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10#include <linux/kernel.h>
11#include <linux/module.h>
12#include <linux/delay.h>
13#include <linux/i2c.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
31#define SPI_XCOMM_CLOCK 48000000
32
33struct spi_xcomm {
34 struct i2c_client *i2c;
35
36 uint16_t settings;
37 uint16_t chipselect;
38
39 unsigned int current_speed;
40
41 uint8_t buf[63];
42};
43
44static int spi_xcomm_sync_config(struct spi_xcomm *spi_xcomm, unsigned int len)
45{
46 uint16_t settings;
47 uint8_t *buf = spi_xcomm->buf;
48
49 settings = spi_xcomm->settings;
50 settings |= len << SPI_XCOMM_SETTINGS_LEN_OFFSET;
51
52 buf[0] = SPI_XCOMM_CMD_UPDATE_CONFIG;
53 put_unaligned_be16(settings, &buf[1]);
54 put_unaligned_be16(spi_xcomm->chipselect, &buf[3]);
55
56 return i2c_master_send(spi_xcomm->i2c, buf, 5);
57}
58
59static void spi_xcomm_chipselect(struct spi_xcomm *spi_xcomm,
60 struct spi_device *spi, int is_active)
61{
62 unsigned long cs = spi->chip_select;
63 uint16_t chipselect = spi_xcomm->chipselect;
64
65 if (is_active)
66 chipselect |= BIT(cs);
67 else
68 chipselect &= ~BIT(cs);
69
70 spi_xcomm->chipselect = chipselect;
71}
72
73static int spi_xcomm_setup_transfer(struct spi_xcomm *spi_xcomm,
74 struct spi_device *spi, struct spi_transfer *t, unsigned int *settings)
75{
76 if (t->len > 62)
77 return -EINVAL;
78
79 if (t->speed_hz != spi_xcomm->current_speed) {
80 unsigned int divider;
81
82 divider = DIV_ROUND_UP(SPI_XCOMM_CLOCK, t->speed_hz);
83 if (divider >= 64)
84 *settings |= SPI_XCOMM_SETTINGS_CLOCK_DIV_64;
85 else if (divider >= 16)
86 *settings |= SPI_XCOMM_SETTINGS_CLOCK_DIV_16;
87 else
88 *settings |= SPI_XCOMM_SETTINGS_CLOCK_DIV_4;
89
90 spi_xcomm->current_speed = t->speed_hz;
91 }
92
93 if (spi->mode & SPI_CPOL)
94 *settings |= SPI_XCOMM_SETTINGS_CPOL;
95 else
96 *settings &= ~SPI_XCOMM_SETTINGS_CPOL;
97
98 if (spi->mode & SPI_CPHA)
99 *settings &= ~SPI_XCOMM_SETTINGS_CPHA;
100 else
101 *settings |= SPI_XCOMM_SETTINGS_CPHA;
102
103 if (spi->mode & SPI_3WIRE)
104 *settings |= SPI_XCOMM_SETTINGS_3WIRE;
105 else
106 *settings &= ~SPI_XCOMM_SETTINGS_3WIRE;
107
108 return 0;
109}
110
111static int spi_xcomm_txrx_bufs(struct spi_xcomm *spi_xcomm,
112 struct spi_device *spi, struct spi_transfer *t)
113{
114 int ret;
115
116 if (t->tx_buf) {
117 spi_xcomm->buf[0] = SPI_XCOMM_CMD_WRITE;
118 memcpy(spi_xcomm->buf + 1, t->tx_buf, t->len);
119
120 ret = i2c_master_send(spi_xcomm->i2c, spi_xcomm->buf, t->len + 1);
121 if (ret < 0)
122 return ret;
123 else if (ret != t->len + 1)
124 return -EIO;
125 } else if (t->rx_buf) {
126 ret = i2c_master_recv(spi_xcomm->i2c, t->rx_buf, t->len);
127 if (ret < 0)
128 return ret;
129 else if (ret != t->len)
130 return -EIO;
131 }
132
133 return t->len;
134}
135
136static int spi_xcomm_transfer_one(struct spi_master *master,
137 struct spi_message *msg)
138{
139 struct spi_xcomm *spi_xcomm = spi_master_get_devdata(master);
140 unsigned int settings = spi_xcomm->settings;
141 struct spi_device *spi = msg->spi;
142 unsigned cs_change = 0;
143 struct spi_transfer *t;
144 bool is_first = true;
145 int status = 0;
146 bool is_last;
147
148 spi_xcomm_chipselect(spi_xcomm, spi, true);
149
150 list_for_each_entry(t, &msg->transfers, transfer_list) {
151
152 if (!t->tx_buf && !t->rx_buf && t->len) {
153 status = -EINVAL;
154 break;
155 }
156
157 status = spi_xcomm_setup_transfer(spi_xcomm, spi, t, &settings);
158 if (status < 0)
159 break;
160
161 is_last = list_is_last(&t->transfer_list, &msg->transfers);
162 cs_change = t->cs_change;
163
164 if (cs_change ^ is_last)
165 settings |= BIT(5);
166 else
167 settings &= ~BIT(5);
168
169 if (t->rx_buf) {
170 spi_xcomm->settings = settings;
171 status = spi_xcomm_sync_config(spi_xcomm, t->len);
172 if (status < 0)
173 break;
174 } else if (settings != spi_xcomm->settings || is_first) {
175 spi_xcomm->settings = settings;
176 status = spi_xcomm_sync_config(spi_xcomm, 0);
177 if (status < 0)
178 break;
179 }
180
181 if (t->len) {
182 status = spi_xcomm_txrx_bufs(spi_xcomm, spi, t);
183
184 if (status < 0)
185 break;
186
187 if (status > 0)
188 msg->actual_length += status;
189 }
190 status = 0;
191
192 if (t->delay_usecs)
193 udelay(t->delay_usecs);
194
195 is_first = false;
196 }
197
198 if (status != 0 || !cs_change)
199 spi_xcomm_chipselect(spi_xcomm, spi, false);
200
201 msg->status = status;
202 spi_finalize_current_message(master);
203
204 return status;
205}
206
207static int spi_xcomm_probe(struct i2c_client *i2c,
208 const struct i2c_device_id *id)
209{
210 struct spi_xcomm *spi_xcomm;
211 struct spi_master *master;
212 int ret;
213
214 master = spi_alloc_master(&i2c->dev, sizeof(*spi_xcomm));
215 if (!master)
216 return -ENOMEM;
217
218 spi_xcomm = spi_master_get_devdata(master);
219 spi_xcomm->i2c = i2c;
220
221 master->num_chipselect = 16;
222 master->mode_bits = SPI_CPHA | SPI_CPOL | SPI_3WIRE;
223 master->bits_per_word_mask = SPI_BPW_MASK(8);
224 master->flags = SPI_MASTER_HALF_DUPLEX;
225 master->transfer_one_message = spi_xcomm_transfer_one;
226 master->dev.of_node = i2c->dev.of_node;
227 i2c_set_clientdata(i2c, master);
228
229 ret = devm_spi_register_master(&i2c->dev, master);
230 if (ret < 0)
231 spi_master_put(master);
232
233 return ret;
234}
235
236static const struct i2c_device_id spi_xcomm_ids[] = {
237 { "spi-xcomm" },
238 { },
239};
240MODULE_DEVICE_TABLE(i2c, spi_xcomm_ids);
241
242static struct i2c_driver spi_xcomm_driver = {
243 .driver = {
244 .name = "spi-xcomm",
245 },
246 .id_table = spi_xcomm_ids,
247 .probe = spi_xcomm_probe,
248};
249module_i2c_driver(spi_xcomm_driver);
250
251MODULE_LICENSE("GPL");
252MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
253MODULE_DESCRIPTION("Analog Devices AD-FMCOMMS1-EBZ board I2C-SPI bridge driver");
254
