1// SPDX-License-Identifier: GPL-2.0-or-later
  2/*
  3 * Goodix Berlin Touchscreen Driver
  4 *
  5 * Copyright (C) 2020 - 2021 Goodix, Inc.
  6 * Copyright (C) 2023 Linaro Ltd.
  7 *
  8 * Based on goodix_ts_berlin driver.
  9 */
 10#include <linux/unaligned.h>
 11#include <linux/kernel.h>
 12#include <linux/module.h>
 13#include <linux/regmap.h>
 14#include <linux/spi/spi.h>
 15#include <linux/input.h>
 16
 17#include "goodix_berlin.h"
 18
 19#define GOODIX_BERLIN_SPI_TRANS_PREFIX_LEN	1
 20#define GOODIX_BERLIN_REGISTER_WIDTH		4
 21#define GOODIX_BERLIN_SPI_READ_DUMMY_LEN	3
 22#define GOODIX_BERLIN_SPI_READ_PREFIX_LEN	(GOODIX_BERLIN_SPI_TRANS_PREFIX_LEN + \
 23						 GOODIX_BERLIN_REGISTER_WIDTH + \
 24						 GOODIX_BERLIN_SPI_READ_DUMMY_LEN)
 25#define GOODIX_BERLIN_SPI_WRITE_PREFIX_LEN	(GOODIX_BERLIN_SPI_TRANS_PREFIX_LEN + \
 26						 GOODIX_BERLIN_REGISTER_WIDTH)
 27
 28#define GOODIX_BERLIN_SPI_WRITE_FLAG		0xF0
 29#define GOODIX_BERLIN_SPI_READ_FLAG		0xF1
 30
 31static int goodix_berlin_spi_read(void *context, const void *reg_buf,
 32				  size_t reg_size, void *val_buf,
 33				  size_t val_size)
 34{
 35	struct spi_device *spi = context;
 36	struct spi_transfer xfers;
 37	struct spi_message spi_msg;
 38	const u32 *reg = reg_buf; /* reg is stored as native u32 at start of buffer */
 39	int error;
 40
 41	if (reg_size != GOODIX_BERLIN_REGISTER_WIDTH)
 42		return -EINVAL;
 43
 44	u8 *buf __free(kfree) =
 45		kzalloc(GOODIX_BERLIN_SPI_READ_PREFIX_LEN + val_size,
 46			GFP_KERNEL);
 47	if (!buf)
 48		return -ENOMEM;
 49
 50	spi_message_init(&spi_msg);
 51	memset(&xfers, 0, sizeof(xfers));
 52
 53	/* buffer format: 0xF1 + addr(4bytes) + dummy(3bytes) + data */
 54	buf[0] = GOODIX_BERLIN_SPI_READ_FLAG;
 55	put_unaligned_be32(*reg, buf + GOODIX_BERLIN_SPI_TRANS_PREFIX_LEN);
 56	memset(buf + GOODIX_BERLIN_SPI_TRANS_PREFIX_LEN + GOODIX_BERLIN_REGISTER_WIDTH,
 57	       0xff, GOODIX_BERLIN_SPI_READ_DUMMY_LEN);
 58
 59	xfers.tx_buf = buf;
 60	xfers.rx_buf = buf;
 61	xfers.len = GOODIX_BERLIN_SPI_READ_PREFIX_LEN + val_size;
 62	xfers.cs_change = 0;
 63	spi_message_add_tail(&xfers, &spi_msg);
 64
 65	error = spi_sync(spi, &spi_msg);
 66	if (error < 0) {
 67		dev_err(&spi->dev, "spi transfer error, %d", error);
 68		return error;
 69	}
 70
 71	memcpy(val_buf, buf + GOODIX_BERLIN_SPI_READ_PREFIX_LEN, val_size);
 72	return error;
 73}
 74
 75static int goodix_berlin_spi_write(void *context, const void *data,
 76				   size_t count)
 77{
 78	unsigned int len = count - GOODIX_BERLIN_REGISTER_WIDTH;
 79	struct spi_device *spi = context;
 80	struct spi_transfer xfers;
 81	struct spi_message spi_msg;
 82	const u32 *reg = data; /* reg is stored as native u32 at start of buffer */
 83	int error;
 84
 85	u8 *buf __free(kfree) =
 86		kzalloc(GOODIX_BERLIN_SPI_WRITE_PREFIX_LEN + len, GFP_KERNEL);
 87	if (!buf)
 88		return -ENOMEM;
 89
 90	spi_message_init(&spi_msg);
 91	memset(&xfers, 0, sizeof(xfers));
 92
 93	buf[0] = GOODIX_BERLIN_SPI_WRITE_FLAG;
 94	put_unaligned_be32(*reg, buf + GOODIX_BERLIN_SPI_TRANS_PREFIX_LEN);
 95	memcpy(buf + GOODIX_BERLIN_SPI_WRITE_PREFIX_LEN,
 96	       data + GOODIX_BERLIN_REGISTER_WIDTH, len);
 97
 98	xfers.tx_buf = buf;
 99	xfers.len = GOODIX_BERLIN_SPI_WRITE_PREFIX_LEN + len;
100	xfers.cs_change = 0;
101	spi_message_add_tail(&xfers, &spi_msg);
102
103	error = spi_sync(spi, &spi_msg);
104	if (error < 0) {
105		dev_err(&spi->dev, "spi transfer error, %d", error);
106		return error;
107	}
108
109	return 0;
110}
111
112static const struct regmap_config goodix_berlin_spi_regmap_conf = {
113	.reg_bits = 32,
114	.val_bits = 8,
115	.read = goodix_berlin_spi_read,
116	.write = goodix_berlin_spi_write,
117};
118
119/* vendor & product left unassigned here, should probably be updated from fw info */
120static const struct input_id goodix_berlin_spi_input_id = {
121	.bustype = BUS_SPI,
122};
123
124static int goodix_berlin_spi_probe(struct spi_device *spi)
125{
126	struct regmap_config regmap_config;
127	struct regmap *regmap;
128	size_t max_size;
129	int error = 0;
130
131	spi->mode = SPI_MODE_0;
132	spi->bits_per_word = 8;
133	error = spi_setup(spi);
134	if (error)
135		return error;
136
137	max_size = spi_max_transfer_size(spi);
138
139	regmap_config = goodix_berlin_spi_regmap_conf;
140	regmap_config.max_raw_read = max_size - GOODIX_BERLIN_SPI_READ_PREFIX_LEN;
141	regmap_config.max_raw_write = max_size - GOODIX_BERLIN_SPI_WRITE_PREFIX_LEN;
142
143	regmap = devm_regmap_init(&spi->dev, NULL, spi, &regmap_config);
144	if (IS_ERR(regmap))
145		return PTR_ERR(regmap);
146
147	error = goodix_berlin_probe(&spi->dev, spi->irq,
148				    &goodix_berlin_spi_input_id, regmap);
149	if (error)
150		return error;
151
152	return 0;
153}
154
155static const struct spi_device_id goodix_berlin_spi_ids[] = {
156	{ "gt9916" },
157	{ },
158};
159MODULE_DEVICE_TABLE(spi, goodix_berlin_spi_ids);
160
161static const struct of_device_id goodix_berlin_spi_of_match[] = {
162	{ .compatible = "goodix,gt9916", },
163	{ }
164};
165MODULE_DEVICE_TABLE(of, goodix_berlin_spi_of_match);
166
167static struct spi_driver goodix_berlin_spi_driver = {
168	.driver = {
169		.name = "goodix-berlin-spi",
170		.of_match_table = goodix_berlin_spi_of_match,
171		.pm = pm_sleep_ptr(&goodix_berlin_pm_ops),
172		.dev_groups = goodix_berlin_groups,
173	},
174	.probe = goodix_berlin_spi_probe,
175	.id_table = goodix_berlin_spi_ids,
176};
177module_spi_driver(goodix_berlin_spi_driver);
178
179MODULE_LICENSE("GPL");
180MODULE_DESCRIPTION("Goodix Berlin SPI Touchscreen driver");
181MODULE_AUTHOR("Neil Armstrong <neil.armstrong@linaro.org>");