- 根目录:
- drivers
- hid
- i2c-hid
- i2c-hid.c
/*
* HID over I2C protocol implementation
*
* Copyright (c) 2012 Benjamin Tissoires <benjamin.tissoires@gmail.com>
* Copyright (c) 2012 Ecole Nationale de l'Aviation Civile, France
* Copyright (c) 2012 Red Hat, Inc
*
* This code is partly based on "USB HID support for Linux":
*
* Copyright (c) 1999 Andreas Gal
* Copyright (c) 2000-2005 Vojtech Pavlik <vojtech@suse.cz>
* Copyright (c) 2005 Michael Haboustak <mike-@cinci.rr.com> for Concept2, Inc
* Copyright (c) 2007-2008 Oliver Neukum
* Copyright (c) 2006-2010 Jiri Kosina
*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file COPYING in the main directory of this archive for
* more details.
*/
#include <linux/module.h>
#include <linux/i2c.h>
#include <linux/interrupt.h>
#include <linux/input.h>
#include <linux/delay.h>
#include <linux/slab.h>
#include <linux/pm.h>
#include <linux/pm_runtime.h>
#include <linux/device.h>
#include <linux/wait.h>
#include <linux/err.h>
#include <linux/string.h>
#include <linux/list.h>
#include <linux/jiffies.h>
#include <linux/kernel.h>
#include <linux/hid.h>
#include <linux/mutex.h>
#include <linux/acpi.h>
#include <linux/of.h>
#include <linux/gpio/consumer.h>
#include <linux/i2c/i2c-hid.h>
/* flags */
#define I2C_HID_STARTED (1 << 0)
#define I2C_HID_RESET_PENDING (1 << 1)
#define I2C_HID_READ_PENDING (1 << 2)
#define I2C_HID_PWR_ON 0x00
#define I2C_HID_PWR_SLEEP 0x01
/* debug option */
static bool debug;
module_param(debug, bool, 0444);
MODULE_PARM_DESC(debug, "print a lot of debug information");
#define i2c_hid_dbg(ihid, fmt, arg...) \
do { \
if (debug) \
dev_printk(KERN_DEBUG, &(ihid)->client->dev, fmt, ##arg); \
} while (0)
struct i2c_hid_desc {
__le16 wHIDDescLength;
__le16 bcdVersion;
__le16 wReportDescLength;
__le16 wReportDescRegister;
__le16 wInputRegister;
__le16 wMaxInputLength;
__le16 wOutputRegister;
__le16 wMaxOutputLength;
__le16 wCommandRegister;
__le16 wDataRegister;
__le16 wVendorID;
__le16 wProductID;
__le16 wVersionID;
__le32 reserved;
} __packed;
struct i2c_hid_cmd {
unsigned int registerIndex;
__u8 opcode;
unsigned int length;
bool wait;
};
union command {
u8 data[0];
struct cmd {
__le16 reg;
__u8 reportTypeID;
__u8 opcode;
} __packed c;
};
#define I2C_HID_CMD(opcode_) \
.opcode = opcode_, .length = 4, \
.registerIndex = offsetof(struct i2c_hid_desc, wCommandRegister)
/* fetch HID descriptor */
static const struct i2c_hid_cmd hid_descr_cmd = { .length = 2 };
/* fetch report descriptors */
static const struct i2c_hid_cmd hid_report_descr_cmd = {
.registerIndex = offsetof(struct i2c_hid_desc,
wReportDescRegister),
.opcode = 0x00,
.length = 2 };
/* commands */
static const struct i2c_hid_cmd hid_reset_cmd = { I2C_HID_CMD(0x01),
.wait = true };
static const struct i2c_hid_cmd hid_get_report_cmd = { I2C_HID_CMD(0x02) };
static const struct i2c_hid_cmd hid_set_report_cmd = { I2C_HID_CMD(0x03) };
static const struct i2c_hid_cmd hid_set_power_cmd = { I2C_HID_CMD(0x08) };
static const struct i2c_hid_cmd hid_no_cmd = { .length = 0 };
/*
* These definitions are not used here, but are defined by the spec.
* Keeping them here for documentation purposes.
*
* static const struct i2c_hid_cmd hid_get_idle_cmd = { I2C_HID_CMD(0x04) };
* static const struct i2c_hid_cmd hid_set_idle_cmd = { I2C_HID_CMD(0x05) };
* static const struct i2c_hid_cmd hid_get_protocol_cmd = { I2C_HID_CMD(0x06) };
* static const struct i2c_hid_cmd hid_set_protocol_cmd = { I2C_HID_CMD(0x07) };
*/
static DEFINE_MUTEX(i2c_hid_open_mut);
/* The main device structure */
struct i2c_hid {
struct i2c_client *client; /* i2c client */
struct hid_device *hid; /* pointer to corresponding HID dev */
union {
__u8 hdesc_buffer[sizeof(struct i2c_hid_desc)];
struct i2c_hid_desc hdesc; /* the HID Descriptor */
};
__le16 wHIDDescRegister; /* location of the i2c
* register of the HID
* descriptor. */
unsigned int bufsize; /* i2c buffer size */
char *inbuf; /* Input buffer */
char *rawbuf; /* Raw Input buffer */
char *cmdbuf; /* Command buffer */
char *argsbuf; /* Command arguments buffer */
unsigned long flags; /* device flags */
wait_queue_head_t wait; /* For waiting the interrupt */
struct gpio_desc *desc;
int irq;
struct i2c_hid_platform_data pdata;
};
static int __i2c_hid_command(struct i2c_client *client,
const struct i2c_hid_cmd *command, u8 reportID,
u8 reportType, u8 *args, int args_len,
unsigned char *buf_recv, int data_len)
{
struct i2c_hid *ihid = i2c_get_clientdata(client);
union command *cmd = (union command *)ihid->cmdbuf;
int ret;
struct i2c_msg msg[2];
int msg_num = 1;
int length = command->length;
bool wait = command->wait;
unsigned int registerIndex = command->registerIndex;
/* special case for hid_descr_cmd */
if (command == &hid_descr_cmd) {
cmd->c.reg = ihid->wHIDDescRegister;
} else {
cmd->data[0] = ihid->hdesc_buffer[registerIndex];
cmd->data[1] = ihid->hdesc_buffer[registerIndex + 1];
}
if (length > 2) {
cmd->c.opcode = command->opcode;
cmd->c.reportTypeID = reportID | reportType << 4;
}
memcpy(cmd->data + length, args, args_len);
length += args_len;
i2c_hid_dbg(ihid, "%s: cmd=%*ph\n", __func__, length, cmd->data);
msg[0].addr = client->addr;
msg[0].flags = client->flags & I2C_M_TEN;
msg[0].len = length;
msg[0].buf = cmd->data;
if (data_len > 0) {
msg[1].addr = client->addr;
msg[1].flags = client->flags & I2C_M_TEN;
msg[1].flags |= I2C_M_RD;
msg[1].len = data_len;
msg[1].buf = buf_recv;
msg_num = 2;
set_bit(I2C_HID_READ_PENDING, &ihid->flags);
}
if (wait)
set_bit(I2C_HID_RESET_PENDING, &ihid->flags);
ret = i2c_transfer(client->adapter, msg, msg_num);
if (data_len > 0)
clear_bit(I2C_HID_READ_PENDING, &ihid->flags);
if (ret != msg_num)
return ret < 0 ? ret : -EIO;
ret = 0;
if (wait) {
i2c_hid_dbg(ihid, "%s: waiting...\n", __func__);
if (!wait_event_timeout(ihid->wait,
!test_bit(I2C_HID_RESET_PENDING, &ihid->flags),
msecs_to_jiffies(5000)))
ret = -ENODATA;
i2c_hid_dbg(ihid, "%s: finished.\n", __func__);
}
return ret;
}
static int i2c_hid_command(struct i2c_client *client,
const struct i2c_hid_cmd *command,
unsigned char *buf_recv, int data_len)
{
return __i2c_hid_command(client, command, 0, 0, NULL, 0,
buf_recv, data_len);
}
static int i2c_hid_get_report(struct i2c_client *client, u8 reportType,
u8 reportID, unsigned char *buf_recv, int data_len)
{
struct i2c_hid *ihid = i2c_get_clientdata(client);
u8 args[3];
int ret;
int args_len = 0;
u16 readRegister = le16_to_cpu(ihid->hdesc.wDataRegister);
i2c_hid_dbg(ihid, "%s\n", __func__);
if (reportID >= 0x0F) {
args[args_len++] = reportID;
reportID = 0x0F;
}
args[args_len++] = readRegister & 0xFF;
args[args_len++] = readRegister >> 8;
ret = __i2c_hid_command(client, &hid_get_report_cmd, reportID,
reportType, args, args_len, buf_recv, data_len);
if (ret) {
dev_err(&client->dev,
"failed to retrieve report from device.\n");
return ret;
}
return 0;
}
/**
* i2c_hid_set_or_send_report: forward an incoming report to the device
* @client: the i2c_client of the device
* @reportType: 0x03 for HID_FEATURE_REPORT ; 0x02 for HID_OUTPUT_REPORT
* @reportID: the report ID
* @buf: the actual data to transfer, without the report ID
* @len: size of buf
* @use_data: true: use SET_REPORT HID command, false: send plain OUTPUT report
*/
static int i2c_hid_set_or_send_report(struct i2c_client *client, u8 reportType,
u8 reportID, unsigned char *buf, size_t data_len, bool use_data)
{
struct i2c_hid *ihid = i2c_get_clientdata(client);
u8 *args = ihid->argsbuf;
const struct i2c_hid_cmd *hidcmd;
int ret;
u16 dataRegister = le16_to_cpu(ihid->hdesc.wDataRegister);
u16 outputRegister = le16_to_cpu(ihid->hdesc.wOutputRegister);
u16 maxOutputLength = le16_to_cpu(ihid->hdesc.wMaxOutputLength);
/* hid_hw_* already checked that data_len < HID_MAX_BUFFER_SIZE */
u16 size = 2 /* size */ +
(reportID ? 1 : 0) /* reportID */ +
data_len /* buf */;
int args_len = (reportID >= 0x0F ? 1 : 0) /* optional third byte */ +
2 /* dataRegister */ +
size /* args */;
int index = 0;
i2c_hid_dbg(ihid, "%s\n", __func__);
if (!use_data && maxOutputLength == 0)
return -ENOSYS;
if (reportID >= 0x0F) {
args[index++] = reportID;
reportID = 0x0F;
}
/*
* use the data register for feature reports or if the device does not
* support the output register
*/
if (use_data) {
args[index++] = dataRegister & 0xFF;
args[index++] = dataRegister >> 8;
hidcmd = &hid_set_report_cmd;
} else {
args[index++] = outputRegister & 0xFF;
args[index++] = outputRegister >> 8;
hidcmd = &hid_no_cmd;
}
args[index++] = size & 0xFF;
args[index++] = size >> 8;
if (reportID)
args[index++] = reportID;
memcpy(&args[index], buf, data_len);
ret = __i2c_hid_command(client, hidcmd, reportID,
reportType, args, args_len, NULL, 0);
if (ret) {
dev_err(&client->dev, "failed to set a report to device.\n");
return ret;
}
return data_len;
}
static int i2c_hid_set_power(struct i2c_client *client, int power_state)
{
struct i2c_hid *ihid = i2c_get_clientdata(client);
int ret;
i2c_hid_dbg(ihid, "%s\n", __func__);
ret = __i2c_hid_command(client, &hid_set_power_cmd, power_state,
0, NULL, 0, NULL, 0);
if (ret)
dev_err(&client->dev, "failed to change power setting.\n");
return ret;
}
static int i2c_hid_hwreset(struct i2c_client *client)
{
struct i2c_hid *ihid = i2c_get_clientdata(client);
int ret;
i2c_hid_dbg(ihid, "%s\n", __func__);
ret = i2c_hid_set_power(client, I2C_HID_PWR_ON);
if (ret)
return ret;
i2c_hid_dbg(ihid, "resetting...\n");
ret = i2c_hid_command(client, &hid_reset_cmd, NULL, 0);
if (ret) {
dev_err(&client->dev, "failed to reset device.\n");
i2c_hid_set_power(client, I2C_HID_PWR_SLEEP);
return ret;
}
return 0;
}
static void i2c_hid_get_input(struct i2c_hid *ihid)
{
int ret, ret_size;
int size = le16_to_cpu(ihid->hdesc.wMaxInputLength);
if (size > ihid->bufsize)
size = ihid->bufsize;
ret = i2c_master_recv(ihid->client, ihid->inbuf, size);
if (ret != size) {
if (ret < 0)
return;
dev_err(&ihid->client->dev, "%s: got %d data instead of %d\n",
__func__, ret, size);
return;
}
ret_size = ihid->inbuf[0] | ihid->inbuf[1] << 8;
if (!ret_size) {
/* host or device initiated RESET completed */
if (test_and_clear_bit(I2C_HID_RESET_PENDING, &ihid->flags))
wake_up(&ihid->wait);
return;
}
if (ret_size > size) {
dev_err(&ihid->client->dev, "%s: incomplete report (%d/%d)\n",
__func__, size, ret_size);
return;
}
i2c_hid_dbg(ihid, "input: %*ph\n", ret_size, ihid->inbuf);
if (test_bit(I2C_HID_STARTED, &ihid->flags))
hid_input_report(ihid->hid, HID_INPUT_REPORT, ihid->inbuf + 2,
ret_size - 2, 1);
return;
}
static irqreturn_t i2c_hid_irq(int irq, void *dev_id)
{
struct i2c_hid *ihid = dev_id;
if (test_bit(I2C_HID_READ_PENDING, &ihid->flags))
return IRQ_HANDLED;
i2c_hid_get_input(ihid);
return IRQ_HANDLED;
}
static int i2c_hid_get_report_length(struct hid_report *report)
{
return ((report->size - 1) >> 3) + 1 +
report->device->report_enum[report->type].numbered + 2;
}
static void i2c_hid_init_report(struct hid_report *report, u8 *buffer,
size_t bufsize)
{
struct hid_device *hid = report->device;
struct i2c_client *client = hid->driver_data;
struct i2c_hid *ihid = i2c_get_clientdata(client);
unsigned int size, ret_size;
size = i2c_hid_get_report_length(report);
if (i2c_hid_get_report(client,
report->type == HID_FEATURE_REPORT ? 0x03 : 0x01,
report->id, buffer, size))
return;
i2c_hid_dbg(ihid, "report (len=%d): %*ph\n", size, size, buffer);
ret_size = buffer[0] | (buffer[1] << 8);
if (ret_size != size) {
dev_err(&client->dev, "error in %s size:%d / ret_size:%d\n",
__func__, size, ret_size);
return;
}
/* hid->driver_lock is held as we are in probe function,
* we just need to setup the input fields, so using
* hid_report_raw_event is safe. */
hid_report_raw_event(hid, report->type, buffer + 2, size - 2, 1);
}
/*
* Initialize all reports
*/
static void i2c_hid_init_reports(struct hid_device *hid)
{
struct hid_report *report;
struct i2c_client *client = hid->driver_data;
struct i2c_hid *ihid = i2c_get_clientdata(client);
u8 *inbuf = kzalloc(ihid->bufsize, GFP_KERNEL);
if (!inbuf) {
dev_err(&client->dev, "can not retrieve initial reports\n");
return;
}
/*
* The device must be powered on while we fetch initial reports
* from it.
*/
pm_runtime_get_sync(&client->dev);
list_for_each_entry(report,
&hid->report_enum[HID_FEATURE_REPORT].report_list, list)
i2c_hid_init_report(report, inbuf, ihid->bufsize);
pm_runtime_put(&client->dev);
kfree(inbuf);
}
/*
* Traverse the supplied list of reports and find the longest
*/
static void i2c_hid_find_max_report(struct hid_device *hid, unsigned int type,
unsigned int *max)
{
struct hid_report *report;
unsigned int size;
/* We should not rely on wMaxInputLength, as some devices may set it to
* a wrong length. */
list_for_each_entry(report, &hid->report_enum[type].report_list, list) {
size = i2c_hid_get_report_length(report);
if (*max < size)
*max = size;
}
}
static void i2c_hid_free_buffers(struct i2c_hid *ihid)
{
kfree(ihid->inbuf);
kfree(ihid->rawbuf);
kfree(ihid->argsbuf);
kfree(ihid->cmdbuf);
ihid->inbuf = NULL;
ihid->rawbuf = NULL;
ihid->cmdbuf = NULL;
ihid->argsbuf = NULL;
ihid->bufsize = 0;
}
static int i2c_hid_alloc_buffers(struct i2c_hid *ihid, size_t report_size)
{
/* the worst case is computed from the set_report command with a
* reportID > 15 and the maximum report length */
int args_len = sizeof(__u8) + /* optional ReportID byte */
sizeof(__u16) + /* data register */
sizeof(__u16) + /* size of the report */
report_size; /* report */
ihid->inbuf = kzalloc(report_size, GFP_KERNEL);
ihid->rawbuf = kzalloc(report_size, GFP_KERNEL);
ihid->argsbuf = kzalloc(args_len, GFP_KERNEL);
ihid->cmdbuf = kzalloc(sizeof(union command) + args_len, GFP_KERNEL);
if (!ihid->inbuf || !ihid->rawbuf || !ihid->argsbuf || !ihid->cmdbuf) {
i2c_hid_free_buffers(ihid);
return -ENOMEM;
}
ihid->bufsize = report_size;
return 0;
}
static int i2c_hid_get_raw_report(struct hid_device *hid,
unsigned char report_number, __u8 *buf, size_t count,
unsigned char report_type)
{
struct i2c_client *client = hid->driver_data;
struct i2c_hid *ihid = i2c_get_clientdata(client);
size_t ret_count, ask_count;
int ret;
if (report_type == HID_OUTPUT_REPORT)
return -EINVAL;
/* +2 bytes to include the size of the reply in the query buffer */
ask_count = min(count + 2, (size_t)ihid->bufsize);
ret = i2c_hid_get_report(client,
report_type == HID_FEATURE_REPORT ? 0x03 : 0x01,
report_number, ihid->rawbuf, ask_count);
if (ret < 0)
return ret;
ret_count = ihid->rawbuf[0] | (ihid->rawbuf[1] << 8);
if (ret_count <= 2)
return 0;
ret_count = min(ret_count, ask_count);
/* The query buffer contains the size, dropping it in the reply */
count = min(count, ret_count - 2);
memcpy(buf, ihid->rawbuf + 2, count);
return count;
}
static int i2c_hid_output_raw_report(struct hid_device *hid, __u8 *buf,
size_t count, unsigned char report_type, bool use_data)
{
struct i2c_client *client = hid->driver_data;
int report_id = buf[0];
int ret;
if (report_type == HID_INPUT_REPORT)
return -EINVAL;
if (report_id) {
buf++;
count--;
}
ret = i2c_hid_set_or_send_report(client,
report_type == HID_FEATURE_REPORT ? 0x03 : 0x02,
report_id, buf, count, use_data);
if (report_id && ret >= 0)
ret++; /* add report_id to the number of transfered bytes */
return ret;
}
static int i2c_hid_output_report(struct hid_device *hid, __u8 *buf,
size_t count)
{
return i2c_hid_output_raw_report(hid, buf, count, HID_OUTPUT_REPORT,
false);
}
static int i2c_hid_raw_request(struct hid_device *hid, unsigned char reportnum,
__u8 *buf, size_t len, unsigned char rtype,
int reqtype)
{
switch (reqtype) {
case HID_REQ_GET_REPORT:
return i2c_hid_get_raw_report(hid, reportnum, buf, len, rtype);
case HID_REQ_SET_REPORT:
if (buf[0] != reportnum)
return -EINVAL;
return i2c_hid_output_raw_report(hid, buf, len, rtype, true);
default:
return -EIO;
}
}
static int i2c_hid_parse(struct hid_device *hid)
{
struct i2c_client *client = hid->driver_data;
struct i2c_hid *ihid = i2c_get_clientdata(client);
struct i2c_hid_desc *hdesc = &ihid->hdesc;
unsigned int rsize;
char *rdesc;
int ret;
int tries = 3;
i2c_hid_dbg(ihid, "entering %s\n", __func__);
rsize = le16_to_cpu(hdesc->wReportDescLength);
if (!rsize || rsize > HID_MAX_DESCRIPTOR_SIZE) {
dbg_hid("weird size of report descriptor (%u)\n", rsize);
return -EINVAL;
}
do {
ret = i2c_hid_hwreset(client);
if (ret)
msleep(1000);
} while (tries-- > 0 && ret);
if (ret)
return ret;
rdesc = kzalloc(rsize, GFP_KERNEL);
if (!rdesc) {
dbg_hid("couldn't allocate rdesc memory\n");
return -ENOMEM;
}
i2c_hid_dbg(ihid, "asking HID report descriptor\n");
ret = i2c_hid_command(client, &hid_report_descr_cmd, rdesc, rsize);
if (ret) {
hid_err(hid, "reading report descriptor failed\n");
kfree(rdesc);
return -EIO;
}
i2c_hid_dbg(ihid, "Report Descriptor: %*ph\n", rsize, rdesc);
ret = hid_parse_report(hid, rdesc, rsize);
kfree(rdesc);
if (ret) {
dbg_hid("parsing report descriptor failed\n");
return ret;
}
return 0;
}
static int i2c_hid_start(struct hid_device *hid)
{
struct i2c_client *client = hid->driver_data;
struct i2c_hid *ihid = i2c_get_clientdata(client);
int ret;
unsigned int bufsize = HID_MIN_BUFFER_SIZE;
i2c_hid_find_max_report(hid, HID_INPUT_REPORT, &bufsize);
i2c_hid_find_max_report(hid, HID_OUTPUT_REPORT, &bufsize);
i2c_hid_find_max_report(hid, HID_FEATURE_REPORT, &bufsize);
if (bufsize > ihid->bufsize) {
i2c_hid_free_buffers(ihid);
ret = i2c_hid_alloc_buffers(ihid, bufsize);
if (ret)
return ret;
}
if (!(hid->quirks & HID_QUIRK_NO_INIT_REPORTS))
i2c_hid_init_reports(hid);
return 0;
}
static void i2c_hid_stop(struct hid_device *hid)
{
hid->claimed = 0;
}
static int i2c_hid_open(struct hid_device *hid)
{
struct i2c_client *client = hid->driver_data;
struct i2c_hid *ihid = i2c_get_clientdata(client);
int ret = 0;
mutex_lock(&i2c_hid_open_mut);
if (!hid->open++) {
ret = pm_runtime_get_sync(&client->dev);
if (ret < 0) {
hid->open--;
goto done;
}
set_bit(I2C_HID_STARTED, &ihid->flags);
}
done:
mutex_unlock(&i2c_hid_open_mut);
return ret < 0 ? ret : 0;
}
static void i2c_hid_close(struct hid_device *hid)
{
struct i2c_client *client = hid->driver_data;
struct i2c_hid *ihid = i2c_get_clientdata(client);
/* protecting hid->open to make sure we don't restart
* data acquistion due to a resumption we no longer
* care about
*/
mutex_lock(&i2c_hid_open_mut);
if (!--hid->open) {
clear_bit(I2C_HID_STARTED, &ihid->flags);
/* Save some power */
pm_runtime_put(&client->dev);
}
mutex_unlock(&i2c_hid_open_mut);
}
static int i2c_hid_power(struct hid_device *hid, int lvl)
{
struct i2c_client *client = hid->driver_data;
struct i2c_hid *ihid = i2c_get_clientdata(client);
i2c_hid_dbg(ihid, "%s lvl:%d\n", __func__, lvl);
switch (lvl) {
case PM_HINT_FULLON:
pm_runtime_get_sync(&client->dev);
break;
case PM_HINT_NORMAL:
pm_runtime_put(&client->dev);
break;
}
return 0;
}
static struct hid_ll_driver i2c_hid_ll_driver = {
.parse = i2c_hid_parse,
.start = i2c_hid_start,
.stop = i2c_hid_stop,
.open = i2c_hid_open,
.close = i2c_hid_close,
.power = i2c_hid_power,
.output_report = i2c_hid_output_report,
.raw_request = i2c_hid_raw_request,
};
static int i2c_hid_init_irq(struct i2c_client *client)
{
struct i2c_hid *ihid = i2c_get_clientdata(client);
int ret;
dev_dbg(&client->dev, "Requesting IRQ: %d\n", ihid->irq);
ret = request_threaded_irq(ihid->irq, NULL, i2c_hid_irq,
IRQF_TRIGGER_LOW | IRQF_ONESHOT,
client->name, ihid);
if (ret < 0) {
dev_warn(&client->dev,
"Could not register for %s interrupt, irq = %d,"
" ret = %d\n",
client->name, ihid->irq, ret);
return ret;
}
return 0;
}
static int i2c_hid_fetch_hid_descriptor(struct i2c_hid *ihid)
{
struct i2c_client *client = ihid->client;
struct i2c_hid_desc *hdesc = &ihid->hdesc;
unsigned int dsize;
int ret;
/* i2c hid fetch using a fixed descriptor size (30 bytes) */
i2c_hid_dbg(ihid, "Fetching the HID descriptor\n");
ret = i2c_hid_command(client, &hid_descr_cmd, ihid->hdesc_buffer,
sizeof(struct i2c_hid_desc));
if (ret) {
dev_err(&client->dev, "hid_descr_cmd failed\n");
return -ENODEV;
}
/* Validate the length of HID descriptor, the 4 first bytes:
* bytes 0-1 -> length
* bytes 2-3 -> bcdVersion (has to be 1.00) */
/* check bcdVersion == 1.0 */
if (le16_to_cpu(hdesc->bcdVersion) != 0x0100) {
dev_err(&client->dev,
"unexpected HID descriptor bcdVersion (0x%04hx)\n",
le16_to_cpu(hdesc->bcdVersion));
return -ENODEV;
}
/* Descriptor length should be 30 bytes as per the specification */
dsize = le16_to_cpu(hdesc->wHIDDescLength);
if (dsize != sizeof(struct i2c_hid_desc)) {
dev_err(&client->dev, "weird size of HID descriptor (%u)\n",
dsize);
return -ENODEV;
}
i2c_hid_dbg(ihid, "HID Descriptor: %*ph\n", dsize, ihid->hdesc_buffer);
return 0;
}
#ifdef CONFIG_ACPI
/* Default GPIO mapping */
static const struct acpi_gpio_params i2c_hid_irq_gpio = { 0, 0, true };
static const struct acpi_gpio_mapping i2c_hid_acpi_gpios[] = {
{ "gpios", &i2c_hid_irq_gpio, 1 },
{ },
};
static int i2c_hid_acpi_pdata(struct i2c_client *client,
struct i2c_hid_platform_data *pdata)
{
static u8 i2c_hid_guid[] = {
0xF7, 0xF6, 0xDF, 0x3C, 0x67, 0x42, 0x55, 0x45,
0xAD, 0x05, 0xB3, 0x0A, 0x3D, 0x89, 0x38, 0xDE,
};
union acpi_object *obj;
struct acpi_device *adev;
acpi_handle handle;
int ret;
handle = ACPI_HANDLE(&client->dev);
if (!handle || acpi_bus_get_device(handle, &adev))
return -ENODEV;
obj = acpi_evaluate_dsm_typed(handle, i2c_hid_guid, 1, 1, NULL,
ACPI_TYPE_INTEGER);
if (!obj) {
dev_err(&client->dev, "device _DSM execution failed\n");
return -ENODEV;
}
pdata->hid_descriptor_address = obj->integer.value;
ACPI_FREE(obj);
/* GPIOs are optional */
ret = acpi_dev_add_driver_gpios(adev, i2c_hid_acpi_gpios);
return ret < 0 && ret != -ENXIO ? ret : 0;
}
static const struct acpi_device_id i2c_hid_acpi_match[] = {
{"ACPI0C50", 0 },
{"PNP0C50", 0 },
{ },
};
MODULE_DEVICE_TABLE(acpi, i2c_hid_acpi_match);
#else
static inline int i2c_hid_acpi_pdata(struct i2c_client *client,
struct i2c_hid_platform_data *pdata)
{
return -ENODEV;
}
#endif
#ifdef CONFIG_OF
static int i2c_hid_of_probe(struct i2c_client *client,
struct i2c_hid_platform_data *pdata)
{
struct device *dev = &client->dev;
u32 val;
int ret;
ret = of_property_read_u32(dev->of_node, "hid-descr-addr", &val);
if (ret) {
dev_err(&client->dev, "HID register address not provided\n");
return -ENODEV;
}
if (val >> 16) {
dev_err(&client->dev, "Bad HID register address: 0x%08x\n",
val);
return -EINVAL;
}
pdata->hid_descriptor_address = val;
return 0;
}
static const struct of_device_id i2c_hid_of_match[] = {
{ .compatible = "hid-over-i2c" },
{},
};
MODULE_DEVICE_TABLE(of, i2c_hid_of_match);
#else
static inline int i2c_hid_of_probe(struct i2c_client *client,
struct i2c_hid_platform_data *pdata)
{
return -ENODEV;
}
#endif
static int i2c_hid_probe(struct i2c_client *client,
const struct i2c_device_id *dev_id)
{
int ret;
struct i2c_hid *ihid;
struct hid_device *hid;
__u16 hidRegister;
struct i2c_hid_platform_data *platform_data = client->dev.platform_data;
dbg_hid("HID probe called for i2c 0x%02x\n", client->addr);
ihid = kzalloc(sizeof(struct i2c_hid), GFP_KERNEL);
if (!ihid)
return -ENOMEM;
if (client->dev.of_node) {
ret = i2c_hid_of_probe(client, &ihid->pdata);
if (ret)
goto err;
} else if (!platform_data) {
ret = i2c_hid_acpi_pdata(client, &ihid->pdata);
if (ret) {
dev_err(&client->dev,
"HID register address not provided\n");
goto err;
}
} else {
ihid->pdata = *platform_data;
}
if (client->irq > 0) {
ihid->irq = client->irq;
} else if (ACPI_COMPANION(&client->dev)) {
ihid->desc = gpiod_get(&client->dev, NULL, GPIOD_IN);
if (IS_ERR(ihid->desc)) {
dev_err(&client->dev, "Failed to get GPIO interrupt\n");
return PTR_ERR(ihid->desc);
}
ihid->irq = gpiod_to_irq(ihid->desc);
if (ihid->irq < 0) {
gpiod_put(ihid->desc);
dev_err(&client->dev, "Failed to convert GPIO to IRQ\n");
return ihid->irq;
}
}
i2c_set_clientdata(client, ihid);
ihid->client = client;
hidRegister = ihid->pdata.hid_descriptor_address;
ihid->wHIDDescRegister = cpu_to_le16(hidRegister);
init_waitqueue_head(&ihid->wait);
/* we need to allocate the command buffer without knowing the maximum
* size of the reports. Let's use HID_MIN_BUFFER_SIZE, then we do the
* real computation later. */
ret = i2c_hid_alloc_buffers(ihid, HID_MIN_BUFFER_SIZE);
if (ret < 0)
goto err;
pm_runtime_get_noresume(&client->dev);
pm_runtime_set_active(&client->dev);
pm_runtime_enable(&client->dev);
ret = i2c_hid_fetch_hid_descriptor(ihid);
if (ret < 0)
goto err_pm;
ret = i2c_hid_init_irq(client);
if (ret < 0)
goto err_pm;
hid = hid_allocate_device();
if (IS_ERR(hid)) {
ret = PTR_ERR(hid);
goto err_irq;
}
ihid->hid = hid;
hid->driver_data = client;
hid->ll_driver = &i2c_hid_ll_driver;
hid->dev.parent = &client->dev;
ACPI_COMPANION_SET(&hid->dev, ACPI_COMPANION(&client->dev));
hid->bus = BUS_I2C;
hid->version = le16_to_cpu(ihid->hdesc.bcdVersion);
hid->vendor = le16_to_cpu(ihid->hdesc.wVendorID);
hid->product = le16_to_cpu(ihid->hdesc.wProductID);
snprintf(hid->name, sizeof(hid->name), "%s %04hX:%04hX",
client->name, hid->vendor, hid->product);
ret = hid_add_device(hid);
if (ret) {
if (ret != -ENODEV)
hid_err(client, "can't add hid device: %d\n", ret);
goto err_mem_free;
}
pm_runtime_put(&client->dev);
return 0;
err_mem_free:
hid_destroy_device(hid);
err_irq:
free_irq(ihid->irq, ihid);
err_pm:
pm_runtime_put_noidle(&client->dev);
pm_runtime_disable(&client->dev);
err:
if (ihid->desc)
gpiod_put(ihid->desc);
i2c_hid_free_buffers(ihid);
kfree(ihid);
return ret;
}
static int i2c_hid_remove(struct i2c_client *client)
{
struct i2c_hid *ihid = i2c_get_clientdata(client);
struct hid_device *hid;
pm_runtime_get_sync(&client->dev);
pm_runtime_disable(&client->dev);
pm_runtime_set_suspended(&client->dev);
pm_runtime_put_noidle(&client->dev);
hid = ihid->hid;
hid_destroy_device(hid);
free_irq(ihid->irq, ihid);
if (ihid->bufsize)
i2c_hid_free_buffers(ihid);
if (ihid->desc)
gpiod_put(ihid->desc);
kfree(ihid);
acpi_dev_remove_driver_gpios(ACPI_COMPANION(&client->dev));
return 0;
}
#ifdef CONFIG_PM_SLEEP
static int i2c_hid_suspend(struct device *dev)
{
struct i2c_client *client = to_i2c_client(dev);
struct i2c_hid *ihid = i2c_get_clientdata(client);
struct hid_device *hid = ihid->hid;
int ret = 0;
disable_irq(ihid->irq);
if (device_may_wakeup(&client->dev))
enable_irq_wake(ihid->irq);
if (hid->driver && hid->driver->suspend)
ret = hid->driver->suspend(hid, PMSG_SUSPEND);
/* Save some power */
i2c_hid_set_power(client, I2C_HID_PWR_SLEEP);
return ret;
}
static int i2c_hid_resume(struct device *dev)
{
int ret;
struct i2c_client *client = to_i2c_client(dev);
struct i2c_hid *ihid = i2c_get_clientdata(client);
struct hid_device *hid = ihid->hid;
enable_irq(ihid->irq);
ret = i2c_hid_hwreset(client);
if (ret)
return ret;
if (device_may_wakeup(&client->dev))
disable_irq_wake(ihid->irq);
if (hid->driver && hid->driver->reset_resume) {
ret = hid->driver->reset_resume(hid);
return ret;
}
return 0;
}
#endif
#ifdef CONFIG_PM
static int i2c_hid_runtime_suspend(struct device *dev)
{
struct i2c_client *client = to_i2c_client(dev);
struct i2c_hid *ihid = i2c_get_clientdata(client);
i2c_hid_set_power(client, I2C_HID_PWR_SLEEP);
disable_irq(ihid->irq);
return 0;
}
static int i2c_hid_runtime_resume(struct device *dev)
{
struct i2c_client *client = to_i2c_client(dev);
struct i2c_hid *ihid = i2c_get_clientdata(client);
enable_irq(ihid->irq);
i2c_hid_set_power(client, I2C_HID_PWR_ON);
return 0;
}
#endif
static const struct dev_pm_ops i2c_hid_pm = {
SET_SYSTEM_SLEEP_PM_OPS(i2c_hid_suspend, i2c_hid_resume)
SET_RUNTIME_PM_OPS(i2c_hid_runtime_suspend, i2c_hid_runtime_resume,
NULL)
};
static const struct i2c_device_id i2c_hid_id_table[] = {
{ "hid", 0 },
{ },
};
MODULE_DEVICE_TABLE(i2c, i2c_hid_id_table);
static struct i2c_driver i2c_hid_driver = {
.driver = {
.name = "i2c_hid",
.owner = THIS_MODULE,
.pm = &i2c_hid_pm,
.acpi_match_table = ACPI_PTR(i2c_hid_acpi_match),
.of_match_table = of_match_ptr(i2c_hid_of_match),
},
.probe = i2c_hid_probe,
.remove = i2c_hid_remove,
.id_table = i2c_hid_id_table,
};
module_i2c_driver(i2c_hid_driver);
MODULE_DESCRIPTION("HID over I2C core driver");
MODULE_AUTHOR("Benjamin Tissoires <benjamin.tissoires@gmail.com>");
MODULE_LICENSE("GPL");