[mirror_ubuntu-bionic-kernel.git] / drivers / input / misc / atmel_captouch.c

/*
 * Atmel Atmegaxx Capacitive Touch Button Driver
 *
 * Copyright (C) 2016 Google, inc.
 *
 * This software is licensed under the terms of the GNU General Public
 * License version 2, as published by the Free Software Foundation, and
 * may be copied, distributed, and modified under those terms.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

/*
 * It's irrelevant that the HW used to develop captouch driver is based
 * on Atmega88PA part and uses QtouchADC parts for sensing touch.
 * Calling this driver "captouch" is an arbitrary way to distinguish
 * the protocol this driver supported by other atmel/qtouch drivers.
 *
 * Captouch driver supports a newer/different version of the I2C
 * registers/commands than the qt1070.c driver.
 * Don't let the similarity of the general driver structure fool you.
 *
 * For raw i2c access from userspace, use i2cset/i2cget
 * to poke at /dev/i2c-N devices.
 */

#include <linux/device.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/i2c.h>
#include <linux/input.h>
#include <linux/interrupt.h>
#include <linux/slab.h>

/* Maximum number of buttons supported */
#define MAX_NUM_OF_BUTTONS		8

/* Registers */
#define REG_KEY1_THRESHOLD		0x02
#define REG_KEY2_THRESHOLD		0x03
#define REG_KEY3_THRESHOLD		0x04
#define REG_KEY4_THRESHOLD		0x05

#define REG_KEY1_REF_H			0x20
#define REG_KEY1_REF_L			0x21
#define REG_KEY2_REF_H			0x22
#define REG_KEY2_REF_L			0x23
#define REG_KEY3_REF_H			0x24
#define REG_KEY3_REF_L			0x25
#define REG_KEY4_REF_H			0x26
#define REG_KEY4_REF_L			0x27

#define REG_KEY1_DLT_H			0x30
#define REG_KEY1_DLT_L			0x31
#define REG_KEY2_DLT_H			0x32
#define REG_KEY2_DLT_L			0x33
#define REG_KEY3_DLT_H			0x34
#define REG_KEY3_DLT_L			0x35
#define REG_KEY4_DLT_H			0x36
#define REG_KEY4_DLT_L			0x37

#define REG_KEY_STATE			0x3C

/*
 * @i2c_client: I2C slave device client pointer
 * @input: Input device pointer
 * @num_btn: Number of buttons
 * @keycodes: map of button# to KeyCode
 * @prev_btn: Previous key state to detect button "press" or "release"
 * @xfer_buf: I2C transfer buffer
 */
struct atmel_captouch_device {
	struct i2c_client *client;
	struct input_dev *input;
	u32 num_btn;
	u32 keycodes[MAX_NUM_OF_BUTTONS];
	u8 prev_btn;
	u8 xfer_buf[8] ____cacheline_aligned;
};

/*
 * Read from I2C slave device
 * The protocol is that the client has to provide both the register address
 * and the length, and while reading back the device would prepend the data
 * with address and length for verification.
 */
static int atmel_read(struct atmel_captouch_device *capdev,
			 u8 reg, u8 *data, size_t len)
{
	struct i2c_client *client = capdev->client;
	struct device *dev = &client->dev;
	struct i2c_msg msg[2];
	int err;

	if (len > sizeof(capdev->xfer_buf) - 2)
		return -EINVAL;

	capdev->xfer_buf[0] = reg;
	capdev->xfer_buf[1] = len;

	msg[0].addr = client->addr;
	msg[0].flags = 0;
	msg[0].buf = capdev->xfer_buf;
	msg[0].len = 2;

	msg[1].addr = client->addr;
	msg[1].flags = I2C_M_RD;
	msg[1].buf = capdev->xfer_buf;
	msg[1].len = len + 2;

	err = i2c_transfer(client->adapter, msg, ARRAY_SIZE(msg));
	if (err != ARRAY_SIZE(msg))
		return err < 0 ? err : -EIO;

	if (capdev->xfer_buf[0] != reg) {
		dev_err(dev,
			"I2C read error: register address does not match (%#02x vs %02x)\n",
			capdev->xfer_buf[0], reg);
		return -ECOMM;
	}

	memcpy(data, &capdev->xfer_buf[2], len);

	return 0;
}

/*
 * Handle interrupt and report the key changes to the input system.
 * Multi-touch can be supported; however, it really depends on whether
 * the device can multi-touch.
 */
static irqreturn_t atmel_captouch_isr(int irq, void *data)
{
	struct atmel_captouch_device *capdev = data;
	struct device *dev = &capdev->client->dev;
	int error;
	int i;
	u8 new_btn;
	u8 changed_btn;

	error = atmel_read(capdev, REG_KEY_STATE, &new_btn, 1);
	if (error) {
		dev_err(dev, "failed to read button state: %d\n", error);
		goto out;
	}

	dev_dbg(dev, "%s: button state %#02x\n", __func__, new_btn);

	changed_btn = new_btn ^ capdev->prev_btn;
	capdev->prev_btn = new_btn;

	for (i = 0; i < capdev->num_btn; i++) {
		if (changed_btn & BIT(i))
			input_report_key(capdev->input,
					 capdev->keycodes[i],
					 new_btn & BIT(i));
	}

	input_sync(capdev->input);

out:
	return IRQ_HANDLED;
}

/*
 * Probe function to setup the device, input system and interrupt
 */
static int atmel_captouch_probe(struct i2c_client *client,
		const struct i2c_device_id *id)
{
	struct atmel_captouch_device *capdev;
	struct device *dev = &client->dev;
	struct device_node *node;
	int i;
	int err;

	if (!i2c_check_functionality(client->adapter,
				     I2C_FUNC_SMBUS_BYTE_DATA |
					I2C_FUNC_SMBUS_WORD_DATA |
					I2C_FUNC_SMBUS_I2C_BLOCK)) {
		dev_err(dev, "needed i2c functionality is not supported\n");
		return -EINVAL;
	}

	capdev = devm_kzalloc(dev, sizeof(*capdev), GFP_KERNEL);
	if (!capdev)
		return -ENOMEM;

	capdev->client = client;

	err = atmel_read(capdev, REG_KEY_STATE,
			    &capdev->prev_btn, sizeof(capdev->prev_btn));
	if (err) {
		dev_err(dev, "failed to read initial button state: %d\n", err);
		return err;
	}

	capdev->input = devm_input_allocate_device(dev);
	if (!capdev->input) {
		dev_err(dev, "failed to allocate input device\n");
		return -ENOMEM;
	}

	capdev->input->id.bustype = BUS_I2C;
	capdev->input->id.product = 0x880A;
	capdev->input->id.version = 0;
	capdev->input->name = "ATMegaXX Capacitive Button Controller";
	__set_bit(EV_KEY, capdev->input->evbit);

	node = dev->of_node;
	if (!node) {
		dev_err(dev, "failed to find matching node in device tree\n");
		return -EINVAL;
	}

	if (of_property_read_bool(node, "autorepeat"))
		__set_bit(EV_REP, capdev->input->evbit);

	capdev->num_btn = of_property_count_u32_elems(node, "linux,keymap");
	if (capdev->num_btn > MAX_NUM_OF_BUTTONS)
		capdev->num_btn = MAX_NUM_OF_BUTTONS;

	err = of_property_read_u32_array(node, "linux,keycodes",
					 capdev->keycodes,
					 capdev->num_btn);
	if (err) {
		dev_err(dev,
			"failed to read linux,keycode property: %d\n", err);
		return err;
	}

	for (i = 0; i < capdev->num_btn; i++)
		__set_bit(capdev->keycodes[i], capdev->input->keybit);

	capdev->input->keycode = capdev->keycodes;
	capdev->input->keycodesize = sizeof(capdev->keycodes[0]);
	capdev->input->keycodemax = capdev->num_btn;

	err = input_register_device(capdev->input);
	if (err)
		return err;

	err = devm_request_threaded_irq(dev, client->irq,
					NULL, atmel_captouch_isr,
					IRQF_ONESHOT,
					"atmel_captouch", capdev);
	if (err) {
		dev_err(dev, "failed to request irq %d: %d\n",
			client->irq, err);
		return err;
	}

	return 0;
}

#ifdef CONFIG_OF
static const struct of_device_id atmel_captouch_of_id[] = {
	{
		.compatible = "atmel,captouch",
	},
	{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, atmel_captouch_of_id);
#endif

static const struct i2c_device_id atmel_captouch_id[] = {
	{ "atmel_captouch", 0 },
	{ }
};
MODULE_DEVICE_TABLE(i2c, atmel_captouch_id);

static struct i2c_driver atmel_captouch_driver = {
	.probe		= atmel_captouch_probe,
	.id_table	= atmel_captouch_id,
	.driver		= {
		.name	= "atmel_captouch",
		.of_match_table = of_match_ptr(atmel_captouch_of_id),
	},
};
module_i2c_driver(atmel_captouch_driver);

/* Module information */
MODULE_AUTHOR("Hung-yu Wu <hywu@google.com>");
MODULE_DESCRIPTION("Atmel ATmegaXX Capacitance Touch Sensor I2C Driver");
MODULE_LICENSE("GPL v2");
Commit	Line	Data
b06d43f7 DHW	1	/*
	2	* Atmel Atmegaxx Capacitive Touch Button Driver
	3	*
	4	* Copyright (C) 2016 Google, inc.
	5	*
	6	* This software is licensed under the terms of the GNU General Public
	7	* License version 2, as published by the Free Software Foundation, and
	8	* may be copied, distributed, and modified under those terms.
	9	*
	10	* This program is distributed in the hope that it will be useful,
	11	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	12	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	13	* GNU General Public License for more details.
	14	*/
	15
	16	/*
	17	* It's irrelevant that the HW used to develop captouch driver is based
	18	* on Atmega88PA part and uses QtouchADC parts for sensing touch.
	19	* Calling this driver "captouch" is an arbitrary way to distinguish
	20	* the protocol this driver supported by other atmel/qtouch drivers.
	21	*
	22	* Captouch driver supports a newer/different version of the I2C
	23	* registers/commands than the qt1070.c driver.
	24	* Don't let the similarity of the general driver structure fool you.
	25	*
	26	* For raw i2c access from userspace, use i2cset/i2cget
	27	* to poke at /dev/i2c-N devices.
	28	*/
	29
	30	#include <linux/device.h>
	31	#include <linux/kernel.h>
	32	#include <linux/module.h>
	33	#include <linux/init.h>
	34	#include <linux/i2c.h>
	35	#include <linux/input.h>
	36	#include <linux/interrupt.h>
	37	#include <linux/slab.h>
	38
	39	/* Maximum number of buttons supported */
	40	#define MAX_NUM_OF_BUTTONS 8
	41
	42	/* Registers */
	43	#define REG_KEY1_THRESHOLD 0x02
	44	#define REG_KEY2_THRESHOLD 0x03
	45	#define REG_KEY3_THRESHOLD 0x04
	46	#define REG_KEY4_THRESHOLD 0x05
	47
	48	#define REG_KEY1_REF_H 0x20
	49	#define REG_KEY1_REF_L 0x21
	50	#define REG_KEY2_REF_H 0x22
	51	#define REG_KEY2_REF_L 0x23
	52	#define REG_KEY3_REF_H 0x24
	53	#define REG_KEY3_REF_L 0x25
	54	#define REG_KEY4_REF_H 0x26
	55	#define REG_KEY4_REF_L 0x27
	56
	57	#define REG_KEY1_DLT_H 0x30
	58	#define REG_KEY1_DLT_L 0x31
	59	#define REG_KEY2_DLT_H 0x32
	60	#define REG_KEY2_DLT_L 0x33
	61	#define REG_KEY3_DLT_H 0x34
	62	#define REG_KEY3_DLT_L 0x35
	63	#define REG_KEY4_DLT_H 0x36
	64	#define REG_KEY4_DLT_L 0x37
65
66	#define REG_KEY_STATE 0x3C
67
68	/*
69	* @i2c_client: I2C slave device client pointer
70	* @input: Input device pointer
71	* @num_btn: Number of buttons
72	* @keycodes: map of button# to KeyCode
73	* @prev_btn: Previous key state to detect button "press" or "release"
74	* @xfer_buf: I2C transfer buffer
75	*/
76	struct atmel_captouch_device {
77	struct i2c_client *client;
78	struct input_dev *input;
79	u32 num_btn;
80	u32 keycodes[MAX_NUM_OF_BUTTONS];
81	u8 prev_btn;
82	u8 xfer_buf[8] ____cacheline_aligned;
83	};
84
85	/*
86	* Read from I2C slave device
87	* The protocol is that the client has to provide both the register address
88	* and the length, and while reading back the device would prepend the data
89	* with address and length for verification.
90	*/
91	static int atmel_read(struct atmel_captouch_device *capdev,
92	u8 reg, u8 *data, size_t len)
93	{
94	struct i2c_client *client = capdev->client;
95	struct device *dev = &client->dev;
96	struct i2c_msg msg[2];
97	int err;
98
99	if (len > sizeof(capdev->xfer_buf) - 2)
100	return -EINVAL;
101
102	capdev->xfer_buf[0] = reg;
103	capdev->xfer_buf[1] = len;
104
105	msg[0].addr = client->addr;
106	msg[0].flags = 0;
107	msg[0].buf = capdev->xfer_buf;
108	msg[0].len = 2;
109
110	msg[1].addr = client->addr;
111	msg[1].flags = I2C_M_RD;
112	msg[1].buf = capdev->xfer_buf;
113	msg[1].len = len + 2;
114
115	err = i2c_transfer(client->adapter, msg, ARRAY_SIZE(msg));
116	if (err != ARRAY_SIZE(msg))
117	return err < 0 ? err : -EIO;
118
119	if (capdev->xfer_buf[0] != reg) {
120	dev_err(dev,
121	"I2C read error: register address does not match (%#02x vs %02x)\n",
122	capdev->xfer_buf[0], reg);
123	return -ECOMM;
124	}
125
126	memcpy(data, &capdev->xfer_buf[2], len);
127
128	return 0;
129	}
130
131	/*
132	* Handle interrupt and report the key changes to the input system.
133	* Multi-touch can be supported; however, it really depends on whether
134	* the device can multi-touch.
135	*/
136	static irqreturn_t atmel_captouch_isr(int irq, void *data)
137	{
138	struct atmel_captouch_device *capdev = data;
139	struct device *dev = &capdev->client->dev;
140	int error;
141	int i;
142	u8 new_btn;
143	u8 changed_btn;
144
145	error = atmel_read(capdev, REG_KEY_STATE, &new_btn, 1);
146	if (error) {
147	dev_err(dev, "failed to read button state: %d\n", error);
148	goto out;
149	}
150
151	dev_dbg(dev, "%s: button state %#02x\n", __func__, new_btn);
152
153	changed_btn = new_btn ^ capdev->prev_btn;
154	capdev->prev_btn = new_btn;
155
156	for (i = 0; i < capdev->num_btn; i++) {
157	if (changed_btn & BIT(i))
158	input_report_key(capdev->input,
159	capdev->keycodes[i],
160	new_btn & BIT(i));
161	}
162
163	input_sync(capdev->input);
164
165	out:
166	return IRQ_HANDLED;
167	}
168
169	/*
170	* Probe function to setup the device, input system and interrupt
171	*/
172	static int atmel_captouch_probe(struct i2c_client *client,
173	const struct i2c_device_id *id)
174	{
175	struct atmel_captouch_device *capdev;
176	struct device *dev = &client->dev;
177	struct device_node *node;
178	int i;
179	int err;
180
181	if (!i2c_check_functionality(client->adapter,
182	I2C_FUNC_SMBUS_BYTE_DATA \|
183	I2C_FUNC_SMBUS_WORD_DATA \|
184	I2C_FUNC_SMBUS_I2C_BLOCK)) {
185	dev_err(dev, "needed i2c functionality is not supported\n");
186	return -EINVAL;
187	}
188
189	capdev = devm_kzalloc(dev, sizeof(*capdev), GFP_KERNEL);
190	if (!capdev)
191	return -ENOMEM;
192
193	capdev->client = client;
b06d43f7 DHW	194
	195	err = atmel_read(capdev, REG_KEY_STATE,
	196	&capdev->prev_btn, sizeof(capdev->prev_btn));
	197	if (err) {
	198	dev_err(dev, "failed to read initial button state: %d\n", err);
	199	return err;
	200	}
	201
	202	capdev->input = devm_input_allocate_device(dev);
	203	if (!capdev->input) {
	204	dev_err(dev, "failed to allocate input device\n");
	205	return -ENOMEM;
	206	}
	207
	208	capdev->input->id.bustype = BUS_I2C;
	209	capdev->input->id.product = 0x880A;
	210	capdev->input->id.version = 0;
	211	capdev->input->name = "ATMegaXX Capacitive Button Controller";
	212	__set_bit(EV_KEY, capdev->input->evbit);
	213
	214	node = dev->of_node;
	215	if (!node) {
	216	dev_err(dev, "failed to find matching node in device tree\n");
	217	return -EINVAL;
	218	}
	219
	220	if (of_property_read_bool(node, "autorepeat"))
	221	__set_bit(EV_REP, capdev->input->evbit);
	222
	223	capdev->num_btn = of_property_count_u32_elems(node, "linux,keymap");
	224	if (capdev->num_btn > MAX_NUM_OF_BUTTONS)
	225	capdev->num_btn = MAX_NUM_OF_BUTTONS;
	226
	227	err = of_property_read_u32_array(node, "linux,keycodes",
	228	capdev->keycodes,
	229	capdev->num_btn);
	230	if (err) {
	231	dev_err(dev,
	232	"failed to read linux,keycode property: %d\n", err);
	233	return err;
	234	}
	235
	236	for (i = 0; i < capdev->num_btn; i++)
	237	__set_bit(capdev->keycodes[i], capdev->input->keybit);
	238
	239	capdev->input->keycode = capdev->keycodes;
	240	capdev->input->keycodesize = sizeof(capdev->keycodes[0]);
	241	capdev->input->keycodemax = capdev->num_btn;
	242
	243	err = input_register_device(capdev->input);
	244	if (err)
	245	return err;
	246
	247	err = devm_request_threaded_irq(dev, client->irq,
	248	NULL, atmel_captouch_isr,
	249	IRQF_ONESHOT,
	250	"atmel_captouch", capdev);
	251	if (err) {
	252	dev_err(dev, "failed to request irq %d: %d\n",
	253	client->irq, err);
	254	return err;
	255	}
	256
	257	return 0;
258	}
259
260	#ifdef CONFIG_OF
261	static const struct of_device_id atmel_captouch_of_id[] = {
262	{
263	.compatible = "atmel,captouch",
264	},
265	{ /* sentinel */ }
266	};
267	MODULE_DEVICE_TABLE(of, atmel_captouch_of_id);
268	#endif
269
270	static const struct i2c_device_id atmel_captouch_id[] = {
271	{ "atmel_captouch", 0 },
272	{ }
273	};
274	MODULE_DEVICE_TABLE(i2c, atmel_captouch_id);
275
276	static struct i2c_driver atmel_captouch_driver = {
277	.probe = atmel_captouch_probe,
278	.id_table = atmel_captouch_id,
279	.driver = {
280	.name = "atmel_captouch",
281	.of_match_table = of_match_ptr(atmel_captouch_of_id),
282	},
283	};
284	module_i2c_driver(atmel_captouch_driver);
285
286	/* Module information */
287	MODULE_AUTHOR("Hung-yu Wu <hywu@google.com>");
288	MODULE_DESCRIPTION("Atmel ATmegaXX Capacitance Touch Sensor I2C Driver");
289	MODULE_LICENSE("GPL v2");