[1/7] HID: i2c-hid: Fold i2c_hid_execute_reset() into i2c_hid_hwreset()

i2c_hid_hwreset() is the only caller of i2c_hid_execute_reset(),
fold the latter into the former.

This is a preparation patch for removing the need for
I2C_HID_QUIRK_NO_IRQ_AFTER_RESET by making i2c-hid behave
more like Windows.

No functional changes intended.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
---
 drivers/hid/i2c-hid/i2c-hid-core.c | 80 +++++++++++++-----------------
 1 file changed, 34 insertions(+), 46 deletions(-)

Hi,

On Sat, Nov 4, 2023 at 4:17 AM Hans de Goede <hdegoede@redhat.com> wrote:
>
> @@ -482,21 +442,49 @@ static int i2c_hid_hwreset(struct i2c_hid *ihid)
>
>         ret = i2c_hid_set_power(ihid, I2C_HID_PWR_ON);
>         if (ret)
> -               goto out_unlock;
> +               goto err_unlock;
>
> -       ret = i2c_hid_execute_reset(ihid);
> +       /* Prepare reset command. Command register goes first. */
> +       *(__le16 *)ihid->cmdbuf = ihid->hdesc.wCommandRegister;
> +       length += sizeof(__le16);
> +       /* Next is RESET command itself */
> +       length += i2c_hid_encode_command(ihid->cmdbuf + length,
> +                                        I2C_HID_OPCODE_RESET, 0, 0);
> +
> +       set_bit(I2C_HID_RESET_PENDING, &ihid->flags);
> +
> +       ret = i2c_hid_xfer(ihid, ihid->cmdbuf, length, NULL, 0);
>         if (ret) {
>                 dev_err(&ihid->client->dev,
>                         "failed to reset device: %d\n", ret);
> -               i2c_hid_set_power(ihid, I2C_HID_PWR_SLEEP);
> -               goto out_unlock;
> +               goto err_clear_reset;
>         }
>
> +       if (ihid->quirks & I2C_HID_QUIRK_NO_IRQ_AFTER_RESET) {
> +               msleep(100);
> +               clear_bit(I2C_HID_RESET_PENDING, &ihid->flags);
> +       }
> +
> +       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;
> +               goto err_clear_reset;
> +       }
> +       i2c_hid_dbg(ihid, "%s: finished.\n", __func__);

super nitty, but I wonder if your i2c_hid_dbg() message saying
"waiting" should move above the check for
I2C_HID_QUIRK_NO_IRQ_AFTER_RESET. Then you'll have a message printed
before your msleep. I guess technically you could then add an "else
if" for the second "if" statement which would make it more obvious to
the reader that the "wait_event_timeout" won't happen when the quirk
is present.

Above is just a nit, so:

Reviewed-by: Douglas Anderson <dianders@chromium.org>

Hi Douglas,

Thank you for the reviews.

On 11/6/23 19:50, Doug Anderson wrote:
> Hi,
> 
> On Sat, Nov 4, 2023 at 4:17 AM Hans de Goede <hdegoede@redhat.com> wrote:
>>
>> @@ -482,21 +442,49 @@ static int i2c_hid_hwreset(struct i2c_hid *ihid)
>>
>>         ret = i2c_hid_set_power(ihid, I2C_HID_PWR_ON);
>>         if (ret)
>> -               goto out_unlock;
>> +               goto err_unlock;
>>
>> -       ret = i2c_hid_execute_reset(ihid);
>> +       /* Prepare reset command. Command register goes first. */
>> +       *(__le16 *)ihid->cmdbuf = ihid->hdesc.wCommandRegister;
>> +       length += sizeof(__le16);
>> +       /* Next is RESET command itself */
>> +       length += i2c_hid_encode_command(ihid->cmdbuf + length,
>> +                                        I2C_HID_OPCODE_RESET, 0, 0);
>> +
>> +       set_bit(I2C_HID_RESET_PENDING, &ihid->flags);
>> +
>> +       ret = i2c_hid_xfer(ihid, ihid->cmdbuf, length, NULL, 0);
>>         if (ret) {
>>                 dev_err(&ihid->client->dev,
>>                         "failed to reset device: %d\n", ret);
>> -               i2c_hid_set_power(ihid, I2C_HID_PWR_SLEEP);
>> -               goto out_unlock;
>> +               goto err_clear_reset;
>>         }
>>
>> +       if (ihid->quirks & I2C_HID_QUIRK_NO_IRQ_AFTER_RESET) {
>> +               msleep(100);
>> +               clear_bit(I2C_HID_RESET_PENDING, &ihid->flags);
>> +       }
>> +
>> +       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;
>> +               goto err_clear_reset;
>> +       }
>> +       i2c_hid_dbg(ihid, "%s: finished.\n", __func__);
> 
> super nitty, but I wonder if your i2c_hid_dbg() message saying
> "waiting" should move above the check for
> I2C_HID_QUIRK_NO_IRQ_AFTER_RESET. Then you'll have a message printed
> before your msleep. I guess technically you could then add an "else
> if" for the second "if" statement which would make it more obvious to
> the reader that the "wait_event_timeout" won't happen when the quirk
> is present.
> 
> Above is just a nit

I agree with you that it would be better to move the
mutex_[un]lock(&ihid->reset_lock) calls out of
i2c_hid_start_hwreset() / i2c_hid_finish_hwreset() and into their
callers. I'm preparing a v2 with these changes now and I'll also
move the

       i2c_hid_dbg(ihid, "%s: waiting...\n", __func__);

line to above the I2C_HID_QUIRK_NO_IRQ_AFTER_RESET test for v2.

Regards,

Hans