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

[Henrik Rydberg]

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'.

> +
> +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.

> +			}
>  			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,
Henrik
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