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SubjectRe: [PATCH 07/16] media: i2c: rdacm2x: Fix wake up delay
Hi Jacopo,

Thank you for the patch.

On Wed, Feb 17, 2021 at 01:33:01PM +0000, Kieran Bingham wrote:
> On 16/02/2021 17:41, Jacopo Mondi wrote:
> > The MAX9271 chip manual prescribes a delay of 5 milliseconds
> > after the chip exists from low power state.
> >
> > Adjust the required delay in the rdacm21 camera module and add it
> > to the rdacm20 that currently doesn't implement one.
>
> This sounds to me like it should be a common function in the max9271 module:
>
> > /* Verify communication with the MAX9271: ping to wakeup. */
> > dev->serializer.client->addr = MAX9271_DEFAULT_ADDR;
> > i2c_smbus_read_byte(dev->serializer.client);
> > usleep_range(5000, 8000);
>
> Especially as that MAX9271_DEFAULT_ADDR should probably be handled
> directly in the max9271.c file too, and the RDACM's shouldn't care about it.

I think this is a good idea. With this addressed,

Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

> If we end up moving the max9271 'library' into more of a module/device
> then this would have to be done in it's 'probe' anyway, so it's likely
> better handled down there...?
>
> But ... it's not essential at this point in the series, so if you want
> to keep this patch as is,
>
> Reviewed-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
> > Signed-off-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
> > ---
> > drivers/media/i2c/rdacm20.c | 1 +
> > drivers/media/i2c/rdacm21.c | 2 +-
> > 2 files changed, 2 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/media/i2c/rdacm20.c b/drivers/media/i2c/rdacm20.c
> > index ea30cc936531..39e4b4241870 100644
> > --- a/drivers/media/i2c/rdacm20.c
> > +++ b/drivers/media/i2c/rdacm20.c
> > @@ -460,6 +460,7 @@ static int rdacm20_initialize(struct rdacm20_device *dev)
> > /* Verify communication with the MAX9271: ping to wakeup. */
> > dev->serializer.client->addr = MAX9271_DEFAULT_ADDR;
> > i2c_smbus_read_byte(dev->serializer.client);
> > + usleep_range(5000, 8000);
> >
> > /* Serial link disabled during config as it needs a valid pixel clock. */
> > ret = max9271_set_serial_link(&dev->serializer, false);
> > diff --git a/drivers/media/i2c/rdacm21.c b/drivers/media/i2c/rdacm21.c
> > index 179d107f494c..b22a2ca5340b 100644
> > --- a/drivers/media/i2c/rdacm21.c
> > +++ b/drivers/media/i2c/rdacm21.c
> > @@ -453,7 +453,7 @@ static int rdacm21_initialize(struct rdacm21_device *dev)
> > /* 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);
> > + usleep_range(5000, 8000);
> >
> > /* Enable reverse channel and disable the serial link. */
> > ret = max9271_set_serial_link(&dev->serializer, false);

--
Regards,

Laurent Pinchart

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