Re: [PATCH] Input: qt1050 - add Microchip AT42QT1050 support

[Dmitry Torokhov <dmitry.torokhov@gmail.com>]

Hi Marco,

On Mon, Sep 24, 2018 at 05:13:30PM +0200, Marco Felsch wrote:
> Add initial support for the AT42QT1050 (QT1050) device. The device
> supports up to five input keys, dependent on the mode. Since it adds only
> the initial support the "1 to 4 keys plus Guard Channel" mode isn't
> support.
> 
> Signed-off-by: Marco Felsch <m.felsch@pengutronix.de>
> ---
>  .../bindings/input/microchip,qt1050.txt       |  54 ++
>  drivers/input/keyboard/Kconfig                |  11 +
>  drivers/input/keyboard/Makefile               |   1 +
>  drivers/input/keyboard/qt1050.c               | 589 ++++++++++++++++++
>  4 files changed, 655 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/input/microchip,qt1050.txt
>  create mode 100644 drivers/input/keyboard/qt1050.c
> 
> diff --git a/Documentation/devicetree/bindings/input/microchip,qt1050.txt b/Documentation/devicetree/bindings/input/microchip,qt1050.txt
> new file mode 100644
> index 000000000000..d63e286f6526
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/input/microchip,qt1050.txt
> @@ -0,0 +1,54 @@
> +Microchip AT42QT1050 Five-channel Touch Sensor IC
> +
> +The AT42QT1050 (QT1050) is a QTouchADC sensor driver. 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 touchkeys
> +- interrupts: The sink for the touchpad's IRQ output,
> +  see ../interrupt-controller/interrupts.txt
> +- linux,keycodes: Specifies an array of numeric keycode values to be used for
> +  reporting button presses. The array can contain up to 5 entries. Array index
> +  0 correspond to key 0 and so on. If the keys aren't continuous the
> +  KEY_RESERVED must be used. Keys marked as KEY_RESERVED or not specified will
> +  be disabled.
> +
> +Optional properties:
> +- pre-charge-time: Specifies an array of precharge times in ns for each touch
> +  pad. The value for each pad depend on the hardware layouts. If not specified
> +  or invalid values are specified the default value is taken.
> +  Valid value range [ns]: 0 - 637500; values must be a multiple of 2500;
> +  default is 0.
> +- touchscreen-average-samples: Please see ../input/touchscreen/touchscreen.txt
> +  for more information. Unlike the general binding, this is an array to specify
> +  the samples for each pad. If not specified or invalid values are specified
> +  the default value is taken.
> +  Valid values: 1, 4, 16, 64, 256, 1024, 4096, 16384; default is 1.
> +- touchscreen-pre-scaling: Please see ../input/touchscreen/touchscreen.txt for
> +  more information. Unlike the general binding, this is an array to specify the
> +  scaling factor for each pad. If not specified or invalid values are specified
> +  the default value is taken.
> +  Valid values: 1, 2, 4, 8, 16, 32, 64, 128; default is 1.
> +- touchscreen-fuzz-pressure: Please see ../input/touchscreen/touchscreen.txt for
> +  more information. Unlike the general binding, this is an array to specify the
> +  noise (threshold) value for each pad. If not specified or invalid values are
> +  specified the default value is taken.


I am confused why we refer to touchscreen bindings here... Yes, the
device is a capacitive touch sensor, but it it not a touchscreen
controller. I think referring to generic touchscreen binding is
confusing. Especially since they even do not map to the generic binding
(list vs scalar value).

> +  Valid value range: 0 - 255; default is 20.
> +
> +Example:
> +QT1050 with 3 non continuous key, key3 and key5 are disabled.
> +
> +touchkeys@41 {
> +	compatible = "microchip,qt1050";
> +	reg = <0x41>;
> +	interrupt-parent = <&gpio0>;
> +	interrupts = <17 IRQ_TYPE_EDGE_FALLING>;
> +	linux,keycodes = <KEY_UP>, <KEY_RIGHT>, <KEY_RESERVED>, <KEY_DOWN>;
> +	touchscreen-average-samples = <64>, <64>, <64>, <256>;
> +	touchscreen-pre-scaling = <16>, <8>, <16>, <16>;
> +};
> diff --git a/drivers/input/keyboard/Kconfig b/drivers/input/keyboard/Kconfig
> index 4713957b0cbb..08aba5e7cd93 100644
> --- a/drivers/input/keyboard/Kconfig
> +++ b/drivers/input/keyboard/Kconfig
> @@ -137,6 +137,17 @@ config KEYBOARD_ATKBD_RDI_KEYCODES
>  	  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
> diff --git a/drivers/input/keyboard/Makefile b/drivers/input/keyboard/Makefile
> index 182e92985dbf..f0291ca39f62 100644
> --- a/drivers/input/keyboard/Makefile
> +++ b/drivers/input/keyboard/Makefile
> @@ -50,6 +50,7 @@ obj-$(CONFIG_KEYBOARD_OPENCORES)	+= opencores-kbd.o
>  obj-$(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
> diff --git a/drivers/input/keyboard/qt1050.c b/drivers/input/keyboard/qt1050.c
> new file mode 100644
> index 000000000000..80415586955d
> --- /dev/null
> +++ b/drivers/input/keyboard/qt1050.c
> @@ -0,0 +1,589 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + *  Microchip AT42QT1050 QTouch Sensor Controller
> + *
> + *  Authors: 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 {
> +	u32 charge_delay;
> +	u32 thr_cnt;
> +	u32 samples;
> +	u32 scale;
> +	u16 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			last_keys;
> +};
> +
> +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;
> +
> +	/* 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 */
> +	regmap_read(ts->regmap, QT1050_FW_VERSION, &val);
> +	if (val < 0) {
> +		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;
> +
> +	for_each_set_bit(i, &changed, 8) {
> +		input_report_key(input, ts->keycodes[i],
> +				 test_bit(i, &new_keys));
> +	}
> +
> +	ts->last_keys = new_keys;
> +	input_sync(input);
> +
> +	return IRQ_HANDLED;
> +}
> +
> +static int qt1050_disable_key(struct regmap *map, int number)
> +{
> +	unsigned int reg;
> +
> +	switch (number) {
> +	case 0:
> +		reg = QT1050_DI_AKS_0;
> +		break;
> +	case 1:
> +		reg = QT1050_DI_AKS_1;
> +		break;
> +	case 2:
> +		reg = QT1050_DI_AKS_2;
> +		break;
> +	case 3:
> +		reg = QT1050_DI_AKS_3;
> +		break;
> +	case 4:
> +		reg = QT1050_DI_AKS_4;
> +		break;
> +	}
> +
> +	return regmap_update_bits(map, reg, 0xfc, 0x00);
> +}
> +
> +#ifdef CONFIG_OF
> +static int qt1050_set_dt_data(struct qt1050_priv *ts)
> +{
> +	struct regmap *map = ts->regmap;
> +	struct qt1050_key *k;
> +	int i, err;
> +	unsigned int pulsc_reg, csd_reg, nthr_reg;
> +
> +	for (i = 0; i < QT1050_MAX_KEYS; i++) {
> +		k = &ts->keys[i];
> +		/* disable all keys which are marked as KEY_RESERVED */
> +		if (k->keycode == KEY_RESERVED) {
> +			err = qt1050_disable_key(map, i);
> +			if (err)
> +				return err;
> +			continue;
> +		}
> +
> +		switch (i) {
> +		case 0:
> +			pulsc_reg = QT1050_PULSE_SCALE_0;
> +			csd_reg = QT1050_CSD_0;
> +			nthr_reg = QT1050_NTHR_0;
> +			break;
> +		case 1:
> +			pulsc_reg = QT1050_PULSE_SCALE_1;
> +			csd_reg = QT1050_CSD_1;
> +			nthr_reg = QT1050_NTHR_1;
> +			break;
> +		case 2:
> +			pulsc_reg = QT1050_PULSE_SCALE_1;
> +			csd_reg = QT1050_CSD_2;
> +			nthr_reg = QT1050_NTHR_2;
> +			break;
> +		case 3:
> +			pulsc_reg = QT1050_PULSE_SCALE_3;
> +			csd_reg = QT1050_CSD_3;
> +			nthr_reg = QT1050_NTHR_3;
> +			break;
> +		case 4:
> +			pulsc_reg = QT1050_PULSE_SCALE_4;
> +			csd_reg = QT1050_CSD_4;
> +			nthr_reg = QT1050_NTHR_4;
> +			break;
> +		}
> +
> +		err = regmap_write(map, pulsc_reg,
> +				   (k->samples << 4) | (k->scale));
> +		if (err)
> +			return err;
> +		err = regmap_write(map, csd_reg, k->charge_delay);
> +		if (err)
> +			return err;
> +		err = regmap_write(map, nthr_reg, k->thr_cnt);
> +		if (err)
> +			return err;
> +	}
> +
> +	return 0;
> +}
> +
> +static int qt1050_parse_dt(struct qt1050_priv *ts)
> +{
> +	struct device *dev = &ts->client->dev;
> +	struct device_node *node = dev->of_node;
> +	int ret, i, n_keys;
> +	u32 tmp[QT1050_MAX_KEYS];
> +
> +	ret = of_property_read_variable_u32_array(node, "linux,keycodes",
> +						  &tmp[0], 1,
> +						  QT1050_MAX_KEYS);
> +
> +	/*
> +	 * remaining keys are mapped to KEY_RESERVED in case of
> +	 * n_keys < QT1050_MAX_KEYS
> +	 */
> +	n_keys = ret;
> +	for (i = 0; i < n_keys; i++) {
> +		if (tmp[i] >= KEY_MAX) {
> +			dev_err(dev, "wrong keycode 0x%x\n", tmp[i]);
> +			return -EINVAL;
> +		}
> +		ts->keys[i].keycode = (u16)tmp[i];
> +	}
> +
> +	ret = of_property_read_variable_u32_array(node, "pre-charge-time",
> +						  &tmp[0], 1, QT1050_MAX_KEYS);
> +	if (!IS_ERR_VALUE(ret)) {
> +		for (i = 0; i < QT1050_MAX_KEYS; i++) {
> +			if (i < n_keys && (tmp[i] % 2500 == 0))
> +				ts->keys[i].charge_delay = tmp[i] / 2500;
> +			else
> +				ts->keys[i].charge_delay = 0;
> +		}
> +	}
> +
> +	ret = of_property_read_variable_u32_array(node,
> +						  "touchscreen-average-samples",
> +						  &tmp[0], 1, QT1050_MAX_KEYS);
> +	if (!IS_ERR_VALUE(ret)) {
> +		for (i = 0; i < QT1050_MAX_KEYS; i++) {
> +			if (i < n_keys && is_power_of_2(tmp[i]))
> +				ts->keys[i].samples = ilog2(tmp[i]);
> +			else
> +				ts->keys[i].samples = 0;
> +		}
> +	}
> +
> +	ret = of_property_read_variable_u32_array(node,
> +						  "touchscreen-pre-scaling",
> +						  &tmp[0], 1, QT1050_MAX_KEYS);
> +	if (!IS_ERR_VALUE(ret)) {
> +		for (i = 0; i < QT1050_MAX_KEYS; i++) {
> +			if (i < n_keys && is_power_of_2(tmp[i]))
> +				ts->keys[i].scale = ilog2(tmp[i]);
> +			else
> +				ts->keys[i].scale = 0;
> +		}
> +	}
> +
> +	ret = of_property_read_variable_u32_array(node,
> +						  "touchscreen-fuzz-pressure",
> +						  &tmp[0], 1, QT1050_MAX_KEYS);
> +	if (!IS_ERR_VALUE(ret))
> +		for (i = 0; i < QT1050_MAX_KEYS; i++)
> +			ts->keys[i].thr_cnt = i < n_keys ? tmp[i] : 20;
> +
> +	return 0;
> +}
> +#endif
> +
> +static int qt1050_probe(struct i2c_client *client,
> +				const struct i2c_device_id *id)
> +{
> +	struct qt1050_priv *ts;
> +	struct input_dev *input;
> +	struct device *dev = &client->dev;
> +	struct regmap *map;
> +	unsigned int status;
> +	int 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);
> +	input = devm_input_allocate_device(dev);
> +	if (!ts || !input) {
> +		dev_err(dev, "insufficient memory\n");
> +		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;
> +
> +	if (IS_ENABLED(CONFIG_OF)) {
> +		err = qt1050_parse_dt(ts);
> +		if (err) {
> +			dev_err(dev, "Failed to parse dt: %d\n", err);
> +			return err;
> +		}
> +	} else {
> +		/* init each key with a valid code */
> +		for (i = 0; i < QT1050_MAX_KEYS; i++)
> +			ts->keys[i].keycode = KEY_1 + i;
> +	}

I'd rather we used generic device properties (i.e.
device_property_read_xxx() instead of of_property_read_xxx()) and did
not provide this fallback.

> +
> +	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 dt specified data */
> +	if (IS_ENABLED(CONFIG_OF)) {
> +		err = qt1050_set_dt_data(ts);
> +		if (err) {
> +			dev_err(dev, "Failed to set dt data: %d\n", err);
> +			return err;
> +		}
> +	}
> +
> +	err = devm_request_threaded_irq(dev, client->irq, NULL,
> +					qt1050_irq_threaded,
> +					IRQF_TRIGGER_NONE | 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);
> +
> +	if (device_may_wakeup(dev))
> +		enable_irq_wake(client->irq);
> +
> +	return regmap_write(ts->regmap, QT1050_LPMODE, 0x00);
> +}
> +
> +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);
> +
> +	if (device_may_wakeup(dev))
> +		disable_irq_wake(client->irq);
> +
> +	enable_irq(client->irq);
> +
> +	return regmap_write(ts->regmap, QT1050_LPMODE, 0x02);
> +}
> +
> +static SIMPLE_DEV_PM_OPS(qt1050_pm_ops, qt1050_suspend, qt1050_resume);
> +
> +static const struct i2c_device_id qt1050_id[] = {
> +	{ "qt1050", 0 },
> +	{ },
> +};
> +MODULE_DEVICE_TABLE(i2c, qt1050_id);
> +
> +#ifdef CONFIG_OF
> +static const struct of_device_id qt1050_of_match[] = {
> +	{ .compatible = "microchip,qt1050", },
> +	{ },
> +};
> +MODULE_DEVICE_TABLE(of, qt1050_of_match);
> +#endif
> +
> +static struct i2c_driver qt1050_driver = {
> +	.driver	= {
> +		.name	= "qt1050",
> +		.of_match_table = of_match_ptr(qt1050_of_match),
> +		.pm = &qt1050_pm_ops,
> +	},
> +	.probe		= qt1050_probe,
> +	.id_table	= qt1050_id,
> +};
> +
> +module_i2c_driver(qt1050_driver);
> +
> +MODULE_AUTHOR("Marco Felsch <kernel@pengutronix.de");
> +MODULE_DESCRIPTION("Driver for AT42QT1050 QTouch sensor");
> +MODULE_LICENSE("GPL");
> -- 
> 2.19.0
> 

Thanks.

-- 
Dmitry