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i2c-hid-core.c
1439 lines (1182 loc) · 36.9 KB
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i2c-hid-core.c
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/*
* 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/irq.h>
#include <linux/delay.h>
#include <linux/slab.h>
#include <linux/pm.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/kthread.h>
#include <linux/gpio/driver.h>
#include <linux/of.h>
#include <linux/regulator/consumer.h>
#include <linux/platform_data/i2c-hid.h>
#include "../hid-ids.h"
#include "i2c-hid.h"
/* quirks to control the device */
#define I2C_HID_QUIRK_SET_PWR_WAKEUP_DEV BIT(0)
#define I2C_HID_QUIRK_NO_IRQ_AFTER_RESET BIT(1)
#define I2C_HID_QUIRK_BOGUS_IRQ BIT(4)
#define I2C_HID_QUIRK_RESET_ON_RESUME BIT(5)
#define I2C_HID_QUIRK_BAD_INPUT_SIZE BIT(6)
/* flags */
#define I2C_HID_STARTED 0
#define I2C_HID_RESET_PENDING 1
#define I2C_HID_READ_PENDING 2
#define I2C_HID_PWR_ON 0x00
#define I2C_HID_PWR_SLEEP 0x01
/* polling mode */
#define I2C_HID_POLLING_DISABLED 0
#define I2C_HID_POLLING_GPIO_PIN 1
#define I2C_HID_POLLING_INTERVAL_ACTIVE_US 4000
#define I2C_HID_POLLING_INTERVAL_IDLE_MS 10
static u8 polling_mode;
module_param(polling_mode, byte, 0444);
MODULE_PARM_DESC(polling_mode, "How to poll (default=0) - 0 disabled; 1 based on GPIO pin's status");
static unsigned int polling_interval_active_us __read_mostly = I2C_HID_POLLING_INTERVAL_ACTIVE_US;
module_param(polling_interval_active_us, uint, 0644);
MODULE_PARM_DESC(polling_interval_active_us,
"Poll every {polling_interval_active_us} us when the touchpad is active (default=" __stringify(I2C_HID_POLLING_INTERVAL_ACTIVE_US) " us)");
static unsigned int polling_interval_idle_ms __read_mostly = I2C_HID_POLLING_INTERVAL_IDLE_MS;
module_param(polling_interval_idle_ms, uint, 0644);
MODULE_PARM_DESC(polling_interval_idle_ms,
"Poll every {polling_interval_idle_ms} ms when the touchpad is idle (default=" __stringify(I2C_HID_POLLING_INTERVAL_IDLE_MS) "ms)");
/* 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) };
*/
/* 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 */
u8 *inbuf; /* Input buffer */
u8 *rawbuf; /* Raw Input buffer */
u8 *cmdbuf; /* Command buffer */
u8 *argsbuf; /* Command arguments buffer */
unsigned long flags; /* device flags */
unsigned long quirks; /* Various quirks */
wait_queue_head_t wait; /* For waiting the interrupt */
struct i2c_hid_platform_data pdata;
struct task_struct *polling_thread;
unsigned long irq_trigger_type;
struct irq_desc *irq_desc;
bool irq_wake_enabled;
struct mutex reset_lock;
};
static const struct i2c_hid_quirks {
__u16 idVendor;
__u16 idProduct;
__u32 quirks;
} i2c_hid_quirks[] = {
{ USB_VENDOR_ID_WEIDA, HID_ANY_ID,
I2C_HID_QUIRK_SET_PWR_WAKEUP_DEV },
{ I2C_VENDOR_ID_HANTICK, I2C_PRODUCT_ID_HANTICK_5288,
I2C_HID_QUIRK_NO_IRQ_AFTER_RESET },
{ I2C_VENDOR_ID_RAYDIUM, I2C_PRODUCT_ID_RAYDIUM_3118,
I2C_HID_QUIRK_NO_IRQ_AFTER_RESET },
{ USB_VENDOR_ID_ELAN, HID_ANY_ID,
I2C_HID_QUIRK_BOGUS_IRQ },
{ USB_VENDOR_ID_ALPS_JP, HID_ANY_ID,
I2C_HID_QUIRK_RESET_ON_RESUME },
{ I2C_VENDOR_ID_SYNAPTICS, I2C_PRODUCT_ID_SYNAPTICS_SYNA2393,
I2C_HID_QUIRK_RESET_ON_RESUME },
{ USB_VENDOR_ID_ITE, I2C_DEVICE_ID_ITE_LENOVO_LEGION_Y720,
I2C_HID_QUIRK_BAD_INPUT_SIZE },
{ 0, 0 }
};
/*
* i2c_hid_lookup_quirk: return any quirks associated with a I2C HID device
* @idVendor: the 16-bit vendor ID
* @idProduct: the 16-bit product ID
*
* Returns: a u32 quirks value.
*/
static u32 i2c_hid_lookup_quirk(const u16 idVendor, const u16 idProduct)
{
u32 quirks = 0;
int n;
for (n = 0; i2c_hid_quirks[n].idVendor; n++)
if (i2c_hid_quirks[n].idVendor == idVendor &&
(i2c_hid_quirks[n].idProduct == (__u16)HID_ANY_ID ||
i2c_hid_quirks[n].idProduct == idProduct))
quirks = i2c_hid_quirks[n].quirks;
return quirks;
}
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 && (ihid->quirks & I2C_HID_QUIRK_NO_IRQ_AFTER_RESET)) {
msleep(100);
} else 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
* @data_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);
u16 size;
int args_len;
int index = 0;
i2c_hid_dbg(ihid, "%s\n", __func__);
if (data_len > ihid->bufsize)
return -EINVAL;
size = 2 /* size */ +
(reportID ? 1 : 0) /* reportID */ +
data_len /* buf */;
args_len = (reportID >= 0x0F ? 1 : 0) /* optional third byte */ +
2 /* dataRegister */ +
size /* args */;
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__);
/*
* Some devices require to send a command to wakeup before power on.
* The call will get a return value (EREMOTEIO) but device will be
* triggered and activated. After that, it goes like a normal device.
*/
if (power_state == I2C_HID_PWR_ON &&
ihid->quirks & I2C_HID_QUIRK_SET_PWR_WAKEUP_DEV) {
ret = i2c_hid_command(client, &hid_set_power_cmd, NULL, 0);
/* Device was already activated */
if (!ret)
goto set_pwr_exit;
}
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");
set_pwr_exit:
/*
* The HID over I2C specification states that if a DEVICE needs time
* after the PWR_ON request, it should utilise CLOCK stretching.
* However, it has been observered that the Windows driver provides a
* 1ms sleep between the PWR_ON and RESET requests.
* According to Goodix Windows even waits 60 ms after (other?)
* PWR_ON requests. Testing has confirmed that several devices
* will not work properly without a delay after a PWR_ON request.
*/
if (!ret && power_state == I2C_HID_PWR_ON)
msleep(60);
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__);
/*
* This prevents sending feature reports while the device is
* being reset. Otherwise we may lose the reset complete
* interrupt.
*/
mutex_lock(&ihid->reset_lock);
ret = i2c_hid_set_power(client, I2C_HID_PWR_ON);
if (ret)
goto out_unlock;
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);
goto out_unlock;
}
/* At least some SIS devices need this after reset */
ret = i2c_hid_set_power(client, I2C_HID_PWR_ON);
out_unlock:
mutex_unlock(&ihid->reset_lock);
return ret;
}
static void i2c_hid_get_input(struct i2c_hid *ihid)
{
int ret;
u32 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 (ihid->quirks & I2C_HID_QUIRK_BOGUS_IRQ && ret_size == 0xffff) {
dev_warn_once(&ihid->client->dev, "%s: IRQ triggered but "
"there's no data\n", __func__);
return;
}
if ((ret_size > size) || (ret_size < 2)) {
if (ihid->quirks & I2C_HID_QUIRK_BAD_INPUT_SIZE) {
ihid->inbuf[0] = size & 0xff;
ihid->inbuf[1] = size >> 8;
ret_size = size;
} else {
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;
}
/*
* 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) + /* ReportID */
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;
struct i2c_hid *ihid = i2c_get_clientdata(client);
int report_id = buf[0];
int ret;
if (report_type == HID_INPUT_REPORT)
return -EINVAL;
mutex_lock(&ihid->reset_lock);
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 */
mutex_unlock(&ihid->reset_lock);
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;
char *use_override;
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;
use_override = i2c_hid_get_dmi_hid_report_desc_override(client->name,
&rsize);
if (use_override) {
rdesc = use_override;
i2c_hid_dbg(ihid, "Using a HID report descriptor override\n");
} else {
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);
if (!use_override)
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) {
disable_irq(client->irq);
i2c_hid_free_buffers(ihid);
ret = i2c_hid_alloc_buffers(ihid, bufsize);
if (polling_mode == I2C_HID_POLLING_DISABLED)
enable_irq(client->irq);
if (ret)
return ret;
}
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);
set_bit(I2C_HID_STARTED, &ihid->flags);
return 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);
clear_bit(I2C_HID_STARTED, &ihid->flags);
}
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,
.output_report = i2c_hid_output_report,
.raw_request = i2c_hid_raw_request,
};
EXPORT_SYMBOL_GPL(i2c_hid_ll_driver);
static int get_gpio_pin_state(struct irq_desc *irq_desc)
{
struct gpio_chip *gc = irq_data_get_irq_chip_data(&irq_desc->irq_data);
int value;
/*
* This part of code is borrowed from gpiod_get_raw_value_commit in
* drivers/gpio/gpiolib.c. Ideally, gpiod_get_value_cansleep can be re-used
* instead but there is no API of converting (struct irq_desc *) to
* (struct gpio_desc*).
*/
value = gc->get ? gc->get(gc, irq_desc->irq_data.hwirq) : -EIO;
value = value < 0 ? value : !!value;
return value;
}
static bool interrupt_line_active(struct i2c_hid *ihid)
{
int status = get_gpio_pin_state(ihid->irq_desc);
struct i2c_client *client = ihid->client;
if (status < 0) {
dev_dbg_ratelimited(&client->dev,
"Failed to get GPIO Interrupt line status for %s",
client->name);
return false;
}
/*
* According to Windows Precsiontion Touchpad's specs
* https://docs.microsoft.com/en-us/windows-hardware/design/component-guidelines/windows-precision-touchpad-device-bus-connectivity,
* GPIO Interrupt Assertion Leve could be either ActiveLow or
* ActiveHigh.
*/
if (ihid->irq_trigger_type & IRQF_TRIGGER_LOW)
return !status;
return status;
}
static int i2c_hid_polling_thread(void *i2c_hid)
{
struct i2c_hid *ihid = i2c_hid;
unsigned int polling_interval_idle;
while (!kthread_should_stop()) {
while (interrupt_line_active(i2c_hid) &&
!test_bit(I2C_HID_READ_PENDING, &ihid->flags) &&
!kthread_should_stop()) {
i2c_hid_get_input(ihid);
usleep_range(polling_interval_active_us,
polling_interval_active_us + 100);
}
/*
* re-calculate polling_interval_idle
* so the module parameters polling_interval_idle_ms can be
* changed dynamically through sysfs as polling_interval_active_us
*/
polling_interval_idle = polling_interval_idle_ms * 1000;
usleep_range(polling_interval_idle,
polling_interval_idle + 1000);
}
return 0;
}
static int i2c_hid_init_polling(struct i2c_hid *ihid)
{
struct i2c_client *client = ihid->client;
ihid->irq_trigger_type = irq_get_trigger_type(client->irq);
if (!ihid->irq_trigger_type) {
dev_dbg(&client->dev,
"Failed to get GPIO Interrupt Assertion Level, could not enable polling mode for %s",
client->name);
return -EINVAL;
}
ihid->polling_thread = kthread_create(i2c_hid_polling_thread, ihid,
"I2C HID polling thread");
if (IS_ERR(ihid->polling_thread)) {
dev_err(&client->dev, "Failed to create I2C HID polling thread");
return PTR_ERR(ihid->polling_thread);
}
ihid->irq_desc = irq_to_desc(client->irq);
wake_up_process(ihid->polling_thread);
return 0;
}
static int i2c_hid_init_irq(struct i2c_client *client)
{
struct i2c_hid *ihid = i2c_get_clientdata(client);
unsigned long irqflags = 0;
int ret;
dev_dbg(&client->dev, "Requesting IRQ: %d\n", client->irq);
if (!irq_get_trigger_type(client->irq))
irqflags = IRQF_TRIGGER_LOW;
ret = request_threaded_irq(client->irq, NULL, i2c_hid_irq,
irqflags | 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, client->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) */
if (i2c_hid_get_dmi_i2c_hid_desc_override(client->name)) {
i2c_hid_dbg(ihid, "Using a HID descriptor override\n");
ihid->hdesc =
*i2c_hid_get_dmi_i2c_hid_desc_override(client->name);
} else {
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);