The Colibri Vybrid VF50 module supports 4-wire touchscreens using FETs and ADC inputs. This driver uses the IIO consumer interface and relies on the vf610_adc driver based on the IIO framework. Signed-off-by: Sanchayan Maity <maitysanchayan@xxxxxxxxx> --- drivers/input/touchscreen/Kconfig | 12 + drivers/input/touchscreen/Makefile | 1 + drivers/input/touchscreen/colibri-vf50-ts.c | 451 ++++++++++++++++++++++++++++ 3 files changed, 464 insertions(+) create mode 100644 drivers/input/touchscreen/colibri-vf50-ts.c diff --git a/drivers/input/touchscreen/Kconfig b/drivers/input/touchscreen/Kconfig index 80f6386..28948ca 100644 --- a/drivers/input/touchscreen/Kconfig +++ b/drivers/input/touchscreen/Kconfig @@ -1027,4 +1027,16 @@ config TOUCHSCREEN_ZFORCE To compile this driver as a module, choose M here: the module will be called zforce_ts. +config TOUCHSCREEN_COLIBRI_VF50 + tristate "Toradex Colibri on board touchscreen driver" + depends on GPIOLIB && IIO && VF610_ADC + help + Say Y here if you have a Colibri VF50 and plan to use + the on-board provided 4-wire touchscreen driver. + + If unsure, say N. + + To compile this driver as a module, choose M here: the + module will be called colibri_vf50_ts. + endif diff --git a/drivers/input/touchscreen/Makefile b/drivers/input/touchscreen/Makefile index 44deea7..93746a0 100644 --- a/drivers/input/touchscreen/Makefile +++ b/drivers/input/touchscreen/Makefile @@ -84,3 +84,4 @@ obj-$(CONFIG_TOUCHSCREEN_W90X900) += w90p910_ts.o obj-$(CONFIG_TOUCHSCREEN_SX8654) += sx8654.o obj-$(CONFIG_TOUCHSCREEN_TPS6507X) += tps6507x-ts.o obj-$(CONFIG_TOUCHSCREEN_ZFORCE) += zforce_ts.o +obj-$(CONFIG_TOUCHSCREEN_COLIBRI_VF50) += colibri-vf50-ts.o diff --git a/drivers/input/touchscreen/colibri-vf50-ts.c b/drivers/input/touchscreen/colibri-vf50-ts.c new file mode 100644 index 0000000..eb16bdc --- /dev/null +++ b/drivers/input/touchscreen/colibri-vf50-ts.c @@ -0,0 +1,451 @@ +/* Copyright 2015 Toradex AG + * + * Toradex Colibri VF50 Touchscreen driver + * + * Originally authored by Stefan Agner for 3.0 kernel + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + */ + +#include <dt-bindings/gpio/gpio.h> +#include <linux/delay.h> +#include <linux/err.h> +#include <linux/gpio.h> +#include <linux/iio/consumer.h> +#include <linux/iio/types.h> +#include <linux/input.h> +#include <linux/interrupt.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/of_gpio.h> +#include <linux/pinctrl/consumer.h> +#include <linux/platform_device.h> +#include <linux/slab.h> +#include <linux/types.h> + +#define DRIVER_NAME "colibri-vf50-ts" +#define DRV_VERSION "1.0" + +#define VF_ADC_MAX ((1 << 12) - 1) + +#define COLI_TOUCH_MIN_DELAY_US 1000 +#define COLI_TOUCH_MAX_DELAY_US 2000 + +static int min_pressure = 200; + +struct vf50_touch_device { + struct platform_device *pdev; + struct input_dev *ts_input; + struct workqueue_struct *ts_workqueue; + struct work_struct ts_work; + struct iio_channel *channels; + struct gpio_desc *gpio_xp; + struct gpio_desc *gpio_xm; + struct gpio_desc *gpio_yp; + struct gpio_desc *gpio_ym; + struct gpio_desc *gpio_pen_detect; + struct gpio_desc *gpio_pen_detect_pullup; + int pen_irq; + bool stop_touchscreen; +}; + +/* + * Enables given plates and measures touch parameters using ADC + */ +static int adc_ts_measure(struct iio_channel *channel, + struct gpio_desc *plate_p, struct gpio_desc *plate_m) +{ + int i, value = 0, val = 0; + int ret; + + gpiod_set_value(plate_p, 1); + gpiod_set_value(plate_m, 1); + + usleep_range(COLI_TOUCH_MIN_DELAY_US, COLI_TOUCH_MAX_DELAY_US); + + for (i = 0; i < 5; i++) { + ret = iio_read_channel_raw(channel, &val); + if (ret < 0) + return -EINVAL; + + value += val; + } + + value /= 5; + + gpiod_set_value(plate_p, 0); + gpiod_set_value(plate_m, 0); + + return value; +} + +/* + * Enable touch detection using falling edge detection on XM + */ +static void vf50_ts_enable_touch_detection(struct vf50_touch_device *vf50_ts) +{ + /* Enable plate YM (needs to be strong GND, high active) */ + gpiod_set_value(vf50_ts->gpio_ym, 1); + + /* + * Let the platform mux to idle state in order to enable + * Pull-Up on GPIO + */ + pinctrl_pm_select_idle_state(&vf50_ts->pdev->dev); +} + +/* + * ADC touch screen sampling worker function + */ +static void vf50_ts_work(struct work_struct *ts_work) +{ + struct vf50_touch_device *vf50_ts = container_of(ts_work, + struct vf50_touch_device, ts_work); + struct device *dev = &vf50_ts->pdev->dev; + int val_x, val_y, val_z1, val_z2, val_p = 0; + bool discard_val_on_start = true; + + while (!vf50_ts->stop_touchscreen) { + /* X-Direction */ + val_x = adc_ts_measure(&vf50_ts->channels[0], + vf50_ts->gpio_xp, vf50_ts->gpio_xm); + if (val_x < 0) + continue; + + /* Y-Direction */ + val_y = adc_ts_measure(&vf50_ts->channels[1], + vf50_ts->gpio_yp, vf50_ts->gpio_ym); + if (val_y < 0) + continue; + + /* + * Touch pressure + * Measure on XP/YM + */ + val_z1 = adc_ts_measure(&vf50_ts->channels[2], + vf50_ts->gpio_yp, vf50_ts->gpio_xm); + if (val_z1 < 0) + continue; + val_z2 = adc_ts_measure(&vf50_ts->channels[3], + vf50_ts->gpio_yp, vf50_ts->gpio_xm); + if (val_z2 < 0) + continue; + + /* Validate signal (avoid calculation using noise) */ + if (val_z1 > 64 && val_x > 64) { + /* + * Calculate resistance between the plates + * lower resistance means higher pressure + */ + int r_x = (1000 * val_x) / VF_ADC_MAX; + + val_p = (r_x * val_z2) / val_z1 - r_x; + + } else { + val_p = 2000; + } + + val_p = 2000 - val_p; + dev_dbg(dev, "Measured values: x: %d, y: %d, z1: %d, z2: %d, " + "p: %d\n", val_x, val_y, val_z1, val_z2, val_p); + + /* + * If touch pressure is too low, stop measuring and reenable + * touch detection + */ + if (val_p < min_pressure || val_p > 2000) + break; + + /* + * The pressure may not be enough for the first x and the + * second y measurement, but, the pressure is ok when the + * driver is doing the third and fourth measurement. To + * take care of this, we drop the first measurement always. + */ + if (discard_val_on_start) { + discard_val_on_start = false; + } else { + /* + * Report touch position and sleep for + * next measurement + */ + input_report_abs(vf50_ts->ts_input, + ABS_X, VF_ADC_MAX - val_x); + input_report_abs(vf50_ts->ts_input, + ABS_Y, VF_ADC_MAX - val_y); + input_report_abs(vf50_ts->ts_input, + ABS_PRESSURE, val_p); + input_report_key(vf50_ts->ts_input, BTN_TOUCH, 1); + input_sync(vf50_ts->ts_input); + } + + msleep(10); + } + + /* Report no more touch, reenable touch detection */ + input_report_abs(vf50_ts->ts_input, ABS_PRESSURE, 0); + input_report_key(vf50_ts->ts_input, BTN_TOUCH, 0); + input_sync(vf50_ts->ts_input); + + vf50_ts_enable_touch_detection(vf50_ts); + + /* Wait for the pull-up to be stable on high */ + msleep(10); + + /* Reenable IRQ to detect touch */ + enable_irq(vf50_ts->pen_irq); + + dev_dbg(dev, "Reenabled touch detection interrupt\n"); +} + +static irqreturn_t vf50_ts_touched(int irq, void *dev_id) +{ + struct vf50_touch_device *vf50_ts = (struct vf50_touch_device *)dev_id; + struct device *dev = &vf50_ts->pdev->dev; + + dev_dbg(dev, "Touch detected, start worker thread\n"); + + disable_irq_nosync(irq); + + /* Disable the touch detection plates */ + gpiod_set_value(vf50_ts->gpio_ym, 0); + + /* Let the platform mux to default state in order to mux as ADC */ + pinctrl_pm_select_default_state(dev); + + queue_work(vf50_ts->ts_workqueue, &vf50_ts->ts_work); + + return IRQ_HANDLED; +} + +static int vf50_ts_open(struct input_dev *dev_input) +{ + int ret; + struct vf50_touch_device *touchdev = input_get_drvdata(dev_input); + struct device *dev = &touchdev->pdev->dev; + + dev_dbg(dev, "Input device %s opened, starting touch detection\n", + dev_input->name); + + touchdev->stop_touchscreen = false; + + ret = gpiod_direction_output(touchdev->gpio_xp, 0); + if (ret) { + dev_err(dev, "Could not set gpio xp as output %d\n", ret); + return ret; + } + + ret = gpiod_direction_output(touchdev->gpio_xm, 0); + if (ret) { + dev_err(dev, "Could not set gpio xm as output %d\n", ret); + return ret; + } + + ret = gpiod_direction_output(touchdev->gpio_yp, 0); + if (ret) { + dev_err(dev, "Could not set gpio yp as output %d\n", ret); + return ret; + } + + ret = gpiod_direction_output(touchdev->gpio_ym, 0); + if (ret) { + dev_err(dev, "Could not set gpio ym as output %d\n", ret); + return ret; + } + + ret = gpiod_direction_input(touchdev->gpio_pen_detect); + if (ret) { + dev_err(dev, + "Could not set gpio pen detect as input %d\n", ret); + return ret; + } + + ret = gpiod_direction_input(touchdev->gpio_pen_detect_pullup); + if (ret) { + dev_err(dev, + "Could not set pen detect pullup as input %d\n", ret); + return ret; + } + + /* Mux detection before request IRQ, wait for pull-up to settle */ + vf50_ts_enable_touch_detection(touchdev); + msleep(10); + + touchdev->pen_irq = gpiod_to_irq(touchdev->gpio_pen_detect); + if (touchdev->pen_irq < 0) { + dev_err(dev, "Unable to get IRQ for GPIO\n"); + return touchdev->pen_irq; + } + + ret = request_irq(touchdev->pen_irq, vf50_ts_touched, + IRQF_TRIGGER_FALLING, "touch detected", touchdev); + if (ret < 0) { + dev_err(dev, "Unable to request IRQ %d\n", touchdev->pen_irq); + return ret; + } + + return 0; +} + +static void vf50_ts_close(struct input_dev *dev_input) +{ + struct vf50_touch_device *touchdev = input_get_drvdata(dev_input); + struct device *dev = &touchdev->pdev->dev; + + free_irq(touchdev->pen_irq, touchdev); + + touchdev->stop_touchscreen = true; + + /* Wait until touchscreen thread finishes any possible remnants. */ + cancel_work_sync(&touchdev->ts_work); + + dev_dbg(dev, "Input device %s closed, disable touch detection\n", + dev_input->name); +} + +static inline int vf50_ts_get_gpiod(struct device *dev, + struct gpio_desc **gpio_d, const char *con_id) +{ + int ret; + + *gpio_d = devm_gpiod_get(dev, con_id); + if (IS_ERR(*gpio_d)) { + ret = PTR_ERR(*gpio_d); + dev_err(dev, "Could not get gpio_%s %d\n", con_id, ret); + return ret; + } + + return 0; +} + +static int vf50_ts_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct device_node *node = dev->of_node; + struct vf50_touch_device *touchdev; + struct input_dev *input; + int ret = 0; + + if (!node) { + dev_err(dev, "Device does not have associated DT data\n"); + return -EINVAL; + } + + touchdev = devm_kzalloc(dev, sizeof(*touchdev), GFP_KERNEL); + if (touchdev == NULL) + return -ENOMEM; + + input = devm_input_allocate_device(dev); + if (!input) { + dev_err(dev, "Failed to allocate TS input device\n"); + ret = -ENOMEM; + return ret; + } + + platform_set_drvdata(pdev, touchdev); + + touchdev->pdev = pdev; + + input->name = DRIVER_NAME; + input->id.bustype = BUS_HOST; + input->dev.parent = dev; + input->open = vf50_ts_open; + input->close = vf50_ts_close; + + _set_bit(EV_ABS, input->evbit); + _set_bit(EV_KEY, input->evbit); + _set_bit(BTN_TOUCH, input->keybit); + input_set_abs_params(input, ABS_X, 0, VF_ADC_MAX, 0, 0); + input_set_abs_params(input, ABS_Y, 0, VF_ADC_MAX, 0, 0); + input_set_abs_params(input, ABS_PRESSURE, 0, VF_ADC_MAX, 0, 0); + + touchdev->ts_input = input; + input_set_drvdata(input, touchdev); + ret = input_register_device(input); + if (ret) { + dev_err(dev, "Failed to register input device\n"); + return ret; + } + + ret = vf50_ts_get_gpiod(dev, &touchdev->gpio_xp, "xp"); + if (ret) + return ret; + + ret = vf50_ts_get_gpiod(dev, &touchdev->gpio_xm, "xm"); + if (ret) + return ret; + + ret = vf50_ts_get_gpiod(dev, &touchdev->gpio_yp, "yp"); + if (ret) + return ret; + + ret = vf50_ts_get_gpiod(dev, &touchdev->gpio_ym, "ym"); + if (ret) + return ret; + + ret = vf50_ts_get_gpiod(dev, &touchdev->gpio_pen_detect, + "pen-detect"); + if (ret) + return ret; + + ret = vf50_ts_get_gpiod(dev, &touchdev->gpio_pen_detect_pullup, + "pen-pullup"); + if (ret) + return ret; + + INIT_WORK(&touchdev->ts_work, vf50_ts_work); + touchdev->ts_workqueue = create_singlethread_workqueue("vf50-ts-touch"); + + if (!touchdev->ts_workqueue) { + ret = PTR_ERR(touchdev->ts_workqueue); + dev_err(dev, + "Failed creating vf50-ts-touch workqueue %d\n", ret); + return ret; + } + + touchdev->channels = iio_channel_get_all(dev); + if (IS_ERR(touchdev->channels)) + return PTR_ERR(touchdev->channels); + + dev_info(dev, "Attached colibri-vf50-ts driver successfully\n"); + + return 0; +} + +static int vf50_ts_remove(struct platform_device *pdev) +{ + struct vf50_touch_device *touchdev = platform_get_drvdata(pdev); + + destroy_workqueue(touchdev->ts_workqueue); + iio_channel_release_all(touchdev->channels); + + return 0; +} + +static const struct of_device_id vf50_touch_of_match[] = { + { .compatible = "toradex,vf50-touchctrl", }, + { } +}; +MODULE_DEVICE_TABLE(of, vf50_touch_of_match); + +static struct platform_driver __refdata vf50_touch_driver = { + .driver = { + .name = "toradex,vf50_touchctrl", + .of_match_table = vf50_touch_of_match, + }, + .probe = vf50_ts_probe, + .remove = vf50_ts_remove, + .prevent_deferred_probe = false, +}; + +module_platform_driver(vf50_touch_driver); + +module_param(min_pressure, int, 0600); +MODULE_PARM_DESC(min_pressure, "Minimum pressure for touch detection"); +MODULE_AUTHOR("Sanchayan Maity"); +MODULE_DESCRIPTION("Colibri VF50 Touchscreen driver"); +MODULE_LICENSE("GPL v2"); +MODULE_VERSION(DRV_VERSION); -- 2.4.6 -- 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