// SPDX-License-Identifier: GPL-2.0-or-later /* * AD7879/AD7889 based touchscreen and GPIO driver * * Copyright (C) 2008-2010 Michael Hennerich, Analog Devices Inc. * * History: * Copyright (c) 2005 David Brownell * Copyright (c) 2006 Nokia Corporation * Various changes: Imre Deak * * Using code from: * - corgi_ts.c * Copyright (C) 2004-2005 Richard Purdie * - omap_ts.[hc], ads7846.h, ts_osk.c * Copyright (C) 2002 MontaVista Software * Copyright (C) 2004 Texas Instruments * Copyright (C) 2005 Dirk Behme * - ad7877.c * Copyright (C) 2006-2008 Analog Devices Inc. */ #include #include #include #include #include #include #include #include #include #include #include #include "ad7879.h" #define AD7879_REG_ZEROS 0 #define AD7879_REG_CTRL1 1 #define AD7879_REG_CTRL2 2 #define AD7879_REG_CTRL3 3 #define AD7879_REG_AUX1HIGH 4 #define AD7879_REG_AUX1LOW 5 #define AD7879_REG_TEMP1HIGH 6 #define AD7879_REG_TEMP1LOW 7 #define AD7879_REG_XPLUS 8 #define AD7879_REG_YPLUS 9 #define AD7879_REG_Z1 10 #define AD7879_REG_Z2 11 #define AD7879_REG_AUXVBAT 12 #define AD7879_REG_TEMP 13 #define AD7879_REG_REVID 14 /* Control REG 1 */ #define AD7879_TMR(x) ((x & 0xFF) << 0) #define AD7879_ACQ(x) ((x & 0x3) << 8) #define AD7879_MODE_NOC (0 << 10) /* Do not convert */ #define AD7879_MODE_SCC (1 << 10) /* Single channel conversion */ #define AD7879_MODE_SEQ0 (2 << 10) /* Sequence 0 in Slave Mode */ #define AD7879_MODE_SEQ1 (3 << 10) /* Sequence 1 in Master Mode */ #define AD7879_MODE_INT (1 << 15) /* PENIRQ disabled INT enabled */ /* Control REG 2 */ #define AD7879_FCD(x) ((x & 0x3) << 0) #define AD7879_RESET (1 << 4) #define AD7879_MFS(x) ((x & 0x3) << 5) #define AD7879_AVG(x) ((x & 0x3) << 7) #define AD7879_SER (1 << 9) /* non-differential */ #define AD7879_DFR (0 << 9) /* differential */ #define AD7879_GPIOPOL (1 << 10) #define AD7879_GPIODIR (1 << 11) #define AD7879_GPIO_DATA (1 << 12) #define AD7879_GPIO_EN (1 << 13) #define AD7879_PM(x) ((x & 0x3) << 14) #define AD7879_PM_SHUTDOWN (0) #define AD7879_PM_DYN (1) #define AD7879_PM_FULLON (2) /* Control REG 3 */ #define AD7879_TEMPMASK_BIT (1<<15) #define AD7879_AUXVBATMASK_BIT (1<<14) #define AD7879_INTMODE_BIT (1<<13) #define AD7879_GPIOALERTMASK_BIT (1<<12) #define AD7879_AUXLOW_BIT (1<<11) #define AD7879_AUXHIGH_BIT (1<<10) #define AD7879_TEMPLOW_BIT (1<<9) #define AD7879_TEMPHIGH_BIT (1<<8) #define AD7879_YPLUS_BIT (1<<7) #define AD7879_XPLUS_BIT (1<<6) #define AD7879_Z1_BIT (1<<5) #define AD7879_Z2_BIT (1<<4) #define AD7879_AUX_BIT (1<<3) #define AD7879_VBAT_BIT (1<<2) #define AD7879_TEMP_BIT (1<<1) enum { AD7879_SEQ_YPOS = 0, AD7879_SEQ_XPOS = 1, AD7879_SEQ_Z1 = 2, AD7879_SEQ_Z2 = 3, AD7879_NR_SENSE = 4, }; #define MAX_12BIT ((1<<12)-1) #define TS_PEN_UP_TIMEOUT msecs_to_jiffies(50) struct ad7879 { struct regmap *regmap; struct device *dev; struct input_dev *input; struct timer_list timer; #ifdef CONFIG_GPIOLIB struct gpio_chip gc; struct mutex mutex; #endif unsigned int irq; bool disabled; /* P: input->mutex */ bool suspended; /* P: input->mutex */ bool swap_xy; u16 conversion_data[AD7879_NR_SENSE]; char phys[32]; u8 first_conversion_delay; u8 acquisition_time; u8 averaging; u8 pen_down_acc_interval; u8 median; u16 x_plate_ohms; u16 cmd_crtl1; u16 cmd_crtl2; u16 cmd_crtl3; int x; int y; int Rt; }; static int ad7879_read(struct ad7879 *ts, u8 reg) { unsigned int val; int error; error = regmap_read(ts->regmap, reg, &val); if (error) { dev_err(ts->dev, "failed to read register %#02x: %d\n", reg, error); return error; } return val; } static int ad7879_write(struct ad7879 *ts, u8 reg, u16 val) { int error; error = regmap_write(ts->regmap, reg, val); if (error) { dev_err(ts->dev, "failed to write %#04x to register %#02x: %d\n", val, reg, error); return error; } return 0; } static int ad7879_report(struct ad7879 *ts) { struct input_dev *input_dev = ts->input; unsigned Rt; u16 x, y, z1, z2; x = ts->conversion_data[AD7879_SEQ_XPOS] & MAX_12BIT; y = ts->conversion_data[AD7879_SEQ_YPOS] & MAX_12BIT; z1 = ts->conversion_data[AD7879_SEQ_Z1] & MAX_12BIT; z2 = ts->conversion_data[AD7879_SEQ_Z2] & MAX_12BIT; if (ts->swap_xy) swap(x, y); /* * The samples processed here are already preprocessed by the AD7879. * The preprocessing function consists of a median and an averaging * filter. The combination of these two techniques provides a robust * solution, discarding the spurious noise in the signal and keeping * only the data of interest. The size of both filters is * programmable. (dev.platform_data, see linux/platform_data/ad7879.h) * Other user-programmable conversion controls include variable * acquisition time, and first conversion delay. Up to 16 averages can * be taken per conversion. */ if (likely(x && z1)) { /* compute touch pressure resistance using equation #1 */ Rt = (z2 - z1) * x * ts->x_plate_ohms; Rt /= z1; Rt = (Rt + 2047) >> 12; /* * Sample found inconsistent, pressure is beyond * the maximum. Don't report it to user space. */ if (Rt > input_abs_get_max(input_dev, ABS_PRESSURE)) return -EINVAL; /* * Note that we delay reporting events by one sample. * This is done to avoid reporting last sample of the * touch sequence, which may be incomplete if finger * leaves the surface before last reading is taken. */ if (timer_pending(&ts->timer)) { /* Touch continues */ input_report_key(input_dev, BTN_TOUCH, 1); input_report_abs(input_dev, ABS_X, ts->x); input_report_abs(input_dev, ABS_Y, ts->y); input_report_abs(input_dev, ABS_PRESSURE, ts->Rt); input_sync(input_dev); } ts->x = x; ts->y = y; ts->Rt = Rt; return 0; } return -EINVAL; } static void ad7879_ts_event_release(struct ad7879 *ts) { struct input_dev *input_dev = ts->input; input_report_abs(input_dev, ABS_PRESSURE, 0); input_report_key(input_dev, BTN_TOUCH, 0); input_sync(input_dev); } static void ad7879_timer(struct timer_list *t) { struct ad7879 *ts = from_timer(ts, t, timer); ad7879_ts_event_release(ts); } static irqreturn_t ad7879_irq(int irq, void *handle) { struct ad7879 *ts = handle; int error; error = regmap_bulk_read(ts->regmap, AD7879_REG_XPLUS, ts->conversion_data, AD7879_NR_SENSE); if (error) dev_err_ratelimited(ts->dev, "failed to read %#02x: %d\n", AD7879_REG_XPLUS, error); else if (!ad7879_report(ts)) mod_timer(&ts->timer, jiffies + TS_PEN_UP_TIMEOUT); return IRQ_HANDLED; } static void __ad7879_enable(struct ad7879 *ts) { ad7879_write(ts, AD7879_REG_CTRL2, ts->cmd_crtl2); ad7879_write(ts, AD7879_REG_CTRL3, ts->cmd_crtl3); ad7879_write(ts, AD7879_REG_CTRL1, ts->cmd_crtl1); enable_irq(ts->irq); } static void __ad7879_disable(struct ad7879 *ts) { u16 reg = (ts->cmd_crtl2 & ~AD7879_PM(-1)) | AD7879_PM(AD7879_PM_SHUTDOWN); disable_irq(ts->irq); if (del_timer_sync(&ts->timer)) ad7879_ts_event_release(ts); ad7879_write(ts, AD7879_REG_CTRL2, reg); } static int ad7879_open(struct input_dev *input) { struct ad7879 *ts = input_get_drvdata(input); /* protected by input->mutex */ if (!ts->disabled && !ts->suspended) __ad7879_enable(ts); return 0; } static void ad7879_close(struct input_dev *input) { struct ad7879 *ts = input_get_drvdata(input); /* protected by input->mutex */ if (!ts->disabled && !ts->suspended) __ad7879_disable(ts); } static int __maybe_unused ad7879_suspend(struct device *dev) { struct ad7879 *ts = dev_get_drvdata(dev); mutex_lock(&ts->input->mutex); if (!ts->suspended && !ts->disabled && ts->input->users) __ad7879_disable(ts); ts->suspended = true; mutex_unlock(&ts->input->mutex); return 0; } static int __maybe_unused ad7879_resume(struct device *dev) { struct ad7879 *ts = dev_get_drvdata(dev); mutex_lock(&ts->input->mutex); if (ts->suspended && !ts->disabled && ts->input->users) __ad7879_enable(ts); ts->suspended = false; mutex_unlock(&ts->input->mutex); return 0; } SIMPLE_DEV_PM_OPS(ad7879_pm_ops, ad7879_suspend, ad7879_resume); EXPORT_SYMBOL(ad7879_pm_ops); static void ad7879_toggle(struct ad7879 *ts, bool disable) { mutex_lock(&ts->input->mutex); if (!ts->suspended && ts->input->users != 0) { if (disable) { if (ts->disabled) __ad7879_enable(ts); } else { if (!ts->disabled) __ad7879_disable(ts); } } ts->disabled = disable; mutex_unlock(&ts->input->mutex); } static ssize_t ad7879_disable_show(struct device *dev, struct device_attribute *attr, char *buf) { struct ad7879 *ts = dev_get_drvdata(dev); return sprintf(buf, "%u\n", ts->disabled); } static ssize_t ad7879_disable_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) { struct ad7879 *ts = dev_get_drvdata(dev); unsigned int val; int error; error = kstrtouint(buf, 10, &val); if (error) return error; ad7879_toggle(ts, val); return count; } static DEVICE_ATTR(disable, 0664, ad7879_disable_show, ad7879_disable_store); static struct attribute *ad7879_attributes[] = { &dev_attr_disable.attr, NULL }; static const struct attribute_group ad7879_attr_group = { .attrs = ad7879_attributes, }; #ifdef CONFIG_GPIOLIB static int ad7879_gpio_direction_input(struct gpio_chip *chip, unsigned gpio) { struct ad7879 *ts = gpiochip_get_data(chip); int err; mutex_lock(&ts->mutex); ts->cmd_crtl2 |= AD7879_GPIO_EN | AD7879_GPIODIR | AD7879_GPIOPOL; err = ad7879_write(ts, AD7879_REG_CTRL2, ts->cmd_crtl2); mutex_unlock(&ts->mutex); return err; } static int ad7879_gpio_direction_output(struct gpio_chip *chip, unsigned gpio, int level) { struct ad7879 *ts = gpiochip_get_data(chip); int err; mutex_lock(&ts->mutex); ts->cmd_crtl2 &= ~AD7879_GPIODIR; ts->cmd_crtl2 |= AD7879_GPIO_EN | AD7879_GPIOPOL; if (level) ts->cmd_crtl2 |= AD7879_GPIO_DATA; else ts->cmd_crtl2 &= ~AD7879_GPIO_DATA; err = ad7879_write(ts, AD7879_REG_CTRL2, ts->cmd_crtl2); mutex_unlock(&ts->mutex); return err; } static int ad7879_gpio_get_value(struct gpio_chip *chip, unsigned gpio) { struct ad7879 *ts = gpiochip_get_data(chip); u16 val; mutex_lock(&ts->mutex); val = ad7879_read(ts, AD7879_REG_CTRL2); mutex_unlock(&ts->mutex); return !!(val & AD7879_GPIO_DATA); } static void ad7879_gpio_set_value(struct gpio_chip *chip, unsigned gpio, int value) { struct ad7879 *ts = gpiochip_get_data(chip); mutex_lock(&ts->mutex); if (value) ts->cmd_crtl2 |= AD7879_GPIO_DATA; else ts->cmd_crtl2 &= ~AD7879_GPIO_DATA; ad7879_write(ts, AD7879_REG_CTRL2, ts->cmd_crtl2); mutex_unlock(&ts->mutex); } static int ad7879_gpio_add(struct ad7879 *ts) { int ret = 0; mutex_init(&ts->mutex); /* Do not create a chip unless flagged for it */ if (!device_property_read_bool(ts->dev, "gpio-controller")) return 0; ts->gc.direction_input = ad7879_gpio_direction_input; ts->gc.direction_output = ad7879_gpio_direction_output; ts->gc.get = ad7879_gpio_get_value; ts->gc.set = ad7879_gpio_set_value; ts->gc.can_sleep = 1; ts->gc.base = -1; ts->gc.ngpio = 1; ts->gc.label = "AD7879-GPIO"; ts->gc.owner = THIS_MODULE; ts->gc.parent = ts->dev; ret = devm_gpiochip_add_data(ts->dev, &ts->gc, ts); if (ret) dev_err(ts->dev, "failed to register gpio %d\n", ts->gc.base); return ret; } #else static int ad7879_gpio_add(struct ad7879 *ts) { return 0; } #endif static int ad7879_parse_dt(struct device *dev, struct ad7879 *ts) { int err; u32 tmp; err = device_property_read_u32(dev, "adi,resistance-plate-x", &tmp); if (err) { dev_err(dev, "failed to get resistance-plate-x property\n"); return err; } ts->x_plate_ohms = (u16)tmp; device_property_read_u8(dev, "adi,first-conversion-delay", &ts->first_conversion_delay); device_property_read_u8(dev, "adi,acquisition-time", &ts->acquisition_time); device_property_read_u8(dev, "adi,median-filter-size", &ts->median); device_property_read_u8(dev, "adi,averaging", &ts->averaging); device_property_read_u8(dev, "adi,conversion-interval", &ts->pen_down_acc_interval); ts->swap_xy = device_property_read_bool(dev, "touchscreen-swapped-x-y"); return 0; } int ad7879_probe(struct device *dev, struct regmap *regmap, int irq, u16 bustype, u8 devid) { struct ad7879 *ts; struct input_dev *input_dev; int err; u16 revid; if (irq <= 0) { dev_err(dev, "No IRQ specified\n"); return -EINVAL; } ts = devm_kzalloc(dev, sizeof(*ts), GFP_KERNEL); if (!ts) return -ENOMEM; err = ad7879_parse_dt(dev, ts); if (err) return err; input_dev = devm_input_allocate_device(dev); if (!input_dev) { dev_err(dev, "Failed to allocate input device\n"); return -ENOMEM; } ts->dev = dev; ts->input = input_dev; ts->irq = irq; ts->regmap = regmap; timer_setup(&ts->timer, ad7879_timer, 0); snprintf(ts->phys, sizeof(ts->phys), "%s/input0", dev_name(dev)); input_dev->name = "AD7879 Touchscreen"; input_dev->phys = ts->phys; input_dev->dev.parent = dev; input_dev->id.bustype = bustype; input_dev->open = ad7879_open; input_dev->close = ad7879_close; input_set_drvdata(input_dev, ts); input_set_capability(input_dev, EV_KEY, BTN_TOUCH); input_set_abs_params(input_dev, ABS_X, 0, MAX_12BIT, 0, 0); input_set_abs_params(input_dev, ABS_Y, 0, MAX_12BIT, 0, 0); input_set_capability(input_dev, EV_ABS, ABS_PRESSURE); touchscreen_parse_properties(input_dev, false, NULL); if (!input_abs_get_max(input_dev, ABS_PRESSURE)) { dev_err(dev, "Touchscreen pressure is not specified\n"); return -EINVAL; } err = ad7879_write(ts, AD7879_REG_CTRL2, AD7879_RESET); if (err < 0) { dev_err(dev, "Failed to write %s\n", input_dev->name); return err; } revid = ad7879_read(ts, AD7879_REG_REVID); input_dev->id.product = (revid & 0xff); input_dev->id.version = revid >> 8; if (input_dev->id.product != devid) { dev_err(dev, "Failed to probe %s (%x vs %x)\n", input_dev->name, devid, revid); return -ENODEV; } ts->cmd_crtl3 = AD7879_YPLUS_BIT | AD7879_XPLUS_BIT | AD7879_Z2_BIT | AD7879_Z1_BIT | AD7879_TEMPMASK_BIT | AD7879_AUXVBATMASK_BIT | AD7879_GPIOALERTMASK_BIT; ts->cmd_crtl2 = AD7879_PM(AD7879_PM_DYN) | AD7879_DFR | AD7879_AVG(ts->averaging) | AD7879_MFS(ts->median) | AD7879_FCD(ts->first_conversion_delay); ts->cmd_crtl1 = AD7879_MODE_INT | AD7879_MODE_SEQ1 | AD7879_ACQ(ts->acquisition_time) | AD7879_TMR(ts->pen_down_acc_interval); err = devm_request_threaded_irq(dev, ts->irq, NULL, ad7879_irq, IRQF_TRIGGER_FALLING | IRQF_ONESHOT, dev_name(dev), ts); if (err) { dev_err(dev, "Failed to request IRQ: %d\n", err); return err; } __ad7879_disable(ts); err = devm_device_add_group(dev, &ad7879_attr_group); if (err) return err; err = ad7879_gpio_add(ts); if (err) return err; err = input_register_device(input_dev); if (err) return err; dev_set_drvdata(dev, ts); return 0; } EXPORT_SYMBOL(ad7879_probe); MODULE_AUTHOR("Michael Hennerich "); MODULE_DESCRIPTION("AD7879(-1) touchscreen Driver"); MODULE_LICENSE("GPL");