1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * Copyright (C) 2017-2020 Jacopo Mondi
4 * Copyright (C) 2017-2020 Kieran Bingham
5 * Copyright (C) 2017-2020 Laurent Pinchart
6 * Copyright (C) 2017-2020 Niklas Söderlund
7 * Copyright (C) 2016 Renesas Electronics Corporation
8 * Copyright (C) 2015 Cogent Embedded, Inc.
9 *
10 * This file exports functions to control the Maxim MAX9271 GMSL serializer
11 * chip. This is not a self-contained driver, as MAX9271 is usually embedded in
12 * camera modules with at least one image sensor and optional additional
13 * components, such as uController units or ISPs/DSPs.
14 *
15 * Drivers for the camera modules (i.e. rdacm20/21) are expected to use
16 * functions exported from this library driver to maximize code re-use.
17 */
18
19 #include <linux/delay.h>
20 #include <linux/i2c.h>
21 #include <linux/module.h>
22
23 #include "max9271.h"
24
max9271_read(struct max9271_device * dev,u8 reg)25 static int max9271_read(struct max9271_device *dev, u8 reg)
26 {
27 int ret;
28
29 dev_dbg(&dev->client->dev, "%s(0x%02x)\n", __func__, reg);
30
31 ret = i2c_smbus_read_byte_data(dev->client, reg);
32 if (ret < 0)
33 dev_dbg(&dev->client->dev,
34 "%s: register 0x%02x read failed (%d)\n",
35 __func__, reg, ret);
36
37 return ret;
38 }
39
max9271_write(struct max9271_device * dev,u8 reg,u8 val)40 static int max9271_write(struct max9271_device *dev, u8 reg, u8 val)
41 {
42 int ret;
43
44 dev_dbg(&dev->client->dev, "%s(0x%02x, 0x%02x)\n", __func__, reg, val);
45
46 ret = i2c_smbus_write_byte_data(dev->client, reg, val);
47 if (ret < 0)
48 dev_err(&dev->client->dev,
49 "%s: register 0x%02x write failed (%d)\n",
50 __func__, reg, ret);
51
52 return ret;
53 }
54
55 /*
56 * max9271_pclk_detect() - Detect valid pixel clock from image sensor
57 *
58 * Wait up to 10ms for a valid pixel clock.
59 *
60 * Returns 0 for success, < 0 for pixel clock not properly detected
61 */
max9271_pclk_detect(struct max9271_device * dev)62 static int max9271_pclk_detect(struct max9271_device *dev)
63 {
64 unsigned int i;
65 int ret;
66
67 for (i = 0; i < 100; i++) {
68 ret = max9271_read(dev, 0x15);
69 if (ret < 0)
70 return ret;
71
72 if (ret & MAX9271_PCLKDET)
73 return 0;
74
75 usleep_range(50, 100);
76 }
77
78 dev_err(&dev->client->dev, "Unable to detect valid pixel clock\n");
79
80 return -EIO;
81 }
82
max9271_set_serial_link(struct max9271_device * dev,bool enable)83 int max9271_set_serial_link(struct max9271_device *dev, bool enable)
84 {
85 int ret;
86 u8 val = MAX9271_REVCCEN | MAX9271_FWDCCEN;
87
88 if (enable) {
89 ret = max9271_pclk_detect(dev);
90 if (ret)
91 return ret;
92
93 val |= MAX9271_SEREN;
94 } else {
95 val |= MAX9271_CLINKEN;
96 }
97
98 /*
99 * The serializer temporarily disables the reverse control channel for
100 * 350µs after starting/stopping the forward serial link, but the
101 * deserializer synchronization time isn't clearly documented.
102 *
103 * According to the serializer datasheet we should wait 3ms, while
104 * according to the deserializer datasheet we should wait 5ms.
105 *
106 * Short delays here appear to show bit-errors in the writes following.
107 * Therefore a conservative delay seems best here.
108 */
109 max9271_write(dev, 0x04, val);
110 usleep_range(5000, 8000);
111
112 return 0;
113 }
114 EXPORT_SYMBOL_GPL(max9271_set_serial_link);
115
max9271_configure_i2c(struct max9271_device * dev,u8 i2c_config)116 int max9271_configure_i2c(struct max9271_device *dev, u8 i2c_config)
117 {
118 int ret;
119
120 ret = max9271_write(dev, 0x0d, i2c_config);
121 if (ret)
122 return ret;
123
124 /* The delay required after an I2C bus configuration change is not
125 * characterized in the serializer manual. Sleep up to 5msec to
126 * stay safe.
127 */
128 usleep_range(3500, 5000);
129
130 return 0;
131 }
132 EXPORT_SYMBOL_GPL(max9271_configure_i2c);
133
max9271_set_high_threshold(struct max9271_device * dev,bool enable)134 int max9271_set_high_threshold(struct max9271_device *dev, bool enable)
135 {
136 int ret;
137
138 ret = max9271_read(dev, 0x08);
139 if (ret < 0)
140 return ret;
141
142 /*
143 * Enable or disable reverse channel high threshold to increase
144 * immunity to power supply noise.
145 */
146 max9271_write(dev, 0x08, enable ? ret | BIT(0) : ret & ~BIT(0));
147 usleep_range(2000, 2500);
148
149 return 0;
150 }
151 EXPORT_SYMBOL_GPL(max9271_set_high_threshold);
152
max9271_configure_gmsl_link(struct max9271_device * dev)153 int max9271_configure_gmsl_link(struct max9271_device *dev)
154 {
155 /*
156 * Configure the GMSL link:
157 *
158 * - Double input mode, high data rate, 24-bit mode
159 * - Latch input data on PCLKIN rising edge
160 * - Enable HS/VS encoding
161 * - 1-bit parity error detection
162 *
163 * TODO: Make the GMSL link configuration parametric.
164 */
165 max9271_write(dev, 0x07, MAX9271_DBL | MAX9271_HVEN |
166 MAX9271_EDC_1BIT_PARITY);
167 usleep_range(5000, 8000);
168
169 /*
170 * Adjust spread spectrum to +4% and auto-detect pixel clock
171 * and serial link rate.
172 */
173 max9271_write(dev, 0x02, MAX9271_SPREAD_SPECT_4 | MAX9271_R02_RES |
174 MAX9271_PCLK_AUTODETECT | MAX9271_SERIAL_AUTODETECT);
175 usleep_range(5000, 8000);
176
177 return 0;
178 }
179 EXPORT_SYMBOL_GPL(max9271_configure_gmsl_link);
180
max9271_set_gpios(struct max9271_device * dev,u8 gpio_mask)181 int max9271_set_gpios(struct max9271_device *dev, u8 gpio_mask)
182 {
183 int ret;
184
185 ret = max9271_read(dev, 0x0f);
186 if (ret < 0)
187 return 0;
188
189 ret |= gpio_mask;
190 ret = max9271_write(dev, 0x0f, ret);
191 if (ret < 0) {
192 dev_err(&dev->client->dev, "Failed to set gpio (%d)\n", ret);
193 return ret;
194 }
195
196 usleep_range(3500, 5000);
197
198 return 0;
199 }
200 EXPORT_SYMBOL_GPL(max9271_set_gpios);
201
max9271_clear_gpios(struct max9271_device * dev,u8 gpio_mask)202 int max9271_clear_gpios(struct max9271_device *dev, u8 gpio_mask)
203 {
204 int ret;
205
206 ret = max9271_read(dev, 0x0f);
207 if (ret < 0)
208 return 0;
209
210 ret &= ~gpio_mask;
211 ret = max9271_write(dev, 0x0f, ret);
212 if (ret < 0) {
213 dev_err(&dev->client->dev, "Failed to clear gpio (%d)\n", ret);
214 return ret;
215 }
216
217 usleep_range(3500, 5000);
218
219 return 0;
220 }
221 EXPORT_SYMBOL_GPL(max9271_clear_gpios);
222
max9271_enable_gpios(struct max9271_device * dev,u8 gpio_mask)223 int max9271_enable_gpios(struct max9271_device *dev, u8 gpio_mask)
224 {
225 int ret;
226
227 ret = max9271_read(dev, 0x0e);
228 if (ret < 0)
229 return 0;
230
231 /* BIT(0) reserved: GPO is always enabled. */
232 ret |= (gpio_mask & ~BIT(0));
233 ret = max9271_write(dev, 0x0e, ret);
234 if (ret < 0) {
235 dev_err(&dev->client->dev, "Failed to enable gpio (%d)\n", ret);
236 return ret;
237 }
238
239 usleep_range(3500, 5000);
240
241 return 0;
242 }
243 EXPORT_SYMBOL_GPL(max9271_enable_gpios);
244
max9271_disable_gpios(struct max9271_device * dev,u8 gpio_mask)245 int max9271_disable_gpios(struct max9271_device *dev, u8 gpio_mask)
246 {
247 int ret;
248
249 ret = max9271_read(dev, 0x0e);
250 if (ret < 0)
251 return 0;
252
253 /* BIT(0) reserved: GPO cannot be disabled */
254 ret &= ~(gpio_mask | BIT(0));
255 ret = max9271_write(dev, 0x0e, ret);
256 if (ret < 0) {
257 dev_err(&dev->client->dev, "Failed to disable gpio (%d)\n", ret);
258 return ret;
259 }
260
261 usleep_range(3500, 5000);
262
263 return 0;
264 }
265 EXPORT_SYMBOL_GPL(max9271_disable_gpios);
266
max9271_verify_id(struct max9271_device * dev)267 int max9271_verify_id(struct max9271_device *dev)
268 {
269 int ret;
270
271 ret = max9271_read(dev, 0x1e);
272 if (ret < 0) {
273 dev_err(&dev->client->dev, "MAX9271 ID read failed (%d)\n",
274 ret);
275 return ret;
276 }
277
278 if (ret != MAX9271_ID) {
279 dev_err(&dev->client->dev, "MAX9271 ID mismatch (0x%02x)\n",
280 ret);
281 return -ENXIO;
282 }
283
284 return 0;
285 }
286 EXPORT_SYMBOL_GPL(max9271_verify_id);
287
max9271_set_address(struct max9271_device * dev,u8 addr)288 int max9271_set_address(struct max9271_device *dev, u8 addr)
289 {
290 int ret;
291
292 ret = max9271_write(dev, 0x00, addr << 1);
293 if (ret < 0) {
294 dev_err(&dev->client->dev,
295 "MAX9271 I2C address change failed (%d)\n", ret);
296 return ret;
297 }
298 usleep_range(3500, 5000);
299
300 return 0;
301 }
302 EXPORT_SYMBOL_GPL(max9271_set_address);
303
max9271_set_deserializer_address(struct max9271_device * dev,u8 addr)304 int max9271_set_deserializer_address(struct max9271_device *dev, u8 addr)
305 {
306 int ret;
307
308 ret = max9271_write(dev, 0x01, addr << 1);
309 if (ret < 0) {
310 dev_err(&dev->client->dev,
311 "MAX9271 deserializer address set failed (%d)\n", ret);
312 return ret;
313 }
314 usleep_range(3500, 5000);
315
316 return 0;
317 }
318 EXPORT_SYMBOL_GPL(max9271_set_deserializer_address);
319
max9271_set_translation(struct max9271_device * dev,u8 source,u8 dest)320 int max9271_set_translation(struct max9271_device *dev, u8 source, u8 dest)
321 {
322 int ret;
323
324 ret = max9271_write(dev, 0x09, source << 1);
325 if (ret < 0) {
326 dev_err(&dev->client->dev,
327 "MAX9271 I2C translation setup failed (%d)\n", ret);
328 return ret;
329 }
330 usleep_range(3500, 5000);
331
332 ret = max9271_write(dev, 0x0a, dest << 1);
333 if (ret < 0) {
334 dev_err(&dev->client->dev,
335 "MAX9271 I2C translation setup failed (%d)\n", ret);
336 return ret;
337 }
338 usleep_range(3500, 5000);
339
340 return 0;
341 }
342 EXPORT_SYMBOL_GPL(max9271_set_translation);
343
344 MODULE_DESCRIPTION("Maxim MAX9271 GMSL Serializer");
345 MODULE_AUTHOR("Jacopo Mondi");
346 MODULE_LICENSE("GPL v2");
347