[v2,4/8] Input: pixcir_i2c_ts: Use Type-B Multi-Touch protocol

Message ID 1393428486-15001-5-git-send-email-rogerq@ti.com
State New
Headers show

Commit Message

Roger Quadros Feb. 26, 2014, 3:28 p.m.
Switch to using the Type-B Multi-Touch protocol.

Signed-off-by: Roger Quadros <rogerq@ti.com>
---
 drivers/input/touchscreen/pixcir_i2c_ts.c | 125 ++++++++++++++++++++++--------
 1 file changed, 94 insertions(+), 31 deletions(-)

Comments

Henrik Rydberg March 8, 2014, 3:11 p.m. | #1
Hi Roger,

the MT implementation seems mostly fine, just one curiosity:

>  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->exiting) {
> -		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);

Why is this special handling needed?

Thanks,
Henrik

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Roger Quadros March 10, 2014, 8:57 a.m. | #2
Hi Henrik,

On 03/08/2014 05:11 PM, Henrik Rydberg wrote:
> Hi Roger,
> 
> the MT implementation seems mostly fine, just one curiosity:
> 
>>  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->exiting) {
>> -		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);
> 
> Why is this special handling needed?

This is needed because the controller doesn't always report when all fingers
have left the screen. e.g. report might contain 3 fingers touched and then
gpio_attb line is de-asserted. There's no report with 0 fingers touched even
if the user's fingers have left the screen. So we never detect a BUTTON_UP.

Without this s/w workaround we observe side effects like buttons being pressed
but not released. To me it looks like a bug in the controller.

cheers,
-roger
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Felipe Balbi March 10, 2014, 4:37 p.m. | #3
On Mon, Mar 10, 2014 at 10:57:10AM +0200, Roger Quadros wrote:
> Hi Henrik,
> 
> On 03/08/2014 05:11 PM, Henrik Rydberg wrote:
> > Hi Roger,
> > 
> > the MT implementation seems mostly fine, just one curiosity:
> > 
> >>  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->exiting) {
> >> -		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);
> > 
> > Why is this special handling needed?
> 
> This is needed because the controller doesn't always report when all fingers
> have left the screen. e.g. report might contain 3 fingers touched and then
> gpio_attb line is de-asserted. There's no report with 0 fingers touched even
> if the user's fingers have left the screen. So we never detect a BUTTON_UP.
> 
> Without this s/w workaround we observe side effects like buttons being pressed
> but not released. To me it looks like a bug in the controller.

the other way would be to *also* use IRQF_TRIGGER_RISING, then you get
an IRQ when fingers leave the screen. No ?
Roger Quadros March 11, 2014, 9:35 a.m. | #4
On 03/10/2014 06:37 PM, Felipe Balbi wrote:
> On Mon, Mar 10, 2014 at 10:57:10AM +0200, Roger Quadros wrote:
>> Hi Henrik,
>>
>> On 03/08/2014 05:11 PM, Henrik Rydberg wrote:
>>> Hi Roger,
>>>
>>> the MT implementation seems mostly fine, just one curiosity:
>>>
>>>>  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->exiting) {
>>>> -		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);
>>>
>>> Why is this special handling needed?
>>
>> This is needed because the controller doesn't always report when all fingers
>> have left the screen. e.g. report might contain 3 fingers touched and then
>> gpio_attb line is de-asserted. There's no report with 0 fingers touched even
>> if the user's fingers have left the screen. So we never detect a BUTTON_UP.
>>
>> Without this s/w workaround we observe side effects like buttons being pressed
>> but not released. To me it looks like a bug in the controller.
> 
> the other way would be to *also* use IRQF_TRIGGER_RISING, then you get
> an IRQ when fingers leave the screen. No ?
> 

Yes that is also possible but it involves an additional interrupt context switch.
Sometimes the controller does report 0 finger touches before de-asserting the ATTB line and so
this additional interrupt is not needed by the approach I used.

cheers,
-roger
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Roger Quadros March 19, 2014, 11:27 a.m. | #5
Henrik,

On 03/10/2014 06:37 PM, Felipe Balbi wrote:
> On Mon, Mar 10, 2014 at 10:57:10AM +0200, Roger Quadros wrote:
>> Hi Henrik,
>>
>> On 03/08/2014 05:11 PM, Henrik Rydberg wrote:
>>> Hi Roger,
>>>
>>> the MT implementation seems mostly fine, just one curiosity:
>>>
>>>>  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->exiting) {
>>>> -		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);
>>>
>>> Why is this special handling needed?
>>
>> This is needed because the controller doesn't always report when all fingers
>> have left the screen. e.g. report might contain 3 fingers touched and then
>> gpio_attb line is de-asserted. There's no report with 0 fingers touched even
>> if the user's fingers have left the screen. So we never detect a BUTTON_UP.
>>
>> Without this s/w workaround we observe side effects like buttons being pressed
>> but not released. To me it looks like a bug in the controller.
> 
> the other way would be to *also* use IRQF_TRIGGER_RISING, then you get
> an IRQ when fingers leave the screen. No ?
> 

If you are OK with my explanation and the patches, could you please Ack them? Thanks.

cheers,
-roger
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Patch

diff --git a/drivers/input/touchscreen/pixcir_i2c_ts.c b/drivers/input/touchscreen/pixcir_i2c_ts.c
index fe17b41..8736f71 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 exiting;
 };
 
-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];
 	}
+}
+
+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->exiting) {
-		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);
+			}
 			break;
+		}
 
 		msleep(20);
 	}
@@ -330,6 +386,13 @@  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,