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/gpio/driver.h> 14 #include <linux/spi/spi.h> 15 #include <asm/unaligned.h> 16 17 #define SPI_XCOMM_SETTINGS_LEN_OFFSET 10 18 #define SPI_XCOMM_SETTINGS_3WIRE BIT(6) 19 #define SPI_XCOMM_SETTINGS_CS_HIGH BIT(5) 20 #define SPI_XCOMM_SETTINGS_SAMPLE_END BIT(4) 21 #define SPI_XCOMM_SETTINGS_CPHA BIT(3) 22 #define SPI_XCOMM_SETTINGS_CPOL BIT(2) 23 #define SPI_XCOMM_SETTINGS_CLOCK_DIV_MASK 0x3 24 #define SPI_XCOMM_SETTINGS_CLOCK_DIV_64 0x2 25 #define SPI_XCOMM_SETTINGS_CLOCK_DIV_16 0x1 26 #define SPI_XCOMM_SETTINGS_CLOCK_DIV_4 0x0 27 28 #define SPI_XCOMM_CMD_UPDATE_CONFIG 0x03 29 #define SPI_XCOMM_CMD_WRITE 0x04 30 #define SPI_XCOMM_CMD_GPIO_SET 0x05 31 32 #define SPI_XCOMM_CLOCK 48000000 33 34 struct spi_xcomm { 35 struct i2c_client *i2c; 36 37 struct gpio_chip gc; 38 39 u16 settings; 40 u16 chipselect; 41 42 unsigned int current_speed; 43 44 u8 buf[63]; 45 }; 46 47 static void spi_xcomm_gpio_set_value(struct gpio_chip *chip, 48 unsigned int offset, int val) 49 { 50 struct spi_xcomm *spi_xcomm = gpiochip_get_data(chip); 51 unsigned char buf[2]; 52 53 buf[0] = SPI_XCOMM_CMD_GPIO_SET; 54 buf[1] = !!val; 55 56 i2c_master_send(spi_xcomm->i2c, buf, 2); 57 } 58 59 static int spi_xcomm_gpio_get_direction(struct gpio_chip *chip, 60 unsigned int offset) 61 { 62 return GPIO_LINE_DIRECTION_OUT; 63 } 64 65 static int spi_xcomm_gpio_add(struct spi_xcomm *spi_xcomm) 66 { 67 struct device *dev = &spi_xcomm->i2c->dev; 68 69 if (!IS_ENABLED(CONFIG_GPIOLIB)) 70 return 0; 71 72 spi_xcomm->gc.get_direction = spi_xcomm_gpio_get_direction; 73 spi_xcomm->gc.set = spi_xcomm_gpio_set_value; 74 spi_xcomm->gc.can_sleep = 1; 75 spi_xcomm->gc.base = -1; 76 spi_xcomm->gc.ngpio = 1; 77 spi_xcomm->gc.label = spi_xcomm->i2c->name; 78 spi_xcomm->gc.owner = THIS_MODULE; 79 80 return devm_gpiochip_add_data(dev, &spi_xcomm->gc, spi_xcomm); 81 } 82 83 static int spi_xcomm_sync_config(struct spi_xcomm *spi_xcomm, unsigned int len) 84 { 85 u16 settings; 86 u8 *buf = spi_xcomm->buf; 87 88 settings = spi_xcomm->settings; 89 settings |= len << SPI_XCOMM_SETTINGS_LEN_OFFSET; 90 91 buf[0] = SPI_XCOMM_CMD_UPDATE_CONFIG; 92 put_unaligned_be16(settings, &buf[1]); 93 put_unaligned_be16(spi_xcomm->chipselect, &buf[3]); 94 95 return i2c_master_send(spi_xcomm->i2c, buf, 5); 96 } 97 98 static void spi_xcomm_chipselect(struct spi_xcomm *spi_xcomm, 99 struct spi_device *spi, int is_active) 100 { 101 unsigned long cs = spi_get_chipselect(spi, 0); 102 u16 chipselect = spi_xcomm->chipselect; 103 104 if (is_active) 105 chipselect |= BIT(cs); 106 else 107 chipselect &= ~BIT(cs); 108 109 spi_xcomm->chipselect = chipselect; 110 } 111 112 static int spi_xcomm_setup_transfer(struct spi_xcomm *spi_xcomm, 113 struct spi_device *spi, struct spi_transfer *t, 114 unsigned int *settings) 115 { 116 if (t->len > 62) 117 return -EINVAL; 118 119 if (t->speed_hz != spi_xcomm->current_speed) { 120 unsigned int divider; 121 122 divider = DIV_ROUND_UP(SPI_XCOMM_CLOCK, t->speed_hz); 123 if (divider >= 64) 124 *settings |= SPI_XCOMM_SETTINGS_CLOCK_DIV_64; 125 else if (divider >= 16) 126 *settings |= SPI_XCOMM_SETTINGS_CLOCK_DIV_16; 127 else 128 *settings |= SPI_XCOMM_SETTINGS_CLOCK_DIV_4; 129 130 spi_xcomm->current_speed = t->speed_hz; 131 } 132 133 if (spi->mode & SPI_CPOL) 134 *settings |= SPI_XCOMM_SETTINGS_CPOL; 135 else 136 *settings &= ~SPI_XCOMM_SETTINGS_CPOL; 137 138 if (spi->mode & SPI_CPHA) 139 *settings &= ~SPI_XCOMM_SETTINGS_CPHA; 140 else 141 *settings |= SPI_XCOMM_SETTINGS_CPHA; 142 143 if (spi->mode & SPI_3WIRE) 144 *settings |= SPI_XCOMM_SETTINGS_3WIRE; 145 else 146 *settings &= ~SPI_XCOMM_SETTINGS_3WIRE; 147 148 return 0; 149 } 150 151 static int spi_xcomm_txrx_bufs(struct spi_xcomm *spi_xcomm, 152 struct spi_device *spi, struct spi_transfer *t) 153 { 154 int ret; 155 156 if (t->tx_buf) { 157 spi_xcomm->buf[0] = SPI_XCOMM_CMD_WRITE; 158 memcpy(spi_xcomm->buf + 1, t->tx_buf, t->len); 159 160 ret = i2c_master_send(spi_xcomm->i2c, spi_xcomm->buf, t->len + 1); 161 if (ret < 0) 162 return ret; 163 if (ret != t->len + 1) 164 return -EIO; 165 } else if (t->rx_buf) { 166 ret = i2c_master_recv(spi_xcomm->i2c, t->rx_buf, t->len); 167 if (ret < 0) 168 return ret; 169 if (ret != t->len) 170 return -EIO; 171 } 172 173 return t->len; 174 } 175 176 static int spi_xcomm_transfer_one(struct spi_controller *host, 177 struct spi_message *msg) 178 { 179 struct spi_xcomm *spi_xcomm = spi_controller_get_devdata(host); 180 unsigned int settings = spi_xcomm->settings; 181 struct spi_device *spi = msg->spi; 182 unsigned int cs_change = 0; 183 struct spi_transfer *t; 184 bool is_first = true; 185 int status = 0; 186 bool is_last; 187 188 spi_xcomm_chipselect(spi_xcomm, spi, true); 189 190 list_for_each_entry(t, &msg->transfers, transfer_list) { 191 if (!t->tx_buf && !t->rx_buf && t->len) { 192 status = -EINVAL; 193 break; 194 } 195 196 status = spi_xcomm_setup_transfer(spi_xcomm, spi, t, &settings); 197 if (status < 0) 198 break; 199 200 is_last = list_is_last(&t->transfer_list, &msg->transfers); 201 cs_change = t->cs_change; 202 203 if (cs_change ^ is_last) 204 settings |= BIT(5); 205 else 206 settings &= ~BIT(5); 207 208 if (t->rx_buf) { 209 spi_xcomm->settings = settings; 210 status = spi_xcomm_sync_config(spi_xcomm, t->len); 211 if (status < 0) 212 break; 213 } else if (settings != spi_xcomm->settings || is_first) { 214 spi_xcomm->settings = settings; 215 status = spi_xcomm_sync_config(spi_xcomm, 0); 216 if (status < 0) 217 break; 218 } 219 220 if (t->len) { 221 status = spi_xcomm_txrx_bufs(spi_xcomm, spi, t); 222 223 if (status < 0) 224 break; 225 226 if (status > 0) 227 msg->actual_length += status; 228 } 229 status = 0; 230 231 spi_transfer_delay_exec(t); 232 233 is_first = false; 234 } 235 236 if (status != 0 || !cs_change) 237 spi_xcomm_chipselect(spi_xcomm, spi, false); 238 239 msg->status = status; 240 spi_finalize_current_message(host); 241 242 return status; 243 } 244 245 static int spi_xcomm_probe(struct i2c_client *i2c) 246 { 247 struct spi_xcomm *spi_xcomm; 248 struct spi_controller *host; 249 int ret; 250 251 host = devm_spi_alloc_host(&i2c->dev, sizeof(*spi_xcomm)); 252 if (!host) 253 return -ENOMEM; 254 255 spi_xcomm = spi_controller_get_devdata(host); 256 spi_xcomm->i2c = i2c; 257 258 host->num_chipselect = 16; 259 host->mode_bits = SPI_CPHA | SPI_CPOL | SPI_3WIRE; 260 host->bits_per_word_mask = SPI_BPW_MASK(8); 261 host->flags = SPI_CONTROLLER_HALF_DUPLEX; 262 host->transfer_one_message = spi_xcomm_transfer_one; 263 host->dev.of_node = i2c->dev.of_node; 264 265 ret = devm_spi_register_controller(&i2c->dev, host); 266 if (ret < 0) 267 return ret; 268 269 return spi_xcomm_gpio_add(spi_xcomm); 270 } 271 272 static const struct i2c_device_id spi_xcomm_ids[] = { 273 { "spi-xcomm" }, 274 { }, 275 }; 276 MODULE_DEVICE_TABLE(i2c, spi_xcomm_ids); 277 278 static struct i2c_driver spi_xcomm_driver = { 279 .driver = { 280 .name = "spi-xcomm", 281 }, 282 .id_table = spi_xcomm_ids, 283 .probe = spi_xcomm_probe, 284 }; 285 module_i2c_driver(spi_xcomm_driver); 286 287 MODULE_LICENSE("GPL"); 288 MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>"); 289 MODULE_DESCRIPTION("Analog Devices AD-FMCOMMS1-EBZ board I2C-SPI bridge driver"); 290