* [PATCH 2/3] dt-bindings: input: touchscreen: add Nsiway NS2009
2026-10-09 14:47 [PATCH 0/3] Add Nsiway NS2009 touchscreen support Miotsuki Mizuno
2026-10-09 14:47 ` [PATCH 1/3] dt-bindings: vendor-prefixes: add Nsiway Miotsuki Mizuno
@ 2026-10-09 14:47 ` Miotsuki Mizuno
2026-10-09 14:47 ` [PATCH 3/3] Input: add Nsiway NS2009 resistive touchscreen driver Miotsuki Mizuno
2 siblings, 0 replies; 4+ messages in thread
From: Miotsuki Mizuno @ 2026-10-09 14:47 UTC (permalink / raw)
To: Dmitry Torokhov
Cc: Rob Herring, Krzysztof Kozlowski, Conor Dooley, Icenowy Zheng,
linux-input, devicetree, linux-kernel
Describe the Nsiway NS2009 four-wire resistive touchscreen controller
and the properties used by its polling driver.
The controller returns 12-bit ADC coordinates. Use the common touchscreen
properties for coordinate ranges and orientation, and allow boards to set
the raw Z1 contact threshold through touchscreen-min-pressure. Limit that
threshold to 1..4095 because zero cannot distinguish a released contact.
Document the historical default of 80 and a board override of 150 in the
example. The Z1 threshold is for contact detection, not calibrated
pressure.
Signed-off-by: Mizuno Miotsuki <founder@crepuse.com>
---
.../input/touchscreen/nsiway,ns2009.yaml | 64 +++++++++++++++++++
MAINTAINERS | 6 ++
2 files changed, 70 insertions(+)
create mode 100644 Documentation/devicetree/bindings/input/touchscreen/nsiway,ns2009.yaml
diff --git a/Documentation/devicetree/bindings/input/touchscreen/nsiway,ns2009.yaml b/Documentation/devicetree/bindings/input/touchscreen/nsiway,ns2009.yaml
new file mode 100644
index 000000000000..04df7ba66a4a
--- /dev/null
+++ b/Documentation/devicetree/bindings/input/touchscreen/nsiway,ns2009.yaml
@@ -0,0 +1,64 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/input/touchscreen/nsiway,ns2009.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Nsiway NS2009 resistive touchscreen controller
+
+maintainers:
+ - Mizuno Miotsuki <founder@crepuse.com>
+
+description: |
+ The NS2009 is a four-wire resistive touchscreen controller connected over
+ I2C. This binding describes polling operation without a pen interrupt.
+ Coordinates are 12-bit ADC readings, not display pixel coordinates.
+
+allOf:
+ - $ref: touchscreen.yaml#
+
+properties:
+ compatible:
+ const: nsiway,ns2009
+
+ reg:
+ maxItems: 1
+
+ touchscreen-min-pressure:
+ minimum: 1
+ maximum: 4095
+ default: 80
+ description:
+ Minimum raw Z1 reading considered a touch. This is a contact detection
+ threshold, not a calibrated pressure value. Boards may require a higher
+ empirically determined threshold than the historical driver default.
+
+ touchscreen-min-x: true
+ touchscreen-min-y: true
+ touchscreen-size-x: true
+ touchscreen-size-y: true
+ touchscreen-fuzz-x: true
+ touchscreen-fuzz-y: true
+ touchscreen-inverted-x: true
+ touchscreen-inverted-y: true
+ touchscreen-swapped-x-y: true
+
+required:
+ - compatible
+ - reg
+
+additionalProperties: false
+
+examples:
+ - |
+ i2c {
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ touchscreen@48 {
+ compatible = "nsiway,ns2009";
+ reg = <0x48>;
+ touchscreen-min-pressure = <150>;
+ touchscreen-inverted-y;
+ };
+ };
diff --git a/MAINTAINERS b/MAINTAINERS
index f53047aa8d3c..696f2badc49c 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -19467,6 +19467,12 @@ S: Maintained
F: Documentation/core-api/symbol-namespaces.rst
F: scripts/nsdeps
+NSIWAY NS2009 TOUCHSCREEN CONTROLLER
+M: Mizuno Miotsuki <founder@crepuse.com>
+L: linux-input@vger.kernel.org
+S: Maintained
+F: Documentation/devicetree/bindings/input/touchscreen/nsiway,ns2009.yaml
+
NTB AMD DRIVER
M: Basavaraj Natikar <Basavaraj.Natikar@amd.com>
M: Shyam Sundar S K <Shyam-sundar.S-k@amd.com>
^ permalink raw reply [flat|nested] 4+ messages in thread* [PATCH 3/3] Input: add Nsiway NS2009 resistive touchscreen driver
2026-10-09 14:47 [PATCH 0/3] Add Nsiway NS2009 touchscreen support Miotsuki Mizuno
2026-10-09 14:47 ` [PATCH 1/3] dt-bindings: vendor-prefixes: add Nsiway Miotsuki Mizuno
2026-10-09 14:47 ` [PATCH 2/3] dt-bindings: input: touchscreen: add Nsiway NS2009 Miotsuki Mizuno
@ 2026-10-09 14:47 ` Miotsuki Mizuno
2 siblings, 0 replies; 4+ messages in thread
From: Miotsuki Mizuno @ 2026-10-09 14:47 UTC (permalink / raw)
To: Dmitry Torokhov
Cc: Rob Herring, Krzysztof Kozlowski, Conor Dooley, Icenowy Zheng,
linux-input, devicetree, linux-kernel
Add polling support for the Nsiway NS2009 I2C touchscreen controller using
the input polling API and managed input allocation. Read 12-bit X/Y ADC
values and report BTN_TOUCH from the raw Z1 contact threshold. Apply
coordinate transforms through the common touchscreen helpers.
This implementation derives from Icenowy Zheng's 2017 polling driver.
Keep its historical threshold default while allowing a firmware override,
and retain the original copyright and author attribution.
Report the touch key on every successful sample and let the input core
filter repeated values. A private pen-down flag would become stale when
the core clears key state during inhibit or reset. On a failed, short or
malformed I2C read, discard the coordinates and release the contact so a
failed bus cannot leave it stuck down. A later valid sample reports a new
contact.
Validate the zero padding in the low nibble of the second byte as specified
by the 12-bit read-command format. Reject malformed responses before
assigning the decoded value, and rate-limit the diagnostic output.
Tested on UNIHIKER M10 V1.2 with a Linux 6.18 validation module: clicks,
long presses, drags, release, axis orientation and three held-contact
inhibit/uninhibit cycles. The validation module only changes the driver
registration name to replace the existing built-in driver. Physical
NACK/short-read fault injection and system suspend/resume have not been
exercised.
Link: https://lore.kernel.org/all/20170315155140.54518-4-icenowy@aosc.xyz/
Signed-off-by: Mizuno Miotsuki <founder@crepuse.com>
---
MAINTAINERS | 1 +
drivers/input/touchscreen/Kconfig | 10 ++
drivers/input/touchscreen/Makefile | 1 +
drivers/input/touchscreen/ns2009.c | 175 +++++++++++++++++++++++++++++
4 files changed, 187 insertions(+)
create mode 100644 drivers/input/touchscreen/ns2009.c
diff --git a/MAINTAINERS b/MAINTAINERS
index 696f2badc49c..e282c02ec13f 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -19472,6 +19472,7 @@ M: Mizuno Miotsuki <founder@crepuse.com>
L: linux-input@vger.kernel.org
S: Maintained
F: Documentation/devicetree/bindings/input/touchscreen/nsiway,ns2009.yaml
+F: drivers/input/touchscreen/ns2009.c
NTB AMD DRIVER
M: Basavaraj Natikar <Basavaraj.Natikar@amd.com>
diff --git a/drivers/input/touchscreen/Kconfig b/drivers/input/touchscreen/Kconfig
index 9b9ae8ac3f7f..d4cdf1a7e057 100644
--- a/drivers/input/touchscreen/Kconfig
+++ b/drivers/input/touchscreen/Kconfig
@@ -691,6 +691,16 @@ config TOUCHSCREEN_MTOUCH
To compile this driver as a module, choose M here: the
module will be called mtouch.
+config TOUCHSCREEN_NS2009
+ tristate "Nsiway NS2009 touchscreen controller"
+ depends on I2C
+ help
+ Say Y here if you have a resistive touchscreen using the Nsiway
+ NS2009 controller connected over I2C.
+
+ To compile this driver as a module, choose M here: the module will be
+ called ns2009.
+
config TOUCHSCREEN_NOVATEK_NVT_TS
tristate "Novatek NT11205 touchscreen support"
depends on I2C
diff --git a/drivers/input/touchscreen/Makefile b/drivers/input/touchscreen/Makefile
index bfd9de83389d..c5fc2062d7cf 100644
--- a/drivers/input/touchscreen/Makefile
+++ b/drivers/input/touchscreen/Makefile
@@ -68,6 +68,7 @@ obj-$(CONFIG_TOUCHSCREEN_MIGOR) += migor_ts.o
obj-$(CONFIG_TOUCHSCREEN_MMS114) += mms114.o
obj-$(CONFIG_TOUCHSCREEN_MSG2638) += msg2638.o
obj-$(CONFIG_TOUCHSCREEN_MTOUCH) += mtouch.o
+obj-$(CONFIG_TOUCHSCREEN_NS2009) += ns2009.o
obj-$(CONFIG_TOUCHSCREEN_NOVATEK_NVT_TS) += novatek-nvt-ts.o
obj-$(CONFIG_TOUCHSCREEN_HP600) += hp680_ts_input.o
obj-$(CONFIG_TOUCHSCREEN_HP7XX) += jornada720_ts.o
diff --git a/drivers/input/touchscreen/ns2009.c b/drivers/input/touchscreen/ns2009.c
new file mode 100644
index 000000000000..d5c1f9f96bb6
--- /dev/null
+++ b/drivers/input/touchscreen/ns2009.c
@@ -0,0 +1,175 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Nsiway NS2009 resistive touchscreen controller
+ *
+ * Copyright (C) 2017 Icenowy Zheng <icenowy@aosc.xyz>
+ * Portions derived from silead.c:
+ * Copyright (C) 2014-2015 Intel Corporation
+ */
+
+#include <linux/i2c.h>
+#include <linux/input.h>
+#include <linux/input/touchscreen.h>
+#include <linux/module.h>
+#include <linux/property.h>
+
+#define NS2009_POLL_INTERVAL_MS 30
+#define NS2009_MAX_12BIT 0xfff
+
+#define NS2009_READ_X_LOW_POWER_12BIT 0xc0
+#define NS2009_READ_Y_LOW_POWER_12BIT 0xd0
+#define NS2009_READ_Z1_LOW_POWER_12BIT 0xe0
+
+/* Historical driver default; boards may override via firmware properties. */
+#define NS2009_DEFAULT_PEN_DOWN_Z1 80
+
+struct ns2009_data {
+ struct i2c_client *client;
+ struct touchscreen_properties prop;
+ u16 pen_down_z1;
+};
+
+static int ns2009_read_data(struct ns2009_data *data, u8 command, u16 *value)
+{
+ u8 raw[2];
+ int error;
+
+ error = i2c_smbus_read_i2c_block_data(data->client, command,
+ sizeof(raw), raw);
+ if (error < 0)
+ return error;
+ if (error != sizeof(raw))
+ return -EIO;
+ /* The 12-bit result is left-aligned; the remaining bits must be zero. */
+ if (raw[1] & 0x0f) {
+ dev_err_ratelimited(&data->client->dev,
+ "invalid sample for command %#02x: %02x %02x\n",
+ command, raw[0], raw[1]);
+ return -EIO;
+ }
+
+ *value = (raw[0] << 4) | (raw[1] >> 4);
+ return 0;
+}
+
+static void ns2009_poll(struct input_dev *input)
+{
+ struct ns2009_data *data = input_get_drvdata(input);
+ u16 x, y, z1;
+ int error;
+
+ error = ns2009_read_data(data, NS2009_READ_Z1_LOW_POWER_12BIT, &z1);
+ if (error)
+ goto read_error;
+
+ if (z1 < data->pen_down_z1)
+ goto release;
+
+ error = ns2009_read_data(data, NS2009_READ_X_LOW_POWER_12BIT, &x);
+ if (error)
+ goto read_error;
+
+ error = ns2009_read_data(data, NS2009_READ_Y_LOW_POWER_12BIT, &y);
+ if (error)
+ goto read_error;
+
+ /* The input core filters repeats and may independently clear key state. */
+ input_report_key(input, BTN_TOUCH, 1);
+ touchscreen_report_pos(input, &data->prop, x, y, false);
+ input_sync(input);
+ return;
+
+read_error:
+ dev_err_ratelimited(&data->client->dev,
+ "failed to poll touch data: %d\n", error);
+ /* An unreadable sample must not leave an active touch stuck down. */
+release:
+ input_report_key(input, BTN_TOUCH, 0);
+ input_sync(input);
+}
+
+static int ns2009_probe(struct i2c_client *client)
+{
+ struct device *dev = &client->dev;
+ struct ns2009_data *data;
+ struct input_dev *input;
+ u32 value;
+ int error;
+
+ if (!i2c_check_functionality(client->adapter,
+ I2C_FUNC_SMBUS_READ_I2C_BLOCK))
+ return dev_err_probe(dev, -EOPNOTSUPP,
+ "required SMBus block read is unavailable\n");
+
+ data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
+ if (!data)
+ return -ENOMEM;
+
+ input = devm_input_allocate_device(dev);
+ if (!input)
+ return -ENOMEM;
+
+ data->client = client;
+ data->pen_down_z1 = NS2009_DEFAULT_PEN_DOWN_Z1;
+ if (device_property_present(dev, "touchscreen-min-pressure")) {
+ error = device_property_read_u32(dev, "touchscreen-min-pressure",
+ &value);
+ if (error)
+ return dev_err_probe(dev, error,
+ "failed to read touchscreen-min-pressure\n");
+ if (!value || value > NS2009_MAX_12BIT)
+ return dev_err_probe(dev, -EINVAL,
+ "touchscreen-min-pressure must be 1..4095\n");
+ data->pen_down_z1 = value;
+ }
+ input_set_drvdata(input, data);
+
+ input->name = "ns2009_ts";
+ input->phys = "input/ts";
+ input->id.bustype = BUS_I2C;
+
+ __set_bit(INPUT_PROP_DIRECT, input->propbit);
+ input_set_capability(input, EV_KEY, BTN_TOUCH);
+ input_set_abs_params(input, ABS_X, 0, NS2009_MAX_12BIT, 32, 0);
+ input_set_abs_params(input, ABS_Y, 0, NS2009_MAX_12BIT, 16, 0);
+ touchscreen_parse_properties(input, false, &data->prop);
+
+ error = input_setup_polling(input, ns2009_poll);
+ if (error)
+ return dev_err_probe(dev, error, "failed to set up polling\n");
+
+ input_set_poll_interval(input, NS2009_POLL_INTERVAL_MS);
+
+ error = input_register_device(input);
+ if (error)
+ return dev_err_probe(dev, error,
+ "failed to register input device\n");
+
+ return 0;
+}
+
+static const struct i2c_device_id ns2009_id[] = {
+ { "ns2009" },
+ { }
+};
+MODULE_DEVICE_TABLE(i2c, ns2009_id);
+
+static const struct of_device_id ns2009_of_match[] = {
+ { .compatible = "nsiway,ns2009" },
+ { }
+};
+MODULE_DEVICE_TABLE(of, ns2009_of_match);
+
+static struct i2c_driver ns2009_driver = {
+ .driver = {
+ .name = "ns2009",
+ .of_match_table = ns2009_of_match,
+ },
+ .probe = ns2009_probe,
+ .id_table = ns2009_id,
+};
+module_i2c_driver(ns2009_driver);
+
+MODULE_AUTHOR("Icenowy Zheng <icenowy@aosc.xyz>");
+MODULE_DESCRIPTION("Nsiway NS2009 resistive touchscreen controller");
+MODULE_LICENSE("GPL");
^ permalink raw reply [flat|nested] 4+ messages in thread