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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
32struct 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
43static 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
58static void spi_xcomm_chipselect(struct spi_xcomm *spi_xcomm,
59 struct spi_device *spi, int is_active)
60{
61 unsigned long cs = spi->chip_select;
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
72static 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
110static 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
135static int spi_xcomm_transfer_one(struct spi_master *master,
136 struct spi_message *msg)
137{
138 struct spi_xcomm *spi_xcomm = spi_master_get_devdata(master);
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(master);
201
202 return status;
203}
204
205static int spi_xcomm_probe(struct i2c_client *i2c,
206 const struct i2c_device_id *id)
207{
208 struct spi_xcomm *spi_xcomm;
209 struct spi_master *master;
210 int ret;
211
212 master = spi_alloc_master(&i2c->dev, sizeof(*spi_xcomm));
213 if (!master)
214 return -ENOMEM;
215
216 spi_xcomm = spi_master_get_devdata(master);
217 spi_xcomm->i2c = i2c;
218
219 master->num_chipselect = 16;
220 master->mode_bits = SPI_CPHA | SPI_CPOL | SPI_3WIRE;
221 master->bits_per_word_mask = SPI_BPW_MASK(8);
222 master->flags = SPI_MASTER_HALF_DUPLEX;
223 master->transfer_one_message = spi_xcomm_transfer_one;
224 master->dev.of_node = i2c->dev.of_node;
225 i2c_set_clientdata(i2c, master);
226
227 ret = devm_spi_register_master(&i2c->dev, master);
228 if (ret < 0)
229 spi_master_put(master);
230
231 return ret;
232}
233
234static const struct i2c_device_id spi_xcomm_ids[] = {
235 { "spi-xcomm" },
236 { },
237};
238MODULE_DEVICE_TABLE(i2c, spi_xcomm_ids);
239
240static struct i2c_driver spi_xcomm_driver = {
241 .driver = {
242 .name = "spi-xcomm",
243 },
244 .id_table = spi_xcomm_ids,
245 .probe = spi_xcomm_probe,
246};
247module_i2c_driver(spi_xcomm_driver);
248
249MODULE_LICENSE("GPL");
250MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
251MODULE_DESCRIPTION("Analog Devices AD-FMCOMMS1-EBZ board I2C-SPI bridge driver");
252
