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Subject: Re: [PATCH v7 3/3] media: vimc: Add a control to display info on test
 image
To:     Kaaira Gupta <kgupta@es.iitr.ac.in>
Cc:     Shuah Khan <skhan@linuxfoundation.org>,
        Mauro Carvalho Chehab <mchehab@kernel.org>,
        linux-media@vger.kernel.org, linux-kernel@vger.kernel.org,
        Kieran Bingham <kieran.bingham@ideasonboard.com>,
        hverkuil@xs4all.nl
References: <20200626130700.2453-1-kgupta@es.iitr.ac.in>
 <20200626130700.2453-4-kgupta@es.iitr.ac.in>
 <1409b37e-f03d-cca8-c4a7-e1454f1da910@collabora.com>
 <20200630132510.GA12353@kaaira-HP-Pavilion-Notebook>
From:   Helen Koike <helen.koike@collabora.com>
Message-ID: <56cdfc6a-fdd1-bba7-a479-3b7741d8e011@collabora.com>
Date:   Tue, 30 Jun 2020 10:46:24 -0300
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Hi Kaaira,

On 6/30/20 10:25 AM, Kaaira Gupta wrote:
> On Fri, Jun 26, 2020 at 01:01:03PM -0300, Helen Koike wrote:
>> Hi Kaaira,
>>
>> On 6/26/20 10:07 AM, Kaaira Gupta wrote:
>>> Add a control in VIMC to display information such as the correct order of
>>> colors for a given test pattern, brightness, hue, saturation, contrast,
>>> width and height at sensor over test image.
>>>
>>> Signed-off-by: Kaaira Gupta <kgupta@es.iitr.ac.in>
>>> ---
>>>  drivers/media/test-drivers/vimc/Kconfig       |  2 +
>>>  drivers/media/test-drivers/vimc/vimc-common.h |  1 +
>>>  drivers/media/test-drivers/vimc/vimc-core.c   | 10 +++
>>>  drivers/media/test-drivers/vimc/vimc-sensor.c | 70 +++++++++++++++++++
>>>  4 files changed, 83 insertions(+)
>>>
>>> diff --git a/drivers/media/test-drivers/vimc/Kconfig b/drivers/media/test-drivers/vimc/Kconfig
>>> index 4068a67585f9..da4b2ad6e40c 100644
>>> --- a/drivers/media/test-drivers/vimc/Kconfig
>>> +++ b/drivers/media/test-drivers/vimc/Kconfig
>>> @@ -2,6 +2,8 @@
>>>  config VIDEO_VIMC
>>>  	tristate "Virtual Media Controller Driver (VIMC)"
>>>  	depends on VIDEO_DEV && VIDEO_V4L2
>>> +	select FONT_SUPPORT
>>> +	select FONT_8x16
>>>  	select MEDIA_CONTROLLER
>>>  	select VIDEO_V4L2_SUBDEV_API
>>>  	select VIDEOBUF2_VMALLOC
>>> diff --git a/drivers/media/test-drivers/vimc/vimc-common.h b/drivers/media/test-drivers/vimc/vimc-common.h
>>> index ae163dec2459..a289434e75ba 100644
>>> --- a/drivers/media/test-drivers/vimc/vimc-common.h
>>> +++ b/drivers/media/test-drivers/vimc/vimc-common.h
>>> @@ -20,6 +20,7 @@
>>>  #define VIMC_CID_VIMC_CLASS		(0x00f00000 | 1)
>>>  #define VIMC_CID_TEST_PATTERN		(VIMC_CID_VIMC_BASE + 0)
>>>  #define VIMC_CID_MEAN_WIN_SIZE		(VIMC_CID_VIMC_BASE + 1)
>>> +#define VIMC_CID_OSD_TEXT_MODE		(VIMC_CID_VIMC_BASE + 2)
>>>  
>>>  #define VIMC_FRAME_MAX_WIDTH 4096
>>>  #define VIMC_FRAME_MAX_HEIGHT 2160
>>> diff --git a/drivers/media/test-drivers/vimc/vimc-core.c b/drivers/media/test-drivers/vimc/vimc-core.c
>>> index 11210aaa2551..4b0ae6f51d76 100644
>>> --- a/drivers/media/test-drivers/vimc/vimc-core.c
>>> +++ b/drivers/media/test-drivers/vimc/vimc-core.c
>>> @@ -5,10 +5,12 @@
>>>   * Copyright (C) 2015-2017 Helen Koike <helen.fornazier@gmail.com>
>>>   */
>>>  
>>> +#include <linux/font.h>
>>>  #include <linux/init.h>
>>>  #include <linux/module.h>
>>>  #include <linux/platform_device.h>
>>>  #include <media/media-device.h>
>>> +#include <media/tpg/v4l2-tpg.h>
>>>  #include <media/v4l2-device.h>
>>>  
>>>  #include "vimc-common.h"
>>> @@ -263,11 +265,19 @@ static int vimc_register_devices(struct vimc_device *vimc)
>>>  
>>>  static int vimc_probe(struct platform_device *pdev)
>>>  {
>>> +	const struct font_desc *font = find_font("VGA8x16");
>>>  	struct vimc_device *vimc;
>>>  	int ret;
>>>  
>>>  	dev_dbg(&pdev->dev, "probe");
>>>  
>>> +	if (!font) {
>>> +		dev_err(&pdev->dev, "could not find font\n");
>>> +		return -ENODEV;
>>> +	}
>>> +
>>> +	tpg_set_font(font->data);
>>> +
>>>  	vimc = kzalloc(sizeof(*vimc), GFP_KERNEL);
>>>  	if (!vimc)
>>>  		return -ENOMEM;
>>> diff --git a/drivers/media/test-drivers/vimc/vimc-sensor.c b/drivers/media/test-drivers/vimc/vimc-sensor.c
>>> index a2f09ac9a360..9e4fb3f4d60d 100644
>>> --- a/drivers/media/test-drivers/vimc/vimc-sensor.c
>>> +++ b/drivers/media/test-drivers/vimc/vimc-sensor.c
>>> @@ -19,6 +19,8 @@ struct vimc_sen_device {
>>>  	struct v4l2_subdev sd;
>>>  	struct tpg_data tpg;
>>>  	u8 *frame;
>>> +	unsigned int osd_mode;
>>
>> If you declare the enum outside the below function, this could be type osd_mode instead of unsigned int, what do you think?
>>
>>> +	u64 start_stream_ts;
>>>  	/* The active format */
>>>  	struct v4l2_mbus_framefmt mbus_format;
>>>  	struct v4l2_ctrl_handler hdl;
>>> @@ -187,8 +189,54 @@ static void *vimc_sen_process_frame(struct vimc_ent_device *ved,
>>>  {
>>>  	struct vimc_sen_device *vsen = container_of(ved, struct vimc_sen_device,
>>>  						    ved);
>>> +	enum osd_mode {OSD_SHOW_ALL = 0, OSD_SHOW_COUNTERS = 1, OSD_SHOW_NONE = 2};
>>> +	const unsigned int line_height = 16;
>>> +	u8 *basep[TPG_MAX_PLANES][2];
>>> +	unsigned int line = 1;
>>> +	char str[100];
>>>  
>>>  	tpg_fill_plane_buffer(&vsen->tpg, 0, 0, vsen->frame);
>>> +	tpg_calc_text_basep(&vsen->tpg, basep, 0, vsen->frame);
>>> +	switch (vsen->osd_mode) {
>>> +	case OSD_SHOW_ALL:
>>> +		{
>>
>> Usually we don't use this curly braces in a case statement, please, check other examples in the code,
> 
> I have declared variables inside the cases,hence they are not just
> statements, so I need to use them I think

Doing this grep:

git grep -A1 "case.*:" drivers/media | grep -B1 -P "\tstruct"

I see that the standard is to place the curly braces in the same line of the case statement,
example: https://elixir.bootlin.com/linux/latest/source/drivers/media/v4l2-core/v4l2-subdev.c#L469

> 
>>
>>> +			const char *order = tpg_g_color_order(&vsen->tpg);
>>
>> You also don't need this level of identation.
> 
> I used it because of the braces

Please check the example above

> 
>>
>>> +
>>> +			tpg_gen_text(&vsen->tpg, basep,
>>> +				     line++ * line_height, 16, order);
>>> +			snprintf(str, sizeof(str),
>>> +				 "brightness %3d, contrast %3d, saturation %3d, hue %d ",
>>> +				 vsen->tpg.brightness,
>>> +				 vsen->tpg.contrast,
>>> +				 vsen->tpg.saturation,
>>> +				 vsen->tpg.hue);
>>> +			tpg_gen_text(&vsen->tpg, basep, line++ * line_height,
>>> +				     16, str);
>>> +			snprintf(str, sizeof(str), "sensor size: %dx%d",
>>> +				 vsen->mbus_format.width,
>>> +				 vsen->mbus_format.height);
>>> +			tpg_gen_text(&vsen->tpg, basep, line++ * line_height,
>>> +				     16, str);
>>> +		}
>>> +	case OSD_SHOW_COUNTERS:
>>
>> Checkpatch gives this error:
>>
>> WARNING: Possible switch case/default not preceded by break or fallthrough comment
>>
>> You need to add a fallthrough comment (grep for fallthrough to find other examples)
> 
> Okay, I will add that
> 
>>
>>> +		{
>>> +			unsigned int ms;
>>> +
>>> +			ms = (ktime_get_ns() - vsen->start_stream_ts) / 1000000;
>>> +			snprintf(str, sizeof(str), "%02d:%02d:%02d:%03d",
>>> +				 (ms / (60 * 60 * 1000)) % 24,
>>> +				 (ms / (60 * 1000)) % 60,
>>> +				 (ms / 1000) % 60,
>>> +				 ms % 1000);
>>> +			tpg_gen_text(&vsen->tpg, basep, line++ * line_height,
>>> +				     16, str);
>>> +			break;
>>> +		}
>>> +	case OSD_SHOW_NONE:
>>
>> No need this case statement if you have the default below.
> 
> I added it to make it clearer what default does, should I remove it?

hmm, I think this depends on your style, but to me, just the "default" statement below makes it
clear that options not listed above do nothing.
I think you would also need to add a fallthtough comment.

Or you could just add a comment instead of the case statement in the code, like:

	/* case OSD_SHOW_NONE: */

So it would be clear what this option does.

Regards,
Helen

> 
>>
>> Regards,
>> Helen
>>
>>> +	default:
>>> +		break;
>>> +	}
>>> +
>>>  	return vsen->frame;
>>>  }
>>>  
>>> @@ -201,6 +249,8 @@ static int vimc_sen_s_stream(struct v4l2_subdev *sd, int enable)
>>>  		const struct vimc_pix_map *vpix;
>>>  		unsigned int frame_size;
>>>  
>>> +		vsen->start_stream_ts = ktime_get_ns();
>>> +
>>>  		/* Calculate the frame size */
>>>  		vpix = vimc_pix_map_by_code(vsen->mbus_format.code);
>>>  		frame_size = vsen->mbus_format.width * vpix->bpp *
>>> @@ -269,6 +319,9 @@ static int vimc_sen_s_ctrl(struct v4l2_ctrl *ctrl)
>>>  	case V4L2_CID_SATURATION:
>>>  		tpg_s_saturation(&vsen->tpg, ctrl->val);
>>>  		break;
>>> +	case VIMC_CID_OSD_TEXT_MODE:
>>> +		vsen->osd_mode = ctrl->val;
>>> +		break;
>>>  	default:
>>>  		return -EINVAL;
>>>  	}
>>> @@ -307,6 +360,22 @@ static const struct v4l2_ctrl_config vimc_sen_ctrl_test_pattern = {
>>>  	.qmenu = tpg_pattern_strings,
>>>  };
>>>  
>>> +static const char * const vimc_ctrl_osd_mode_strings[] = {
>>> +	"All",
>>> +	"Counters Only",
>>> +	"None",
>>> +	NULL,
>>> +};
>>> +
>>> +static const struct v4l2_ctrl_config vimc_sen_ctrl_osd_mode = {
>>> +	.ops = &vimc_sen_ctrl_ops,
>>> +	.id = VIMC_CID_OSD_TEXT_MODE,
>>> +	.name = "Show Information",
>>> +	.type = V4L2_CTRL_TYPE_MENU,
>>> +	.max = ARRAY_SIZE(vimc_ctrl_osd_mode_strings) - 2,
>>> +	.qmenu = vimc_ctrl_osd_mode_strings,
>>> +};
>>> +
>>>  static struct vimc_ent_device *vimc_sen_add(struct vimc_device *vimc,
>>>  					    const char *vcfg_name)
>>>  {
>>> @@ -323,6 +392,7 @@ static struct vimc_ent_device *vimc_sen_add(struct vimc_device *vimc,
>>>  
>>>  	v4l2_ctrl_new_custom(&vsen->hdl, &vimc_sen_ctrl_class, NULL);
>>>  	v4l2_ctrl_new_custom(&vsen->hdl, &vimc_sen_ctrl_test_pattern, NULL);
>>> +	v4l2_ctrl_new_custom(&vsen->hdl, &vimc_sen_ctrl_osd_mode, NULL);
>>>  	v4l2_ctrl_new_std(&vsen->hdl, &vimc_sen_ctrl_ops,
>>>  			  V4L2_CID_VFLIP, 0, 1, 1, 0);
>>>  	v4l2_ctrl_new_std(&vsen->hdl, &vimc_sen_ctrl_ops,
>>>