[PATCH v7 0/4] input: elants: Support Asus TF300T and Nexus 7 touchscreen

[PATCH v7 0/4] input: elants: Support Asus TF300T and Nexus 7 touchscreen

[Michał Mirosław]

This series cleans up the driver a bit and implements changes needed to
support EKTF3624-based touchscreen used in Asus TF300T, Google Nexus 7
and similar Tegra3-based tablets.

---
v2: extended with Dmitry's patches (replaced v1 patches 3 and 4)
v3: rebased for v5.7-rc1
v4: rebased onto v5.7-rc2+ (current Linus' master)
    update "remove unused axes" and "refactor
      elants_i2c_execute_command()" patches after review
    add David's patch converting DT binding to YAML
v5: rebased onto dtor/input/for-linus
v6: rebased onto newer dtor/input/for-linus
    remove yet unused constants from patch 1
    added a new drive-by cleanup (last patch)
v7: rebased onto current dtor/input/for-next
---

Dmitry Osipenko (1):
  input: elants: support 0x66 reply opcode for reporting touches

Michał Mirosław (3):
  input: elants: document some registers and values
  input: elants: support old touch report format
  input: elants: read touchscreen size for EKTF3624

 drivers/input/touchscreen/elants_i2c.c | 149 +++++++++++++++++++++----
 1 file changed, 127 insertions(+), 22 deletions(-)

-- 
2.20.1

[PATCH v7 2/4] input: elants: support old touch report format

[Michał Mirosław]

Support ELAN touchpad sensor with older firmware as found on eg. Asus
Transformer Pads.

Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Reviewed-by: Dmitry Osipenko <digetx@gmail.com>
Tested-by: Dmitry Osipenko <digetx@gmail.com>
---
 drivers/input/touchscreen/elants_i2c.c | 36 ++++++++++++++++++--------
 1 file changed, 25 insertions(+), 11 deletions(-)

diff --git a/drivers/input/touchscreen/elants_i2c.c b/drivers/input/touchscreen/elants_i2c.c
index d51cb910fba1..f1bf3e000e96 100644
--- a/drivers/input/touchscreen/elants_i2c.c
+++ b/drivers/input/touchscreen/elants_i2c.c
@@ -69,6 +69,7 @@
 #define CMD_HEADER_REK		0x66
 
 /* FW position data */
+#define PACKET_SIZE_OLD		40
 #define PACKET_SIZE		55
 #define MAX_CONTACT_NUM		10
 #define FW_POS_HEADER		0
@@ -853,7 +854,8 @@ static int elants_i2c_fw_update(struct elants_data *ts)
  * Event reporting.
  */
 
-static void elants_i2c_mt_event(struct elants_data *ts, u8 *buf)
+static void elants_i2c_mt_event(struct elants_data *ts, u8 *buf,
+				size_t report_len)
 {
 	struct input_dev *input = ts->input;
 	unsigned int n_fingers;
@@ -866,7 +868,8 @@ static void elants_i2c_mt_event(struct elants_data *ts, u8 *buf)
 			buf[FW_POS_STATE];
 
 	dev_dbg(&ts->client->dev,
-		"n_fingers: %u, state: %04x\n",  n_fingers, finger_state);
+		"n_fingers: %u, state: %04x, report_len: %zu\n",
+		n_fingers, finger_state, report_len);
 
 	/* Note: all fingers have the same tool type */
 	tool_type = buf[FW_POS_TOOL_TYPE] & BIT(0) ?
@@ -880,8 +883,16 @@ static void elants_i2c_mt_event(struct elants_data *ts, u8 *buf)
 			pos = &buf[FW_POS_XY + i * 3];
 			x = (((u16)pos[0] & 0xf0) << 4) | pos[1];
 			y = (((u16)pos[0] & 0x0f) << 8) | pos[2];
-			p = buf[FW_POS_PRESSURE + i];
-			w = buf[FW_POS_WIDTH + i];
+			if (report_len == PACKET_SIZE_OLD) {
+				w = buf[FW_POS_WIDTH + i / 2];
+				w >>= 4 * (~i & 1);	// little-endian-nibbles
+				w |= w << 4;
+				w |= !w;
+				p = w;
+			} else {
+				p = buf[FW_POS_PRESSURE + i];
+				w = buf[FW_POS_WIDTH + i];
+			}
 
 			dev_dbg(&ts->client->dev, "i=%d x=%d y=%d p=%d w=%d\n",
 				i, x, y, p, w);
@@ -913,7 +924,8 @@ static u8 elants_i2c_calculate_checksum(u8 *buf)
 	return checksum;
 }
 
-static void elants_i2c_event(struct elants_data *ts, u8 *buf)
+static void elants_i2c_event(struct elants_data *ts, u8 *buf,
+			     size_t report_len)
 {
 	u8 checksum = elants_i2c_calculate_checksum(buf);
 
@@ -927,7 +939,7 @@ static void elants_i2c_event(struct elants_data *ts, u8 *buf)
 			 "%s: unknown packet type: %02x\n",
 			 __func__, buf[FW_POS_HEADER]);
 	else
-		elants_i2c_mt_event(ts, buf);
+		elants_i2c_mt_event(ts, buf, report_len);
 }
 
 static irqreturn_t elants_i2c_irq(int irq, void *_dev)
@@ -985,7 +997,8 @@ static irqreturn_t elants_i2c_irq(int irq, void *_dev)
 			break;
 
 		case QUEUE_HEADER_SINGLE:
-			elants_i2c_event(ts, &ts->buf[HEADER_SIZE]);
+			elants_i2c_event(ts, &ts->buf[HEADER_SIZE],
+					 ts->buf[FW_HDR_LENGTH]);
 			break;
 
 		case QUEUE_HEADER_NORMAL:
@@ -998,17 +1011,18 @@ static irqreturn_t elants_i2c_irq(int irq, void *_dev)
 			}
 
 			report_len = ts->buf[FW_HDR_LENGTH] / report_count;
-			if (report_len != PACKET_SIZE) {
+			if (report_len != PACKET_SIZE &&
+			    report_len != PACKET_SIZE_OLD) {
 				dev_err(&client->dev,
-					"mismatching report length: %*ph\n",
+					"unsupported report length: %*ph\n",
 					HEADER_SIZE, ts->buf);
 				break;
 			}
 
 			for (i = 0; i < report_count; i++) {
 				u8 *buf = ts->buf + HEADER_SIZE +
-							i * PACKET_SIZE;
-				elants_i2c_event(ts, buf);
+					  i * report_len;
+				elants_i2c_event(ts, buf, report_len);
 			}
 			break;
 
-- 
2.20.1

[PATCH v7 1/4] input: elants: document some registers and values

[Michał Mirosław]

Add information found in downstream kernels, to make the code less
magic.

Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Reviewed-by: Dmitry Osipenko <digetx@gmail.com>
Tested-by: Dmitry Osipenko <digetx@gmail.com>
---
 drivers/input/touchscreen/elants_i2c.c | 18 +++++++++++++-----
 1 file changed, 13 insertions(+), 5 deletions(-)

diff --git a/drivers/input/touchscreen/elants_i2c.c b/drivers/input/touchscreen/elants_i2c.c
index 50c348297e38..d51cb910fba1 100644
--- a/drivers/input/touchscreen/elants_i2c.c
+++ b/drivers/input/touchscreen/elants_i2c.c
@@ -82,7 +82,7 @@
 
 #define HEADER_REPORT_10_FINGER	0x62
 
-/* Header (4 bytes) plus 3 fill 10-finger packets */
+/* Header (4 bytes) plus 3 full 10-finger packets */
 #define MAX_PACKET_SIZE		169
 
 #define BOOT_TIME_DELAY_MS	50
@@ -97,6 +97,10 @@
 #define E_INFO_PHY_SCAN		0xD7
 #define E_INFO_PHY_DRIVER	0xD8
 
+/* FW write command, 0x54 0x?? 0x0, 0x01 */
+#define E_POWER_STATE_SLEEP	0x50
+#define E_POWER_STATE_RESUME	0x58
+
 #define MAX_RETRIES		3
 #define MAX_FW_UPDATE_RETRIES	30
 
@@ -269,8 +273,8 @@ static int elants_i2c_calibrate(struct elants_data *ts)
 {
 	struct i2c_client *client = ts->client;
 	int ret, error;
-	static const u8 w_flashkey[] = { 0x54, 0xC0, 0xE1, 0x5A };
-	static const u8 rek[] = { 0x54, 0x29, 0x00, 0x01 };
+	static const u8 w_flashkey[] = { CMD_HEADER_WRITE, 0xC0, 0xE1, 0x5A };
+	static const u8 rek[] = { CMD_HEADER_WRITE, 0x29, 0x00, 0x01 };
 	static const u8 rek_resp[] = { CMD_HEADER_REK, 0x66, 0x66, 0x66 };
 
 	disable_irq(client->irq);
@@ -1388,7 +1392,9 @@ static int __maybe_unused elants_i2c_suspend(struct device *dev)
 {
 	struct i2c_client *client = to_i2c_client(dev);
 	struct elants_data *ts = i2c_get_clientdata(client);
-	const u8 set_sleep_cmd[] = { 0x54, 0x50, 0x00, 0x01 };
+	const u8 set_sleep_cmd[] = {
+		CMD_HEADER_WRITE, E_POWER_STATE_SLEEP, 0x00, 0x01
+	};
 	int retry_cnt;
 	int error;
 
@@ -1425,7 +1431,9 @@ static int __maybe_unused elants_i2c_resume(struct device *dev)
 {
 	struct i2c_client *client = to_i2c_client(dev);
 	struct elants_data *ts = i2c_get_clientdata(client);
-	const u8 set_active_cmd[] = { 0x54, 0x58, 0x00, 0x01 };
+	const u8 set_active_cmd[] = {
+		CMD_HEADER_WRITE, E_POWER_STATE_RESUME, 0x00, 0x01
+	};
 	int retry_cnt;
 	int error;
 
-- 
2.20.1

[PATCH v7 4/4] input: elants: support 0x66 reply opcode for reporting touches

[Michał Mirosław]

From: Dmitry Osipenko <digetx@gmail.com>

eKTF3624 touchscreen firmware uses two variants of the reply opcodes for
reporting touch events: one is 0x63 (used by older firmware) and other is
0x66 (used by newer firmware). The 0x66 variant is equal to 0x63 of
eKTH3500, while 0x63 needs small adjustment of the touch pressure value.

Nexus 7 tablet device has eKTF3624 touchscreen and it uses 0x66 opcode for
reporting touch events, let's support it now. Other devices, eg. ASUS TF300T,
use 0x63.

Note: CMD_HEADER_REK is used for replying to calibration requests, it has
the same 0x66 opcode number which eKTF3624 uses for reporting touches.
The calibration replies are handled separately from the the rest of the
commands in the driver by entering into ELAN_WAIT_RECALIBRATION state
and thus this change shouldn't change the old behavior.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Tested-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
---
 drivers/input/touchscreen/elants_i2c.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/drivers/input/touchscreen/elants_i2c.c b/drivers/input/touchscreen/elants_i2c.c
index c24d8cdc4251..1cbda6f20d07 100644
--- a/drivers/input/touchscreen/elants_i2c.c
+++ b/drivers/input/touchscreen/elants_i2c.c
@@ -61,6 +61,15 @@
 #define QUEUE_HEADER_NORMAL	0X63
 #define QUEUE_HEADER_WAIT	0x64
 
+/*
+ * Depending on firmware version, eKTF3624 touchscreens may utilize one of
+ * these opcodes for the touch events: 0x63 and 0x66. The 0x63 is used by
+ * older firmware version and differs from 0x66 such that touch pressure
+ * value needs to be adjusted. The 0x66 opcode of newer firmware is equal
+ * to 0x63 of eKTH3500.
+ */
+#define QUEUE_HEADER_NORMAL2	0x66
+
 /* Command header definition */
 #define CMD_HEADER_WRITE	0x54
 #define CMD_HEADER_READ		0x53
@@ -1052,7 +1061,6 @@ static irqreturn_t elants_i2c_irq(int irq, void *_dev)
 		switch (ts->buf[FW_HDR_TYPE]) {
 		case CMD_HEADER_HELLO:
 		case CMD_HEADER_RESP:
-		case CMD_HEADER_REK:
 			break;
 
 		case QUEUE_HEADER_WAIT:
@@ -1072,6 +1080,7 @@ static irqreturn_t elants_i2c_irq(int irq, void *_dev)
 			break;
 
 		case QUEUE_HEADER_NORMAL:
+		case QUEUE_HEADER_NORMAL2:
 			report_count = ts->buf[FW_HDR_COUNT];
 			if (report_count == 0 || report_count > 3) {
 				dev_err(&client->dev,
-- 
2.20.1

[PATCH v7 3/4] input: elants: read touchscreen size for EKTF3624

[Michał Mirosław]

EKTF3624 as present in Asus TF300T tablet has touchscreen size encoded
in different registers.

Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Reviewed-by: Dmitry Osipenko <digetx@gmail.com>
Tested-by: Dmitry Osipenko <digetx@gmail.com>
---
 drivers/input/touchscreen/elants_i2c.c | 84 ++++++++++++++++++++++++--
 1 file changed, 79 insertions(+), 5 deletions(-)

diff --git a/drivers/input/touchscreen/elants_i2c.c b/drivers/input/touchscreen/elants_i2c.c
index f1bf3e000e96..c24d8cdc4251 100644
--- a/drivers/input/touchscreen/elants_i2c.c
+++ b/drivers/input/touchscreen/elants_i2c.c
@@ -35,7 +35,7 @@
 #include <linux/input/mt.h>
 #include <linux/input/touchscreen.h>
 #include <linux/acpi.h>
-#include <linux/of.h>
+#include <linux/of_device.h>
 #include <linux/gpio/consumer.h>
 #include <linux/regulator/consumer.h>
 #include <asm/unaligned.h>
@@ -43,6 +43,10 @@
 /* Device, Driver information */
 #define DEVICE_NAME	"elants_i2c"
 
+/* Device IDs */
+#define EKTH3500	0
+#define EKTF3624	1
+
 /* Convert from rows or columns into resolution */
 #define ELAN_TS_RESOLUTION(n, m)   (((n) - 1) * (m))
 
@@ -94,6 +98,8 @@
 #define E_ELAN_INFO_REK		0xD0
 #define E_ELAN_INFO_TEST_VER	0xE0
 #define E_ELAN_INFO_FW_ID	0xF0
+#define E_INFO_X_RES		0x60
+#define E_INFO_Y_RES		0x63
 #define E_INFO_OSR		0xD6
 #define E_INFO_PHY_SCAN		0xD7
 #define E_INFO_PHY_DRIVER	0xD8
@@ -157,6 +163,7 @@ struct elants_data {
 
 	bool wake_irq_enabled;
 	bool keep_power_in_suspend;
+	u8 chip_id;
 
 	/* Must be last to be used for DMA operations */
 	u8 buf[MAX_PACKET_SIZE] ____cacheline_aligned;
@@ -434,7 +441,58 @@ static int elants_i2c_query_bc_version(struct elants_data *ts)
 	return 0;
 }
 
-static int elants_i2c_query_ts_info(struct elants_data *ts)
+static int elants_i2c_query_ts_info_ektf(struct elants_data *ts)
+{
+	struct i2c_client *client = ts->client;
+	int error;
+	u8 resp[4];
+	u16 phy_x, phy_y;
+	const u8 get_xres_cmd[] = {
+		CMD_HEADER_READ, E_INFO_X_RES, 0x00, 0x00
+	};
+	const u8 get_yres_cmd[] = {
+		CMD_HEADER_READ, E_INFO_Y_RES, 0x00, 0x00
+	};
+
+	/* Get X/Y size in mm */
+	error = elants_i2c_execute_command(client, get_xres_cmd,
+					   sizeof(get_xres_cmd),
+					   resp, sizeof(resp), 1,
+					   "get X size");
+	if (error)
+		return error;
+
+	phy_x = resp[2] | ((resp[3] & 0xF0) << 4);
+
+	error = elants_i2c_execute_command(client, get_yres_cmd,
+					   sizeof(get_yres_cmd),
+					   resp, sizeof(resp), 1,
+					   "get Y size");
+	if (error)
+		return error;
+
+	phy_y = resp[2] | ((resp[3] & 0xF0) << 4);
+
+	if (!phy_x || !phy_y) {
+		dev_warn(&client->dev,
+			 "invalid size data: %d x %d mm\n",
+			 phy_x, phy_y);
+		return 0;
+	}
+
+	dev_dbg(&client->dev, "phy_x=%d, phy_y=%d\n", phy_x, phy_y);
+
+	/* calculate resolution from size */
+	ts->x_max = 2240-1;
+	ts->x_res = DIV_ROUND_CLOSEST(ts->prop.max_x, phy_x);
+
+	ts->y_max = 1408-1;
+	ts->y_res = DIV_ROUND_CLOSEST(ts->prop.max_y, phy_y);
+
+	return 0;
+}
+
+static int elants_i2c_query_ts_info_ekth(struct elants_data *ts)
 {
 	struct i2c_client *client = ts->client;
 	int error;
@@ -588,8 +646,20 @@ static int elants_i2c_initialize(struct elants_data *ts)
 		error = elants_i2c_query_fw_version(ts);
 	if (!error)
 		error = elants_i2c_query_test_version(ts);
-	if (!error)
-		error = elants_i2c_query_ts_info(ts);
+
+	switch (ts->chip_id) {
+	case EKTH3500:
+		if (!error)
+			error = elants_i2c_query_ts_info_ekth(ts);
+		break;
+	case EKTF3624:
+		if (!error)
+			error = elants_i2c_query_ts_info_ektf(ts);
+		break;
+	default:
+		unreachable();
+		break;
+	}
 
 	if (error)
 		ts->iap_mode = ELAN_IAP_RECOVERY;
@@ -1266,6 +1336,9 @@ static int elants_i2c_probe(struct i2c_client *client,
 	ts->client = client;
 	i2c_set_clientdata(client, ts);
 
+	if (client->dev.of_node)
+		ts->chip_id = (uintptr_t)of_device_get_match_data(&client->dev);
+
 	ts->vcc33 = devm_regulator_get(&client->dev, "vcc33");
 	if (IS_ERR(ts->vcc33)) {
 		error = PTR_ERR(ts->vcc33);
@@ -1495,7 +1568,8 @@ MODULE_DEVICE_TABLE(acpi, elants_acpi_id);
 
 #ifdef CONFIG_OF
 static const struct of_device_id elants_of_match[] = {
-	{ .compatible = "elan,ekth3500" },
+	{ .compatible = "elan,ekth3500", .data = (void *)EKTH3500 },
+	{ .compatible = "elan,ektf3624", .data = (void *)EKTF3624 },
 	{ /* sentinel */ }
 };
 MODULE_DEVICE_TABLE(of, elants_of_match);
-- 
2.20.1

Re: [PATCH v7 0/4] input: elants: Support Asus TF300T and Nexus 7 touchscreen

[Michał Mirosław]

On Sat, Sep 19, 2020 at 11:41:19PM +0200, Michał Mirosław wrote:
> This series cleans up the driver a bit and implements changes needed to
> support EKTF3624-based touchscreen used in Asus TF300T, Google Nexus 7
> and similar Tegra3-based tablets.
[...]

Ping? Should I resend? This got only cosmetic fixups and rebases through
last couple of iterations.

Best Regards
Michał Mirosław

Re: [PATCH v7 0/4] input: elants: Support Asus TF300T and Nexus 7 touchscreen

[Dmitry Osipenko]

30.09.2020 20:28, Michał Mirosław пишет:
> On Sat, Sep 19, 2020 at 11:41:19PM +0200, Michał Mirosław wrote:
>> This series cleans up the driver a bit and implements changes needed to
>> support EKTF3624-based touchscreen used in Asus TF300T, Google Nexus 7
>> and similar Tegra3-based tablets.
> [...]
> 
> Ping? Should I resend? This got only cosmetic fixups and rebases through
> last couple of iterations.

+1 We want to get a working touchscreen on our ASUS devices :)

Please consider merging this series. The upstream Nexus 7 DT is already
preapared, now just need the two-line driver change to get the TS working.