drivers/input/touchscreen/goodix_berlin_spi.c

Source file repositories/reference/linux-study-clean/drivers/input/touchscreen/goodix_berlin_spi.c

File Facts

System
Linux kernel
Corpus path
drivers/input/touchscreen/goodix_berlin_spi.c
Extension
.c
Size
6154 bytes
Lines
204
Domain
Driver Families
Bucket
drivers/input
Inferred role
Driver Families: implementation source
Status
source implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

Dependency Surface

Detected Declarations

Annotated Snippet

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Goodix Berlin Touchscreen Driver
 *
 * Copyright (C) 2020 - 2021 Goodix, Inc.
 * Copyright (C) 2023 Linaro Ltd.
 *
 * Based on goodix_ts_berlin driver.
 */
#include <linux/unaligned.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/regmap.h>
#include <linux/spi/spi.h>
#include <linux/input.h>

#include "goodix_berlin.h"

#define GOODIX_BERLIN_SPI_TRANS_PREFIX_LEN	1
#define GOODIX_BERLIN_REGISTER_WIDTH		4
#define GOODIX_BERLIN_SPI_READ_DUMMY_LEN_A	4
#define GOODIX_BERLIN_SPI_READ_DUMMY_LEN_D	3
#define GOODIX_BERLIN_SPI_READ_PREFIX_LEN_A	(GOODIX_BERLIN_SPI_TRANS_PREFIX_LEN + \
						 GOODIX_BERLIN_REGISTER_WIDTH + \
						 GOODIX_BERLIN_SPI_READ_DUMMY_LEN_A)
#define GOODIX_BERLIN_SPI_READ_PREFIX_LEN_D	(GOODIX_BERLIN_SPI_TRANS_PREFIX_LEN + \
						 GOODIX_BERLIN_REGISTER_WIDTH + \
						 GOODIX_BERLIN_SPI_READ_DUMMY_LEN_D)
#define GOODIX_BERLIN_SPI_WRITE_PREFIX_LEN	(GOODIX_BERLIN_SPI_TRANS_PREFIX_LEN + \
						 GOODIX_BERLIN_REGISTER_WIDTH)

#define GOODIX_BERLIN_SPI_WRITE_FLAG		0xF0
#define GOODIX_BERLIN_SPI_READ_FLAG		0xF1

static int goodix_berlin_spi_read(void *context, const void *reg_buf,
				  size_t reg_size, void *val_buf,
				  size_t val_size)
{
	struct spi_device *spi = context;
	const struct goodix_berlin_ic_data *ic_data = spi_get_device_match_data(spi);
	struct spi_transfer xfers;
	struct spi_message spi_msg;
	const u32 *reg = reg_buf; /* reg is stored as native u32 at start of buffer */
	int error;

	if (reg_size != GOODIX_BERLIN_REGISTER_WIDTH)
		return -EINVAL;

	u8 *buf __free(kfree) =
		kzalloc(ic_data->read_prefix_len + val_size, GFP_KERNEL);
	if (!buf)
		return -ENOMEM;

	spi_message_init(&spi_msg);
	memset(&xfers, 0, sizeof(xfers));

	/* buffer format: 0xF1 + addr(4bytes) + dummy(3/4bytes) + data */
	buf[0] = GOODIX_BERLIN_SPI_READ_FLAG;
	put_unaligned_be32(*reg, buf + GOODIX_BERLIN_SPI_TRANS_PREFIX_LEN);
	memset(buf + GOODIX_BERLIN_SPI_TRANS_PREFIX_LEN + GOODIX_BERLIN_REGISTER_WIDTH,
	       0xff, ic_data->read_dummy_len);

	xfers.tx_buf = buf;
	xfers.rx_buf = buf;
	xfers.len = ic_data->read_prefix_len + val_size;
	xfers.cs_change = 0;
	spi_message_add_tail(&xfers, &spi_msg);

	error = spi_sync(spi, &spi_msg);
	if (error < 0) {
		dev_err(&spi->dev, "spi transfer error, %d", error);
		return error;
	}

	memcpy(val_buf, buf + ic_data->read_prefix_len, val_size);
	return error;
}

static int goodix_berlin_spi_write(void *context, const void *data,
				   size_t count)
{
	unsigned int len = count - GOODIX_BERLIN_REGISTER_WIDTH;
	struct spi_device *spi = context;
	struct spi_transfer xfers;
	struct spi_message spi_msg;
	const u32 *reg = data; /* reg is stored as native u32 at start of buffer */
	int error;

	u8 *buf __free(kfree) =
		kzalloc(GOODIX_BERLIN_SPI_WRITE_PREFIX_LEN + len, GFP_KERNEL);

Annotation

Implementation Notes