Re: [PATCH v2] i2c-hid: introduce HID over i2c specification implementation
From: Benjamin Tissoires
Date: Thu Oct 18 2012 - 05:16:08 EST
Hi JJ,
On Thu, Oct 18, 2012 at 11:07 AM, Jian-Jhong Ding <jj_ding@xxxxxxxxxx> wrote:
> Hi Benjamin,
>
> Some suggestions to make the error messages more "human", and a little
> question on the return value of i2c_hid_fetch_hid_descriptor. Please see below:
I fully agree with the more "human" error messages.
However, for i2c_hid_fetch_hid_descriptor return values, I'm affraid I
can't use -EINVAL.
Jean Delvare (one of the i2c maintainers) told in his review of the v1:
"
These should all be -ENODEV in this function
[i2c_hid_fetch_hid_descriptor]: the device isn't what you
expected. EINVAL is for invalid argument.
"
So ENODEV is the right return value.
Anyway, thanks for the review.
Cheers,
Benjamin
>
> Benjamin Tissoires <benjamin.tissoires@xxxxxxxxx> writes:
>> diff --git a/drivers/hid/i2c-hid/i2c-hid.c b/drivers/hid/i2c-hid/i2c-hid.c
>> new file mode 100644
>> index 0000000..8b6c31a
>> --- /dev/null
>> +++ b/drivers/hid/i2c-hid/i2c-hid.c
>> @@ -0,0 +1,990 @@
>> +/*
>> + * HID over I2C protocol implementation
>> + *
>> + * Copyright (c) 2012 Benjamin Tissoires <benjamin.tissoires@xxxxxxxxx>
>> + * 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@xxxxxxx>
>> + * Copyright (c) 2005 Michael Haboustak <mike-@xxxxxxxxxxxx> 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/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/bug.h>
>> +#include <linux/hid.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 = false;
>> +module_param(debug, bool, 0444);
>> +MODULE_PARM_DESC(debug, "print a lot of debug information");
>> +
>> +#define i2c_hid_dbg(ihid, fmt, arg...) \
>> + if (debug) \
>> + dev_printk(KERN_DEBUG, &(ihid)->client->dev, fmt, ##arg)
>> +
>> +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;
>> +} __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_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 const struct i2c_hid_cmd hid_set_power_cmd = { I2C_HID_CMD(0x08) };
>> +/* read/write data register */
>> +static const struct i2c_hid_cmd hid_data_cmd = {
>> + .registerIndex = offsetof(struct i2c_hid_desc, wDataRegister),
>> + .opcode = 0x00,
>> + .length = 2 };
>> +/* write output reports */
>> +static const struct i2c_hid_cmd hid_out_cmd = {
>> + .registerIndex = offsetof(struct i2c_hid_desc,
>> + wOutputRegister),
>> + .opcode = 0x00,
>> + .length = 2 };
>> +
>> +/* 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 *cmdbuf; /* Command buffer */
>> + char *argsbuf; /* Command arguments buffer */
>> +
>> + unsigned long flags; /* device flags */
>> +
>> + int irq; /* the interrupt line irq */
>> +
>> + wait_queue_head_t wait; /* For waiting the interrupt */
>> +};
>> +
>> +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, "hid_get_report_cmd Fail\n");
>
> How about "failed to retrieve report from device.\n"?
>
>> + return -EINVAL;
>> + }
>> +
>> + return 0;
>> +}
>> +
>> +static int i2c_hid_set_report(struct i2c_client *client, u8 reportType,
>> + u8 reportID, unsigned char *buf, size_t data_len)
>> +{
>> + struct i2c_hid *ihid = i2c_get_clientdata(client);
>> + u8 *args = ihid->argsbuf;
>> + int ret;
>> + u16 dataRegister = le16_to_cpu(ihid->hdesc.wDataRegister);
>> + int args_len = (reportID >= 0x0F ? 1 : 0) +
>> + 2 /* dataRegister */ +
>> + 2 /* data_len */ +
>> + data_len;
>> + int index = 0;
>> +
>> + i2c_hid_dbg(ihid, "%s\n", __func__);
>> +
>> + if (reportID >= 0x0F) {
>> + args[index++] = reportID;
>> + reportID = 0x0F;
>> + }
>> +
>> + args[index++] = dataRegister & 0xFF;
>> + args[index++] = dataRegister >> 8;
>> +
>> + /* hidraw already checked that data_len < HID_MAX_BUFFER_SIZE */
>> + args[index++] = data_len & 0xFF;
>> + args[index++] = (data_len >> 8) & 0xFF;
>> +
>> + memcpy(&args[index], buf, data_len);
>> +
>> + ret = __i2c_hid_command(client, &hid_set_report_cmd, reportID,
>> + reportType, args, args_len, NULL, 0);
>> + if (ret) {
>> + dev_err(&client->dev, "hid_set_report_cmd Fail\n");
>
> How about "failed to set a report to device.\n"?
>
>> + return -EINVAL;
>> + }
>> +
>> + return data_len;
>> +}
>> +
>> +static int i2c_hid_write_out_report(struct i2c_client *client,
>> + u8 reportID, unsigned char *buf, size_t data_len)
>> +{
>> + struct i2c_hid *ihid = i2c_get_clientdata(client);
>> + u8 *args = ihid->argsbuf;
>> + int ret;
>> + int args_len = 1 /* reportID */ +
>> + 2 /* data_len */ +
>> + data_len;
>> + int index = 0;
>> +
>> + i2c_hid_dbg(ihid, "%s\n", __func__);
>> +
>> + args[index++] = reportID;
>> +
>> + /* hidraw already checked that data_len < HID_MAX_BUFFER_SIZE */
>> + args[index++] = data_len & 0xFF;
>> + args[index++] = (data_len >> 8) & 0xFF;
>> +
>> + memcpy(&args[index], buf, data_len);
>> +
>> + ret = __i2c_hid_command(client, &hid_out_cmd, 0, 0, args, args_len,
>> + NULL, 0);
>> + if (ret) {
>> + dev_err(&client->dev, "hid_out_cmd Fail\n");
>
> How about "failed to write output report.\n"?
>
>> + return -EINVAL;
>> + }
>> +
>> + 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, "hid_set_power_cmd Fail\n");
>
> How about "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, "hid_reset_cmd Fail\n");
>
> How about "failed to reset device.\n"?
>
>> + i2c_hid_set_power(client, I2C_HID_PWR_SLEEP);
>> + return ret;
>> + }
>> +
>> + return 0;
>> +}
>> +
>> +static int i2c_hid_get_input(struct i2c_hid *ihid)
>> +{
>> + int ret, ret_size;
>> + int size = le16_to_cpu(ihid->hdesc.wMaxInputLength);
>> +
>> + ret = i2c_master_recv(ihid->client, ihid->inbuf, size);
>> + if (ret != size) {
>> + if (ret < 0)
>> + return ret;
>> +
>> + dev_err(&ihid->client->dev, "%s: got %d data instead of %d\n",
>> + __func__, ret, size);
>> + return ret;
>> + }
>> +
>> + 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 0;
>> + }
>> +
>> + if (ret_size > size) {
>> + dev_err(&ihid->client->dev, "%s: incomplete report (%d/%d)\n",
>> + __func__, size, ret_size);
>> + return -EIO;
>> + }
>> +
>> + 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 0;
>> +}
>> +
>> +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);
>> + i2c_hid_get_report(client,
>> + report->type == HID_FEATURE_REPORT ? 0x03 : 0x01,
>> + report->id, buffer, size);
>> +
>> + i2c_hid_dbg(ihid, "report (len=%d): %*ph\n", size, size, ihid->inbuf);
>> +
>> + 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)
>> + return;
>> +
>> + list_for_each_entry(report,
>> + &hid->report_enum[HID_INPUT_REPORT].report_list, list)
>> + i2c_hid_init_report(report, inbuf, ihid->bufsize);
>> +
>> + list_for_each_entry(report,
>> + &hid->report_enum[HID_FEATURE_REPORT].report_list, list)
>> + i2c_hid_init_report(report, inbuf, ihid->bufsize);
>> +
>> + 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 int i2c_hid_alloc_buffers(struct i2c_hid *ihid)
>> +{
>> + /* 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 */
>> + ihid->bufsize; /* report */
>> +
>> + ihid->inbuf = kzalloc(ihid->bufsize, GFP_KERNEL);
>> +
>> + if (!ihid->inbuf)
>> + return -ENOMEM;
>> +
>> + ihid->argsbuf = kzalloc(args_len, GFP_KERNEL);
>> +
>> + if (!ihid->argsbuf) {
>> + kfree(ihid->inbuf);
>> + return -ENOMEM;
>> + }
>> +
>> + ihid->cmdbuf = kzalloc(sizeof(union command) + args_len, GFP_KERNEL);
>> +
>> + if (!ihid->cmdbuf) {
>> + kfree(ihid->inbuf);
>> + kfree(ihid->argsbuf);
>> + return -ENOMEM;
>> + }
>> +
>> + return 0;
>> +}
>> +
>> +static void i2c_hid_free_buffers(struct i2c_hid *ihid)
>> +{
>> + kfree(ihid->inbuf);
>> + kfree(ihid->argsbuf);
>> + kfree(ihid->cmdbuf);
>> + ihid->inbuf = NULL;
>> + ihid->cmdbuf = NULL;
>> + ihid->argsbuf = NULL;
>> +}
>> +
>> +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);
>> + int ret;
>> +
>> + if (count > ihid->bufsize)
>> + count = ihid->bufsize;
>> +
>> + ret = i2c_hid_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 i2c_hid_output_raw_report(struct hid_device *hid, __u8 *buf,
>> + size_t count, unsigned char report_type)
>> +{
>> + struct i2c_client *client = hid->driver_data;
>> + int report_id = buf[0];
>> +
>> + if (report_type == HID_OUTPUT_REPORT)
>> + return i2c_hid_write_out_report(client, report_id, buf, count);
>> +
>> + return i2c_hid_set_report(client,
>> + report_type == HID_FEATURE_REPORT ? 0x03 : 0x01,
>> + report_id, buf, count);
>> +}
>> +
>> +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;
>> + int old_bufsize = ihid->bufsize;
>> +
>> + ihid->bufsize = HID_MIN_BUFFER_SIZE;
>> + i2c_hid_find_max_report(hid, HID_INPUT_REPORT, &ihid->bufsize);
>> + i2c_hid_find_max_report(hid, HID_OUTPUT_REPORT, &ihid->bufsize);
>> + i2c_hid_find_max_report(hid, HID_FEATURE_REPORT, &ihid->bufsize);
>> +
>> + if (ihid->bufsize > old_bufsize || !ihid->inbuf || !ihid->cmdbuf) {
>> + i2c_hid_free_buffers(ihid);
>> +
>> + ret = i2c_hid_alloc_buffers(ihid);
>> +
>> + 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)
>> +{
>> + struct i2c_client *client = hid->driver_data;
>> + struct i2c_hid *ihid = i2c_get_clientdata(client);
>> +
>> + hid->claimed = 0;
>> +
>> + i2c_hid_free_buffers(ihid);
>> +}
>> +
>> +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;
>> +
>> + if (!hid->open++) {
>> + ret = i2c_hid_set_power(client, I2C_HID_PWR_ON);
>> + if (ret) {
>> + hid->open--;
>> + return -EIO;
>> + }
>> + 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);
>> +
>> + /* protecting hid->open to make sure we don't restart
>> + * data acquistion due to a resumption we no longer
>> + * care about
>> + */
>> + if (!--hid->open) {
>> + clear_bit(I2C_HID_STARTED, &ihid->flags);
>> +
>> + /* Save some power */
>> + i2c_hid_set_power(client, I2C_HID_PWR_SLEEP);
>> + }
>> +}
>> +
>> +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);
>> + int ret = 0;
>> +
>> + i2c_hid_dbg(ihid, "%s lvl:%d\n", __func__, lvl);
>> +
>> + switch (lvl) {
>> + case PM_HINT_FULLON:
>> + ret = i2c_hid_set_power(client, I2C_HID_PWR_ON);
>> + break;
>> + case PM_HINT_NORMAL:
>> + ret = i2c_hid_set_power(client, I2C_HID_PWR_SLEEP);
>> + break;
>> + }
>> + return ret;
>> +}
>> +
>> +static int i2c_hid_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_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,
>> + .hidinput_input_event = i2c_hid_hidinput_input_event,
>> +};
>> +
>> +static int __devinit 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", client->irq);
>> +
>> + ret = request_threaded_irq(client->irq, NULL, i2c_hid_irq,
>> + IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
>> + client->name, ihid);
>> + if (ret < 0) {
>> + dev_dbg(&client->dev,
>> + "Could not register for %s interrupt, irq = %d,"
>> + " ret = %d\n",
>> + client->name, client->irq, ret);
>> +
>> + return ret;
>> + }
>> +
>> + ihid->irq = client->irq;
>> +
>> + return 0;
>> +}
>> +
>> +static int __devinit 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;
>> +
>> + /* 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 = i2c_hid_command(client, &hid_descr_cmd, ihid->hdesc_buffer, 4);
>> +
>> + i2c_hid_dbg(ihid, "%s, ihid->hdesc_buffer: %*ph\n",
>> + __func__, 4, ihid->hdesc_buffer);
>> +
>> + if (ret) {
>> + dev_err(&client->dev, "HID_DESCR_LENGTH_CMD Fail (ret=%d)\n",
>
> How about "failed to get descriptor length (ret = %d).\n"?
>
>> + ret);
>> + return -ENODEV;
>
> In this function, would it be more approriate to 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 -ENODEV;
> -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 -ENODEV;
> -EINVAL?
>> + }
>> +
>> + i2c_hid_dbg(ihid, "Fetching the HID descriptor\n");
>> +
>> + ret = i2c_hid_command(client, &hid_descr_cmd, ihid->hdesc_buffer,
>> + dsize);
>> + if (ret) {
>> + dev_err(&client->dev, "hid_descr_cmd Fail\n");
>
> How about "failed to fetch HID descriptor.\n"?
>
>> + return -ENODEV;
> -EINVAL?
>
> Thanks,
> -JJ
>
>> + }
>> +
>> + i2c_hid_dbg(ihid, "HID Descriptor: %*ph\n", dsize, ihid->hdesc_buffer);
>> +
>> + return 0;
>> +}
>> +
--
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