From: Dmitry Baryshkov Date: Thu, 7 May 2026 09:01:33 +0000 (+0300) Subject: gpio: add GPIO controller found on Waveshare DSI TOUCH panels X-Git-Url: http://git.ipfire.org/gitweb/index.cgi?a=commitdiff_plain;h=79f44c8acfe66ff8cbed5626e2535245cfcf43cf;p=thirdparty%2Fkernel%2Flinux.git gpio: add GPIO controller found on Waveshare DSI TOUCH panels 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 Reviewed-by: Linus Walleij Signed-off-by: Dmitry Baryshkov Link: https://patch.msgid.link/20260507-waveshare-dsi-touch-v5-2-d2ac7ccc22d4@oss.qualcomm.com Signed-off-by: Bartosz Golaszewski --- diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig index ce95a25298a8c..8ae6a423da6d5 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 b267598b517de..2ea47d9d3dca9 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 0000000000000..38f52351bb584 --- /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 +#include +#include +#include +#include +#include +#include + +/* 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");