1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * Analog Devices AD-FMCOMMS1-EBZ board I2C-SPI bridge driver 4 * 5 * Copyright 2012 Analog Devices Inc. 6 * Author: Lars-Peter Clausen <lars@metafoo.de> 7 */ 8 9 #include <linux/kernel.h> 10 #include <linux/module.h> 11 #include <linux/delay.h> 12 #include <linux/i2c.h> 13 #include <linux/spi/spi.h> 14 #include <asm/unaligned.h> 15 16 #define SPI_XCOMM_SETTINGS_LEN_OFFSET 10 17 #define SPI_XCOMM_SETTINGS_3WIRE BIT(6) 18 #define SPI_XCOMM_SETTINGS_CS_HIGH BIT(5) 19 #define SPI_XCOMM_SETTINGS_SAMPLE_END BIT(4) 20 #define SPI_XCOMM_SETTINGS_CPHA BIT(3) 21 #define SPI_XCOMM_SETTINGS_CPOL BIT(2) 22 #define SPI_XCOMM_SETTINGS_CLOCK_DIV_MASK 0x3 23 #define SPI_XCOMM_SETTINGS_CLOCK_DIV_64 0x2 24 #define SPI_XCOMM_SETTINGS_CLOCK_DIV_16 0x1 25 #define SPI_XCOMM_SETTINGS_CLOCK_DIV_4 0x0 26 27 #define SPI_XCOMM_CMD_UPDATE_CONFIG 0x03 28 #define SPI_XCOMM_CMD_WRITE 0x04 29 30 #define SPI_XCOMM_CLOCK 48000000 31 32 struct spi_xcomm { 33 struct i2c_client *i2c; 34 35 uint16_t settings; 36 uint16_t chipselect; 37 38 unsigned int current_speed; 39 40 uint8_t buf[63]; 41 }; 42 43 static int spi_xcomm_sync_config(struct spi_xcomm *spi_xcomm, unsigned int len) 44 { 45 uint16_t settings; 46 uint8_t *buf = spi_xcomm->buf; 47 48 settings = spi_xcomm->settings; 49 settings |= len << SPI_XCOMM_SETTINGS_LEN_OFFSET; 50 51 buf[0] = SPI_XCOMM_CMD_UPDATE_CONFIG; 52 put_unaligned_be16(settings, &buf[1]); 53 put_unaligned_be16(spi_xcomm->chipselect, &buf[3]); 54 55 return i2c_master_send(spi_xcomm->i2c, buf, 5); 56 } 57 58 static void spi_xcomm_chipselect(struct spi_xcomm *spi_xcomm, 59 struct spi_device *spi, int is_active) 60 { 61 unsigned long cs = spi_get_chipselect(spi, 0); 62 uint16_t chipselect = spi_xcomm->chipselect; 63 64 if (is_active) 65 chipselect |= BIT(cs); 66 else 67 chipselect &= ~BIT(cs); 68 69 spi_xcomm->chipselect = chipselect; 70 } 71 72 static int spi_xcomm_setup_transfer(struct spi_xcomm *spi_xcomm, 73 struct spi_device *spi, struct spi_transfer *t, unsigned int *settings) 74 { 75 if (t->len > 62) 76 return -EINVAL; 77 78 if (t->speed_hz != spi_xcomm->current_speed) { 79 unsigned int divider; 80 81 divider = DIV_ROUND_UP(SPI_XCOMM_CLOCK, t->speed_hz); 82 if (divider >= 64) 83 *settings |= SPI_XCOMM_SETTINGS_CLOCK_DIV_64; 84 else if (divider >= 16) 85 *settings |= SPI_XCOMM_SETTINGS_CLOCK_DIV_16; 86 else 87 *settings |= SPI_XCOMM_SETTINGS_CLOCK_DIV_4; 88 89 spi_xcomm->current_speed = t->speed_hz; 90 } 91 92 if (spi->mode & SPI_CPOL) 93 *settings |= SPI_XCOMM_SETTINGS_CPOL; 94 else 95 *settings &= ~SPI_XCOMM_SETTINGS_CPOL; 96 97 if (spi->mode & SPI_CPHA) 98 *settings &= ~SPI_XCOMM_SETTINGS_CPHA; 99 else 100 *settings |= SPI_XCOMM_SETTINGS_CPHA; 101 102 if (spi->mode & SPI_3WIRE) 103 *settings |= SPI_XCOMM_SETTINGS_3WIRE; 104 else 105 *settings &= ~SPI_XCOMM_SETTINGS_3WIRE; 106 107 return 0; 108 } 109 110 static int spi_xcomm_txrx_bufs(struct spi_xcomm *spi_xcomm, 111 struct spi_device *spi, struct spi_transfer *t) 112 { 113 int ret; 114 115 if (t->tx_buf) { 116 spi_xcomm->buf[0] = SPI_XCOMM_CMD_WRITE; 117 memcpy(spi_xcomm->buf + 1, t->tx_buf, t->len); 118 119 ret = i2c_master_send(spi_xcomm->i2c, spi_xcomm->buf, t->len + 1); 120 if (ret < 0) 121 return ret; 122 else if (ret != t->len + 1) 123 return -EIO; 124 } else if (t->rx_buf) { 125 ret = i2c_master_recv(spi_xcomm->i2c, t->rx_buf, t->len); 126 if (ret < 0) 127 return ret; 128 else if (ret != t->len) 129 return -EIO; 130 } 131 132 return t->len; 133 } 134 135 static int spi_xcomm_transfer_one(struct spi_controller *host, 136 struct spi_message *msg) 137 { 138 struct spi_xcomm *spi_xcomm = spi_controller_get_devdata(host); 139 unsigned int settings = spi_xcomm->settings; 140 struct spi_device *spi = msg->spi; 141 unsigned cs_change = 0; 142 struct spi_transfer *t; 143 bool is_first = true; 144 int status = 0; 145 bool is_last; 146 147 spi_xcomm_chipselect(spi_xcomm, spi, true); 148 149 list_for_each_entry(t, &msg->transfers, transfer_list) { 150 151 if (!t->tx_buf && !t->rx_buf && t->len) { 152 status = -EINVAL; 153 break; 154 } 155 156 status = spi_xcomm_setup_transfer(spi_xcomm, spi, t, &settings); 157 if (status < 0) 158 break; 159 160 is_last = list_is_last(&t->transfer_list, &msg->transfers); 161 cs_change = t->cs_change; 162 163 if (cs_change ^ is_last) 164 settings |= BIT(5); 165 else 166 settings &= ~BIT(5); 167 168 if (t->rx_buf) { 169 spi_xcomm->settings = settings; 170 status = spi_xcomm_sync_config(spi_xcomm, t->len); 171 if (status < 0) 172 break; 173 } else if (settings != spi_xcomm->settings || is_first) { 174 spi_xcomm->settings = settings; 175 status = spi_xcomm_sync_config(spi_xcomm, 0); 176 if (status < 0) 177 break; 178 } 179 180 if (t->len) { 181 status = spi_xcomm_txrx_bufs(spi_xcomm, spi, t); 182 183 if (status < 0) 184 break; 185 186 if (status > 0) 187 msg->actual_length += status; 188 } 189 status = 0; 190 191 spi_transfer_delay_exec(t); 192 193 is_first = false; 194 } 195 196 if (status != 0 || !cs_change) 197 spi_xcomm_chipselect(spi_xcomm, spi, false); 198 199 msg->status = status; 200 spi_finalize_current_message(host); 201 202 return status; 203 } 204 205 static int spi_xcomm_probe(struct i2c_client *i2c) 206 { 207 struct spi_xcomm *spi_xcomm; 208 struct spi_controller *host; 209 int ret; 210 211 host = spi_alloc_host(&i2c->dev, sizeof(*spi_xcomm)); 212 if (!host) 213 return -ENOMEM; 214 215 spi_xcomm = spi_controller_get_devdata(host); 216 spi_xcomm->i2c = i2c; 217 218 host->num_chipselect = 16; 219 host->mode_bits = SPI_CPHA | SPI_CPOL | SPI_3WIRE; 220 host->bits_per_word_mask = SPI_BPW_MASK(8); 221 host->flags = SPI_CONTROLLER_HALF_DUPLEX; 222 host->transfer_one_message = spi_xcomm_transfer_one; 223 host->dev.of_node = i2c->dev.of_node; 224 i2c_set_clientdata(i2c, host); 225 226 ret = devm_spi_register_controller(&i2c->dev, host); 227 if (ret < 0) 228 spi_controller_put(host); 229 230 return ret; 231 } 232 233 static const struct i2c_device_id spi_xcomm_ids[] = { 234 { "spi-xcomm" }, 235 { }, 236 }; 237 MODULE_DEVICE_TABLE(i2c, spi_xcomm_ids); 238 239 static struct i2c_driver spi_xcomm_driver = { 240 .driver = { 241 .name = "spi-xcomm", 242 }, 243 .id_table = spi_xcomm_ids, 244 .probe = spi_xcomm_probe, 245 }; 246 module_i2c_driver(spi_xcomm_driver); 247 248 MODULE_LICENSE("GPL"); 249 MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>"); 250 MODULE_DESCRIPTION("Analog Devices AD-FMCOMMS1-EBZ board I2C-SPI bridge driver"); 251