[PATCH v10 0/2] Add Novatek NT36xxx touchscreen driver

[PATCH v10 0/2] Add Novatek NT36xxx touchscreen driver

[Konrad Dybcio]

I am taking over this series from Angelo, as he's moved on to other
things, but there are still devices out there (and being made)
utilizing this class of ICs.

This patch series has been tested against the following devices:
 - Sony Xperia 10        (SDM630 Ganges Kirin)
 - Sony Xperia 10 Plus   (SDM636 Ganges Mermaid)

Changes in v2:
- Fixed sparse warnings from lkp kernel test robot

Changes in v3 (as requested by Dmitry Torokhov):
- Using shorthand u16/u32 (sorry for the overlook!)
- Now using more input and touchscreen APIs
- Fixed useless workqueue involvements
- Removed useless locking
- Switched reads and writes to use regmap
- Moved header contents to nt36xxx.c
- Fixed reset gpio handling
- Other cleanups
- P.S.: Thanks, Dmitry!

Changes in v4:
- Fixed regmap read length for CRC_ERR_FLAG final check
- Fixed YAML binding, as requested by Krzysztof Kozlowski

Changes in v5:
- Replaced subsystem maintainer's name with .. mine,
  usage of additionalProperties to unevaluatedProperties
  and a typo fix for reset-gpios as per Rob Herring's review
- Changed compatible string as per Krzysztof K. request
- Renamed the novatek,nt36xxx.yaml file to just nt36xxx.yaml
  in order to now reflect the driver name instead of the DT
  compatible
- Fixed blank line at EOF

Changes in v6:
- Removed include of_gpio.h, added mod_devicetable.h and
  gpio/consumer.h
- Added kerneldoc to relevant functions/enum
- Used traditional patterns for error checking where possible
- Documented calls to usleep/msleep
- Using be16_to_cpu / get_unaligned_be16 where possible
- Added helper for CRC error check on retrieved buffer
- Decreased indentation in the CRC reboot recovery function
- Removed instances of error code sum
- Dropped all likely/unlikely optimization as per request
- Removed redundant reset_gpio checks
- Dropped of_match_ptr and ifdefs for CONFIG_OF

Changes in v7:
- Fixed typo in nt36xxx.c

Changes in v8:
- Fixed typo reset-gpio -> reset-gpios in dt-bindings

Changes in v9:
- Includes are now sorted
- Used proposed sizeof variable instead of sizeof type
- Fixed a return value check for common pattern
- Added NULL check to devm_kasprintf call
- Returning ret on probe function to be consistent

Changes in v10:
- Take over this series from Angelo
- Update Angelo's e-mail address
- Rebase over linux-next
- Pick up tags
- Drop patch adding novatek vendor prefix (it's already there)
- Reword the bindings title and commit title (bindings describe the
  hardware yada yada)
- Solve trivial checkpatch warnings
- Adapt to i2c_probe arguments changing since 2020
- Open-code nt36xxx_mem_map assignments
- Make inline hex lowercase
- Indent nt36xxx_trim_table with tabs
- Add "-i2c" suffix to the compatible, as these chips also can be
  connected over SPI, keep bindings reviews in good faith
- Don't duplicate enum/struct definitions in .c and .h (how did that go
  unnoticed)
- Fix a couple typos
- Use pm_ptr()
- Use consistent whitespacing for defines
- Remove unused defines
- Include nt36xxx.h from nt36xxx.c (........)
- Re-tested on a Sony Xperia 10
Link to v9: https://lore.kernel.org/linux-input/20201028221302.66583-1-kholk11@gmail.com/

--
2.28.0

---
AngeloGioacchino Del Regno (2):
      dt-bindings: touchscreen: Add binding for Novatek NT36xxx ICs
      Input: Add Novatek NT36xxx touchscreen driver

 .../bindings/input/touchscreen/nt36xxx.yaml        |  59 ++
 drivers/input/touchscreen/Kconfig                  |  12 +
 drivers/input/touchscreen/Makefile                 |   1 +
 drivers/input/touchscreen/nt36xxx.c                | 847 +++++++++++++++++++++
 drivers/input/touchscreen/nt36xxx.h                |  89 +++
 5 files changed, 1008 insertions(+)
---
base-commit: 71cd4fc492ec41e4acd85e98bbf7a13753fc1e03
change-id: 20230808-topic-nt36xxx-a41d0c64d5ae

Best regards,
-- 
Konrad Dybcio <konrad.dybcio@linaro.org>

[PATCH v10 1/2] dt-bindings: touchscreen: Add binding for Novatek NT36xxx ICs

[Konrad Dybcio]

From: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>

Add binding for the Novatek NT36xxx series touchscreen ICs.

Reviewed-by: Krzysztof Kozlowski <krzk@kernel.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Signed-off-by: Konrad Dybcio <konrad.dybcio@linaro.org>
---
 .../bindings/input/touchscreen/nt36xxx.yaml        | 59 ++++++++++++++++++++++
 1 file changed, 59 insertions(+)

diff --git a/Documentation/devicetree/bindings/input/touchscreen/nt36xxx.yaml b/Documentation/devicetree/bindings/input/touchscreen/nt36xxx.yaml
new file mode 100644
index 000000000000..d88b149602ef
--- /dev/null
+++ b/Documentation/devicetree/bindings/input/touchscreen/nt36xxx.yaml
@@ -0,0 +1,59 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/input/touchscreen/nt36xxx.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Novatek NT36xxx series touchscreen controller
+
+maintainers:
+  - AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
+
+allOf:
+  - $ref: touchscreen.yaml#
+
+properties:
+  compatible:
+    const: novatek,nt36525-i2c
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+
+  reset-gpios:
+    maxItems: 1
+
+  vdd-supply:
+    description: Power supply regulator for VDD pin
+
+  vio-supply:
+    description: Power supply regulator on VDD-IO pin
+
+unevaluatedProperties: false
+
+required:
+  - compatible
+  - reg
+  - interrupts
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/irq.h>
+    #include <dt-bindings/gpio/gpio.h>
+
+    i2c {
+      #address-cells = <1>;
+      #size-cells = <0>;
+
+      touchscreen@62 {
+        compatible = "novatek,nt36525-i2c";
+        reg = <0x62>;
+        interrupt-parent = <&tlmm>;
+        interrupts = <45 IRQ_TYPE_EDGE_RISING>;
+        reset-gpios = <&tlmm 102 GPIO_ACTIVE_HIGH>;
+      };
+    };
+
+...

-- 
2.41.0

[PATCH v10 2/2] Input: Add Novatek NT36xxx touchscreen driver

[Konrad Dybcio]

From: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>

This is a driver for the Novatek in-cell touch controller and
supports various chips from the NT36xxx family, currently
including NT36525, NT36672A, NT36676F, NT36772 and NT36870.

Functionality like wake gestures and firmware flashing is not
included: I am not aware of any of these DrIC+Touch combo
chips not including a non-volatile memory and it should be
highly unlikely to find one, since the touch firmware is
embedded into the DriverIC one, which is obviously necessary
to drive the display unit.

However, the necessary address for the firmware update
procedure was included into the address table in this driver
so, in the event that someone finds the need to implement it
for a reason or another, it will be pretty straightforward to.

This driver is lightly based on the downstream implementation [1].
[1] https://github.com/Rasenkai/caf-tsoft-Novatek-nt36xxx

Tested-by: Dang Huynh <danct12@riseup.net>
Tested-by: Amit Pundir <amit.pundir@linaro.org>
Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Signed-off-by: Konrad Dybcio <konrad.dybcio@linaro.org>
---
 drivers/input/touchscreen/Kconfig   |  12 +
 drivers/input/touchscreen/Makefile  |   1 +
 drivers/input/touchscreen/nt36xxx.c | 847 ++++++++++++++++++++++++++++++++++++
 drivers/input/touchscreen/nt36xxx.h |  89 ++++
 4 files changed, 949 insertions(+)

diff --git a/drivers/input/touchscreen/Kconfig b/drivers/input/touchscreen/Kconfig
index e3e2324547b9..33182358b6de 100644
--- a/drivers/input/touchscreen/Kconfig
+++ b/drivers/input/touchscreen/Kconfig
@@ -664,6 +664,18 @@ config TOUCHSCREEN_NOVATEK_NVT_TS
 	  To compile this driver as a module, choose M here: the
 	  module will be called novatek-nvt-ts.
 
+config TOUCHSCREEN_NT36XXX
+	tristate "Novatek NT36XXX In-Cell I2C touchscreen controller"
+	depends on I2C
+	help
+	  Say Y here if you have a Novatek NT36xxx series In-Cell
+	  touchscreen connected to your system over I2C.
+
+	  If unsure, say N.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called nt36xxx.
+
 config TOUCHSCREEN_IMAGIS
 	tristate "Imagis touchscreen support"
 	depends on I2C
diff --git a/drivers/input/touchscreen/Makefile b/drivers/input/touchscreen/Makefile
index 62bd24f3ac8e..8f5dee2df20b 100644
--- a/drivers/input/touchscreen/Makefile
+++ b/drivers/input/touchscreen/Makefile
@@ -68,6 +68,7 @@ obj-$(CONFIG_TOUCHSCREEN_MSG2638)	+= msg2638.o
 obj-$(CONFIG_TOUCHSCREEN_MTOUCH)	+= mtouch.o
 obj-$(CONFIG_TOUCHSCREEN_MK712)		+= mk712.o
 obj-$(CONFIG_TOUCHSCREEN_NOVATEK_NVT_TS)	+= novatek-nvt-ts.o
+obj-$(CONFIG_TOUCHSCREEN_NT36XXX)	+= nt36xxx.o
 obj-$(CONFIG_TOUCHSCREEN_HP600)		+= hp680_ts_input.o
 obj-$(CONFIG_TOUCHSCREEN_HP7XX)		+= jornada720_ts.o
 obj-$(CONFIG_TOUCHSCREEN_IPAQ_MICRO)	+= ipaq-micro-ts.o
diff --git a/drivers/input/touchscreen/nt36xxx.c b/drivers/input/touchscreen/nt36xxx.c
new file mode 100644
index 000000000000..07d8902f5932
--- /dev/null
+++ b/drivers/input/touchscreen/nt36xxx.c
@@ -0,0 +1,847 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Driver for Novatek NT36xxx series touchscreens
+ *
+ * Copyright (C) 2010 - 2017 Novatek, Inc.
+ * Copyright (C) 2020 AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
+ */
+
+#include <linux/delay.h>
+#include <linux/gpio/consumer.h>
+#include <linux/i2c.h>
+#include <linux/input/mt.h>
+#include <linux/input/touchscreen.h>
+#include <linux/interrupt.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/regmap.h>
+#include <linux/regulator/consumer.h>
+#include <asm/unaligned.h>
+
+#include "nt36xxx.h"
+
+/* FW Param address */
+#define NT36XXX_FW_ADDR			0x01
+
+/* Misc */
+#define NT36XXX_NUM_SUPPLIES		2
+#define NT36XXX_MAX_RETRIES		5
+#define NT36XXX_MAX_FW_RST_RETRY	50
+
+/* Touch info */
+#define TOUCH_DEFAULT_MAX_WIDTH 	1080
+#define TOUCH_DEFAULT_MAX_HEIGHT	2246
+#define TOUCH_MAX_FINGER_NUM		10
+#define TOUCH_MAX_PRESSURE		1000
+
+/* Point data length */
+#define POINT_DATA_LEN			65
+
+/* Global pages */
+#define NT36XXX_PAGE_CHIP_INFO		0x0001f64e
+#define NT36XXX_PAGE_CRC		0x0003f135
+
+struct nt36xxx_i2c {
+	struct i2c_client *hw_client;
+	struct i2c_client *fw_client;
+	struct regmap *regmap;
+	struct regmap *fw_regmap;
+	struct input_dev *input;
+	struct regulator_bulk_data *supplies;
+	struct gpio_desc *reset_gpio;
+
+	struct mutex lock;
+
+	struct touchscreen_properties prop;
+	struct nt36xxx_fw_info fw_info;
+	struct nt36xxx_abs_object abs_obj;
+
+	const struct nt36xxx_mem_map *mmap;
+};
+
+static const struct nt36xxx_mem_map nt36xxx_memory_maps[] = {
+	[NT36525_IC]  = {
+		.evtbuf_addr = 0x11a00,
+		.pipe0_addr = 0x10000,
+		.pipe1_addr = 0x12000,
+		.flash_csum_addr = 0x14000,
+		.flash_data_addr = 0x14002,
+	},
+	[NT36672A_IC] = {
+		.evtbuf_addr = 0x21c00,
+		.pipe0_addr = 0x20000,
+		.pipe1_addr = 0x23000,
+		.flash_csum_addr = 0x24000,
+		.flash_data_addr = 0x24002,
+	},
+	[NT36676F_IC] = {
+		.evtbuf_addr = 0x11a00,
+		.pipe0_addr = 0x10000,
+		.pipe1_addr = 0x12000,
+		.flash_csum_addr = 0x14000,
+		.flash_data_addr = 0x14002,
+	},
+	[NT36772_IC]  = {
+		.evtbuf_addr = 0x11e00,
+		.pipe0_addr = 0x10000,
+		.pipe1_addr = 0x12000,
+		.flash_csum_addr = 0x14000,
+		.flash_data_addr = 0x14002,
+	},
+	[NT36870_IC]  = {
+		.evtbuf_addr = 0x25000,
+		.pipe0_addr = 0x20000,
+		.pipe1_addr = 0x23000,
+		.flash_csum_addr = 0x24000,
+		.flash_data_addr = 0x24002,
+	},
+};
+
+static const struct nt36xxx_trim_table trim_id_table[] = {
+	{
+		.id = { 0x0a, 0xff, 0xff, 0x72, 0x66, 0x03 },
+		.mask = { 1, 0, 0, 1, 1, 1 },
+		.mapid = NT36672A_IC,
+	},
+	{
+		.id = { 0x55, 0x00, 0xff, 0x00, 0x00, 0x00 },
+		.mask = { 1, 1, 0, 1, 1, 1 },
+		.mapid = NT36772_IC,
+	},
+	{
+		.id = { 0x55, 0x72, 0xff, 0x00, 0x00, 0x00 },
+		.mask = { 1, 1, 0, 1, 1, 1 },
+		.mapid = NT36772_IC,
+	},
+	{
+		.id = { 0xaa, 0x00, 0xff, 0x00, 0x00, 0x00 },
+		.mask = { 1, 1, 0, 1, 1, 1 },
+		.mapid = NT36772_IC,
+	},
+	{
+		.id = { 0xaa, 0x72, 0xff, 0x00, 0x00, 0x00 },
+		.mask = { 1, 1, 0, 1, 1, 1 },
+		.mapid = NT36772_IC,
+	},
+	{
+		.id = { 0xff, 0xff, 0xff, 0x72, 0x67, 0x03 },
+		.mask = { 0, 0, 0, 1, 1, 1 },
+		.mapid = NT36772_IC,
+	},
+	{
+		.id = { 0xff, 0xff, 0xff, 0x70, 0x66, 0x03 },
+		.mask = { 0, 0, 0, 1, 1, 1 },
+		.mapid = NT36772_IC,
+	},
+	{
+		.id = { 0xff, 0xff, 0xff, 0x70, 0x67, 0x03 },
+		.mask = { 0, 0, 0, 1, 1, 1 },
+		.mapid = NT36772_IC,
+	},
+	{
+		.id = { 0xff, 0xff, 0xff, 0x72, 0x66, 0x03 },
+		.mask = { 0, 0, 0, 1, 1, 1 },
+		.mapid = NT36772_IC,
+	},
+	{
+		.id = { 0xff, 0xff, 0xff, 0x25, 0x65, 0x03 },
+		.mask = { 0, 0, 0, 1, 1, 1 },
+		.mapid = NT36772_IC,
+	},
+	{
+		.id = { 0xff, 0xff, 0xff, 0x70, 0x68, 0x03 },
+		.mask = { 0, 0, 0, 1, 1, 1 },
+		.mapid = NT36772_IC,
+	},
+	{
+		.id = { 0xff, 0xff, 0xff, 0x76, 0x66, 0x03 },
+		.mask = { 0, 0, 0, 1, 1, 1 },
+		.mapid = NT36676F_IC,
+	},
+};
+
+/**
+ * nt36xxx_set_page - Set page number for read/write
+ * @ts: Main driver structure
+ *
+ * Return: Always zero for success, negative number for error
+ */
+static int nt36xxx_set_page(struct nt36xxx_i2c *ts, u32 pageaddr)
+{
+	u32 data = cpu_to_be32(pageaddr) >> 8;
+	int ret;
+
+	ret = regmap_noinc_write(ts->fw_regmap, NT36XXX_CMD_SET_PAGE,
+				 &data, sizeof(data));
+	if (ret)
+		return ret;
+
+	usleep_range(100, 200);
+	return ret;
+}
+
+/**
+ * nt36xxx_sw_reset_idle - Warm restart the firmware
+ * @ts: Main driver structure
+ *
+ * This function restarts the running firmware without rebooting to
+ * the bootloader (warm restart)
+ *
+ * Return: Always zero for success, negative number for error
+ */
+static int nt36xxx_sw_reset_idle(struct nt36xxx_i2c *ts)
+{
+	int ret;
+
+	ret = regmap_write(ts->regmap, ts->hw_client->addr,
+			   NT36XXX_CMD_SW_RESET);
+	if (ret)
+		return ret;
+
+	/* Wait until the MCU resets the fw state */
+	usleep_range(15000, 16000);
+	return ret;
+}
+
+/**
+ * nt36xxx_bootloader_reset - Reset MCU to bootloader
+ * @ts: Main driver structure
+ *
+ * Return: Always zero for success, negative number for error
+ */
+static int nt36xxx_bootloader_reset(struct nt36xxx_i2c *ts)
+{
+	int ret;
+
+	ret = regmap_write(ts->regmap, ts->hw_client->addr,
+			   NT36XXX_CMD_BOOTLOADER_RESET);
+	if (ret)
+		return ret;
+
+	/* MCU has to reboot from bootloader - this is the typical boot time */
+	msleep(35);
+	return ret;
+}
+
+/**
+ * nt36xxx_check_reset_state - Check the boot state during reset
+ * @ts: Main driver structure
+ * @fw_state: Enumeration containing firmware states
+ *
+ * Return: Always zero for success, negative number for error
+ */
+static int nt36xxx_check_reset_state(struct nt36xxx_i2c *ts,
+				     enum nt36xxx_fw_state fw_state)
+{
+	u8 buf[2] = { 0 };
+	int ret, retry = NT36XXX_MAX_FW_RST_RETRY;
+
+	do {
+		ret = regmap_noinc_read(ts->fw_regmap,
+					NT36XXX_EVT_RESET_COMPLETE,
+					buf, sizeof(buf));
+		if (likely(ret == 0) &&
+		    (buf[0] >= fw_state) &&
+		    (buf[0] <= NT36XXX_STATE_MAX)) {
+			ret = 0;
+			break;
+		}
+		usleep_range(10000, 11000);
+	} while (--retry);
+
+	if (!retry) {
+		dev_err(&ts->hw_client->dev, "Firmware reset failed.\n");
+		ret = -EBUSY;
+	}
+
+	return ret;
+}
+
+/**
+ * nt36xxx_read_pid - Read Novatek Project ID
+ * @ts: Main driver structure
+ *
+ * Return: Always zero for success, negative number for error
+ */
+static int nt36xxx_read_pid(struct nt36xxx_i2c *ts)
+{
+	__be16 pid;
+	int ret;
+
+	ret = nt36xxx_set_page(ts, ts->mmap->evtbuf_addr);
+	if (ret)
+		return ret;
+
+	ret = regmap_noinc_read(ts->fw_regmap, NT36XXX_EVT_PROJECTID,
+				&pid, sizeof(pid));
+	if (ret < 0)
+		return ret;
+
+	ts->fw_info.nvt_pid = be16_to_cpu(pid);
+	return 0;
+}
+
+/**
+ * __nt36xxx_get_fw_info - Get working params from firmware
+ * @ts: Main driver structure
+ *
+ * Return: Always zero for success, negative number for error
+ */
+static int __nt36xxx_get_fw_info(struct nt36xxx_i2c *ts)
+{
+	struct nt36xxx_fw_info *fwi = &ts->fw_info;
+	u8 buf[11] = { 0 };
+	int ret = 0;
+
+	ret = nt36xxx_set_page(ts, ts->mmap->evtbuf_addr);
+	if (ret)
+		return ret;
+
+	ret = regmap_noinc_read(ts->fw_regmap, NT36XXX_EVT_FWINFO,
+				buf, sizeof(buf));
+	if (ret)
+		return ret;
+
+	fwi->fw_ver = buf[0];
+	fwi->x_num = buf[2];
+	fwi->y_num = buf[3];
+	fwi->abs_x_max = get_unaligned_be16(&buf[4]);
+	fwi->abs_y_max = get_unaligned_be16(&buf[6]);
+	fwi->max_buttons = buf[10];
+
+	/* Check fw info integrity and clear x_num, y_num if broken */
+	if ((buf[0] + buf[1]) != 0xFF) {
+		dev_err(&ts->hw_client->dev,
+			"FW info is broken! fw_ver=0x%02X, ~fw_ver=0x%02X\n",
+			buf[0], buf[1]);
+		fwi->fw_ver = 0;
+		fwi->x_num = 18;
+		fwi->y_num = 32;
+		fwi->abs_x_max = TOUCH_DEFAULT_MAX_WIDTH;
+		fwi->abs_y_max = TOUCH_DEFAULT_MAX_HEIGHT;
+		fwi->max_buttons = 0;
+		return -EINVAL;
+	}
+
+	/* Get Novatek ProjectID */
+	return nt36xxx_read_pid(ts);
+}
+
+static int nt36xxx_get_fw_info(struct nt36xxx_i2c *ts)
+{
+	struct nt36xxx_fw_info *fwi = &ts->fw_info;
+	int i, ret = 0;
+
+	for (i = 0; i < NT36XXX_MAX_RETRIES; i++) {
+		ret = __nt36xxx_get_fw_info(ts);
+		if (ret == 0)
+			break;
+	}
+
+	dev_dbg(&ts->hw_client->dev,
+		"FW Info: PID=0x%x, ver=0x%x res=%ux%u max=%ux%u buttons=%u",
+		fwi->nvt_pid, fwi->fw_ver, fwi->x_num, fwi->y_num,
+		fwi->abs_x_max, fwi->abs_y_max, fwi->max_buttons);
+
+	return ret;
+}
+
+/**
+ * nt36xxx_report - Report touch events
+ * @ts: Main driver structure
+ *
+ * Return: Always zero for success, negative number for error
+ */
+static void nt36xxx_report(struct nt36xxx_i2c *ts)
+{
+	struct nt36xxx_abs_object *obj = &ts->abs_obj;
+	struct input_dev *input = ts->input;
+	u8 input_id = 0;
+	u8 point[POINT_DATA_LEN + 1] = { 0 };
+	unsigned int ppos = 0;
+	int i, ret, finger_cnt = 0;
+
+	mutex_lock(&ts->lock);
+
+	ret = regmap_noinc_read(ts->fw_regmap, NT36XXX_EVT_REPORT,
+				point, sizeof(point));
+	if (ret < 0) {
+		dev_err(&ts->hw_client->dev,
+			"Cannot read touch point data: %d\n", ret);
+		goto xfer_error;
+	}
+
+	for (i = 0; i < TOUCH_MAX_FINGER_NUM; i++) {
+		ppos = 6 * i;
+		input_id = point[ppos + 0] >> 3;
+		if ((input_id == 0) || (input_id > TOUCH_MAX_FINGER_NUM))
+			continue;
+
+		if (((point[ppos] & 0x07) == 0x01) ||
+		    ((point[ppos] & 0x07) == 0x02)) {
+			obj->x = (point[ppos + 1] << 4) +
+				 (point[ppos + 3] >> 4);
+			obj->y = (point[ppos + 2] << 4) +
+				 (point[ppos + 3] & 0xf);
+			if ((obj->x > ts->prop.max_x) ||
+			    (obj->y > ts->prop.max_y))
+				continue;
+
+			obj->tm = point[ppos + 4];
+			if (obj->tm == 0)
+				obj->tm = 1;
+
+			obj->z = point[ppos + 5];
+			if (i < 2) {
+				obj->z += point[i + 63] << 8;
+				if (obj->z > TOUCH_MAX_PRESSURE)
+					obj->z = TOUCH_MAX_PRESSURE;
+			}
+
+			if (obj->z == 0)
+				obj->z = 1;
+
+			input_mt_slot(input, input_id - 1);
+			input_mt_report_slot_state(input,
+						   MT_TOOL_FINGER, true);
+			touchscreen_report_pos(input, &ts->prop, obj->x,
+					       obj->y, true);
+
+			input_report_abs(input, ABS_MT_TOUCH_MAJOR, obj->tm);
+			input_report_abs(input, ABS_MT_PRESSURE, obj->z);
+
+			finger_cnt++;
+		}
+	}
+	input_mt_sync_frame(input);
+	input_sync(input);
+
+xfer_error:
+	enable_irq(ts->hw_client->irq);
+
+	mutex_unlock(&ts->lock);
+}
+
+static irqreturn_t nt36xxx_i2c_irq_handler(int irq, void *dev_id)
+{
+	struct nt36xxx_i2c *ts = dev_id;
+
+	disable_irq_nosync(ts->hw_client->irq);
+	nt36xxx_report(ts);
+
+	return IRQ_HANDLED;
+}
+
+static bool nt36xxx_in_crc_reboot_loop(u8 *buf)
+{
+	return ((buf[0] == 0xfc) && (buf[1] == 0xfc) && (buf[2] == 0xfc)) ||
+	       ((buf[0] == 0xff) && (buf[1] == 0xff) && (buf[2] == 0xff));
+}
+
+/**
+ * nt36xxx_stop_crc_reboot - Stop CRC reboot loop and warm-reboot the firmware
+ * @ts: Main driver structure
+ *
+ * Return: Always zero for success, negative number for error
+ */
+static int nt36xxx_stop_crc_reboot(struct nt36xxx_i2c *ts)
+{
+	u8 buf[3] = { 0 };
+	u8 val;
+	int ret, retry = NT36XXX_MAX_RETRIES;
+
+	/* Read dummy buffer to check CRC fail reboot is happening or not */
+
+	/* Change I2C index to prevent getting 0xFF, but not 0xFC */
+	ret = nt36xxx_set_page(ts, NT36XXX_PAGE_CHIP_INFO);
+	if (ret) {
+		dev_dbg(&ts->hw_client->dev,
+			"CRC reset failed: Cannot select page.\n");
+		return ret;
+	}
+
+	/* If ChipID command returns 0xFC or 0xFF, the MCU is in CRC reboot */
+	ret = regmap_noinc_read(ts->fw_regmap, NT36XXX_EVT_CHIPID,
+				buf, sizeof(buf));
+	if (ret)
+		return ret;
+
+	if (!nt36xxx_in_crc_reboot_loop(buf))
+		return 0;
+
+	/* IC is in CRC fail reboot loop, needs to be stopped! */
+	do {
+		/* Special reset-idle sequence for CRC failure */
+		ret = regmap_write(ts->regmap, ts->hw_client->addr,
+				   NT36XXX_CMD_SW_RESET);
+		if (ret)
+			dev_dbg(&ts->hw_client->dev,
+				"SW Reset 1 failed: may not recover\n");
+
+		ret = regmap_write(ts->regmap, ts->hw_client->addr,
+				   NT36XXX_CMD_SW_RESET);
+		if (ret)
+			dev_dbg(&ts->hw_client->dev,
+				"SW Reset 2 failed: may not recover\n");
+		usleep_range(1000, 1100);
+
+		/* Clear CRC_ERR_FLAG */
+		ret = nt36xxx_set_page(ts, NT36XXX_PAGE_CRC);
+		if (ret)
+			continue;
+
+		val = 0xa5;
+		ret = regmap_raw_write(ts->fw_regmap, NT36XXX_EVT_CRC,
+				       &val, sizeof(val));
+		if (ret)
+			continue;
+
+		/* Check CRC_ERR_FLAG */
+		ret = nt36xxx_set_page(ts, NT36XXX_PAGE_CRC);
+		if (ret)
+			continue;
+
+		ret = regmap_noinc_read(ts->fw_regmap, NT36XXX_EVT_CRC,
+					&buf, sizeof(buf));
+		if (ret)
+			continue;
+
+		if (buf[0] == 0xa5)
+			break;
+	} while (--retry);
+
+	if (retry == 0) {
+		dev_err(&ts->hw_client->dev,
+			"CRC reset failed: buf=0x%2ph\n", buf);
+	}
+
+	return ret;
+}
+
+/**
+ * nt36xxx_i2c_chip_version_init - Detect Novatek NT36xxx family IC
+ * @ts: Main driver structure
+ *
+ * This function reads the ChipID from the IC and sets the right
+ * memory map for the detected chip.
+ *
+ * Return: Always zero for success, negative number for error
+ */
+static int nt36xxx_i2c_chip_version_init(struct nt36xxx_i2c *ts)
+{
+	u8 buf[7] = { 0 };
+	int retry = NT36XXX_MAX_RETRIES;
+	int sz = sizeof(trim_id_table) / sizeof(struct nt36xxx_trim_table);
+	int i, list, mapid, ret;
+
+	ret = nt36xxx_bootloader_reset(ts);
+	if (ret) {
+		dev_err(&ts->hw_client->dev, "Can't reset the nvt IC\n");
+		return ret;
+	}
+
+	do {
+		ret = nt36xxx_sw_reset_idle(ts);
+		if (ret)
+			continue;
+
+		ret = regmap_write(ts->regmap, ts->hw_client->addr, NT36XXX_CMD_UNLOCK);
+		if (ret)
+			continue;
+		usleep_range(10000, 11000);
+
+		ret = nt36xxx_set_page(ts, NT36XXX_PAGE_CHIP_INFO);
+		if (ret)
+			continue;
+
+		memset(buf, 0, ARRAY_SIZE(buf));
+		ret = regmap_noinc_read(ts->fw_regmap, NT36XXX_EVT_CHIPID,
+					buf, sizeof(buf));
+		if (ret)
+			continue;
+
+		/* Compare read chip id with trim list */
+		for (list = 0; list < sz; list++) {
+			/* Compare each not masked byte */
+			for (i = 0; i < NT36XXX_ID_LEN_MAX; i++) {
+				if (trim_id_table[list].mask[i] &&
+				    buf[i] != trim_id_table[list].id[i])
+					break;
+			}
+
+			if (i == NT36XXX_ID_LEN_MAX) {
+				mapid = trim_id_table[list].mapid;
+				ts->mmap = &nt36xxx_memory_maps[mapid];
+				return 0;
+			}
+
+			ts->mmap = NULL;
+			ret = -ENOENT;
+		}
+
+		/* Stop CRC check to prevent IC auto reboot */
+		if (nt36xxx_in_crc_reboot_loop(buf)) {
+			ret = nt36xxx_stop_crc_reboot(ts);
+			if (ret)
+				continue;
+		}
+
+		usleep_range(10000, 11000);
+	} while (--retry);
+
+	return ret;
+}
+
+static const struct regmap_config nt36xxx_i2c_regmap_hw_config = {
+	.name = "nt36xxx_i2c_hw",
+	.reg_bits = 8,
+	.val_bits = 8,
+	.cache_type = REGCACHE_NONE,
+};
+
+static const struct regmap_config nt36xxx_i2c_regmap_fw_config = {
+	.name = "nt36xxx_i2c_fw",
+	.reg_bits = 8,
+	.val_bits = 8,
+	.cache_type = REGCACHE_NONE,
+};
+
+static void nt36xxx_disable_regulators(void *data)
+{
+	struct nt36xxx_i2c *ts = data;
+
+	regulator_bulk_disable(NT36XXX_NUM_SUPPLIES, ts->supplies);
+}
+
+static int nt36xxx_i2c_probe(struct i2c_client *hw_client)
+{
+	struct nt36xxx_i2c *ts;
+	struct input_dev *input;
+	int ret;
+
+	if (!i2c_check_functionality(hw_client->adapter, I2C_FUNC_I2C)) {
+		dev_err(&hw_client->dev, "i2c_check_functionality error\n");
+		return -EIO;
+	}
+
+	if (!hw_client->irq) {
+		dev_err(&hw_client->dev, "No irq specified\n");
+		return -EINVAL;
+	}
+
+	ts = devm_kzalloc(&hw_client->dev, sizeof(*ts), GFP_KERNEL);
+	if (!ts)
+		return -ENOMEM;
+
+	ts->supplies = devm_kcalloc(&hw_client->dev,
+				    NT36XXX_NUM_SUPPLIES,
+				    sizeof(*ts->supplies),
+				    GFP_KERNEL);
+	if (!ts->supplies)
+		return -ENOMEM;
+
+	input = devm_input_allocate_device(&hw_client->dev);
+	if (!input)
+		return -ENOMEM;
+
+	ts->fw_client = i2c_new_dummy_device(hw_client->adapter,
+					     NT36XXX_FW_ADDR);
+	if (IS_ERR(ts->fw_client)) {
+		dev_err(&hw_client->dev, "Cannot add FW I2C device\n");
+		return PTR_ERR(ts->fw_client);
+	}
+
+	ts->hw_client = hw_client;
+	ts->input = input;
+	i2c_set_clientdata(ts->hw_client, ts);
+	i2c_set_clientdata(ts->fw_client, ts);
+
+	ts->reset_gpio = devm_gpiod_get_optional(&hw_client->dev, "reset",
+						 GPIOD_OUT_HIGH);
+	if (IS_ERR(ts->reset_gpio))
+		return PTR_ERR(ts->reset_gpio);
+	gpiod_set_consumer_name(ts->reset_gpio, "nt36xxx reset");
+
+	/* These supplies are optional */
+	ts->supplies[0].supply = "vdd";
+	ts->supplies[1].supply = "vio";
+	ret = devm_regulator_bulk_get(&hw_client->dev,
+				      NT36XXX_NUM_SUPPLIES,
+				      ts->supplies);
+	if (ret)
+		return dev_err_probe(&hw_client->dev, ret,
+				     "Cannot get supplies: %d\n", ret);
+
+	ts->regmap = devm_regmap_init_i2c(ts->hw_client,
+					  &nt36xxx_i2c_regmap_hw_config);
+	if (IS_ERR(ts->regmap)) {
+		dev_err(&hw_client->dev, "regmap (hw-addr) init failed\n");
+		return PTR_ERR(ts->regmap);
+	}
+
+	ts->fw_regmap = devm_regmap_init_i2c(ts->fw_client,
+					     &nt36xxx_i2c_regmap_fw_config);
+	if (IS_ERR(ts->fw_regmap)) {
+		dev_err(&hw_client->dev, "regmap (fw-addr) init failed\n");
+		return PTR_ERR(ts->fw_regmap);
+	}
+
+	ret = regulator_bulk_enable(NT36XXX_NUM_SUPPLIES, ts->supplies);
+	if (ret)
+		return ret;
+
+	usleep_range(10000, 11000);
+
+	ret = devm_add_action_or_reset(&hw_client->dev,
+				       nt36xxx_disable_regulators, ts);
+	if (ret)
+		return ret;
+
+	mutex_init(&ts->lock);
+
+	/* Set memory maps for the specific chip version */
+	ret = nt36xxx_i2c_chip_version_init(ts);
+	if (ret) {
+		dev_err(&hw_client->dev, "Failed to check chip version\n");
+		return ret;
+	}
+
+	/* Reset the MCU */
+	ret = nt36xxx_bootloader_reset(ts);
+	if (ret < 0)
+		return ret;
+
+	/* Check and eventually wait until the MCU goes in reset state */
+	ret = nt36xxx_check_reset_state(ts, NT36XXX_STATE_INIT);
+	if (ret < 0)
+		return ret;
+
+	/* Get information from the TS firmware */
+	ret = nt36xxx_get_fw_info(ts);
+	if (ret < 0)
+		return ret;
+
+	input->phys = devm_kasprintf(&hw_client->dev, GFP_KERNEL,
+				     "%s/input0", dev_name(&hw_client->dev));
+	if (!input->phys)
+		return -ENOMEM;
+
+	input->name = "Novatek NT36XXX Touchscreen";
+	input->id.bustype = BUS_I2C;
+	input->dev.parent = &hw_client->dev;
+
+	__set_bit(EV_KEY, input->evbit);
+	__set_bit(EV_ABS, input->evbit);
+	input_set_capability(input, EV_KEY, BTN_TOUCH);
+
+	ret = input_mt_init_slots(input, TOUCH_MAX_FINGER_NUM,
+				  INPUT_MT_DIRECT | INPUT_MT_DROP_UNUSED);
+	if (ret) {
+		dev_err(&hw_client->dev, "Cannot init MT slots (%d)\n", ret);
+		return ret;
+	}
+
+	input_set_abs_params(input, ABS_MT_PRESSURE, 0,
+			     TOUCH_MAX_PRESSURE, 0, 0);
+	input_set_abs_params(input, ABS_MT_TOUCH_MAJOR, 0, 255, 0, 0);
+
+	input_set_abs_params(input, ABS_MT_POSITION_X, 0,
+			     ts->fw_info.abs_x_max - 1, 0, 0);
+	input_set_abs_params(input, ABS_MT_POSITION_Y, 0,
+			     ts->fw_info.abs_y_max - 1, 0, 0);
+
+	/* Override the firmware defaults, if needed */
+	touchscreen_parse_properties(input, true, &ts->prop);
+
+	input_set_drvdata(input, ts);
+
+	ret = input_register_device(ts->input);
+	if (ret) {
+		dev_err(&hw_client->dev, "Failed to register input device: %d\n",
+			ret);
+		return ret;
+	}
+
+	ret = devm_request_threaded_irq(&hw_client->dev, hw_client->irq, NULL,
+					nt36xxx_i2c_irq_handler, IRQF_ONESHOT,
+					hw_client->name, ts);
+	if (ret) {
+		dev_err(&hw_client->dev, "request irq failed: %d\n", ret);
+		return ret;
+	}
+
+	return ret;
+}
+
+static int __maybe_unused nt36xxx_i2c_suspend(struct device *dev)
+{
+	struct nt36xxx_i2c *ts = i2c_get_clientdata(to_i2c_client(dev));
+	int ret;
+
+	disable_irq(ts->hw_client->irq);
+
+	ret = regmap_write(ts->fw_regmap, NT36XXX_EVT_HOST_CMD,
+			   NT36XXX_CMD_ENTER_SLEEP);
+	if (ret) {
+		dev_err(&ts->hw_client->dev, "Cannot enter suspend!!\n");
+		return ret;
+	}
+
+	gpiod_set_value(ts->reset_gpio, 1);
+
+	return 0;
+}
+
+static int __maybe_unused nt36xxx_i2c_resume(struct device *dev)
+{
+	struct nt36xxx_i2c *ts = i2c_get_clientdata(to_i2c_client(dev));
+	int ret;
+
+	mutex_lock(&ts->lock);
+
+	gpiod_set_value(ts->reset_gpio, 0);
+
+	/* Reboot the MCU (also recalibrates the TS) */
+	ret = nt36xxx_bootloader_reset(ts);
+	if (ret < 0)
+		goto end;
+
+	ret = nt36xxx_check_reset_state(ts, NT36XXX_STATE_REK);
+	if (ret < 0)
+		goto end;
+
+	enable_irq(ts->hw_client->irq);
+end:
+	mutex_unlock(&ts->lock);
+	return ret;
+}
+
+static SIMPLE_DEV_PM_OPS(nt36xxx_i2c_pm,
+			 nt36xxx_i2c_suspend, nt36xxx_i2c_resume);
+
+static const struct of_device_id nt36xxx_of_match[] = {
+	{ .compatible = "novatek,nt36525-i2c" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, nt36xxx_of_match);
+
+static const struct i2c_device_id nt36xxx_i2c_ts_id[] = {
+	{ "NVT-ts", 0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, nt36xxx_i2c_ts_id);
+
+static struct i2c_driver nt36xxx_i2c_ts_driver = {
+	.driver = {
+		.name	= "nt36xxx_ts",
+		.pm	= pm_ptr(&nt36xxx_i2c_pm),
+		.of_match_table = nt36xxx_of_match,
+	},
+	.id_table	= nt36xxx_i2c_ts_id,
+	.probe		= nt36xxx_i2c_probe,
+};
+module_i2c_driver(nt36xxx_i2c_ts_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Novatek NT36XXX Touchscreen Driver");
+MODULE_AUTHOR("AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>");
diff --git a/drivers/input/touchscreen/nt36xxx.h b/drivers/input/touchscreen/nt36xxx.h
new file mode 100644
index 000000000000..66ac9b2886ac
--- /dev/null
+++ b/drivers/input/touchscreen/nt36xxx.h
@@ -0,0 +1,89 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2010 - 2017 Novatek, Inc.
+ * Copyright (C) 2020 AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
+ */
+
+#ifndef NT36XXX_H
+#define NT36XXX_H
+
+/* Number of bytes for chip identification */
+#define NT36XXX_ID_LEN_MAX		6
+
+struct nt36xxx_abs_object {
+	u16 x;
+	u16 y;
+	u16 z;
+	u8 tm;
+};
+
+struct nt36xxx_fw_info {
+	u8 fw_ver;
+	u8 x_num;
+	u8 y_num;
+	u8 max_buttons;
+	u16 abs_x_max;
+	u16 abs_y_max;
+	u16 nvt_pid;
+};
+
+struct nt36xxx_mem_map {
+	u32 evtbuf_addr;
+	u32 pipe0_addr;
+	u32 pipe1_addr;
+	u32 flash_csum_addr;
+	u32 flash_data_addr;
+};
+
+enum nt36xxx_chips {
+	NT36525_IC = 0,
+	NT36672A_IC,
+	NT36676F_IC,
+	NT36772_IC,
+	NT36870_IC,
+	NTMAX_IC,
+};
+
+struct nt36xxx_trim_table {
+	u8 id[NT36XXX_ID_LEN_MAX];
+	u8 mask[NT36XXX_ID_LEN_MAX];
+	enum nt36xxx_chips mapid;
+};
+
+/**
+ * enum nt36xxx_fw_state - Firmware state
+ * @NT36XXX_STATE_INIT: IC Reset
+ * @NT36XXX_STATE_REK: ReK baseline
+ * @NT36XXX_STATE_REK_FINISH: Baseline is ready
+ * @NT36XXX_STATE_NORMAL_RUN: Firmware is running
+ */
+enum nt36xxx_cmds {
+	NT36XXX_CMD_ENTER_SLEEP = 0x11,
+	NT36XXX_CMD_ENTER_WKUP_GESTURE = 0x13,
+	NT36XXX_CMD_UNLOCK = 0x35,
+	NT36XXX_CMD_BOOTLOADER_RESET = 0x69,
+	NT36XXX_CMD_SW_RESET = 0xa5,
+	NT36XXX_CMD_SET_PAGE = 0xff,
+};
+
+enum nt36xxx_fw_state {
+	NT36XXX_STATE_INIT = 0xa0,	/* IC reset */
+	NT36XXX_STATE_REK,		/* ReK baseline */
+	NT36XXX_STATE_REK_FINISH,	/* Baseline is ready */
+	NT36XXX_STATE_NORMAL_RUN,	/* Normal run */
+	NT36XXX_STATE_MAX = 0xaf
+};
+
+enum nt36xxx_events {
+	NT36XXX_EVT_REPORT = 0x00,
+	NT36XXX_EVT_CRC = 0x35,
+	NT36XXX_EVT_CHIPID = 0x4e,
+	NT36XXX_EVT_HOST_CMD = 0x50,
+	NT36XXX_EVT_HS_OR_SUBCMD = 0x51,	/* Handshake or subcommand byte */
+	NT36XXX_EVT_RESET_COMPLETE = 0x60,
+	NT36XXX_EVT_FWINFO = 0x78,
+	NT36XXX_EVT_PROJECTID = 0x9a,
+
+};
+
+#endif

-- 
2.41.0

Re: [PATCH v10 2/2] Input: Add Novatek NT36xxx touchscreen driver

[Joel Selvaraj]

Hi Konrad Dybcio,

On 8/8/23 18:38, Konrad Dybcio wrote:
> From: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
> 
> This is a driver for the Novatek in-cell touch controller and
> supports various chips from the NT36xxx family, currently
> including NT36525, NT36672A, NT36676F, NT36772 and NT36870.

In kernel v6.4, a basic novatek touchscreen driver was introduced [1].
I was able to tweak IT a bit (add devicetree compatible, regulator 
support, remove chip id hardcode) and get it properly working in my 
Xiaomi Poco F1 which has Novatek NT36672A touchscreen. Probably the 
other ICs will also work. So, do we really need a separate touchscreen 
driver? Maybe the existing one can be improved to add more features if 
needed?

Personally I have been looking forward to the v10 of this patchseries :) 
Thanks for working on this! But, yeah, we need to decide if we need this 
to be a separate driver.

Link: 
https://lore.kernel.org/all/20230326212308.55730-1-hdegoede@redhat.com/

Regards
Joel Selvaraj

Re: [PATCH v10 2/2] Input: Add Novatek NT36xxx touchscreen driver

[Konrad Dybcio]

On 16.08.2023 03:09, Joel Selvaraj wrote:
> Hi Konrad Dybcio,
> 
> On 8/8/23 18:38, Konrad Dybcio wrote:
>> From: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
>>
>> This is a driver for the Novatek in-cell touch controller and
>> supports various chips from the NT36xxx family, currently
>> including NT36525, NT36672A, NT36676F, NT36772 and NT36870.
> 
> In kernel v6.4, a basic novatek touchscreen driver was introduced [1].
> I was able to tweak IT a bit (add devicetree compatible, regulator support, remove chip id hardcode) and get it properly working in my Xiaomi Poco F1 which has Novatek NT36672A touchscreen. Probably the other ICs will also work. So, do we really need a separate touchscreen driver? Maybe the existing one can be improved to add more features if needed?
Do you have your end outcome somewhere?

I can take a look and compare if anything's missing..


> 
> Personally I have been looking forward to the v10 of this patchseries :) Thanks for working on this! But, yeah, we need to decide if we need this to be a separate driver.
We'll see, I was hoping I could add firmware loading, SPI transport and
eventually pen support..

Konrad

Re: [PATCH v10 2/2] Input: Add Novatek NT36xxx touchscreen driver

[Joel Selvaraj]

Hi Konrad,

On 8/16/23 12:36, Konrad Dybcio wrote:
> Do you have your end outcome somewhere?

Here is the driver changes on top of upstream 
"drivers/input/touchscreen/novatek-nvt-ts.c"

Link: 
https://gitlab.com/sdm845-mainline/linux/-/commit/d2f7702a7f6a72eaf2655840036668398942c194

and here is how I specified it in the Poco F1 dts:

Link: 
https://gitlab.com/sdm845-mainline/linux/-/commit/4dd6e4578cc737d2584c7f9657f9f185effe9035

Regards
Joel Selvaraj

Re: [PATCH v10 2/2] Input: Add Novatek NT36xxx touchscreen driver

[Konrad Dybcio]

On 18.08.2023 00:17, Joel Selvaraj wrote:
> Hi Konrad,
> 
> On 8/16/23 12:36, Konrad Dybcio wrote:
>> Do you have your end outcome somewhere?
> 
> Here is the driver changes on top of upstream "drivers/input/touchscreen/novatek-nvt-ts.c"
> 
> Link: https://gitlab.com/sdm845-mainline/linux/-/commit/d2f7702a7f6a72eaf2655840036668398942c194
> 
> and here is how I specified it in the Poco F1 dts:
> 
> Link: https://gitlab.com/sdm845-mainline/linux/-/commit/4dd6e4578cc737d2584c7f9657f9f185effe9035
> 
> Regards
> Joel Selvaraj
Hm, the one present in mainline is quite lackluster compared to this
one that Angelo made..

Konrad