Input: synaptics-rmi4 - add I2C transport driver

	  required for all RMI4 device support.

	  If unsure, say Y.

config RMI4_I2C

	tristate "RMI4 I2C Support"

	depends on RMI4_CORE && I2C

	help

	  Say Y here if you want to support RMI4 devices connected to an I2C

	  bus.

	  If unsure, say Y.

obj-$(CONFIG_RMI4_CORE) += rmi_core.o

rmi_core-y := rmi_bus.o rmi_driver.o rmi_f01.o

# Transports

obj-$(CONFIG_RMI4_I2C) += rmi_i2c.o

/*

 * Copyright (c) 2011-2016 Synaptics Incorporated

 * Copyright (c) 2011 Unixphere

 *

 * 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.

 */

#include <linux/i2c.h>

#include <linux/rmi.h>

#include <linux/irq.h>

#include "rmi_driver.h"

#define BUFFER_SIZE_INCREMENT 32

/**

 * struct rmi_i2c_xport - stores information for i2c communication

 *

 * @xport: The transport interface structure

 *

 * @page_mutex: Locks current page to avoid changing pages in unexpected ways.

 * @page: Keeps track of the current virtual page

 *

 * @tx_buf: Buffer used for transmitting data to the sensor over i2c.

 * @tx_buf_size: Size of the buffer

 */

struct rmi_i2c_xport {

	struct rmi_transport_dev xport;

	struct i2c_client *client;

	struct mutex page_mutex;

	int page;

	int irq;

	u8 *tx_buf;

	size_t tx_buf_size;

};

#define RMI_PAGE_SELECT_REGISTER 0xff

#define RMI_I2C_PAGE(addr) (((addr) >> 8) & 0xff)

/*

 * rmi_set_page - Set RMI page

 * @xport: The pointer to the rmi_transport_dev struct

 * @page: The new page address.

 *

 * RMI devices have 16-bit addressing, but some of the transport

 * implementations (like SMBus) only have 8-bit addressing. So RMI implements

 * a page address at 0xff of every page so we can reliable page addresses

 * every 256 registers.

 *

 * The page_mutex lock must be held when this function is entered.

 *

 * Returns zero on success, non-zero on failure.

 */

static int rmi_set_page(struct rmi_i2c_xport *rmi_i2c, u8 page)

{

	struct i2c_client *client = rmi_i2c->client;

	u8 txbuf[2] = {RMI_PAGE_SELECT_REGISTER, page};

	int retval;

	retval = i2c_master_send(client, txbuf, sizeof(txbuf));

	if (retval != sizeof(txbuf)) {

		dev_err(&client->dev,

			"%s: set page failed: %d.", __func__, retval);

		return (retval < 0) ? retval : -EIO;

	}

	rmi_i2c->page = page;

	return 0;

}

static int rmi_i2c_write_block(struct rmi_transport_dev *xport, u16 addr,

			       const void *buf, size_t len)

{

	struct rmi_i2c_xport *rmi_i2c =

		container_of(xport, struct rmi_i2c_xport, xport);

	struct i2c_client *client = rmi_i2c->client;

	size_t tx_size = len + 1;

	int retval;

	mutex_lock(&rmi_i2c->page_mutex);

	if (!rmi_i2c->tx_buf || rmi_i2c->tx_buf_size < tx_size) {

		if (rmi_i2c->tx_buf)

			devm_kfree(&client->dev, rmi_i2c->tx_buf);

		rmi_i2c->tx_buf_size = tx_size + BUFFER_SIZE_INCREMENT;

		rmi_i2c->tx_buf = devm_kzalloc(&client->dev,

					       rmi_i2c->tx_buf_size,

					       GFP_KERNEL);

		if (!rmi_i2c->tx_buf) {

			rmi_i2c->tx_buf_size = 0;

			retval = -ENOMEM;

			goto exit;

		}

	}

	rmi_i2c->tx_buf[0] = addr & 0xff;

	memcpy(rmi_i2c->tx_buf + 1, buf, len);

	if (RMI_I2C_PAGE(addr) != rmi_i2c->page) {

		retval = rmi_set_page(rmi_i2c, RMI_I2C_PAGE(addr));

		if (retval)

			goto exit;

	}

	retval = i2c_master_send(client, rmi_i2c->tx_buf, tx_size);

	if (retval == tx_size)

		retval = 0;

	else if (retval >= 0)

		retval = -EIO;

exit:

	rmi_dbg(RMI_DEBUG_XPORT, &client->dev,

		"write %zd bytes at %#06x: %d (%*ph)\n",

		len, addr, retval, (int)len, buf);

	mutex_unlock(&rmi_i2c->page_mutex);

	return retval;

}

static int rmi_i2c_read_block(struct rmi_transport_dev *xport, u16 addr,

			      void *buf, size_t len)

{

	struct rmi_i2c_xport *rmi_i2c =

		container_of(xport, struct rmi_i2c_xport, xport);

	struct i2c_client *client = rmi_i2c->client;

	u8 addr_offset = addr & 0xff;

	int retval;

	struct i2c_msg msgs[] = {

		{

			.addr	= client->addr,

			.len	= sizeof(addr_offset),

			.buf	= &addr_offset,

		},

		{

			.addr	= client->addr,

			.flags	= I2C_M_RD,

			.len	= len,

			.buf	= buf,

		},

	};

	mutex_lock(&rmi_i2c->page_mutex);

	if (RMI_I2C_PAGE(addr) != rmi_i2c->page) {

		retval = rmi_set_page(rmi_i2c, RMI_I2C_PAGE(addr));

		if (retval)

			goto exit;

	}

	retval = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));

	if (retval == ARRAY_SIZE(msgs))

		retval = 0; /* success */

	else if (retval >= 0)

		retval = -EIO;

exit:

	rmi_dbg(RMI_DEBUG_XPORT, &client->dev,

		"read %zd bytes at %#06x: %d (%*ph)\n",

		len, addr, retval, (int)len, buf);

	mutex_unlock(&rmi_i2c->page_mutex);

	return retval;

}

static const struct rmi_transport_ops rmi_i2c_ops = {

	.write_block	= rmi_i2c_write_block,

	.read_block	= rmi_i2c_read_block,

};

static irqreturn_t rmi_i2c_irq(int irq, void *dev_id)

{

	struct rmi_i2c_xport *rmi_i2c = dev_id;

	struct rmi_device *rmi_dev = rmi_i2c->xport.rmi_dev;

	int ret;

	ret = rmi_process_interrupt_requests(rmi_dev);

	if (ret)

		rmi_dbg(RMI_DEBUG_XPORT, &rmi_dev->dev,

			"Failed to process interrupt request: %d\n", ret);

	return IRQ_HANDLED;

}

static int rmi_i2c_init_irq(struct i2c_client *client)

{

	struct rmi_i2c_xport *rmi_i2c = i2c_get_clientdata(client);

	int irq_flags = irqd_get_trigger_type(irq_get_irq_data(rmi_i2c->irq));

	int ret;

	if (!irq_flags)

		irq_flags = IRQF_TRIGGER_LOW;

	ret = devm_request_threaded_irq(&client->dev, rmi_i2c->irq, NULL,

			rmi_i2c_irq, irq_flags | IRQF_ONESHOT, client->name,

			rmi_i2c);

	if (ret < 0) {

		dev_warn(&client->dev, "Failed to register interrupt %d\n",

			rmi_i2c->irq);

		return ret;

	}

	return 0;

}

static int rmi_i2c_probe(struct i2c_client *client,

			 const struct i2c_device_id *id)

{

	struct rmi_device_platform_data *pdata;

	struct rmi_device_platform_data *client_pdata =

					dev_get_platdata(&client->dev);

	struct rmi_i2c_xport *rmi_i2c;

	int retval;

	rmi_i2c = devm_kzalloc(&client->dev, sizeof(struct rmi_i2c_xport),

				GFP_KERNEL);

	if (!rmi_i2c)

		return -ENOMEM;

	pdata = &rmi_i2c->xport.pdata;

	if (client_pdata)

		*pdata = *client_pdata;

	if (client->irq > 0)

		rmi_i2c->irq = client->irq;

	rmi_dbg(RMI_DEBUG_XPORT, &client->dev, "Probing %s.\n",

			dev_name(&client->dev));

	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {

		dev_err(&client->dev,

			"adapter does not support required functionality.\n");

		return -ENODEV;

	}

	rmi_i2c->client = client;

	mutex_init(&rmi_i2c->page_mutex);

	rmi_i2c->xport.dev = &client->dev;

	rmi_i2c->xport.proto_name = "i2c";

	rmi_i2c->xport.ops = &rmi_i2c_ops;

	i2c_set_clientdata(client, rmi_i2c);

	/*

	 * Setting the page to zero will (a) make sure the PSR is in a

	 * known state, and (b) make sure we can talk to the device.

	 */

	retval = rmi_set_page(rmi_i2c, 0);

	if (retval) {

		dev_err(&client->dev, "Failed to set page select to 0.\n");

		return retval;

	}

	retval = rmi_register_transport_device(&rmi_i2c->xport);

	if (retval) {

		dev_err(&client->dev, "Failed to register transport driver at 0x%.2X.\n",

			client->addr);

		return retval;

	}

	retval = rmi_i2c_init_irq(client);

	if (retval < 0)

		return retval;

	dev_info(&client->dev, "registered rmi i2c driver at %#04x.\n",

			client->addr);

	return 0;

}

static int rmi_i2c_remove(struct i2c_client *client)

{

	struct rmi_i2c_xport *rmi_i2c = i2c_get_clientdata(client);

	rmi_unregister_transport_device(&rmi_i2c->xport);

	return 0;

}

#ifdef CONFIG_PM_SLEEP

static int rmi_i2c_suspend(struct device *dev)

{

	struct i2c_client *client = to_i2c_client(dev);

	struct rmi_i2c_xport *rmi_i2c = i2c_get_clientdata(client);

	int ret;

	ret = rmi_driver_suspend(rmi_i2c->xport.rmi_dev);

	if (ret)

		dev_warn(dev, "Failed to resume device: %d\n", ret);

	disable_irq(rmi_i2c->irq);

	if (device_may_wakeup(&client->dev)) {

		ret = enable_irq_wake(rmi_i2c->irq);

		if (!ret)

			dev_warn(dev, "Failed to enable irq for wake: %d\n",

				ret);

	}

	return ret;

}

static int rmi_i2c_resume(struct device *dev)

{

	struct i2c_client *client = to_i2c_client(dev);

	struct rmi_i2c_xport *rmi_i2c = i2c_get_clientdata(client);

	int ret;

	enable_irq(rmi_i2c->irq);

	if (device_may_wakeup(&client->dev)) {

		ret = disable_irq_wake(rmi_i2c->irq);

		if (!ret)

			dev_warn(dev, "Failed to disable irq for wake: %d\n",

				ret);

	}

	ret = rmi_driver_resume(rmi_i2c->xport.rmi_dev);

	if (ret)

		dev_warn(dev, "Failed to resume device: %d\n", ret);

	return ret;

}

#endif

#ifdef CONFIG_PM

static int rmi_i2c_runtime_suspend(struct device *dev)

{

	struct i2c_client *client = to_i2c_client(dev);

	struct rmi_i2c_xport *rmi_i2c = i2c_get_clientdata(client);

	int ret;

	ret = rmi_driver_suspend(rmi_i2c->xport.rmi_dev);

	if (ret)

		dev_warn(dev, "Failed to resume device: %d\n", ret);

	disable_irq(rmi_i2c->irq);

	return 0;

}

static int rmi_i2c_runtime_resume(struct device *dev)

{

	struct i2c_client *client = to_i2c_client(dev);

	struct rmi_i2c_xport *rmi_i2c = i2c_get_clientdata(client);

	int ret;

	enable_irq(rmi_i2c->irq);

	ret = rmi_driver_resume(rmi_i2c->xport.rmi_dev);

	if (ret)

		dev_warn(dev, "Failed to resume device: %d\n", ret);

	return 0;

}

#endif

static const struct dev_pm_ops rmi_i2c_pm = {

	SET_SYSTEM_SLEEP_PM_OPS(rmi_i2c_suspend, rmi_i2c_resume)

	SET_RUNTIME_PM_OPS(rmi_i2c_runtime_suspend, rmi_i2c_runtime_resume,

			   NULL)

};

static const struct i2c_device_id rmi_id[] = {

	{ "rmi4_i2c", 0 },

	{ }

};

MODULE_DEVICE_TABLE(i2c, rmi_id);

static struct i2c_driver rmi_i2c_driver = {

	.driver = {

		.name	= "rmi4_i2c",

		.pm	= &rmi_i2c_pm,

	},

	.id_table	= rmi_id,

	.probe		= rmi_i2c_probe,

	.remove		= rmi_i2c_remove,

};

module_i2c_driver(rmi_i2c_driver);

MODULE_AUTHOR("Christopher Heiny <cheiny@synaptics.com>");

MODULE_AUTHOR("Andrew Duggan <aduggan@synaptics.com>");

MODULE_DESCRIPTION("RMI I2C driver");

MODULE_LICENSE("GPL");

MODULE_VERSION(RMI_DRIVER_VERSION);