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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Intel La Jolla Cove Adapter USB-SPI driver
4 *
5 * Copyright (c) 2023, Intel Corporation.
6 */
7
8#include <linux/auxiliary_bus.h>
9#include <linux/bitfield.h>
10#include <linux/bits.h>
11#include <linux/dev_printk.h>
12#include <linux/module.h>
13#include <linux/spi/spi.h>
14#include <linux/usb/ljca.h>
15
16#define LJCA_SPI_BUS_MAX_HZ 48000000
17
18#define LJCA_SPI_BUF_SIZE 60u
19#define LJCA_SPI_MAX_XFER_SIZE \
20 (LJCA_SPI_BUF_SIZE - sizeof(struct ljca_spi_xfer_packet))
21
22#define LJCA_SPI_CLK_MODE_POLARITY BIT(0)
23#define LJCA_SPI_CLK_MODE_PHASE BIT(1)
24
25#define LJCA_SPI_XFER_INDICATOR_ID GENMASK(5, 0)
26#define LJCA_SPI_XFER_INDICATOR_CMPL BIT(6)
27#define LJCA_SPI_XFER_INDICATOR_INDEX BIT(7)
28
29/* SPI commands */
30enum ljca_spi_cmd {
31 LJCA_SPI_INIT = 1,
32 LJCA_SPI_READ,
33 LJCA_SPI_WRITE,
34 LJCA_SPI_WRITEREAD,
35 LJCA_SPI_DEINIT,
36};
37
38enum {
39 LJCA_SPI_BUS_SPEED_24M,
40 LJCA_SPI_BUS_SPEED_12M,
41 LJCA_SPI_BUS_SPEED_8M,
42 LJCA_SPI_BUS_SPEED_6M,
43 LJCA_SPI_BUS_SPEED_4_8M, /*4.8MHz*/
44 LJCA_SPI_BUS_SPEED_MIN = LJCA_SPI_BUS_SPEED_4_8M,
45};
46
47enum {
48 LJCA_SPI_CLOCK_LOW_POLARITY,
49 LJCA_SPI_CLOCK_HIGH_POLARITY,
50};
51
52enum {
53 LJCA_SPI_CLOCK_FIRST_PHASE,
54 LJCA_SPI_CLOCK_SECOND_PHASE,
55};
56
57struct ljca_spi_init_packet {
58 u8 index;
59 u8 speed;
60 u8 mode;
61} __packed;
62
63struct ljca_spi_xfer_packet {
64 u8 indicator;
65 u8 len;
66 u8 data[] __counted_by(len);
67} __packed;
68
69struct ljca_spi_dev {
70 struct ljca_client *ljca;
71 struct spi_controller *controller;
72 struct ljca_spi_info *spi_info;
73 u8 speed;
74 u8 mode;
75
76 u8 obuf[LJCA_SPI_BUF_SIZE];
77 u8 ibuf[LJCA_SPI_BUF_SIZE];
78};
79
80static int ljca_spi_read_write(struct ljca_spi_dev *ljca_spi, const u8 *w_data,
81 u8 *r_data, int len, int id, int complete,
82 int cmd)
83{
84 struct ljca_spi_xfer_packet *w_packet =
85 (struct ljca_spi_xfer_packet *)ljca_spi->obuf;
86 struct ljca_spi_xfer_packet *r_packet =
87 (struct ljca_spi_xfer_packet *)ljca_spi->ibuf;
88 int ret;
89
90 w_packet->indicator = FIELD_PREP(LJCA_SPI_XFER_INDICATOR_ID, id) |
91 FIELD_PREP(LJCA_SPI_XFER_INDICATOR_CMPL, complete) |
92 FIELD_PREP(LJCA_SPI_XFER_INDICATOR_INDEX,
93 ljca_spi->spi_info->id);
94
95 if (cmd == LJCA_SPI_READ) {
96 w_packet->len = sizeof(u16);
97 *(__le16 *)&w_packet->data[0] = cpu_to_le16(len);
98 } else {
99 w_packet->len = len;
100 memcpy(w_packet->data, w_data, len);
101 }
102
103 ret = ljca_transfer(ljca_spi->ljca, cmd, (u8 *)w_packet,
104 struct_size(w_packet, data, w_packet->len),
105 (u8 *)r_packet, LJCA_SPI_BUF_SIZE);
106 if (ret < 0)
107 return ret;
108 else if (ret < sizeof(*r_packet) || r_packet->len <= 0)
109 return -EIO;
110
111 if (r_data)
112 memcpy(r_data, r_packet->data, r_packet->len);
113
114 return 0;
115}
116
117static int ljca_spi_init(struct ljca_spi_dev *ljca_spi, u8 div, u8 mode)
118{
119 struct ljca_spi_init_packet w_packet = {};
120 int ret;
121
122 if (ljca_spi->mode == mode && ljca_spi->speed == div)
123 return 0;
124
125 w_packet.index = ljca_spi->spi_info->id;
126 w_packet.speed = div;
127 w_packet.mode = FIELD_PREP(LJCA_SPI_CLK_MODE_POLARITY,
128 (mode & SPI_CPOL) ? LJCA_SPI_CLOCK_HIGH_POLARITY :
129 LJCA_SPI_CLOCK_LOW_POLARITY) |
130 FIELD_PREP(LJCA_SPI_CLK_MODE_PHASE,
131 (mode & SPI_CPHA) ? LJCA_SPI_CLOCK_SECOND_PHASE :
132 LJCA_SPI_CLOCK_FIRST_PHASE);
133
134 ret = ljca_transfer(ljca_spi->ljca, LJCA_SPI_INIT, (u8 *)&w_packet,
135 sizeof(w_packet), NULL, 0);
136 if (ret < 0)
137 return ret;
138
139 ljca_spi->mode = mode;
140 ljca_spi->speed = div;
141
142 return 0;
143}
144
145static int ljca_spi_deinit(struct ljca_spi_dev *ljca_spi)
146{
147 struct ljca_spi_init_packet w_packet = {};
148 int ret;
149
150 w_packet.index = ljca_spi->spi_info->id;
151
152 ret = ljca_transfer(ljca_spi->ljca, LJCA_SPI_DEINIT, (u8 *)&w_packet,
153 sizeof(w_packet), NULL, 0);
154
155 return ret < 0 ? ret : 0;
156}
157
158static inline int ljca_spi_transfer(struct ljca_spi_dev *ljca_spi,
159 const u8 *tx_data, u8 *rx_data, u16 len)
160{
161 int complete, cur_len;
162 int remaining = len;
163 int cmd, ret, i;
164 int offset = 0;
165
166 if (tx_data && rx_data)
167 cmd = LJCA_SPI_WRITEREAD;
168 else if (tx_data)
169 cmd = LJCA_SPI_WRITE;
170 else if (rx_data)
171 cmd = LJCA_SPI_READ;
172 else
173 return -EINVAL;
174
175 for (i = 0; remaining > 0; i++) {
176 cur_len = min_t(unsigned int, remaining, LJCA_SPI_MAX_XFER_SIZE);
177 complete = (cur_len == remaining);
178
179 ret = ljca_spi_read_write(ljca_spi,
180 tx_data ? tx_data + offset : NULL,
181 rx_data ? rx_data + offset : NULL,
182 cur_len, i, complete, cmd);
183 if (ret)
184 return ret;
185
186 offset += cur_len;
187 remaining -= cur_len;
188 }
189
190 return 0;
191}
192
193static int ljca_spi_transfer_one(struct spi_controller *controller,
194 struct spi_device *spi,
195 struct spi_transfer *xfer)
196{
197 u8 div = DIV_ROUND_UP(controller->max_speed_hz, xfer->speed_hz) / 2 - 1;
198 struct ljca_spi_dev *ljca_spi = spi_controller_get_devdata(controller);
199 int ret;
200
201 div = min_t(u8, LJCA_SPI_BUS_SPEED_MIN, div);
202
203 ret = ljca_spi_init(ljca_spi, div, spi->mode);
204 if (ret) {
205 dev_err(&ljca_spi->ljca->auxdev.dev,
206 "cannot initialize transfer ret %d\n", ret);
207 return ret;
208 }
209
210 ret = ljca_spi_transfer(ljca_spi, xfer->tx_buf, xfer->rx_buf, xfer->len);
211 if (ret)
212 dev_err(&ljca_spi->ljca->auxdev.dev,
213 "transfer failed len: %d\n", xfer->len);
214
215 return ret;
216}
217
218static int ljca_spi_probe(struct auxiliary_device *auxdev,
219 const struct auxiliary_device_id *aux_dev_id)
220{
221 struct ljca_client *ljca = auxiliary_dev_to_ljca_client(auxdev);
222 struct spi_controller *controller;
223 struct ljca_spi_dev *ljca_spi;
224 int ret;
225
226 controller = devm_spi_alloc_host(&auxdev->dev, sizeof(*ljca_spi));
227 if (!controller)
228 return -ENOMEM;
229
230 ljca_spi = spi_controller_get_devdata(controller);
231 ljca_spi->ljca = ljca;
232 ljca_spi->spi_info = dev_get_platdata(&auxdev->dev);
233 ljca_spi->controller = controller;
234
235 controller->bus_num = -1;
236 controller->mode_bits = SPI_CPHA | SPI_CPOL;
237 controller->transfer_one = ljca_spi_transfer_one;
238 controller->auto_runtime_pm = false;
239 controller->max_speed_hz = LJCA_SPI_BUS_MAX_HZ;
240
241 auxiliary_set_drvdata(auxdev, controller);
242
243 ret = spi_register_controller(controller);
244 if (ret)
245 dev_err(&auxdev->dev, "Failed to register controller\n");
246
247 return ret;
248}
249
250static void ljca_spi_dev_remove(struct auxiliary_device *auxdev)
251{
252 struct spi_controller *controller = auxiliary_get_drvdata(auxdev);
253 struct ljca_spi_dev *ljca_spi = spi_controller_get_devdata(controller);
254
255 spi_unregister_controller(controller);
256 ljca_spi_deinit(ljca_spi);
257}
258
259static int ljca_spi_dev_suspend(struct device *dev)
260{
261 struct spi_controller *controller = dev_get_drvdata(dev);
262
263 return spi_controller_suspend(controller);
264}
265
266static int ljca_spi_dev_resume(struct device *dev)
267{
268 struct spi_controller *controller = dev_get_drvdata(dev);
269
270 return spi_controller_resume(controller);
271}
272
273static const struct dev_pm_ops ljca_spi_pm = {
274 SYSTEM_SLEEP_PM_OPS(ljca_spi_dev_suspend, ljca_spi_dev_resume)
275};
276
277static const struct auxiliary_device_id ljca_spi_id_table[] = {
278 { "usb_ljca.ljca-spi", 0 },
279 { /* sentinel */ }
280};
281MODULE_DEVICE_TABLE(auxiliary, ljca_spi_id_table);
282
283static struct auxiliary_driver ljca_spi_driver = {
284 .driver.pm = &ljca_spi_pm,
285 .probe = ljca_spi_probe,
286 .remove = ljca_spi_dev_remove,
287 .id_table = ljca_spi_id_table,
288};
289module_auxiliary_driver(ljca_spi_driver);
290
291MODULE_AUTHOR("Wentong Wu");
292MODULE_AUTHOR("Zhifeng Wang <[email protected]>");
293MODULE_AUTHOR("Lixu Zhang <[email protected]>");
294MODULE_DESCRIPTION("Intel La Jolla Cove Adapter USB-SPI driver");
295MODULE_LICENSE("GPL");
296MODULE_IMPORT_NS("LJCA");