Messages in this thread | | | Subject | Re: [PATCH v2 4/7] media: i2c: max9286: Make channel amplitude programmable | From | Sergei Shtylyov <> | Date | Fri, 16 Oct 2020 11:08:37 +0300 |
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Hello!
On 15.10.2020 21:27, Jacopo Mondi wrote:
> Instrument the function that configures the reverse channel with a > programmable amplitude value. > > This change serves to prepare to adjust the reverse channel amplitude > depending on the remote end high-threshold configuration. > > Signed-off-by: Jacopo Mondi <jacopo+renesas@jmondi.org> > --- > drivers/media/i2c/max9286.c | 22 ++++++++++++++++------ > 1 file changed, 16 insertions(+), 6 deletions(-) > > diff --git a/drivers/media/i2c/max9286.c b/drivers/media/i2c/max9286.c > index 89a7248f5c25..163e102199e3 100644 > --- a/drivers/media/i2c/max9286.c > +++ b/drivers/media/i2c/max9286.c > @@ -906,19 +906,29 @@ static void max9286_v4l2_unregister(struct max9286_priv *priv) > * Probe/Remove > */ > > -static void max9286_reverse_channel_setup(struct max9286_priv *priv) > +static void max9286_reverse_channel_setup(struct max9286_priv *priv, > + unsigned int chan_amplitude) > { > + /* Reverse channel transmission time: default to 1. */ > + u8 chan_config = MAX9286_REV_TRF(1); > + > /* > * Reverse channel setup. > * > * - Enable custom reverse channel configuration (through register 0x3f) > * and set the first pulse length to 35 clock cycles. > - * - Increase the reverse channel amplitude to 170mV to accommodate the > - * high threshold enabled by the serializer driver. > + * - Adjust reverse channel amplitude: values > 130 are programmed > + * using the additional +100mV REV_AMP_X boost flag > */ > max9286_write(priv, 0x3f, MAX9286_EN_REV_CFG | MAX9286_REV_FLEN(35)); > - max9286_write(priv, 0x3b, MAX9286_REV_TRF(1) | MAX9286_REV_AMP(70) | > - MAX9286_REV_AMP_X); > + > + if (chan_amplitude > 100) { > + /* It is not possible express values (100 < x < 130) */
"To express", perhaps?
> + chan_amplitude = chan_amplitude < 130 > + ? 30 : chan_amplitude - 100; > + chan_config |= MAX9286_REV_AMP_X; > + } > + max9286_write(priv, 0x3b, chan_config | MAX9286_REV_AMP(chan_amplitude)); > usleep_range(2000, 2500); > } > [...]
MBR, Sergei
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