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/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 | |
32 | struct 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 | |
43 | static 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(val: settings, p: &buf[1]); |
53 | put_unaligned_be16(val: spi_xcomm->chipselect, p: &buf[3]); |
54 | |
55 | return i2c_master_send(client: spi_xcomm->i2c, buf, count: 5); |
56 | } |
57 | |
58 | static void spi_xcomm_chipselect(struct spi_xcomm *spi_xcomm, |
59 | struct spi_device *spi, int is_active) |
60 | { |
61 | unsigned long cs = spi_get_chipselect(spi, idx: 0); |
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 | |
72 | static 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 | |
110 | static 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(client: spi_xcomm->i2c, buf: spi_xcomm->buf, count: 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(client: spi_xcomm->i2c, buf: t->rx_buf, count: 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 | |
135 | static int spi_xcomm_transfer_one(struct spi_controller *host, |
136 | struct spi_message *msg) |
137 | { |
138 | struct spi_xcomm *spi_xcomm = spi_controller_get_devdata(ctlr: host); |
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, is_active: 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: &settings); |
157 | if (status < 0) |
158 | break; |
159 | |
160 | is_last = list_is_last(list: &t->transfer_list, head: &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, len: 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, len: 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, is_active: false); |
198 | |
199 | msg->status = status; |
200 | spi_finalize_current_message(ctlr: host); |
201 | |
202 | return status; |
203 | } |
204 | |
205 | static int spi_xcomm_probe(struct i2c_client *i2c) |
206 | { |
207 | struct spi_xcomm *spi_xcomm; |
208 | struct spi_controller *host; |
209 | int ret; |
210 | |
211 | host = spi_alloc_host(dev: &i2c->dev, size: sizeof(*spi_xcomm)); |
212 | if (!host) |
213 | return -ENOMEM; |
214 | |
215 | spi_xcomm = spi_controller_get_devdata(ctlr: host); |
216 | spi_xcomm->i2c = i2c; |
217 | |
218 | host->num_chipselect = 16; |
219 | host->mode_bits = SPI_CPHA | SPI_CPOL | SPI_3WIRE; |
220 | host->bits_per_word_mask = SPI_BPW_MASK(8); |
221 | host->flags = SPI_CONTROLLER_HALF_DUPLEX; |
222 | host->transfer_one_message = spi_xcomm_transfer_one; |
223 | host->dev.of_node = i2c->dev.of_node; |
224 | i2c_set_clientdata(client: i2c, data: host); |
225 | |
226 | ret = devm_spi_register_controller(dev: &i2c->dev, ctlr: host); |
227 | if (ret < 0) |
228 | spi_controller_put(ctlr: host); |
229 | |
230 | return ret; |
231 | } |
232 | |
233 | static const struct i2c_device_id spi_xcomm_ids[] = { |
234 | { "spi-xcomm" }, |
235 | { }, |
236 | }; |
237 | MODULE_DEVICE_TABLE(i2c, spi_xcomm_ids); |
238 | |
239 | static struct i2c_driver spi_xcomm_driver = { |
240 | .driver = { |
241 | .name = "spi-xcomm" , |
242 | }, |
243 | .id_table = spi_xcomm_ids, |
244 | .probe = spi_xcomm_probe, |
245 | }; |
246 | module_i2c_driver(spi_xcomm_driver); |
247 | |
248 | MODULE_LICENSE("GPL" ); |
249 | MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>" ); |
250 | MODULE_DESCRIPTION("Analog Devices AD-FMCOMMS1-EBZ board I2C-SPI bridge driver" ); |
251 | |