drivers/input/mouse/psmouse-smbus.c - kernel/msm-5.4 - Gitiles

 /*
  * Copyright (c) 2017 Red Hat, Inc
  *
  * This program is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License version 2 as published by
  * the Free Software Foundation.
  */

 #define pr_fmt(fmt)		KBUILD_MODNAME ": " fmt

 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/libps2.h>
 #include <linux/i2c.h>
 #include <linux/serio.h>
 #include <linux/slab.h>
 #include <linux/workqueue.h>
 #include "psmouse.h"

 struct psmouse_smbus_dev {
 	struct i2c_board_info board;
 	struct psmouse *psmouse;
 	struct i2c_client *client;
 	struct list_head node;
 	bool dead;
 };

 static LIST_HEAD(psmouse_smbus_list);
 static DEFINE_MUTEX(psmouse_smbus_mutex);

 static void psmouse_smbus_check_adapter(struct i2c_adapter *adapter)
 {
 	struct psmouse_smbus_dev *smbdev;

 	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_HOST_NOTIFY))
 		return;

 	mutex_lock(&psmouse_smbus_mutex);

 	list_for_each_entry(smbdev, &psmouse_smbus_list, node) {
 		if (smbdev->dead)
 			continue;

 		if (smbdev->client)
 			continue;

 		/*
 		 * Here would be a good place to check if device is actually
 		 * present, but it seems that SMBus will not respond unless we
 		 * fully reset PS/2 connection.  So cross our fingers, and try
 		 * to switch over, hopefully our system will not have too many
 		 * "host notify" I2C adapters.
 		 */
 		psmouse_dbg(smbdev->psmouse,
 			    "SMBus candidate adapter appeared, triggering rescan\n");
 		serio_rescan(smbdev->psmouse->ps2dev.serio);
 	}

 	mutex_unlock(&psmouse_smbus_mutex);
 }

 static void psmouse_smbus_detach_i2c_client(struct i2c_client *client)
 {
 	struct psmouse_smbus_dev *smbdev, *tmp;

 	mutex_lock(&psmouse_smbus_mutex);

 	list_for_each_entry_safe(smbdev, tmp, &psmouse_smbus_list, node) {
 		if (smbdev->client != client)
 			continue;

 		kfree(client->dev.platform_data);
 		client->dev.platform_data = NULL;

 		if (!smbdev->dead) {
 			psmouse_dbg(smbdev->psmouse,
 				    "Marking SMBus companion %s as gone\n",
 				    dev_name(&smbdev->client->dev));
 			smbdev->dead = true;
 			serio_rescan(smbdev->psmouse->ps2dev.serio);
 		} else {
 			list_del(&smbdev->node);
 			kfree(smbdev);
 		}
 	}

 	mutex_unlock(&psmouse_smbus_mutex);
 }

 static int psmouse_smbus_notifier_call(struct notifier_block *nb,
 				       unsigned long action, void *data)
 {
 	struct device *dev = data;

 	switch (action) {
 	case BUS_NOTIFY_ADD_DEVICE:
 		if (dev->type == &i2c_adapter_type)
 			psmouse_smbus_check_adapter(to_i2c_adapter(dev));
 		break;

 	case BUS_NOTIFY_REMOVED_DEVICE:
 		if (dev->type == &i2c_client_type)
 			psmouse_smbus_detach_i2c_client(to_i2c_client(dev));
 		break;
 	}

 	return 0;
 }

 static struct notifier_block psmouse_smbus_notifier = {
 	.notifier_call = psmouse_smbus_notifier_call,
 };

 static psmouse_ret_t psmouse_smbus_process_byte(struct psmouse *psmouse)
 {
 	return PSMOUSE_FULL_PACKET;
 }

 static int psmouse_smbus_reconnect(struct psmouse *psmouse)
 {
 	psmouse_deactivate(psmouse);

 	return 0;
 }

 struct psmouse_smbus_removal_work {
 	struct work_struct work;
 	struct i2c_client *client;
 };

 static void psmouse_smbus_remove_i2c_device(struct work_struct *work)
 {
 	struct psmouse_smbus_removal_work *rwork =
 		container_of(work, struct psmouse_smbus_removal_work, work);

 	dev_dbg(&rwork->client->dev, "destroying SMBus companion device\n");
 	i2c_unregister_device(rwork->client);

 	kfree(rwork);
 }

 /*
  * This schedules removal of SMBus companion device. We have to do
  * it in a separate tread to avoid deadlocking on psmouse_mutex in
  * case the device has a trackstick (which is also driven by psmouse).
  *
  * Note that this may be racing with i2c adapter removal, but we
  * can't do anything about that: i2c automatically destroys clients
  * attached to an adapter that is being removed. This has to be
  * fixed in i2c core.
  */
 static void psmouse_smbus_schedule_remove(struct i2c_client *client)
 {
 	struct psmouse_smbus_removal_work *rwork;

 	rwork = kzalloc(sizeof(*rwork), GFP_KERNEL);
 	if (rwork) {
 		INIT_WORK(&rwork->work, psmouse_smbus_remove_i2c_device);
 		rwork->client = client;

 		schedule_work(&rwork->work);
 	}
 }

 static void psmouse_smbus_disconnect(struct psmouse *psmouse)
 {
 	struct psmouse_smbus_dev *smbdev = psmouse->private;

 	mutex_lock(&psmouse_smbus_mutex);

 	if (smbdev->dead) {
 		list_del(&smbdev->node);
 		kfree(smbdev);
 	} else {
 		smbdev->dead = true;
 		psmouse_dbg(smbdev->psmouse,
 			    "posting removal request for SMBus companion %s\n",
 			    dev_name(&smbdev->client->dev));
 		psmouse_smbus_schedule_remove(smbdev->client);
 	}

 	mutex_unlock(&psmouse_smbus_mutex);

 	psmouse->private = NULL;
 }

 static int psmouse_smbus_create_companion(struct device *dev, void *data)
 {
 	struct psmouse_smbus_dev *smbdev = data;
 	unsigned short addr_list[] = { smbdev->board.addr, I2C_CLIENT_END };
 	struct i2c_adapter *adapter;

 	adapter = i2c_verify_adapter(dev);
 	if (!adapter)
 		return 0;

 	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_HOST_NOTIFY))
 		return 0;

 	smbdev->client = i2c_new_probed_device(adapter, &smbdev->board,
 					       addr_list, NULL);
 	if (!smbdev->client)
 		return 0;

 	/* We have our(?) device, stop iterating i2c bus. */
 	return 1;
 }

 void psmouse_smbus_cleanup(struct psmouse *psmouse)
 {
 	struct psmouse_smbus_dev *smbdev, *tmp;

 	mutex_lock(&psmouse_smbus_mutex);

 	list_for_each_entry_safe(smbdev, tmp, &psmouse_smbus_list, node) {
 		if (psmouse == smbdev->psmouse) {
 			list_del(&smbdev->node);
 			kfree(smbdev);
 		}
 	}

 	mutex_unlock(&psmouse_smbus_mutex);
 }

 int psmouse_smbus_init(struct psmouse *psmouse,
 		       const struct i2c_board_info *board,
 		       const void *pdata, size_t pdata_size,
 		       bool leave_breadcrumbs)
 {
 	struct psmouse_smbus_dev *smbdev;
 	int error;

 	smbdev = kzalloc(sizeof(*smbdev), GFP_KERNEL);
 	if (!smbdev)
 		return -ENOMEM;

 	smbdev->psmouse = psmouse;
 	smbdev->board = *board;

 	if (pdata) {
 		smbdev->board.platform_data = kmemdup(pdata, pdata_size,
 						      GFP_KERNEL);
 		if (!smbdev->board.platform_data) {
 			kfree(smbdev);
 			return -ENOMEM;
 		}
 	}

 	psmouse->private = smbdev;
 	psmouse->protocol_handler = psmouse_smbus_process_byte;
 	psmouse->reconnect = psmouse_smbus_reconnect;
 	psmouse->fast_reconnect = psmouse_smbus_reconnect;
 	psmouse->disconnect = psmouse_smbus_disconnect;
 	psmouse->resync_time = 0;

 	psmouse_deactivate(psmouse);

 	mutex_lock(&psmouse_smbus_mutex);
 	list_add_tail(&smbdev->node, &psmouse_smbus_list);
 	mutex_unlock(&psmouse_smbus_mutex);

 	/* Bind to already existing adapters right away */
 	error = i2c_for_each_dev(smbdev, psmouse_smbus_create_companion);

 	if (smbdev->client) {
 		/* We have our companion device */
 		return 0;
 	}

 	/*
 	 * If we did not create i2c device we will not need platform
 	 * data even if we are leaving breadcrumbs.
 	 */
 	kfree(smbdev->board.platform_data);
 	smbdev->board.platform_data = NULL;

 	if (error < 0 || !leave_breadcrumbs) {
 		mutex_lock(&psmouse_smbus_mutex);
 		list_del(&smbdev->node);
 		mutex_unlock(&psmouse_smbus_mutex);

 		kfree(smbdev);
 	}

 	return error < 0 ? error : -EAGAIN;
 }

 int __init psmouse_smbus_module_init(void)
 {
 	int error;

 	error = bus_register_notifier(&i2c_bus_type, &psmouse_smbus_notifier);
 	if (error) {
 		pr_err("failed to register i2c bus notifier: %d\n", error);
 		return error;
 	}

 	return 0;
 }

 void psmouse_smbus_module_exit(void)
 {
 	bus_unregister_notifier(&i2c_bus_type, &psmouse_smbus_notifier);
 	flush_scheduled_work();
 }
	/*
	* Copyright (c) 2017 Red Hat, Inc
	*
	* This program is free software; you can redistribute it and/or modify it
	* under the terms of the GNU General Public License version 2 as published by
	* the Free Software Foundation.
	*/

	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

	#include <linux/kernel.h>
	#include <linux/module.h>
	#include <linux/libps2.h>
	#include <linux/i2c.h>
	#include <linux/serio.h>
	#include <linux/slab.h>
	#include <linux/workqueue.h>
	#include "psmouse.h"

	struct psmouse_smbus_dev {
	struct i2c_board_info board;
	struct psmouse *psmouse;
	struct i2c_client *client;
	struct list_head node;
	bool dead;
	};

	static LIST_HEAD(psmouse_smbus_list);
	static DEFINE_MUTEX(psmouse_smbus_mutex);

	static void psmouse_smbus_check_adapter(struct i2c_adapter *adapter)
	{
	struct psmouse_smbus_dev *smbdev;

	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_HOST_NOTIFY))
	return;

	mutex_lock(&psmouse_smbus_mutex);

	list_for_each_entry(smbdev, &psmouse_smbus_list, node) {
	if (smbdev->dead)
	continue;

	if (smbdev->client)
	continue;

	/*
	* Here would be a good place to check if device is actually
	* present, but it seems that SMBus will not respond unless we
	* fully reset PS/2 connection. So cross our fingers, and try
	* to switch over, hopefully our system will not have too many
	* "host notify" I2C adapters.
	*/
	psmouse_dbg(smbdev->psmouse,
	"SMBus candidate adapter appeared, triggering rescan\n");
	serio_rescan(smbdev->psmouse->ps2dev.serio);
	}

	mutex_unlock(&psmouse_smbus_mutex);
	}

	static void psmouse_smbus_detach_i2c_client(struct i2c_client *client)
	{
	struct psmouse_smbus_dev smbdev, tmp;

	mutex_lock(&psmouse_smbus_mutex);

	list_for_each_entry_safe(smbdev, tmp, &psmouse_smbus_list, node) {
	if (smbdev->client != client)
	continue;

	kfree(client->dev.platform_data);
	client->dev.platform_data = NULL;

	if (!smbdev->dead) {
	psmouse_dbg(smbdev->psmouse,
	"Marking SMBus companion %s as gone\n",
	dev_name(&smbdev->client->dev));
	smbdev->dead = true;
	serio_rescan(smbdev->psmouse->ps2dev.serio);
	} else {
	list_del(&smbdev->node);
	kfree(smbdev);
	}
	}

	mutex_unlock(&psmouse_smbus_mutex);
	}

	static int psmouse_smbus_notifier_call(struct notifier_block *nb,
	unsigned long action, void *data)
	{
	struct device *dev = data;

	switch (action) {
	case BUS_NOTIFY_ADD_DEVICE:
	if (dev->type == &i2c_adapter_type)
	psmouse_smbus_check_adapter(to_i2c_adapter(dev));
	break;

	case BUS_NOTIFY_REMOVED_DEVICE:
	if (dev->type == &i2c_client_type)
	psmouse_smbus_detach_i2c_client(to_i2c_client(dev));
	break;
	}

	return 0;
	}

	static struct notifier_block psmouse_smbus_notifier = {
	.notifier_call = psmouse_smbus_notifier_call,
	};

	static psmouse_ret_t psmouse_smbus_process_byte(struct psmouse *psmouse)
	{
	return PSMOUSE_FULL_PACKET;
	}

	static int psmouse_smbus_reconnect(struct psmouse *psmouse)
	{
	psmouse_deactivate(psmouse);

	return 0;
	}

	struct psmouse_smbus_removal_work {
	struct work_struct work;
	struct i2c_client *client;
	};

	static void psmouse_smbus_remove_i2c_device(struct work_struct *work)
	{
	struct psmouse_smbus_removal_work *rwork =
	container_of(work, struct psmouse_smbus_removal_work, work);

	dev_dbg(&rwork->client->dev, "destroying SMBus companion device\n");
	i2c_unregister_device(rwork->client);

	kfree(rwork);
	}

	/*
	* This schedules removal of SMBus companion device. We have to do
	* it in a separate tread to avoid deadlocking on psmouse_mutex in
	* case the device has a trackstick (which is also driven by psmouse).
	*
	* Note that this may be racing with i2c adapter removal, but we
	* can't do anything about that: i2c automatically destroys clients
	* attached to an adapter that is being removed. This has to be
	* fixed in i2c core.
	*/
	static void psmouse_smbus_schedule_remove(struct i2c_client *client)
	{
	struct psmouse_smbus_removal_work *rwork;

	rwork = kzalloc(sizeof(*rwork), GFP_KERNEL);
	if (rwork) {
	INIT_WORK(&rwork->work, psmouse_smbus_remove_i2c_device);
	rwork->client = client;

	schedule_work(&rwork->work);
	}
	}

	static void psmouse_smbus_disconnect(struct psmouse *psmouse)
	{
	struct psmouse_smbus_dev *smbdev = psmouse->private;

	mutex_lock(&psmouse_smbus_mutex);

	if (smbdev->dead) {
	list_del(&smbdev->node);
	kfree(smbdev);
	} else {
	smbdev->dead = true;
	psmouse_dbg(smbdev->psmouse,
	"posting removal request for SMBus companion %s\n",
	dev_name(&smbdev->client->dev));
	psmouse_smbus_schedule_remove(smbdev->client);
	}

	mutex_unlock(&psmouse_smbus_mutex);

	psmouse->private = NULL;
	}

	static int psmouse_smbus_create_companion(struct device dev, void data)
	{
	struct psmouse_smbus_dev *smbdev = data;
	unsigned short addr_list[] = { smbdev->board.addr, I2C_CLIENT_END };
	struct i2c_adapter *adapter;

	adapter = i2c_verify_adapter(dev);
	if (!adapter)
	return 0;

	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_HOST_NOTIFY))
	return 0;

	smbdev->client = i2c_new_probed_device(adapter, &smbdev->board,
	addr_list, NULL);
	if (!smbdev->client)
	return 0;

	/* We have our(?) device, stop iterating i2c bus. */
	return 1;
	}

	void psmouse_smbus_cleanup(struct psmouse *psmouse)
	{
	struct psmouse_smbus_dev smbdev, tmp;

	mutex_lock(&psmouse_smbus_mutex);

	list_for_each_entry_safe(smbdev, tmp, &psmouse_smbus_list, node) {
	if (psmouse == smbdev->psmouse) {
	list_del(&smbdev->node);
	kfree(smbdev);
	}
	}

	mutex_unlock(&psmouse_smbus_mutex);
	}

	int psmouse_smbus_init(struct psmouse *psmouse,
	const struct i2c_board_info *board,
	const void *pdata, size_t pdata_size,
	bool leave_breadcrumbs)
	{
	struct psmouse_smbus_dev *smbdev;
	int error;

	smbdev = kzalloc(sizeof(*smbdev), GFP_KERNEL);
	if (!smbdev)
	return -ENOMEM;

	smbdev->psmouse = psmouse;
	smbdev->board = *board;

	if (pdata) {
	smbdev->board.platform_data = kmemdup(pdata, pdata_size,
	GFP_KERNEL);
	if (!smbdev->board.platform_data) {
	kfree(smbdev);
	return -ENOMEM;
	}
	}

	psmouse->private = smbdev;
	psmouse->protocol_handler = psmouse_smbus_process_byte;
	psmouse->reconnect = psmouse_smbus_reconnect;
	psmouse->fast_reconnect = psmouse_smbus_reconnect;
	psmouse->disconnect = psmouse_smbus_disconnect;
	psmouse->resync_time = 0;

	psmouse_deactivate(psmouse);

	mutex_lock(&psmouse_smbus_mutex);
	list_add_tail(&smbdev->node, &psmouse_smbus_list);
	mutex_unlock(&psmouse_smbus_mutex);

	/* Bind to already existing adapters right away */
	error = i2c_for_each_dev(smbdev, psmouse_smbus_create_companion);

	if (smbdev->client) {
	/* We have our companion device */
	return 0;
	}

	/*
	* If we did not create i2c device we will not need platform
	* data even if we are leaving breadcrumbs.
	*/
	kfree(smbdev->board.platform_data);
	smbdev->board.platform_data = NULL;

	if (error < 0 \|\| !leave_breadcrumbs) {
	mutex_lock(&psmouse_smbus_mutex);
	list_del(&smbdev->node);
	mutex_unlock(&psmouse_smbus_mutex);

	kfree(smbdev);
	}

	return error < 0 ? error : -EAGAIN;
	}

	int __init psmouse_smbus_module_init(void)
	{
	int error;

	error = bus_register_notifier(&i2c_bus_type, &psmouse_smbus_notifier);
	if (error) {
	pr_err("failed to register i2c bus notifier: %d\n", error);
	return error;
	}

	return 0;
	}

	void psmouse_smbus_module_exit(void)
	{
	bus_unregister_notifier(&i2c_bus_type, &psmouse_smbus_notifier);
	flush_scheduled_work();
	}