cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
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s6sy761.c (13607B)


      1// SPDX-License-Identifier: GPL-2.0
      2// Samsung S6SY761 Touchscreen device driver
      3//
      4// Copyright (c) 2017 Samsung Electronics Co., Ltd.
      5// Copyright (c) 2017 Andi Shyti <andi@etezian.org>
      6
      7#include <asm/unaligned.h>
      8#include <linux/delay.h>
      9#include <linux/i2c.h>
     10#include <linux/input/mt.h>
     11#include <linux/input/touchscreen.h>
     12#include <linux/interrupt.h>
     13#include <linux/irq.h>
     14#include <linux/module.h>
     15#include <linux/pm_runtime.h>
     16#include <linux/regulator/consumer.h>
     17
     18/* commands */
     19#define S6SY761_SENSE_ON		0x10
     20#define S6SY761_SENSE_OFF		0x11
     21#define S6SY761_TOUCH_FUNCTION		0x30 /* R/W for get/set */
     22#define S6SY761_FIRMWARE_INTEGRITY	0x21
     23#define S6SY761_PANEL_INFO		0x23
     24#define S6SY761_DEVICE_ID		0x52
     25#define S6SY761_BOOT_STATUS		0x55
     26#define S6SY761_READ_ONE_EVENT		0x60
     27#define S6SY761_READ_ALL_EVENT		0x61
     28#define S6SY761_CLEAR_EVENT_STACK	0x62
     29#define S6SY761_APPLICATION_MODE	0xe4
     30
     31/* events */
     32#define S6SY761_EVENT_INFO		0x02
     33#define S6SY761_EVENT_VENDOR_INFO	0x07
     34
     35/* info */
     36#define S6SY761_INFO_BOOT_COMPLETE	0x00
     37
     38/* firmware status */
     39#define S6SY761_FW_OK			0x80
     40
     41/*
     42 * the functionalities are put as a reference
     43 * as in the device I am using none of them
     44 * works therefore not used in this driver yet.
     45 */
     46/* touchscreen functionalities */
     47#define S6SY761_MASK_TOUCH		BIT(0)
     48#define S6SY761_MASK_HOVER		BIT(1)
     49#define S6SY761_MASK_COVER		BIT(2)
     50#define S6SY761_MASK_GLOVE		BIT(3)
     51#define S6SY761_MASK_STYLUS		BIT(4)
     52#define S6SY761_MASK_PALM		BIT(5)
     53#define S6SY761_MASK_WET		BIT(6)
     54#define S6SY761_MASK_PROXIMITY		BIT(7)
     55
     56/* boot status (BS) */
     57#define S6SY761_BS_BOOT_LOADER		0x10
     58#define S6SY761_BS_APPLICATION		0x20
     59
     60/* event id */
     61#define S6SY761_EVENT_ID_COORDINATE	0x00
     62#define S6SY761_EVENT_ID_STATUS		0x01
     63
     64/* event register masks */
     65#define S6SY761_MASK_TOUCH_STATE	0xc0 /* byte 0 */
     66#define S6SY761_MASK_TID		0x3c
     67#define S6SY761_MASK_EID		0x03
     68#define S6SY761_MASK_X			0xf0 /* byte 3 */
     69#define S6SY761_MASK_Y			0x0f
     70#define S6SY761_MASK_Z			0x3f /* byte 6 */
     71#define S6SY761_MASK_LEFT_EVENTS	0x3f /* byte 7 */
     72#define S6SY761_MASK_TOUCH_TYPE		0xc0 /* MSB in byte 6, LSB in byte 7 */
     73
     74/* event touch state values */
     75#define S6SY761_TS_NONE			0x00
     76#define S6SY761_TS_PRESS		0x01
     77#define S6SY761_TS_MOVE			0x02
     78#define S6SY761_TS_RELEASE		0x03
     79
     80/* application modes */
     81#define S6SY761_APP_NORMAL		0x0
     82#define S6SY761_APP_LOW_POWER		0x1
     83#define S6SY761_APP_TEST		0x2
     84#define S6SY761_APP_FLASH		0x3
     85#define S6SY761_APP_SLEEP		0x4
     86
     87#define S6SY761_EVENT_SIZE		8
     88#define S6SY761_EVENT_COUNT		32
     89#define S6SY761_DEVID_SIZE		3
     90#define S6SY761_PANEL_ID_SIZE		11
     91#define S6SY761_TS_STATUS_SIZE		5
     92#define S6SY761_MAX_FINGERS		10
     93
     94#define S6SY761_DEV_NAME	"s6sy761"
     95
     96enum s6sy761_regulators {
     97	S6SY761_REGULATOR_VDD,
     98	S6SY761_REGULATOR_AVDD,
     99};
    100
    101struct s6sy761_data {
    102	struct i2c_client *client;
    103	struct regulator_bulk_data regulators[2];
    104	struct input_dev *input;
    105	struct touchscreen_properties prop;
    106
    107	u8 data[S6SY761_EVENT_SIZE * S6SY761_EVENT_COUNT];
    108
    109	u16 devid;
    110	u8 tx_channel;
    111};
    112
    113/*
    114 * We can't simply use i2c_smbus_read_i2c_block_data because we
    115 * need to read more than 255 bytes
    116 */
    117static int s6sy761_read_events(struct s6sy761_data *sdata, u16 n_events)
    118{
    119	u8 cmd = S6SY761_READ_ALL_EVENT;
    120	struct i2c_msg msgs[2] = {
    121		{
    122			.addr	= sdata->client->addr,
    123			.len	= 1,
    124			.buf	= &cmd,
    125		},
    126		{
    127			.addr	= sdata->client->addr,
    128			.flags	= I2C_M_RD,
    129			.len	= (n_events * S6SY761_EVENT_SIZE),
    130			.buf	= sdata->data + S6SY761_EVENT_SIZE,
    131		},
    132	};
    133	int ret;
    134
    135	ret = i2c_transfer(sdata->client->adapter, msgs, ARRAY_SIZE(msgs));
    136	if (ret < 0)
    137		return ret;
    138
    139	return ret == ARRAY_SIZE(msgs) ? 0 : -EIO;
    140}
    141
    142static void s6sy761_report_coordinates(struct s6sy761_data *sdata,
    143				       u8 *event, u8 tid)
    144{
    145	u8 major = event[4];
    146	u8 minor = event[5];
    147	u8 z = event[6] & S6SY761_MASK_Z;
    148	u16 x = (event[1] << 4) | ((event[3] & S6SY761_MASK_X) >> 4);
    149	u16 y = (event[2] << 4) | (event[3] & S6SY761_MASK_Y);
    150
    151	input_mt_slot(sdata->input, tid);
    152
    153	input_mt_report_slot_state(sdata->input, MT_TOOL_FINGER, true);
    154	input_report_abs(sdata->input, ABS_MT_POSITION_X, x);
    155	input_report_abs(sdata->input, ABS_MT_POSITION_Y, y);
    156	input_report_abs(sdata->input, ABS_MT_TOUCH_MAJOR, major);
    157	input_report_abs(sdata->input, ABS_MT_TOUCH_MINOR, minor);
    158	input_report_abs(sdata->input, ABS_MT_PRESSURE, z);
    159
    160	input_sync(sdata->input);
    161}
    162
    163static void s6sy761_report_release(struct s6sy761_data *sdata,
    164				   u8 *event, u8 tid)
    165{
    166	input_mt_slot(sdata->input, tid);
    167	input_mt_report_slot_state(sdata->input, MT_TOOL_FINGER, false);
    168
    169	input_sync(sdata->input);
    170}
    171
    172static void s6sy761_handle_coordinates(struct s6sy761_data *sdata, u8 *event)
    173{
    174	u8 tid;
    175	u8 touch_state;
    176
    177	if (unlikely(!(event[0] & S6SY761_MASK_TID)))
    178		return;
    179
    180	tid = ((event[0] & S6SY761_MASK_TID) >> 2) - 1;
    181	touch_state = (event[0] & S6SY761_MASK_TOUCH_STATE) >> 6;
    182
    183	switch (touch_state) {
    184
    185	case S6SY761_TS_NONE:
    186		break;
    187	case S6SY761_TS_RELEASE:
    188		s6sy761_report_release(sdata, event, tid);
    189		break;
    190	case S6SY761_TS_PRESS:
    191	case S6SY761_TS_MOVE:
    192		s6sy761_report_coordinates(sdata, event, tid);
    193		break;
    194	}
    195}
    196
    197static void s6sy761_handle_events(struct s6sy761_data *sdata, u8 n_events)
    198{
    199	int i;
    200
    201	for (i = 0; i < n_events; i++) {
    202		u8 *event = &sdata->data[i * S6SY761_EVENT_SIZE];
    203		u8 event_id = event[0] & S6SY761_MASK_EID;
    204
    205		if (!event[0])
    206			return;
    207
    208		switch (event_id) {
    209
    210		case S6SY761_EVENT_ID_COORDINATE:
    211			s6sy761_handle_coordinates(sdata, event);
    212			break;
    213
    214		case S6SY761_EVENT_ID_STATUS:
    215			break;
    216
    217		default:
    218			break;
    219		}
    220	}
    221}
    222
    223static irqreturn_t s6sy761_irq_handler(int irq, void *dev)
    224{
    225	struct s6sy761_data *sdata = dev;
    226	int ret;
    227	u8 n_events;
    228
    229	ret = i2c_smbus_read_i2c_block_data(sdata->client,
    230					    S6SY761_READ_ONE_EVENT,
    231					    S6SY761_EVENT_SIZE,
    232					    sdata->data);
    233	if (ret < 0) {
    234		dev_err(&sdata->client->dev, "failed to read events\n");
    235		return IRQ_HANDLED;
    236	}
    237
    238	if (!sdata->data[0])
    239		return IRQ_HANDLED;
    240
    241	n_events = sdata->data[7] & S6SY761_MASK_LEFT_EVENTS;
    242	if (unlikely(n_events > S6SY761_EVENT_COUNT - 1))
    243		return IRQ_HANDLED;
    244
    245	if (n_events) {
    246		ret = s6sy761_read_events(sdata, n_events);
    247		if (ret < 0) {
    248			dev_err(&sdata->client->dev, "failed to read events\n");
    249			return IRQ_HANDLED;
    250		}
    251	}
    252
    253	s6sy761_handle_events(sdata, n_events +  1);
    254
    255	return IRQ_HANDLED;
    256}
    257
    258static int s6sy761_input_open(struct input_dev *dev)
    259{
    260	struct s6sy761_data *sdata = input_get_drvdata(dev);
    261
    262	return i2c_smbus_write_byte(sdata->client, S6SY761_SENSE_ON);
    263}
    264
    265static void s6sy761_input_close(struct input_dev *dev)
    266{
    267	struct s6sy761_data *sdata = input_get_drvdata(dev);
    268	int ret;
    269
    270	ret = i2c_smbus_write_byte(sdata->client, S6SY761_SENSE_OFF);
    271	if (ret)
    272		dev_err(&sdata->client->dev, "failed to turn off sensing\n");
    273}
    274
    275static ssize_t s6sy761_sysfs_devid(struct device *dev,
    276				struct device_attribute *attr, char *buf)
    277{
    278	struct s6sy761_data *sdata = dev_get_drvdata(dev);
    279
    280	return sprintf(buf, "%#x\n", sdata->devid);
    281}
    282
    283static DEVICE_ATTR(devid, 0444, s6sy761_sysfs_devid, NULL);
    284
    285static struct attribute *s6sy761_sysfs_attrs[] = {
    286	&dev_attr_devid.attr,
    287	NULL
    288};
    289
    290static struct attribute_group s6sy761_attribute_group = {
    291	.attrs = s6sy761_sysfs_attrs
    292};
    293
    294static int s6sy761_power_on(struct s6sy761_data *sdata)
    295{
    296	u8 buffer[S6SY761_EVENT_SIZE];
    297	u8 event;
    298	int ret;
    299
    300	ret = regulator_bulk_enable(ARRAY_SIZE(sdata->regulators),
    301				    sdata->regulators);
    302	if (ret)
    303		return ret;
    304
    305	msleep(140);
    306
    307	/* double check whether the touch is functional */
    308	ret = i2c_smbus_read_i2c_block_data(sdata->client,
    309					    S6SY761_READ_ONE_EVENT,
    310					    S6SY761_EVENT_SIZE,
    311					    buffer);
    312	if (ret < 0)
    313		return ret;
    314
    315	event = (buffer[0] >> 2) & 0xf;
    316
    317	if ((event != S6SY761_EVENT_INFO &&
    318	     event != S6SY761_EVENT_VENDOR_INFO) ||
    319	    buffer[1] != S6SY761_INFO_BOOT_COMPLETE) {
    320		return -ENODEV;
    321	}
    322
    323	ret = i2c_smbus_read_byte_data(sdata->client, S6SY761_BOOT_STATUS);
    324	if (ret < 0)
    325		return ret;
    326
    327	/* for some reasons the device might be stuck in the bootloader */
    328	if (ret != S6SY761_BS_APPLICATION)
    329		return -ENODEV;
    330
    331	/* enable touch functionality */
    332	ret = i2c_smbus_write_word_data(sdata->client,
    333					S6SY761_TOUCH_FUNCTION,
    334					S6SY761_MASK_TOUCH);
    335	if (ret)
    336		return ret;
    337
    338	return 0;
    339}
    340
    341static int s6sy761_hw_init(struct s6sy761_data *sdata,
    342			   unsigned int *max_x, unsigned int *max_y)
    343{
    344	u8 buffer[S6SY761_PANEL_ID_SIZE]; /* larger read size */
    345	int ret;
    346
    347	ret = s6sy761_power_on(sdata);
    348	if (ret)
    349		return ret;
    350
    351	ret = i2c_smbus_read_i2c_block_data(sdata->client,
    352					    S6SY761_DEVICE_ID,
    353					    S6SY761_DEVID_SIZE,
    354					    buffer);
    355	if (ret < 0)
    356		return ret;
    357
    358	sdata->devid = get_unaligned_be16(buffer + 1);
    359
    360	ret = i2c_smbus_read_i2c_block_data(sdata->client,
    361					    S6SY761_PANEL_INFO,
    362					    S6SY761_PANEL_ID_SIZE,
    363					    buffer);
    364	if (ret < 0)
    365		return ret;
    366
    367	*max_x = get_unaligned_be16(buffer);
    368	*max_y = get_unaligned_be16(buffer + 2);
    369
    370	/* if no tx channels defined, at least keep one */
    371	sdata->tx_channel = max_t(u8, buffer[8], 1);
    372
    373	ret = i2c_smbus_read_byte_data(sdata->client,
    374				       S6SY761_FIRMWARE_INTEGRITY);
    375	if (ret < 0)
    376		return ret;
    377	else if (ret != S6SY761_FW_OK)
    378		return -ENODEV;
    379
    380	return 0;
    381}
    382
    383static void s6sy761_power_off(void *data)
    384{
    385	struct s6sy761_data *sdata = data;
    386
    387	disable_irq(sdata->client->irq);
    388	regulator_bulk_disable(ARRAY_SIZE(sdata->regulators),
    389						sdata->regulators);
    390}
    391
    392static int s6sy761_probe(struct i2c_client *client,
    393			 const struct i2c_device_id *id)
    394{
    395	struct s6sy761_data *sdata;
    396	unsigned int max_x, max_y;
    397	int err;
    398
    399	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C |
    400						I2C_FUNC_SMBUS_BYTE_DATA |
    401						I2C_FUNC_SMBUS_I2C_BLOCK))
    402		return -ENODEV;
    403
    404	sdata = devm_kzalloc(&client->dev, sizeof(*sdata), GFP_KERNEL);
    405	if (!sdata)
    406		return -ENOMEM;
    407
    408	i2c_set_clientdata(client, sdata);
    409	sdata->client = client;
    410
    411	sdata->regulators[S6SY761_REGULATOR_VDD].supply = "vdd";
    412	sdata->regulators[S6SY761_REGULATOR_AVDD].supply = "avdd";
    413	err = devm_regulator_bulk_get(&client->dev,
    414				      ARRAY_SIZE(sdata->regulators),
    415				      sdata->regulators);
    416	if (err)
    417		return err;
    418
    419	err = devm_add_action_or_reset(&client->dev, s6sy761_power_off, sdata);
    420	if (err)
    421		return err;
    422
    423	err = s6sy761_hw_init(sdata, &max_x, &max_y);
    424	if (err)
    425		return err;
    426
    427	sdata->input = devm_input_allocate_device(&client->dev);
    428	if (!sdata->input)
    429		return -ENOMEM;
    430
    431	sdata->input->name = S6SY761_DEV_NAME;
    432	sdata->input->id.bustype = BUS_I2C;
    433	sdata->input->open = s6sy761_input_open;
    434	sdata->input->close = s6sy761_input_close;
    435
    436	input_set_abs_params(sdata->input, ABS_MT_POSITION_X, 0, max_x, 0, 0);
    437	input_set_abs_params(sdata->input, ABS_MT_POSITION_Y, 0, max_y, 0, 0);
    438	input_set_abs_params(sdata->input, ABS_MT_TOUCH_MAJOR, 0, 255, 0, 0);
    439	input_set_abs_params(sdata->input, ABS_MT_TOUCH_MINOR, 0, 255, 0, 0);
    440	input_set_abs_params(sdata->input, ABS_MT_TOUCH_MAJOR, 0, 255, 0, 0);
    441	input_set_abs_params(sdata->input, ABS_MT_TOUCH_MINOR, 0, 255, 0, 0);
    442	input_set_abs_params(sdata->input, ABS_MT_PRESSURE, 0, 255, 0, 0);
    443
    444	touchscreen_parse_properties(sdata->input, true, &sdata->prop);
    445
    446	if (!input_abs_get_max(sdata->input, ABS_X) ||
    447	    !input_abs_get_max(sdata->input, ABS_Y)) {
    448		dev_warn(&client->dev, "the axis have not been set\n");
    449	}
    450
    451	err = input_mt_init_slots(sdata->input, sdata->tx_channel,
    452				  INPUT_MT_DIRECT);
    453	if (err)
    454		return err;
    455
    456	input_set_drvdata(sdata->input, sdata);
    457
    458	err = input_register_device(sdata->input);
    459	if (err)
    460		return err;
    461
    462	err = devm_request_threaded_irq(&client->dev, client->irq, NULL,
    463					s6sy761_irq_handler,
    464					IRQF_TRIGGER_LOW | IRQF_ONESHOT,
    465					"s6sy761_irq", sdata);
    466	if (err)
    467		return err;
    468
    469	err = devm_device_add_group(&client->dev, &s6sy761_attribute_group);
    470	if (err)
    471		return err;
    472
    473	pm_runtime_enable(&client->dev);
    474
    475	return 0;
    476}
    477
    478static int s6sy761_remove(struct i2c_client *client)
    479{
    480	pm_runtime_disable(&client->dev);
    481
    482	return 0;
    483}
    484
    485static int __maybe_unused s6sy761_runtime_suspend(struct device *dev)
    486{
    487	struct s6sy761_data *sdata = dev_get_drvdata(dev);
    488
    489	return i2c_smbus_write_byte_data(sdata->client,
    490				S6SY761_APPLICATION_MODE, S6SY761_APP_SLEEP);
    491}
    492
    493static int __maybe_unused s6sy761_runtime_resume(struct device *dev)
    494{
    495	struct s6sy761_data *sdata = dev_get_drvdata(dev);
    496
    497	return i2c_smbus_write_byte_data(sdata->client,
    498				S6SY761_APPLICATION_MODE, S6SY761_APP_NORMAL);
    499}
    500
    501static int __maybe_unused s6sy761_suspend(struct device *dev)
    502{
    503	struct s6sy761_data *sdata = dev_get_drvdata(dev);
    504
    505	s6sy761_power_off(sdata);
    506
    507	return 0;
    508}
    509
    510static int __maybe_unused s6sy761_resume(struct device *dev)
    511{
    512	struct s6sy761_data *sdata = dev_get_drvdata(dev);
    513
    514	enable_irq(sdata->client->irq);
    515
    516	return s6sy761_power_on(sdata);
    517}
    518
    519static const struct dev_pm_ops s6sy761_pm_ops = {
    520	SET_SYSTEM_SLEEP_PM_OPS(s6sy761_suspend, s6sy761_resume)
    521	SET_RUNTIME_PM_OPS(s6sy761_runtime_suspend,
    522				s6sy761_runtime_resume, NULL)
    523};
    524
    525#ifdef CONFIG_OF
    526static const struct of_device_id s6sy761_of_match[] = {
    527	{ .compatible = "samsung,s6sy761", },
    528	{ },
    529};
    530MODULE_DEVICE_TABLE(of, s6sy761_of_match);
    531#endif
    532
    533static const struct i2c_device_id s6sy761_id[] = {
    534	{ "s6sy761", 0 },
    535	{ },
    536};
    537MODULE_DEVICE_TABLE(i2c, s6sy761_id);
    538
    539static struct i2c_driver s6sy761_driver = {
    540	.driver = {
    541		.name = S6SY761_DEV_NAME,
    542		.of_match_table = of_match_ptr(s6sy761_of_match),
    543		.pm = &s6sy761_pm_ops,
    544	},
    545	.probe = s6sy761_probe,
    546	.remove = s6sy761_remove,
    547	.id_table = s6sy761_id,
    548};
    549
    550module_i2c_driver(s6sy761_driver);
    551
    552MODULE_AUTHOR("Andi Shyti <andi.shyti@samsung.com>");
    553MODULE_DESCRIPTION("Samsung S6SY761 Touch Screen");
    554MODULE_LICENSE("GPL v2");