commit b98abe52fa8e ("Input: add common DT binding for touchscreens") introduced common DT bindings for touchscreens [1] and a helper function to parse the DT. This has been integrated and interpretation of the inversion (flipping) properties for the x and y axis has been added to accommodate any orientation of the touch in relation to the LCD. By scaling the min/max ADC values to the screen size it is now possible to pre-calibrate the touch so that is (almost) exactly matches the LCD it is glued onto. This allows to well enough operate the touch before a user space calibration can improve the precision. [1]: Documentation/devicetree/bindings/input/touchscreen/touchscreen.txt Signed-off-by: H. Nikolaus Schaller <hns@xxxxxxxxxxxxx> --- .../devicetree/bindings/input/ads7846.txt | 8 ++- drivers/input/touchscreen/ads7846.c | 72 ++++++++++++++++++++-- 2 files changed, 74 insertions(+), 6 deletions(-) diff --git a/Documentation/devicetree/bindings/input/ads7846.txt b/Documentation/devicetree/bindings/input/ads7846.txt index df8b127..ae56355 100644 --- a/Documentation/devicetree/bindings/input/ads7846.txt +++ b/Documentation/devicetree/bindings/input/ads7846.txt @@ -26,12 +26,17 @@ 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). ti,keep-vref-on set to keep vref on for differential measurements as well - ti,swap-xy swap x and y axis 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, @@ -79,6 +84,7 @@ 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 04edc8f..4525f00 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 +110,14 @@ 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; bool swap_xy; + bool invert_x; + bool invert_y; bool use_internal; struct ads7846_packet *packet; @@ -828,9 +835,48 @@ static void ads7846_report_state(struct ads7846 *ts) if (Rt) { struct input_dev *input = ts->input; + dev_dbg(&ts->spi->dev, + "Raw point(%4d,%4d), pressure (%4u)\n", + x, y, Rt); + /* clamp to expected ADC range */ + if (x < ts->x_min) + x = ts->x_min; + if (x > ts->x_max) + x = ts->x_max; + if (y < ts->y_min) + y = ts->y_min; + if (y > ts->y_max) + y = ts->y_max; + + dev_dbg(&ts->spi->dev, + "Clamped point(%4d,%4d), pressure (%4u)\n", + x, y, Rt); + + /* flip */ + if (ts->invert_x) + x = (ts->x_max - x) + ts->x_min; + if (ts->invert_y) + y = (ts->y_max - y) + ts->y_min; + + dev_dbg(&ts->spi->dev, + "Flipped point(%4d,%4d), pressure (%4u)\n", + x, y, Rt); + + /* scale to desired output range */ + x = (input->absinfo[ABS_X].maximum * (x - ts->x_min)) + / (ts->x_max - ts->x_min); + y = (input->absinfo[ABS_Y].maximum * (y - ts->y_min)) + / (ts->y_max - ts->y_min); + + dev_dbg(&ts->spi->dev, + "Scaled point(%4d,%4d), pressure (%4u)\n", + x, y, Rt); + + /* swap x and y */ if (ts->swap_xy) swap(x, y); + /* report event */ if (!ts->pendown) { input_report_key(input, BTN_TOUCH, 1); ts->pendown = true; @@ -1213,7 +1259,7 @@ static const struct ads7846_platform_data *ads7846_probe_dt(struct device *dev) of_property_read_u16(node, "ti,vref-mv", &pdata->vref_mv); pdata->keep_vref_on = of_property_read_bool(node, "ti,keep-vref-on"); - pdata->swap_xy = of_property_read_bool(node, "ti,swap-xy"); + pdata->swap_xy = of_property_read_bool(node, "touchscreen-swapped-x-y"); of_property_read_u16(node, "ti,settle-delay-usec", &pdata->settle_delay_usecs); @@ -1358,17 +1404,33 @@ static int ads7846_probe(struct spi_device *spi) input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS); 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_dev->absinfo[ABS_X].minimum = 0; + input_dev->absinfo[ABS_Y].minimum = 0; + ts->invert_x = of_property_read_bool(spi->dev.of_node, + "touchscreen-inverted-x"); + ts->invert_y = of_property_read_bool(spi->dev.of_node, + "touchscreen-inverted-y"); + touchscreen_parse_properties(input_dev, false); + } + ads7846_setup_spi_msg(ts, pdata); ts->reg = regulator_get(&spi->dev, "vcc"); -- 2.5.1 -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html