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Message-ID: <CAM=Q2cuVa9yLY7-nRz26OYktgM3i+dOfDa8vVznwMVrs9pH5sg@mail.gmail.com>
Date: Wed, 3 Oct 2012 11:35:24 +0530
From: Shubhrajyoti Datta <omaplinuxkernel@...il.com>
To: "benjamin.tissoires" <benjamin.tissoires@...il.com>
Cc: Dmitry Torokhov <dmitry.torokhov@...il.com>,
Jiri Kosina <jkosina@...e.cz>,
Stephane Chatty <chatty@...c.fr>, fabien.andre@...il.com,
scott.liu@....com.tw, Jean Delvare <khali@...ux-fr.org>,
Ben Dooks <ben-linux@...ff.org>,
Wolfram Sang <w.sang@...gutronix.de>,
linux-i2c@...r.kernel.org, linux-input@...r.kernel.org,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH v1] i2c-hid: introduce HID over i2c specification implementation
On Fri, Sep 14, 2012 at 7:11 PM, benjamin.tissoires
<benjamin.tissoires@...il.com> wrote:
> From: Benjamin Tissoires <benjamin.tissoires@...c.fr>
>
> Microsoft published the protocol specification of HID over i2c:
> http://msdn.microsoft.com/en-us/library/windows/hardware/hh852380.aspx
>
> This patch introduces an implementation of this protocol.
>
> This implementation does not includes the ACPI part of the specification.
> This will come when ACPI 5.0 devices will be available.
>
> Once the ACPI part will be done, OEM will not have to declare HID over I2C
> devices in their platform specific driver.
>
> Signed-off-by: Benjamin Tissoires <benjamin.tissoires@...c.fr>
> ---
>
> Hi,
>
> this is finally my first implementation of HID over I2C.
>
> This has been tested on an Elan Microelectronics HID over I2C device, with
> a Samsung Exynos 4412 board.
>
> Any comments are welcome.
>
> Cheers,
> Benjamin
>
> drivers/i2c/Kconfig | 8 +
> drivers/i2c/Makefile | 1 +
> drivers/i2c/i2c-hid.c | 1027 +++++++++++++++++++++++++++++++++++++++++++
> include/linux/i2c/i2c-hid.h | 35 ++
> 4 files changed, 1071 insertions(+)
> create mode 100644 drivers/i2c/i2c-hid.c
> create mode 100644 include/linux/i2c/i2c-hid.h
>
> diff --git a/drivers/i2c/Kconfig b/drivers/i2c/Kconfig
> index 5a3bb3d..5adf65a 100644
> --- a/drivers/i2c/Kconfig
> +++ b/drivers/i2c/Kconfig
> @@ -47,6 +47,14 @@ config I2C_CHARDEV
> This support is also available as a module. If so, the module
> will be called i2c-dev.
>
> +config I2C_HID
> + tristate "HID over I2C bus"
> + help
> + Say Y here to use the HID over i2c protocol implementation.
> +
> + This support is also available as a module. If so, the module
> + will be called i2c-hid.
> +
> config I2C_MUX
> tristate "I2C bus multiplexing support"
> help
> diff --git a/drivers/i2c/Makefile b/drivers/i2c/Makefile
> index beee6b2..8f38116 100644
> --- a/drivers/i2c/Makefile
> +++ b/drivers/i2c/Makefile
> @@ -6,6 +6,7 @@ obj-$(CONFIG_I2C_BOARDINFO) += i2c-boardinfo.o
> obj-$(CONFIG_I2C) += i2c-core.o
> obj-$(CONFIG_I2C_SMBUS) += i2c-smbus.o
> obj-$(CONFIG_I2C_CHARDEV) += i2c-dev.o
> +obj-$(CONFIG_I2C_HID) += i2c-hid.o
> obj-$(CONFIG_I2C_MUX) += i2c-mux.o
> obj-y += algos/ busses/ muxes/
>
> diff --git a/drivers/i2c/i2c-hid.c b/drivers/i2c/i2c-hid.c
> new file mode 100644
> index 0000000..eb17d8c
> --- /dev/null
> +++ b/drivers/i2c/i2c-hid.c
> @@ -0,0 +1,1027 @@
> +/*
> + * HID over I2C protocol implementation
> + *
> + * Copyright (c) 2012 Benjamin Tissoires <benjamin.tissoires@...il.com>
> + * Copyright (c) 2012 Ecole Nationale de l'Aviation Civile, France
> + *
> + * This code is partly based on "USB HID support for Linux":
> + *
> + * Copyright (c) 1999 Andreas Gal
> + * Copyright (c) 2000-2005 Vojtech Pavlik <vojtech@...e.cz>
> + * Copyright (c) 2005 Michael Haboustak <mike-@...ci.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/irq.h>
> +#include <linux/gpio.h>
> +#include <linux/interrupt.h>
> +#include <linux/input.h>
> +#include <linux/delay.h>
> +#include <linux/slab.h>
> +#include <linux/pm.h>
> +
> +#include <linux/i2c/i2c-hid.h>
> +
> +#include <linux/hid.h>
> +#include <linux/hiddev.h>
> +#include <linux/hidraw.h>
> +
> +#define DRIVER_NAME "i2chid"
> +#define DRIVER_DESC "HID over I2C core driver"
> +
> +#define I2C_HID_COMMAND_TRIES 3
> +
> +/* flags */
> +#define I2C_HID_STARTED (1 << 0)
> +#define I2C_HID_OUT_RUNNING (1 << 1)
> +#define I2C_HID_IN_RUNNING (1 << 2)
> +#define I2C_HID_RESET_PENDING (1 << 3)
> +#define I2C_HID_SUSPENDED (1 << 4)
> +
> +#define I2C_HID_PWR_ON 0x00
> +#define I2C_HID_PWR_SLEEP 0x01
> +
> +/* debug option */
> +static bool debug = false;
> +module_param(debug, bool, 0444);
> +MODULE_PARM_DESC(debug, "print a lot of debug informations");
> +
> +struct i2chid_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;
> +} __packed;
> +
> +struct i2chid_cmd {
> + enum {
> + /* fecth HID descriptor */
> + HID_DESCR_CMD,
> +
> + /* fetch report descriptors */
> + HID_REPORT_DESCR_CMD,
> +
> + /* commands */
> + HID_RESET_CMD,
> + HID_GET_REPORT_CMD,
> + HID_SET_REPORT_CMD,
> + HID_GET_IDLE_CMD,
> + HID_SET_IDLE_CMD,
> + HID_GET_PROTOCOL_CMD,
> + HID_SET_PROTOCOL_CMD,
> + HID_SET_POWER_CMD,
> +
> + /* read/write data register */
> + HID_DATA_CMD,
> + } name;
> + 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(name_, opcode_) \
> + .name = name_, .opcode = opcode_, .length = 4, \
> + .registerIndex = offsetof(struct i2chid_desc, wCommandRegister)
> +
> +static const struct i2chid_cmd cmds[] = {
> + { I2C_HID_CMD(HID_RESET_CMD, 0x01), .wait = true },
> + { I2C_HID_CMD(HID_GET_REPORT_CMD, 0x02) },
> + { I2C_HID_CMD(HID_SET_REPORT_CMD, 0x03) },
> + { I2C_HID_CMD(HID_GET_IDLE_CMD, 0x04) },
> + { I2C_HID_CMD(HID_SET_IDLE_CMD, 0x05) },
> + { I2C_HID_CMD(HID_GET_PROTOCOL_CMD, 0x06) },
> + { I2C_HID_CMD(HID_SET_PROTOCOL_CMD, 0x07) },
> + { I2C_HID_CMD(HID_SET_POWER_CMD, 0x08) },
> +
> + {.name = HID_DESCR_CMD,
> + .length = 2},
> +
> + {.name = HID_REPORT_DESCR_CMD,
> + .registerIndex = offsetof(struct i2chid_desc, wReportDescRegister),
> + .opcode = 0x00,
> + .length = 2},
> +
> + {.name = HID_DATA_CMD,
> + .registerIndex = offsetof(struct i2chid_desc, wDataRegister),
> + .opcode = 0x00,
> + .length = 2},
> +
> + {}, /* terminating */
> +};
> +
> +/* The main device structure */
> +struct i2chid {
> + struct i2c_client *client; /* i2c client */
> + struct hid_device *hid; /* pointer to corresponding HID dev */
> + union {
> + __u8 hdesc_buffer[sizeof(struct i2chid_desc)];
> + struct i2chid_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 */
> +
> + spinlock_t flock; /* flags spinlock */
> + unsigned long flags; /* device flags */
> +
> + int irq; /* the interrupt line irq */
> +
> + wait_queue_head_t wait; /* For waiting the interrupt */
> +};
> +
> +void i2chid_print_buffer(struct i2chid *ihid, u8 *buf, unsigned int n)
> +{
> + int i;
> + char *string = kzalloc((n*3+1)*sizeof(char), GFP_KERNEL);
> + char tmpbuf[4] = "";
> +
> + for (i = 0; i < n; ++i) {
> + sprintf(tmpbuf, "%02x ", buf[i] & 0xFF);
> + strcat(string, tmpbuf);
> + }
> +
> + dev_err(&ihid->client->dev, "%s\n", string);
> + kfree(string);
> +}
> +
> +static int __i2chid_command(struct i2c_client *client, int command, u8 reportID,
> + u8 reportType, u8 *args, int args_len,
> + unsigned char *buf_recv, int data_len)
> +{
> + struct i2chid *ihid = i2c_get_clientdata(client);
> + union command *cmd;
> + unsigned char *rec_buf = buf_recv;
> + int ret;
> + int tries = I2C_HID_COMMAND_TRIES;
> + int length = 0;
> + struct i2c_msg msg[2];
> + int msg_num = 0;
> + int i;
> + bool wait = false;
> +
> + if (WARN_ON(!ihid))
> + return -ENODEV;
> +
> + cmd = kmalloc(args_len + sizeof(union command), GFP_KERNEL);
> + if (!cmd)
> + return -ENOMEM;
> +
> + for (i = 0; cmds[i].length; i++) {
> + unsigned int registerIndex;
> +
> + if (cmds[i].name != command)
> + continue;
> +
> + registerIndex = cmds[i].registerIndex;
> + cmd->data[0] = ihid->hdesc_buffer[registerIndex];
> + cmd->data[1] = ihid->hdesc_buffer[registerIndex + 1];
> + cmd->c.opcode = cmds[i].opcode;
> + length = cmds[i].length;
> + wait = cmds[i].wait;
> + }
> +
> + /* special case for HID_DESCR_CMD */
> + if (command == HID_DESCR_CMD)
> + cmd->c.reg = ihid->wHIDDescRegister;
> +
> + cmd->c.reportTypeID = reportID | reportType << 4;
> +
> + memcpy(cmd->data + length, args, args_len);
> + length += args_len;
> +
> + if (debug) {
> + char tmpstr[4] = "";
> + char strbuf[50] = "";
> + int i;
> + for (i = 0; i < length; i++) {
> + sprintf(tmpstr, "%02x ", cmd->data[i] & 0xFF);
> + strcat(strbuf, tmpstr);
> + }
> + dev_err(&client->dev, "%s, cmd=%s\n", __func__, strbuf);
> + }
> +
> + msg[0].addr = client->addr;
> + msg[0].flags = client->flags & I2C_M_TEN;
> + msg[0].len = length;
> + msg[0].buf = (char *) cmd->data;
> + 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 = rec_buf;
> +
> + msg_num = data_len > 0 ? 2 : 1;
> +
> + if (wait) {
> + spin_lock_irq(&ihid->flock);
> + set_bit(I2C_HID_RESET_PENDING, &ihid->flags);
> + spin_unlock_irq(&ihid->flock);
> + }
> +
> + do {
> + ret = i2c_transfer(client->adapter, msg, msg_num);
> + if (ret > 0)
> + break;
> + tries--;
> + dev_dbg(&client->dev, "retrying i2chid_command:%d (%d)\n",
> + command, tries);
> + } while (tries > 0);
> +
> + if (wait && ret > 0) {
> + if (debug)
> + dev_err(&client->dev, "%s: waiting....\n", __func__);
> + if (!wait_event_timeout(ihid->wait,
> + !test_bit(I2C_HID_RESET_PENDING, &ihid->flags),
> + msecs_to_jiffies(5000)))
> + ret = -ENODATA;
> + if (debug)
> + dev_err(&client->dev, "%s: finished.\n", __func__);
> + }
> +
> + kfree(cmd);
> +
> + return ret > 0 ? ret != msg_num : ret;
> +}
> +
> +static int i2chid_command(struct i2c_client *client, int command,
> + unsigned char *buf_recv, int data_len)
> +{
> + return __i2chid_command(client, command, 0, 0, NULL, 0,
> + buf_recv, data_len);
> +}
> +
> +static int i2chid_get_report(struct i2c_client *client, u8 reportType,
> + u32 reportID, unsigned char *buf_recv, int data_len)
> +{
> + struct i2chid *ihid = i2c_get_clientdata(client);
> + u8 args[6];
> + int ret;
> + int args_len = 0;
> + u16 readRegister = ihid->hdesc.wDataRegister;
> +
> + if (debug)
> + dev_err(&client->dev, "%s\n", __func__);
> +
> + if (reportID >= 15) {
> + args[args_len++] = (reportID >> 0) & 0xFF;
> + args[args_len++] = (reportID >> 8) & 0xFF;
> + args[args_len++] = (reportID >> 16) & 0xFF;
> + args[args_len++] = (reportID >> 24) & 0xFF;
> + reportID = 0x0F;
> + }
> +
> + args[args_len++] = readRegister & 0xff;
> + args[args_len++] = (readRegister >> 8) & 0xff;
> +
> + ret = __i2chid_command(client, HID_GET_REPORT_CMD, reportID & 0x0F,
> + reportType, args, args_len, buf_recv, data_len);
> + if (ret) {
> + dev_err(&client->dev, "HID_GET_REPORT_CMD Fail\n");
> + return -EINVAL;
> + }
> +
> + return 0;
> +}
> +
> +static int i2chid_set_report(struct i2c_client *client, u8 reportType,
> + u32 reportID, unsigned char *buf, int data_len)
> +{
> + struct i2chid *ihid = i2c_get_clientdata(client);
> + u8 *args;
> + int ret;
> + u16 dataRegister = ihid->hdesc.wDataRegister;
> + int args_len = (reportID >= 15 ? 4 : 0) +
> + 2 /* dataRegister */ +
> + 2 /* size */ +
> + data_len;
> + int index = 0;
> +
> + if (debug)
> + dev_err(&client->dev, "%s\n", __func__);
> +
> + args = kmalloc(args_len, GFP_KERNEL);
> +
> + if (reportID >= 15) {
> + args[index++] = (reportID >> 0) & 0xFF;
> + args[index++] = (reportID >> 8) & 0xFF;
> + args[index++] = (reportID >> 16) & 0xFF;
> + args[index++] = (reportID >> 24) & 0xFF;
> + reportID = 0x0F;
> + }
> +
> + args[index++] = dataRegister & 0xff;
> + args[index++] = (dataRegister >> 8) & 0xff;
> +
> + args[index++] = data_len & 0xff;
> + args[index++] = (data_len >> 8) & 0xff;
> +
> + memcpy(&args[index], buf, data_len);
> +
> + ret = __i2chid_command(client, HID_SET_REPORT_CMD, reportID & 0x0F,
> + reportType, args, args_len, NULL, 0);
> + if (ret) {
> + dev_err(&client->dev, "HID_SET_REPORT_CMD Fail\n");
> + return -EINVAL;
> + }
> +
> + kfree(args);
> + return data_len;
> +}
> +
> +static int i2chid_set_power(struct i2c_client *client, int power_state)
> +{
> + int ret;
> +
> + if (debug)
> + dev_err(&client->dev, "%s\n", __func__);
> +
> + ret = __i2chid_command(client, HID_SET_POWER_CMD, power_state & 0x01,
> + 0, NULL, 0, NULL, 0);
> + if (ret) {
> + dev_err(&client->dev, "HID_SET_POWER_CMD Fail\n");
> + return -EINVAL;
may be errors can be passed on.
> + }
> +
> + return 0;
> +}
> +
> +static int i2chid_hwreset(struct i2c_client *client)
> +{
> + uint8_t buf_recv[79];
> + int ret;
> +
> + if (debug)
> + dev_err(&client->dev, "%s\n", __func__);
> +
> + ret = i2chid_set_power(client, I2C_HID_PWR_ON);
> + if (ret)
> + return -EINVAL;
why not just pass on the error?
> +
> + if (debug)
> + dev_err(&client->dev, "resetting...\n");
this is a little uncustomary.
May be consider bdg
> +
> + ret = i2chid_command(client, HID_RESET_CMD, buf_recv, 0);
> + if (ret) {
> + dev_err(&client->dev, "HID_RESET_CMD Fail\n");
> + return -EINVAL;
> + }
> +
> + ret = i2c_master_recv(client, buf_recv, 2);
> + if (ret != 2 || (buf_recv[0] != 0 && buf_recv[1] != 0)) {
> + dev_err(&client->dev,
> + "HID_RESET_CMD Failed: got %02x %02x, size=%d\n",
> + buf_recv[0], buf_recv[1], ret);
> +
> + i2chid_set_power(client, I2C_HID_PWR_SLEEP);
> + return -EINVAL;
> + }
> + return 0;
> +}
> +
> +static bool i2chid_get_input(struct i2chid *ihid)
> +{
> + int ret;
> + int size = ihid->hdesc.wMaxInputLength;
> +
> + ret = i2c_master_recv(ihid->client, ihid->inbuf, size);
> + if (ret != size) {
> + dev_err(&ihid->client->dev, "%s: got %d data instead of %d\n",
> + __func__, ret, size);
> + return false;
> + }
> +
> + if (debug)
> + i2chid_print_buffer(ihid, ihid->inbuf, size);
> +
> + ret = hid_input_report(ihid->hid, HID_INPUT_REPORT, ihid->inbuf + 2,
> + size - 2, 1);
> + if (ret)
> + return false;
> +
> + return true;
> +}
> +
> +static irqreturn_t i2chid_irq(int irq, void *dev_id)
> +{
> + struct i2chid *ihid = dev_id;
> + int ready;
> +
> + if (!ihid)
> + return IRQ_HANDLED;
> +
> + spin_lock_irq(&ihid->flock);
> + if (test_and_clear_bit(I2C_HID_RESET_PENDING, &ihid->flags)) {
> + spin_unlock_irq(&ihid->flock);
> +
> + wake_up(&ihid->wait);
> + return IRQ_HANDLED;
> + }
> +
> + ready = test_bit(I2C_HID_STARTED, &ihid->flags);
> + spin_unlock_irq(&ihid->flock);
> +
> + if (ready)
> + i2chid_get_input(ihid);
> +
> + return IRQ_HANDLED;
> +}
> +
> +static int i2chid_get_report_length(struct hid_report *report)
> +{
> + return ((report->size - 1) >> 3) + 1 +
> + report->device->report_enum[report->type].numbered + 2;
> +}
> +
> +void i2chid_init_report(struct hid_report *report)
> +{
> + struct hid_device *hid = report->device;
> + struct i2c_client *client = hid->driver_data;
> + struct i2chid *ihid = i2c_get_clientdata(client);
> + unsigned int size, ret_size;
> +
> + size = i2chid_get_report_length(report);
> + i2chid_get_report(client,
> + report->type == HID_FEATURE_REPORT ? 0x03 : 0x01,
> + report->id, ihid->inbuf, size);
> +
> + if (debug)
> + i2chid_print_buffer(ihid, ihid->inbuf, size);
> +
> + ret_size = ihid->inbuf[0] | (ihid->inbuf[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, ihid->inbuf + 2, size - 2, 1);
> +}
> +
> +/*
> + * Initialize all reports
> + */
> +void i2chid_init_reports(struct hid_device *hid)
> +{
> + struct hid_report *report;
> +
> + list_for_each_entry(report,
> + &hid->report_enum[HID_INPUT_REPORT].report_list, list)
> + i2chid_init_report(report);
> +
> + list_for_each_entry(report,
> + &hid->report_enum[HID_FEATURE_REPORT].report_list, list)
> + i2chid_init_report(report);
> +}
> +
> +/*
> + * Traverse the supplied list of reports and find the longest
> + */
> +static void i2chid_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 = i2chid_get_report_length(report);
> + if (*max < size)
> + *max = size;
> + }
> +}
> +
> +static int i2chid_alloc_buffers(struct i2chid *ihid)
> +{
> + ihid->inbuf = kzalloc(ihid->bufsize, GFP_KERNEL);
> +
> + if (!ihid->inbuf)
> + return -1;
> +
> + return 0;
> +}
> +
> +static void i2chid_free_buffers(struct i2chid *ihid)
> +{
> + kfree(ihid->inbuf);
> +}
> +
> +static int i2chid_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 i2chid *ihid = i2c_get_clientdata(client);
> + int ret;
> +
> + if (count > ihid->bufsize)
> + count = ihid->bufsize;
> +
> + ret = i2chid_get_report(client,
> + report_type == HID_FEATURE_REPORT ? 0x03 : 0x01,
> + report_number, ihid->inbuf, count);
> +
> + if (ret < 0)
> + return ret;
> +
> + count = ihid->inbuf[0] | (ihid->inbuf[1] << 8);
> +
> + memcpy(buf, ihid->inbuf + 2, count);
> +
> + return count;
> +}
> +
> +static int i2chid_output_raw_report(struct hid_device *hid, __u8 *buf,
> + size_t count, unsigned char report_type)
> +{
> + struct i2c_client *client = hid->driver_data;
> + int ret;
> + int report_id = buf[0];
> +
> + ret = i2chid_set_report(client,
> + report_type == HID_FEATURE_REPORT ? 0x03 : 0x01,
> + report_id, buf, count);
> +
> + return ret;
> +
> +}
> +
> +static int i2chid_fetch_hid_descriptor(struct i2chid *ihid)
> +{
> + struct i2c_client *client = ihid->client;
> + struct i2chid_desc *hdesc = &ihid->hdesc;
> + unsigned int dsize = 0;
> + int ret;
> +
> + /* Fetch the length of HID description, retrieve the 4 first bytes:
> + * bytes 0-1 -> length
> + * bytes 2-3 -> bcdVersion (has to be 1.00) */
> + ret = i2chid_command(client, HID_DESCR_CMD, ihid->hdesc_buffer, 4);
> +
> + if (debug)
> + dev_err(&client->dev,
> + "%s, ihid->hdesc_buffer: %02x %02x %02x %02x\n",
> + __func__,
> + ihid->hdesc_buffer[0],
> + ihid->hdesc_buffer[1],
> + ihid->hdesc_buffer[2],
> + ihid->hdesc_buffer[3]);
> +
> + if (ret) {
> + dev_err(&client->dev, "HID_DESCR_LENGTH_CMD Fail (ret=%d)\n",
> + ret);
> + return -EINVAL;
> + }
> +
> + dsize = le16_to_cpu(hdesc->wHIDDescLength);
> + if (!dsize || dsize > HID_MAX_DESCRIPTOR_SIZE) {
> + dev_err(&client->dev, "weird size of HID descriptor (%u)\n",
> + dsize);
> + return -EINVAL;
> + }
> +
> + /* check bcdVersion == 1.0 */
> + if (le16_to_cpu(hdesc->bcdVersion) != 0x0100) {
> + dev_err(&client->dev,
> + "unexpected HID descriptor bcdVersion (0x%04x)\n",
> + le16_to_cpu(hdesc->bcdVersion));
> + return -EINVAL;
> + }
> +
> + if (debug)
> + dev_err(&client->dev, "Fetching the HID descriptor\n");
> +
> + ret = i2chid_command(client, HID_DESCR_CMD, ihid->hdesc_buffer, dsize);
> + if (ret) {
> + dev_err(&client->dev, "HID_DESCR_CMD Fail\n");
> + return -EINVAL;
> + }
> +
> + if (debug)
> + i2chid_print_buffer(ihid, ihid->hdesc_buffer, dsize);
> +
> + return 0;
> +}
> +
> +static int i2chid_parse(struct hid_device *hid)
> +{
> + struct i2c_client *client = hid->driver_data;
> + struct i2chid *ihid = i2c_get_clientdata(client);
> + struct i2chid_desc *hdesc = &ihid->hdesc;
> + unsigned int rsize = 0;
> + char *rdesc;
> + int ret;
> + int tries = 3;
> +
> + if (debug)
> + dev_err(&client->dev, "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 = i2chid_hwreset(client);
> + if (ret)
> + msleep(1000);
> + } while (tries-- > 0 && ret);
> +
> + if (ret)
> + return ret;
> +
> + rdesc = kmalloc(rsize, GFP_KERNEL);
> +
> + if (!rdesc) {
> + dbg_hid("couldn't allocate rdesc memory\n");
> + return -ENOMEM;
> + }
> +
> + if (debug)
> + dev_err(&client->dev, "asking HID report descriptor\n");
> +
> + ret = i2chid_command(client, HID_REPORT_DESCR_CMD, rdesc, rsize);
> + if (ret) {
> + hid_err(hid, "reading report descriptor failed\n");
> + kfree(rdesc);
> + ret = -ENOMEM;
> + goto err;
> + }
> +
> + if (debug)
> + i2chid_print_buffer(ihid, rdesc, rsize);
> +
> + ret = hid_parse_report(hid, rdesc, rsize);
> + kfree(rdesc);
> + if (ret) {
> + dbg_hid("parsing report descriptor failed\n");
> + goto err;
> + }
> +
> + return 0;
> +err:
> + return ret;
> +}
> +
> +static int i2chid_start(struct hid_device *hid)
> +{
> + struct i2c_client *client = hid->driver_data;
> + struct i2chid *ihid = i2c_get_clientdata(client);
> + int ret;
> +
> + ihid->bufsize = HID_MIN_BUFFER_SIZE;
> + i2chid_find_max_report(hid, HID_INPUT_REPORT, &ihid->bufsize);
> + i2chid_find_max_report(hid, HID_OUTPUT_REPORT, &ihid->bufsize);
> + i2chid_find_max_report(hid, HID_FEATURE_REPORT, &ihid->bufsize);
> +
> + if (ihid->bufsize > HID_MAX_BUFFER_SIZE)
> + ihid->bufsize = HID_MAX_BUFFER_SIZE;
> +
> + if (i2chid_alloc_buffers(ihid)) {
> + ret = -ENOMEM;
> + goto fail;
> + }
> +
> + if (!(hid->quirks & HID_QUIRK_NO_INIT_REPORTS))
> + i2chid_init_reports(hid);
> +
> + return 0;
> +
> +fail:
> + i2chid_free_buffers(ihid);
> + return ret;
> +}
> +
> +static void i2chid_stop(struct hid_device *hid)
> +{
> + struct i2c_client *client = hid->driver_data;
> + struct i2chid *ihid = i2c_get_clientdata(client);
> +
> + if (WARN_ON(!ihid))
> + return;
> +
> + hid->claimed = 0;
> +
> + i2chid_free_buffers(ihid);
> +}
> +
> +static int i2chid_open(struct hid_device *hid)
> +{
> + struct i2c_client *client = hid->driver_data;
> + struct i2chid *ihid = i2c_get_clientdata(client);
> + int ret;
> +
> + if (!hid->open++) {
> + ret = i2chid_set_power(client, I2C_HID_PWR_ON);
> + if (ret) {
> + hid->open--;
> + return -EIO;
> + }
> + spin_lock_irq(&ihid->flock);
> + set_bit(I2C_HID_STARTED, &ihid->flags);
> + spin_unlock_irq(&ihid->flock);
> + }
> + return 0;
> +}
> +
> +static void i2chid_close(struct hid_device *hid)
> +{
> + struct i2c_client *client = hid->driver_data;
> + struct i2chid *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
> + */
> + if (!--hid->open) {
> + spin_lock_irq(&ihid->flock);
> + clear_bit(I2C_HID_STARTED, &ihid->flags);
> + spin_unlock_irq(&ihid->flock);
> +
> + /* Save some power */
> + i2chid_set_power(client, I2C_HID_PWR_SLEEP);
> + }
> +}
> +
> +static int i2chid_power(struct hid_device *hid, int lvl)
> +{
> + struct i2c_client *client = hid->driver_data;
> + int r = 0;
> +
> + if (debug)
> + dev_err(&client->dev, "%s lvl:%d\n", __func__, lvl);
> +
> + switch (lvl) {
> + case PM_HINT_FULLON:
> + r = i2chid_set_power(client, I2C_HID_PWR_ON);
> + break;
> + case PM_HINT_NORMAL:
> + r = i2chid_set_power(client, I2C_HID_PWR_SLEEP);
> + break;
> + }
> + return r;
> +}
> +
> +static int i2chid_hidinput_input_event(struct input_dev *dev, unsigned int type,
> + unsigned int code, int value)
> +{
> + struct hid_device *hid = input_get_drvdata(dev);
> + struct hid_field *field;
> + int offset;
> +
> + if (type == EV_FF)
> + return input_ff_event(dev, type, code, value);
> +
> + if (type != EV_LED)
> + return -1;
> +
> + offset = hidinput_find_field(hid, type, code, &field);
> +
> + if (offset == -1) {
> + hid_warn(dev, "event field not found\n");
> + return -1;
> + }
> +
> + hid_set_field(field, offset, value);
> +
> + return 0;
> +}
> +
> +static struct hid_ll_driver i2c_hid_driver = {
> + .parse = i2chid_parse,
> + .start = i2chid_start,
> + .stop = i2chid_stop,
> + .open = i2chid_open,
> + .close = i2chid_close,
> + .power = i2chid_power,
> + .hidinput_input_event = i2chid_hidinput_input_event,
> +};
> +
> +static int i2chid_init_irq(struct i2c_client *client)
> +{
> + struct i2chid *ihid = i2c_get_clientdata(client);
> + int rc;
> +
> + dev_dbg(&client->dev, "Requesting IRQ: %d\n",
> + client->irq);
> +
> + rc = request_threaded_irq(client->irq, NULL, i2chid_irq,
> + IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
> + DRIVER_NAME, ihid);
> + if (rc < 0) {
> + dev_dbg(&client->dev,
> + "Could not register for %s interrupt, irq = %d,"
> + " rc = %d\n",
> + DRIVER_NAME, client->irq, rc);
> +
> + return rc;
> + }
> +
> + return client->irq;
> +}
> +
> +static int __devinit i2chid_probe(struct i2c_client *client,
> + const struct i2c_device_id *dev_id)
> +{
> + int ret;
> + struct i2chid *ihid;
> + struct hid_device *hid;
> + __u16 hidRegister;
> + unsigned char tmpstr[11];
> + struct i2chid_platform_data *platform_data = client->dev.platform_data;
> +
> + dbg_hid("HID probe called for i2c %d\n", client->addr);
> +
> + if (!platform_data) {
> + dev_err(&client->dev, "HID register address not provided\n");
> + return -EINVAL;
> + }
> +
> + if (client->irq < 1) {
> + dev_err(&client->dev,
> + "HID over i2c has not been provided an Int IRQ\n");
> + return -EINVAL;
> + }
> +
> + ihid = kzalloc(sizeof(struct i2chid), GFP_KERNEL);
> + if (!ihid)
> + return -ENOMEM;
you may consider devm_* function here.
> +
> + i2c_set_clientdata(client, ihid);
> +
> + ihid->client = client;
> + ihid->flags = 0;
> +
> + hidRegister = platform_data->hid_descriptor_address;
> + ihid->wHIDDescRegister = cpu_to_le16(hidRegister);
> +
> + init_waitqueue_head(&ihid->wait);
> + spin_lock_init(&ihid->flock);
> +
> + ret = i2chid_fetch_hid_descriptor(ihid);
> + if (ret < 0)
> + goto err;
> +
> + ihid->irq = i2chid_init_irq(client);
> + if (ihid->irq < 0)
> + goto err;
> +
> + hid = hid_allocate_device();
> + if (IS_ERR(hid)) {
> + ret = -ENOMEM;
> + goto err;
> + }
> +
> + ihid->hid = hid;
> +
> + hid->driver_data = client;
> + hid->ll_driver = &i2c_hid_driver;
> + hid->hid_get_raw_report = i2chid_get_raw_report;
> + hid->hid_output_raw_report = i2chid_output_raw_report;
> + hid->ff_init = hid_pidff_init;
> +#ifdef CONFIG_USB_HIDDEV
> + hid->hiddev_connect = hiddev_connect;
> + hid->hiddev_disconnect = hiddev_disconnect;
> + hid->hiddev_hid_event = hiddev_hid_event;
> + hid->hiddev_report_event = hiddev_report_event;
> +#endif
> + hid->dev.parent = &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(tmpstr, sizeof(tmpstr), " %04X:%04X",
> + hid->vendor, hid->product);
> + strlcpy(hid->name, client->name, sizeof(hid->name));
> + strlcat(hid->name, tmpstr, sizeof(hid->name));
> +
> + 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;
> + }
> +
> + return 0;
> +
> +err_mem_free:
> + hid_destroy_device(hid);
> +
> +err:
> + if (ihid->irq >= 0)
> + free_irq(ihid->irq, ihid);
> +
> + kfree(ihid);
> + return ret;
> +}
> +
> +static int __devexit i2chid_remove(struct i2c_client *client)
> +{
> + struct i2chid *ihid = i2c_get_clientdata(client);
> + struct hid_device *hid;
> +
> + if (WARN_ON(!ihid))
> + return -1;
> +
> + hid = ihid->hid;
> + hid_destroy_device(hid);
> +
> + free_irq(client->irq, ihid);
> +
> + kfree(ihid);
> +
> + return 0;
> +}
> +
> +#ifdef CONFIG_PM_SLEEP
> +static int i2chid_suspend(struct device *dev)
> +{
> + struct i2c_client *client = to_i2c_client(dev);
> + struct i2chid *ihid = i2c_get_clientdata(client);
> +
> + if (device_may_wakeup(&client->dev))
> + enable_irq_wake(ihid->irq);
> +
> + /* Save some power */
> + i2chid_set_power(client, I2C_HID_PWR_SLEEP);
> +
> + return 0;
> +}
> +
> +static int i2chid_resume(struct device *dev)
> +{
> + int ret;
> + struct i2c_client *client = to_i2c_client(dev);
> +
> + ret = i2chid_hwreset(client);
> + if (ret)
> + return ret;
> +
> + if (device_may_wakeup(&client->dev))
> + enable_irq_wake(client->irq);
> +
> + return 0;
> +}
> +#endif
> +
> +static SIMPLE_DEV_PM_OPS(i2chid_pm, i2chid_suspend, i2chid_resume);
> +
> +static const struct i2c_device_id i2chid_id_table[] = {
> + { "i2chid", 0 },
> + { },
> +};
> +MODULE_DEVICE_TABLE(i2c, i2chid_id_table);
> +
> +
> +static struct i2c_driver i2chid_driver = {
> + .driver = {
> + .name = DRIVER_NAME,
> + .owner = THIS_MODULE,
> + .pm = &i2chid_pm,
> + },
> +
> + .probe = i2chid_probe,
> + .remove = __devexit_p(i2chid_remove),
> +
> + .id_table = i2chid_id_table,
> +};
> +
> +module_i2c_driver(i2chid_driver);
> +
> +MODULE_DESCRIPTION(DRIVER_DESC);
> +MODULE_AUTHOR("Benjamin Tissoires <benjamin.tissoires@...il.com>");
> +MODULE_LICENSE("GPL");
> diff --git a/include/linux/i2c/i2c-hid.h b/include/linux/i2c/i2c-hid.h
> new file mode 100644
> index 0000000..6685605
> --- /dev/null
> +++ b/include/linux/i2c/i2c-hid.h
> @@ -0,0 +1,35 @@
> +/*
> + * HID over I2C protocol implementation
> + *
> + * Copyright (c) 2012 Benjamin Tissoires <benjamin.tissoires@...il.com>
> + * Copyright (c) 2012 Ecole Nationale de l'Aviation Civile, France
> + *
> + * 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.
> + */
> +
> +#ifndef __LINUX_I2C_HID_H
> +#define __LINUX_I2C_HID_H
> +
> +#include <linux/types.h>
> +
> +/**
> + * struct i2chid_platform_data - used by hid over i2c implementation.
> + * @hid_descriptor_address: i2c register where the HID descriptor is stored.
> + *
> + * Note that it is the responsibility for the platform driver (or the acpi 5.0
> + * driver) to setup the irq related to the gpio in the struct i2c_board_info.
> + * The platform driver should also setup the gpio according to the device:
> + *
> + * A typical example is the following:
> + * irq = gpio_to_irq(intr_gpio);
> + * hkdk4412_i2c_devs5[0].irq = irq; // store the irq in i2c_board_info
> + * gpio_request(intr_gpio, "elan-irq");
> + * s3c_gpio_setpull(intr_gpio, S3C_GPIO_PULL_UP);
> + */
> +struct i2chid_platform_data {
> + u16 hid_descriptor_address;
> +};
> +
> +#endif /* __LINUX_I2C_HID_H */
> --
> 1.7.11.4
>
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