commit b98abe52fa8e ("Input: add common DT binding for touchscreens") introduced common DT bindings for touchscreens [1] and a helper function to parse the DT.
commit ed7c9870c9bc ("Input: of_touchscreen - add support for inverted / swapped axes") added another helper for parsing axis inversion and swapping and applying them to x and y coordinates.
Both helpers have been integrated to accommodate any orientation of the touch panel in relation to the LCD.
A new feature is to introduce scaling the min/max ADC values to the screen size.
This makes it possible to pre-calibrate the touch so that is (almost) exactly matches the LCD pixel coordinates it is glued onto. This allows to well enough operate the touch before a user space calibration step can improve the precision.
[1]: Documentation/devicetree/bindings/input/touchscreen/touchscreen.txt
Signed-off-by: H. Nikolaus Schaller hns@goldelico.com Acked-by: Rob Herring robh@kernel.org --- .../devicetree/bindings/input/ads7846.txt | 9 +++- drivers/input/touchscreen/ads7846.c | 60 ++++++++++++++++++---- 2 files changed, 57 insertions(+), 12 deletions(-)
diff --git a/Documentation/devicetree/bindings/input/ads7846.txt b/Documentation/devicetree/bindings/input/ads7846.txt index 9fc47b0..29f91ed 100644 --- a/Documentation/devicetree/bindings/input/ads7846.txt +++ b/Documentation/devicetree/bindings/input/ads7846.txt @@ -26,6 +26,12 @@ Additional required properties:
Optional properties:
+You can optionally specify any of the touchscreen parameters described in + + Documentation/devicetree/bindings/input/touchscreen/touchscreen.txt + +This allows to scale, invert or swap coordinates and define the fuzz factors. + ti,vref-delay-usecs vref supply delay in usecs, 0 for external vref (u16). ti,vref-mv The VREF voltage, in millivolts (u16). @@ -33,7 +39,7 @@ Optional properties: (ADS7846). ti,keep-vref-on set to keep vref on for differential measurements as well - ti,swap-xy swap x and y axis + ti,swap-xy deprecated name for touchscreen-swapped-x-y ti,settle-delay-usec Settling time of the analog signals; a function of Vcc and the capacitance on the X/Y drivers. If set to non-zero, @@ -82,6 +88,7 @@ Example for a TSC2046 chip connected to an McSPI controller of an OMAP SoC:: pendown-gpio = <&gpio1 8 0>; vcc-supply = <®_vcc3>;
+ touchscreen-swapped-x-y; ti,x-min = /bits/ 16 <0>; ti,x-max = /bits/ 16 <8000>; ti,y-min = /bits/ 16 <0>; diff --git a/drivers/input/touchscreen/ads7846.c b/drivers/input/touchscreen/ads7846.c index 1ce3ecb..400e421 100644 --- a/drivers/input/touchscreen/ads7846.c +++ b/drivers/input/touchscreen/ads7846.c @@ -34,6 +34,7 @@ #include <linux/spi/ads7846.h> #include <linux/regulator/consumer.h> #include <linux/module.h> +#include <linux/input/touchscreen.h> #include <asm/irq.h>
/* @@ -109,8 +110,13 @@ struct ads7846 { u16 vref_delay_usecs; u16 x_plate_ohms; u16 pressure_max; + u16 x_min; + u16 x_max; + u16 y_min; + u16 y_max; + + struct touchscreen_properties prop;
- bool swap_xy; bool use_internal;
struct ads7846_packet *packet; @@ -825,22 +831,36 @@ static void ads7846_report_state(struct ads7846 *ts) */ if (Rt) { struct input_dev *input = ts->input; + int sx, sy; + + dev_dbg(&ts->spi->dev, + "Raw point(%4d,%4d), pressure (%4u)\n", + x, y, Rt); + + /* scale ADC values to desired output range */ + sx = (ts->prop.max_x * (x - ts->x_min)) + / (ts->x_max - ts->x_min); + sy = (ts->prop.max_y * (y - ts->y_min)) + / (ts->y_max - ts->y_min);
- if (ts->swap_xy) - swap(x, y); + dev_dbg(&ts->spi->dev, + "Scaled point(%4d,%4d), pressure (%4u)\n", + sx, sy, Rt);
+ /* report event */ if (!ts->pendown) { input_report_key(input, BTN_TOUCH, 1); ts->pendown = true; dev_vdbg(&ts->spi->dev, "DOWN\n"); }
- input_report_abs(input, ABS_X, x); - input_report_abs(input, ABS_Y, y); + touchscreen_report_pos(ts->input, &ts->prop, + (unsigned int) sx, (unsigned int) sy, + false); input_report_abs(input, ABS_PRESSURE, ts->pressure_max - Rt);
input_sync(input); - dev_vdbg(&ts->spi->dev, "%4d/%4d/%4d\n", x, y, Rt); + dev_vdbg(&ts->spi->dev, "%4d/%4d/%4d\n", sx, sy, Rt); } }
@@ -1212,6 +1232,8 @@ static const struct ads7846_platform_data *ads7846_probe_dt(struct device *dev) pdata->keep_vref_on = of_property_read_bool(node, "ti,keep-vref-on");
pdata->swap_xy = of_property_read_bool(node, "ti,swap-xy"); + if (pdata->swap_xy) + dev_notice(dev, "please update device tree to use touchscreen-swapped-x-y");
of_property_read_u16(node, "ti,settle-delay-usec", &pdata->settle_delay_usecs); @@ -1315,7 +1337,6 @@ static int ads7846_probe(struct spi_device *spi) ts->pressure_max = pdata->pressure_max ? : ~0;
ts->vref_mv = pdata->vref_mv; - ts->swap_xy = pdata->swap_xy;
if (pdata->filter != NULL) { if (pdata->filter_init != NULL) { @@ -1355,18 +1376,35 @@ static int ads7846_probe(struct spi_device *spi) input_dev->dev.parent = &spi->dev;
input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS); + input_dev->absbit[0] = BIT_MASK(ABS_X) | BIT_MASK(ABS_Y) | + BIT_MASK(ABS_PRESSURE); input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH); + + ts->x_min = pdata->x_min ? : 0; + ts->x_max = pdata->x_max ? : MAX_12BIT; + ts->y_min = pdata->y_min ? : 0; + ts->y_max = pdata->y_max ? : MAX_12BIT; + input_set_abs_params(input_dev, ABS_X, - pdata->x_min ? : 0, - pdata->x_max ? : MAX_12BIT, + ts->x_min, + ts->x_max, 0, 0); input_set_abs_params(input_dev, ABS_Y, - pdata->y_min ? : 0, - pdata->y_max ? : MAX_12BIT, + ts->y_min, + ts->y_max, 0, 0); input_set_abs_params(input_dev, ABS_PRESSURE, pdata->pressure_min, pdata->pressure_max, 0, 0);
+ if (spi->dev.of_node) { + input_abs_set_min(input_dev, ABS_X, 0); + input_abs_set_min(input_dev, ABS_Y, 0); + + touchscreen_parse_properties(ts->input, false, &ts->prop); + } + + ts->prop.swap_x_y |= pdata->swap_xy; + ads7846_setup_spi_msg(ts, pdata);
ts->reg = regulator_get(&spi->dev, "vcc");