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0297ffa6 SSM |
1 | /* |
2 | * drivers/i2c/busses/i2c-tegra-bpmp.c | |
3 | * | |
4 | * Copyright (c) 2016 NVIDIA Corporation. All rights reserved. | |
5 | * | |
6 | * Author: Shardar Shariff Md <smohammed@nvidia.com> | |
7 | * | |
8 | * This program is free software; you can redistribute it and/or modify it | |
9 | * under the terms and conditions of the GNU General Public License, | |
10 | * version 2, as published by the Free Software Foundation. | |
11 | * | |
12 | * This program is distributed in the hope it will be useful, but WITHOUT | |
13 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
14 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for | |
15 | * more details. | |
16 | * | |
17 | * You should have received a copy of the GNU General Public License | |
18 | * along with this program. If not, see <http://www.gnu.org/licenses/>. | |
19 | */ | |
20 | ||
21 | #include <linux/err.h> | |
22 | #include <linux/i2c.h> | |
23 | #include <linux/init.h> | |
24 | #include <linux/kernel.h> | |
25 | #include <linux/module.h> | |
26 | #include <linux/of_device.h> | |
27 | #include <linux/platform_device.h> | |
28 | #include <linux/pm_runtime.h> | |
29 | ||
30 | #include <soc/tegra/bpmp-abi.h> | |
31 | #include <soc/tegra/bpmp.h> | |
32 | ||
33 | /* | |
34 | * Serialized I2C message header size is 6 bytes and includes address, flags | |
35 | * and length | |
36 | */ | |
37 | #define SERIALI2C_HDR_SIZE 6 | |
38 | ||
39 | struct tegra_bpmp_i2c { | |
40 | struct i2c_adapter adapter; | |
41 | struct device *dev; | |
42 | ||
43 | struct tegra_bpmp *bpmp; | |
44 | unsigned int bus; | |
45 | }; | |
46 | ||
47 | /* | |
48 | * Linux flags are translated to BPMP defined I2C flags that are used in BPMP | |
49 | * firmware I2C driver to avoid any issues in future if Linux I2C flags are | |
50 | * changed. | |
51 | */ | |
52 | static int tegra_bpmp_xlate_flags(u16 flags, u16 *out) | |
53 | { | |
54 | if (flags & I2C_M_TEN) { | |
55 | *out |= SERIALI2C_TEN; | |
56 | flags &= ~I2C_M_TEN; | |
57 | } | |
58 | ||
59 | if (flags & I2C_M_RD) { | |
60 | *out |= SERIALI2C_RD; | |
61 | flags &= ~I2C_M_RD; | |
62 | } | |
63 | ||
64 | if (flags & I2C_M_STOP) { | |
65 | *out |= SERIALI2C_STOP; | |
66 | flags &= ~I2C_M_STOP; | |
67 | } | |
68 | ||
69 | if (flags & I2C_M_NOSTART) { | |
70 | *out |= SERIALI2C_NOSTART; | |
71 | flags &= ~I2C_M_NOSTART; | |
72 | } | |
73 | ||
74 | if (flags & I2C_M_REV_DIR_ADDR) { | |
75 | *out |= SERIALI2C_REV_DIR_ADDR; | |
76 | flags &= ~I2C_M_REV_DIR_ADDR; | |
77 | } | |
78 | ||
79 | if (flags & I2C_M_IGNORE_NAK) { | |
80 | *out |= SERIALI2C_IGNORE_NAK; | |
81 | flags &= ~I2C_M_IGNORE_NAK; | |
82 | } | |
83 | ||
84 | if (flags & I2C_M_NO_RD_ACK) { | |
85 | *out |= SERIALI2C_NO_RD_ACK; | |
86 | flags &= ~I2C_M_NO_RD_ACK; | |
87 | } | |
88 | ||
89 | if (flags & I2C_M_RECV_LEN) { | |
90 | *out |= SERIALI2C_RECV_LEN; | |
91 | flags &= ~I2C_M_RECV_LEN; | |
92 | } | |
93 | ||
94 | return (flags != 0) ? -EINVAL : 0; | |
95 | } | |
96 | ||
97 | /** | |
98 | * The serialized I2C format is simply the following: | |
99 | * [addr little-endian][flags little-endian][len little-endian][data if write] | |
100 | * [addr little-endian][flags little-endian][len little-endian][data if write] | |
101 | * ... | |
102 | * | |
103 | * The flags are translated from Linux kernel representation to seriali2c | |
104 | * representation. Any undefined flag being set causes an error. | |
105 | * | |
106 | * The data is there only for writes. Reads have the data transferred in the | |
107 | * other direction, and thus data is not present. | |
108 | * | |
109 | * See deserialize_i2c documentation for the data format in the other direction. | |
110 | */ | |
111 | static int tegra_bpmp_serialize_i2c_msg(struct tegra_bpmp_i2c *i2c, | |
112 | struct mrq_i2c_request *request, | |
113 | struct i2c_msg *msgs, | |
114 | unsigned int num) | |
115 | { | |
116 | char *buf = request->xfer.data_buf; | |
117 | unsigned int i, j, pos = 0; | |
118 | int err; | |
119 | ||
120 | for (i = 0; i < num; i++) { | |
121 | struct i2c_msg *msg = &msgs[i]; | |
122 | u16 flags = 0; | |
123 | ||
124 | err = tegra_bpmp_xlate_flags(msg->flags, &flags); | |
125 | if (err < 0) | |
126 | return err; | |
127 | ||
128 | buf[pos++] = msg->addr & 0xff; | |
129 | buf[pos++] = (msg->addr & 0xff00) >> 8; | |
130 | buf[pos++] = flags & 0xff; | |
131 | buf[pos++] = (flags & 0xff00) >> 8; | |
132 | buf[pos++] = msg->len & 0xff; | |
133 | buf[pos++] = (msg->len & 0xff00) >> 8; | |
134 | ||
135 | if ((flags & SERIALI2C_RD) == 0) { | |
136 | for (j = 0; j < msg->len; j++) | |
137 | buf[pos++] = msg->buf[j]; | |
138 | } | |
139 | } | |
140 | ||
141 | request->xfer.data_size = pos; | |
142 | ||
143 | return 0; | |
144 | } | |
145 | ||
146 | /** | |
147 | * The data in the BPMP -> CPU direction is composed of sequential blocks for | |
148 | * those messages that have I2C_M_RD. So, for example, if you have: | |
149 | * | |
150 | * - !I2C_M_RD, len == 5, data == a0 01 02 03 04 | |
151 | * - !I2C_M_RD, len == 1, data == a0 | |
152 | * - I2C_M_RD, len == 2, data == [uninitialized buffer 1] | |
153 | * - !I2C_M_RD, len == 1, data == a2 | |
154 | * - I2C_M_RD, len == 2, data == [uninitialized buffer 2] | |
155 | * | |
156 | * ...then the data in the BPMP -> CPU direction would be 4 bytes total, and | |
157 | * would contain 2 bytes that will go to uninitialized buffer 1, and 2 bytes | |
158 | * that will go to uninitialized buffer 2. | |
159 | */ | |
160 | static int tegra_bpmp_i2c_deserialize(struct tegra_bpmp_i2c *i2c, | |
161 | struct mrq_i2c_response *response, | |
162 | struct i2c_msg *msgs, | |
163 | unsigned int num) | |
164 | { | |
165 | size_t size = response->xfer.data_size, len = 0, pos = 0; | |
166 | char *buf = response->xfer.data_buf; | |
167 | unsigned int i; | |
168 | ||
169 | for (i = 0; i < num; i++) | |
170 | if (msgs[i].flags & I2C_M_RD) | |
171 | len += msgs[i].len; | |
172 | ||
173 | if (len != size) | |
174 | return -EINVAL; | |
175 | ||
176 | for (i = 0; i < num; i++) { | |
177 | if (msgs[i].flags & I2C_M_RD) { | |
178 | memcpy(msgs[i].buf, buf + pos, msgs[i].len); | |
179 | pos += msgs[i].len; | |
180 | } | |
181 | } | |
182 | ||
183 | return 0; | |
184 | } | |
185 | ||
186 | static int tegra_bpmp_i2c_msg_len_check(struct i2c_msg *msgs, unsigned int num) | |
187 | { | |
188 | size_t tx_len = 0, rx_len = 0; | |
189 | unsigned int i; | |
190 | ||
191 | for (i = 0; i < num; i++) | |
192 | if (!(msgs[i].flags & I2C_M_RD)) | |
193 | tx_len += SERIALI2C_HDR_SIZE + msgs[i].len; | |
194 | ||
195 | if (tx_len > TEGRA_I2C_IPC_MAX_IN_BUF_SIZE) | |
196 | return -EINVAL; | |
197 | ||
198 | for (i = 0; i < num; i++) | |
199 | if ((msgs[i].flags & I2C_M_RD)) | |
200 | rx_len += msgs[i].len; | |
201 | ||
202 | if (rx_len > TEGRA_I2C_IPC_MAX_OUT_BUF_SIZE) | |
203 | return -EINVAL; | |
204 | ||
205 | return 0; | |
206 | } | |
207 | ||
208 | static int tegra_bpmp_i2c_msg_xfer(struct tegra_bpmp_i2c *i2c, | |
209 | struct mrq_i2c_request *request, | |
08960b02 WS |
210 | struct mrq_i2c_response *response, |
211 | bool atomic) | |
0297ffa6 SSM |
212 | { |
213 | struct tegra_bpmp_message msg; | |
214 | int err; | |
215 | ||
216 | request->cmd = CMD_I2C_XFER; | |
217 | request->xfer.bus_id = i2c->bus; | |
218 | ||
219 | memset(&msg, 0, sizeof(msg)); | |
220 | msg.mrq = MRQ_I2C; | |
221 | msg.tx.data = request; | |
222 | msg.tx.size = sizeof(*request); | |
223 | msg.rx.data = response; | |
224 | msg.rx.size = sizeof(*response); | |
225 | ||
08960b02 | 226 | if (atomic) |
0297ffa6 SSM |
227 | err = tegra_bpmp_transfer_atomic(i2c->bpmp, &msg); |
228 | else | |
229 | err = tegra_bpmp_transfer(i2c->bpmp, &msg); | |
230 | ||
231 | return err; | |
232 | } | |
233 | ||
08960b02 WS |
234 | static int tegra_bpmp_i2c_xfer_common(struct i2c_adapter *adapter, |
235 | struct i2c_msg *msgs, int num, | |
236 | bool atomic) | |
0297ffa6 SSM |
237 | { |
238 | struct tegra_bpmp_i2c *i2c = i2c_get_adapdata(adapter); | |
239 | struct mrq_i2c_response response; | |
240 | struct mrq_i2c_request request; | |
241 | int err; | |
242 | ||
243 | err = tegra_bpmp_i2c_msg_len_check(msgs, num); | |
244 | if (err < 0) { | |
245 | dev_err(i2c->dev, "unsupported message length\n"); | |
246 | return err; | |
247 | } | |
248 | ||
249 | memset(&request, 0, sizeof(request)); | |
250 | memset(&response, 0, sizeof(response)); | |
251 | ||
252 | err = tegra_bpmp_serialize_i2c_msg(i2c, &request, msgs, num); | |
253 | if (err < 0) { | |
254 | dev_err(i2c->dev, "failed to serialize message: %d\n", err); | |
255 | return err; | |
256 | } | |
257 | ||
08960b02 | 258 | err = tegra_bpmp_i2c_msg_xfer(i2c, &request, &response, atomic); |
0297ffa6 SSM |
259 | if (err < 0) { |
260 | dev_err(i2c->dev, "failed to transfer message: %d\n", err); | |
261 | return err; | |
262 | } | |
263 | ||
264 | err = tegra_bpmp_i2c_deserialize(i2c, &response, msgs, num); | |
265 | if (err < 0) { | |
266 | dev_err(i2c->dev, "failed to deserialize message: %d\n", err); | |
267 | return err; | |
268 | } | |
269 | ||
270 | return num; | |
271 | } | |
272 | ||
08960b02 WS |
273 | static int tegra_bpmp_i2c_xfer(struct i2c_adapter *adapter, |
274 | struct i2c_msg *msgs, int num) | |
275 | { | |
276 | return tegra_bpmp_i2c_xfer_common(adapter, msgs, num, false); | |
277 | } | |
278 | ||
279 | static int tegra_bpmp_i2c_xfer_atomic(struct i2c_adapter *adapter, | |
280 | struct i2c_msg *msgs, int num) | |
281 | { | |
282 | return tegra_bpmp_i2c_xfer_common(adapter, msgs, num, true); | |
283 | } | |
284 | ||
0297ffa6 SSM |
285 | static u32 tegra_bpmp_i2c_func(struct i2c_adapter *adapter) |
286 | { | |
287 | return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_10BIT_ADDR | | |
288 | I2C_FUNC_PROTOCOL_MANGLING | I2C_FUNC_NOSTART; | |
289 | } | |
290 | ||
291 | static const struct i2c_algorithm tegra_bpmp_i2c_algo = { | |
292 | .master_xfer = tegra_bpmp_i2c_xfer, | |
08960b02 | 293 | .master_xfer_atomic = tegra_bpmp_i2c_xfer_atomic, |
0297ffa6 SSM |
294 | .functionality = tegra_bpmp_i2c_func, |
295 | }; | |
296 | ||
297 | static int tegra_bpmp_i2c_probe(struct platform_device *pdev) | |
298 | { | |
299 | struct tegra_bpmp_i2c *i2c; | |
300 | u32 value; | |
301 | int err; | |
302 | ||
303 | i2c = devm_kzalloc(&pdev->dev, sizeof(*i2c), GFP_KERNEL); | |
304 | if (!i2c) | |
305 | return -ENOMEM; | |
306 | ||
307 | i2c->dev = &pdev->dev; | |
308 | ||
309 | i2c->bpmp = dev_get_drvdata(pdev->dev.parent); | |
310 | if (!i2c->bpmp) | |
311 | return -ENODEV; | |
312 | ||
313 | err = of_property_read_u32(pdev->dev.of_node, "nvidia,bpmp-bus-id", | |
314 | &value); | |
315 | if (err < 0) | |
316 | return err; | |
317 | ||
318 | i2c->bus = value; | |
319 | ||
320 | i2c_set_adapdata(&i2c->adapter, i2c); | |
321 | i2c->adapter.owner = THIS_MODULE; | |
322 | strlcpy(i2c->adapter.name, "Tegra BPMP I2C adapter", | |
323 | sizeof(i2c->adapter.name)); | |
324 | i2c->adapter.algo = &tegra_bpmp_i2c_algo; | |
325 | i2c->adapter.dev.parent = &pdev->dev; | |
326 | i2c->adapter.dev.of_node = pdev->dev.of_node; | |
327 | ||
328 | platform_set_drvdata(pdev, i2c); | |
329 | ||
330 | return i2c_add_adapter(&i2c->adapter); | |
331 | } | |
332 | ||
333 | static int tegra_bpmp_i2c_remove(struct platform_device *pdev) | |
334 | { | |
335 | struct tegra_bpmp_i2c *i2c = platform_get_drvdata(pdev); | |
336 | ||
337 | i2c_del_adapter(&i2c->adapter); | |
338 | ||
339 | return 0; | |
340 | } | |
341 | ||
342 | static const struct of_device_id tegra_bpmp_i2c_of_match[] = { | |
343 | { .compatible = "nvidia,tegra186-bpmp-i2c", }, | |
344 | { } | |
345 | }; | |
346 | MODULE_DEVICE_TABLE(of, tegra_bpmp_i2c_of_match); | |
347 | ||
348 | static struct platform_driver tegra_bpmp_i2c_driver = { | |
349 | .driver = { | |
350 | .name = "tegra-bpmp-i2c", | |
351 | .of_match_table = tegra_bpmp_i2c_of_match, | |
352 | }, | |
353 | .probe = tegra_bpmp_i2c_probe, | |
354 | .remove = tegra_bpmp_i2c_remove, | |
355 | }; | |
356 | module_platform_driver(tegra_bpmp_i2c_driver); | |
357 | ||
8c91fd5e | 358 | MODULE_DESCRIPTION("NVIDIA Tegra BPMP I2C bus controller driver"); |
0297ffa6 SSM |
359 | MODULE_AUTHOR("Shardar Shariff Md <smohammed@nvidia.com>"); |
360 | MODULE_AUTHOR("Juha-Matti Tilli"); | |
361 | MODULE_LICENSE("GPL v2"); |