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linux/drivers/media/i2c/max9271.c
Jacopo Mondi 9e0bf8393d media: i2c: max9271: Introduce wake_up() function 
The MAX9271 chip manual prescribes a delay of 5 milliseconds
after the chip exits from low power state.

Add a new function to the max9271 library driver that wakes up the chip
with a dummy i2c transaction and implements the correct delay of 5
milliseconds after the chip exits from low power state.

Use the newly introduced function in the rdacm20 and rdacm21 camera
drivers. The former was not respecting the required delay while the
latter was waiting for a too-short timeout.

Signed-off-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
Reviewed-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
2021-06-17 11:30:21 +02:00

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// 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 <linux/delay.h>
#include <linux/i2c.h>
#include <linux/module.h>
#include "max9271.h"
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");
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