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media: i2c: max9271: Introduce wake_up() function

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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>
This commit is contained in:
Jacopo Mondi 2021-06-16 14:46:08 +02:00 committed by Mauro Carvalho Chehab
parent ad01032aaf
commit 9e0bf8393d
4 changed files with 23 additions and 7 deletions
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12
drivers/media/i2c/max9271.c
View File

@ -80,6 +80,18 @@ static int max9271_pclk_detect(struct max9271_device *dev)
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;

9
drivers/media/i2c/max9271.h
View File

@ -85,6 +85,15 @@ struct max9271_device {
struct i2c_client *client;
};
/**
* max9271_wake_up() - Wake up the serializer by issuing an i2c transaction
* @dev: The max9271 device
*
* This function shall be called before any other interaction with the
* serializer.
*/
void max9271_wake_up(struct max9271_device *dev);
/**
* max9271_set_serial_link() - Enable/disable serial link
* @dev: The max9271 device

4
drivers/media/i2c/rdacm20.c
View File

@ -455,9 +455,7 @@ static int rdacm20_initialize(struct rdacm20_device *dev)
unsigned int retry = 3;
int ret;
/* Verify communication with the MAX9271: ping to wakeup. */
dev->serializer->client->addr = MAX9271_DEFAULT_ADDR;
i2c_smbus_read_byte(dev->serializer->client);
max9271_wake_up(dev->serializer);
/* Serial link disabled during config as it needs a valid pixel clock. */
ret = max9271_set_serial_link(dev->serializer, false);

5
drivers/media/i2c/rdacm21.c
View File

@ -450,10 +450,7 @@ static int rdacm21_initialize(struct rdacm21_device *dev)
{
int ret;
/* Verify communication with the MAX9271: ping to wakeup. */
dev->serializer.client->addr = MAX9271_DEFAULT_ADDR;
i2c_smbus_read_byte(dev->serializer.client);
usleep_range(3000, 5000);
max9271_wake_up(&dev->serializer);
/* Enable reverse channel and disable the serial link. */
ret = max9271_set_serial_link(&dev->serializer, false);