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#include <linux/delay.h>#include <linux/gpio/consumer.h>#include <linux/i2c.h>#include <linux/input.h>#include <linux/input/mt.h>#include <linux/input/touchscreen.h>#include <linux/interrupt.h>#include <linux/kernel.h>#include <linux/module.h>#include <linux/property.h>#include <linux/regulator/consumer.h>#include <linux/slab.h>
#define MODE_DATA_RAW 0x5A
#define MSG2138_MAX_FINGERS 2#define MSG2638_MAX_FINGERS 5
#define MAX_BUTTONS 4
#define CHIP_ON_DELAY_MS 15#define FIRMWARE_ON_DELAY_MS 50#define RESET_DELAY_MIN_US 10000#define RESET_DELAY_MAX_US 11000
struct msg_chip_data { irq_handler_t irq_handler; unsigned int max_fingers;};
struct msg2138_packet { u8 xy_hi; /* higher bits of x and y coordinates */ u8 x_low; u8 y_low;};
struct msg2138_touch_event { u8 magic; struct msg2138_packet pkt[MSG2138_MAX_FINGERS]; u8 checksum;};
struct msg2638_packet { u8 xy_hi; /* higher bits of x and y coordinates */ u8 x_low; u8 y_low; u8 pressure;};
struct msg2638_touch_event { u8 mode; struct msg2638_packet pkt[MSG2638_MAX_FINGERS]; u8 proximity; u8 checksum;};
struct msg2638_ts_data { struct i2c_client *client; struct input_dev *input_dev; struct touchscreen_properties prop; struct regulator_bulk_data supplies[2]; struct gpio_desc *reset_gpiod; int max_fingers; u32 keycodes[MAX_BUTTONS]; int num_keycodes;};
static u8 msg2638_checksum(u8 *data, u32 length){ s32 sum = 0; u32 i;
for (i = 0; i < length; i++) sum += data[i];
return (u8)((-sum) & 0xFF);}
static void msg2138_report_keys(struct msg2638_ts_data *msg2638, u8 keys){ int i;
/* keys can be 0x00 or 0xff when all keys have been released */ if (keys == 0xff) keys = 0;
for (i = 0; i < msg2638->num_keycodes; ++i) input_report_key(msg2638->input_dev, msg2638->keycodes[i], keys & BIT(i));}
static irqreturn_t msg2138_ts_irq_handler(int irq, void *msg2638_handler){ struct msg2638_ts_data *msg2638 = msg2638_handler; struct i2c_client *client = msg2638->client; struct input_dev *input = msg2638->input_dev; struct msg2138_touch_event touch_event; u32 len = sizeof(touch_event); struct i2c_msg msg[] = { { .addr = client->addr, .flags = I2C_M_RD, .len = sizeof(touch_event), .buf = (u8 *)&touch_event, }, }; struct msg2138_packet *p0, *p1; u16 x, y, delta_x, delta_y; int ret;
ret = i2c_transfer(client->adapter, msg, ARRAY_SIZE(msg)); if (ret != ARRAY_SIZE(msg)) { dev_err(&client->dev, "Failed I2C transfer in irq handler: %d\n", ret < 0 ? ret : -EIO); goto out; }
if (msg2638_checksum((u8 *)&touch_event, len - 1) != touch_event.checksum) { dev_err(&client->dev, "Failed checksum!\n"); goto out; }
p0 = &touch_event.pkt[0]; p1 = &touch_event.pkt[1];
/* Ignore non-pressed finger data, but check for key code */ if (p0->xy_hi == 0xFF && p0->x_low == 0xFF && p0->y_low == 0xFF) { if (p1->xy_hi == 0xFF && p1->y_low == 0xFF) msg2138_report_keys(msg2638, p1->x_low); goto report; }
x = ((p0->xy_hi & 0xF0) << 4) | p0->x_low; y = ((p0->xy_hi & 0x0F) << 8) | p0->y_low;
input_mt_slot(input, 0); input_mt_report_slot_state(input, MT_TOOL_FINGER, true); touchscreen_report_pos(input, &msg2638->prop, x, y, true);
/* Ignore non-pressed finger data */ if (p1->xy_hi == 0xFF && p1->x_low == 0xFF && p1->y_low == 0xFF) goto report;
/* Second finger is reported as a delta position */ delta_x = ((p1->xy_hi & 0xF0) << 4) | p1->x_low; delta_y = ((p1->xy_hi & 0x0F) << 8) | p1->y_low;
/* Ignore second finger if both deltas equal 0 */ if (delta_x == 0 && delta_y == 0) goto report;
x += delta_x; y += delta_y;
input_mt_slot(input, 1); input_mt_report_slot_state(input, MT_TOOL_FINGER, true); touchscreen_report_pos(input, &msg2638->prop, x, y, true);
report: input_mt_sync_frame(msg2638->input_dev); input_sync(msg2638->input_dev);
out: return IRQ_HANDLED;}
static irqreturn_t msg2638_ts_irq_handler(int irq, void *msg2638_handler){ struct msg2638_ts_data *msg2638 = msg2638_handler; struct i2c_client *client = msg2638->client; struct input_dev *input = msg2638->input_dev; struct msg2638_touch_event touch_event; u32 len = sizeof(touch_event); struct i2c_msg msg[] = { { .addr = client->addr, .flags = I2C_M_RD, .len = sizeof(touch_event), .buf = (u8 *)&touch_event, }, }; struct msg2638_packet *p; u16 x, y; int ret; int i;
ret = i2c_transfer(client->adapter, msg, ARRAY_SIZE(msg)); if (ret != ARRAY_SIZE(msg)) { dev_err(&client->dev, "Failed I2C transfer in irq handler: %d\n", ret < 0 ? ret : -EIO); goto out; }
if (touch_event.mode != MODE_DATA_RAW) goto out;
if (msg2638_checksum((u8 *)&touch_event, len - 1) != touch_event.checksum) { dev_err(&client->dev, "Failed checksum!\n"); goto out; }
for (i = 0; i < msg2638->max_fingers; i++) { p = &touch_event.pkt[i];
/* Ignore non-pressed finger data */ if (p->xy_hi == 0xFF && p->x_low == 0xFF && p->y_low == 0xFF) continue;
x = (((p->xy_hi & 0xF0) << 4) | p->x_low); y = (((p->xy_hi & 0x0F) << 8) | p->y_low);
input_mt_slot(input, i); input_mt_report_slot_state(input, MT_TOOL_FINGER, true); touchscreen_report_pos(input, &msg2638->prop, x, y, true); }
input_mt_sync_frame(msg2638->input_dev); input_sync(msg2638->input_dev);
out: return IRQ_HANDLED;}
static void msg2638_reset(struct msg2638_ts_data *msg2638){ gpiod_set_value_cansleep(msg2638->reset_gpiod, 1); usleep_range(RESET_DELAY_MIN_US, RESET_DELAY_MAX_US); gpiod_set_value_cansleep(msg2638->reset_gpiod, 0); msleep(FIRMWARE_ON_DELAY_MS);}
static int msg2638_start(struct msg2638_ts_data *msg2638){ int error;
error = regulator_bulk_enable(ARRAY_SIZE(msg2638->supplies), msg2638->supplies); if (error) { dev_err(&msg2638->client->dev, "Failed to enable regulators: %d\n", error); return error; }
msleep(CHIP_ON_DELAY_MS);
msg2638_reset(msg2638);
enable_irq(msg2638->client->irq);
return 0;}
static int msg2638_stop(struct msg2638_ts_data *msg2638){ int error;
disable_irq(msg2638->client->irq);
error = regulator_bulk_disable(ARRAY_SIZE(msg2638->supplies), msg2638->supplies); if (error) { dev_err(&msg2638->client->dev, "Failed to disable regulators: %d\n", error); return error; }
return 0;}
static int msg2638_input_open(struct input_dev *dev){ struct msg2638_ts_data *msg2638 = input_get_drvdata(dev);
return msg2638_start(msg2638);}
static void msg2638_input_close(struct input_dev *dev){ struct msg2638_ts_data *msg2638 = input_get_drvdata(dev);
msg2638_stop(msg2638);}
static int msg2638_init_input_dev(struct msg2638_ts_data *msg2638){ struct device *dev = &msg2638->client->dev; struct input_dev *input_dev; int error; int i;
input_dev = devm_input_allocate_device(dev); if (!input_dev) { dev_err(dev, "Failed to allocate input device.\n"); return -ENOMEM; }
input_set_drvdata(input_dev, msg2638); msg2638->input_dev = input_dev;
input_dev->name = "MStar TouchScreen"; input_dev->phys = "input/ts"; input_dev->id.bustype = BUS_I2C; input_dev->open = msg2638_input_open; input_dev->close = msg2638_input_close;
if (msg2638->num_keycodes) { input_dev->keycode = msg2638->keycodes; input_dev->keycodemax = msg2638->num_keycodes; input_dev->keycodesize = sizeof(msg2638->keycodes[0]); for (i = 0; i < msg2638->num_keycodes; i++) input_set_capability(input_dev, EV_KEY, msg2638->keycodes[i]); }
input_set_capability(input_dev, EV_ABS, ABS_MT_POSITION_X); input_set_capability(input_dev, EV_ABS, ABS_MT_POSITION_Y);
touchscreen_parse_properties(input_dev, true, &msg2638->prop); if (!msg2638->prop.max_x || !msg2638->prop.max_y) { dev_err(dev, "touchscreen-size-x and/or touchscreen-size-y not set in properties\n"); return -EINVAL; }
error = input_mt_init_slots(input_dev, msg2638->max_fingers, INPUT_MT_DIRECT | INPUT_MT_DROP_UNUSED); if (error) { dev_err(dev, "Failed to initialize MT slots: %d\n", error); return error; }
error = input_register_device(input_dev); if (error) { dev_err(dev, "Failed to register input device: %d\n", error); return error; }
return 0;}
static int msg2638_ts_probe(struct i2c_client *client){ const struct msg_chip_data *chip_data; struct device *dev = &client->dev; struct msg2638_ts_data *msg2638; int error;
if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) { dev_err(dev, "Failed to assert adapter's support for plain I2C.\n"); return -ENXIO; }
msg2638 = devm_kzalloc(dev, sizeof(*msg2638), GFP_KERNEL); if (!msg2638) return -ENOMEM;
msg2638->client = client; i2c_set_clientdata(client, msg2638);
chip_data = device_get_match_data(&client->dev); if (!chip_data || !chip_data->max_fingers) { dev_err(dev, "Invalid or missing chip data\n"); return -EINVAL; }
msg2638->max_fingers = chip_data->max_fingers;
msg2638->supplies[0].supply = "vdd"; msg2638->supplies[1].supply = "vddio"; error = devm_regulator_bulk_get(dev, ARRAY_SIZE(msg2638->supplies), msg2638->supplies); if (error) { dev_err(dev, "Failed to get regulators: %d\n", error); return error; }
msg2638->reset_gpiod = devm_gpiod_get(dev, "reset", GPIOD_OUT_LOW); if (IS_ERR(msg2638->reset_gpiod)) { error = PTR_ERR(msg2638->reset_gpiod); dev_err(dev, "Failed to request reset GPIO: %d\n", error); return error; }
msg2638->num_keycodes = device_property_count_u32(dev, "linux,keycodes"); if (msg2638->num_keycodes == -EINVAL) { msg2638->num_keycodes = 0; } else if (msg2638->num_keycodes < 0) { dev_err(dev, "Unable to parse linux,keycodes property: %d\n", msg2638->num_keycodes); return msg2638->num_keycodes; } else if (msg2638->num_keycodes > ARRAY_SIZE(msg2638->keycodes)) { dev_warn(dev, "Found %d linux,keycodes but max is %zd, ignoring the rest\n", msg2638->num_keycodes, ARRAY_SIZE(msg2638->keycodes)); msg2638->num_keycodes = ARRAY_SIZE(msg2638->keycodes); }
if (msg2638->num_keycodes > 0) { error = device_property_read_u32_array(dev, "linux,keycodes", msg2638->keycodes, msg2638->num_keycodes); if (error) { dev_err(dev, "Unable to read linux,keycodes values: %d\n", error); return error; } }
error = devm_request_threaded_irq(dev, client->irq, NULL, chip_data->irq_handler, IRQF_ONESHOT | IRQF_NO_AUTOEN, client->name, msg2638); if (error) { dev_err(dev, "Failed to request IRQ: %d\n", error); return error; }
error = msg2638_init_input_dev(msg2638); if (error) { dev_err(dev, "Failed to initialize input device: %d\n", error); return error; }
return 0;}
static int msg2638_suspend(struct device *dev){ struct i2c_client *client = to_i2c_client(dev); struct msg2638_ts_data *msg2638 = i2c_get_clientdata(client);
guard(mutex)(&msg2638->input_dev->mutex);
if (input_device_enabled(msg2638->input_dev)) msg2638_stop(msg2638);
return 0;}
static int msg2638_resume(struct device *dev){ struct i2c_client *client = to_i2c_client(dev); struct msg2638_ts_data *msg2638 = i2c_get_clientdata(client); int error;
guard(mutex)(&msg2638->input_dev->mutex);
if (input_device_enabled(msg2638->input_dev)) { error = msg2638_start(msg2638); if (error) return error; }
return 0;}
static DEFINE_SIMPLE_DEV_PM_OPS(msg2638_pm_ops, msg2638_suspend, msg2638_resume);
static const struct msg_chip_data msg2138_data = { .irq_handler = msg2138_ts_irq_handler, .max_fingers = MSG2138_MAX_FINGERS,};
static const struct msg_chip_data msg2638_data = { .irq_handler = msg2638_ts_irq_handler, .max_fingers = MSG2638_MAX_FINGERS,};
static const struct of_device_id msg2638_of_match[] = { { .compatible = "mstar,msg2138", .data = &msg2138_data }, { .compatible = "mstar,msg2638", .data = &msg2638_data }, { }};MODULE_DEVICE_TABLE(of, msg2638_of_match);
static struct i2c_driver msg2638_ts_driver = { .probe = msg2638_ts_probe, .driver = { .name = "MStar-TS", .pm = pm_sleep_ptr(&msg2638_pm_ops), .of_match_table = msg2638_of_match, },};module_i2c_driver(msg2638_ts_driver);
MODULE_AUTHOR("Vincent Knecht <vincent.knecht@mailoo.org>");MODULE_DESCRIPTION("MStar MSG2638 touchscreen driver");MODULE_LICENSE("GPL v2");