[PATCH 1/3] Input: touchscreen: ad7877 implement specified chip select behavior

[PATCH 1/3] Input: touchscreen: ad7877 implement specified chip select behavior

[michael.hennerich]

From: Michael Hennerich <michael.hennerich@analog.com>

According to the AD7877 datasheet:
Each transfer operation is 16-bit. If multiple read/write operations are
to be performed, CS must be taken high after the end of each read/write
operation before another read/write operation can be performed by
taking CS low again.

Make sure CS toggles after each transfer in the message.

Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
---
 drivers/input/touchscreen/ad7877.c |   12 +++++++++++-
 1 files changed, 11 insertions(+), 1 deletions(-)

diff --git a/drivers/input/touchscreen/ad7877.c b/drivers/input/touchscreen/ad7877.c
index 5f0221c..53f4d79 100644
--- a/drivers/input/touchscreen/ad7877.c
+++ b/drivers/input/touchscreen/ad7877.c
@@ -230,6 +230,7 @@ static int ad7877_read(struct spi_device *spi, u16 reg)
 			AD7877_READADD(reg));
 	req->xfer[0].tx_buf = &req->command;
 	req->xfer[0].len = 2;
+	req->xfer[0].cs_change = 1;
 
 	req->xfer[1].rx_buf = &req->sample;
 	req->xfer[1].len = 2;
@@ -295,20 +296,25 @@ static int ad7877_read_adc(struct spi_device *spi, unsigned command)
 
 	req->xfer[0].tx_buf = &req->reset;
 	req->xfer[0].len = 2;
+	req->xfer[0].cs_change = 1;
 
 	req->xfer[1].tx_buf = &req->ref_on;
 	req->xfer[1].len = 2;
 	req->xfer[1].delay_usecs = ts->vref_delay_usecs;
+	req->xfer[1].cs_change = 1;
 
 	req->xfer[2].tx_buf = &req->command;
 	req->xfer[2].len = 2;
 	req->xfer[2].delay_usecs = ts->vref_delay_usecs;
+	req->xfer[2].cs_change = 1;
 
 	req->xfer[3].rx_buf = &req->sample;
 	req->xfer[3].len = 2;
+	req->xfer[3].cs_change = 1;
 
 	req->xfer[4].tx_buf = &ts->cmd_crtl2;	/*REF OFF*/
 	req->xfer[4].len = 2;
+	req->xfer[4].cs_change = 1;
 
 	req->xfer[5].tx_buf = &ts->cmd_crtl1;	/*DEFAULT*/
 	req->xfer[5].len = 2;
@@ -640,17 +646,21 @@ static void ad7877_setup_ts_def_msg(struct spi_device *spi, struct ad7877 *ts)
 
 	ts->xfer[0].tx_buf = &ts->cmd_crtl1;
 	ts->xfer[0].len = 2;
+	ts->xfer[0].cs_change = 1;
 
 	spi_message_add_tail(&ts->xfer[0], m);
 
 	ts->xfer[1].tx_buf = &ts->cmd_dummy; /* Send ZERO */
 	ts->xfer[1].len = 2;
+	ts->xfer[1].cs_change = 1;
 
 	spi_message_add_tail(&ts->xfer[1], m);
 
-	for (i = 0; i < 11; i++) {
+	for (i = 0; i < AD7877_NR_SENSE; i++) {
 		ts->xfer[i + 2].rx_buf = &ts->conversion_data[AD7877_SEQ_YPOS + i];
 		ts->xfer[i + 2].len = 2;
+		if (i < (AD7877_NR_SENSE - 1))
+			ts->xfer[i + 2].cs_change = 1;
 		spi_message_add_tail(&ts->xfer[i + 2], m);
 	}
 }
-- 
1.6.0.2

[PATCH 2/3] Input: touchscreen: ad7877 implement EV_KEY:BTN_TOUCH reporting

[michael.hennerich]

From: Michael Hennerich <michael.hennerich@analog.com>

Some input users such as Android or X require BTN_TOUCH events.
Implement EV_KEY:BTN_TOUCH and make sure that the release event
is not erroneous scheduled without a preceding valid touch.

Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
---
 drivers/input/touchscreen/ad7877.c |   17 ++++++++++++-----
 1 files changed, 12 insertions(+), 5 deletions(-)

diff --git a/drivers/input/touchscreen/ad7877.c b/drivers/input/touchscreen/ad7877.c
index 53f4d79..96c0a0d 100644
--- a/drivers/input/touchscreen/ad7877.c
+++ b/drivers/input/touchscreen/ad7877.c
@@ -333,7 +333,7 @@ static int ad7877_read_adc(struct spi_device *spi, unsigned command)
 	return status ? : sample;
 }
 
-static void ad7877_rx(struct ad7877 *ts)
+static int ad7877_rx(struct ad7877 *ts)
 {
 	struct input_dev *input_dev = ts->input;
 	unsigned Rt;
@@ -360,11 +360,17 @@ static void ad7877_rx(struct ad7877 *ts)
 		Rt /= z1;
 		Rt = (Rt + 2047) >> 12;
 
+		if (!timer_pending(&ts->timer))
+			input_report_key(input_dev, BTN_TOUCH, 1);
+
 		input_report_abs(input_dev, ABS_X, x);
 		input_report_abs(input_dev, ABS_Y, y);
 		input_report_abs(input_dev, ABS_PRESSURE, Rt);
 		input_sync(input_dev);
+		return 0;
 	}
+
+	return -EINVAL;
 }
 
 static inline void ad7877_ts_event_release(struct ad7877 *ts)
@@ -372,6 +378,7 @@ static inline void ad7877_ts_event_release(struct ad7877 *ts)
 	struct input_dev *input_dev = ts->input;
 
 	input_report_abs(input_dev, ABS_PRESSURE, 0);
+	input_report_key(input_dev, BTN_TOUCH, 0);
 	input_sync(input_dev);
 }
 
@@ -413,11 +420,9 @@ static void ad7877_callback(void *_ts)
 	struct ad7877 *ts = _ts;
 
 	spin_lock_irq(&ts->lock);
-
-	ad7877_rx(ts);
+	if (!ad7877_rx(ts))
+		mod_timer(&ts->timer, jiffies + TS_PEN_UP_TIMEOUT);
 	ts->pending = 0;
-	mod_timer(&ts->timer, jiffies + TS_PEN_UP_TIMEOUT);
-
 	spin_unlock_irq(&ts->lock);
 }
 
@@ -728,6 +733,8 @@ static int __devinit ad7877_probe(struct spi_device *spi)
 	input_dev->phys = ts->phys;
 	input_dev->dev.parent = &spi->dev;
 
+	__set_bit(EV_KEY, input_dev->evbit);
+	__set_bit(BTN_TOUCH, input_dev->keybit);
 	__set_bit(EV_ABS, input_dev->evbit);
 	__set_bit(ABS_X, input_dev->absbit);
 	__set_bit(ABS_Y, input_dev->absbit);
-- 
1.6.0.2

[PATCH 3/3] Input: touchscreen: ad7877 filter events where pressure is beyond the maximum

[michael.hennerich]

From: Michael Hennerich <michael.hennerich@analog.com>

Suppress events where pressure > pressure_max.
These events come typically along with inaccurate X and Y samples.

Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
---
 drivers/input/touchscreen/ad7877.c |    7 +++++++
 1 files changed, 7 insertions(+), 0 deletions(-)

diff --git a/drivers/input/touchscreen/ad7877.c b/drivers/input/touchscreen/ad7877.c
index 96c0a0d..e6917db 100644
--- a/drivers/input/touchscreen/ad7877.c
+++ b/drivers/input/touchscreen/ad7877.c
@@ -360,6 +360,13 @@ static int ad7877_rx(struct ad7877 *ts)
 		Rt /= z1;
 		Rt = (Rt + 2047) >> 12;
 
+		/*
+		 * Sample found inconsistent, pressure is beyond
+		 * the maximum. Don't report it to user space.
+		 */
+	 	if (Rt > ts->pressure_max)
+	 		return -EINVAL;
+
 		if (!timer_pending(&ts->timer))
 			input_report_key(input_dev, BTN_TOUCH, 1);
 
-- 
1.6.0.2

[PATCH 1/3] Input: touchscreen: ad7877 implement specified chip select behavior

[michael.hennerich]

From: Michael Hennerich <michael.hennerich@analog.com>

According to the AD7877 datasheet:
Each transfer operation is 16-bit. If multiple read/write operations are
to be performed, CS must be taken high after the end of each read/write
operation before another read/write operation can be performed by
taking CS low again.

Make sure CS toggles after each transfer in the message.

Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
---
 drivers/input/touchscreen/ad7877.c |   12 +++++++++++-
 1 files changed, 11 insertions(+), 1 deletions(-)

diff --git a/drivers/input/touchscreen/ad7877.c b/drivers/input/touchscreen/ad7877.c
index 5f0221c..53f4d79 100644
--- a/drivers/input/touchscreen/ad7877.c
+++ b/drivers/input/touchscreen/ad7877.c
@@ -230,6 +230,7 @@ static int ad7877_read(struct spi_device *spi, u16 reg)
 			AD7877_READADD(reg));
 	req->xfer[0].tx_buf = &req->command;
 	req->xfer[0].len = 2;
+	req->xfer[0].cs_change = 1;
 
 	req->xfer[1].rx_buf = &req->sample;
 	req->xfer[1].len = 2;
@@ -295,20 +296,25 @@ static int ad7877_read_adc(struct spi_device *spi, unsigned command)
 
 	req->xfer[0].tx_buf = &req->reset;
 	req->xfer[0].len = 2;
+	req->xfer[0].cs_change = 1;
 
 	req->xfer[1].tx_buf = &req->ref_on;
 	req->xfer[1].len = 2;
 	req->xfer[1].delay_usecs = ts->vref_delay_usecs;
+	req->xfer[1].cs_change = 1;
 
 	req->xfer[2].tx_buf = &req->command;
 	req->xfer[2].len = 2;
 	req->xfer[2].delay_usecs = ts->vref_delay_usecs;
+	req->xfer[2].cs_change = 1;
 
 	req->xfer[3].rx_buf = &req->sample;
 	req->xfer[3].len = 2;
+	req->xfer[3].cs_change = 1;
 
 	req->xfer[4].tx_buf = &ts->cmd_crtl2;	/*REF OFF*/
 	req->xfer[4].len = 2;
+	req->xfer[4].cs_change = 1;
 
 	req->xfer[5].tx_buf = &ts->cmd_crtl1;	/*DEFAULT*/
 	req->xfer[5].len = 2;
@@ -640,17 +646,21 @@ static void ad7877_setup_ts_def_msg(struct spi_device *spi, struct ad7877 *ts)
 
 	ts->xfer[0].tx_buf = &ts->cmd_crtl1;
 	ts->xfer[0].len = 2;
+	ts->xfer[0].cs_change = 1;
 
 	spi_message_add_tail(&ts->xfer[0], m);
 
 	ts->xfer[1].tx_buf = &ts->cmd_dummy; /* Send ZERO */
 	ts->xfer[1].len = 2;
+	ts->xfer[1].cs_change = 1;
 
 	spi_message_add_tail(&ts->xfer[1], m);
 
-	for (i = 0; i < 11; i++) {
+	for (i = 0; i < AD7877_NR_SENSE; i++) {
 		ts->xfer[i + 2].rx_buf = &ts->conversion_data[AD7877_SEQ_YPOS + i];
 		ts->xfer[i + 2].len = 2;
+		if (i < (AD7877_NR_SENSE - 1))
+			ts->xfer[i + 2].cs_change = 1;
 		spi_message_add_tail(&ts->xfer[i + 2], m);
 	}
 }
-- 
1.6.0.2

[PATCH 2/3] Input: touchscreen: ad7877 implement EV_KEY:BTN_TOUCH reporting

[michael.hennerich]

From: Michael Hennerich <michael.hennerich@analog.com>

Some input users such as Android or X require BTN_TOUCH events.
Implement EV_KEY:BTN_TOUCH and make sure that the release event
is not erroneous scheduled without a preceding valid touch.

Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
---
 drivers/input/touchscreen/ad7877.c |   17 ++++++++++++-----
 1 files changed, 12 insertions(+), 5 deletions(-)

diff --git a/drivers/input/touchscreen/ad7877.c b/drivers/input/touchscreen/ad7877.c
index 53f4d79..96c0a0d 100644
--- a/drivers/input/touchscreen/ad7877.c
+++ b/drivers/input/touchscreen/ad7877.c
@@ -333,7 +333,7 @@ static int ad7877_read_adc(struct spi_device *spi, unsigned command)
 	return status ? : sample;
 }
 
-static void ad7877_rx(struct ad7877 *ts)
+static int ad7877_rx(struct ad7877 *ts)
 {
 	struct input_dev *input_dev = ts->input;
 	unsigned Rt;
@@ -360,11 +360,17 @@ static void ad7877_rx(struct ad7877 *ts)
 		Rt /= z1;
 		Rt = (Rt + 2047) >> 12;
 
+		if (!timer_pending(&ts->timer))
+			input_report_key(input_dev, BTN_TOUCH, 1);
+
 		input_report_abs(input_dev, ABS_X, x);
 		input_report_abs(input_dev, ABS_Y, y);
 		input_report_abs(input_dev, ABS_PRESSURE, Rt);
 		input_sync(input_dev);
+		return 0;
 	}
+
+	return -EINVAL;
 }
 
 static inline void ad7877_ts_event_release(struct ad7877 *ts)
@@ -372,6 +378,7 @@ static inline void ad7877_ts_event_release(struct ad7877 *ts)
 	struct input_dev *input_dev = ts->input;
 
 	input_report_abs(input_dev, ABS_PRESSURE, 0);
+	input_report_key(input_dev, BTN_TOUCH, 0);
 	input_sync(input_dev);
 }
 
@@ -413,11 +420,9 @@ static void ad7877_callback(void *_ts)
 	struct ad7877 *ts = _ts;
 
 	spin_lock_irq(&ts->lock);
-
-	ad7877_rx(ts);
+	if (!ad7877_rx(ts))
+		mod_timer(&ts->timer, jiffies + TS_PEN_UP_TIMEOUT);
 	ts->pending = 0;
-	mod_timer(&ts->timer, jiffies + TS_PEN_UP_TIMEOUT);
-
 	spin_unlock_irq(&ts->lock);
 }
 
@@ -728,6 +733,8 @@ static int __devinit ad7877_probe(struct spi_device *spi)
 	input_dev->phys = ts->phys;
 	input_dev->dev.parent = &spi->dev;
 
+	__set_bit(EV_KEY, input_dev->evbit);
+	__set_bit(BTN_TOUCH, input_dev->keybit);
 	__set_bit(EV_ABS, input_dev->evbit);
 	__set_bit(ABS_X, input_dev->absbit);
 	__set_bit(ABS_Y, input_dev->absbit);
-- 
1.6.0.2