[PATCH v6 0/5] input: elants: Support Asus TF300T touchscreen

[PATCH v6 0/5] input: elants: Support Asus TF300T touchscreen

[Michał Mirosław]

This series cleans up the driver a bit and implements changes needed to
support EKTF3624-based touchscreen used in Asus TF300T 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)

---

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

Michał Mirosław (4):
  input: elants: document some registers and values
  input: elants: support old touch report format
  input: elants: read touchscreen size for EKTF3624
  input: mt: cleanup open-coded __set_bit()

 drivers/input/input-mt.c               |   2 +-
 drivers/input/touchscreen/elants_i2c.c | 149 +++++++++++++++++++++----
 2 files changed, 128 insertions(+), 23 deletions(-)

-- 
2.20.1

[PATCH v6 1/5] input: elants: document some registers and values

[Michał Mirosław]

Add information found in downstream kernels, to make the code less
magic. Fix comment spelling along the way.

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 5477a5718202..fa4a2f6b69c6 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
 
@@ -268,8 +272,8 @@ 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);
@@ -1382,7 +1386,9 @@ 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;
 
@@ -1419,7 +1425,9 @@ 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 v6 2/5] 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 fa4a2f6b69c6..ba1816d08530 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
@@ -849,7 +850,8 @@ 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;
@@ -862,7 +864,8 @@ 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) ?
@@ -876,8 +879,16 @@ 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);
@@ -909,7 +920,8 @@ 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);
 
@@ -923,7 +935,7 @@ 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)
@@ -981,7 +993,8 @@ 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:
@@ -994,17 +1007,18 @@ 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 v6 3/5] 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 ba1816d08530..d4c60c9fc38b 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		0xE0
 #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
@@ -156,6 +162,7 @@ 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;
@@ -433,7 +440,58 @@ 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;
@@ -584,8 +642,20 @@ 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;
@@ -1262,6 +1332,9 @@ 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);
@@ -1489,7 +1562,8 @@ 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

[PATCH v6 5/5] input: mt: cleanup open-coded __set_bit()

[Michał Mirosław]

Replace open-coded __set_bit() with the function.

Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
---
 drivers/input/input-mt.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/input/input-mt.c b/drivers/input/input-mt.c
index a81e14148407..f699538bdac4 100644
--- a/drivers/input/input-mt.c
+++ b/drivers/input/input-mt.c
@@ -16,7 +16,7 @@ static void copy_abs(struct input_dev *dev, unsigned int dst, unsigned int src)
 	if (dev->absinfo && test_bit(src, dev->absbit)) {
 		dev->absinfo[dst] = dev->absinfo[src];
 		dev->absinfo[dst].fuzz = 0;
-		dev->absbit[BIT_WORD(dst)] |= BIT_MASK(dst);
+		__set_bit(dst, dev->absbit);
 	}
 }
 
-- 
2.20.1

[PATCH v6 4/5] 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 d4c60c9fc38b..c90dc34742e5 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
@@ -1048,7 +1057,6 @@ 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:
@@ -1068,6 +1076,7 @@ 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

Re: [PATCH v6 5/5] input: mt: cleanup open-coded __set_bit()

[Dmitry Torokhov]

On Mon, Jul 13, 2020 at 02:24:55AM +0200, Michał Mirosław wrote:
> Replace open-coded __set_bit() with the function.
> 
> Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>

Applied, thank you.

-- 
Dmitry

Re: [PATCH v6 5/5] input: mt: cleanup open-coded __set_bit()

[Dmitry Osipenko]

16.07.2020 03:30, Dmitry Torokhov пишет:
> On Mon, Jul 13, 2020 at 02:24:55AM +0200, Michał Mirosław wrote:
>> Replace open-coded __set_bit() with the function.
>>
>> Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
> 
> Applied, thank you.
> 

Hello, Dmitry!

Could you please let us know how we could proceed with applying the rest
of the patches?

The device-tree for Nexus 7 2012 [1] has been merged into upcoming v5.9
and I'd want to add the touchscreen support.

[1]
https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/?id=2720008f4239cf36d57b8d0b3cb2a49d4368a378

The missing elants_i2c driver functionality doesn't really block making
a device-tree change since elants_i2c.yaml DT binding already supports
the ektf3624 TS model, but will be nice to get a full featured support.

Thanks in advance!