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Date: Thu, 4 Oct 2012 11:16:17 +0200
From: Benjamin Tissoires <benjamin.tissoires@...il.com>
To: Dmitry Torokhov <dmitry.torokhov@...il.com>
Cc: 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
Hi Dmitry,
thanks for the review.
On Wed, Oct 3, 2012 at 6:43 PM, Dmitry Torokhov
<dmitry.torokhov@...il.com> wrote:
> Hi Benjamin,
>
> A few random comments...
>
> On Fri, Sep 14, 2012 at 03:41:43PM +0200, benjamin.tissoires 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_hid? And elsewhere s/i2chid/i2c_hid/ maybe?
Yes, maybe. It's more easier to read. I chose to name it without the
underscore to be closer to the usbhid driver, but it's harder to read.
>
>> + 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);
>
> Why not simply
>
> dev_XXX(&ihid->client->dev, "%*ph\n", n, buf);
Indeed, it's far more simple.... sorry.
>
>> +}
>> +
>> +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;
>
> How can this happen?
It shouldn't. An excess of checking while writing the first version,
and now it's useless.
>
>> +
>> + cmd = kmalloc(args_len + sizeof(union command), GFP_KERNEL);
>> + if (!cmd)
>> + return -ENOMEM;
>
> Can we have several commands pending at once? If not maybe use suffcient
> preallocated buffer in i2c_hid structure?
At first, I allocated it statically. However, due to some outputs
commands, it's harder to get the exact maximum of this command.
The set_report has the following command: fill the set report + fill
the data register (with headers and size) with the report.
By writing it, I realize that I should be able to get a maximum buffer length...
>
>> +
>> + 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);
>
> Agaion, try using '%*ph' format specifier instead.
ok
>
>> + }
>> +
>> + 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);
>
> Why do you need to take this lock? Overall I am not sure why we take
> spinlockn this driver when we use atomics to manipulate flags.
Right. The spinlocks were there to protect against the reset command
that must be synchronous.
By re-reading the code, I think I can handle it without the need of spinlocks.
So I'll drop them in v2.
>
>> + }
>> +
>> + 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__);
>
> Why do we have error level messages with debug? I know dev_dbg is
> compiled out if !DEBUG, but there must be a better way. Maybe define
> i2c_hid_dbg() via dev_printk() and also check debug condition there?
>
ooops....
yep, the i2c_hid_dbg is far better. Will do it.
>> + }
>> +
>> + 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;
>> + }
>> +
>> + 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;
>> +
>> + if (debug)
>> + dev_err(&client->dev, "resetting...\n");
>> +
>> + 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);
>
> Why this lock? What does it protect? You just dropped it and make a
> decision on something that you retrieved while holding the lock. But now
> that you dropped it the condition could change by the time you get to
> test it, so why bother?
As mentioned above, the lock was more against the RESET_PENDING. I
consider that once the device is started, we can handle the input
reports.
Anyway, as mentioned above, I'll try to remove them in v2, it will be
more simple.
>
>> +
>> + 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",
>
> %*ph again.
Ok.
>
>> + __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;
>
> How?
will drop it.
>
>> +
>> + hid->claimed = 0;
>
> Should it be here and not in core?
This is a line that was copied/pasted from usbhid. I'll check how can
I do that without interfering with core.
>
>> +
>> + 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) {o
>
> Maybe !client->irq?
I thought that irqs should be positive or null numbers. This can be
easily changed.
>
>> + 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;
>> +
>> + 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
>>
>
> Thanks.
Thanks to you Dmitry.
I will try to post the v2 soon.
Cheers,
Benjamin
>
> --
> Dmitry
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