Add a driver for the ESWIN EPH8621 touchscreens, connected via SPI. The driver this is based on - EPH861X - also supports I2C but this is not added the Fairphone (Gen. 6) has the touchscreen connected via SPI.
Assisted-by: Gemini:gemini-3.1-pro Signed-off-by: Luca Weiss <[email protected]> --- drivers/input/touchscreen/Kconfig | 12 ++ drivers/input/touchscreen/Makefile | 1 + drivers/input/touchscreen/eswin_eph8621.c | 310 ++++++++++++++++++++++++++++++ 3 files changed, 323 insertions(+) diff --git a/drivers/input/touchscreen/Kconfig b/drivers/input/touchscreen/Kconfig index 9b9ae8ac3f7f..007b589cef8e 100644 --- a/drivers/input/touchscreen/Kconfig +++ b/drivers/input/touchscreen/Kconfig @@ -360,6 +360,18 @@ config TOUCHSCREEN_EGALAX_SERIAL To compile this driver as a module, choose M here: the module will be called egalax_ts_serial. +config TOUCHSCREEN_ESWIN_EPH8621 + tristate "ESWIN EPH8621 touchscreen" + depends on SPI_MASTER + help + Say Y here if you have a ESWIN EPH8621 connected to + your system via SPI. + + If unsure, say N. + + To compile this driver as a module, choose M here: the + module will be called eswin_eph8621. + config TOUCHSCREEN_EXC3000 tristate "EETI EXC3000 multi-touch panel support" depends on I2C diff --git a/drivers/input/touchscreen/Makefile b/drivers/input/touchscreen/Makefile index bfd9de83389d..4540169d9b54 100644 --- a/drivers/input/touchscreen/Makefile +++ b/drivers/input/touchscreen/Makefile @@ -42,6 +42,7 @@ obj-$(CONFIG_TOUCHSCREEN_ELAN) += elants_i2c.o obj-$(CONFIG_TOUCHSCREEN_ELO) += elo.o obj-$(CONFIG_TOUCHSCREEN_EGALAX) += egalax_ts.o obj-$(CONFIG_TOUCHSCREEN_EGALAX_SERIAL) += egalax_ts_serial.o +obj-$(CONFIG_TOUCHSCREEN_ESWIN_EPH8621) += eswin_eph8621.o obj-$(CONFIG_TOUCHSCREEN_EXC3000) += exc3000.o obj-$(CONFIG_TOUCHSCREEN_FUJITSU) += fujitsu_ts.o obj-$(CONFIG_TOUCHSCREEN_GOODIX) += goodix_ts.o diff --git a/drivers/input/touchscreen/eswin_eph8621.c b/drivers/input/touchscreen/eswin_eph8621.c new file mode 100644 index 000000000000..12b90cc89052 --- /dev/null +++ b/drivers/input/touchscreen/eswin_eph8621.c @@ -0,0 +1,310 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * ESWIN EPH8621 series touchscreen driver + * + * Copyright (C) 2026 Luca Weiss <[email protected]> + * + * Based on original EPH861X driver by [email protected] + */ + +#include <linux/delay.h> +#include <linux/gpio/consumer.h> +#include <linux/input.h> +#include <linux/input/mt.h> +#include <linux/input/touchscreen.h> +#include <linux/interrupt.h> +#include <linux/module.h> +#include <linux/regulator/consumer.h> +#include <linux/sizes.h> +#include <linux/spi/spi.h> + +#define ESWIN_MAX_TOUCHES 10 +#define ESWIN_COMMS_BUF_SIZE 3072 + +/* TLV Protocol Definitions */ +#define TLV_HEADER_SIZE 3 /* 1 byte Type + 2 bytes Length */ +#define TLV_TYPE_FIELD 0 +#define TLV_LENGTH_FIELD 1 + +#define TLV_REPORT_DATA 0x23 +#define EVENT_REPORT_TYPE_OFFSET 4 +#define EVENT_REPORT_TYPE_MASK 0xF0 +#define EVENT_REPORT_LENGTH_MASK 0x0F + +/* Event Types */ +#define CONTACT_TYPE 1 +#define RELEASE_TYPE 2 + +struct eswin_touch { + struct device *dev; + struct input_dev *input; + + struct gpio_desc *reset_gpio; + struct regulator_bulk_data supplies[2]; + + struct touchscreen_properties prop; + + u8 *rx_buf; + u8 *tx_buf; +}; + +static int eswin_spi_read(struct eswin_touch *ts, u16 len, u8 *buf) +{ + struct spi_device *spi = to_spi_device(ts->dev); + struct spi_transfer xfer = { + .tx_buf = ts->tx_buf, + .rx_buf = ts->rx_buf, + .len = len, + }; + int error; + + if (len > ESWIN_COMMS_BUF_SIZE) + return -EINVAL; + + /* ESWIN requires 0xFF dummy bytes clocked out to read data */ + memset(ts->tx_buf, 0xFF, len); + error = spi_sync_transfer(spi, &xfer, 1); + if (error) + return error; + + memcpy(buf, ts->rx_buf, len); + return 0; +} + +/* + * Core Touch Handling + */ +static int eswin_comms_two_stage_read(struct eswin_touch *ts, u8 *buf) +{ + u16 payload_len; + int error; + + /* Stage 1: Read 3-byte header */ + error = eswin_spi_read(ts, TLV_HEADER_SIZE, buf); + if (error) + return error; + + payload_len = buf[TLV_LENGTH_FIELD] | (buf[TLV_LENGTH_FIELD + 1] << 8); + if (payload_len == 0 || payload_len > ESWIN_COMMS_BUF_SIZE - TLV_HEADER_SIZE) + return -EINVAL; + + udelay(50); + + /* Stage 2: Read full packet (Header + Payload) */ + return eswin_spi_read(ts, payload_len + TLV_HEADER_SIZE, buf); +} + +static void eswin_report_contact(struct eswin_touch *ts, u8 *payload) +{ + u8 touch_type = (payload[0] & EVENT_REPORT_TYPE_MASK) >> EVENT_REPORT_TYPE_OFFSET; + u8 slot = payload[1]; + u16 x = payload[2] | (payload[3] << 8); + u16 y = payload[4] | (payload[5] << 8); + u8 width = payload[6]; + u8 height = payload[7]; + bool active = false; + + switch (touch_type) { + case CONTACT_TYPE: + active = true; + break; + case RELEASE_TYPE: + active = false; + break; + default: + dev_warn_ratelimited(ts->dev, "Unhandled touch type: %d\n", touch_type); + return; + } + + input_mt_slot(ts->input, slot); + input_mt_report_slot_state(ts->input, MT_TOOL_FINGER, active); + + if (active) { + touchscreen_report_pos(ts->input, &ts->prop, x, y, true); + input_report_abs(ts->input, ABS_MT_TOUCH_MAJOR, height); + input_report_abs(ts->input, ABS_MT_TOUCH_MINOR, width); + } +} + +static void eswin_process_report(struct eswin_touch *ts, u8 *buf) +{ + u16 total_len = buf[TLV_LENGTH_FIELD] | (buf[TLV_LENGTH_FIELD + 1] << 8); + u16 offset = TLV_HEADER_SIZE; + + if (buf[TLV_TYPE_FIELD] != TLV_REPORT_DATA) + return; + + while (offset < total_len + TLV_HEADER_SIZE) { + u8 ev_len = buf[offset] & EVENT_REPORT_LENGTH_MASK; + + eswin_report_contact(ts, &buf[offset]); + offset += (ev_len + 1); + } + + input_mt_sync_frame(ts->input); + input_sync(ts->input); +} + +static irqreturn_t eswin_interrupt(int irq, void *dev_id) +{ + struct eswin_touch *ts = dev_id; + int error; + + error = eswin_comms_two_stage_read(ts, ts->rx_buf); + if (!error) + eswin_process_report(ts, ts->rx_buf); + + return IRQ_HANDLED; +} + +static int eswin_power_on(struct eswin_touch *ts) +{ + int error; + + error = regulator_bulk_enable(ARRAY_SIZE(ts->supplies), ts->supplies); + if (error) + return error; + + msleep(150); + gpiod_set_value_cansleep(ts->reset_gpio, 0); + msleep(100); + + return 0; +} + +static void eswin_power_off(struct eswin_touch *ts) +{ + gpiod_set_value_cansleep(ts->reset_gpio, 1); + regulator_bulk_disable(ARRAY_SIZE(ts->supplies), ts->supplies); +} + +static void eswin_power_off_act(void *data) +{ + struct eswin_touch *ts = data; + + eswin_power_off(ts); +} + +static int eswin_probe(struct spi_device *spi) +{ + struct device *dev = &spi->dev; + struct eswin_touch *ts; + int error; + + ts = devm_kzalloc(dev, sizeof(*ts), GFP_KERNEL); + if (!ts) + return -ENOMEM; + + ts->dev = dev; + spi_set_drvdata(spi, ts); + + spi->mode = SPI_MODE_3; + spi->bits_per_word = 8; + error = spi_setup(spi); + if (error) + return dev_err_probe(dev, error, "Failed to setup SPI\n"); + + ts->rx_buf = devm_kzalloc(dev, ESWIN_COMMS_BUF_SIZE, GFP_KERNEL); + ts->tx_buf = devm_kzalloc(dev, ESWIN_COMMS_BUF_SIZE, GFP_KERNEL); + if (!ts->rx_buf || !ts->tx_buf) + return -ENOMEM; + + ts->supplies[0].supply = "vddio"; + ts->supplies[1].supply = "avdd"; + error = devm_regulator_bulk_get(dev, ARRAY_SIZE(ts->supplies), ts->supplies); + if (error) + return dev_err_probe(dev, error, "Failed to get regulators\n"); + + ts->reset_gpio = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH); + if (IS_ERR(ts->reset_gpio)) + return dev_err_probe(dev, PTR_ERR(ts->reset_gpio), + "Failed to request reset GPIO\n"); + + error = eswin_power_on(ts); + if (error) + return dev_err_probe(dev, error, "Failed to power on\n"); + + error = devm_add_action_or_reset(dev, eswin_power_off_act, ts); + if (error) + return error; + + ts->input = devm_input_allocate_device(dev); + if (!ts->input) + return -ENOMEM; + + ts->input->name = "ESWIN Touchscreen"; + ts->input->id.bustype = BUS_SPI; + + input_set_abs_params(ts->input, ABS_MT_POSITION_X, 0, SZ_64K - 1, 0, 0); + input_set_abs_params(ts->input, ABS_MT_POSITION_Y, 0, SZ_64K - 1, 0, 0); + input_set_abs_params(ts->input, ABS_MT_TOUCH_MAJOR, 0, 255, 0, 0); + input_set_abs_params(ts->input, ABS_MT_TOUCH_MINOR, 0, 255, 0, 0); + + touchscreen_parse_properties(ts->input, true, &ts->prop); + + error = input_mt_init_slots(ts->input, ESWIN_MAX_TOUCHES, INPUT_MT_DIRECT); + if (error) + return dev_err_probe(dev, error, "Failed to initialize MT slots\n"); + + error = devm_request_threaded_irq(dev, spi->irq, NULL, eswin_interrupt, + IRQF_ONESHOT, dev_name(dev), ts); + if (error) + return dev_err_probe(dev, error, "Failed to request IRQ\n"); + + return input_register_device(ts->input); +} + +static int eswin_suspend(struct device *dev) +{ + struct spi_device *spi = to_spi_device(dev); + struct eswin_touch *ts = spi_get_drvdata(spi); + + disable_irq(spi->irq); + eswin_power_off(ts); + + return 0; +} + +static int eswin_resume(struct device *dev) +{ + struct spi_device *spi = to_spi_device(dev); + struct eswin_touch *ts = spi_get_drvdata(spi); + int error; + + error = eswin_power_on(ts); + if (error) + return error; + + enable_irq(spi->irq); + + return 0; +} + +static DEFINE_SIMPLE_DEV_PM_OPS(eswin_pm_ops, eswin_suspend, eswin_resume); + +static const struct of_device_id eswin_of_match[] = { + { .compatible = "eswin,eph8621" }, + { } +}; +MODULE_DEVICE_TABLE(of, eswin_of_match); + +static const struct spi_device_id eswin_spi_id[] = { + { .name = "eph8621" }, + { } +}; +MODULE_DEVICE_TABLE(spi, eswin_spi_id); + +static struct spi_driver eswin_spi_driver = { + .driver = { + .name = "eswin_eph8621", + .of_match_table = eswin_of_match, + .pm = pm_sleep_ptr(&eswin_pm_ops), + }, + .probe = eswin_probe, + .id_table = eswin_spi_id, +}; +module_spi_driver(eswin_spi_driver); + +MODULE_AUTHOR("Luca Weiss <[email protected]>"); +MODULE_DESCRIPTION("ESWIN EPH8621 SPI touchscreen driver"); +MODULE_LICENSE("GPL"); -- 2.55.0
