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b3165900 LPC |
1 | /* |
2 | * Analog Devices AD-FMCOMMS1-EBZ board I2C-SPI bridge driver | |
3 | * | |
4 | * Copyright 2012 Analog Devices Inc. | |
5 | * Author: Lars-Peter Clausen <lars@metafoo.de> | |
6 | * | |
7 | * Licensed under the GPL-2 or later. | |
8 | */ | |
9 | ||
10 | #include <linux/kernel.h> | |
11 | #include <linux/init.h> | |
12 | #include <linux/module.h> | |
13 | #include <linux/delay.h> | |
14 | #include <linux/i2c.h> | |
15 | #include <linux/spi/spi.h> | |
16 | #include <asm/unaligned.h> | |
17 | ||
18 | #define SPI_XCOMM_SETTINGS_LEN_OFFSET 10 | |
19 | #define SPI_XCOMM_SETTINGS_3WIRE BIT(6) | |
20 | #define SPI_XCOMM_SETTINGS_CS_HIGH BIT(5) | |
21 | #define SPI_XCOMM_SETTINGS_SAMPLE_END BIT(4) | |
22 | #define SPI_XCOMM_SETTINGS_CPHA BIT(3) | |
23 | #define SPI_XCOMM_SETTINGS_CPOL BIT(2) | |
24 | #define SPI_XCOMM_SETTINGS_CLOCK_DIV_MASK 0x3 | |
25 | #define SPI_XCOMM_SETTINGS_CLOCK_DIV_64 0x2 | |
26 | #define SPI_XCOMM_SETTINGS_CLOCK_DIV_16 0x1 | |
27 | #define SPI_XCOMM_SETTINGS_CLOCK_DIV_4 0x0 | |
28 | ||
29 | #define SPI_XCOMM_CMD_UPDATE_CONFIG 0x03 | |
30 | #define SPI_XCOMM_CMD_WRITE 0x04 | |
31 | ||
32 | #define SPI_XCOMM_CLOCK 48000000 | |
33 | ||
34 | struct spi_xcomm { | |
35 | struct i2c_client *i2c; | |
36 | ||
37 | uint16_t settings; | |
38 | uint16_t chipselect; | |
39 | ||
40 | unsigned int current_speed; | |
41 | ||
42 | uint8_t buf[63]; | |
43 | }; | |
44 | ||
45 | static int spi_xcomm_sync_config(struct spi_xcomm *spi_xcomm, unsigned int len) | |
46 | { | |
47 | uint16_t settings; | |
48 | uint8_t *buf = spi_xcomm->buf; | |
49 | ||
50 | settings = spi_xcomm->settings; | |
51 | settings |= len << SPI_XCOMM_SETTINGS_LEN_OFFSET; | |
52 | ||
53 | buf[0] = SPI_XCOMM_CMD_UPDATE_CONFIG; | |
54 | put_unaligned_be16(settings, &buf[1]); | |
55 | put_unaligned_be16(spi_xcomm->chipselect, &buf[3]); | |
56 | ||
57 | return i2c_master_send(spi_xcomm->i2c, buf, 5); | |
58 | } | |
59 | ||
60 | static void spi_xcomm_chipselect(struct spi_xcomm *spi_xcomm, | |
61 | struct spi_device *spi, int is_active) | |
62 | { | |
63 | unsigned long cs = spi->chip_select; | |
64 | uint16_t chipselect = spi_xcomm->chipselect; | |
65 | ||
66 | if (is_active) | |
67 | chipselect |= BIT(cs); | |
68 | else | |
69 | chipselect &= ~BIT(cs); | |
70 | ||
71 | spi_xcomm->chipselect = chipselect; | |
72 | } | |
73 | ||
74 | static int spi_xcomm_setup_transfer(struct spi_xcomm *spi_xcomm, | |
75 | struct spi_device *spi, struct spi_transfer *t, unsigned int *settings) | |
76 | { | |
77 | unsigned int speed; | |
78 | ||
24778be2 | 79 | if (t->len > 62) |
b3165900 LPC |
80 | return -EINVAL; |
81 | ||
82 | speed = t->speed_hz ? t->speed_hz : spi->max_speed_hz; | |
83 | ||
84 | if (speed != spi_xcomm->current_speed) { | |
85 | unsigned int divider = DIV_ROUND_UP(SPI_XCOMM_CLOCK, speed); | |
86 | if (divider >= 64) | |
87 | *settings |= SPI_XCOMM_SETTINGS_CLOCK_DIV_64; | |
88 | else if (divider >= 16) | |
89 | *settings |= SPI_XCOMM_SETTINGS_CLOCK_DIV_16; | |
90 | else | |
91 | *settings |= SPI_XCOMM_SETTINGS_CLOCK_DIV_4; | |
92 | ||
93 | spi_xcomm->current_speed = speed; | |
94 | } | |
95 | ||
96 | if (spi->mode & SPI_CPOL) | |
97 | *settings |= SPI_XCOMM_SETTINGS_CPOL; | |
98 | else | |
99 | *settings &= ~SPI_XCOMM_SETTINGS_CPOL; | |
100 | ||
101 | if (spi->mode & SPI_CPHA) | |
102 | *settings &= ~SPI_XCOMM_SETTINGS_CPHA; | |
103 | else | |
104 | *settings |= SPI_XCOMM_SETTINGS_CPHA; | |
105 | ||
106 | if (spi->mode & SPI_3WIRE) | |
107 | *settings |= SPI_XCOMM_SETTINGS_3WIRE; | |
108 | else | |
109 | *settings &= ~SPI_XCOMM_SETTINGS_3WIRE; | |
110 | ||
111 | return 0; | |
112 | } | |
113 | ||
114 | static int spi_xcomm_txrx_bufs(struct spi_xcomm *spi_xcomm, | |
115 | struct spi_device *spi, struct spi_transfer *t) | |
116 | { | |
117 | int ret; | |
118 | ||
119 | if (t->tx_buf) { | |
120 | spi_xcomm->buf[0] = SPI_XCOMM_CMD_WRITE; | |
121 | memcpy(spi_xcomm->buf + 1, t->tx_buf, t->len); | |
122 | ||
123 | ret = i2c_master_send(spi_xcomm->i2c, spi_xcomm->buf, t->len + 1); | |
124 | if (ret < 0) | |
125 | return ret; | |
126 | else if (ret != t->len + 1) | |
127 | return -EIO; | |
128 | } else if (t->rx_buf) { | |
129 | ret = i2c_master_recv(spi_xcomm->i2c, t->rx_buf, t->len); | |
130 | if (ret < 0) | |
131 | return ret; | |
132 | else if (ret != t->len) | |
133 | return -EIO; | |
134 | } | |
135 | ||
136 | return t->len; | |
137 | } | |
138 | ||
139 | static int spi_xcomm_transfer_one(struct spi_master *master, | |
140 | struct spi_message *msg) | |
141 | { | |
142 | struct spi_xcomm *spi_xcomm = spi_master_get_devdata(master); | |
143 | unsigned int settings = spi_xcomm->settings; | |
144 | struct spi_device *spi = msg->spi; | |
145 | unsigned cs_change = 0; | |
146 | struct spi_transfer *t; | |
147 | bool is_first = true; | |
148 | int status = 0; | |
149 | bool is_last; | |
150 | ||
151 | is_first = true; | |
152 | ||
153 | spi_xcomm_chipselect(spi_xcomm, spi, true); | |
154 | ||
155 | list_for_each_entry(t, &msg->transfers, transfer_list) { | |
156 | ||
157 | if (!t->tx_buf && !t->rx_buf && t->len) { | |
158 | status = -EINVAL; | |
159 | break; | |
160 | } | |
161 | ||
162 | status = spi_xcomm_setup_transfer(spi_xcomm, spi, t, &settings); | |
163 | if (status < 0) | |
164 | break; | |
165 | ||
166 | is_last = list_is_last(&t->transfer_list, &msg->transfers); | |
167 | cs_change = t->cs_change; | |
168 | ||
169 | if (cs_change ^ is_last) | |
170 | settings |= BIT(5); | |
171 | else | |
172 | settings &= ~BIT(5); | |
173 | ||
174 | if (t->rx_buf) { | |
175 | spi_xcomm->settings = settings; | |
176 | status = spi_xcomm_sync_config(spi_xcomm, t->len); | |
177 | if (status < 0) | |
178 | break; | |
179 | } else if (settings != spi_xcomm->settings || is_first) { | |
180 | spi_xcomm->settings = settings; | |
181 | status = spi_xcomm_sync_config(spi_xcomm, 0); | |
182 | if (status < 0) | |
183 | break; | |
184 | } | |
185 | ||
186 | if (t->len) { | |
187 | status = spi_xcomm_txrx_bufs(spi_xcomm, spi, t); | |
188 | ||
189 | if (status < 0) | |
190 | break; | |
191 | ||
192 | if (status > 0) | |
193 | msg->actual_length += status; | |
194 | } | |
195 | status = 0; | |
196 | ||
197 | if (t->delay_usecs) | |
198 | udelay(t->delay_usecs); | |
199 | ||
200 | is_first = false; | |
201 | } | |
202 | ||
203 | if (status != 0 || !cs_change) | |
204 | spi_xcomm_chipselect(spi_xcomm, spi, false); | |
205 | ||
206 | msg->status = status; | |
207 | spi_finalize_current_message(master); | |
208 | ||
209 | return status; | |
210 | } | |
211 | ||
fd4a319b | 212 | static int spi_xcomm_probe(struct i2c_client *i2c, |
b3165900 LPC |
213 | const struct i2c_device_id *id) |
214 | { | |
215 | struct spi_xcomm *spi_xcomm; | |
216 | struct spi_master *master; | |
217 | int ret; | |
218 | ||
219 | master = spi_alloc_master(&i2c->dev, sizeof(*spi_xcomm)); | |
220 | if (!master) | |
221 | return -ENOMEM; | |
222 | ||
223 | spi_xcomm = spi_master_get_devdata(master); | |
224 | spi_xcomm->i2c = i2c; | |
225 | ||
226 | master->num_chipselect = 16; | |
227 | master->mode_bits = SPI_CPHA | SPI_CPOL | SPI_3WIRE; | |
24778be2 | 228 | master->bits_per_word_mask = SPI_BPW_MASK(8); |
b3165900 | 229 | master->flags = SPI_MASTER_HALF_DUPLEX; |
b3165900 LPC |
230 | master->transfer_one_message = spi_xcomm_transfer_one; |
231 | master->dev.of_node = i2c->dev.of_node; | |
232 | i2c_set_clientdata(i2c, master); | |
233 | ||
234 | ret = spi_register_master(master); | |
235 | if (ret < 0) | |
236 | spi_master_put(master); | |
237 | ||
238 | return ret; | |
239 | } | |
240 | ||
fd4a319b | 241 | static int spi_xcomm_remove(struct i2c_client *i2c) |
b3165900 LPC |
242 | { |
243 | struct spi_master *master = i2c_get_clientdata(i2c); | |
244 | ||
245 | spi_unregister_master(master); | |
246 | ||
247 | return 0; | |
248 | } | |
249 | ||
250 | static const struct i2c_device_id spi_xcomm_ids[] = { | |
251 | { "spi-xcomm" }, | |
252 | { }, | |
253 | }; | |
254 | ||
255 | static struct i2c_driver spi_xcomm_driver = { | |
256 | .driver = { | |
257 | .name = "spi-xcomm", | |
258 | .owner = THIS_MODULE, | |
259 | }, | |
260 | .id_table = spi_xcomm_ids, | |
261 | .probe = spi_xcomm_probe, | |
fd4a319b | 262 | .remove = spi_xcomm_remove, |
b3165900 LPC |
263 | }; |
264 | module_i2c_driver(spi_xcomm_driver); | |
265 | ||
266 | MODULE_LICENSE("GPL"); | |
267 | MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>"); | |
268 | MODULE_DESCRIPTION("Analog Devices AD-FMCOMMS1-EBZ board I2C-SPI bridge driver"); |