* [PATCH v5 1/2] dt-bindings: gpio: describe Waveshare GPIO controller
2026-05-07 9:01 [PATCH v5 0/2] drm/panel: support Waveshare DSI TOUCH kits Dmitry Baryshkov
@ 2026-05-07 9:01 ` Dmitry Baryshkov
2026-05-07 9:01 ` [PATCH v5 2/2] gpio: add GPIO controller found on Waveshare DSI TOUCH panels Dmitry Baryshkov
1 sibling, 0 replies; 3+ messages in thread
From: Dmitry Baryshkov @ 2026-05-07 9:01 UTC (permalink / raw)
To: Neil Armstrong, Jessica Zhang, David Airlie, Simona Vetter,
Maarten Lankhorst, Maxime Ripard, Thomas Zimmermann, Rob Herring,
Krzysztof Kozlowski, Conor Dooley, Cong Yang, Ondrej Jirman,
Javier Martinez Canillas, Jagan Teki, Liam Girdwood, Mark Brown,
Linus Walleij, Bartosz Golaszewski, Jie Gan
Cc: dri-devel, devicetree, linux-kernel, linux-gpio, Conor Dooley
The Waveshare DSI TOUCH family of panels has separate on-board GPIO
controller, which controls power supplies to the panel and the touch
screen and provides reset pins for both the panel and the touchscreen.
Also it provides a simple PWM controller for panel backlight.
Add bindings for these GPIO controllers. As overall integration might be
not very obvious (and it differs significantly from the bindings used by
the original drivers), provide complete example with the on-board
regulators and the DSI panel.
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
---
.../bindings/gpio/waveshare,dsi-touch-gpio.yaml | 73 ++++++++++++++++++++++
1 file changed, 73 insertions(+)
diff --git a/Documentation/devicetree/bindings/gpio/waveshare,dsi-touch-gpio.yaml b/Documentation/devicetree/bindings/gpio/waveshare,dsi-touch-gpio.yaml
new file mode 100644
index 000000000000..091e1fffcd47
--- /dev/null
+++ b/Documentation/devicetree/bindings/gpio/waveshare,dsi-touch-gpio.yaml
@@ -0,0 +1,73 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/gpio/waveshare,dsi-touch-gpio.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Waveshare GPIO controller on DSI TOUCH panels
+
+maintainers:
+ - Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
+
+description:
+ Waveshare DSI TOUCH panel kits contain separate GPIO controller for toggling
+ power supplies and panel / touchscreen resets.
+
+properties:
+ compatible:
+ const: waveshare,dsi-touch-gpio
+
+ reg:
+ maxItems: 1
+
+ gpio-controller: true
+
+ '#gpio-cells':
+ const: 2
+
+required:
+ - compatible
+ - reg
+ - gpio-controller
+ - "#gpio-cells"
+
+additionalProperties: false
+
+examples:
+ - |
+ #include <dt-bindings/gpio/gpio.h>
+
+ i2c {
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ wsgpio: gpio@45 {
+ compatible = "waveshare,dsi-touch-gpio";
+ reg = <0x45>;
+ gpio-controller;
+ #gpio-cells = <2>;
+ };
+ };
+
+ panel_avdd: regulator-panel-avdd {
+ compatible = "regulator-fixed";
+ regulator-name = "panel-avdd";
+ gpios = <&wsgpio 0 GPIO_ACTIVE_HIGH>;
+ enable-active-high;
+ };
+
+ panel_iovcc: regulator-panel-iovcc {
+ compatible = "regulator-fixed";
+ regulator-name = "panel-iovcc";
+ gpios = <&wsgpio 4 GPIO_ACTIVE_HIGH>;
+ enable-active-high;
+ };
+
+ panel_vcc: regulator-panel-vcc {
+ compatible = "regulator-fixed";
+ regulator-name = "panel-vcc";
+ gpios = <&wsgpio 8 GPIO_ACTIVE_HIGH>;
+ enable-active-high;
+ regulator-always-on;
+ };
+...
--
2.47.3
^ permalink raw reply related [flat|nested] 3+ messages in thread* [PATCH v5 2/2] gpio: add GPIO controller found on Waveshare DSI TOUCH panels
2026-05-07 9:01 [PATCH v5 0/2] drm/panel: support Waveshare DSI TOUCH kits Dmitry Baryshkov
2026-05-07 9:01 ` [PATCH v5 1/2] dt-bindings: gpio: describe Waveshare GPIO controller Dmitry Baryshkov
@ 2026-05-07 9:01 ` Dmitry Baryshkov
1 sibling, 0 replies; 3+ messages in thread
From: Dmitry Baryshkov @ 2026-05-07 9:01 UTC (permalink / raw)
To: Neil Armstrong, Jessica Zhang, David Airlie, Simona Vetter,
Maarten Lankhorst, Maxime Ripard, Thomas Zimmermann, Rob Herring,
Krzysztof Kozlowski, Conor Dooley, Cong Yang, Ondrej Jirman,
Javier Martinez Canillas, Jagan Teki, Liam Girdwood, Mark Brown,
Linus Walleij, Bartosz Golaszewski, Jie Gan
Cc: dri-devel, devicetree, linux-kernel, linux-gpio, Riccardo Mereu
The Waveshare DSI TOUCH family of panels has separate on-board GPIO
controller, which controls power supplies to the panel and the touch
screen and provides reset pins for both the panel and the touchscreen.
Also it provides a simple PWM controller for panel backlight. Add
support for this GPIO controller.
Tested-by: Riccardo Mereu <r.mereu@arduino.cc>
Reviewed-by: Linus Walleij <linusw@kernel.org>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
---
drivers/gpio/Kconfig | 10 ++
drivers/gpio/Makefile | 1 +
drivers/gpio/gpio-waveshare-dsi.c | 208 ++++++++++++++++++++++++++++++++++++++
3 files changed, 219 insertions(+)
diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index ce95a25298a8..8ae6a423da6d 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -806,6 +806,16 @@ config GPIO_VISCONTI
help
Say yes here to support GPIO on Tohisba Visconti.
+config GPIO_WAVESHARE_DSI_TOUCH
+ tristate "Waveshare GPIO controller for DSI panels"
+ depends on BACKLIGHT_CLASS_DEVICE
+ depends on I2C
+ select REGMAP_I2C
+ help
+ Enable support for the GPIO and PWM controller found on Waveshare DSI
+ TOUCH panel kits. It provides GPIOs (used for regulator control and
+ resets) and backlight support.
+
config GPIO_WCD934X
tristate "Qualcomm WCD9340/WCD9341 GPIO controller driver"
depends on MFD_WCD934X
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index b267598b517d..2ea47d9d3dca 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -205,6 +205,7 @@ obj-$(CONFIG_GPIO_VIRTUSER) += gpio-virtuser.o
obj-$(CONFIG_GPIO_VIRTIO) += gpio-virtio.o
obj-$(CONFIG_GPIO_VISCONTI) += gpio-visconti.o
obj-$(CONFIG_GPIO_VX855) += gpio-vx855.o
+obj-$(CONFIG_GPIO_WAVESHARE_DSI_TOUCH) += gpio-waveshare-dsi.o
obj-$(CONFIG_GPIO_WCD934X) += gpio-wcd934x.o
obj-$(CONFIG_GPIO_WHISKEY_COVE) += gpio-wcove.o
obj-$(CONFIG_GPIO_WINBOND) += gpio-winbond.o
diff --git a/drivers/gpio/gpio-waveshare-dsi.c b/drivers/gpio/gpio-waveshare-dsi.c
new file mode 100644
index 000000000000..38f52351bb58
--- /dev/null
+++ b/drivers/gpio/gpio-waveshare-dsi.c
@@ -0,0 +1,208 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2024 Waveshare International Limited
+ * Copyright (c) Qualcomm Technologies, Inc. and/or its subsidiaries.
+ */
+
+#include <linux/backlight.h>
+#include <linux/err.h>
+#include <linux/fb.h>
+#include <linux/gpio/driver.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/regmap.h>
+
+/* I2C registers of the microcontroller. */
+#define REG_TP 0x94
+#define REG_LCD 0x95
+#define REG_PWM 0x96
+#define REG_SIZE 0x97
+#define REG_ID 0x98
+#define REG_VERSION 0x99
+
+enum {
+ GPIO_AVDD = 0,
+ GPIO_PANEL_RESET = 1,
+ GPIO_BL_ENABLE = 2,
+ GPIO_IOVCC = 4,
+ GPIO_VCC = 8,
+ GPIO_TS_RESET = 9,
+};
+
+#define NUM_GPIO 16
+
+struct waveshare_gpio {
+ struct mutex dir_lock;
+ struct mutex pwr_lock;
+ struct regmap *regmap;
+ u16 poweron_state;
+
+ struct gpio_chip gc;
+};
+
+static const struct regmap_config waveshare_gpio_regmap_config = {
+ .reg_bits = 8,
+ .val_bits = 8,
+ .max_register = REG_VERSION,
+};
+
+static int waveshare_gpio_get(struct waveshare_gpio *state, unsigned int offset)
+{
+ u16 pwr_state;
+
+ guard(mutex)(&state->pwr_lock);
+ pwr_state = state->poweron_state & BIT(offset);
+
+ return !!pwr_state;
+}
+
+static int waveshare_gpio_set(struct waveshare_gpio *state, unsigned int offset, int value)
+{
+ u16 last_val;
+ int err;
+
+ guard(mutex)(&state->pwr_lock);
+
+ last_val = state->poweron_state;
+ if (value)
+ last_val |= BIT(offset);
+ else
+ last_val &= ~BIT(offset);
+
+ state->poweron_state = last_val;
+
+ err = regmap_write(state->regmap, REG_TP, last_val >> 8);
+ if (!err)
+ err = regmap_write(state->regmap, REG_LCD, last_val & 0xff);
+
+ return err;
+}
+
+static int waveshare_gpio_gpio_get_direction(struct gpio_chip *gc, unsigned int offset)
+{
+ return GPIO_LINE_DIRECTION_OUT;
+}
+
+static int waveshare_gpio_gpio_get(struct gpio_chip *gc, unsigned int offset)
+{
+ struct waveshare_gpio *state = gpiochip_get_data(gc);
+
+ return waveshare_gpio_get(state, offset);
+}
+
+static int waveshare_gpio_gpio_set(struct gpio_chip *gc, unsigned int offset, int value)
+{
+ struct waveshare_gpio *state = gpiochip_get_data(gc);
+
+ return waveshare_gpio_set(state, offset, value);
+}
+
+static int waveshare_gpio_update_status(struct backlight_device *bl)
+{
+ struct waveshare_gpio *state = bl_get_data(bl);
+ int brightness = backlight_get_brightness(bl);
+
+ waveshare_gpio_set(state, GPIO_BL_ENABLE, brightness);
+
+ return regmap_write(state->regmap, REG_PWM, brightness);
+}
+
+static const struct backlight_ops waveshare_gpio_bl = {
+ .update_status = waveshare_gpio_update_status,
+};
+
+static int waveshare_gpio_probe(struct i2c_client *i2c)
+{
+ struct backlight_properties props = {};
+ struct waveshare_gpio *state;
+ struct device *dev = &i2c->dev;
+ struct backlight_device *bl;
+ struct regmap *regmap;
+ unsigned int data;
+ int ret;
+
+ state = devm_kzalloc(dev, sizeof(*state), GFP_KERNEL);
+ if (!state)
+ return -ENOMEM;
+
+ ret = devm_mutex_init(dev, &state->dir_lock);
+ if (ret)
+ return ret;
+
+ ret = devm_mutex_init(dev, &state->pwr_lock);
+ if (ret)
+ return ret;
+
+ regmap = devm_regmap_init_i2c(i2c, &waveshare_gpio_regmap_config);
+ if (IS_ERR(regmap))
+ return dev_err_probe(dev, PTR_ERR(regmap), "Failed to allocate register map\n");
+
+ state->regmap = regmap;
+ i2c_set_clientdata(i2c, state);
+
+ ret = regmap_read(regmap, REG_ID, &data);
+ if (ret < 0)
+ return dev_err_probe(dev, ret, "Failed to read register\n");
+
+ dev_dbg(dev, "waveshare panel hw id = 0x%x\n", data);
+
+ ret = regmap_read(regmap, REG_SIZE, &data);
+ if (ret < 0)
+ return dev_err_probe(dev, ret, "Failed to read register\n");
+
+ dev_dbg(dev, "waveshare panel size = %d\n", data);
+
+ ret = regmap_read(regmap, REG_VERSION, &data);
+ if (ret < 0)
+ return dev_err_probe(dev, ret, "Failed to read register\n");
+
+ dev_dbg(dev, "waveshare panel mcu version = 0x%x\n", data);
+
+ ret = waveshare_gpio_set(state, GPIO_TS_RESET, 1);
+ if (ret)
+ return dev_err_probe(dev, ret, "Failed to program GPIOs\n");
+
+ msleep(20);
+
+ state->gc.parent = dev;
+ state->gc.label = i2c->name;
+ state->gc.owner = THIS_MODULE;
+ state->gc.base = -1;
+ state->gc.ngpio = NUM_GPIO;
+
+ /* it is output only */
+ state->gc.get = waveshare_gpio_gpio_get;
+ state->gc.set = waveshare_gpio_gpio_set;
+ state->gc.get_direction = waveshare_gpio_gpio_get_direction;
+ state->gc.can_sleep = true;
+
+ ret = devm_gpiochip_add_data(dev, &state->gc, state);
+ if (ret)
+ return dev_err_probe(dev, ret, "Failed to create gpiochip\n");
+
+ props.type = BACKLIGHT_RAW;
+ props.max_brightness = 255;
+ props.brightness = 255;
+ bl = devm_backlight_device_register(dev, dev_name(dev), dev, state,
+ &waveshare_gpio_bl, &props);
+ return PTR_ERR_OR_ZERO(bl);
+}
+
+static const struct of_device_id waveshare_gpio_dt_ids[] = {
+ { .compatible = "waveshare,dsi-touch-gpio" },
+ {},
+};
+MODULE_DEVICE_TABLE(of, waveshare_gpio_dt_ids);
+
+static struct i2c_driver waveshare_gpio_regulator_driver = {
+ .driver = {
+ .name = "waveshare-regulator",
+ .of_match_table = of_match_ptr(waveshare_gpio_dt_ids),
+ },
+ .probe = waveshare_gpio_probe,
+};
+
+module_i2c_driver(waveshare_gpio_regulator_driver);
+
+MODULE_DESCRIPTION("GPIO controller driver for Waveshare DSI touch panels");
+MODULE_LICENSE("GPL");
--
2.47.3
^ permalink raw reply related [flat|nested] 3+ messages in thread