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// 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 <asm/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 3
#define GOODIX_BERLIN_SPI_READ_PREFIX_LEN (GOODIX_BERLIN_SPI_TRANS_PREFIX_LEN + \
GOODIX_BERLIN_REGISTER_WIDTH + \
GOODIX_BERLIN_SPI_READ_DUMMY_LEN)
#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;
struct spi_transfer xfers;
struct spi_message spi_msg;
const u32 *reg = reg_buf; /* reg is stored as native u32 at start of buffer */
u8 *buf;
int error;
if (reg_size != GOODIX_BERLIN_REGISTER_WIDTH)
return -EINVAL;
buf = kzalloc(GOODIX_BERLIN_SPI_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(3bytes) + 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, GOODIX_BERLIN_SPI_READ_DUMMY_LEN);
xfers.tx_buf = buf;
xfers.rx_buf = buf;
xfers.len = GOODIX_BERLIN_SPI_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);
else
memcpy(val_buf, buf + GOODIX_BERLIN_SPI_READ_PREFIX_LEN, val_size);
kfree(buf);
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 */
u8 *buf;
int error;
buf = kzalloc(GOODIX_BERLIN_SPI_WRITE_PREFIX_LEN + len, GFP_KERNEL);
if (!buf)
return -ENOMEM;
spi_message_init(&spi_msg);
memset(&xfers, 0, sizeof(xfers));
buf[0] = GOODIX_BERLIN_SPI_WRITE_FLAG;
put_unaligned_be32(*reg, buf + GOODIX_BERLIN_SPI_TRANS_PREFIX_LEN);
memcpy(buf + GOODIX_BERLIN_SPI_WRITE_PREFIX_LEN,
data + GOODIX_BERLIN_REGISTER_WIDTH, len);
xfers.tx_buf = buf;
xfers.len = GOODIX_BERLIN_SPI_WRITE_PREFIX_LEN + len;
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);
kfree(buf);
return error;
}
static const struct regmap_config goodix_berlin_spi_regmap_conf = {
.reg_bits = 32,
.val_bits = 8,
.read = goodix_berlin_spi_read,
.write = goodix_berlin_spi_write,
};
/* vendor & product left unassigned here, should probably be updated from fw info */
static const struct input_id goodix_berlin_spi_input_id = {
.bustype = BUS_SPI,
};
static int goodix_berlin_spi_probe(struct spi_device *spi)
{
struct regmap_config regmap_config;
struct regmap *regmap;
size_t max_size;
int error = 0;
spi->mode = SPI_MODE_0;
spi->bits_per_word = 8;
error = spi_setup(spi);
if (error)
return error;
max_size = spi_max_transfer_size(spi);
regmap_config = goodix_berlin_spi_regmap_conf;
regmap_config.max_raw_read = max_size - GOODIX_BERLIN_SPI_READ_PREFIX_LEN;
regmap_config.max_raw_write = max_size - GOODIX_BERLIN_SPI_WRITE_PREFIX_LEN;
regmap = devm_regmap_init(&spi->dev, NULL, spi, ®map_config);
if (IS_ERR(regmap))
return PTR_ERR(regmap);
error = goodix_berlin_probe(&spi->dev, spi->irq,
&goodix_berlin_spi_input_id, regmap);
if (error)
return error;
return 0;
}
static const struct spi_device_id goodix_berlin_spi_ids[] = {
{ "gt9916" },
{ },
};
MODULE_DEVICE_TABLE(spi, goodix_berlin_spi_ids);
static const struct of_device_id goodix_berlin_spi_of_match[] = {
{ .compatible = "goodix,gt9916", },
{ }
};
MODULE_DEVICE_TABLE(of, goodix_berlin_spi_of_match);
static struct spi_driver goodix_berlin_spi_driver = {
.driver = {
.name = "goodix-berlin-spi",
.of_match_table = goodix_berlin_spi_of_match,
.pm = pm_sleep_ptr(&goodix_berlin_pm_ops),
},
.probe = goodix_berlin_spi_probe,
.id_table = goodix_berlin_spi_ids,
};
module_spi_driver(goodix_berlin_spi_driver);
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Goodix Berlin SPI Touchscreen driver");
MODULE_AUTHOR("Neil Armstrong <neil.armstrong@linaro.org>");
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