include <linux/pm_runtime.h>

	#include <dt-bindings/spmi/spmi.h>
	#define CREATE_TRACE_POINTS
	#include <trace/events/spmi.h>

	static bool is_registered;
	static DEFINE_IDA(ctrl_ida);

	static void spmi_dev_release(struct device *dev)
	{
	struct spmi_device *sdev = to_spmi_device(dev);
	kfree(sdev);
	}

	static const struct device_type spmi_dev_type = {
	.release = spmi_dev_release,
	};

	static void spmi_ctrl_release(struct device *dev)
	{
	struct spmi_controller *ctrl = to_spmi_controller(dev);
	ida_simple_remove(&ctrl_ida, ctrl->nr);
	kfree(ctrl);
	}

	static const struct device_type spmi_ctrl_type = {
	.release = spmi_ctrl_release,
	};

	static int spmi_device_match(struct device dev, struct device_driver drv)
	{
	if (of_driver_match_device(dev, drv))
	return 1;

	if (drv->name)
	return strncmp(dev_name(dev), drv->name,
	SPMI_NAME_SIZE) == 0;

	return 0;
	}

	/**
	* spmi_device_add() - add a device previously constructed via spmi_device_alloc()
	* @sdev: spmi_device to be added
	*/
	int spmi_device_add(struct spmi_device *sdev)
	{
	struct spmi_controller *ctrl = sdev->ctrl;
	int err;

	dev_set_name(&sdev->dev, "%d-%02x", ctrl->nr, sdev->usid);

	err = device_add(&sdev->dev);
	if (err < 0) {
	dev_err(&sdev->dev, "Can't add %s, status %d\n",
	dev_name(&sdev->dev), err);
	goto err_device_add;
	}

	dev_dbg(&sdev->dev, "device %s registered\n", dev_name(&sdev->dev));

	err_device_add:
	return err;
	}
	EXPORT_SYMBOL_GPL(spmi_device_add);

	/**
	* spmi_device_remove(): remove an SPMI device
	* @sdev: spmi_device to be removed
	*/
	void spmi_device_remove(struct spmi_device *sdev)
	{
	device_unregister(&sdev->dev);
	}
	EXPORT_SYMBOL_GPL(spmi_device_remove);

	static inline int
	spmi_cmd(struct spmi_controller *ctrl, u8 opcode, u8 sid)
	{
	int ret;

	if (!ctrl \|\| !ctrl->cmd \|\| ctrl->dev.type != &spmi_ctrl_type)
	return -EINVAL;

	ret = ctrl->cmd(ctrl, opcode, sid);
	trace_spmi_cmd(opcode, sid, ret);
	return ret;
	}

	static inline int spmi_read_cmd(struct spmi_controller *ctrl, u8 opcode,
	u8 sid, u16 addr, u8 *buf, size_t len)
	{
	int ret;

	if (!ctrl \|\| !ctrl->read_cmd \|\| ctrl->dev.type != &spmi_ctrl_type)
	return -EINVAL;

	trace_spmi_read_begin(opcode, sid, addr);
	ret = ctrl->read_cmd(ctrl, opcode, sid, addr, buf, len);
	trace_spmi_read_end(opcode, sid, addr, ret, len, buf);
	return ret;
	}

	static inline int spmi_write_cmd(struct spmi_controller *ctrl, u8 opcode,
	u8 sid, u16 addr, const u8 *buf, size_t len)
	{
	int ret;

	if (!ctrl \|\| !ctrl->write_cmd \|\| ctrl->dev.type != &spmi_ctrl_type)
	return -EINVAL;

	trace_spmi_write_begin(opcode, sid, addr, len, buf);
	ret = ctrl->write_cmd(ctrl, opcode, sid, addr, buf, len);
	trace_spmi_write_end(opcode, sid, addr, ret);
	return ret;
	}

	/**
	* spmi_register_read() - register read
	* @sdev: SPMI device.
	* @addr: slave register address (5-bit address).
	* @buf: buffer to be populated with data from the Slave.
	*
	* Reads 1 byte of data from a Slave device register.
	*/
	int spmi_register_read(struct spmi_device sdev, u8 addr, u8 buf)
	{
	/* 5-bit register address */
	if (addr > 0x1F)
	return -EINVAL;

	return spmi_read_cmd(sdev->ctrl, SPMI_CMD_READ, sdev->usid, addr,
	buf, 1);
	}
	EXPORT_SYMBOL_GPL(spmi_register_read);

	/**
	* spmi_ext_register_read() - extended register read
	* @sdev: SPMI device.
	* @addr: slave register address (8-bit address).
	* @buf: buffer to be populated with data from the Slave.
	* @len: the request number of bytes to read (up to 16 bytes).
	*
	* Reads up to 16 bytes of data from the extended register space on a
	* Slave device.
	*/
	int spmi_ext_register_read(struct spmi_device sdev, u8 addr, u8 buf,
	size_t len)
	{
	/* 8-bit register address, up to 16 bytes */
	if (len == 0 \|\| len > 16)
	return -EINVAL;

	return spmi_read_cmd(sdev->ctrl, SPMI_CMD_EXT_READ, sdev->usid, addr,
	buf, len);
	}
	EXPORT_SYMBOL_GPL(spmi_ext_register_read);

	/**
	* spmi_ext_register_readl() - extended register read long
	* @sdev: SPMI device.
	* @addr: slave register address (16-bit address).
	* @buf: buffer to be populated with data from the Slave.
	* @len: the request number of bytes to read (up to 8 bytes).
	*
	* Reads up to 8 bytes of data from the extended register space on a
	* Slave device using 16-bit address.
	*/
	int spmi_ext_register_readl(struct spmi_device sdev, u16 addr, u8 buf,
	size_t len)
	{
	/* 16-bit register address, up to 8 bytes */
	if (len == 0 \|\| len > 8)
	return -EINVAL;

	return spmi_read_cmd(sdev->ctrl, SPMI_CMD_EXT_READL, sdev->usid, addr,
	buf, len);
	}
	EXPORT_SYMBOL_GPL(spmi_ext_register_readl);

	/**
	* spmi_register_write() - register write
	* @sdev: SPMI device
	* @addr: slave register address (5-bit address).
	* @data: buffer containing the data to be transferred to the Slave.
	*
	* Writes 1 byte of data to a Slave device register.
	*/
	int spmi_register_write(struct spmi_device *sdev, u8 addr, u8 data)
	{
	/* 5-bit register address */
	if (addr > 0x1F)
	return -EINVAL;

	return spmi_write_cmd(sdev->ctrl, SPMI_CMD_WRITE, sdev->usid, addr,
	&data, 1);
	}
	EXPORT_SYMBOL_GPL(spmi_register_write);

	/**
	* spmi_register_zero_write() - register zero write
	* @sdev: SPMI device.
	* @data: the data to be written to register 0 (7-bits).
	*
	* Writes data to register 0 of the Slave device.
	*/
	int spmi_register_zero_write(struct spmi_device *sdev, u8 data)
	{
	return spmi_write_cmd(sdev->ctrl, SPMI_CMD_ZERO_WRITE, sdev->usid, 0,
	&data, 1);
	}
	EXPORT_SYMBOL_GPL(spmi_register_zero_write);

	/**
	* spmi_ext_register_write() - extended register write
	* @sdev: SPMI device.
	* @addr: slave register address (8-bit address).
	* @buf: buffer containing the data to be transferred to the Slave.
	* @len: the request number of bytes to read (up to 16 bytes).
	*
	* Writes up to 16 bytes of data to the extended register space of a
	* Slave device.
	*/
	int spmi_ext_register_write(struct spmi_device sdev, u8 addr, const u8 buf,
	size_t len)
	{
	/* 8-bit register address, up to 16 bytes */
	if (len == 0 \|\| len > 16)
	return -EINVAL;

	return spmi_write_cmd(sdev->ctrl, SPMI_CMD_EXT_WRITE, sdev->usid, addr,
	buf, len);
	}
	EXPORT_SYMBOL_GPL(spmi_ext_register_write);

	/**
	* spmi_ext_register_writel() - extended register write long
	* @sdev: SPMI device.
	* @addr: slave register address (16-bit address).
	* @buf: buffer containing the data to be transferred to the Slave.
	* @len: the request number of bytes to read (up to 8 bytes).
	*
	* Writes up to 8 bytes of data to the extended register space of a
	* Slave device using 16-bit address.
	*/
	int spmi_ext_register_writel(struct spmi_device sdev, u16 addr, const u8 buf,
	size_t len)
	{
	/* 4-bit Slave Identifier, 16-bit register address, up to 8 bytes */
	if (len == 0 \|\| len > 8)
	return -EINVAL;

	return spmi_write_cmd(sdev->ctrl, SPMI_CMD_EXT_WRITEL, sdev->usid,
	addr, buf, len);
	}
	EXPORT_SYMBOL_GPL(spmi_ext_register_writel);

	/**
	* spmi_command_reset() - sends RESET command to the specified slave
	* @sdev: SPMI device.
	*
	* The Reset command initializes the Slave and forces all registers to
	* their reset values. The Slave shall enter the STARTUP state after
	* receiving a Reset command.
	*/
	int spmi_command_reset(struct spmi_device *sdev)
	{
	return spmi_cmd(sdev->ctrl, SPMI_CMD_RESET, sdev->usid);
	}
	EXPORT_SYMBOL_GPL(spmi_command_reset);

	/**
	* spmi_command_sleep() - sends SLEEP command to the specified SPMI device
	* @sdev: SPMI device.
	*
	* The Sleep command causes the Slave to enter the user defined SLEEP state.
	*/
	int spmi_command_sleep(struct spmi_device *sdev)
	{
	return spmi_cmd(sdev->ctrl, SPMI_CMD_SLEEP, sdev->usid);
	}
	EXPORT_SYMBOL_GPL(spmi_command_sleep);

	/**
	* spmi_command_wakeup() - sends WAKEUP command to the specified SPMI device
	* @sdev: SPMI device.
	*
	* The Wakeup command causes the Slave to move from the SLEEP state to
	* the ACTIVE state.
	*/
	int spmi_command_wakeup(struct spmi_device *sdev)
	{
	return spmi_cmd(sdev->ctrl, SPMI_CMD_WAKEUP, sdev->usid);
	}
	EXPORT_SYMBOL_GPL(spmi_command_wakeup);

	/**
	* spmi_command_shutdown() - sends SHUTDOWN command to the specified SPMI device
	* @sdev: SPMI device.
	*
	* The Shutdown command causes the Slave to enter the SHUTDOWN state.
	*/
	int spmi_command_shutdown(struct spmi_device *sdev)
	{
	return spmi_cmd(sdev->ctrl, SPMI_CMD_SHUTDOWN, sdev->usid);
	}
	EXPORT_SYMBOL_GPL(spmi_command_shutdown);

	static int spmi_drv_probe(struct device *dev)
	{
	const struct spmi_driver *sdrv = to_spmi_driver(dev->driver);
	struct spmi_device *sdev = to_spmi_device(dev);
	int err;

	pm_runtime_get_noresume(dev);
	pm_runtime_set_active(dev);
	pm_runtime_enable(dev);

	err = sdrv->probe(sdev);
	if (err)
	goto fail_probe;

	return 0;

	fail_probe:
	pm_runtime_disable(dev);
	pm_runtime_set_suspended(dev);
	pm_runtime_put_noidle(dev);
	return err;
	}

	static int spmi_drv_remove(struct device *dev)
	{
	const struct spmi_driver *sdrv = to_spmi_driver(dev->driver);

	pm_runtime_get_sync(dev);
	sdrv->remove(to_spmi_device(dev));
	pm_runtime_put_noidle(dev);

	pm_runtime_disable(dev);
	pm_runtime_set_suspended(dev);
	pm_runtime_put_noidle(dev);
	return 0;
	}

	static int spmi_drv_uevent(struct device dev, struct kobj_uevent_env env)
	{
	int ret;

	ret = of_device_uevent_modalias(dev, env);
	if (ret != -ENODEV)
	return ret;

	return 0;
	}

	static struct bus_type spmi_bus_type = {
	.name = "spmi",
	.match = spmi_device_match,
	.probe = spmi_drv_probe,
	.remove = spmi_drv_remove,
	.uevent = spmi_drv_uevent,
	};

	/**
	* spmi_controller_alloc() - Allocate a new SPMI device
	* @ctrl: associated controller
	*
	* Caller is responsible for either calling spmi_device_add() to add the
	* newly allocated controller, or calling spmi_device_put() to discard it.
	*/
	struct spmi_device spmi_device_alloc(struct spmi_controller ctrl)
	{
	struct spmi_device *sdev;

	sdev = kzalloc(sizeof(*sdev), GFP_KERNEL);
	if (!sdev)
	return NULL;

	sdev->ctrl = ctrl;
	device_initialize(&sdev->dev);
	sdev->dev.parent = &ctrl->dev;
	sdev->dev.bus = &spmi_bus_type;
	sdev->dev.type = &spmi_dev_type;
	return sdev;
	}
	EXPORT_SYMBOL_GPL(spmi_device_alloc);

	/**
	* spmi_controller_alloc() - Allocate a new SPMI controller
	* @parent: parent device
	* @size: size of private data
	*
	* Caller is responsible for either calling spmi_controller_add() to add the
	* newly allocated controller, or calling spmi_controller_put() to discard it.
	* The allocated private data region may be accessed via
	* spmi_controller_get_drvdata()
	*/
	struct spmi_controller spmi_controller_alloc(struct device parent,
	size_t size)
	{
	struct spmi_controller *ctrl;
	int id;

	if (WARN_ON(!parent))
	return NULL;

	ctrl = kzalloc(sizeof(*ctrl) + size, GFP_KERNEL);
	if (!ctrl)
	return NULL;

	device_initialize(&ctrl->dev);
	ctrl->dev.type = &spmi_ctrl_type;
	ctrl->dev.bus = &spmi_bus_type;
	ctrl->dev.parent = parent;
	ctrl->dev.of_node = parent->of_node;
	spmi_controller_set_drvdata(ctrl, &ctrl[1]);

	id = ida_simple_get(&ctrl_ida, 0, 0, GFP_KERNEL);
	if (id < 0) {
	dev_err(parent,
	"unable to allocate SPMI controller identifier.\n");
	spmi_controller_put(ctrl);
	return NULL;
	}

	ctrl->nr = id;
	dev_set_name(&ctrl->dev, "spmi-%d", id);

	dev_dbg(&ctrl->dev, "allocated controller 0x%p id %d\n", ctrl, id);
	return ctrl;
	}
	EXPORT_SYMBOL_GPL(spmi_controller_alloc);

	static void of_spmi_register_devices(struct spmi_controller *ctrl)
	{
	struct device_node *node;
	int err;

	if (!ctrl->dev.of_node)
	return;

	for_each_available_child_of_node(ctrl->dev.of_node, node) {
	struct spmi_device *sdev;
	u32 reg[2];

	dev_dbg(&ctrl->dev, "adding child %pOF\n", node);

	err = of_property_read_u32_array(node, "reg", reg, 2);
	if (err) {
	dev_err(&ctrl->dev,
	"node %pOF err (%d) does not have 'reg' property\n",
	node, err);
	continue;
	}

	if (reg[1] != SPMI_USID) {
	dev_err(&ctrl->dev,
	"node %pOF contains unsupported 'reg' entry\n",
	node);
	continue;
	}

	if (reg[0] >= SPMI_MAX_SLAVE_ID) {
	dev_err(&ctrl->dev, "invalid usid on node %pOF\n", node);
	continue;
	}

	dev_dbg(&ctrl->dev, "read usid %02x\n", reg[0]);

	sdev = spmi_device_alloc(ctrl);
	if (!sdev)
	continue;

	sdev->dev.of_node = node;
	sdev->usid = (u8) reg[0];

	err = spmi_device_add(sdev);
	if (err) {
	dev_err(&sdev->dev,
	"failure adding device. status %d\n", err);
	spmi_device_put(sdev);
	}
	}
	}

	/**
	* spmi_controller_add() - Add an SPMI controller
	* @ctrl: controller to be registered.
	*
	* Register a controller previously allocated via spmi_controller_alloc() with
	* the SPMI core.
	*/
	int spmi_controller_add(struct spmi_controller *ctrl)
	{
	int ret;

	/* Can't register until after driver model init */
	if (WARN_ON(!is_registered))
	return -EAGAIN;

	ret = device_add(&ctrl->dev);
	if (ret)
	return ret;

	if (IS_ENABLED(CONFIG_OF))
	of_spmi_register_devices(ctrl);

	dev_dbg(&ctrl->dev, "spmi-%d registered: dev:%p\n",
	ctrl->nr, &ctrl->dev);

	return 0;
	};
	EXPORT_SYMBOL_GPL(spmi_controller_add);

	/* Remove a device associated with a controller */
	static int spmi_ctrl_remove_device(struct device dev, void data)
	{
	struct spmi_device *spmidev = to_spmi_device(dev);
	if (dev->type == &spmi_dev_type)
	spmi_device_remove(spmidev);
	return 0;
	}

	/**
	* spmi_controller_remove(): remove an SPMI controller
	* @ctrl: controller to remove
	*
	* Remove a SPMI controller. Caller is responsible for calling
	* spmi_controller_put() to discard the allocated controller.
	*/
	void spmi_controller_remove(struct spmi_controller *ctrl)
	{
	int dummy;

	if (!ctrl)
	return;

	dummy = device_for_each_child(&ctrl->dev, NULL,
	spmi_ctrl_remove_device);
	device_del(&ctrl->dev);
	}
	EXPORT_SYMBOL_GPL(spmi_controller_remove);

	/**
	* spmi_driver_register() - Register client driver with SPMI core
	* @sdrv: client driver to be associated with client-device.
	*
	* This API will register the client driver with the SPMI framework.
	* It is typically called from the driver's module-init function.
	*/
	int __spmi_driver_register(struct spmi_driver sdrv, struct module owner)
	{
	sdrv->driver.bus = &spmi_bus_type;
	sdrv->driver.owner = owner;
	return driver_register(&sdrv->driver);
	}
	EXPORT_SYMBOL_GPL(__spmi_driver_register);

	static void __exit spmi_exit(void)
	{
	bus_unregister(&spmi_bus_type);
	}
	module_exit(spmi_exit);

	static int __init spmi_init(void)
	{
	int ret;

	ret = bus_register(&spmi_bus_type);
	if (ret)
	return ret;

	is_registered = true;
	return 0;
	}
	postcore_initcall(spmi_init);

	MODULE_LICENSE("GPL v2");
	MODULE_DESCRIPTION("SPMI module");
	MODULE_ALIAS("platform:spmi");