Re: [PATCH 04/11] HID: logitech-dj: remove hidinput_input_event

[Benjamin Tissoires <benjamin.tissoires@gmail.com>]

On Mon, Feb 3, 2014 at 11:06 AM, David Herrmann <dh.herrmann@gmail.com> wrote:
> Hi
>
> On Sun, Feb 2, 2014 at 5:50 AM, Benjamin Tissoires
> <benjamin.tissoires@redhat.com> wrote:
>> hid-logitech-dj uses its own ->hidinput_input_event() instead of
>> the generic binding in hid-input.
>> Moving the handling of LEDs towards logi_dj_output_hidraw_report()
>> allows two things:
>> - remove hidinput_input_event in struct hid_device
>> - hidraw user space programs can also set the LEDs
>>
>> Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
>> ---
>>  drivers/hid/hid-logitech-dj.c | 99 +++++++++++++++----------------------------
>>  1 file changed, 35 insertions(+), 64 deletions(-)
>>
>> diff --git a/drivers/hid/hid-logitech-dj.c b/drivers/hid/hid-logitech-dj.c
>> index f45279c..61d2bbf 100644
>> --- a/drivers/hid/hid-logitech-dj.c
>> +++ b/drivers/hid/hid-logitech-dj.c
>> @@ -44,14 +44,6 @@ static const char kbd_descriptor[] = {
>>         0x19, 0xE0,             /*   USAGE_MINIMUM (Left Control)   */
>>         0x29, 0xE7,             /*   USAGE_MAXIMUM (Right GUI)      */
>>         0x81, 0x02,             /*   INPUT (Data,Var,Abs)       */
>> -       0x95, 0x05,             /*   REPORT COUNT (5)           */
>> -       0x05, 0x08,             /*   USAGE PAGE (LED page)      */
>> -       0x19, 0x01,             /*   USAGE MINIMUM (1)          */
>> -       0x29, 0x05,             /*   USAGE MAXIMUM (5)          */
>> -       0x91, 0x02,             /*   OUTPUT (Data, Variable, Absolute)  */
>> -       0x95, 0x01,             /*   REPORT COUNT (1)           */
>> -       0x75, 0x03,             /*   REPORT SIZE (3)            */
>> -       0x91, 0x01,             /*   OUTPUT (Constant)          */
>>         0x95, 0x06,             /*   REPORT_COUNT (6)           */
>>         0x75, 0x08,             /*   REPORT_SIZE (8)            */
>>         0x15, 0x00,             /*   LOGICAL_MINIMUM (0)        */
>> @@ -60,6 +52,18 @@ static const char kbd_descriptor[] = {
>>         0x19, 0x00,             /*   USAGE_MINIMUM (no event)       */
>>         0x2A, 0xFF, 0x00,       /*   USAGE_MAXIMUM (reserved)       */
>>         0x81, 0x00,             /*   INPUT (Data,Ary,Abs)       */
>> +       0x85, 0x0e,             /* REPORT_ID (14)               */
>> +       0x05, 0x08,             /*   USAGE PAGE (LED page)      */
>> +       0x95, 0x05,             /*   REPORT COUNT (5)           */
>> +       0x75, 0x01,             /*   REPORT SIZE (1)            */
>> +       0x15, 0x00,             /*   LOGICAL_MINIMUM (0)        */
>> +       0x25, 0x01,             /*   LOGICAL_MAXIMUM (1)        */
>> +       0x19, 0x01,             /*   USAGE MINIMUM (1)          */
>> +       0x29, 0x05,             /*   USAGE MAXIMUM (5)          */
>> +       0x91, 0x02,             /*   OUTPUT (Data, Variable, Absolute)  */
>> +       0x95, 0x01,             /*   REPORT COUNT (1)           */
>> +       0x75, 0x03,             /*   REPORT SIZE (3)            */
>> +       0x91, 0x01,             /*   OUTPUT (Constant)          */
>>         0xC0
>>  };
>>
>> @@ -544,10 +548,30 @@ static int logi_dj_output_hidraw_report(struct hid_device *hid, u8 * buf,
>>                                         size_t count,
>>                                         unsigned char report_type)
>>  {
>> -       /* Called by hid raw to send data */
>> -       dbg_hid("%s\n", __func__);
>> +       struct dj_device *djdev = hid->driver_data;
>> +       struct dj_receiver_dev *djrcv_dev = djdev->dj_receiver_dev;
>> +       u8 *out_buf;
>> +       int ret;
>>
>> -       return 0;
>> +       if (buf[0] != REPORT_TYPE_LEDS)
>> +               return -EINVAL;
>> +
>> +       out_buf = kzalloc(DJREPORT_SHORT_LENGTH, GFP_ATOMIC);
>> +       if (!out_buf)
>> +               return -ENOMEM;
>> +
>> +       if (count < DJREPORT_SHORT_LENGTH - 2)
>> +               count = DJREPORT_SHORT_LENGTH - 2;
>> +
>> +       out_buf[0] = REPORT_ID_DJ_SHORT;
>> +       out_buf[1] = djdev->device_index;
>> +       memcpy(out_buf + 2, buf, count);
>> +
>> +       ret = djrcv_dev->hdev->hid_output_raw_report(djrcv_dev->hdev, out_buf,
>> +               DJREPORT_SHORT_LENGTH, report_type);
>
> Strictly speaking the code below uses HID_REQ_SET_REPORT and you
> replace it with hid_output_raw_report() here (which at least for BTHID
> is not equivalent). Anyhow, HID-core uses hid_output_raw_report(),
> too, so this should be fine.

Yes, you are right. This fires back on me yesterday when I tried to
remove the hid_output_raw_report() calls.
It occurs it works because usbhid_out_raw_report() uses set_report
when there is no urbout, which is the case with logitech receivers.
So I guess an ideal solution would be to implement a hid_hw_request call.

However, the only concern I have with hid_hw_request is that it does
not allow hidraw to play with the LEDs given that hidraw does not have
an ioctl for SET_REPORT (or GET_REPORT). I already seen this issue
regarding i2c_hid at some point, but it was "solved" in i2c_hid by
using the same ugly trick that we have in USB-hid.

Cheers,
Benjamin

>
> Thanks
> David
>
>> +
>> +       kfree(out_buf);
>> +       return ret;
>>  }
>>
>>  static void rdcat(char *rdesc, unsigned int *rsize, const char *data, unsigned int size)
>> @@ -613,58 +637,6 @@ static int logi_dj_ll_parse(struct hid_device *hid)
>>         return retval;
>>  }
>>
>> -static int logi_dj_ll_input_event(struct input_dev *dev, unsigned int type,
>> -                                 unsigned int code, int value)
>> -{
>> -       /* Sent by the input layer to handle leds and Force Feedback */
>> -       struct hid_device *dj_hiddev = input_get_drvdata(dev);
>> -       struct dj_device *dj_dev = dj_hiddev->driver_data;
>> -
>> -       struct dj_receiver_dev *djrcv_dev =
>> -           dev_get_drvdata(dj_hiddev->dev.parent);
>> -       struct hid_device *dj_rcv_hiddev = djrcv_dev->hdev;
>> -       struct hid_report_enum *output_report_enum;
>> -
>> -       struct hid_field *field;
>> -       struct hid_report *report;
>> -       unsigned char *data;
>> -       int offset;
>> -
>> -       dbg_hid("%s: %s, type:%d | code:%d | value:%d\n",
>> -               __func__, dev->phys, type, code, value);
>> -
>> -       if (type != EV_LED)
>> -               return -1;
>> -
>> -       offset = hidinput_find_field(dj_hiddev, type, code, &field);
>> -
>> -       if (offset == -1) {
>> -               dev_warn(&dev->dev, "event field not found\n");
>> -               return -1;
>> -       }
>> -       hid_set_field(field, offset, value);
>> -
>> -       data = hid_alloc_report_buf(field->report, GFP_ATOMIC);
>> -       if (!data) {
>> -               dev_warn(&dev->dev, "failed to allocate report buf memory\n");
>> -               return -1;
>> -       }
>> -
>> -       hid_output_report(field->report, &data[0]);
>> -
>> -       output_report_enum = &dj_rcv_hiddev->report_enum[HID_OUTPUT_REPORT];
>> -       report = output_report_enum->report_id_hash[REPORT_ID_DJ_SHORT];
>> -       hid_set_field(report->field[0], 0, dj_dev->device_index);
>> -       hid_set_field(report->field[0], 1, REPORT_TYPE_LEDS);
>> -       hid_set_field(report->field[0], 2, data[1]);
>> -
>> -       hid_hw_request(dj_rcv_hiddev, report, HID_REQ_SET_REPORT);
>> -
>> -       kfree(data);
>> -
>> -       return 0;
>> -}
>> -
>>  static int logi_dj_ll_start(struct hid_device *hid)
>>  {
>>         dbg_hid("%s\n", __func__);
>> @@ -683,7 +655,6 @@ static struct hid_ll_driver logi_dj_ll_driver = {
>>         .stop = logi_dj_ll_stop,
>>         .open = logi_dj_ll_open,
>>         .close = logi_dj_ll_close,
>> -       .hidinput_input_event = logi_dj_ll_input_event,
>>  };
>>
>>
>> --
>> 1.8.3.1
>>