/*
* Touch Screen driver for SiS 9200 family I2C Touch panels
*
* Copyright (C) 2015 SiS, Inc.
* Copyright (C) 2016 Nextfour Group
*
* 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.
*/
#include <linux/crc-itu-t.h>
#include <linux/delay.h>
#include <linux/i2c.h>
#include <linux/input.h>
#include <linux/input/mt.h>
#include <linux/interrupt.h>
#include <linux/gpio/consumer.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <asm/unaligned.h>
#define SIS_I2C_NAME "sis_i2c_ts"
/*
* The I2C packet format:
* le16 byte count
* u8 Report ID
* <contact data - variable length>
* u8 Number of contacts
* le16 Scan Time (optional)
* le16 CRC
*
* One touch point information consists of 6+ bytes, the order is:
* u8 contact state
* u8 finger id
* le16 x axis
* le16 y axis
* u8 contact width (optional)
* u8 contact height (optional)
* u8 pressure (optional)
*
* Maximum amount of data transmitted in one shot is 64 bytes, if controller
* needs to report more contacts than fit in one packet it will send true
* number of contacts in first packet and 0 as number of contacts in second
* packet.
*/
#define SIS_MAX_PACKET_SIZE 64
#define SIS_PKT_LEN_OFFSET 0
#define SIS_PKT_REPORT_OFFSET 2 /* Report ID/type */
#define SIS_PKT_CONTACT_OFFSET 3 /* First contact */
#define SIS_SCAN_TIME_LEN 2
/* Supported report types */
#define SIS_ALL_IN_ONE_PACKAGE 0x10
#define SIS_PKT_IS_TOUCH(x) (((x) & 0x0f) == 0x01)
#define SIS_PKT_IS_HIDI2C(x) (((x) & 0x0f) == 0x06)
/* Contact properties within report */
#define SIS_PKT_HAS_AREA(x) ((x) & BIT(4))
#define SIS_PKT_HAS_PRESSURE(x) ((x) & BIT(5))
#define SIS_PKT_HAS_SCANTIME(x) ((x) & BIT(6))
/* Contact size */
#define SIS_BASE_LEN_PER_CONTACT 6
#define SIS_AREA_LEN_PER_CONTACT 2
#define SIS_PRESSURE_LEN_PER_CONTACT 1
/* Offsets within contact data */
#define SIS_CONTACT_STATUS_OFFSET 0
#define SIS_CONTACT_ID_OFFSET 1 /* Contact ID */
#define SIS_CONTACT_X_OFFSET 2
#define SIS_CONTACT_Y_OFFSET 4
#define SIS_CONTACT_WIDTH_OFFSET 6
#define SIS_CONTACT_HEIGHT_OFFSET 7
#define SIS_CONTACT_PRESSURE_OFFSET(id) (SIS_PKT_HAS_AREA(id) ? 8 : 6)
/* Individual contact state */
#define SIS_STATUS_UP 0x0
#define SIS_STATUS_DOWN 0x3
/* Touchscreen parameters */
#define SIS_MAX_FINGERS 10
#define SIS_MAX_X 4095
#define SIS_MAX_Y 4095
#define SIS_MAX_PRESSURE 255
/* Resolution diagonal */
#define SIS_AREA_LENGTH_LONGER 5792
/*((SIS_MAX_X^2) + (SIS_MAX_Y^2))^0.5*/
#define SIS_AREA_LENGTH_SHORT 5792
#define SIS_AREA_UNIT (5792 / 32)
struct sis_ts_data {
struct i2c_client *client;
struct input_dev *input;
struct gpio_desc *attn_gpio;
struct gpio_desc *reset_gpio;
u8 packet[SIS_MAX_PACKET_SIZE];
};
static int sis_read_packet(struct i2c_client *client, u8 *buf,
unsigned int *num_contacts,
unsigned int *contact_size)
{
int count_idx;
int ret;
u16 len;
u16 crc, pkg_crc;
u8 report_id;
ret = i2c_master_recv(client, buf, SIS_MAX_PACKET_SIZE);
if (ret <= 0)
return -EIO;
len = get_unaligned_le16(&buf[SIS_PKT_LEN_OFFSET]);
if (len > SIS_MAX_PACKET_SIZE) {
dev_err(&client->dev,
"%s: invalid packet length (%d vs %d)\n",
__func__, len, SIS_MAX_PACKET_SIZE);
return -E2BIG;
}
if (len < 10)
return -EINVAL;
report_id = buf[SIS_PKT_REPORT_OFFSET];
count_idx = len - 1;
*contact_size = SIS_BASE_LEN_PER_CONTACT;
if (report_id != SIS_ALL_IN_ONE_PACKAGE) {
if (SIS_PKT_IS_TOUCH(report_id)) {
/*
* Calculate CRC ignoring packet length
* in the beginning and CRC transmitted
* at the end of the packet.
*/
crc = crc_itu_t(0, buf + 2, len - 2 - 2);
pkg_crc = get_unaligned_le16(&buf[len - 2]);
if (crc != pkg_crc) {
dev_err(&client->dev,
"%s: CRC Error (%d vs %d)\n",
__func__, crc, pkg_crc);
return -EINVAL;
}
count_idx -= 2;
} else if (!SIS_PKT_IS_HIDI2C(report_id)) {
dev_err(&client->dev,
"%s: invalid packet ID %#02x\n",
__func__, report_id);
return -EINVAL;
}
if (SIS_PKT_HAS_SCANTIME(report_id))
count_idx -= SIS_SCAN_TIME_LEN;
if (SIS_PKT_HAS_AREA(report_id))
*contact_size += SIS_AREA_LEN_PER_CONTACT;
if (SIS_PKT_HAS_PRESSURE(report_id))
*contact_size += SIS_PRESSURE_LEN_PER_CONTACT;
}
*num_contacts = buf[count_idx];
return 0;
}
static int sis_ts_report_contact(struct sis_ts_data *ts, const u8 *data, u8 id)
{
struct input_dev *input = ts->input;
int slot;
u8 status = data[SIS_CONTACT_STATUS_OFFSET];
u8 pressure;
u8 height, width;
u16 x, y;
if (status != SIS_STATUS_DOWN && status != SIS_STATUS_UP) {
dev_err(&ts->client->dev, "Unexpected touch status: %#02x\n",
data[SIS_CONTACT_STATUS_OFFSET]);
return -EINVAL;
}
slot = input_mt_get_slot_by_key(input, data[SIS_CONTACT_ID_OFFSET]);
if (slot < 0)
return -ENOENT;
input_mt_slot(input, slot);
input_mt_report_slot_state(input, MT_TOOL_FINGER,
status == SIS_STATUS_DOWN);
if (status == SIS_STATUS_DOWN) {
pressure = height = width = 1;
if (id != SIS_ALL_IN_ONE_PACKAGE) {
if (SIS_PKT_HAS_AREA(id)) {
width = data[SIS_CONTACT_WIDTH_OFFSET];
height = data[SIS_CONTACT_HEIGHT_OFFSET];
}
if (SIS_PKT_HAS_PRESSURE(id))
pressure =
data[SIS_CONTACT_PRESSURE_OFFSET(id)];
}
x = get_unaligned_le16(&data[SIS_CONTACT_X_OFFSET]);
y = get_unaligned_le16(&data[SIS_CONTACT_Y_OFFSET]);
input_report_abs(input, ABS_MT_TOUCH_MAJOR,
width * SIS_AREA_UNIT);
input_report_abs(input, ABS_MT_TOUCH_MINOR,
height * SIS_AREA_UNIT);
input_report_abs(input, ABS_MT_PRESSURE, pressure);
input_report_abs(input, ABS_MT_POSITION_X, x);
input_report_abs(input, ABS_MT_POSITION_Y, y);
}
return 0;
}
static void sis_ts_handle_packet(struct sis_ts_data *ts)
{
const u8 *contact;
unsigned int num_to_report = 0;
unsigned int num_contacts;
unsigned int num_reported;
unsigned int contact_size;
int error;
u8 report_id;
do {
error = sis_read_packet(ts->client, ts->packet,
&num_contacts, &contact_size);
if (error)
break;
if (num_to_report == 0) {
num_to_report = num_contacts;
} else if (num_contacts != 0) {
dev_err(&ts->client->dev,
"%s: nonzero (%d) point count in tail packet\n",
__func__, num_contacts);
break;
}
report_id = ts->packet[SIS_PKT_REPORT_OFFSET];
contact = &ts->packet[SIS_PKT_CONTACT_OFFSET];
num_reported = 0;
while (num_to_report > 0) {
error = sis_ts_report_contact(ts, contact, report_id);
if (error)
break;
contact += contact_size;
num_to_report--;
num_reported++;
if (report_id != SIS_ALL_IN_ONE_PACKAGE &&
num_reported >= 5) {
/*
* The remainder of contacts is sent
* in the 2nd packet.
*/
break;
}
}
} while (num_to_report > 0);
input_mt_sync_frame(ts->input);
input_sync(ts->input);
}
static irqreturn_t sis_ts_irq_handler(int irq, void *dev_id)
{
struct sis_ts_data *ts = dev_id;
do {
sis_ts_handle_packet(ts);
} while (ts->attn_gpio && gpiod_get_value_cansleep(ts->attn_gpio));
return IRQ_HANDLED;
}
static void sis_ts_reset(struct sis_ts_data *ts)
{
if (ts->reset_gpio) {
/* Get out of reset */
usleep_range(1000, 2000);
gpiod_set_value(ts->reset_gpio, 1);
usleep_range(1000, 2000);
gpiod_set_value(ts->reset_gpio, 0);
msleep(100);
}
}
static int sis_ts_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct sis_ts_data *ts;
struct input_dev *input;
int error;
ts = devm_kzalloc(&client->dev, sizeof(*ts), GFP_KERNEL);
if (!ts)
return -ENOMEM;
ts->client = client;
ts->attn_gpio = devm_gpiod_get_optional(&client->dev,
"attn", GPIOD_IN);
if (IS_ERR(ts->attn_gpio)) {
error = PTR_ERR(ts->attn_gpio);
if (error != -EPROBE_DEFER)
dev_err(&client->dev,
"Failed to get attention GPIO: %d\n", error);
return error;
}
ts->reset_gpio = devm_gpiod_get_optional(&client->dev,
"reset", GPIOD_OUT_LOW);
if (IS_ERR(ts->reset_gpio)) {
error = PTR_ERR(ts->reset_gpio);
if (error != -EPROBE_DEFER)
dev_err(&client->dev,
"Failed to get reset GPIO: %d\n", error);
return error;
}
sis_ts_reset(ts);
ts->input = input = devm_input_allocate_device(&client->dev);
if (!input) {
dev_err(&client->dev, "Failed to allocate input device\n");
return -ENOMEM;
}
input->name = "SiS Touchscreen";
input->id.bustype = BUS_I2C;
input_set_abs_params(input, ABS_MT_POSITION_X, 0, SIS_MAX_X, 0, 0);
input_set_abs_params(input, ABS_MT_POSITION_Y, 0, SIS_MAX_Y, 0, 0);
input_set_abs_params(input, ABS_MT_PRESSURE, 0, SIS_MAX_PRESSURE, 0, 0);
input_set_abs_params(input, ABS_MT_TOUCH_MAJOR,
0, SIS_AREA_LENGTH_LONGER, 0, 0);
input_set_abs_params(input, ABS_MT_TOUCH_MINOR,
0, SIS_AREA_LENGTH_SHORT, 0, 0);
error = input_mt_init_slots(input, SIS_MAX_FINGERS, INPUT_MT_DIRECT);
if (error) {
dev_err(&client->dev,
"Failed to initialize MT slots: %d\n", error);
return error;
}
error = devm_request_threaded_irq(&client->dev, client->irq,
NULL, sis_ts_irq_handler,
IRQF_ONESHOT,
client->name, ts);
if (error) {
dev_err(&client->dev, "Failed to request IRQ: %d\n", error);
return error;
}
error = input_register_device(ts->input);
if (error) {
dev_err(&client->dev,
"Failed to register input device: %d\n", error);
return error;
}
return 0;
}
#ifdef CONFIG_OF
static const struct of_device_id sis_ts_dt_ids[] = {
{ .compatible = "sis,9200-ts" },
{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, sis_ts_dt_ids);
#endif
static const struct i2c_device_id sis_ts_id[] = {
{ SIS_I2C_NAME, 0 },
{ "9200-ts", 0 },
{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(i2c, sis_ts_id);
static struct i2c_driver sis_ts_driver = {
.driver = {
.name = SIS_I2C_NAME,
.of_match_table = of_match_ptr(sis_ts_dt_ids),
},
.probe = sis_ts_probe,
.id_table = sis_ts_id,
};
module_i2c_driver(sis_ts_driver);
MODULE_DESCRIPTION("SiS 9200 Family Touchscreen Driver");
MODULE_LICENSE("GPL v2");
MODULE_AUTHOR("Mika Penttilä <mika.penttila@nextfour.com>");
