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 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 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 }; 123 124 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