rmi_smbus.c
// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (c) 2015 - 2016 Red Hat, Inc
* Copyright (c) 2011, 2012 Synaptics Incorporated
* Copyright (c) 2011 Unixphere
*/
#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);
struct mapping_table_entry new_map;
int i;
int retval = 0;
mutex_lock(&rmi_smb->mappingtable_mutex);
for (i = 0; i < RMI_SMB2_MAP_SIZE; i++) {
struct mapping_table_entry *entry = &rmi_smb->mapping_table[i];
if (le16_to_cpu(entry->rmiaddr) == rmiaddr) {
if (isread) {
if (entry->readcount == bytecount)
goto exit;
} else {
if (entry->flags & RMI_SMB2_MAP_FLAGS_WE) {
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(&new_map, 0, sizeof(new_map));
new_map.rmiaddr = cpu_to_le16(rmiaddr);
new_map.readcount = bytecount;
new_map.flags = !isread ? RMI_SMB2_MAP_FLAGS_WE : 0;
retval = smb_block_write(xport, i + 0x80, &new_map, sizeof(new_map));
if (retval < 0) {
/*
* if not written to device mapping table
* clear the driver mapping table records
*/
memset(&new_map, 0, sizeof(new_map));
}
/* save to the driver level mapping table */
rmi_smb->mapping_table[i] = new_map;
exit:
mutex_unlock(&rmi_smb->mappingtable_mutex);
if (retval < 0)
return retval;
*commandcode = i;
return 0;
}
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 smbus_version;
int error;
if (!pdata) {
dev_err(&client->dev, "no platform data, aborting\n");
return -ENOMEM;
}
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;
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 = "smb";
rmi_smb->xport.ops = &rmi_smb_ops;
smbus_version = rmi_smb_get_version(rmi_smb);
if (smbus_version < 0)
return smbus_version;
rmi_dbg(RMI_DEBUG_XPORT, &client->dev, "Smbus version is %d",
smbus_version);
if (smbus_version != 2 && smbus_version != 3) {
dev_err(&client->dev, "Unrecognized SMB version %d\n",
smbus_version);
return -ENODEV;
}
i2c_set_clientdata(client, rmi_smb);
dev_info(&client->dev, "registering SMbus-connected sensor\n");
error = rmi_register_transport_device(&rmi_smb->xport);
if (error) {
dev_err(&client->dev, "failed to register sensor: %d\n", error);
return error;
}
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 <aduggan@synaptics.com>");
MODULE_AUTHOR("Benjamin Tissoires <benjamin.tissoires@redhat.com>");
MODULE_DESCRIPTION("RMI4 SMBus driver");
MODULE_LICENSE("GPL");