goodix_berlin_spi.c

  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_A	4
 22#define GOODIX_BERLIN_SPI_READ_DUMMY_LEN_D	3
 23#define GOODIX_BERLIN_SPI_READ_PREFIX_LEN_A	(GOODIX_BERLIN_SPI_TRANS_PREFIX_LEN + \
 24						 GOODIX_BERLIN_REGISTER_WIDTH + \
 25						 GOODIX_BERLIN_SPI_READ_DUMMY_LEN_A)
 26#define GOODIX_BERLIN_SPI_READ_PREFIX_LEN_D	(GOODIX_BERLIN_SPI_TRANS_PREFIX_LEN + \
 27						 GOODIX_BERLIN_REGISTER_WIDTH + \
 28						 GOODIX_BERLIN_SPI_READ_DUMMY_LEN_D)
 29#define GOODIX_BERLIN_SPI_WRITE_PREFIX_LEN	(GOODIX_BERLIN_SPI_TRANS_PREFIX_LEN + \
 30						 GOODIX_BERLIN_REGISTER_WIDTH)
 31
 32#define GOODIX_BERLIN_SPI_WRITE_FLAG		0xF0
 33#define GOODIX_BERLIN_SPI_READ_FLAG		0xF1
 34
 35static int goodix_berlin_spi_read(void *context, const void *reg_buf,
 36				  size_t reg_size, void *val_buf,
 37				  size_t val_size)
 38{
 39	struct spi_device *spi = context;
 40	const struct goodix_berlin_ic_data *ic_data = spi_get_device_match_data(spi);
 41	struct spi_transfer xfers;
 42	struct spi_message spi_msg;
 43	const u32 *reg = reg_buf; /* reg is stored as native u32 at start of buffer */
 44	int error;
 45
 46	if (reg_size != GOODIX_BERLIN_REGISTER_WIDTH)
 47		return -EINVAL;
 48
 49	u8 *buf __free(kfree) =
 50		kzalloc(ic_data->read_prefix_len + val_size, GFP_KERNEL);
 51	if (!buf)
 52		return -ENOMEM;
 53
 54	spi_message_init(&spi_msg);
 55	memset(&xfers, 0, sizeof(xfers));
 56
 57	/* buffer format: 0xF1 + addr(4bytes) + dummy(3/4bytes) + data */
 58	buf[0] = GOODIX_BERLIN_SPI_READ_FLAG;
 59	put_unaligned_be32(*reg, buf + GOODIX_BERLIN_SPI_TRANS_PREFIX_LEN);
 60	memset(buf + GOODIX_BERLIN_SPI_TRANS_PREFIX_LEN + GOODIX_BERLIN_REGISTER_WIDTH,
 61	       0xff, ic_data->read_dummy_len);
 62
 63	xfers.tx_buf = buf;
 64	xfers.rx_buf = buf;
 65	xfers.len = ic_data->read_prefix_len + val_size;
 66	xfers.cs_change = 0;
 67	spi_message_add_tail(&xfers, &spi_msg);
 68
 69	error = spi_sync(spi, &spi_msg);
 70	if (error < 0) {
 71		dev_err(&spi->dev, "spi transfer error, %d", error);
 72		return error;
 73	}
 74
 75	memcpy(val_buf, buf + ic_data->read_prefix_len, val_size);
 76	return error;
 77}
 78
 79static int goodix_berlin_spi_write(void *context, const void *data,
 80				   size_t count)
 81{
 82	unsigned int len = count - GOODIX_BERLIN_REGISTER_WIDTH;
 83	struct spi_device *spi = context;
 84	struct spi_transfer xfers;
 85	struct spi_message spi_msg;
 86	const u32 *reg = data; /* reg is stored as native u32 at start of buffer */
 87	int error;
 88
 89	u8 *buf __free(kfree) =
 90		kzalloc(GOODIX_BERLIN_SPI_WRITE_PREFIX_LEN + len, GFP_KERNEL);
 91	if (!buf)
 92		return -ENOMEM;
 93
 94	spi_message_init(&spi_msg);
 95	memset(&xfers, 0, sizeof(xfers));
 96
 97	buf[0] = GOODIX_BERLIN_SPI_WRITE_FLAG;
 98	put_unaligned_be32(*reg, buf + GOODIX_BERLIN_SPI_TRANS_PREFIX_LEN);
 99	memcpy(buf + GOODIX_BERLIN_SPI_WRITE_PREFIX_LEN,
100	       data + GOODIX_BERLIN_REGISTER_WIDTH, len);
101
102	xfers.tx_buf = buf;
103	xfers.len = GOODIX_BERLIN_SPI_WRITE_PREFIX_LEN + len;
104	xfers.cs_change = 0;
105	spi_message_add_tail(&xfers, &spi_msg);
106
107	error = spi_sync(spi, &spi_msg);
108	if (error < 0) {
109		dev_err(&spi->dev, "spi transfer error, %d", error);
110		return error;
111	}
112
113	return 0;
114}
115
116static const struct regmap_config goodix_berlin_spi_regmap_conf = {
117	.reg_bits = 32,
118	.val_bits = 8,
119	.read = goodix_berlin_spi_read,
120	.write = goodix_berlin_spi_write,
121};
122
123/* vendor & product left unassigned here, should probably be updated from fw info */
124static const struct input_id goodix_berlin_spi_input_id = {
125	.bustype = BUS_SPI,
126};
127
128static int goodix_berlin_spi_probe(struct spi_device *spi)
129{
130	const struct goodix_berlin_ic_data *ic_data = spi_get_device_match_data(spi);
131	struct regmap_config regmap_config;
132	struct regmap *regmap;
133	size_t max_size;
134	int error = 0;
135
136	spi->mode = SPI_MODE_0;
137	spi->bits_per_word = 8;
138	error = spi_setup(spi);
139	if (error)
140		return error;
141
142	max_size = spi_max_transfer_size(spi);
143
144	regmap_config = goodix_berlin_spi_regmap_conf;
145	regmap_config.max_raw_read = max_size - ic_data->read_prefix_len;
146	regmap_config.max_raw_write = max_size - GOODIX_BERLIN_SPI_WRITE_PREFIX_LEN;
147
148	regmap = devm_regmap_init(&spi->dev, NULL, spi, &regmap_config);
149	if (IS_ERR(regmap))
150		return PTR_ERR(regmap);
151
152	error = goodix_berlin_probe(&spi->dev, spi->irq,
153				    &goodix_berlin_spi_input_id, regmap,
154				    ic_data);
155	if (error)
156		return error;
157
158	return 0;
159}
160
161static const struct goodix_berlin_ic_data gt9897_data = {
162	.fw_version_info_addr = GOODIX_BERLIN_FW_VERSION_INFO_ADDR_A,
163	.ic_info_addr = GOODIX_BERLIN_IC_INFO_ADDR_A,
164	.read_dummy_len = GOODIX_BERLIN_SPI_READ_DUMMY_LEN_A,
165	.read_prefix_len = GOODIX_BERLIN_SPI_READ_PREFIX_LEN_A,
166};
167
168static const struct goodix_berlin_ic_data gt9916_data = {
169	.fw_version_info_addr = GOODIX_BERLIN_FW_VERSION_INFO_ADDR_D,
170	.ic_info_addr = GOODIX_BERLIN_IC_INFO_ADDR_D,
171	.read_dummy_len = GOODIX_BERLIN_SPI_READ_DUMMY_LEN_D,
172	.read_prefix_len = GOODIX_BERLIN_SPI_READ_PREFIX_LEN_D,
173};
174
175static const struct spi_device_id goodix_berlin_spi_ids[] = {
176	{ .name = "gt9897", .driver_data = (long)&gt9897_data },
177	{ .name = "gt9916", .driver_data = (long)&gt9916_data },
178	{ },
179};
180MODULE_DEVICE_TABLE(spi, goodix_berlin_spi_ids);
181
182static const struct of_device_id goodix_berlin_spi_of_match[] = {
183	{ .compatible = "goodix,gt9897", .data = &gt9897_data },
184	{ .compatible = "goodix,gt9916", .data = &gt9916_data },
185	{ }
186};
187MODULE_DEVICE_TABLE(of, goodix_berlin_spi_of_match);
188
189static struct spi_driver goodix_berlin_spi_driver = {
190	.driver = {
191		.name = "goodix-berlin-spi",
192		.of_match_table = goodix_berlin_spi_of_match,
193		.pm = pm_sleep_ptr(&goodix_berlin_pm_ops),
194		.dev_groups = goodix_berlin_groups,
195	},
196	.probe = goodix_berlin_spi_probe,
197	.id_table = goodix_berlin_spi_ids,
198};
199module_spi_driver(goodix_berlin_spi_driver);
200
201MODULE_LICENSE("GPL");
202MODULE_DESCRIPTION("Goodix Berlin SPI Touchscreen driver");
203MODULE_AUTHOR("Neil Armstrong <neil.armstrong@linaro.org>");