[PATCH v3 0/6] Add touch-keys support to the Zinitix touch driver

[PATCH v3 0/6] Add touch-keys support to the Zinitix touch driver

[Nikita Travkin]

This series adds support for the touch-keys that can be present on some
touchscreen configurations, adds the compatible for bt532 and fixes a
small race condition bug in the driver probe function.

I also pick up the series that converts the dt bindings to yaml
initially submitted by Linus Walleij in [1].
I made some minor changes to those patches:
 - Fixed dt_schema_check error
 - Adressed the review comments from Dmitry on the original series

[1] https://lore.kernel.org/linux-input/20210625113435.2539282-1-linus.walleij@linaro.org/

Changes in v2:
- Use input.yaml in the dt binding for the touchkey
- Add missing le16_to_cpu()
Changes in v3:
- Add yet another missing le16_to_cpu()

Linus Walleij (2):
  dt-bindings: input/ts/zinitix: Convert to YAML, fix and extend
  Input: zinitix - Handle proper supply names

Nikita Travkin (4):
  input: zinitix: Make sure the IRQ is allocated before it gets enabled
  input: zinitix: Add compatible for bt532
  dt-bindings: input: zinitix: Document touch-keys support
  input: zinitix: Add touchkey support

 .../input/touchscreen/zinitix,bt400.yaml      | 125 ++++++++++++++++++
 .../bindings/input/touchscreen/zinitix.txt    |  40 ------
 drivers/input/touchscreen/zinitix.c           | 101 +++++++++++---
 3 files changed, 209 insertions(+), 57 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/input/touchscreen/zinitix,bt400.yaml
 delete mode 100644 Documentation/devicetree/bindings/input/touchscreen/zinitix.txt

-- 
2.30.2

[PATCH v3 1/6] input: zinitix: Make sure the IRQ is allocated before it gets enabled

[Nikita Travkin]

Since irq request is the last thing in the driver probe, it happens
later than the input device registration. This means that there is a
small time window where if the open method is called the driver will
attempt to enable not yet available irq.

Fix that by moving the irq request before the input device registration.

Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Fixes: 26822652c85e ("Input: add zinitix touchscreen driver")
Signed-off-by: Nikita Travkin <nikita@trvn.ru>
---
 drivers/input/touchscreen/zinitix.c | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/drivers/input/touchscreen/zinitix.c b/drivers/input/touchscreen/zinitix.c
index b8d901099378..1e70b8d2a8d7 100644
--- a/drivers/input/touchscreen/zinitix.c
+++ b/drivers/input/touchscreen/zinitix.c
@@ -488,6 +488,15 @@ static int zinitix_ts_probe(struct i2c_client *client)
 		return error;
 	}
 
+	error = devm_request_threaded_irq(&client->dev, client->irq,
+					  NULL, zinitix_ts_irq_handler,
+					  IRQF_ONESHOT | IRQF_NO_AUTOEN,
+					  client->name, bt541);
+	if (error) {
+		dev_err(&client->dev, "Failed to request IRQ: %d\n", error);
+		return error;
+	}
+
 	error = zinitix_init_input_dev(bt541);
 	if (error) {
 		dev_err(&client->dev,
@@ -513,15 +522,6 @@ static int zinitix_ts_probe(struct i2c_client *client)
 		return -EINVAL;
 	}
 
-	error = devm_request_threaded_irq(&client->dev, client->irq,
-					  NULL, zinitix_ts_irq_handler,
-					  IRQF_ONESHOT | IRQF_NO_AUTOEN,
-					  client->name, bt541);
-	if (error) {
-		dev_err(&client->dev, "Failed to request IRQ: %d\n", error);
-		return error;
-	}
-
 	return 0;
 }
 
-- 
2.30.2

[PATCH v3 2/6] dt-bindings: input/ts/zinitix: Convert to YAML, fix and extend

[Nikita Travkin]

From: Linus Walleij <linus.walleij@linaro.org>

This converts the Zinitix BT4xx and BT5xx touchscreen bindings to YAML, fix
them up a bit and extends them.

We list all the existing BT4xx and BT5xx components with compatible strings.
These are all similar, use the same bindings and work in similar ways.

We rename the supplies from the erroneous vdd/vddo to the actual supply
names vcca/vdd as specified on the actual component. It is long established
that supplies shall be named after the supply pin names of a component.
The confusion probably stems from that in a certain product the rails to the
component were named vdd/vddo. Drop some notes on how OS implementations should
avoid confusion by first looking for vddo, and if that exists assume the
legacy binding pair and otherwise use vcca/vdd.

Add reset-gpios as sometimes manufacturers pulls a GPIO line to the reset
line on the chip.

Add optional touchscreen-fuzz-x and touchscreen-fuzz-y properties.

Cc: Mark Brown <broonie@kernel.org>
Cc: Michael Srba <Michael.Srba@seznam.cz>
Cc: phone-devel@vger.kernel.org
Cc: devicetree@vger.kernel.org
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
[Fixed dt_schema_check]
Signed-off-by: Nikita Travkin <nikita@trvn.ru>
---
This patch was previously submitted here:
https://lore.kernel.org/linux-input/20210625113435.2539282-1-linus.walleij@linaro.org/

Changes since the original patch:
 - Use enum for compatible list instead of oneOf + const
---
 .../input/touchscreen/zinitix,bt400.yaml      | 115 ++++++++++++++++++
 .../bindings/input/touchscreen/zinitix.txt    |  40 ------
 2 files changed, 115 insertions(+), 40 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/input/touchscreen/zinitix,bt400.yaml
 delete mode 100644 Documentation/devicetree/bindings/input/touchscreen/zinitix.txt

diff --git a/Documentation/devicetree/bindings/input/touchscreen/zinitix,bt400.yaml b/Documentation/devicetree/bindings/input/touchscreen/zinitix,bt400.yaml
new file mode 100644
index 000000000000..b4e5ba7c0b49
--- /dev/null
+++ b/Documentation/devicetree/bindings/input/touchscreen/zinitix,bt400.yaml
@@ -0,0 +1,115 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/input/touchscreen/zinitix,bt400.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Zinitix BT4xx and BT5xx series touchscreen controller bindings
+
+description: The Zinitix BT4xx and BT5xx series of touchscreen controllers
+  are Korea-produced touchscreens with embedded microcontrollers. The
+  BT4xx series was produced 2010-2013 and the BT5xx series 2013-2014.
+
+maintainers:
+  - Michael Srba <Michael.Srba@seznam.cz>
+  - Linus Walleij <linus.walleij@linaro.org>
+
+allOf:
+  - $ref: touchscreen.yaml#
+
+properties:
+  $nodename:
+    pattern: "^touchscreen(@.*)?$"
+
+  compatible:
+    enum:
+      - zinitix,bt402
+      - zinitix,bt403
+      - zinitix,bt404
+      - zinitix,bt412
+      - zinitix,bt413
+      - zinitix,bt431
+      - zinitix,bt432
+      - zinitix,bt531
+      - zinitix,bt532
+      - zinitix,bt538
+      - zinitix,bt541
+      - zinitix,bt548
+      - zinitix,bt554
+      - zinitix,at100
+
+  reg:
+    description: I2C address on the I2C bus
+
+  clock-frequency:
+    description: I2C client clock frequency, defined for host when using
+      the device on the I2C bus
+    minimum: 0
+    maximum: 400000
+
+  interrupts:
+    description: Interrupt to host
+    maxItems: 1
+
+  vcca-supply:
+    description: Analog power supply regulator on the VCCA pin
+
+  vdd-supply:
+    description: Digital power supply regulator on the VDD pin.
+      In older device trees this can be the accidental name for the analog
+      supply on the VCCA pin, and in that case the deprecated vddo-supply is
+      used for the digital power supply.
+
+  vddo-supply:
+    description: Deprecated name for the digital power supply, use vdd-supply
+      as this reflects the real name of the pin. If this supply is present,
+      the vdd-supply represents VCCA instead of VDD. Implementers should first
+      check for this property, and if it is present assume that the vdd-supply
+      represents the analog supply.
+    deprecated: true
+
+  reset-gpios:
+    description: Reset line for the touchscreen, should be tagged
+      as GPIO_ACTIVE_LOW
+
+  zinitix,mode:
+    description: Mode of reporting touch points. Some modes may not work
+      with a particular ts firmware for unknown reasons. Available modes are
+      1 and 2. Mode 2 is the default and preferred.
+    $ref: /schemas/types.yaml#/definitions/uint32
+    enum: [1, 2]
+
+  touchscreen-size-x: true
+  touchscreen-size-y: true
+  touchscreen-fuzz-x: true
+  touchscreen-fuzz-y: true
+
+additionalProperties: false
+
+required:
+  - compatible
+  - reg
+  - interrupts
+  - touchscreen-size-x
+  - touchscreen-size-y
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/irq.h>
+    #include <dt-bindings/gpio/gpio.h>
+    i2c {
+      #address-cells = <1>;
+      #size-cells = <0>;
+
+      touchscreen@20 {
+        compatible = "zinitix,bt541";
+        reg = <0x20>;
+        interrupt-parent = <&gpio>;
+        interrupts = <13 IRQ_TYPE_EDGE_FALLING>;
+        vcca-supply = <&reg_vcca_tsp>;
+        vdd-supply = <&reg_vdd_tsp>;
+        touchscreen-size-x = <540>;
+        touchscreen-size-y = <960>;
+        zinitix,mode = <2>;
+      };
+    };
diff --git a/Documentation/devicetree/bindings/input/touchscreen/zinitix.txt b/Documentation/devicetree/bindings/input/touchscreen/zinitix.txt
deleted file mode 100644
index 446efb9f5f55..000000000000
--- a/Documentation/devicetree/bindings/input/touchscreen/zinitix.txt
+++ /dev/null
@@ -1,40 +0,0 @@
-Device tree bindings for Zinitx BT541 touchscreen controller
-
-Required properties:
-
- - compatible		: Should be "zinitix,bt541"
- - reg			: I2C address of the chip. Should be 0x20
- - interrupts		: Interrupt to which the chip is connected
-
-Optional properties:
-
- - vdd-supply		: Analog power supply regulator on VCCA pin
- - vddo-supply		: Digital power supply regulator on VDD pin
- - zinitix,mode		: Mode of reporting touch points. Some modes may not work
-			  with a particular ts firmware for unknown reasons. Available
-			  modes are 1 and 2. Mode 2 is the default and preferred.
-
-The touchscreen-* properties are documented in touchscreen.txt in this
-directory.
-
-Example:
-
-	i2c@00000000 {
-		/* ... */
-
-		bt541@20 {
-			compatible = "zinitix,bt541";
-			reg = <0x20>;
-			interrupt-parent = <&msmgpio>;
-			interrupts = <13 IRQ_TYPE_EDGE_FALLING>;
-			pinctrl-names = "default";
-			pinctrl-0 = <&tsp_default>;
-			vdd-supply = <&reg_vdd_tsp>;
-			vddo-supply = <&pm8916_l6>;
-			touchscreen-size-x = <540>;
-			touchscreen-size-y = <960>;
-			zinitix,mode = <2>;
-		};
-
-		/* ... */
-	};
-- 
2.30.2

[PATCH v3 3/6] Input: zinitix - Handle proper supply names

[Nikita Travkin]

From: Linus Walleij <linus.walleij@linaro.org>

The supply names of the Zinitix touchscreen were a bit confused, the new
bindings rectifies this.

To deal with old and new devicetrees, first check if we have "vddo" and in
case that exists assume the old supply names. Else go and look for the new
ones.

We cannot just get the regulators since we would get an OK and a dummy
regulator: we need to check explicitly for the old supply name.

Use struct device *dev as a local variable instead of the I2C client since
the device is what we are actually obtaining the resources from.

Cc: Mark Brown <broonie@kernel.org>
Cc: Michael Srba <Michael.Srba@seznam.cz>
Cc: phone-devel@vger.kernel.org
Cc: devicetree@vger.kernel.org
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
[Slightly changed the legacy regulator detection]
Signed-off-by: Nikita Travkin <nikita@trvn.ru>
---
This patch was previously submitted here:
https://lore.kernel.org/linux-input/20210625113435.2539282-2-linus.walleij@linaro.org/

Changes since the original patch:
 - Address the review comments by Dmitry:
   Drop explicit OF check and use of_find_property()
Changes in v2:
 - Reword the legacy regulator comment to drop "... and warn" as no
   warning is done. (I think adding a warning is not very useful here)
---
 drivers/input/touchscreen/zinitix.c | 21 ++++++++++++++++-----
 1 file changed, 16 insertions(+), 5 deletions(-)

diff --git a/drivers/input/touchscreen/zinitix.c b/drivers/input/touchscreen/zinitix.c
index 1e70b8d2a8d7..e84e4c3b1b3a 100644
--- a/drivers/input/touchscreen/zinitix.c
+++ b/drivers/input/touchscreen/zinitix.c
@@ -252,16 +252,27 @@ static int zinitix_init_touch(struct bt541_ts_data *bt541)
 
 static int zinitix_init_regulators(struct bt541_ts_data *bt541)
 {
-	struct i2c_client *client = bt541->client;
+	struct device *dev = &bt541->client->dev;
 	int error;
 
-	bt541->supplies[0].supply = "vdd";
-	bt541->supplies[1].supply = "vddo";
-	error = devm_regulator_bulk_get(&client->dev,
+	/*
+	 * Some older device trees have erroneous names for the regulators,
+	 * so check if "vddo" is present and in that case use these names.
+	 * Else use the proper supply names on the component.
+	 */
+	if (of_find_property(dev->of_node, "vddo-supply", NULL)) {
+		bt541->supplies[0].supply = "vdd";
+		bt541->supplies[1].supply = "vddo";
+	} else {
+		/* Else use the proper supply names */
+		bt541->supplies[0].supply = "vcca";
+		bt541->supplies[1].supply = "vdd";
+	}
+	error = devm_regulator_bulk_get(dev,
 					ARRAY_SIZE(bt541->supplies),
 					bt541->supplies);
 	if (error < 0) {
-		dev_err(&client->dev, "Failed to get regulators: %d\n", error);
+		dev_err(dev, "Failed to get regulators: %d\n", error);
 		return error;
 	}
 
-- 
2.30.2

[PATCH v3 4/6] input: zinitix: Add compatible for bt532

[Nikita Travkin]

Zinitix BT532 is another touch controller that seem to implement the
same interface as an already supported BT541. Add it to the driver.

Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Nikita Travkin <nikita@trvn.ru>
---
 drivers/input/touchscreen/zinitix.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/input/touchscreen/zinitix.c b/drivers/input/touchscreen/zinitix.c
index e84e4c3b1b3a..7c82c4f5fa6b 100644
--- a/drivers/input/touchscreen/zinitix.c
+++ b/drivers/input/touchscreen/zinitix.c
@@ -571,6 +571,7 @@ static SIMPLE_DEV_PM_OPS(zinitix_pm_ops, zinitix_suspend, zinitix_resume);
 
 #ifdef CONFIG_OF
 static const struct of_device_id zinitix_of_match[] = {
+	{ .compatible = "zinitix,bt532" },
 	{ .compatible = "zinitix,bt541" },
 	{ }
 };
-- 
2.30.2

[PATCH v3 5/6] dt-bindings: input: zinitix: Document touch-keys support

[Nikita Travkin]

In some configurations the touch controller can support the touch-keys.
Document the linux,keycodes property that enables those keys and
specifies the keycodes that should be used to report the key events.

Signed-off-by: Nikita Travkin <nikita@trvn.ru>
---
Changes in v2:
 - Include input.yaml schema at the top level instead of at the
   property. (Seems like I still can't think of the schema as device
   and not implementation-specific thing...)
 - Reword the description to be more informative.
---
 .../bindings/input/touchscreen/zinitix,bt400.yaml      | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/Documentation/devicetree/bindings/input/touchscreen/zinitix,bt400.yaml b/Documentation/devicetree/bindings/input/touchscreen/zinitix,bt400.yaml
index b4e5ba7c0b49..67ed853289b2 100644
--- a/Documentation/devicetree/bindings/input/touchscreen/zinitix,bt400.yaml
+++ b/Documentation/devicetree/bindings/input/touchscreen/zinitix,bt400.yaml
@@ -16,6 +16,7 @@ maintainers:
 
 allOf:
   - $ref: touchscreen.yaml#
+  - $ref: ../input.yaml#
 
 properties:
   $nodename:
@@ -79,6 +80,15 @@ properties:
     $ref: /schemas/types.yaml#/definitions/uint32
     enum: [1, 2]
 
+  linux,keycodes:
+    description: |
+      This property specifies an array of keycodes assigned to the
+      touch-keys that can be present in some touchscreen configurations.
+      If the touch-keys are enabled, controller firmware will assign some
+      touch sense lines to those keys.
+    minItems: 1
+    maxItems: 8
+
   touchscreen-size-x: true
   touchscreen-size-y: true
   touchscreen-fuzz-x: true
-- 
2.30.2

Re: [PATCH v3 5/6] dt-bindings: input: zinitix: Document touch-keys support

[Rob Herring]

On Thu, 06 Jan 2022 12:28:39 +0500, Nikita Travkin wrote:
> In some configurations the touch controller can support the touch-keys.
> Document the linux,keycodes property that enables those keys and
> specifies the keycodes that should be used to report the key events.
> 
> Signed-off-by: Nikita Travkin <nikita@trvn.ru>
> ---
> Changes in v2:
>  - Include input.yaml schema at the top level instead of at the
>    property. (Seems like I still can't think of the schema as device
>    and not implementation-specific thing...)
>  - Reword the description to be more informative.
> ---
>  .../bindings/input/touchscreen/zinitix,bt400.yaml      | 10 ++++++++++
>  1 file changed, 10 insertions(+)
> 

Reviewed-by: Rob Herring <robh@kernel.org>

[PATCH v3 6/6] input: zinitix: Add touchkey support

[Nikita Travkin]

Zinitix touch controllers can use some of the sense lines for virtual
keys (like those found on many phones). Add support for those keys.

Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Nikita Travkin <nikita@trvn.ru>
---
Changes in v2:
 - Add missing le16_to_cpu()
Changes in v3:
 - Add yet another missing le16_to_cpu()
---
 drivers/input/touchscreen/zinitix.c | 61 +++++++++++++++++++++++++++--
 1 file changed, 58 insertions(+), 3 deletions(-)

diff --git a/drivers/input/touchscreen/zinitix.c b/drivers/input/touchscreen/zinitix.c
index 7c82c4f5fa6b..d076dc756980 100644
--- a/drivers/input/touchscreen/zinitix.c
+++ b/drivers/input/touchscreen/zinitix.c
@@ -119,6 +119,7 @@
 
 #define DEFAULT_TOUCH_POINT_MODE		2
 #define MAX_SUPPORTED_FINGER_NUM		5
+#define MAX_SUPPORTED_BUTTON_NUM		8
 
 #define CHIP_ON_DELAY				15 // ms
 #define FIRMWARE_ON_DELAY			40 // ms
@@ -146,6 +147,8 @@ struct bt541_ts_data {
 	struct touchscreen_properties prop;
 	struct regulator_bulk_data supplies[2];
 	u32 zinitix_mode;
+	u32 keycodes[MAX_SUPPORTED_BUTTON_NUM];
+	int num_keycodes;
 };
 
 static int zinitix_read_data(struct i2c_client *client,
@@ -195,6 +198,7 @@ static int zinitix_init_touch(struct bt541_ts_data *bt541)
 	struct i2c_client *client = bt541->client;
 	int i;
 	int error;
+	u16 int_flags = 0;
 
 	error = zinitix_write_cmd(client, BT541_SWRESET_CMD);
 	if (error) {
@@ -225,6 +229,11 @@ static int zinitix_init_touch(struct bt541_ts_data *bt541)
 	if (error)
 		return error;
 
+	error = zinitix_write_u16(client, BT541_BUTTON_SUPPORTED_NUM,
+				  bt541->num_keycodes);
+	if (error)
+		return error;
+
 	error = zinitix_write_u16(client, BT541_INITIAL_TOUCH_MODE,
 				  bt541->zinitix_mode);
 	if (error)
@@ -235,9 +244,12 @@ static int zinitix_init_touch(struct bt541_ts_data *bt541)
 	if (error)
 		return error;
 
-	error = zinitix_write_u16(client, BT541_INT_ENABLE_FLAG,
-				  BIT_PT_CNT_CHANGE | BIT_DOWN | BIT_MOVE |
-					BIT_UP);
+	int_flags = BIT_PT_CNT_CHANGE | BIT_DOWN | BIT_MOVE | BIT_UP;
+
+	if (bt541->num_keycodes)
+		int_flags |= BIT_ICON_EVENT;
+
+	error = zinitix_write_u16(client, BT541_INT_ENABLE_FLAG, int_flags);
 	if (error)
 		return error;
 
@@ -329,6 +341,15 @@ static void zinitix_report_finger(struct bt541_ts_data *bt541, int slot,
 	input_report_abs(bt541->input_dev, ABS_MT_TOUCH_MAJOR, p->width);
 }
 
+static void zinitix_report_keys(struct bt541_ts_data *bt541, u16 icon_events)
+{
+	int i;
+
+	for (i = 0; i < bt541->num_keycodes; i++)
+		input_report_key(bt541->input_dev,
+				 bt541->keycodes[i], !!(icon_events & BIT(i)));
+}
+
 static irqreturn_t zinitix_ts_irq_handler(int irq, void *bt541_handler)
 {
 	struct bt541_ts_data *bt541 = bt541_handler;
@@ -336,6 +357,7 @@ static irqreturn_t zinitix_ts_irq_handler(int irq, void *bt541_handler)
 	struct touch_event touch_event;
 	int error;
 	int i;
+	__le16 icon_events = 0;
 
 	memset(&touch_event, 0, sizeof(struct touch_event));
 
@@ -346,6 +368,17 @@ static irqreturn_t zinitix_ts_irq_handler(int irq, void *bt541_handler)
 		goto out;
 	}
 
+	if (le16_to_cpu(touch_event.status) & BIT_ICON_EVENT) {
+		error = zinitix_read_data(bt541->client, BT541_ICON_STATUS_REG,
+					  &icon_events, sizeof(icon_events));
+		if (error) {
+			dev_err(&client->dev, "Failed to read icon events\n");
+			goto out;
+		}
+
+		zinitix_report_keys(bt541, le16_to_cpu(icon_events));
+	}
+
 	for (i = 0; i < MAX_SUPPORTED_FINGER_NUM; i++)
 		if (touch_event.point_coord[i].sub_status & SUB_BIT_EXIST)
 			zinitix_report_finger(bt541, i,
@@ -427,6 +460,7 @@ static int zinitix_init_input_dev(struct bt541_ts_data *bt541)
 {
 	struct input_dev *input_dev;
 	int error;
+	int i;
 
 	input_dev = devm_input_allocate_device(&bt541->client->dev);
 	if (!input_dev) {
@@ -444,6 +478,14 @@ static int zinitix_init_input_dev(struct bt541_ts_data *bt541)
 	input_dev->open = zinitix_input_open;
 	input_dev->close = zinitix_input_close;
 
+	if (bt541->num_keycodes) {
+		input_dev->keycode = bt541->keycodes;
+		input_dev->keycodemax = bt541->num_keycodes;
+		input_dev->keycodesize = sizeof(bt541->keycodes[0]);
+		for (i = 0; i < bt541->num_keycodes; i++)
+			input_set_capability(input_dev, EV_KEY, bt541->keycodes[i]);
+	}
+
 	input_set_capability(input_dev, EV_ABS, ABS_MT_POSITION_X);
 	input_set_capability(input_dev, EV_ABS, ABS_MT_POSITION_Y);
 	input_set_abs_params(input_dev, ABS_MT_WIDTH_MAJOR, 0, 255, 0, 0);
@@ -508,6 +550,19 @@ static int zinitix_ts_probe(struct i2c_client *client)
 		return error;
 	}
 
+	bt541->num_keycodes = of_property_read_variable_u32_array(
+					client->dev.of_node, "linux,keycodes",
+					bt541->keycodes, 0,
+					ARRAY_SIZE(bt541->keycodes));
+	if (bt541->num_keycodes == -EINVAL) {
+		bt541->num_keycodes = 0;
+	} else if (bt541->num_keycodes < 0) {
+		dev_err(&client->dev,
+			"Unable to parse \"linux,keycodes\" property: %d\n",
+			bt541->num_keycodes);
+		return bt541->num_keycodes;
+	}
+
 	error = zinitix_init_input_dev(bt541);
 	if (error) {
 		dev_err(&client->dev,
-- 
2.30.2