1 // SPDX-License-Identifier: GPL-2.0+
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.
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.
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.
19 #include <linux/delay.h>
20 #include <linux/i2c.h>
21 #include <linux/module.h>
25 static int max9271_read(struct max9271_device *dev, u8 reg)
29 dev_dbg(&dev->client->dev, "%s(0x%02x)\n", __func__, reg);
31 ret = i2c_smbus_read_byte_data(dev->client, reg);
33 dev_dbg(&dev->client->dev,
34 "%s: register 0x%02x read failed (%d)\n",
40 static int max9271_write(struct max9271_device *dev, u8 reg, u8 val)
44 dev_dbg(&dev->client->dev, "%s(0x%02x, 0x%02x)\n", __func__, reg, val);
46 ret = i2c_smbus_write_byte_data(dev->client, reg, val);
48 dev_err(&dev->client->dev,
49 "%s: register 0x%02x write failed (%d)\n",
56 * max9271_pclk_detect() - Detect valid pixel clock from image sensor
58 * Wait up to 10ms for a valid pixel clock.
60 * Returns 0 for success, < 0 for pixel clock not properly detected
62 static int max9271_pclk_detect(struct max9271_device *dev)
67 for (i = 0; i < 100; i++) {
68 ret = max9271_read(dev, 0x15);
72 if (ret & MAX9271_PCLKDET)
75 usleep_range(50, 100);
78 dev_err(&dev->client->dev, "Unable to detect valid pixel clock\n");
83 int max9271_set_serial_link(struct max9271_device *dev, bool enable)
86 u8 val = MAX9271_REVCCEN | MAX9271_FWDCCEN;
89 ret = max9271_pclk_detect(dev);
95 val |= MAX9271_CLINKEN;
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.
103 * According to the serializer datasheet we should wait 3ms, while
104 * according to the deserializer datasheet we should wait 5ms.
106 * Short delays here appear to show bit-errors in the writes following.
107 * Therefore a conservative delay seems best here.
109 max9271_write(dev, 0x04, val);
110 usleep_range(5000, 8000);
114 EXPORT_SYMBOL_GPL(max9271_set_serial_link);
116 int max9271_configure_i2c(struct max9271_device *dev, u8 i2c_config)
120 ret = max9271_write(dev, 0x0d, i2c_config);
124 /* The delay required after an I2C bus configuration change is not
125 * characterized in the serializer manual. Sleep up to 5msec to
128 usleep_range(3500, 5000);
132 EXPORT_SYMBOL_GPL(max9271_configure_i2c);
134 int max9271_set_high_threshold(struct max9271_device *dev, bool enable)
138 ret = max9271_read(dev, 0x08);
143 * Enable or disable reverse channel high threshold to increase
144 * immunity to power supply noise.
146 max9271_write(dev, 0x08, enable ? ret | BIT(0) : ret & ~BIT(0));
147 usleep_range(2000, 2500);
151 EXPORT_SYMBOL_GPL(max9271_set_high_threshold);
153 int max9271_configure_gmsl_link(struct max9271_device *dev)
156 * Configure the GMSL link:
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
163 * TODO: Make the GMSL link configuration parametric.
165 max9271_write(dev, 0x07, MAX9271_DBL | MAX9271_HVEN |
166 MAX9271_EDC_1BIT_PARITY);
167 usleep_range(5000, 8000);
170 * Adjust spread spectrum to +4% and auto-detect pixel clock
171 * and serial link rate.
173 max9271_write(dev, 0x02, MAX9271_SPREAD_SPECT_4 | MAX9271_R02_RES |
174 MAX9271_PCLK_AUTODETECT | MAX9271_SERIAL_AUTODETECT);
175 usleep_range(5000, 8000);
179 EXPORT_SYMBOL_GPL(max9271_configure_gmsl_link);
181 int max9271_set_gpios(struct max9271_device *dev, u8 gpio_mask)
185 ret = max9271_read(dev, 0x0f);
190 ret = max9271_write(dev, 0x0f, ret);
192 dev_err(&dev->client->dev, "Failed to set gpio (%d)\n", ret);
196 usleep_range(3500, 5000);
200 EXPORT_SYMBOL_GPL(max9271_set_gpios);
202 int max9271_clear_gpios(struct max9271_device *dev, u8 gpio_mask)
206 ret = max9271_read(dev, 0x0f);
211 ret = max9271_write(dev, 0x0f, ret);
213 dev_err(&dev->client->dev, "Failed to clear gpio (%d)\n", ret);
217 usleep_range(3500, 5000);
221 EXPORT_SYMBOL_GPL(max9271_clear_gpios);
223 int max9271_enable_gpios(struct max9271_device *dev, u8 gpio_mask)
227 ret = max9271_read(dev, 0x0e);
231 /* BIT(0) reserved: GPO is always enabled. */
232 ret |= (gpio_mask & ~BIT(0));
233 ret = max9271_write(dev, 0x0e, ret);
235 dev_err(&dev->client->dev, "Failed to enable gpio (%d)\n", ret);
239 usleep_range(3500, 5000);
243 EXPORT_SYMBOL_GPL(max9271_enable_gpios);
245 int max9271_disable_gpios(struct max9271_device *dev, u8 gpio_mask)
249 ret = max9271_read(dev, 0x0e);
253 /* BIT(0) reserved: GPO cannot be disabled */
254 ret &= ~(gpio_mask | BIT(0));
255 ret = max9271_write(dev, 0x0e, ret);
257 dev_err(&dev->client->dev, "Failed to disable gpio (%d)\n", ret);
261 usleep_range(3500, 5000);
265 EXPORT_SYMBOL_GPL(max9271_disable_gpios);
267 int max9271_verify_id(struct max9271_device *dev)
271 ret = max9271_read(dev, 0x1e);
273 dev_err(&dev->client->dev, "MAX9271 ID read failed (%d)\n",
278 if (ret != MAX9271_ID) {
279 dev_err(&dev->client->dev, "MAX9271 ID mismatch (0x%02x)\n",
286 EXPORT_SYMBOL_GPL(max9271_verify_id);
288 int max9271_set_address(struct max9271_device *dev, u8 addr)
292 ret = max9271_write(dev, 0x00, addr << 1);
294 dev_err(&dev->client->dev,
295 "MAX9271 I2C address change failed (%d)\n", ret);
298 usleep_range(3500, 5000);
302 EXPORT_SYMBOL_GPL(max9271_set_address);
304 int max9271_set_deserializer_address(struct max9271_device *dev, u8 addr)
308 ret = max9271_write(dev, 0x01, addr << 1);
310 dev_err(&dev->client->dev,
311 "MAX9271 deserializer address set failed (%d)\n", ret);
314 usleep_range(3500, 5000);
318 EXPORT_SYMBOL_GPL(max9271_set_deserializer_address);
320 int max9271_set_translation(struct max9271_device *dev, u8 source, u8 dest)
324 ret = max9271_write(dev, 0x09, source << 1);
326 dev_err(&dev->client->dev,
327 "MAX9271 I2C translation setup failed (%d)\n", ret);
330 usleep_range(3500, 5000);
332 ret = max9271_write(dev, 0x0a, dest << 1);
334 dev_err(&dev->client->dev,
335 "MAX9271 I2C translation setup failed (%d)\n", ret);
338 usleep_range(3500, 5000);
342 EXPORT_SYMBOL_GPL(max9271_set_translation);
344 MODULE_DESCRIPTION("Maxim MAX9271 GMSL Serializer");
345 MODULE_AUTHOR("Jacopo Mondi");
346 MODULE_LICENSE("GPL v2");