// SPDX-License-Identifier: GPL-2.0+ /* * Copyright (C) 2017-2020 Jacopo Mondi * Copyright (C) 2017-2020 Kieran Bingham * Copyright (C) 2017-2020 Laurent Pinchart * Copyright (C) 2017-2020 Niklas Söderlund * Copyright (C) 2016 Renesas Electronics Corporation * Copyright (C) 2015 Cogent Embedded, Inc. * * This file exports functions to control the Maxim MAX9271 GMSL serializer * chip. This is not a self-contained driver, as MAX9271 is usually embedded in * camera modules with at least one image sensor and optional additional * components, such as uController units or ISPs/DSPs. * * Drivers for the camera modules (i.e. rdacm20/21) are expected to use * functions exported from this library driver to maximize code re-use. */ #include #include #include #include static int max9271_read(struct max9271_device *dev, u8 reg) { int ret; dev_dbg(&dev->client->dev, "%s(0x%02x)\n", __func__, reg); ret = i2c_smbus_read_byte_data(dev->client, reg); if (ret < 0) dev_dbg(&dev->client->dev, "%s: register 0x%02x read failed (%d)\n", __func__, reg, ret); return ret; } static int max9271_write(struct max9271_device *dev, u8 reg, u8 val) { int ret; dev_dbg(&dev->client->dev, "%s(0x%02x, 0x%02x)\n", __func__, reg, val); ret = i2c_smbus_write_byte_data(dev->client, reg, val); if (ret < 0) dev_err(&dev->client->dev, "%s: register 0x%02x write failed (%d)\n", __func__, reg, ret); return ret; } /* * max9271_pclk_detect() - Detect valid pixel clock from image sensor * * Wait up to 10ms for a valid pixel clock. * * Returns 0 for success, < 0 for pixel clock not properly detected */ static int max9271_pclk_detect(struct max9271_device *dev) { unsigned int i; int ret; for (i = 0; i < 100; i++) { ret = max9271_read(dev, 0x15); if (ret < 0) return ret; if (ret & MAX9271_PCLKDET) return 0; usleep_range(50, 100); } dev_err(&dev->client->dev, "Unable to detect valid pixel clock\n"); return -EIO; } void max9271_wake_up(struct max9271_device *dev) { /* * Use the chip default address as this function has to be called * before any other one. */ dev->client->addr = MAX9271_DEFAULT_ADDR; i2c_smbus_read_byte(dev->client); usleep_range(5000, 8000); } EXPORT_SYMBOL_GPL(max9271_wake_up); int max9271_set_serial_link(struct max9271_device *dev, bool enable) { int ret; u8 val = MAX9271_REVCCEN | MAX9271_FWDCCEN; if (enable) { ret = max9271_pclk_detect(dev); if (ret) return ret; val |= MAX9271_SEREN; } else { val |= MAX9271_CLINKEN; } /* * The serializer temporarily disables the reverse control channel for * 350µs after starting/stopping the forward serial link, but the * deserializer synchronization time isn't clearly documented. * * According to the serializer datasheet we should wait 3ms, while * according to the deserializer datasheet we should wait 5ms. * * Short delays here appear to show bit-errors in the writes following. * Therefore a conservative delay seems best here. */ ret = max9271_write(dev, 0x04, val); if (ret < 0) return ret; usleep_range(5000, 8000); return 0; } EXPORT_SYMBOL_GPL(max9271_set_serial_link); int max9271_configure_i2c(struct max9271_device *dev, u8 i2c_config) { int ret; ret = max9271_write(dev, 0x0d, i2c_config); if (ret < 0) return ret; /* The delay required after an I2C bus configuration change is not * characterized in the serializer manual. Sleep up to 5msec to * stay safe. */ usleep_range(3500, 5000); return 0; } EXPORT_SYMBOL_GPL(max9271_configure_i2c); int max9271_set_high_threshold(struct max9271_device *dev, bool enable) { int ret; ret = max9271_read(dev, 0x08); if (ret < 0) return ret; /* * Enable or disable reverse channel high threshold to increase * immunity to power supply noise. */ ret = max9271_write(dev, 0x08, enable ? ret | BIT(0) : ret & ~BIT(0)); if (ret < 0) return ret; usleep_range(2000, 2500); return 0; } EXPORT_SYMBOL_GPL(max9271_set_high_threshold); int max9271_configure_gmsl_link(struct max9271_device *dev) { int ret; /* * Configure the GMSL link: * * - Double input mode, high data rate, 24-bit mode * - Latch input data on PCLKIN rising edge * - Enable HS/VS encoding * - 1-bit parity error detection * * TODO: Make the GMSL link configuration parametric. */ ret = max9271_write(dev, 0x07, MAX9271_DBL | MAX9271_HVEN | MAX9271_EDC_1BIT_PARITY); if (ret < 0) return ret; usleep_range(5000, 8000); /* * Adjust spread spectrum to +4% and auto-detect pixel clock * and serial link rate. */ ret = max9271_write(dev, 0x02, MAX9271_SPREAD_SPECT_4 | MAX9271_R02_RES | MAX9271_PCLK_AUTODETECT | MAX9271_SERIAL_AUTODETECT); if (ret < 0) return ret; usleep_range(5000, 8000); return 0; } EXPORT_SYMBOL_GPL(max9271_configure_gmsl_link); int max9271_set_gpios(struct max9271_device *dev, u8 gpio_mask) { int ret; ret = max9271_read(dev, 0x0f); if (ret < 0) return 0; ret |= gpio_mask; ret = max9271_write(dev, 0x0f, ret); if (ret < 0) { dev_err(&dev->client->dev, "Failed to set gpio (%d)\n", ret); return ret; } usleep_range(3500, 5000); return 0; } EXPORT_SYMBOL_GPL(max9271_set_gpios); int max9271_clear_gpios(struct max9271_device *dev, u8 gpio_mask) { int ret; ret = max9271_read(dev, 0x0f); if (ret < 0) return 0; ret &= ~gpio_mask; ret = max9271_write(dev, 0x0f, ret); if (ret < 0) { dev_err(&dev->client->dev, "Failed to clear gpio (%d)\n", ret); return ret; } usleep_range(3500, 5000); return 0; } EXPORT_SYMBOL_GPL(max9271_clear_gpios); int max9271_enable_gpios(struct max9271_device *dev, u8 gpio_mask) { int ret; ret = max9271_read(dev, 0x0e); if (ret < 0) return 0; /* BIT(0) reserved: GPO is always enabled. */ ret |= (gpio_mask & ~BIT(0)); ret = max9271_write(dev, 0x0e, ret); if (ret < 0) { dev_err(&dev->client->dev, "Failed to enable gpio (%d)\n", ret); return ret; } usleep_range(3500, 5000); return 0; } EXPORT_SYMBOL_GPL(max9271_enable_gpios); int max9271_disable_gpios(struct max9271_device *dev, u8 gpio_mask) { int ret; ret = max9271_read(dev, 0x0e); if (ret < 0) return 0; /* BIT(0) reserved: GPO cannot be disabled */ ret &= ~(gpio_mask | BIT(0)); ret = max9271_write(dev, 0x0e, ret); if (ret < 0) { dev_err(&dev->client->dev, "Failed to disable gpio (%d)\n", ret); return ret; } usleep_range(3500, 5000); return 0; } EXPORT_SYMBOL_GPL(max9271_disable_gpios); int max9271_verify_id(struct max9271_device *dev) { int ret; ret = max9271_read(dev, 0x1e); if (ret < 0) { dev_err(&dev->client->dev, "MAX9271 ID read failed (%d)\n", ret); return ret; } if (ret != MAX9271_ID) { dev_err(&dev->client->dev, "MAX9271 ID mismatch (0x%02x)\n", ret); return -ENXIO; } return 0; } EXPORT_SYMBOL_GPL(max9271_verify_id); int max9271_set_address(struct max9271_device *dev, u8 addr) { int ret; ret = max9271_write(dev, 0x00, addr << 1); if (ret < 0) { dev_err(&dev->client->dev, "MAX9271 I2C address change failed (%d)\n", ret); return ret; } usleep_range(3500, 5000); return 0; } EXPORT_SYMBOL_GPL(max9271_set_address); int max9271_set_deserializer_address(struct max9271_device *dev, u8 addr) { int ret; ret = max9271_write(dev, 0x01, addr << 1); if (ret < 0) { dev_err(&dev->client->dev, "MAX9271 deserializer address set failed (%d)\n", ret); return ret; } usleep_range(3500, 5000); return 0; } EXPORT_SYMBOL_GPL(max9271_set_deserializer_address); int max9271_set_translation(struct max9271_device *dev, u8 source, u8 dest) { int ret; ret = max9271_write(dev, 0x09, source << 1); if (ret < 0) { dev_err(&dev->client->dev, "MAX9271 I2C translation setup failed (%d)\n", ret); return ret; } usleep_range(3500, 5000); ret = max9271_write(dev, 0x0a, dest << 1); if (ret < 0) { dev_err(&dev->client->dev, "MAX9271 I2C translation setup failed (%d)\n", ret); return ret; } usleep_range(3500, 5000); return 0; } EXPORT_SYMBOL_GPL(max9271_set_translation); MODULE_DESCRIPTION("Maxim MAX9271 GMSL Serializer"); MODULE_AUTHOR("Jacopo Mondi"); MODULE_LICENSE("GPL v2");