Re: [PATCH v10 52/55] input: touchscreen: atmel_mxt_ts: Added sysfs entry for touchscreen status

From: Dmitry Osipenko
Date: Tue Mar 31 2020 - 11:08:55 EST


31.03.2020 13:50, Jiada Wang ÐÐÑÐÑ:
...
> +static void mxt_watchdog_work(struct work_struct *work)
> +{
> + struct mxt_data *data =
> + container_of(work, struct mxt_data, watchdog_work.work);
> + u16 info_buf;
> + int ret;
> +
> + if (data->suspended || data->in_bootloader ||
> + data->mxt_status.intp_triggered)
> + goto sched_work;

Won't it become a problem if other thread puts device into suspended /
bootloader state in the same time?

> + ret = __mxt_read_reg(data->client, 0, sizeof(info_buf), &info_buf);
> +
> + if (ret) {
> + data->mxt_status.error_count++;
> + data->mxt_status.dev_status = false;
> + } else {
> + data->mxt_status.dev_status = true;
> + }
> +
> +sched_work:
> + schedule_delayed_work(&data->watchdog_work,
> + msecs_to_jiffies(MXT_WATCHDOG_TIMEOUT));
> +}
...

> @@ -4329,6 +4390,12 @@ static int mxt_probe(struct i2c_client *client, const struct i2c_device_id *id)
> msleep(MXT_RESET_TIME);
> }
>
> + if (debug_state) {
> + INIT_DELAYED_WORK(&data->watchdog_work, mxt_watchdog_work);
> + schedule_delayed_work(&data->watchdog_work,
> + msecs_to_jiffies(MXT_WATCHDOG_TIMEOUT));
> + }
> +
> error = mxt_initialize(data);
> if (error)
> goto err_free_object;
> @@ -4343,6 +4410,8 @@ static int mxt_probe(struct i2c_client *client, const struct i2c_device_id *id)
> return 0;
>
> err_free_object:
> + if (debug_state)
> + cancel_delayed_work_sync(&data->watchdog_work);
> mxt_free_input_device(data);
> mxt_free_object_table(data);
> if (data->reset_gpio) {
> @@ -4367,6 +4436,9 @@ static int mxt_remove(struct i2c_client *client)
> mxt_free_input_device(data);
> mxt_free_object_table(data);
>
> + if (debug_state)
> + cancel_delayed_work_sync(&data->watchdog_work);

What will happen if debug_state was false during of mxt_probe() and then
the debug_state parameter was changed to true via sysfs?

I think the INIT_DELAYED_WORK() and cancel_delayed_work_sync() should be
invoked unconditionally.

> return 0;
> }
>
> @@ -4463,3 +4535,7 @@ module_i2c_driver(mxt_driver);
> MODULE_AUTHOR("Joonyoung Shim <jy0922.shim@xxxxxxxxxxx>");
> MODULE_DESCRIPTION("Atmel maXTouch Touchscreen driver");
> MODULE_LICENSE("GPL");
> +
> +module_param(debug_state, bool, 0);
> +MODULE_PARM_DESC(debug_state, "Enable/Disable watchdog work to check device state (default="
> + __MODULE_STRING(MXT_DEBUG_STATE) ")");
>

The "default=..." part of MODULE_PARM_DESC() probably isn't really
useful and could be omitted, don't you think so?