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Input: zinitix - support the 6-byte/count touch report used by bt532 #449

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Input: zinitix - support the 6-byte/count touch report used by bt532 #449

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69 changes: 57 additions & 12 deletions drivers/input/touchscreen/zinitix.c
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Original file line number Diff line number Diff line change
Expand Up @@ -135,26 +135,47 @@
#define CHIP_ON_DELAY 15 // ms
#define FIRMWARE_ON_DELAY 40 // ms

/*
* Two Zinitix touch-report layouts exist in the wild. The default is an 8-byte
* per-contact stride with a per-finger bitmask in report byte[2]. Some firmware
* (e.g. bt532 on the Samsung Galaxy Tab A 8.0) packs contacts at a 6-byte stride
* and reports a finger COUNT in byte[2] instead of a bitmask. Selected per
* compatible via the of_device_id .data below.
*/
struct zinitix_chip_data {
unsigned int coord_stride; /* per-contact byte stride in the report */
bool finger_count; /* byte[2] is a finger count, not a bitmask */
};

static const struct zinitix_chip_data zinitix_bt532_data = {
.coord_stride = 6,
.finger_count = true,
};

struct point_coord {
__le16 x;
__le16 y;
u8 width;
u8 sub_status;
// currently unused, but needed as padding:
u8 minor_width;
u8 angle;
/*
* 8-byte-stride firmware appends two unused bytes here (minor_width,
* angle); the report is parsed at the chip's coord_stride, so on that
* firmware they are simply skipped rather than being part of this struct.
*/
};

struct touch_event {
__le16 status;
u8 finger_mask;
u8 time_stamp;
struct point_coord point_coord[MAX_SUPPORTED_FINGER_NUM];
/* raw per-contact bytes, parsed at the chip's coord_stride (max 8) */
u8 coords[MAX_SUPPORTED_FINGER_NUM * 8];
};

struct bt541_ts_data {
struct i2c_client *client;
struct input_dev *input_dev;
const struct zinitix_chip_data *chip;
struct touchscreen_properties prop;
struct regulator_bulk_data supplies[2];
u32 zinitix_mode;
Expand Down Expand Up @@ -444,6 +465,8 @@ static irqreturn_t zinitix_ts_irq_handler(int irq, void *bt541_handler)
{
struct bt541_ts_data *bt541 = bt541_handler;
struct i2c_client *client = bt541->client;
unsigned int stride = bt541->chip ? bt541->chip->coord_stride : 8;
bool finger_count = bt541->chip ? bt541->chip->finger_count : false;
struct touch_event touch_event;
unsigned long finger_mask;
__le16 icon_events;
Expand All @@ -452,8 +475,11 @@ static irqreturn_t zinitix_ts_irq_handler(int irq, void *bt541_handler)

memset(&touch_event, 0, sizeof(struct touch_event));

/* header (status, finger_mask, time_stamp) + one stride per contact */
error = zinitix_read_data(bt541->client, ZINITIX_POINT_STATUS_REG,
&touch_event, sizeof(struct touch_event));
&touch_event,
offsetof(struct touch_event, coords) +
MAX_SUPPORTED_FINGER_NUM * stride);
if (error) {
dev_err(&client->dev, "Failed to read in touchpoint struct\n");
goto out;
Expand All @@ -470,13 +496,31 @@ static irqreturn_t zinitix_ts_irq_handler(int irq, void *bt541_handler)
zinitix_report_keys(bt541, le16_to_cpu(icon_events));
}

finger_mask = touch_event.finger_mask;
for_each_set_bit(i, &finger_mask, MAX_SUPPORTED_FINGER_NUM) {
const struct point_coord *p = &touch_event.point_coord[i];
if (finger_count) {
/*
* On this firmware byte[2] is a finger COUNT, not a bitmask: a
* 2-finger report carries 0x02, so for_each_set_bit() would look
* only at slot 1 and silently drop slot 0. The chip marks every
* populated contact with SUB_BIT_EXIST, so iterate all slots and
* report the present ones.
*/
for (i = 0; i < MAX_SUPPORTED_FINGER_NUM; i++) {
const struct point_coord *p =
(const struct point_coord *)&touch_event.coords[i * stride];

/* Only process contacts that are actually reported */
if (p->sub_status & SUB_BIT_EXIST)
zinitix_report_finger(bt541, i, p);
if (p->sub_status & SUB_BIT_EXIST)
zinitix_report_finger(bt541, i, p);
}
} else {
/* default: byte[2] is a per-finger bitmask */
finger_mask = touch_event.finger_mask;
for_each_set_bit(i, &finger_mask, MAX_SUPPORTED_FINGER_NUM) {
const struct point_coord *p =
(const struct point_coord *)&touch_event.coords[i * stride];

if (p->sub_status & SUB_BIT_EXIST)
zinitix_report_finger(bt541, i, p);
}
}

input_mt_sync_frame(bt541->input_dev);
Expand Down Expand Up @@ -627,6 +671,7 @@ static int zinitix_ts_probe(struct i2c_client *client)
return -ENOMEM;

bt541->client = client;
bt541->chip = device_get_match_data(&client->dev);
i2c_set_clientdata(client, bt541);

error = zinitix_init_regulators(bt541);
Expand Down Expand Up @@ -741,7 +786,7 @@ static const struct of_device_id zinitix_of_match[] = {
{ .compatible = "zinitix,bt431" },
{ .compatible = "zinitix,bt432" },
{ .compatible = "zinitix,bt531" },
{ .compatible = "zinitix,bt532" },
{ .compatible = "zinitix,bt532", .data = &zinitix_bt532_data },
{ .compatible = "zinitix,bt538" },
{ .compatible = "zinitix,bt541" },
{ .compatible = "zinitix,bt548" },
Expand Down
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