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Re: [Gumstix-users] Palo touch and Tobi interference issues
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From: Elvis D. <elv...@ma...> - 2009-05-17 00:28:38
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Hi,
On May 17, 2009, at 3:57 AM, David Vescovi wrote:
>
> Still wondering if the SPI input is an existing issue.
> Anyone have the touch screen working?
I've got the Samsung touchscreen working. I've had to modify the
ADS7846 controller files as follows to improve the touchscreen
response. Here is a patch file for the modifications to get a lighter
response from the touchscreen.
Best regards,
Elvis
diff --git a/arch/arm/mach-omap2/board-overo.c b/arch/arm/mach-omap2/
board-overo.c
index ea0f695..ad2094e 100644
--- a/arch/arm/mach-omap2/board-overo.c
+++ b/arch/arm/mach-omap2/board-overo.c
@@ -138,11 +138,17 @@ static int ads7846_get_pendown_state(void)
static struct ads7846_platform_data ads7846_config = {
.x_max = 0x0fff,
.y_max = 0x0fff,
- .x_plate_ohms = 180,
+#if defined(CONFIG_PANEL_SAMSUNG_LTE430WQ_F0C)
+ .x_plate_ohms = CONFIG_PANEL_SAMSUNG_LTE430WQ_FOC_RESISTANCE_X_PLATE,
+ .y_plate_ohms =
CONFIG_PANEL_SAMSUNG_LTE430WQ_FOC_RESISTANCE_Y_PLATE,
+#else
+ .x_plate_ohms = 180,
+ .y_plate_ohms = 180,
+#endif
.pressure_max = 255,
- .debounce_max = 10,
- .debounce_tol = 3,
- .debounce_rep = 1,
+ .debounce_max = CONFIG_TOUCHSCREEN_ADS7846_FILTER_DEBOUNCE_MAX,
+ .debounce_tol = CONFIG_TOUCHSCREEN_ADS7846_FILTER_DEBOUNCE_TOL,
+ .debounce_rep = CONFIG_TOUCHSCREEN_ADS7846_FILTER_DEBOUNCE_REP,
.get_pendown_state = ads7846_get_pendown_state,
.keep_vref_on = 1,
};
diff --git a/drivers/input/touchscreen/Kconfig b/drivers/input/
touchscreen/Kconfig
index 5bd3bfa..b1540f1 100644
--- a/drivers/input/touchscreen/Kconfig
+++ b/drivers/input/touchscreen/Kconfig
@@ -29,6 +29,31 @@ config TOUCHSCREEN_ADS7846
To compile this driver as a module, choose M here: the
module will be called ads7846.
+config TOUCHSCREEN_ADS7846_FILTER_DEBOUNCE_MAX
+ int "Touchscreen filter debounce max"
+ depends on TOUCHSCREEN_ADS7846
+ range 1 50
+ default 20
+ help
+ Max number of additional readings per sample.
+
+config TOUCHSCREEN_ADS7846_FILTER_DEBOUNCE_TOL
+ int "Touchscreen filter debounce tollerance"
+ depends on TOUCHSCREEN_ADS7846
+ range 1 150
+ default 65
+ help
+ Tolerance used for filtering the touchscreen.
+
+config TOUCHSCREEN_ADS7846_FILTER_DEBOUNCE_REP
+ int "Touchscreen filter debounce repetition"
+ depends on TOUCHSCREEN_ADS7846
+ range 1 10
+ default 1
+ help
+ Additional consecutive good readings required after the
+ first two readings.
+
config TOUCHSCREEN_BITSY
tristate "Compaq iPAQ H3600 (Bitsy) touchscreen"
depends on SA1100_BITSY
diff --git a/drivers/input/touchscreen/ads7846.c b/drivers/input/
touchscreen/ads7846.c
index a68b0a6..2d3b773 100644
--- a/drivers/input/touchscreen/ads7846.c
+++ b/drivers/input/touchscreen/ads7846.c
@@ -17,6 +17,8 @@
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
+
+
#include <linux/hwmon.h>
#include <linux/init.h>
#include <linux/err.h>
@@ -95,6 +97,7 @@ struct ads7846 {
u16 vref_mv;
u16 vref_delay_usecs;
u16 x_plate_ohms;
+ u16 y_plate_ohms;
u16 pressure_max;
struct ads7846_packet *packet;
@@ -533,7 +536,12 @@ static void ads7846_rx(void *ads)
y = packet->tc.y;
z1 = packet->tc.z1;
z2 = packet->tc.z2;
-
+#ifdef VERBOSE
+ printk("ADS7846: Kernel settings x-plate:%d ohms, y-plate:%d
ohms\n",
+ CONFIG_PANEL_SAMSUNG_LTE430WQ_FOC_RESISTANCE_X_PLATE,
+ CONFIG_PANEL_SAMSUNG_LTE430WQ_FOC_RESISTANCE_Y_PLATE);
+ printk("ADS7846: Sensor values x:%d, y:%d, z1:%d, z2:%d, x-plate:%d
ohms, y-plate:%d ohms\n", x, y, z1, z2, ts->x_plate_ohms, ts-
>y_plate_ohms);
+#endif
/* range filtering */
if (x == MAX_12BIT)
x = 0;
@@ -541,13 +549,17 @@ static void ads7846_rx(void *ads)
if (ts->model == 7843) {
Rt = ts->pressure_max / 2;
} else if (likely(x && z1)) {
- /* compute touch pressure resistance using equation #2 */
- Rt = z2;
- Rt -= z1;
- Rt *= x;
+ /* compute touch pressure resistance using
+ equation #2: Rt = ts->x_plate_ohms * (x / 4096) * ((z2 - z1) /
z1) */
+ Rt = z2;
+ Rt -= z1;
Rt *= ts->x_plate_ohms;
+ Rt *= x;
+ Rt /= 4096;
Rt /= z1;
- Rt = (Rt + 2047) >> 12;
+#ifdef VERBOSE
+ printk("ADS7846: computed touch pressure rt = %d\n", Rt);
+#endif
} else {
Rt = 0;
}
@@ -558,7 +570,7 @@ static void ads7846_rx(void *ads)
*/
if (packet->tc.ignore || Rt > ts->pressure_max) {
#ifdef VERBOSE
- pr_debug("%s: ignored %d pressure %d\n",
+ printk("%s: ignored %d pressure %d\n",
dev_name(&ts->spi->dev), packet->tc.ignore, Rt);
#endif
hrtimer_start(&ts->timer, ktime_set(0, TS_POLL_PERIOD),
@@ -927,6 +939,7 @@ static int __devinit ads7846_probe(struct
spi_device *spi)
ts->model = pdata->model ? : 7846;
ts->vref_delay_usecs = pdata->vref_delay_usecs ? : 100;
ts->x_plate_ohms = pdata->x_plate_ohms ? : 400;
+ ts->y_plate_ohms = pdata->y_plate_ohms ? : 400;
ts->pressure_max = pdata->pressure_max ? : ~0;
if (pdata->filter != NULL) {
diff --git a/drivers/video/omap2/displays/Kconfig b/drivers/video/
omap2/displays/Kconfig
index 3feecee..cfa6e34 100644
--- a/drivers/video/omap2/displays/Kconfig
+++ b/drivers/video/omap2/displays/Kconfig
@@ -13,6 +13,24 @@ config PANEL_SAMSUNG_LTE430WQ_F0C
help
LCD Panel used on Overo Palo43
+config PANEL_SAMSUNG_LTE430WQ_FOC_RESISTANCE_X_PLATE
+ int "LCD Panel X Plate Resistance in ohms"
+ depends on PANEL_SAMSUNG_LTE430WQ_F0C
+ range 100 900
+ default 100
+ help
+ LCD Panel X plate resistance in ohms, used for
+ calculating touchscreen pressure.
+
+config PANEL_SAMSUNG_LTE430WQ_FOC_RESISTANCE_Y_PLATE
+ int "LCD Panel Y Plate Resistance in ohms"
+ depends on PANEL_SAMSUNG_LTE430WQ_F0C
+ range 100 900
+ default 100
+ help
+ LCD Panel Y plate resistance in ohms, used for
+ calculating touchscreen pressure.
+
config PANEL_SHARP_LS037V7DW01
tristate "Sharp LS037V7DW01 LCD Panel"
depends on OMAP2_DSS
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