Re: [PATCH] Input: add touchscreen driver for MELFAS MCS-5000 controller

[Joonyoung Shim <jy0922.shim@samsung.com>]

Hi, sorry for long time no reponse.

>>>> +	case INPUT_TYPE_SINGLE:
>>>> +		x = (buffer[READ_X_POS_UPPER] << 8) | buffer[READ_X_POS_LOWER];
>>>> +		y = (buffer[READ_Y_POS_UPPER] << 8) | buffer[READ_Y_POS_LOWER];
>>>> +
>>>> +		input_report_key(data->input_dev, BTN_TOUCH, 1);
>>>> +		input_report_abs(data->input_dev, ABS_X, x);
>>>> +		input_report_abs(data->input_dev, ABS_Y, y);
>>>> +		input_report_abs(data->input_dev, ABS_PRESSURE,
>>>> +				DEFAULT_PRESSURE);
>>> If the hardware does not support pressure reading don't fake it.
>>> BTN_TOUCH should be enough to signal touch.
>> MCS-5000 supports pressure reading, but the value of pressure is unstable in
>> my target, so i used the static value defined.
>> I will add pressure reading after more test.
> 
> OK. Alternatively you may indicate in the platform data if pressure
> reading is supported and set ABS_PRESSURE bit and report pressure only
> when you know it works well.

This is my mistake, the MCS-5000 does not support pressure. I confused pressure
and proximity.

>>>> +{
>>>> +	struct mcs5000_ts_data *data = i2c_get_clientdata(client);
>>>> +
>>>> +	cancel_work_sync(&data->ts_event_work);
>>> There is a race here, IRQ handler may resubmit work after
>>> cancel_work_sync() returns. You need to  make sure that
>>> IRQ handler does not resubmit work while device is being shut down.
>> ok, how about doing free_irq() before cancel_work_sync() call?
>>
> 
> Then there is a risk that your work will try to enable_irq() on irq that
> was freed. I am not sure if IRQ core will be happy with it,
> 

It is no problem to try to enable_irq() on irq that was freed, but a new
problem is balance of disable_irq() and enable_irq().
I refered drivers/net/phy/phy.c file.

I will post patch v2.

thanks.