[PATCH 0/3] Add Himax HX83112A support for Fairphone 4 touchscreen

[PATCH 0/3] Add Himax HX83112A support for Fairphone 4 touchscreen

[Luca Weiss]

Add bindings, driver modifications and dts additions to support the
touchscreen on the Fairphone 4.

Signed-off-by: Luca Weiss <luca.weiss@fairphone.com>
---
Luca Weiss (3):
      dt-bindings: touchscreen: trivial-touch: Add Himax HX83112A
      Input: himax_hx83112b - Add HX83112A support
      arm64: dts: qcom: sm7225-fairphone-fp4: Enable touchscreen

 .../bindings/input/touchscreen/trivial-touch.yaml  |  2 +
 arch/arm64/boot/dts/qcom/sm7225-fairphone-fp4.dts  | 21 +++++++++-
 drivers/input/touchscreen/himax_hx83112b.c         | 46 ++++++++++++++++++++++
 3 files changed, 68 insertions(+), 1 deletion(-)
---
base-commit: 237a1c39e8dfd3e1c6f1f023eea37a48ec04cc63
change-id: 20260820-fp4-hx83112a-b3e14819ae14

Best regards,
--  
Luca Weiss <luca.weiss@fairphone.com>

[PATCH 1/3] dt-bindings: touchscreen: trivial-touch: Add Himax HX83112A

[Luca Weiss]

Describe the compatible for the Himax HX83112A touchscreen controller,
which doesn't need any special resources not described in the
trivial-touch bindings.

Signed-off-by: Luca Weiss <luca.weiss@fairphone.com>
---
 Documentation/devicetree/bindings/input/touchscreen/trivial-touch.yaml | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/Documentation/devicetree/bindings/input/touchscreen/trivial-touch.yaml b/Documentation/devicetree/bindings/input/touchscreen/trivial-touch.yaml
index 6316a8d32f39..a4b535bdbd6c 100644
--- a/Documentation/devicetree/bindings/input/touchscreen/trivial-touch.yaml
+++ b/Documentation/devicetree/bindings/input/touchscreen/trivial-touch.yaml
@@ -18,6 +18,8 @@ properties:
       - azoteq,iqs525
       # Himax hx83100a touchscreen controller
       - himax,hx83100a
+      # Himax hx83112a touchscreen controller
+      - himax,hx83112a
       # Himax hx83112b touchscreen controller
       - himax,hx83112b
       # Hynitron cstxxx series touchscreen controller

-- 
2.55.0

[PATCH 2/3] Input: himax_hx83112b - Add HX83112A support

[Luca Weiss]

The HX83112A touch controller works nearly identical to other supported
chips, we just need a small dance before we can start using the
touchscreen.

For that a new 'init' callback is introduced to facilitate that.

Assisted-by: Gemini:gemini-3.1-pro
Signed-off-by: Luca Weiss <luca.weiss@fairphone.com>
---
 drivers/input/touchscreen/himax_hx83112b.c | 46 ++++++++++++++++++++++++++++++
 1 file changed, 46 insertions(+)

diff --git a/drivers/input/touchscreen/himax_hx83112b.c b/drivers/input/touchscreen/himax_hx83112b.c
index 0aa67dfacbad..cc8b904d88e6 100644
--- a/drivers/input/touchscreen/himax_hx83112b.c
+++ b/drivers/input/touchscreen/himax_hx83112b.c
@@ -62,6 +62,7 @@ struct himax_ts_data;
 struct himax_chip {
 	u32 id;
 	int (*check_id)(struct himax_ts_data *ts);
+	int (*init)(struct himax_ts_data *ts);
 	int (*read_events)(struct himax_ts_data *ts, struct himax_event *event,
 			   size_t length);
 };
@@ -364,6 +365,12 @@ static int himax_probe(struct i2c_client *client)
 			return error;
 	}
 
+	if (ts->chip->init) {
+		error = ts->chip->init(ts);
+		if (error)
+			return error;
+	}
+
 	error = himax_input_register(ts);
 	if (error)
 		return error;
@@ -395,10 +402,47 @@ static int himax_resume(struct device *dev)
 
 static DEFINE_SIMPLE_DEV_PM_OPS(himax_pm_ops, himax_suspend, himax_resume);
 
+static int hx83112a_init(struct himax_ts_data *ts)
+{
+	int error;
+	u32 buf[2];
+
+	/*
+	 * By default, the chip boots into safe mode. We clear the FW ISR
+	 * register and perform a second hardware reset to boot normally.
+	 */
+	buf[0] = 0x9000005c;
+	buf[1] = 0x00000000;
+	error = regmap_bulk_write(ts->regmap, HIMAX_AHB_ADDR_BYTE_0, buf, 2);
+	if (error)
+		return error;
+
+	himax_reset(ts);
+
+	/* Give the MCU time to reload firmware */
+	msleep(100);
+
+	/* Enable the touch algorithm */
+	buf[0] = 0x1000748c;
+	buf[1] = 0xa55aa55a;
+	error = regmap_bulk_write(ts->regmap, HIMAX_AHB_ADDR_BYTE_0, buf, 2);
+	if (error)
+		return error;
+
+	return 0;
+}
+
 static const struct himax_chip hx83100a_chip = {
 	.read_events = hx83100a_read_events,
 };
 
+static const struct himax_chip hx83112a_chip = {
+	.id = 0x83112a,
+	.check_id = himax_check_product_id,
+	.init = hx83112a_init,
+	.read_events = himax_read_events,
+};
+
 static const struct himax_chip hx83112b_chip = {
 	.id = 0x83112b,
 	.check_id = himax_check_product_id,
@@ -407,6 +451,7 @@ static const struct himax_chip hx83112b_chip = {
 
 static const struct i2c_device_id himax_ts_id[] = {
 	{ .name = "hx83100a", .driver_data = (kernel_ulong_t)&hx83100a_chip },
+	{ .name = "hx83112a", .driver_data = (kernel_ulong_t)&hx83112a_chip },
 	{ .name = "hx83112b", .driver_data = (kernel_ulong_t)&hx83112b_chip },
 	{ /* sentinel */ }
 };
@@ -415,6 +460,7 @@ MODULE_DEVICE_TABLE(i2c, himax_ts_id);
 #ifdef CONFIG_OF
 static const struct of_device_id himax_of_match[] = {
 	{ .compatible = "himax,hx83100a", .data = &hx83100a_chip },
+	{ .compatible = "himax,hx83112a", .data = &hx83112a_chip },
 	{ .compatible = "himax,hx83112b", .data = &hx83112b_chip },
 	{ /* sentinel */ }
 };

-- 
2.55.0

[PATCH 3/3] arm64: dts: qcom: sm7225-fairphone-fp4: Enable touchscreen

[Luca Weiss]

Add a node and pinctrl for the Himax HX83112A touchscreen found on this
phone.

Signed-off-by: Luca Weiss <luca.weiss@fairphone.com>
---
 arch/arm64/boot/dts/qcom/sm7225-fairphone-fp4.dts | 21 ++++++++++++++++++++-
 1 file changed, 20 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/boot/dts/qcom/sm7225-fairphone-fp4.dts b/arch/arm64/boot/dts/qcom/sm7225-fairphone-fp4.dts
index 23f950067a08..ff609f7e1796 100644
--- a/arch/arm64/boot/dts/qcom/sm7225-fairphone-fp4.dts
+++ b/arch/arm64/boot/dts/qcom/sm7225-fairphone-fp4.dts
@@ -626,7 +626,19 @@ &i2c8 {
 	clock-frequency = <400000>;
 	status = "okay";
 
-	/* HX83112A touchscreen @ 48 */
+	touchscreen@48 {
+		compatible = "himax,hx83112a";
+		reg = <0x48>;
+
+		interrupts-extended = <&tlmm 22 IRQ_TYPE_EDGE_FALLING>;
+		reset-gpios = <&tlmm 21 GPIO_ACTIVE_LOW>;
+
+		touchscreen-size-x = <1080>;
+		touchscreen-size-y = <2340>;
+
+		pinctrl-0 = <&touchscreen_default>;
+		pinctrl-names = "default";
+	};
 };
 
 &i2c10 {
@@ -1117,6 +1129,13 @@ platform {
 &tlmm {
 	gpio-reserved-ranges = <13 4>, <56 2>;
 
+	touchscreen_default: touchscreen-default-state {
+		pins = "gpio21", "gpio22";
+		function = "gpio";
+		drive-strength = <8>;
+		bias-pull-up;
+	};
+
 	qup_uart1_sleep_cts: qup-uart1-sleep-cts-state {
 		pins = "gpio61";
 		function = "gpio";

-- 
2.55.0

Re: [PATCH 3/3] arm64: dts: qcom: sm7225-fairphone-fp4: Enable touchscreen

[Abel Vesa]

On 26-08-21 09:12:20, Luca Weiss wrote:
> Add a node and pinctrl for the Himax HX83112A touchscreen found on this
> phone.
> 
> Signed-off-by: Luca Weiss <luca.weiss@fairphone.com>

Reviewed-by: Abel Vesa <abel.vesa@oss.qualcomm.com>

Re: [PATCH 3/3] arm64: dts: qcom: sm7225-fairphone-fp4: Enable touchscreen

[David Heidelberg]

On 21/08/2026 09:12, Luca Weiss wrote:
> Add a node and pinctrl for the Himax HX83112A touchscreen found on this
> phone.
> 
> Signed-off-by: Luca Weiss <luca.weiss@fairphone.com>
> ---
>   arch/arm64/boot/dts/qcom/sm7225-fairphone-fp4.dts | 21 ++++++++++++++++++++-
>   1 file changed, 20 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/arm64/boot/dts/qcom/sm7225-fairphone-fp4.dts b/arch/arm64/boot/dts/qcom/sm7225-fairphone-fp4.dts
> index 23f950067a08..ff609f7e1796 100644
> --- a/arch/arm64/boot/dts/qcom/sm7225-fairphone-fp4.dts
> +++ b/arch/arm64/boot/dts/qcom/sm7225-fairphone-fp4.dts
> @@ -626,7 +626,19 @@ &i2c8 {
>   	clock-frequency = <400000>;
>   	status = "okay";
>   
> -	/* HX83112A touchscreen @ 48 */
> +	touchscreen@48 {
> +		compatible = "himax,hx83112a";
> +		reg = <0x48>;
> +
> +		interrupts-extended = <&tlmm 22 IRQ_TYPE_EDGE_FALLING>;
> +		reset-gpios = <&tlmm 21 GPIO_ACTIVE_LOW>;
> +
> +		touchscreen-size-x = <1080>;
> +		touchscreen-size-y = <2340>;
> +
> +		pinctrl-0 = <&touchscreen_default>;
> +		pinctrl-names = "default";
> +	};
>   };
>   
>   &i2c10 {
> @@ -1117,6 +1129,13 @@ platform {
>   &tlmm {
>   	gpio-reserved-ranges = <13 4>, <56 2>;
>   
> +	touchscreen_default: touchscreen-default-state {
> +		pins = "gpio21", "gpio22";

I guess you could use here irq-pins {}, reset-pins {},

but with or without change,

Reviewed-by: David Heidelberg <david@ixit.cz>

> +		function = "gpio";
> +		drive-strength = <8>;
> +		bias-pull-up;
> +	};
> +
>   	qup_uart1_sleep_cts: qup-uart1-sleep-cts-state {
>   		pins = "gpio61";
>   		function = "gpio";
> 

Re: [PATCH 3/3] arm64: dts: qcom: sm7225-fairphone-fp4: Enable touchscreen

[Konrad Dybcio]

On 8/21/26 9:12 AM, Luca Weiss wrote:
> Add a node and pinctrl for the Himax HX83112A touchscreen found on this
> phone.
> 
> Signed-off-by: Luca Weiss <luca.weiss@fairphone.com>
> ---

Reviewed-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>

Konrad