diff mbox

[v2,5/5] em28xx: write output frame resolution to regs 0x34+0x35 for em25xx family bridges

Message ID 1364059632-29070-6-git-send-email-fschaefer.oss@googlemail.com (mailing list archive)
State New, archived
Headers show

Commit Message

Frank Schäfer March 23, 2013, 5:27 p.m. UTC 
The Windows driver writes the output resolution to registers 0x34 (width / 16)
and 0x35 (height / 16) always.
We don't know yet what these registers are used for.

Signed-off-by: Frank Schäfer <fschaefer.oss@googlemail.com>
---
 drivers/media/usb/em28xx/em28xx-core.c |    7 +++++++
 drivers/media/usb/em28xx/em28xx-reg.h  |    6 ++++++
 2 Dateien geändert, 13 Zeilen hinzugefügt(+)

Comments

Mauro Carvalho Chehab March 24, 2013, 11:44 a.m. UTC | #1 
Em Sat, 23 Mar 2013 18:27:12 +0100
Frank Schäfer <fschaefer.oss@googlemail.com> escreveu:

> The Windows driver writes the output resolution to registers 0x34 (width / 16)
> and 0x35 (height / 16) always.
> We don't know yet what these registers are used for.
> 
> Signed-off-by: Frank Schäfer <fschaefer.oss@googlemail.com>
> ---
>  drivers/media/usb/em28xx/em28xx-core.c |    7 +++++++
>  drivers/media/usb/em28xx/em28xx-reg.h  |    6 ++++++
>  2 Dateien geändert, 13 Zeilen hinzugefügt(+)
> 
> diff --git a/drivers/media/usb/em28xx/em28xx-core.c b/drivers/media/usb/em28xx/em28xx-core.c
> index 7b9f76b..0ce6b0f 100644
> --- a/drivers/media/usb/em28xx/em28xx-core.c
> +++ b/drivers/media/usb/em28xx/em28xx-core.c
> @@ -766,6 +766,13 @@ static void em28xx_capture_area_set(struct em28xx *dev, u8 hstart, u8 vstart,
>  	em28xx_write_regs(dev, EM28XX_R1E_CWIDTH, &cwidth, 1);
>  	em28xx_write_regs(dev, EM28XX_R1F_CHEIGHT, &cheight, 1);
>  	em28xx_write_regs(dev, EM28XX_R1B_OFLOW, &overflow, 1);
> +
> +	if (dev->is_em25xx) {
> +		em28xx_write_reg(dev, 0x34, width >> 4);
> +		em28xx_write_reg(dev, 0x35, height >> 4);
> +	}
> +	/* FIXME: function/meaning of these registers ? */
> +	/* FIXME: */

Please move those comments to be _before_ the code you're commenting.

E. g. something like:

	if (dev->is_em25xx) {
		/*
		 * FIXME:
 		 *	- function/meaning of these registers are unknown;
		 *	- align width+height to multiples of 4 ?! 
		 */
		em28xx_write_reg(dev, 0x34, width >> 4);
		em28xx_write_reg(dev, 0x35, height >> 4);
	}


>  }
>  
>  static int em28xx_scaler_set(struct em28xx *dev, u16 h, u16 v)
> diff --git a/drivers/media/usb/em28xx/em28xx-reg.h b/drivers/media/usb/em28xx/em28xx-reg.h
> index 1b0ecd6..e08982a 100644
> --- a/drivers/media/usb/em28xx/em28xx-reg.h
> +++ b/drivers/media/usb/em28xx/em28xx-reg.h
> @@ -167,6 +167,12 @@
>  
>  #define EM28XX_R34_VBI_START_H	0x34
>  #define EM28XX_R35_VBI_START_V	0x35
> +/* NOTE: the EM276x (and EM25xx, EM277x/8x ?) (camera bridges) use these
> + * registers for a different unknown purpose.
> + *   => register 0x34 is set to capture width / 16
> + *   => register 0x35 is set to capture height / 16
> + */
> +
>  #define EM28XX_R36_VBI_WIDTH	0x36
>  #define EM28XX_R37_VBI_HEIGHT	0x37
>
Frank Schäfer March 24, 2013, 12:56 p.m. UTC | #2 
Am 24.03.2013 12:44, schrieb Mauro Carvalho Chehab:
> Em Sat, 23 Mar 2013 18:27:12 +0100
> Frank Schäfer <fschaefer.oss@googlemail.com> escreveu:
>
>> The Windows driver writes the output resolution to registers 0x34 (width / 16)
>> and 0x35 (height / 16) always.
>> We don't know yet what these registers are used for.
>>
>> Signed-off-by: Frank Schäfer <fschaefer.oss@googlemail.com>
>> ---
>>  drivers/media/usb/em28xx/em28xx-core.c |    7 +++++++
>>  drivers/media/usb/em28xx/em28xx-reg.h  |    6 ++++++
>>  2 Dateien geändert, 13 Zeilen hinzugefügt(+)
>>
>> diff --git a/drivers/media/usb/em28xx/em28xx-core.c b/drivers/media/usb/em28xx/em28xx-core.c
>> index 7b9f76b..0ce6b0f 100644
>> --- a/drivers/media/usb/em28xx/em28xx-core.c
>> +++ b/drivers/media/usb/em28xx/em28xx-core.c
>> @@ -766,6 +766,13 @@ static void em28xx_capture_area_set(struct em28xx *dev, u8 hstart, u8 vstart,
>>  	em28xx_write_regs(dev, EM28XX_R1E_CWIDTH, &cwidth, 1);
>>  	em28xx_write_regs(dev, EM28XX_R1F_CHEIGHT, &cheight, 1);
>>  	em28xx_write_regs(dev, EM28XX_R1B_OFLOW, &overflow, 1);
>> +
>> +	if (dev->is_em25xx) {
>> +		em28xx_write_reg(dev, 0x34, width >> 4);
>> +		em28xx_write_reg(dev, 0x35, height >> 4);
>> +	}
>> +	/* FIXME: function/meaning of these registers ? */
>> +	/* FIXME: align width+height to multiples of 4 ?! */
> Please move those comments to be _before_ the code you're commenting.
>
> E. g. something like:
>
> 	if (dev->is_em25xx) {
> 		/*
> 		 * FIXME:
>  		 *	- function/meaning of these registers are unknown;
> 		 *	- align width+height to multiples of 4 ?! 
> 		 */
> 		em28xx_write_reg(dev, 0x34, width >> 4);
> 		em28xx_write_reg(dev, 0x35, height >> 4);
> 	}

Ok, no problem.

Frank

>
>>  }
>>  
>>  static int em28xx_scaler_set(struct em28xx *dev, u16 h, u16 v)
>> diff --git a/drivers/media/usb/em28xx/em28xx-reg.h b/drivers/media/usb/em28xx/em28xx-reg.h
>> index 1b0ecd6..e08982a 100644
>> --- a/drivers/media/usb/em28xx/em28xx-reg.h
>> +++ b/drivers/media/usb/em28xx/em28xx-reg.h
>> @@ -167,6 +167,12 @@
>>  
>>  #define EM28XX_R34_VBI_START_H	0x34
>>  #define EM28XX_R35_VBI_START_V	0x35
>> +/* NOTE: the EM276x (and EM25xx, EM277x/8x ?) (camera bridges) use these
>> + * registers for a different unknown purpose.
>> + *   => register 0x34 is set to capture width / 16
>> + *   => register 0x35 is set to capture height / 16
>> + */
>> +
>>  #define EM28XX_R36_VBI_WIDTH	0x36
>>  #define EM28XX_R37_VBI_HEIGHT	0x37
>>  
>

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diff mbox

Patch

diff --git a/drivers/media/usb/em28xx/em28xx-core.c b/drivers/media/usb/em28xx/em28xx-core.c
index 7b9f76b..0ce6b0f 100644
--- a/drivers/media/usb/em28xx/em28xx-core.c
+++ b/drivers/media/usb/em28xx/em28xx-core.c
@@ -766,6 +766,13 @@  static void em28xx_capture_area_set(struct em28xx *dev, u8 hstart, u8 vstart,
 	em28xx_write_regs(dev, EM28XX_R1E_CWIDTH, &cwidth, 1);
 	em28xx_write_regs(dev, EM28XX_R1F_CHEIGHT, &cheight, 1);
 	em28xx_write_regs(dev, EM28XX_R1B_OFLOW, &overflow, 1);
+
+	if (dev->is_em25xx) {
+		em28xx_write_reg(dev, 0x34, width >> 4);
+		em28xx_write_reg(dev, 0x35, height >> 4);
+	}
+	/* FIXME: function/meaning of these registers ? */
+	/* FIXME: align width+height to multiples of 4 ?! */
 }
 
 static int em28xx_scaler_set(struct em28xx *dev, u16 h, u16 v)
diff --git a/drivers/media/usb/em28xx/em28xx-reg.h b/drivers/media/usb/em28xx/em28xx-reg.h
index 1b0ecd6..e08982a 100644
--- a/drivers/media/usb/em28xx/em28xx-reg.h
+++ b/drivers/media/usb/em28xx/em28xx-reg.h
@@ -167,6 +167,12 @@ 
 
 #define EM28XX_R34_VBI_START_H	0x34
 #define EM28XX_R35_VBI_START_V	0x35
+/* NOTE: the EM276x (and EM25xx, EM277x/8x ?) (camera bridges) use these
+ * registers for a different unknown purpose.
+ *   => register 0x34 is set to capture width / 16
+ *   => register 0x35 is set to capture height / 16
+ */
+
 #define EM28XX_R36_VBI_WIDTH	0x36
 #define EM28XX_R37_VBI_HEIGHT	0x37