Input: synaptics-rmi4 - add SMBus support

Code obtained from https://raw.githubusercontent.com/mightybigcar/synaptics-rmi4/jf/drivers/input/rmi4/rmi_smbus.c
and updated to match upstream. And fixed to make it work.

Signed-off-by: Benjamin Tissoires <[e-mail]>
Signed-off-by: Andrew Duggan <[e-mail]>
Signed-off-by: Dmitry Torokhov <[e-mail]>

drivers/input/rmi4/Kconfig

···
 
 	  If unsure, say N.
 
+config RMI4_SMB
+	tristate "RMI4 SMB Support"
+	depends on RMI4_CORE && I2C
+	help
+	  Say Y here if you want to support RMI4 devices connected to an SMB
+	  bus.
+
+	  If unsure, say N.
+
+	  To compile this driver as a module, choose M here: the module will be
+	  called rmi_smbus.
+
 config RMI4_2D_SENSOR
 	bool
 	depends on RMI4_CORE

drivers/input/rmi4/Makefile

···
 # Transports
 obj-$(CONFIG_RMI4_I2C) += rmi_i2c.o
 obj-$(CONFIG_RMI4_SPI) += rmi_spi.o
+obj-$(CONFIG_RMI4_SMB) += rmi_smbus.o

drivers/input/rmi4/rmi_bus.h

···
 bool rmi_is_physical_device(struct device *dev);
 
 /**
+ * rmi_reset - reset a RMI4 device
+ * @d: Pointer to an RMI device
+ *
+ * Calls for a reset of each function implemented by a specific device.
+ * Returns 0 on success or a negative error code.
+ */
+static inline int rmi_reset(struct rmi_device *d)
+{
+	return d->driver->reset_handler(d);
+}
+
+/**
  * rmi_read - read a single byte
  * @d: Pointer to an RMI device
  * @addr: The address to read from

drivers/input/rmi4/rmi_smbus.c

···
+/*
+ * Copyright (c) 2015 - 2016 Red Hat, Inc
+ * Copyright (c) 2011, 2012 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/kernel.h>
+#include <linux/delay.h>
+#include <linux/i2c.h>
+#include <linux/interrupt.h>
+#include <linux/kconfig.h>
+#include <linux/lockdep.h>
+#include <linux/module.h>
+#include <linux/pm.h>
+#include <linux/rmi.h>
+#include <linux/slab.h>
+#include "rmi_driver.h"
+
+#define SMB_PROTOCOL_VERSION_ADDRESS	0xfd
+#define SMB_MAX_COUNT			32
+#define RMI_SMB2_MAP_SIZE		8 /* 8 entry of 4 bytes each */
+#define RMI_SMB2_MAP_FLAGS_WE		0x01
+
+struct mapping_table_entry {
+	__le16 rmiaddr;
+	u8 readcount;
+	u8 flags;
+};
+
+struct rmi_smb_xport {
+	struct rmi_transport_dev xport;
+	struct i2c_client *client;
+
+	struct mutex page_mutex;
+	int page;
+	u8 table_index;
+	struct mutex mappingtable_mutex;
+	struct mapping_table_entry mapping_table[RMI_SMB2_MAP_SIZE];
+};
+
+static int rmi_smb_get_version(struct rmi_smb_xport *rmi_smb)
+{
+	struct i2c_client *client = rmi_smb->client;
+	int retval;
+
+	/* Check if for SMBus new version device by reading version byte. */
+	retval = i2c_smbus_read_byte_data(client, SMB_PROTOCOL_VERSION_ADDRESS);
+	if (retval < 0) {
+		dev_err(&client->dev, "failed to get SMBus version number!\n");
+		return retval;
+	}
+	return retval + 1;
+}
+
+/* SMB block write - wrapper over ic2_smb_write_block */
+static int smb_block_write(struct rmi_transport_dev *xport,
+			      u8 commandcode, const void *buf, size_t len)
+{
+	struct rmi_smb_xport *rmi_smb =
+		container_of(xport, struct rmi_smb_xport, xport);
+	struct i2c_client *client = rmi_smb->client;
+	int retval;
+
+	retval = i2c_smbus_write_block_data(client, commandcode, len, buf);
+
+	rmi_dbg(RMI_DEBUG_XPORT, &client->dev,
+		"wrote %zd bytes at %#04x: %d (%*ph)\n",
+		len, commandcode, retval, (int)len, buf);
+
+	return retval;
+}
+
+/*
+ * The function to get command code for smbus operations and keeps
+ * records to the driver mapping table
+ */
+static int rmi_smb_get_command_code(struct rmi_transport_dev *xport,
+		u16 rmiaddr, int bytecount, bool isread, u8 *commandcode)
+{
+	struct rmi_smb_xport *rmi_smb =
+		container_of(xport, struct rmi_smb_xport, xport);
+	int i;
+	int retval;
+	struct mapping_table_entry mapping_data[1];
+
+	mutex_lock(&rmi_smb->mappingtable_mutex);
+	for (i = 0; i < RMI_SMB2_MAP_SIZE; i++) {
+		if (rmi_smb->mapping_table[i].rmiaddr == rmiaddr) {
+			if (isread) {
+				if (rmi_smb->mapping_table[i].readcount
+							== bytecount) {
+					*commandcode = i;
+					retval = 0;
+					goto exit;
+				}
+			} else {
+				if (rmi_smb->mapping_table[i].flags &
+							RMI_SMB2_MAP_FLAGS_WE) {
+					*commandcode = i;
+					retval = 0;
+					goto exit;
+				}
+			}
+		}
+	}
+	i = rmi_smb->table_index;
+	rmi_smb->table_index = (i + 1) % RMI_SMB2_MAP_SIZE;
+
+	/* constructs mapping table data entry. 4 bytes each entry */
+	memset(mapping_data, 0, sizeof(mapping_data));
+
+	mapping_data[0].rmiaddr = cpu_to_le16(rmiaddr);
+	mapping_data[0].readcount = bytecount;
+	mapping_data[0].flags = !isread ? RMI_SMB2_MAP_FLAGS_WE : 0;
+
+	retval = smb_block_write(xport, i + 0x80, mapping_data,
+				 sizeof(mapping_data));
+
+	if (retval < 0) {
+		/*
+		 * if not written to device mapping table
+		 * clear the driver mapping table records
+		 */
+		rmi_smb->mapping_table[i].rmiaddr = 0x0000;
+		rmi_smb->mapping_table[i].readcount = 0;
+		rmi_smb->mapping_table[i].flags = 0;
+		goto exit;
+	}
+	/* save to the driver level mapping table */
+	rmi_smb->mapping_table[i].rmiaddr = rmiaddr;
+	rmi_smb->mapping_table[i].readcount = bytecount;
+	rmi_smb->mapping_table[i].flags = !isread ? RMI_SMB2_MAP_FLAGS_WE : 0;
+	*commandcode = i;
+
+exit:
+	mutex_unlock(&rmi_smb->mappingtable_mutex);
+
+	return retval;
+}
+
+static int rmi_smb_write_block(struct rmi_transport_dev *xport, u16 rmiaddr,
+				const void *databuff, size_t len)
+{
+	int retval = 0;
+	u8 commandcode;
+	struct rmi_smb_xport *rmi_smb =
+		container_of(xport, struct rmi_smb_xport, xport);
+	int cur_len = (int)len;
+
+	mutex_lock(&rmi_smb->page_mutex);
+
+	while (cur_len > 0) {
+		/*
+		 * break into 32 bytes chunks to write get command code
+		 */
+		int block_len = min_t(int, len, SMB_MAX_COUNT);
+
+		retval = rmi_smb_get_command_code(xport, rmiaddr, block_len,
+						  false, &commandcode);
+		if (retval < 0)
+			goto exit;
+
+		retval = smb_block_write(xport, commandcode,
+					 databuff, block_len);
+		if (retval < 0)
+			goto exit;
+
+		/* prepare to write next block of bytes */
+		cur_len -= SMB_MAX_COUNT;
+		databuff += SMB_MAX_COUNT;
+		rmiaddr += SMB_MAX_COUNT;
+	}
+exit:
+	mutex_unlock(&rmi_smb->page_mutex);
+	return retval;
+}
+
+/* SMB block read - wrapper over ic2_smb_read_block */
+static int smb_block_read(struct rmi_transport_dev *xport,
+			     u8 commandcode, void *buf, size_t len)
+{
+	struct rmi_smb_xport *rmi_smb =
+		container_of(xport, struct rmi_smb_xport, xport);
+	struct i2c_client *client = rmi_smb->client;
+	int retval;
+
+	retval = i2c_smbus_read_block_data(client, commandcode, buf);
+	if (retval < 0)
+		return retval;
+
+	return retval;
+}
+
+static int rmi_smb_read_block(struct rmi_transport_dev *xport, u16 rmiaddr,
+			      void *databuff, size_t len)
+{
+	struct rmi_smb_xport *rmi_smb =
+		container_of(xport, struct rmi_smb_xport, xport);
+	int retval;
+	u8 commandcode;
+	int cur_len = (int)len;
+
+	mutex_lock(&rmi_smb->page_mutex);
+	memset(databuff, 0, len);
+
+	while (cur_len > 0) {
+		/* break into 32 bytes chunks to write get command code */
+		int block_len =  min_t(int, cur_len, SMB_MAX_COUNT);
+
+		retval = rmi_smb_get_command_code(xport, rmiaddr, block_len,
+						  true, &commandcode);
+		if (retval < 0)
+			goto exit;
+
+		retval = smb_block_read(xport, commandcode,
+					databuff, block_len);
+		if (retval < 0)
+			goto exit;
+
+		/* prepare to read next block of bytes */
+		cur_len -= SMB_MAX_COUNT;
+		databuff += SMB_MAX_COUNT;
+		rmiaddr += SMB_MAX_COUNT;
+	}
+
+	retval = 0;
+
+exit:
+	mutex_unlock(&rmi_smb->page_mutex);
+	return retval;
+}
+
+static void rmi_smb_clear_state(struct rmi_smb_xport *rmi_smb)
+{
+	/* the mapping table has been flushed, discard the current one */
+	mutex_lock(&rmi_smb->mappingtable_mutex);
+	memset(rmi_smb->mapping_table, 0, sizeof(rmi_smb->mapping_table));
+	mutex_unlock(&rmi_smb->mappingtable_mutex);
+}
+
+static int rmi_smb_enable_smbus_mode(struct rmi_smb_xport *rmi_smb)
+{
+	int retval;
+
+	/* we need to get the smbus version to activate the touchpad */
+	retval = rmi_smb_get_version(rmi_smb);
+	if (retval < 0)
+		return retval;
+
+	return 0;
+}
+
+static int rmi_smb_reset(struct rmi_transport_dev *xport, u16 reset_addr)
+{
+	struct rmi_smb_xport *rmi_smb =
+		container_of(xport, struct rmi_smb_xport, xport);
+
+	rmi_smb_clear_state(rmi_smb);
+
+	/*
+	 * we do not call the actual reset command, it has to be handled in
+	 * PS/2 or there will be races between PS/2 and SMBus.
+	 * PS/2 should ensure that a psmouse_reset is called before
+	 * intializing the device and after it has been removed to be in a known
+	 * state.
+	 */
+	return rmi_smb_enable_smbus_mode(rmi_smb);
+}
+
+static const struct rmi_transport_ops rmi_smb_ops = {
+	.write_block	= rmi_smb_write_block,
+	.read_block	= rmi_smb_read_block,
+	.reset		= rmi_smb_reset,
+};
+
+static int rmi_smb_probe(struct i2c_client *client,
+			 const struct i2c_device_id *id)
+{
+	struct rmi_device_platform_data *pdata = dev_get_platdata(&client->dev);
+	struct rmi_smb_xport *rmi_smb;
+	int retval;
+	int smbus_version;
+
+	if (!i2c_check_functionality(client->adapter,
+				     I2C_FUNC_SMBUS_READ_BLOCK_DATA |
+				     I2C_FUNC_SMBUS_HOST_NOTIFY)) {
+		dev_err(&client->dev,
+			"adapter does not support required functionality.\n");
+		return -ENODEV;
+	}
+
+	if (client->irq <= 0) {
+		dev_err(&client->dev, "no IRQ provided, giving up.\n");
+		return client->irq ? client->irq : -ENODEV;
+	}
+
+	rmi_smb = devm_kzalloc(&client->dev, sizeof(struct rmi_smb_xport),
+				GFP_KERNEL);
+	if (!rmi_smb)
+		return -ENOMEM;
+
+	if (!pdata) {
+		dev_err(&client->dev, "no platform data, aborting\n");
+		return -ENOMEM;
+	}
+
+	rmi_dbg(RMI_DEBUG_XPORT, &client->dev, "Probing %s.\n",
+		dev_name(&client->dev));
+
+	rmi_smb->client = client;
+	mutex_init(&rmi_smb->page_mutex);
+	mutex_init(&rmi_smb->mappingtable_mutex);
+
+	rmi_smb->xport.dev = &client->dev;
+	rmi_smb->xport.pdata = *pdata;
+	rmi_smb->xport.pdata.irq = client->irq;
+	rmi_smb->xport.proto_name = "smb2";
+	rmi_smb->xport.ops = &rmi_smb_ops;
+
+	retval = rmi_smb_get_version(rmi_smb);
+	if (retval < 0)
+		return retval;
+
+	smbus_version = retval;
+	rmi_dbg(RMI_DEBUG_XPORT, &client->dev, "Smbus version is %d",
+		smbus_version);
+
+	if (smbus_version != 2) {
+		dev_err(&client->dev, "Unrecognized SMB version %d.\n",
+				smbus_version);
+		return -ENODEV;
+	}
+
+	i2c_set_clientdata(client, rmi_smb);
+
+	retval = rmi_register_transport_device(&rmi_smb->xport);
+	if (retval) {
+		dev_err(&client->dev, "Failed to register transport driver at 0x%.2X.\n",
+			client->addr);
+		i2c_set_clientdata(client, NULL);
+		return retval;
+	}
+
+	dev_info(&client->dev, "registered rmi smb driver at %#04x.\n",
+			client->addr);
+	return 0;
+
+}
+
+static int rmi_smb_remove(struct i2c_client *client)
+{
+	struct rmi_smb_xport *rmi_smb = i2c_get_clientdata(client);
+
+	rmi_unregister_transport_device(&rmi_smb->xport);
+
+	return 0;
+}
+
+static int __maybe_unused rmi_smb_suspend(struct device *dev)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct rmi_smb_xport *rmi_smb = i2c_get_clientdata(client);
+	int ret;
+
+	ret = rmi_driver_suspend(rmi_smb->xport.rmi_dev, true);
+	if (ret)
+		dev_warn(dev, "Failed to suspend device: %d\n", ret);
+
+	return ret;
+}
+
+static int __maybe_unused rmi_smb_runtime_suspend(struct device *dev)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct rmi_smb_xport *rmi_smb = i2c_get_clientdata(client);
+	int ret;
+
+	ret = rmi_driver_suspend(rmi_smb->xport.rmi_dev, false);
+	if (ret)
+		dev_warn(dev, "Failed to suspend device: %d\n", ret);
+
+	return ret;
+}
+
+static int __maybe_unused rmi_smb_resume(struct device *dev)
+{
+	struct i2c_client *client = container_of(dev, struct i2c_client, dev);
+	struct rmi_smb_xport *rmi_smb = i2c_get_clientdata(client);
+	struct rmi_device *rmi_dev = rmi_smb->xport.rmi_dev;
+	int ret;
+
+	rmi_smb_reset(&rmi_smb->xport, 0);
+
+	rmi_reset(rmi_dev);
+
+	ret = rmi_driver_resume(rmi_smb->xport.rmi_dev, true);
+	if (ret)
+		dev_warn(dev, "Failed to resume device: %d\n", ret);
+
+	return 0;
+}
+
+static int __maybe_unused rmi_smb_runtime_resume(struct device *dev)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct rmi_smb_xport *rmi_smb = i2c_get_clientdata(client);
+	int ret;
+
+	ret = rmi_driver_resume(rmi_smb->xport.rmi_dev, false);
+	if (ret)
+		dev_warn(dev, "Failed to resume device: %d\n", ret);
+
+	return 0;
+}
+
+static const struct dev_pm_ops rmi_smb_pm = {
+	SET_SYSTEM_SLEEP_PM_OPS(rmi_smb_suspend, rmi_smb_resume)
+	SET_RUNTIME_PM_OPS(rmi_smb_runtime_suspend, rmi_smb_runtime_resume,
+			   NULL)
+};
+
+static const struct i2c_device_id rmi_id[] = {
+	{ "rmi4_smbus", 0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, rmi_id);
+
+static struct i2c_driver rmi_smb_driver = {
+	.driver = {
+		.name	= "rmi4_smbus",
+		.pm	= &rmi_smb_pm,
+	},
+	.id_table	= rmi_id,
+	.probe		= rmi_smb_probe,
+	.remove		= rmi_smb_remove,
+};
+
+module_i2c_driver(rmi_smb_driver);
+
+MODULE_AUTHOR("Andrew Duggan <[e-mail]>");
+MODULE_AUTHOR("Benjamin Tissoires <[e-mail]>");
+MODULE_DESCRIPTION("RMI4 SMBus driver");
+MODULE_LICENSE("GPL");