Re: [PATCH v7 03/48] Input: atmel_mxt_ts - only read messages in mxt_acquire_irq() when necessary

[Wang, Jiada]

Hello Dmitry

On 2020/03/18 7:44, Dmitry Osipenko wrote:
> 12.02.2020 11:41, Jiada Wang ÐÐÑÐÑ:
> > From: Nick Dyer <nick.dyer@xxxxxxxxxxx>
> >
> > The workaround of reading all messages until an invalid is received is a
> > way of forcing the CHG line high, which means that when using
> > edge-triggered interrupts the interrupt can be acquired.
> >
> > With level-triggered interrupts the workaround is unnecessary.
> >
> > Also, most recent maXTouch chips have a feature called RETRIGEN which, when
> > enabled, reasserts the interrupt line every cycle if there are messages
> > waiting. This also makes the workaround unnecessary.
> >
> > Note: the RETRIGEN feature is only in some firmware versions/chips, it's
> > not valid simply to enable the bit.
>
> ...
> > +static int mxt_check_retrigen(struct mxt_data *data)
> > +{
> > +	struct i2c_client *client = data->client;
> > +	int error;
> > +	int val;
> > +
> > +	data->use_retrigen_workaround = false;
> > +
> > +	if (irq_get_trigger_type(data->irq) & IRQF_TRIGGER_LOW)
> > +		return 0;
> > +
> > +	if (data->T18_address) {
> > +		error = __mxt_read_reg(client,
> > +				       data->T18_address + MXT_COMMS_CTRL,
> > +				       1, &val);
> > +		if (error)
> > +			return error;
> > +
> > +		if (val & MXT_COMMS_RETRIGEN)
> > +			return 0;
> > +	}
> > +
> > +	dev_warn(&client->dev, "Enabling RETRIGEN workaround\n");
> > +	data->use_retrigen_workaround = true;
> > +	return 0;
> > +}
>
> Hello Jiada,
>
> I'm seeing "Enabling RETRIGEN workaround" message with the following
> device-tree entry:
>
> touchscreen@4c {
> 	compatible = "atmel,maxtouch";
> 	reg = <0x4c>;
>
> 	interrupt-parent = <&gpio>;
> 	interrupts = <TEGRA_GPIO(V, 6) IRQ_TYPE_LEVEL_LOW>;
>
> 	reset-gpios = <&gpio TEGRA_GPIO(Q, 7) GPIO_ACTIVE_HIGH>;
> };
>
> This happens because data->irq is NULL. Please fix it, thanks in advance.
Thanks for reporting this issue,
I will fix this issue in v8 patch-set

Thanks,
Jiada
>