On Jul 11 2014 or thereabouts, Andrew Duggan wrote:
> Currently, the i2c-hid driver does not call the suspend, resume, and
> reset_resume callbacks in the hid_driver struct when those events occur.
> This means that HID drivers for i2c-hid devices will not be able to execute
> commands which may be needed during suspend or resume. One example is when a
> touchpad using the hid-multitouch driver gets reset by i2c-hid coming out of
> resume. Since the reset_resume callback never gets called the device is never
> put back into the correct input mode. This patch calls the suspend and resume
> callbacks and tries to duplicate the functionality of the usb-hid driver.
>
> Signed-off-by: Andrew Duggan <aduggan@xxxxxxxxxxxxx>
> Signed-off-by: Vincent Huang <vincent.huang@xxxxxxxxxxxxxxxx>
> ---
> Hi Benjamin,
>
> This is the patch which Vincent and I came up with to fix the behavior which we were seeing with touchpads not being operational after resuming. We only use the reset_resume callback since i2c_hid_resume is always doing a hardware reset and it doesn't seem like there is a condition in which the standard resume callback would be appropriate. Also, is a full hardware reset always needed when resuming?
Hi Andrew,
well, the PM management of i2c_hid has been handled by Mika (in CC) and
I am unfortunately not able to have a strong opinion on this. I still
lack of hardware properly supporting the suspend/resume mechanism.
So, you are in charge of that. IIRC, nothing prevents from not calling
hw_reset, but I guess this was the safer implementation we could have.
Anyway, the patch looks good:
Reviewed-by: Benjamin Tissoires <benjamin.tissoires@xxxxxxxxxx>
Cheers,
Benjamin
>
> drivers/hid/i2c-hid/i2c-hid.c | 15 ++++++++++++++-
> 1 file changed, 14 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/hid/i2c-hid/i2c-hid.c b/drivers/hid/i2c-hid/i2c-hid.c
> index 21aafc8..747d544 100644
> --- a/drivers/hid/i2c-hid/i2c-hid.c
> +++ b/drivers/hid/i2c-hid/i2c-hid.c
> @@ -1054,21 +1054,29 @@ static int i2c_hid_remove(struct i2c_client *client)
> static int i2c_hid_suspend(struct device *dev)
> {
> struct i2c_client *client = to_i2c_client(dev);
> + struct i2c_hid *ihid = i2c_get_clientdata(client);
> + struct hid_device *hid = ihid->hid;
> + int ret = 0;
>
> disable_irq(client->irq);
> if (device_may_wakeup(&client->dev))
> enable_irq_wake(client->irq);
>
> + if (hid->driver && hid->driver->suspend)
> + ret = hid->driver->suspend(hid, PMSG_SUSPEND);
> +
> /* Save some power */
> i2c_hid_set_power(client, I2C_HID_PWR_SLEEP);
>
> - return 0;
> + return ret;
> }
>
> static int i2c_hid_resume(struct device *dev)
> {
> int ret;
> struct i2c_client *client = to_i2c_client(dev);
> + struct i2c_hid *ihid = i2c_get_clientdata(client);
> + struct hid_device *hid = ihid->hid;
>
> enable_irq(client->irq);
> ret = i2c_hid_hwreset(client);
> @@ -1078,6 +1086,11 @@ static int i2c_hid_resume(struct device *dev)
> if (device_may_wakeup(&client->dev))
> disable_irq_wake(client->irq);
>
> + if (hid->driver && hid->driver->reset_resume) {
> + ret = hid->driver->reset_resume(hid);
> + return ret;
> + }
> +
> return 0;
> }
> #endif
> --
> 1.9.1
>
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