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 <linux/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
spi_xcomm_gpio_set_value(struct gpio_chip * chip,unsigned int offset,int val)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
spi_xcomm_gpio_get_direction(struct gpio_chip * chip,unsigned int offset)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
spi_xcomm_gpio_add(struct spi_xcomm * spi_xcomm)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
spi_xcomm_sync_config(struct spi_xcomm * spi_xcomm,unsigned int len)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
spi_xcomm_chipselect(struct spi_xcomm * spi_xcomm,struct spi_device * spi,int is_active)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
spi_xcomm_setup_transfer(struct spi_xcomm * spi_xcomm,struct spi_device * spi,struct spi_transfer * t,unsigned int * settings)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
spi_xcomm_txrx_bufs(struct spi_xcomm * spi_xcomm,struct spi_device * spi,struct spi_transfer * t)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
spi_xcomm_transfer_one(struct spi_controller * host,struct spi_message * msg)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
spi_xcomm_probe(struct i2c_client * i2c)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