[PATCH v1 0/2] Add tc3408 bindings and timing

[PATCH v1 0/2] Add tc3408 bindings and timing

[Langyan Ye]

The tc3408 touch screen chip same as Elan eKTH6915 controller
has a reset gpio. The difference is that they have different
post_power_delay_ms.

According to the Parade TC3408 datasheet, the reset pin requires a
pull-down duration longer than 10 ms, therefore post_power_delay_ms
is set to 10. In addition, the chipset requires an initialization
time greater than 300 ms after reset, so post_gpio_reset_on_delay_ms
is configured as 300.

Langyan Ye (2):
  dt-bindings: HID: i2c-hid: parade: Introduce bindings for Parade
    tc3408
  HID: i2c-hid: elan: Add parade-tc3408 timing

 .../bindings/input/parade,tc3408.yaml         | 72 +++++++++++++++++++
 drivers/hid/i2c-hid/i2c-hid-of-elan.c         |  8 +++
 2 files changed, 80 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/input/parade,tc3408.yaml

-- 
2.34.1

[PATCH v1 1/2] dt-bindings: HID: i2c-hid: parade: Introduce bindings for Parade tc3408

[Langyan Ye]

The tc3408 touch screen chip same as Elan eKTH6915 controller
has a reset gpio. The difference is that they have different
post_power_delay_ms.

Signed-off-by: Langyan Ye <yelangyan@huaqin.corp-partner.google.com>
---
 .../bindings/input/parade,tc3408.yaml         | 72 +++++++++++++++++++
 1 file changed, 72 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/input/parade,tc3408.yaml

diff --git a/Documentation/devicetree/bindings/input/parade,tc3408.yaml b/Documentation/devicetree/bindings/input/parade,tc3408.yaml
new file mode 100644
index 000000000000..25db85e90b18
--- /dev/null
+++ b/Documentation/devicetree/bindings/input/parade,tc3408.yaml
@@ -0,0 +1,72 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/input/parade,tc3408.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Parade tc3408 touchscreen controller
+
+maintainers:
+  - Langyan Ye <yelangyan@huaqin.corp-partner.google.com>
+
+description:
+  Supports the Parade tc3408 touchscreen controller.
+  This touchscreen controller uses the i2c-hid protocol with a reset GPIO.
+
+allOf:
+  - $ref: /schemas/input/touchscreen/touchscreen.yaml#
+
+properties:
+  compatible:
+    const: parade,tc3408
+
+  reg:
+    const: 0x24
+
+  interrupts:
+    maxItems: 1
+
+  panel: true
+
+  reset-gpios:
+    maxItems: 1
+    description: Reset GPIO.
+
+  vcc33-supply:
+    description: The 3.3V supply to the touchscreen.
+
+  vccio-supply:
+    description: The 1.8V supply to the touchscreen.
+
+required:
+  - compatible
+  - reg
+  - interrupts
+  - panel
+  - vcc33-supply
+  - vccio-supply
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/gpio/gpio.h>
+    #include <dt-bindings/interrupt-controller/irq.h>
+
+    i2c {
+      #address-cells = <1>;
+      #size-cells = <0>;
+
+      touchscreen: touchscreen@24 {
+        compatible = "parade,tc3408";
+        reg = <0x24>;
+
+        interrupt-parent = <&pio>;
+        interrupts = <15 IRQ_TYPE_LEVEL_LOW>;
+
+        panel = <&panel>;
+        reset-gpios = <&pio 126 GPIO_ACTIVE_LOW>;
+        vcc33-supply = <&pp3300_tchscr_x>;
+        vccio-supply = <&pp1800_tchscr_report_disable>;
+      };
+    };
-- 
2.34.1

[PATCH v1 2/2] HID: i2c-hid: elan: Add parade-tc3408 timing

[Langyan Ye]

Parade-tc3408 requires reset to pull down time greater than 10ms,
so the configuration post_power_delay_ms is 10, and the chipset
initial time is required to be greater than 300ms,
so the post_gpio_reset_on_delay_ms is set to 300.

Signed-off-by: Langyan Ye <yelangyan@huaqin.corp-partner.google.com>
---
 drivers/hid/i2c-hid/i2c-hid-of-elan.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/hid/i2c-hid/i2c-hid-of-elan.c b/drivers/hid/i2c-hid/i2c-hid-of-elan.c
index 3fcff6daa0d3..23826cb808b7 100644
--- a/drivers/hid/i2c-hid/i2c-hid-of-elan.c
+++ b/drivers/hid/i2c-hid/i2c-hid-of-elan.c
@@ -179,11 +179,19 @@ static const struct elan_i2c_hid_chip_data ilitek_ili2901_chip_data = {
 	.main_supply_name = "vcc33",
 };
 
+static const struct elan_i2c_hid_chip_data parade_tc3408_chip_data = {
+       .post_power_delay_ms = 10,
+       .post_gpio_reset_on_delay_ms = 100,
+       .hid_descriptor_address = 0x0001,
+       .main_supply_name = "vcc33",
+};
+
 static const struct of_device_id elan_i2c_hid_of_match[] = {
 	{ .compatible = "elan,ekth6915", .data = &elan_ekth6915_chip_data },
 	{ .compatible = "elan,ekth6a12nay", .data = &elan_ekth6a12nay_chip_data },
 	{ .compatible = "ilitek,ili9882t", .data = &ilitek_ili9882t_chip_data },
 	{ .compatible = "ilitek,ili2901", .data = &ilitek_ili2901_chip_data },
+	{ .compatible = "parade,tc3408", .data = &parade_tc3408_chip_data },
 	{ }
 };
 MODULE_DEVICE_TABLE(of, elan_i2c_hid_of_match);
-- 
2.34.1

Re: [PATCH v1 1/2] dt-bindings: HID: i2c-hid: parade: Introduce bindings for Parade tc3408

[Rob Herring (Arm)]

On Tue, 19 Aug 2025 11:48:51 +0800, Langyan Ye wrote:
> The tc3408 touch screen chip same as Elan eKTH6915 controller
> has a reset gpio. The difference is that they have different
> post_power_delay_ms.
> 
> Signed-off-by: Langyan Ye <yelangyan@huaqin.corp-partner.google.com>
> ---
>  .../bindings/input/parade,tc3408.yaml         | 72 +++++++++++++++++++
>  1 file changed, 72 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/input/parade,tc3408.yaml
> 

My bot found errors running 'make dt_binding_check' on your patch:

yamllint warnings/errors:

dtschema/dtc warnings/errors:


doc reference errors (make refcheckdocs):

See https://patchwork.ozlabs.org/project/devicetree-bindings/patch/20250819034852.1230264-2-yelangyan@huaqin.corp-partner.google.com

The base for the series is generally the latest rc1. A different dependency
should be noted in *this* patch.

If you already ran 'make dt_binding_check' and didn't see the above
error(s), then make sure 'yamllint' is installed and dt-schema is up to
date:

pip3 install dtschema --upgrade

Please check and re-submit after running the above command yourself. Note
that DT_SCHEMA_FILES can be set to your schema file to speed up checking
your schema. However, it must be unset to test all examples with your schema.

Re: [PATCH v1 1/2] dt-bindings: HID: i2c-hid: parade: Introduce bindings for Parade tc3408

[Krzysztof Kozlowski]

On Tue, Aug 19, 2025 at 11:48:51AM +0800, Langyan Ye wrote:
> The tc3408 touch screen chip same as Elan eKTH6915 controller
> has a reset gpio. The difference is that they have different
> post_power_delay_ms.
> 
> Signed-off-by: Langyan Ye <yelangyan@huaqin.corp-partner.google.com>

A nit, subject: drop second/last, redundant "bindings for". The
"dt-bindings" prefix is already stating that these are bindings.
See also:
https://elixir.bootlin.com/linux/v6.7-rc8/source/Documentation/devicetree/bindings/submitting-patches.rst#L18

Just "Add foo bar"


> ---
>  .../bindings/input/parade,tc3408.yaml         | 72 +++++++++++++++++++
>  1 file changed, 72 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/input/parade,tc3408.yaml
> 
> diff --git a/Documentation/devicetree/bindings/input/parade,tc3408.yaml b/Documentation/devicetree/bindings/input/parade,tc3408.yaml
> new file mode 100644
> index 000000000000..25db85e90b18
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/input/parade,tc3408.yaml
> @@ -0,0 +1,72 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/input/parade,tc3408.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Parade tc3408 touchscreen controller
> +
> +maintainers:
> +  - Langyan Ye <yelangyan@huaqin.corp-partner.google.com>
> +
> +description:
> +  Supports the Parade tc3408 touchscreen controller.

Describe the hardware, not what binding supports. You just repeated
title, BTW.

> +  This touchscreen controller uses the i2c-hid protocol with a reset GPIO.
> +
> +allOf:
> +  - $ref: /schemas/input/touchscreen/touchscreen.yaml#
> +
> +properties:
> +  compatible:
> +    const: parade,tc3408
> +
> +  reg:
> +    const: 0x24
> +
> +  interrupts:
> +    maxItems: 1
> +
> +  panel: true

Drop

> +
> +  reset-gpios:
> +    maxItems: 1
> +    description: Reset GPIO.

Drop description, redundant.

> +
> +  vcc33-supply:
> +    description: The 3.3V supply to the touchscreen.
> +
> +  vccio-supply:
> +    description: The 1.8V supply to the touchscreen.
> +
> +required:
> +  - compatible
> +  - reg
> +  - interrupts
> +  - panel
> +  - vcc33-supply
> +  - vccio-supply
> +
> +additionalProperties: false

unevaluatedProperties instead

Best regards,
Krzysztof