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SubjectRe: [PATCH v7 03/48] Input: atmel_mxt_ts - only read messages in mxt_acquire_irq() when necessary
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12.02.2020 11:41, Jiada Wang пишет:
> From: Nick Dyer <nick.dyer@itdev.co.uk>
>
> 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.

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