[3/5] media: i2c: max9286: Parse overlap window value
diff mbox series

Message ID 20200316202757.529740-4-jacopo+renesas@jmondi.org
State New
Delegated to: Kieran Bingham
Headers show
Series
  • media: i2c: max9286: Add configuration properties
Related show

Commit Message

Jacopo Mondi March 16, 2020, 8:27 p.m. UTC
Parse the 'maxim,overlap-window' property value and cache its
content to later program registers 0x63 and 0x64.

As specified by the bindings documentation, the property is mandatory as
long as a default value cannot be established to guarantee DTB backward
compatibility.

Signed-off-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
---
 drivers/media/i2c/max9286.c | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)

Comments

Kieran Bingham March 18, 2020, 9:50 a.m. UTC | #1
Hi Jacopo,

On 16/03/2020 20:27, Jacopo Mondi wrote:
> Parse the 'maxim,overlap-window' property value and cache its
> content to later program registers 0x63 and 0x64.
> 
> As specified by the bindings documentation, the property is mandatory as
> long as a default value cannot be established to guarantee DTB backward
> compatibility.

Well, we don't yet have the DTB bindings 'in' I don't believe so I don't
think we need to worry about backwards compatibility yet...

Oh, or do you mean in the future it wouldn't have to be mandatory
perhaps ...

> 
> Signed-off-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
> ---
>  drivers/media/i2c/max9286.c | 26 ++++++++++++++++++++++++++
>  1 file changed, 26 insertions(+)
> 
> diff --git a/drivers/media/i2c/max9286.c b/drivers/media/i2c/max9286.c
> index 06edd8bd3e82..0357515860b2 100644
> --- a/drivers/media/i2c/max9286.c
> +++ b/drivers/media/i2c/max9286.c
> @@ -117,6 +117,9 @@
>  #define MAX9286_REV_FLEN(n)		((n) - 20)
>  /* Register 0x49 */
>  #define MAX9286_VIDEO_DETECT_MASK	0x0f
> +/* Register 0x64 */
> +#define MAX9286_OVLP_WINDOWH_MASK	GENMASK(4, 0)
> +
>  /* Register 0x69 */
>  #define MAX9286_LFLTBMONMASKED		BIT(7)
>  #define MAX9286_LOCKMONMASKED		BIT(6)
> @@ -164,6 +167,8 @@ struct max9286_priv {
>  	unsigned int csi2_data_lanes;
>  	struct max9286_source sources[MAX9286_NUM_GMSL];
>  	struct v4l2_async_notifier notifier;
> +
> +	u32 overlap_window;
>  };
>  
>  static struct max9286_source *next_source(struct max9286_priv *priv,
> @@ -895,6 +900,11 @@ static int max9286_setup(struct max9286_priv *priv)
>  	max9286_write(priv, 0x01, MAX9286_FSYNCMODE_INT_HIZ |
>  		      MAX9286_FSYNCMETH_AUTO);
>  
> +	/* Configure overlap window. */
> +	max9286_write(priv, 0x63, priv->overlap_window);
> +	max9286_write(priv, 0x64, (priv->overlap_window >> 8) &
> +				  MAX9286_OVLP_WINDOWH_MASK);
> +
>  	/* Enable HS/VS encoding, use D14/15 for HS/VS, invert VS. */
>  	max9286_write(priv, 0x0c, MAX9286_HVEN | MAX9286_INVVS |
>  		      MAX9286_HVSRC_D14);
> @@ -1041,8 +1051,24 @@ static int max9286_parse_dt(struct max9286_priv *priv)
>  	struct device_node *i2c_mux;
>  	struct device_node *node = NULL;
>  	unsigned int i2c_mux_mask = 0;
> +	int ret;
>  
>  	of_node_get(dev->of_node);
> +
> +	/*
> +	 * FIXM: Require overlap window value to be specified by DTS as long as

/FIXM/FIXME/

> +	 * the control function is not clarified. As soon as a default
> +	 * behaviour can be established drop this requirement, while older

/established/established,/
/requirement,/requirement/


> +	 * DTBs are guaranteed to be fully specified.
> +	 */
> +	ret = of_property_read_u32(dev->of_node, "maxim,overlap-window",
> +				   &priv->overlap_window);
> +	if (ret) {
> +		dev_err(dev, "Missing property \"maxim,overlap-window\"\n");
> +		of_node_put(dev->of_node);
> +		return -EINVAL;
> +	}
> +

Other wise, this looks fine except for my concerns and wondering if this
could be approached by defining a property of the requirements in the
serializer and parsing that in some form.


--
Kieran

>  	i2c_mux = of_find_node_by_name(dev->of_node, "i2c-mux");
>  	if (!i2c_mux) {
>  		dev_err(dev, "Failed to find i2c-mux node\n");
>
Jacopo Mondi March 18, 2020, 2:22 p.m. UTC | #2
Hi Kieran,

On Wed, Mar 18, 2020 at 09:50:22AM +0000, Kieran Bingham wrote:
> Hi Jacopo,
>
> On 16/03/2020 20:27, Jacopo Mondi wrote:
> > Parse the 'maxim,overlap-window' property value and cache its
> > content to later program registers 0x63 and 0x64.
> >
> > As specified by the bindings documentation, the property is mandatory as
> > long as a default value cannot be established to guarantee DTB backward
> > compatibility.
>
> Well, we don't yet have the DTB bindings 'in' I don't believe so I don't
> think we need to worry about backwards compatibility yet...
>
> Oh, or do you mean in the future it wouldn't have to be mandatory
> perhaps ...

I meant in future. As we don't know now what an opportune default is
for this un-documented setting, I think having all DTBs using this
first version fully specified will make any decision we take in future
easier to implement in a back-ward compatible way.

>
> >
> > Signed-off-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
> > ---
> >  drivers/media/i2c/max9286.c | 26 ++++++++++++++++++++++++++
> >  1 file changed, 26 insertions(+)
> >
> > diff --git a/drivers/media/i2c/max9286.c b/drivers/media/i2c/max9286.c
> > index 06edd8bd3e82..0357515860b2 100644
> > --- a/drivers/media/i2c/max9286.c
> > +++ b/drivers/media/i2c/max9286.c
> > @@ -117,6 +117,9 @@
> >  #define MAX9286_REV_FLEN(n)		((n) - 20)
> >  /* Register 0x49 */
> >  #define MAX9286_VIDEO_DETECT_MASK	0x0f
> > +/* Register 0x64 */
> > +#define MAX9286_OVLP_WINDOWH_MASK	GENMASK(4, 0)
> > +
> >  /* Register 0x69 */
> >  #define MAX9286_LFLTBMONMASKED		BIT(7)
> >  #define MAX9286_LOCKMONMASKED		BIT(6)
> > @@ -164,6 +167,8 @@ struct max9286_priv {
> >  	unsigned int csi2_data_lanes;
> >  	struct max9286_source sources[MAX9286_NUM_GMSL];
> >  	struct v4l2_async_notifier notifier;
> > +
> > +	u32 overlap_window;
> >  };
> >
> >  static struct max9286_source *next_source(struct max9286_priv *priv,
> > @@ -895,6 +900,11 @@ static int max9286_setup(struct max9286_priv *priv)
> >  	max9286_write(priv, 0x01, MAX9286_FSYNCMODE_INT_HIZ |
> >  		      MAX9286_FSYNCMETH_AUTO);
> >
> > +	/* Configure overlap window. */
> > +	max9286_write(priv, 0x63, priv->overlap_window);
> > +	max9286_write(priv, 0x64, (priv->overlap_window >> 8) &
> > +				  MAX9286_OVLP_WINDOWH_MASK);
> > +
> >  	/* Enable HS/VS encoding, use D14/15 for HS/VS, invert VS. */
> >  	max9286_write(priv, 0x0c, MAX9286_HVEN | MAX9286_INVVS |
> >  		      MAX9286_HVSRC_D14);
> > @@ -1041,8 +1051,24 @@ static int max9286_parse_dt(struct max9286_priv *priv)
> >  	struct device_node *i2c_mux;
> >  	struct device_node *node = NULL;
> >  	unsigned int i2c_mux_mask = 0;
> > +	int ret;
> >
> >  	of_node_get(dev->of_node);
> > +
> > +	/*
> > +	 * FIXM: Require overlap window value to be specified by DTS as long as
>
> /FIXM/FIXME/
>
> > +	 * the control function is not clarified. As soon as a default
> > +	 * behaviour can be established drop this requirement, while older
>
> /established/established,/
> /requirement,/requirement/
>
>
> > +	 * DTBs are guaranteed to be fully specified.
> > +	 */
> > +	ret = of_property_read_u32(dev->of_node, "maxim,overlap-window",
> > +				   &priv->overlap_window);
> > +	if (ret) {
> > +		dev_err(dev, "Missing property \"maxim,overlap-window\"\n");
> > +		of_node_put(dev->of_node);
> > +		return -EINVAL;
> > +	}
> > +
>
> Other wise, this looks fine except for my concerns and wondering if this
> could be approached by defining a property of the requirements in the
> serializer and parsing that in some form.

As per my previous reply, I had the same concern but mostly for the
reverse channel setting. This is a configuration that applies solely
to the deserializer (at least, that's my understanding not knowing
exactly what this property controls)

>
>
> --
> Kieran
>
> >  	i2c_mux = of_find_node_by_name(dev->of_node, "i2c-mux");
> >  	if (!i2c_mux) {
> >  		dev_err(dev, "Failed to find i2c-mux node\n");
> >
>

Patch
diff mbox series

diff --git a/drivers/media/i2c/max9286.c b/drivers/media/i2c/max9286.c
index 06edd8bd3e82..0357515860b2 100644
--- a/drivers/media/i2c/max9286.c
+++ b/drivers/media/i2c/max9286.c
@@ -117,6 +117,9 @@ 
 #define MAX9286_REV_FLEN(n)		((n) - 20)
 /* Register 0x49 */
 #define MAX9286_VIDEO_DETECT_MASK	0x0f
+/* Register 0x64 */
+#define MAX9286_OVLP_WINDOWH_MASK	GENMASK(4, 0)
+
 /* Register 0x69 */
 #define MAX9286_LFLTBMONMASKED		BIT(7)
 #define MAX9286_LOCKMONMASKED		BIT(6)
@@ -164,6 +167,8 @@  struct max9286_priv {
 	unsigned int csi2_data_lanes;
 	struct max9286_source sources[MAX9286_NUM_GMSL];
 	struct v4l2_async_notifier notifier;
+
+	u32 overlap_window;
 };
 
 static struct max9286_source *next_source(struct max9286_priv *priv,
@@ -895,6 +900,11 @@  static int max9286_setup(struct max9286_priv *priv)
 	max9286_write(priv, 0x01, MAX9286_FSYNCMODE_INT_HIZ |
 		      MAX9286_FSYNCMETH_AUTO);
 
+	/* Configure overlap window. */
+	max9286_write(priv, 0x63, priv->overlap_window);
+	max9286_write(priv, 0x64, (priv->overlap_window >> 8) &
+				  MAX9286_OVLP_WINDOWH_MASK);
+
 	/* Enable HS/VS encoding, use D14/15 for HS/VS, invert VS. */
 	max9286_write(priv, 0x0c, MAX9286_HVEN | MAX9286_INVVS |
 		      MAX9286_HVSRC_D14);
@@ -1041,8 +1051,24 @@  static int max9286_parse_dt(struct max9286_priv *priv)
 	struct device_node *i2c_mux;
 	struct device_node *node = NULL;
 	unsigned int i2c_mux_mask = 0;
+	int ret;
 
 	of_node_get(dev->of_node);
+
+	/*
+	 * FIXM: Require overlap window value to be specified by DTS as long as
+	 * the control function is not clarified. As soon as a default
+	 * behaviour can be established drop this requirement, while older
+	 * DTBs are guaranteed to be fully specified.
+	 */
+	ret = of_property_read_u32(dev->of_node, "maxim,overlap-window",
+				   &priv->overlap_window);
+	if (ret) {
+		dev_err(dev, "Missing property \"maxim,overlap-window\"\n");
+		of_node_put(dev->of_node);
+		return -EINVAL;
+	}
+
 	i2c_mux = of_find_node_by_name(dev->of_node, "i2c-mux");
 	if (!i2c_mux) {
 		dev_err(dev, "Failed to find i2c-mux node\n");