Re: [PATCH RFC] media: i2c: mt9p031: add OF support

From: Laurent Pinchart
Date: Mon Apr 29 2013 - 07:35:28 EST

Hi Prabhakar,

Thank you for the patch. Please see below for a couple of comments in addition
to the ones I've just sent (in reply to Sascha's e-mail).

On Monday 29 April 2013 13:30:01 Prabhakar Lad wrote:
> From: Lad, Prabhakar <prabhakar.csengg@xxxxxxxxx>
>
> add OF support for the mt9p031 sensor driver.
>
> Signed-off-by: Lad, Prabhakar <prabhakar.csengg@xxxxxxxxx>
> Cc: Hans Verkuil <hans.verkuil@xxxxxxxxx>
> Cc: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
> Cc: Mauro Carvalho Chehab <mchehab@xxxxxxxxxx>
> Cc: Guennadi Liakhovetski <g.liakhovetski@xxxxxx>
> Cc: Sylwester Nawrocki <s.nawrocki@xxxxxxxxxxx>
> Cc: Sakari Ailus <sakari.ailus@xxxxxx>
> Cc: Grant Likely <grant.likely@xxxxxxxxxxxx>
> Cc: Rob Herring <rob.herring@xxxxxxxxxxx>
> Cc: Rob Landley <rob@xxxxxxxxxxx>
> Cc: devicetree-discuss@xxxxxxxxxxxxxxxx
> Cc: linux-doc@xxxxxxxxxxxxxxx
> Cc: linux-kernel@xxxxxxxxxxxxxxx

[snip]

> ---
> .../devicetree/bindings/media/i2c/mt9p031.txt | 43 ++++++++++++++
> drivers/media/i2c/mt9p031.c | 61 ++++++++++++++++-
> 2 files changed, 103 insertions(+), 1 deletions(-)
> create mode 100644 Documentation/devicetree/bindings/media/i2c/mt9p031.txt
>
> diff --git a/Documentation/devicetree/bindings/media/i2c/mt9p031.txt
> b/Documentation/devicetree/bindings/media/i2c/mt9p031.txt new file mode
> 100644
> index 0000000..b985e63
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/media/i2c/mt9p031.txt
> @@ -0,0 +1,43 @@
> +* Aptina 1/2.5-Inch 5Mp CMOS Digital Image Sensor
> +
> +The Aptina MT9P031 is a 1/2.5-inch CMOS active pixel digital image sensor
> +with an active imaging pixel array of 2592H x 1944V. It incorporates
> +sophisticated camera functions on-chip such as windowing, column and row
> +skip mode, and snapshot mode. It is programmable through a simple two-wire
> +serial interface.
> +The MT9P031 is a progressive-scan sensor that generates a stream of pixel
> +data at a constant frame rate. It uses an on-chip, phase-locked loop (PLL)
> +to generate all internal clocks from a single master input clock running
> +between 6 and 27 MHz. The maximum pixel rate is 96 Mp/s, corresponding to
> +a clock rate of 96 MHz.

Isn't this text (directly copied from the datasheet) under Aptina's copyright
?

> +Required Properties :
> +- compatible : value should be either one among the following
> + (a) "aptina,mt9p031-sensor" for mt9p031 sensor
> + (b) "aptina,mt9p031m-sensor" for mt9p031m sensor
> +
> +- ext_freq: Input clock frequency.
> +
> +- target_freq: Pixel clock frequency.
> +
> +Optional Properties :
> +-reset: Chip reset GPIO (If not specified defaults to -1)
> +
> +Example:
> +
> +i2c0@1c22000 {
> + ...
> + ...
> + mt9p031@5d {
> + compatible = "aptina,mt9p031-sensor";
> + reg = <0x5d>;
> +
> + port {
> + mt9p031_1: endpoint {
> + ext_freq = <6000000>;
> + target_freq = <96000000>;
> + };
> + };
> + };
> + ...
> +};
> \ No newline at end of file
> diff --git a/drivers/media/i2c/mt9p031.c b/drivers/media/i2c/mt9p031.c
> index 28cf95b..66078a6 100644
> --- a/drivers/media/i2c/mt9p031.c
> +++ b/drivers/media/i2c/mt9p031.c
> @@ -23,11 +23,13 @@
> #include <linux/regulator/consumer.h>
> #include <linux/slab.h>
> #include <linux/videodev2.h>
> +#include <linux/of_device.h>
>
> #include <media/mt9p031.h>
> #include <media/v4l2-chip-ident.h>
> #include <media/v4l2-ctrls.h>
> #include <media/v4l2-device.h>
> +#include <media/v4l2-of.h>
> #include <media/v4l2-subdev.h>
>
> #include "aptina-pll.h"
> @@ -928,10 +930,66 @@ static const struct v4l2_subdev_internal_ops
> mt9p031_subdev_internal_ops = { * Driver initialization and probing
> */
>
> +#if defined(CONFIG_OF)
> +static const struct of_device_id mt9p031_of_match[] = {
> + {.compatible = "aptina,mt9p031-sensor", },
> + {.compatible = "aptina,mt9p031m-sensor", },

As you'll need to resubmit anyway, please add a space between '{' and '.'

> + {},
> +};
> +MODULE_DEVICE_TABLE(of, mt9p031_of_match);
> +
> +static struct mt9p031_platform_data
> + *mt9p031_get_pdata(struct i2c_client *client)
> +
> +{
> + if (!client->dev.platform_data && client->dev.of_node) {
> + struct device_node *np;
> + struct mt9p031_platform_data *pdata;
> + int ret;
> +
> + np = v4l2_of_get_next_endpoint(client->dev.of_node, NULL);
> + if (!np)
> + return NULL;
> +
> + pdata = devm_kzalloc(&client->dev,
> + sizeof(struct mt9p031_platform_data),
> + GFP_KERNEL);
> + if (!pdata) {
> + pr_warn("mt9p031 failed allocate memeory\n");
> + return NULL;
> + }
> + ret = of_property_read_u32(np, "reset", &pdata->reset);
> + if (ret == -EINVAL)
> + pdata->reset = -1;
> + else if (ret == -ENODATA)
> + return NULL;
> +
> + if (of_property_read_u32(np, "ext_freq", &pdata->ext_freq))
> + return NULL;
> +
> + if (of_property_read_u32(np, "target_freq",
> + &pdata->target_freq))
> + return NULL;
> +
> + return pdata;
> + }
> +
> + return NULL;
> +}
> +#else
> +#define mt9p031_of_match NULL
> +
> +static struct mt9p031_platform_data
> + *mt9p031_get_pdata(struct i2c_client *client)
> +{
> + return client->dev.platform_data;
> +}
> +#endif
> +
> static int mt9p031_probe(struct i2c_client *client,
> const struct i2c_device_id *did)
> {
> - struct mt9p031_platform_data *pdata = client->dev.platform_data;
> + struct mt9p031_platform_data *pdata = mt9p031_get_pdata(client);
> struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent);
> struct mt9p031 *mt9p031;
> unsigned int i;
> @@ -1072,6 +1130,7 @@ MODULE_DEVICE_TABLE(i2c, mt9p031_id);
>
> static struct i2c_driver mt9p031_i2c_driver = {
> .driver = {
> + .of_match_table = mt9p031_of_match,

You can use the of_match_ptr() macro instead of defining mt9p031_of_match as
NULL above.

> .name = "mt9p031",
> },
> .probe = mt9p031_probe,
--
Regards,

Laurent Pinchart

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