1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
|
// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Analog Devices AD-FMCOMMS1-EBZ board I2C-SPI bridge driver
*
* Copyright 2012 Analog Devices Inc.
* Author: Lars-Peter Clausen <lars@metafoo.de>
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/delay.h>
#include <linux/i2c.h>
#include <linux/gpio/driver.h>
#include <linux/spi/spi.h>
#include <asm/unaligned.h>
#define SPI_XCOMM_SETTINGS_LEN_OFFSET 10
#define SPI_XCOMM_SETTINGS_3WIRE BIT(6)
#define SPI_XCOMM_SETTINGS_CS_HIGH BIT(5)
#define SPI_XCOMM_SETTINGS_SAMPLE_END BIT(4)
#define SPI_XCOMM_SETTINGS_CPHA BIT(3)
#define SPI_XCOMM_SETTINGS_CPOL BIT(2)
#define SPI_XCOMM_SETTINGS_CLOCK_DIV_MASK 0x3
#define SPI_XCOMM_SETTINGS_CLOCK_DIV_64 0x2
#define SPI_XCOMM_SETTINGS_CLOCK_DIV_16 0x1
#define SPI_XCOMM_SETTINGS_CLOCK_DIV_4 0x0
#define SPI_XCOMM_CMD_UPDATE_CONFIG 0x03
#define SPI_XCOMM_CMD_WRITE 0x04
#define SPI_XCOMM_CMD_GPIO_SET 0x05
#define SPI_XCOMM_CLOCK 48000000
struct spi_xcomm {
struct i2c_client *i2c;
struct gpio_chip gc;
u16 settings;
u16 chipselect;
unsigned int current_speed;
u8 buf[63];
};
static void spi_xcomm_gpio_set_value(struct gpio_chip *chip,
unsigned int offset, int val)
{
struct spi_xcomm *spi_xcomm = gpiochip_get_data(chip);
unsigned char buf[2];
buf[0] = SPI_XCOMM_CMD_GPIO_SET;
buf[1] = !!val;
i2c_master_send(spi_xcomm->i2c, buf, 2);
}
static int spi_xcomm_gpio_get_direction(struct gpio_chip *chip,
unsigned int offset)
{
return GPIO_LINE_DIRECTION_OUT;
}
static int spi_xcomm_gpio_add(struct spi_xcomm *spi_xcomm)
{
struct device *dev = &spi_xcomm->i2c->dev;
if (!IS_ENABLED(CONFIG_GPIOLIB))
return 0;
spi_xcomm->gc.get_direction = spi_xcomm_gpio_get_direction;
spi_xcomm->gc.set = spi_xcomm_gpio_set_value;
spi_xcomm->gc.can_sleep = 1;
spi_xcomm->gc.base = -1;
spi_xcomm->gc.ngpio = 1;
spi_xcomm->gc.label = spi_xcomm->i2c->name;
spi_xcomm->gc.owner = THIS_MODULE;
return devm_gpiochip_add_data(dev, &spi_xcomm->gc, spi_xcomm);
}
static int spi_xcomm_sync_config(struct spi_xcomm *spi_xcomm, unsigned int len)
{
u16 settings;
u8 *buf = spi_xcomm->buf;
settings = spi_xcomm->settings;
settings |= len << SPI_XCOMM_SETTINGS_LEN_OFFSET;
buf[0] = SPI_XCOMM_CMD_UPDATE_CONFIG;
put_unaligned_be16(settings, &buf[1]);
put_unaligned_be16(spi_xcomm->chipselect, &buf[3]);
return i2c_master_send(spi_xcomm->i2c, buf, 5);
}
static void spi_xcomm_chipselect(struct spi_xcomm *spi_xcomm,
struct spi_device *spi, int is_active)
{
unsigned long cs = spi_get_chipselect(spi, 0);
u16 chipselect = spi_xcomm->chipselect;
if (is_active)
chipselect |= BIT(cs);
else
chipselect &= ~BIT(cs);
spi_xcomm->chipselect = chipselect;
}
static int spi_xcomm_setup_transfer(struct spi_xcomm *spi_xcomm,
struct spi_device *spi, struct spi_transfer *t,
unsigned int *settings)
{
if (t->len > 62)
return -EINVAL;
if (t->speed_hz != spi_xcomm->current_speed) {
unsigned int divider;
divider = DIV_ROUND_UP(SPI_XCOMM_CLOCK, t->speed_hz);
if (divider >= 64)
*settings |= SPI_XCOMM_SETTINGS_CLOCK_DIV_64;
else if (divider >= 16)
*settings |= SPI_XCOMM_SETTINGS_CLOCK_DIV_16;
else
*settings |= SPI_XCOMM_SETTINGS_CLOCK_DIV_4;
spi_xcomm->current_speed = t->speed_hz;
}
if (spi->mode & SPI_CPOL)
*settings |= SPI_XCOMM_SETTINGS_CPOL;
else
*settings &= ~SPI_XCOMM_SETTINGS_CPOL;
if (spi->mode & SPI_CPHA)
*settings &= ~SPI_XCOMM_SETTINGS_CPHA;
else
*settings |= SPI_XCOMM_SETTINGS_CPHA;
if (spi->mode & SPI_3WIRE)
*settings |= SPI_XCOMM_SETTINGS_3WIRE;
else
*settings &= ~SPI_XCOMM_SETTINGS_3WIRE;
return 0;
}
static int spi_xcomm_txrx_bufs(struct spi_xcomm *spi_xcomm,
struct spi_device *spi, struct spi_transfer *t)
{
int ret;
if (t->tx_buf) {
spi_xcomm->buf[0] = SPI_XCOMM_CMD_WRITE;
memcpy(spi_xcomm->buf + 1, t->tx_buf, t->len);
ret = i2c_master_send(spi_xcomm->i2c, spi_xcomm->buf, t->len + 1);
if (ret < 0)
return ret;
if (ret != t->len + 1)
return -EIO;
} else if (t->rx_buf) {
ret = i2c_master_recv(spi_xcomm->i2c, t->rx_buf, t->len);
if (ret < 0)
return ret;
if (ret != t->len)
return -EIO;
}
return t->len;
}
static int spi_xcomm_transfer_one(struct spi_controller *host,
struct spi_message *msg)
{
struct spi_xcomm *spi_xcomm = spi_controller_get_devdata(host);
unsigned int settings = spi_xcomm->settings;
struct spi_device *spi = msg->spi;
unsigned int cs_change = 0;
struct spi_transfer *t;
bool is_first = true;
int status = 0;
bool is_last;
spi_xcomm_chipselect(spi_xcomm, spi, true);
list_for_each_entry(t, &msg->transfers, transfer_list) {
if (!t->tx_buf && !t->rx_buf && t->len) {
status = -EINVAL;
break;
}
status = spi_xcomm_setup_transfer(spi_xcomm, spi, t, &settings);
if (status < 0)
break;
is_last = list_is_last(&t->transfer_list, &msg->transfers);
cs_change = t->cs_change;
if (cs_change ^ is_last)
settings |= BIT(5);
else
settings &= ~BIT(5);
if (t->rx_buf) {
spi_xcomm->settings = settings;
status = spi_xcomm_sync_config(spi_xcomm, t->len);
if (status < 0)
break;
} else if (settings != spi_xcomm->settings || is_first) {
spi_xcomm->settings = settings;
status = spi_xcomm_sync_config(spi_xcomm, 0);
if (status < 0)
break;
}
if (t->len) {
status = spi_xcomm_txrx_bufs(spi_xcomm, spi, t);
if (status < 0)
break;
if (status > 0)
msg->actual_length += status;
}
status = 0;
spi_transfer_delay_exec(t);
is_first = false;
}
if (status != 0 || !cs_change)
spi_xcomm_chipselect(spi_xcomm, spi, false);
msg->status = status;
spi_finalize_current_message(host);
return status;
}
static int spi_xcomm_probe(struct i2c_client *i2c)
{
struct spi_xcomm *spi_xcomm;
struct spi_controller *host;
int ret;
host = devm_spi_alloc_host(&i2c->dev, sizeof(*spi_xcomm));
if (!host)
return -ENOMEM;
spi_xcomm = spi_controller_get_devdata(host);
spi_xcomm->i2c = i2c;
host->num_chipselect = 16;
host->mode_bits = SPI_CPHA | SPI_CPOL | SPI_3WIRE;
host->bits_per_word_mask = SPI_BPW_MASK(8);
host->flags = SPI_CONTROLLER_HALF_DUPLEX;
host->transfer_one_message = spi_xcomm_transfer_one;
host->dev.of_node = i2c->dev.of_node;
ret = devm_spi_register_controller(&i2c->dev, host);
if (ret < 0)
return ret;
return spi_xcomm_gpio_add(spi_xcomm);
}
static const struct i2c_device_id spi_xcomm_ids[] = {
{ "spi-xcomm" },
{ },
};
MODULE_DEVICE_TABLE(i2c, spi_xcomm_ids);
static struct i2c_driver spi_xcomm_driver = {
.driver = {
.name = "spi-xcomm",
},
.id_table = spi_xcomm_ids,
.probe = spi_xcomm_probe,
};
module_i2c_driver(spi_xcomm_driver);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
MODULE_DESCRIPTION("Analog Devices AD-FMCOMMS1-EBZ board I2C-SPI bridge driver");
|
