Re: [PATCH] elo: Support non-pressure-sensitive ELO touchscreens

From: Dmitry Torokhov
Date: Fri Jul 21 2006 - 02:09:08 EST

On Wednesday 19 July 2006 17:34, Shaun Jackman wrote:
> On 3/28/06, Shaun Jackman <sjackman@xxxxxxxxx> wrote:
> > On 3/27/06, Dmitry Torokhov <dtor_core@xxxxxxxxxxxxx> wrote:
> > ...
> > > No, we should not change basic input device's capabilities "on-fly" -
> > > userspace should be able to rely on what was reported to it in the first
> > > place.
> >
> > Makes sense.
> >
> > > From looking over the documentation (thank you for the link)
> > > it looks like you would need to issue 'i' command to query controller
> > > type and whether the controller supports Z-axis in elo_connect().
> >
> > This sounds like extra (not strictly necessary) functionality to me
> > though. My USB mouse, for example, reports five buttons and three
> > wheels, even though it only has three buttons and one wheel. Support
> > for the 'i' packet could be added later, if someone has a need. Can
> > this patch be applied as is?
>
> Can this patch adding support for non-pressure-sensitive ELO
> touchscreens be applied? Any comments?
>

Shaun,

I still think that we need to query the touchscreen andd act based on
its reported features. Could you please tell me if the patch below works?

Thanks!

--
Dmitry

Subject: elo - add support for non-pressure-sensitive touchscreens
From: Shaun Jackman <sjackman@xxxxxxxxx>

Input: elo - add support for non-pressure-sensitive touchscreens

- Use the touch status bit rather than the pressure bits to
distinguish a BTN_TOUCH event. Non-pressure-sensitive touchscreens
always report full pressure
- Report ABS_PRESSURE information only if the touchscreen supports it
- Implement checksum calculation correctly, and verify that the
transmitted checksum is correct
- Handle input_register_device() failures
- Use dev_dbg to log errors in the protocol

Signed-off-by: Shaun Jackman <sjackman@xxxxxxxxx>
Signed-off-by: Dmitry Torokhov <dtor@xxxxxxx>
---

drivers/input/touchscreen/elo.c | 166 ++++++++++++++++++++++++++++++++--------
1 files changed, 134 insertions(+), 32 deletions(-)

Index: work/drivers/input/touchscreen/elo.c
===================================================================
--- work.orig/drivers/input/touchscreen/elo.c
+++ work/drivers/input/touchscreen/elo.c
@@ -23,6 +23,7 @@
#include <linux/input.h>
#include <linux/serio.h>
#include <linux/init.h>
+#include <linux/ctype.h>

#define DRIVER_DESC "Elo serial touchscreen driver"

@@ -34,7 +35,19 @@ MODULE_LICENSE("GPL");
* Definitions & global arrays.
*/

-#define ELO_MAX_LENGTH 10
+#define ELO_MAX_LENGTH 10
+
+#define ELO10_PACKET_LEN 8
+#define ELO10_TOUCH 0x03
+#define ELO10_PRESSURE 0x80
+
+#define ELO10_LEAD_BYTE 'U'
+
+#define ELO10_ID_CMD 'i'
+
+#define ELO10_TOUCH_PACKET 'T'
+#define ELO10_ACK_PACKET 'A'
+#define ELI10_ID_PACKET 'I'

/*
* Per-touchscreen data.
@@ -43,51 +56,69 @@ MODULE_LICENSE("GPL");
struct elo {
struct input_dev *dev;
struct serio *serio;
+ struct mutex cmd_mutex;
+ struct completion cmd_done;
int id;
int idx;
+ unsigned char expected_packet;
unsigned char csum;
unsigned char data[ELO_MAX_LENGTH];
+ unsigned char response[ELO10_PACKET_LEN];
char phys[32];
};

-static void elo_process_data_10(struct elo* elo, unsigned char data, struct pt_regs *regs)
+static void elo_process_data_10(struct elo *elo, unsigned char data, struct pt_regs *regs)
{
struct input_dev *dev = elo->dev;
+ struct device *dbg = &elo->serio->dev;

- elo->csum += elo->data[elo->idx] = data;
-
+ elo->data[elo->idx] = data;
switch (elo->idx++) {
-
case 0:
- if (data != 'U') {
+ elo->csum = 0xaa;
+ if (data != ELO10_LEAD_BYTE) {
+ dev_dbg(dbg, "unsynchronized data: 0x%02x\n", data);
elo->idx = 0;
- elo->csum = 0;
}
break;
+ case 9:
+ elo->idx = 0;
+ if (elo->csum != elo->data[9]) {
+ dev_dbg(dbg, "bad checksum: 0x%02x, expected 0x%02x\n",
+ elo->data[9], elo->csum);
+ break;
+ }

- case 1:
- if (data != 'T') {
- elo->idx = 0;
- elo->csum = 0;
+ if (elo->data[1] != elo->expected_packet) {
+ if (elo->data[1] != ELO10_TOUCH_PACKET)
+ dev_dbg(dbg, "unexpected packet: 0x%02x\n",
+ elo->data[1]);
+ break;
}
- break;

- case 9:
- if (elo->csum) {
+ if (likely(elo->data[1] == ELO10_TOUCH_PACKET)) {
input_regs(dev, regs);
input_report_abs(dev, ABS_X, (elo->data[4] << 8) | elo->data[3]);
input_report_abs(dev, ABS_Y, (elo->data[6] << 8) | elo->data[5]);
- input_report_abs(dev, ABS_PRESSURE, (elo->data[8] << 8) | elo->data[7]);
- input_report_key(dev, BTN_TOUCH, elo->data[8] || elo->data[7]);
+ if (elo->data[2] & ELO10_PRESSURE)
+ input_report_abs(dev, ABS_PRESSURE,
+ (elo->data[8] << 8) | elo->data[7]);
+ input_report_key(dev, BTN_TOUCH, elo->data[2] & ELO10_TOUCH);
input_sync(dev);
+ } else if (elo->data[1] == ELO10_ACK_PACKET) {
+ if (elo->data[2] == '0')
+ elo->expected_packet = ELO10_TOUCH_PACKET;
+ complete(&elo->cmd_done);
+ } else {
+ memcpy(elo->response, &elo->data[1], ELO10_PACKET_LEN);
+ elo->expected_packet = ELO10_ACK_PACKET;
}
- elo->idx = 0;
- elo->csum = 0;
break;
}
+ elo->csum += data;
}

-static void elo_process_data_6(struct elo* elo, unsigned char data, struct pt_regs *regs)
+static void elo_process_data_6(struct elo *elo, unsigned char data, struct pt_regs *regs)
{
struct input_dev *dev = elo->dev;

@@ -135,7 +166,7 @@ static void elo_process_data_6(struct el
}
}

-static void elo_process_data_3(struct elo* elo, unsigned char data, struct pt_regs *regs)
+static void elo_process_data_3(struct elo *elo, unsigned char data, struct pt_regs *regs)
{
struct input_dev *dev = elo->dev;

@@ -181,17 +212,81 @@ static irqreturn_t elo_interrupt(struct
return IRQ_HANDLED;
}

+static int elo_command_10(struct elo *elo, unsigned char *packet)
+{
+ int rc = -1;
+ int i;
+ unsigned char csum = 0xaa + ELO10_LEAD_BYTE;
+
+ mutex_lock(&elo->cmd_mutex);
+
+ serio_pause_rx(elo->serio);
+ elo->expected_packet = toupper(packet[0]);
+ init_completion(&elo->cmd_done);
+ serio_continue_rx(elo->serio);
+
+ if (serio_write(elo->serio, ELO10_LEAD_BYTE))
+ goto out;
+
+ for (i = 0; i < ELO10_PACKET_LEN; i++) {
+ csum += packet[i];
+ if (serio_write(elo->serio, packet[i]))
+ goto out;
+ }
+
+ if (serio_write(elo->serio, csum))
+ goto out;
+
+ wait_for_completion_timeout(&elo->cmd_done, HZ);
+
+ if (elo->expected_packet == ELO10_TOUCH_PACKET) {
+ /* We are back in reportinG mode, the command was ACKed */
+ memcpy(packet, elo->response, ELO10_PACKET_LEN);
+ rc = 0;
+ }
+
+ out:
+ mutex_unlock(&elo->cmd_mutex);
+ return rc;
+}
+
+static int elo_setup_10(struct elo *elo)
+{
+ static const char *elo_types[] = { "Accu", "Dura", "Intelli", "Carroll" };
+ struct input_dev *dev = elo->dev;
+ unsigned char packet[ELO10_PACKET_LEN] = { ELO10_ID_CMD };
+
+ if (elo_command_10(elo, packet))
+ return -1;
+
+ dev->id.version = (packet[5] << 8) | packet[4];
+
+ input_set_abs_params(dev, ABS_X, 96, 4000, 0, 0);
+ input_set_abs_params(dev, ABS_Y, 96, 4000, 0, 0);
+ if (packet[3] & ELO10_PRESSURE)
+ input_set_abs_params(dev, ABS_PRESSURE, 0, 255, 0, 0);
+
+ printk(KERN_INFO "elo: %sTouch touchscreen, fw: %02x.%02x, "
+ "features: %x02x, controller: 0x%02x\n",
+ elo_types[(packet[1] -'0') & 0x03],
+ packet[5], packet[4], packet[3], packet[7]);
+
+ return 0;
+}
+
/*
* elo_disconnect() is the opposite of elo_connect()
*/

static void elo_disconnect(struct serio *serio)
{
- struct elo* elo = serio_get_drvdata(serio);
+ struct elo *elo = serio_get_drvdata(serio);

+ input_get_device(elo->dev);
input_unregister_device(elo->dev);
serio_close(serio);
serio_set_drvdata(serio, NULL);
+ input_put_device(elo->dev);
kfree(elo);
}

@@ -211,12 +306,15 @@ static int elo_connect(struct serio *ser
input_dev = input_allocate_device();
if (!elo || !input_dev) {
err = -ENOMEM;
- goto fail;
+ goto fail1;
}

elo->serio = serio;
elo->id = serio->id.id;
elo->dev = input_dev;
+ elo->expected_packet = ELO10_TOUCH_PACKET;
+ mutex_init(&elo->cmd_mutex);
+ init_completion(&elo->cmd_done);
snprintf(elo->phys, sizeof(elo->phys), "%s/input0", serio->phys);

input_dev->private = elo;
@@ -231,12 +329,17 @@ static int elo_connect(struct serio *ser
input_dev->evbit[0] = BIT(EV_KEY) | BIT(EV_ABS);
input_dev->keybit[LONG(BTN_TOUCH)] = BIT(BTN_TOUCH);

+ serio_set_drvdata(serio, elo);
+ err = serio_open(serio, drv);
+ if (err)
+ goto fail2;
+
switch (elo->id) {

case 0: /* 10-byte protocol */
- input_set_abs_params(input_dev, ABS_X, 96, 4000, 0, 0);
- input_set_abs_params(input_dev, ABS_Y, 96, 4000, 0, 0);
- input_set_abs_params(input_dev, ABS_PRESSURE, 0, 255, 0, 0);
+ if (elo_setup_10(elo))
+ goto fail3;
+
break;

case 1: /* 6-byte protocol */
@@ -247,23 +350,22 @@ static int elo_connect(struct serio *ser
input_set_abs_params(input_dev, ABS_Y, 96, 4000, 0, 0);
break;

+
case 3: /* 3-byte protocol */
input_set_abs_params(input_dev, ABS_X, 0, 255, 0, 0);
input_set_abs_params(input_dev, ABS_Y, 0, 255, 0, 0);
break;
}

- serio_set_drvdata(serio, elo);
-
- err = serio_open(serio, drv);
+ err = input_register_device(elo->dev);
if (err)
- goto fail;
+ goto fail3;

- input_register_device(elo->dev);
return 0;

- fail: serio_set_drvdata(serio, NULL);
- input_free_device(input_dev);
+ fail3: serio_close(serio);
+ fail2: serio_set_drvdata(serio, NULL);
+ fail1: input_free_device(input_dev);
kfree(elo);
return err;
}
-
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