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
goodix_berlin_spi_read(void * context,const void * reg_buf,size_t reg_size,void * val_buf,size_t val_size)31 static 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
goodix_berlin_spi_write(void * context,const void * data,size_t count)75 static 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
112 static 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 */
120 static const struct input_id goodix_berlin_spi_input_id = {
121 .bustype = BUS_SPI,
122 };
123
goodix_berlin_spi_probe(struct spi_device * spi)124 static 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, ®map_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
155 static const struct spi_device_id goodix_berlin_spi_ids[] = {
156 { "gt9916" },
157 { },
158 };
159 MODULE_DEVICE_TABLE(spi, goodix_berlin_spi_ids);
160
161 static const struct of_device_id goodix_berlin_spi_of_match[] = {
162 { .compatible = "goodix,gt9916", },
163 { }
164 };
165 MODULE_DEVICE_TABLE(of, goodix_berlin_spi_of_match);
166
167 static 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 };
177 module_spi_driver(goodix_berlin_spi_driver);
178
179 MODULE_LICENSE("GPL");
180 MODULE_DESCRIPTION("Goodix Berlin SPI Touchscreen driver");
181 MODULE_AUTHOR("Neil Armstrong <neil.armstrong@linaro.org>");
182