Input: qt1050 - add Microchip AT42QT1050 support

Microchip AT42QT1050 Five-channel Touch Sensor IC

The AT42QT1050 (QT1050) is a QTouchADC sensor device. The device can sense from

one to five keys, dependent on mode. The QT1050 includes all signal processing

functions necessary to provide stable sensing under a wide variety of changing

conditions, and the outputs are fully debounced.

The touchkey device node should be placed inside an I2C bus node.

Required properties:

- compatible: Must be "microchip,qt1050"

- reg: The I2C address of the device

- interrupts: The sink for the touchpad's IRQ output,

  see ../interrupt-controller/interrupts.txt

Optional properties:

- wakeup-source: touch keys can be used as a wakeup source

Each button (key) is represented as a sub-node:

Each not specified key or key with linux,code set to KEY_RESERVED gets disabled

in HW.

Subnode properties:

- linux,code: Keycode to emit.

- reg: The key number. Valid values: 0, 1, 2, 3, 4.

Optional subnode-properties:

If a optional property is missing or has a invalid value the default value is

taken.

- microchip,pre-charge-time-ns:

  Each touchpad need some time to precharge. The value depends on the mechanical

  layout.

  Valid value range: 0 - 637500; values must be a multiple of 2500;

  default is 0.

- microchip,average-samples:

  Number of data samples which are averaged for each read.

  Valid values: 1, 4, 16, 64, 256, 1024, 4096, 16384; default is 1.

- microchip,average-scaling:

  The scaling factor which is used to scale the average-samples.

  Valid values: 1, 2, 4, 8, 16, 32, 64, 128; default is 1.

- microchip,threshold:

  Number of counts to register a touch detection.

  Valid value range: 0 - 255; default is 20.

Example:

QT1050 with 3 non continuous keys, key2 and key4 are disabled.

touchkeys@41 {

	compatible = "microchip,qt1050";

	reg = <0x41>;

	interrupt-parent = <&gpio0>;

	interrupts = <17 IRQ_TYPE_EDGE_FALLING>;

	up@0 {

		reg = <0>;

		linux,code = <KEY_UP>;

		microchip,average-samples = <64>;

		microchip,average-scaling = <16>;

		microchip,pre-charge-time-ns = <10000>;

	};

	right@1 {

		reg = <1>;

		linux,code = <KEY_RIGHT>;

		microchip,average-samples = <64>;

		microchip,average-scaling = <8>;

	};

	down@3 {

		reg = <3>;

		linux,code = <KEY_DOWN>;

		microchip,average-samples = <256>;

		microchip,average-scaling = <16>;

	};

};

	  right-hand column will be interpreted as the key shown in the

	  left-hand column.

config KEYBOARD_QT1050

	tristate "Microchip AT42QT1050 Touch Sensor Chip"

	depends on I2C

	select REGMAP_I2C

	help

	  Say Y here if you want to use Microchip AT42QT1050 QTouch

	  Sensor chip as input device.

	  To compile this driver as a module, choose M here:

	  the module will be called qt1050

config KEYBOARD_QT1070

       tristate "Atmel AT42QT1070 Touch Sensor Chip"

       depends on I2C

obj-$(CONFIG_KEYBOARD_PMIC8XXX)		+= pmic8xxx-keypad.o

obj-$(CONFIG_KEYBOARD_PXA27x)		+= pxa27x_keypad.o

obj-$(CONFIG_KEYBOARD_PXA930_ROTARY)	+= pxa930_rotary.o

obj-$(CONFIG_KEYBOARD_QT1050)           += qt1050.o

obj-$(CONFIG_KEYBOARD_QT1070)           += qt1070.o

obj-$(CONFIG_KEYBOARD_QT2160)		+= qt2160.o

obj-$(CONFIG_KEYBOARD_SAMSUNG)		+= samsung-keypad.o

// SPDX-License-Identifier: GPL-2.0

/*

 *  Microchip AT42QT1050 QTouch Sensor Controller

 *

 *  Copyright (C) 2019 Pengutronix, Marco Felsch <kernel@pengutronix.de>

 *

 *  Base on AT42QT1070 driver by:

 *  Bo Shen <voice.shen@atmel.com>

 *  Copyright (C) 2011 Atmel

 */

#include <linux/delay.h>

#include <linux/i2c.h>

#include <linux/input.h>

#include <linux/interrupt.h>

#include <linux/kernel.h>

#include <linux/log2.h>

#include <linux/module.h>

#include <linux/of.h>

#include <linux/regmap.h>

/* Chip ID */

#define QT1050_CHIP_ID		0x00

#define QT1050_CHIP_ID_VER	0x46

/* Firmware version */

#define QT1050_FW_VERSION	0x01

/* Detection status */

#define QT1050_DET_STATUS	0x02

/* Key status */

#define QT1050_KEY_STATUS	0x03

/* Key Signals */

#define QT1050_KEY_SIGNAL_0_MSB	0x06

#define QT1050_KEY_SIGNAL_0_LSB	0x07

#define QT1050_KEY_SIGNAL_1_MSB	0x08

#define QT1050_KEY_SIGNAL_1_LSB	0x09

#define QT1050_KEY_SIGNAL_2_MSB	0x0c

#define QT1050_KEY_SIGNAL_2_LSB	0x0d

#define QT1050_KEY_SIGNAL_3_MSB	0x0e

#define QT1050_KEY_SIGNAL_3_LSB	0x0f

#define QT1050_KEY_SIGNAL_4_MSB	0x10

#define QT1050_KEY_SIGNAL_4_LSB	0x11

/* Reference data */

#define QT1050_REF_DATA_0_MSB	0x14

#define QT1050_REF_DATA_0_LSB	0x15

#define QT1050_REF_DATA_1_MSB	0x16

#define QT1050_REF_DATA_1_LSB	0x17

#define QT1050_REF_DATA_2_MSB	0x1a

#define QT1050_REF_DATA_2_LSB	0x1b

#define QT1050_REF_DATA_3_MSB	0x1c

#define QT1050_REF_DATA_3_LSB	0x1d

#define QT1050_REF_DATA_4_MSB	0x1e

#define QT1050_REF_DATA_4_LSB	0x1f

/* Negative threshold level */

#define QT1050_NTHR_0		0x21

#define QT1050_NTHR_1		0x22

#define QT1050_NTHR_2		0x24

#define QT1050_NTHR_3		0x25

#define QT1050_NTHR_4		0x26

/* Pulse / Scale  */

#define QT1050_PULSE_SCALE_0	0x28

#define QT1050_PULSE_SCALE_1	0x29

#define QT1050_PULSE_SCALE_2	0x2b

#define QT1050_PULSE_SCALE_3	0x2c

#define QT1050_PULSE_SCALE_4	0x2d

/* Detection integrator counter / AKS */

#define QT1050_DI_AKS_0		0x2f

#define QT1050_DI_AKS_1		0x30

#define QT1050_DI_AKS_2		0x32

#define QT1050_DI_AKS_3		0x33

#define QT1050_DI_AKS_4		0x34

/* Charge Share Delay */

#define QT1050_CSD_0		0x36

#define QT1050_CSD_1		0x37

#define QT1050_CSD_2		0x39

#define QT1050_CSD_3		0x3a

#define QT1050_CSD_4		0x3b

/* Low Power Mode */

#define QT1050_LPMODE		0x3d

/* Calibration and Reset */

#define QT1050_RES_CAL		0x3f

#define QT1050_RES_CAL_RESET		BIT(7)

#define QT1050_RES_CAL_CALIBRATE	BIT(1)

#define QT1050_MAX_KEYS		5

#define QT1050_RESET_TIME	255

struct qt1050_key_regs {

	unsigned int nthr;

	unsigned int pulse_scale;

	unsigned int di_aks;

	unsigned int csd;

};

struct qt1050_key {

	u32 num;

	u32 charge_delay;

	u32 thr_cnt;

	u32 samples;

	u32 scale;

	u32 keycode;

};

struct qt1050_priv {

	struct i2c_client	*client;

	struct input_dev	*input;

	struct regmap		*regmap;

	struct qt1050_key	keys[QT1050_MAX_KEYS];

	unsigned short		keycodes[QT1050_MAX_KEYS];

	u8			reg_keys;

	u8			last_keys;

};

static const struct qt1050_key_regs qt1050_key_regs_data[] = {

	{

		.nthr = QT1050_NTHR_0,

		.pulse_scale = QT1050_PULSE_SCALE_0,

		.di_aks = QT1050_DI_AKS_0,

		.csd = QT1050_CSD_0,

	}, {

		.nthr = QT1050_NTHR_1,

		.pulse_scale = QT1050_PULSE_SCALE_1,

		.di_aks = QT1050_DI_AKS_1,

		.csd = QT1050_CSD_1,

	}, {

		.nthr = QT1050_NTHR_2,

		.pulse_scale = QT1050_PULSE_SCALE_2,

		.di_aks = QT1050_DI_AKS_2,

		.csd = QT1050_CSD_2,

	}, {

		.nthr = QT1050_NTHR_3,

		.pulse_scale = QT1050_PULSE_SCALE_3,

		.di_aks = QT1050_DI_AKS_3,

		.csd = QT1050_CSD_3,

	}, {

		.nthr = QT1050_NTHR_4,

		.pulse_scale = QT1050_PULSE_SCALE_4,

		.di_aks = QT1050_DI_AKS_4,

		.csd = QT1050_CSD_4,

	}

};

static bool qt1050_volatile_reg(struct device *dev, unsigned int reg)

{

	switch (reg) {

	case QT1050_DET_STATUS:

	case QT1050_KEY_STATUS:

	case QT1050_KEY_SIGNAL_0_MSB:

	case QT1050_KEY_SIGNAL_0_LSB:

	case QT1050_KEY_SIGNAL_1_MSB:

	case QT1050_KEY_SIGNAL_1_LSB:

	case QT1050_KEY_SIGNAL_2_MSB:

	case QT1050_KEY_SIGNAL_2_LSB:

	case QT1050_KEY_SIGNAL_3_MSB:

	case QT1050_KEY_SIGNAL_3_LSB:

	case QT1050_KEY_SIGNAL_4_MSB:

	case QT1050_KEY_SIGNAL_4_LSB:

		return true;

	default:

		return false;

	}

}

static const struct regmap_range qt1050_readable_ranges[] = {

	regmap_reg_range(QT1050_CHIP_ID, QT1050_KEY_STATUS),

	regmap_reg_range(QT1050_KEY_SIGNAL_0_MSB, QT1050_KEY_SIGNAL_1_LSB),

	regmap_reg_range(QT1050_KEY_SIGNAL_2_MSB, QT1050_KEY_SIGNAL_4_LSB),

	regmap_reg_range(QT1050_REF_DATA_0_MSB, QT1050_REF_DATA_1_LSB),

	regmap_reg_range(QT1050_REF_DATA_2_MSB, QT1050_REF_DATA_4_LSB),

	regmap_reg_range(QT1050_NTHR_0, QT1050_NTHR_1),

	regmap_reg_range(QT1050_NTHR_2, QT1050_NTHR_4),

	regmap_reg_range(QT1050_PULSE_SCALE_0, QT1050_PULSE_SCALE_1),

	regmap_reg_range(QT1050_PULSE_SCALE_2, QT1050_PULSE_SCALE_4),

	regmap_reg_range(QT1050_DI_AKS_0, QT1050_DI_AKS_1),

	regmap_reg_range(QT1050_DI_AKS_2, QT1050_DI_AKS_4),

	regmap_reg_range(QT1050_CSD_0, QT1050_CSD_1),

	regmap_reg_range(QT1050_CSD_2, QT1050_RES_CAL),

};

static const struct regmap_access_table qt1050_readable_table = {

	.yes_ranges = qt1050_readable_ranges,

	.n_yes_ranges = ARRAY_SIZE(qt1050_readable_ranges),

};

static const struct regmap_range qt1050_writeable_ranges[] = {

	regmap_reg_range(QT1050_NTHR_0, QT1050_NTHR_1),

	regmap_reg_range(QT1050_NTHR_2, QT1050_NTHR_4),

	regmap_reg_range(QT1050_PULSE_SCALE_0, QT1050_PULSE_SCALE_1),

	regmap_reg_range(QT1050_PULSE_SCALE_2, QT1050_PULSE_SCALE_4),

	regmap_reg_range(QT1050_DI_AKS_0, QT1050_DI_AKS_1),

	regmap_reg_range(QT1050_DI_AKS_2, QT1050_DI_AKS_4),

	regmap_reg_range(QT1050_CSD_0, QT1050_CSD_1),

	regmap_reg_range(QT1050_CSD_2, QT1050_RES_CAL),

};

static const struct regmap_access_table qt1050_writeable_table = {

	.yes_ranges = qt1050_writeable_ranges,

	.n_yes_ranges = ARRAY_SIZE(qt1050_writeable_ranges),

};

static struct regmap_config qt1050_regmap_config = {

	.reg_bits = 8,

	.val_bits = 8,

	.max_register = QT1050_RES_CAL,

	.cache_type = REGCACHE_RBTREE,

	.wr_table = &qt1050_writeable_table,

	.rd_table = &qt1050_readable_table,

	.volatile_reg = qt1050_volatile_reg,

};

static bool qt1050_identify(struct qt1050_priv *ts)

{

	unsigned int val;

	int err;

	/* Read Chip ID */

	regmap_read(ts->regmap, QT1050_CHIP_ID, &val);

	if (val != QT1050_CHIP_ID_VER) {

		dev_err(&ts->client->dev, "ID %d not supported\n", val);

		return false;

	}

	/* Read firmware version */

	err = regmap_read(ts->regmap, QT1050_FW_VERSION, &val);

	if (err) {

		dev_err(&ts->client->dev, "could not read the firmware version\n");

		return false;

	}

	dev_info(&ts->client->dev, "AT42QT1050 firmware version %1d.%1d\n",

		 val >> 4, val & 0xf);

	return true;

}

static irqreturn_t qt1050_irq_threaded(int irq, void *dev_id)

{

	struct qt1050_priv *ts = dev_id;

	struct input_dev *input = ts->input;

	unsigned long new_keys, changed;

	unsigned int val;

	int i, err;

	/* Read the detected status register, thus clearing interrupt */

	err = regmap_read(ts->regmap, QT1050_DET_STATUS, &val);

	if (err) {

		dev_err(&ts->client->dev, "Fail to read detection status: %d\n",

			err);

		return IRQ_NONE;

	}

	/* Read which key changed, keys are not continuous */

	err = regmap_read(ts->regmap, QT1050_KEY_STATUS, &val);

	if (err) {

		dev_err(&ts->client->dev,

			"Fail to determine the key status: %d\n", err);

		return IRQ_NONE;

	}

	new_keys = (val & 0x70) >> 2 | (val & 0x6) >> 1;

	changed = ts->last_keys ^ new_keys;

	/* Report registered keys only */

	changed &= ts->reg_keys;

	for_each_set_bit(i, &changed, QT1050_MAX_KEYS)

		input_report_key(input, ts->keys[i].keycode,

				 test_bit(i, &new_keys));

	ts->last_keys = new_keys;

	input_sync(input);

	return IRQ_HANDLED;

}

static const struct qt1050_key_regs *qt1050_get_key_regs(int key_num)

{

	return &qt1050_key_regs_data[key_num];

}

static int qt1050_set_key(struct regmap *map, int number, int on)

{

	const struct qt1050_key_regs *key_regs;

	key_regs = qt1050_get_key_regs(number);

	return regmap_update_bits(map, key_regs->di_aks, 0xfc,

				  on ? BIT(4) : 0x00);

}

static int qt1050_apply_fw_data(struct qt1050_priv *ts)

{

	struct regmap *map = ts->regmap;

	struct qt1050_key *button = &ts->keys[0];

	const struct qt1050_key_regs *key_regs;

	int i, err;

	/* Disable all keys and enable only the specified ones */

	for (i = 0; i < QT1050_MAX_KEYS; i++) {

		err = qt1050_set_key(map, i, 0);

		if (err)

			return err;

	}

	for (i = 0; i < QT1050_MAX_KEYS; i++, button++) {

		/* Keep KEY_RESERVED keys off */

		if (button->keycode == KEY_RESERVED)

			continue;

		err = qt1050_set_key(map, button->num, 1);

		if (err)

			return err;

		key_regs = qt1050_get_key_regs(button->num);

		err = regmap_write(map, key_regs->pulse_scale,

				   (button->samples << 4) | (button->scale));

		if (err)

			return err;

		err = regmap_write(map, key_regs->csd, button->charge_delay);

		if (err)

			return err;

		err = regmap_write(map, key_regs->nthr, button->thr_cnt);

		if (err)

			return err;

	}

	return 0;

}

static int qt1050_parse_fw(struct qt1050_priv *ts)

{

	struct device *dev = &ts->client->dev;

	struct fwnode_handle *child;

	int nbuttons;

	nbuttons = device_get_child_node_count(dev);

	if (nbuttons == 0 || nbuttons > QT1050_MAX_KEYS)

		return -ENODEV;

	device_for_each_child_node(dev, child) {

		struct qt1050_key button;

		/* Required properties */

		if (fwnode_property_read_u32(child, "linux,code",

					     &button.keycode)) {

			dev_err(dev, "Button without keycode\n");

			goto err;

		}

		if (button.keycode >= KEY_MAX) {

			dev_err(dev, "Invalid keycode 0x%x\n",

				button.keycode);

			goto err;

		}

		if (fwnode_property_read_u32(child, "reg",

					     &button.num)) {

			dev_err(dev, "Button without pad number\n");

			goto err;

		}

		if (button.num < 0 || button.num > QT1050_MAX_KEYS - 1)

			goto err;

		ts->reg_keys |= BIT(button.num);

		/* Optional properties */

		if (fwnode_property_read_u32(child,

					     "microchip,pre-charge-time-ns",

					     &button.charge_delay)) {

			button.charge_delay = 0;

		} else {

			if (button.charge_delay % 2500 == 0)

				button.charge_delay =

					button.charge_delay / 2500;

			else

				button.charge_delay = 0;

		}

		if (fwnode_property_read_u32(child, "microchip,average-samples",

					 &button.samples)) {

			button.samples = 0;

		} else {

			if (is_power_of_2(button.samples))

				button.samples = ilog2(button.samples);

			else

				button.samples = 0;

		}

		if (fwnode_property_read_u32(child, "microchip,average-scaling",

					     &button.scale)) {

			button.scale = 0;

		} else {

			if (is_power_of_2(button.scale))

				button.scale = ilog2(button.scale);

			else

				button.scale = 0;

		}

		if (fwnode_property_read_u32(child, "microchip,threshold",

					 &button.thr_cnt)) {

			button.thr_cnt = 20;

		} else {

			if (button.thr_cnt > 255)

				button.thr_cnt = 20;

		}

		ts->keys[button.num] = button;

	}

	return 0;

err:

	fwnode_handle_put(child);

	return -EINVAL;

}

static int qt1050_probe(struct i2c_client *client)

{

	struct qt1050_priv *ts;

	struct input_dev *input;

	struct device *dev = &client->dev;

	struct regmap *map;

	unsigned int status, i;

	int err;

	/* Check basic functionality */

	err = i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE);

	if (!err) {

		dev_err(&client->dev, "%s adapter not supported\n",

			dev_driver_string(&client->adapter->dev));

		return -ENODEV;

	}

	if (!client->irq) {

		dev_err(dev, "assign a irq line to this device\n");

		return -EINVAL;

	}

	ts = devm_kzalloc(dev, sizeof(*ts), GFP_KERNEL);

	if (!ts)

		return -ENOMEM;

	input = devm_input_allocate_device(dev);

	if (!input)

		return -ENOMEM;

	map = devm_regmap_init_i2c(client, &qt1050_regmap_config);

	if (IS_ERR(map))

		return PTR_ERR(map);

	ts->client = client;

	ts->input = input;

	ts->regmap = map;

	i2c_set_clientdata(client, ts);

	/* Identify the qt1050 chip */

	if (!qt1050_identify(ts))

		return -ENODEV;

	/* Get pdata */

	err = qt1050_parse_fw(ts);

	if (err) {

		dev_err(dev, "Failed to parse firmware: %d\n", err);

		return err;

	}

	input->name = "AT42QT1050 QTouch Sensor";

	input->dev.parent = &client->dev;

	input->id.bustype = BUS_I2C;

	/* Add the keycode */

	input->keycode = ts->keycodes;

	input->keycodesize = sizeof(ts->keycodes[0]);

	input->keycodemax = QT1050_MAX_KEYS;

	__set_bit(EV_KEY, input->evbit);

	for (i = 0; i < QT1050_MAX_KEYS; i++) {

		ts->keycodes[i] = ts->keys[i].keycode;

		__set_bit(ts->keycodes[i], input->keybit);

	}

	/* Trigger re-calibration */

	err = regmap_update_bits(ts->regmap, QT1050_RES_CAL, 0x7f,

				 QT1050_RES_CAL_CALIBRATE);

	if (err) {

		dev_err(dev, "Trigger calibration failed: %d\n", err);

		return err;

	}

	err = regmap_read_poll_timeout(ts->regmap, QT1050_DET_STATUS, status,

				 status >> 7 == 1, 10000, 200000);

	if (err) {

		dev_err(dev, "Calibration failed: %d\n", err);

		return err;

	}

	/* Soft reset to set defaults */

	err = regmap_update_bits(ts->regmap, QT1050_RES_CAL,

				 QT1050_RES_CAL_RESET, QT1050_RES_CAL_RESET);

	if (err) {

		dev_err(dev, "Trigger soft reset failed: %d\n", err);

		return err;

	}

	msleep(QT1050_RESET_TIME);

	/* Set pdata */

	err = qt1050_apply_fw_data(ts);

	if (err) {

		dev_err(dev, "Failed to set firmware data: %d\n", err);

		return err;

	}

	err = devm_request_threaded_irq(dev, client->irq, NULL,

					qt1050_irq_threaded, IRQF_ONESHOT,

					"qt1050", ts);

	if (err) {

		dev_err(&client->dev, "Failed to request irq: %d\n", err);

		return err;

	}

	/* Clear #CHANGE line */

	err = regmap_read(ts->regmap, QT1050_DET_STATUS, &status);

	if (err) {

		dev_err(dev, "Failed to clear #CHANGE line level: %d\n", err);

		return err;

	}

	/* Register the input device */

	err = input_register_device(ts->input);

	if (err) {

		dev_err(&client->dev, "Failed to register input device: %d\n",

			err);

		return err;

	}

	return 0;

}

static int __maybe_unused qt1050_suspend(struct device *dev)

{

	struct i2c_client *client = to_i2c_client(dev);

	struct qt1050_priv *ts = i2c_get_clientdata(client);

	disable_irq(client->irq);

	/*

	 * Set measurement interval to 1s (125 x 8ms) if wakeup is allowed

	 * else turn off. The 1s interval seems to be a good compromise between

	 * low power and response time.

	 */

	return regmap_write(ts->regmap, QT1050_LPMODE,

			    device_may_wakeup(dev) ? 125 : 0);

}

static int __maybe_unused qt1050_resume(struct device *dev)

{

	struct i2c_client *client = to_i2c_client(dev);

	struct qt1050_priv *ts = i2c_get_clientdata(client);

	enable_irq(client->irq);

	/* Set measurement interval back to 16ms (2 x 8ms) */

	return regmap_write(ts->regmap, QT1050_LPMODE, 2);

}

static SIMPLE_DEV_PM_OPS(qt1050_pm_ops, qt1050_suspend, qt1050_resume);

static const struct of_device_id __maybe_unused qt1050_of_match[] = {

	{ .compatible = "microchip,qt1050", },

	{ },

};

MODULE_DEVICE_TABLE(of, qt1050_of_match);

static struct i2c_driver qt1050_driver = {

	.driver	= {

		.name = "qt1050",

		.of_match_table = of_match_ptr(qt1050_of_match),

		.pm = &qt1050_pm_ops,

	},

	.probe_new = qt1050_probe,

};

module_i2c_driver(qt1050_driver);

MODULE_AUTHOR("Marco Felsch <kernel@pengutronix.de");

MODULE_DESCRIPTION("Driver for AT42QT1050 QTouch sensor");

MODULE_LICENSE("GPL v2");