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Input: goodix-berlin - add SPI support for Goodix Berlin Touchscreen IC
Add initial support for the new Goodix "Berlin" touchscreen ICs over the SPI interface. The driver doesn't use the regmap_spi code since the SPI messages needs to be prefixed, thus this custom regmap code. This initial driver is derived from the Goodix goodix_ts_berlin available at [1] and [2] and only supports the GT9916 IC present on the Qualcomm SM8550 MTP & QRD touch panel. The current implementation only supports BerlinD, aka GT9916. [1] https://github.com/goodix/goodix_ts_berlin [2] https://git.codelinaro.org/clo/la/platform/vendor/opensource/touch-drivers Reviewed-by: Jeff LaBundy <jeff@labundy.com> Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org> Link: https://lore.kernel.org/r/20240129-topic-goodix-berlin-upstream-initial-v15-4-6f7d096c0a0a@linaro.org Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
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‎drivers/input/touchscreen/Kconfig

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@@ -433,6 +433,20 @@ config TOUCHSCREEN_GOODIX_BERLIN_I2C
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To compile this driver as a module, choose M here: the
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module will be called goodix_berlin_i2c.
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config TOUCHSCREEN_GOODIX_BERLIN_SPI
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tristate "Goodix Berlin SPI touchscreen"
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depends on SPI_MASTER
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select REGMAP
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select TOUCHSCREEN_GOODIX_BERLIN_CORE
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help
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Say Y here if you have a Goodix Berlin IC connected to
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your system via SPI.
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If unsure, say N.
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To compile this driver as a module, choose M here: the
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module will be called goodix_berlin_spi.
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config TOUCHSCREEN_HIDEEP
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tristate "HiDeep Touch IC"
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depends on I2C

‎drivers/input/touchscreen/Makefile

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@@ -49,6 +49,7 @@ obj-$(CONFIG_TOUCHSCREEN_FUJITSU) += fujitsu_ts.o
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obj-$(CONFIG_TOUCHSCREEN_GOODIX) += goodix_ts.o
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obj-$(CONFIG_TOUCHSCREEN_GOODIX_BERLIN_CORE) += goodix_berlin_core.o
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obj-$(CONFIG_TOUCHSCREEN_GOODIX_BERLIN_I2C) += goodix_berlin_i2c.o
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obj-$(CONFIG_TOUCHSCREEN_GOODIX_BERLIN_SPI) += goodix_berlin_spi.o
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obj-$(CONFIG_TOUCHSCREEN_HIDEEP) += hideep.o
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obj-$(CONFIG_TOUCHSCREEN_HYNITRON_CSTXXX) += hynitron_cstxxx.o
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obj-$(CONFIG_TOUCHSCREEN_ILI210X) += ili210x.o

‎drivers/input/touchscreen/goodix_berlin_spi.c

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// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* Goodix Berlin Touchscreen Driver
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*
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* Copyright (C) 2020 - 2021 Goodix, Inc.
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* Copyright (C) 2023 Linaro Ltd.
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*
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* Based on goodix_ts_berlin driver.
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*/
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#include <asm/unaligned.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/regmap.h>
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#include <linux/spi/spi.h>
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#include <linux/input.h>
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#include "goodix_berlin.h"
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#define GOODIX_BERLIN_SPI_TRANS_PREFIX_LEN 1
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#define GOODIX_BERLIN_REGISTER_WIDTH 4
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#define GOODIX_BERLIN_SPI_READ_DUMMY_LEN 3
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#define GOODIX_BERLIN_SPI_READ_PREFIX_LEN (GOODIX_BERLIN_SPI_TRANS_PREFIX_LEN + \
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GOODIX_BERLIN_REGISTER_WIDTH + \
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GOODIX_BERLIN_SPI_READ_DUMMY_LEN)
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#define GOODIX_BERLIN_SPI_WRITE_PREFIX_LEN (GOODIX_BERLIN_SPI_TRANS_PREFIX_LEN + \
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GOODIX_BERLIN_REGISTER_WIDTH)
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#define GOODIX_BERLIN_SPI_WRITE_FLAG 0xF0
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#define GOODIX_BERLIN_SPI_READ_FLAG 0xF1
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static int goodix_berlin_spi_read(void *context, const void *reg_buf,
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size_t reg_size, void *val_buf,
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size_t val_size)
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{
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struct spi_device *spi = context;
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struct spi_transfer xfers;
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struct spi_message spi_msg;
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const u32 *reg = reg_buf; /* reg is stored as native u32 at start of buffer */
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u8 *buf;
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int error;
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if (reg_size != GOODIX_BERLIN_REGISTER_WIDTH)
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return -EINVAL;
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buf = kzalloc(GOODIX_BERLIN_SPI_READ_PREFIX_LEN + val_size, GFP_KERNEL);
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if (!buf)
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return -ENOMEM;
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spi_message_init(&spi_msg);
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memset(&xfers, 0, sizeof(xfers));
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/* buffer format: 0xF1 + addr(4bytes) + dummy(3bytes) + data */
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buf[0] = GOODIX_BERLIN_SPI_READ_FLAG;
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put_unaligned_be32(*reg, buf + GOODIX_BERLIN_SPI_TRANS_PREFIX_LEN);
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memset(buf + GOODIX_BERLIN_SPI_TRANS_PREFIX_LEN + GOODIX_BERLIN_REGISTER_WIDTH,
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0xff, GOODIX_BERLIN_SPI_READ_DUMMY_LEN);
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xfers.tx_buf = buf;
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xfers.rx_buf = buf;
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xfers.len = GOODIX_BERLIN_SPI_READ_PREFIX_LEN + val_size;
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xfers.cs_change = 0;
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spi_message_add_tail(&xfers, &spi_msg);
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error = spi_sync(spi, &spi_msg);
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if (error < 0)
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dev_err(&spi->dev, "spi transfer error, %d", error);
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else
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memcpy(val_buf, buf + GOODIX_BERLIN_SPI_READ_PREFIX_LEN, val_size);
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kfree(buf);
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return error;
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}
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static int goodix_berlin_spi_write(void *context, const void *data,
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size_t count)
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{
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unsigned int len = count - GOODIX_BERLIN_REGISTER_WIDTH;
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struct spi_device *spi = context;
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struct spi_transfer xfers;
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struct spi_message spi_msg;
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const u32 *reg = data; /* reg is stored as native u32 at start of buffer */
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u8 *buf;
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int error;
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buf = kzalloc(GOODIX_BERLIN_SPI_WRITE_PREFIX_LEN + len, GFP_KERNEL);
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if (!buf)
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return -ENOMEM;
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spi_message_init(&spi_msg);
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memset(&xfers, 0, sizeof(xfers));
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buf[0] = GOODIX_BERLIN_SPI_WRITE_FLAG;
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put_unaligned_be32(*reg, buf + GOODIX_BERLIN_SPI_TRANS_PREFIX_LEN);
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memcpy(buf + GOODIX_BERLIN_SPI_WRITE_PREFIX_LEN,
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data + GOODIX_BERLIN_REGISTER_WIDTH, len);
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xfers.tx_buf = buf;
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xfers.len = GOODIX_BERLIN_SPI_WRITE_PREFIX_LEN + len;
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xfers.cs_change = 0;
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spi_message_add_tail(&xfers, &spi_msg);
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error = spi_sync(spi, &spi_msg);
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if (error < 0)
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dev_err(&spi->dev, "spi transfer error, %d", error);
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kfree(buf);
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return error;
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}
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static const struct regmap_config goodix_berlin_spi_regmap_conf = {
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.reg_bits = 32,
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.val_bits = 8,
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.read = goodix_berlin_spi_read,
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.write = goodix_berlin_spi_write,
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};
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/* vendor & product left unassigned here, should probably be updated from fw info */
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static const struct input_id goodix_berlin_spi_input_id = {
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.bustype = BUS_SPI,
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};
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static int goodix_berlin_spi_probe(struct spi_device *spi)
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{
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struct regmap_config regmap_config;
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struct regmap *regmap;
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size_t max_size;
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int error = 0;
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spi->mode = SPI_MODE_0;
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spi->bits_per_word = 8;
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error = spi_setup(spi);
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if (error)
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return error;
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max_size = spi_max_transfer_size(spi);
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regmap_config = goodix_berlin_spi_regmap_conf;
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regmap_config.max_raw_read = max_size - GOODIX_BERLIN_SPI_READ_PREFIX_LEN;
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regmap_config.max_raw_write = max_size - GOODIX_BERLIN_SPI_WRITE_PREFIX_LEN;
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regmap = devm_regmap_init(&spi->dev, NULL, spi, &regmap_config);
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if (IS_ERR(regmap))
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return PTR_ERR(regmap);
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error = goodix_berlin_probe(&spi->dev, spi->irq,
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&goodix_berlin_spi_input_id, regmap);
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if (error)
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return error;
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return 0;
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}
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static const struct spi_device_id goodix_berlin_spi_ids[] = {
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{ "gt9916" },
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{ },
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};
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MODULE_DEVICE_TABLE(spi, goodix_berlin_spi_ids);
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static const struct of_device_id goodix_berlin_spi_of_match[] = {
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{ .compatible = "goodix,gt9916", },
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{ }
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};
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MODULE_DEVICE_TABLE(of, goodix_berlin_spi_of_match);
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static struct spi_driver goodix_berlin_spi_driver = {
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.driver = {
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.name = "goodix-berlin-spi",
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.of_match_table = goodix_berlin_spi_of_match,
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.pm = pm_sleep_ptr(&goodix_berlin_pm_ops),
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},
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.probe = goodix_berlin_spi_probe,
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.id_table = goodix_berlin_spi_ids,
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};
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module_spi_driver(goodix_berlin_spi_driver);
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MODULE_LICENSE("GPL");
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MODULE_DESCRIPTION("Goodix Berlin SPI Touchscreen driver");
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MODULE_AUTHOR("Neil Armstrong <neil.armstrong@linaro.org>");

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