Re: [PATCH v5 4/7] Input: pixcir_i2c_ts: Use Type-B Multi-Touch protocol

[Roger Quadros]

Hi Henrik,

On 05/19/2014 10:04 AM, Henrik Rydberg wrote:
> Hi Roger,
> 
> Thanks for the patch series. I think the patch looks great in general. Please
> see some minor comments below.
> 
> On 05/06/2014 01:06 PM, Roger Quadros wrote:
>> Switch to using the Type-B Multi-Touch protocol.
>>
>> Signed-off-by: Roger Quadros <rogerq@xxxxxx>
>> ---
>>  drivers/input/touchscreen/pixcir_i2c_ts.c | 125 ++++++++++++++++++++++--------
>>  1 file changed, 94 insertions(+), 31 deletions(-)
>>
>> diff --git a/drivers/input/touchscreen/pixcir_i2c_ts.c b/drivers/input/touchscreen/pixcir_i2c_ts.c
>> index 8a7da61..1b6e4e5 100644
>> --- a/drivers/input/touchscreen/pixcir_i2c_ts.c
>> +++ b/drivers/input/touchscreen/pixcir_i2c_ts.c
>> @@ -23,9 +23,12 @@
>>  #include <linux/slab.h>
>>  #include <linux/i2c.h>
>>  #include <linux/input.h>
>> +#include <linux/input/mt.h>
>>  #include <linux/input/pixcir_ts.h>
>>  #include <linux/gpio.h>
>>  
>> +#define PIXCIR_MAX_SLOTS       2
>> +
>>  struct pixcir_i2c_ts_data {
>>  	struct i2c_client *client;
>>  	struct input_dev *input;
>> @@ -33,12 +36,25 @@ struct pixcir_i2c_ts_data {
>>  	bool running;
>>  };
>>  
>> -static void pixcir_ts_poscheck(struct pixcir_i2c_ts_data *data)
>> +struct pixcir_touch {
>> +	int x;
>> +	int y;
>> +};
>> +
>> +struct pixcir_report_data {
>> +	int num_touches;
>> +	struct pixcir_touch touches[PIXCIR_MAX_SLOTS];
>> +};
>> +
>> +static void pixcir_ts_parse(struct pixcir_i2c_ts_data *tsdata,
>> +			    struct pixcir_report_data *report)
>>  {
>> -	struct pixcir_i2c_ts_data *tsdata = data;
>>  	u8 rdbuf[10], wrbuf[1] = { 0 };
>> +	u8 *bufptr;
>>  	u8 touch;
>> -	int ret;
>> +	int ret, i;
>> +
>> +	memset(report, 0, sizeof(struct pixcir_report_data));
>>  
>>  	ret = i2c_master_send(tsdata->client, wrbuf, sizeof(wrbuf));
>>  	if (ret != sizeof(wrbuf)) {
>> @@ -56,45 +72,85 @@ static void pixcir_ts_poscheck(struct pixcir_i2c_ts_data *data)
>>  		return;
>>  	}
>>  
>> -	touch = rdbuf[0];
>> -	if (touch) {
>> -		u16 posx1 = (rdbuf[3] << 8) | rdbuf[2];
>> -		u16 posy1 = (rdbuf[5] << 8) | rdbuf[4];
>> -		u16 posx2 = (rdbuf[7] << 8) | rdbuf[6];
>> -		u16 posy2 = (rdbuf[9] << 8) | rdbuf[8];
>> -
>> -		input_report_key(tsdata->input, BTN_TOUCH, 1);
>> -		input_report_abs(tsdata->input, ABS_X, posx1);
>> -		input_report_abs(tsdata->input, ABS_Y, posy1);
>> -
>> -		input_report_abs(tsdata->input, ABS_MT_POSITION_X, posx1);
>> -		input_report_abs(tsdata->input, ABS_MT_POSITION_Y, posy1);
>> -		input_mt_sync(tsdata->input);
>> -
>> -		if (touch == 2) {
>> -			input_report_abs(tsdata->input,
>> -					 ABS_MT_POSITION_X, posx2);
>> -			input_report_abs(tsdata->input,
>> -					 ABS_MT_POSITION_Y, posy2);
>> -			input_mt_sync(tsdata->input);
>> -		}
>> -	} else {
>> -		input_report_key(tsdata->input, BTN_TOUCH, 0);
>> +	touch = rdbuf[0] & 0x7;
>> +	if (touch > PIXCIR_MAX_SLOTS)
>> +		touch = PIXCIR_MAX_SLOTS;
>> +
>> +	report->num_touches = touch;
>> +	bufptr = &rdbuf[2];
>> +
>> +	for (i = 0; i < touch; i++) {
>> +		report->touches[i].x = (bufptr[1] << 8) | bufptr[0];
>> +		report->touches[i].y = (bufptr[3] << 8) | bufptr[2];
>> +
>> +		bufptr = &bufptr[4];
>>  	}
>> +}
> 
> In many places, the '&ptr[index]' form makes a lot of sense, but here, it would
> have been clearer to use 'bufptr += 4'.

Agreed. I'll update it.

> 
>> +
>> +static void pixcir_ts_report(struct pixcir_i2c_ts_data *ts,
>> +			     struct pixcir_report_data *report)
>> +{
>> +	struct input_mt_pos pos[PIXCIR_MAX_SLOTS];
>> +	int slots[PIXCIR_MAX_SLOTS];
>> +	struct pixcir_touch *touch;
>> +	int n, i, slot;
>> +	struct device *dev = &ts->client->dev;
>>  
>> -	input_sync(tsdata->input);
>> +	n = report->num_touches;
>> +	if (n > PIXCIR_MAX_SLOTS)
>> +		n = PIXCIR_MAX_SLOTS;
>> +
>> +	for (i = 0; i < n; i++) {
>> +		touch = &report->touches[i];
>> +		pos[i].x = touch->x;
>> +		pos[i].y = touch->y;
>> +	}
>> +
>> +	input_mt_assign_slots(ts->input, slots, pos, n);
>> +
>> +	for (i = 0; i < n; i++) {
>> +		touch = &report->touches[i];
>> +		slot = slots[i];
>> +
>> +		input_mt_slot(ts->input, slot);
>> +		input_mt_report_slot_state(ts->input,
>> +					   MT_TOOL_FINGER, true);
>> +
>> +		input_event(ts->input, EV_ABS, ABS_MT_POSITION_X, touch->x);
>> +		input_event(ts->input, EV_ABS, ABS_MT_POSITION_Y, touch->y);
>> +
>> +		dev_dbg(dev, "%d: slot %d, x %d, y %d\n",
>> +			i, slot, touch->x, touch->y);
>> +	}
>> +
>> +	input_mt_sync_frame(ts->input);
>> +	input_sync(ts->input);
>>  }
>>  
>>  static irqreturn_t pixcir_ts_isr(int irq, void *dev_id)
>>  {
>>  	struct pixcir_i2c_ts_data *tsdata = dev_id;
>>  	const struct pixcir_ts_platform_data *pdata = tsdata->chip;
>> +	struct pixcir_report_data report;
>>  
>>  	while (tsdata->running) {
>> -		pixcir_ts_poscheck(tsdata);
>> -
>> -		if (gpio_get_value(pdata->gpio_attb))
>> +		/* parse packet */
>> +		pixcir_ts_parse(tsdata, &report);
>> +
>> +		/* report it */
>> +		pixcir_ts_report(tsdata, &report);
>> +
>> +		if (gpio_get_value(pdata->gpio_attb)) {
>> +			if (report.num_touches) {
>> +				/*
>> +				 * Last report with no finger up?
>> +				 * Do it now then.
>> +				 */
>> +				input_mt_sync_frame(tsdata->input);
>> +				input_sync(tsdata->input);
> 
> I think this construct is alright for this particular patch. If anything, it
> points at a need for a better model of interrupted contacts in the core.

OK. 

> 
>> +			}
>>  			break;
>> +		}
>>  
>>  		msleep(20);
>>  	}
>> @@ -333,6 +389,13 @@ static int pixcir_i2c_ts_probe(struct i2c_client *client,
>>  	input_set_abs_params(input, ABS_MT_POSITION_X, 0, pdata->x_max, 0, 0);
>>  	input_set_abs_params(input, ABS_MT_POSITION_Y, 0, pdata->y_max, 0, 0);
>>  
>> +	error = input_mt_init_slots(input, PIXCIR_MAX_SLOTS,
>> +				    INPUT_MT_DIRECT | INPUT_MT_DROP_UNUSED);
>> +	if (error) {
>> +		dev_err(dev, "Error initializing Multi-Touch slots\n");
>> +		return error;
>> +	}
>> +
>>  	input_set_drvdata(input, tsdata);
>>  
>>  	error = devm_gpio_request_one(dev, pdata->gpio_attb,
>>
> 
>     Reviewed-by: Henrik Rydberg <rydberg@xxxxxxxxxxx>

Thanks for the review.

cheers,
-roger

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