RE: [PATCH V7 4/4] media: i2c: imx334: add modes for 720p and 480p resolutions

[Kieran Bingham <kieran.bingham@ideasonboard.com>]

Quoting Shravan.Chippa@microchip.com (2025-03-05 10:22:12)
> Hi Kieran
> 
> > -----Original Message-----
> > From: Kieran Bingham <kieran.bingham@ideasonboard.com>
> > Sent: Wednesday, March 5, 2025 3:05 PM
> > To: mchehab@kernel.org; sakari.ailus@linux.intel.com; shravan Chippa -
> > I35088 <Shravan.Chippa@microchip.com>
> > Cc: linux-media@vger.kernel.org; linux-kernel@vger.kernel.org; Conor Dooley
> > - M52691 <Conor.Dooley@microchip.com>; Valentina Fernandez Alanis -
> > M63239 <Valentina.FernandezAlanis@microchip.com>; Praveen Kumar -
> > I30718 <Praveen.Kumar@microchip.com>; shravan Chippa - I35088
> > <Shravan.Chippa@microchip.com>
> > Subject: Re: [PATCH V7 4/4] media: i2c: imx334: add modes for 720p and 480p
> > resolutions
> > 
> > EXTERNAL EMAIL: Do not click links or open attachments unless you know the
> > content is safe
> > 
> > Quoting shravan kumar (2025-03-05 05:14:42)
> > > From: Shravan Chippa <shravan.chippa@microchip.com>
> > >
> > > Added support for 1280x720@30 and 640x480@30 resolutions
> > >
> > > Signed-off-by: Shravan Chippa <shravan.chippa@microchip.com>
> > > ---
> > >  drivers/media/i2c/imx334.c | 66
> > > ++++++++++++++++++++++++++++++++++++++
> > >  1 file changed, 66 insertions(+)
> > >
> > > diff --git a/drivers/media/i2c/imx334.c b/drivers/media/i2c/imx334.c
> > > index a7c0bd38c9b8..8cd1eecd0143 100644
> > > --- a/drivers/media/i2c/imx334.c
> > > +++ b/drivers/media/i2c/imx334.c
> > > @@ -314,6 +314,46 @@ static const struct imx334_reg
> > common_mode_regs[] = {
> > >         {0x3002, 0x00},
> > >  };
> > >
> > > +/* Sensor mode registers for 640x480@30fps */ static const struct
> > > +imx334_reg mode_640x480_regs[] = {
> > > +       {0x302c, 0x70},
> > > +       {0x302d, 0x06},
> > 
> > These two are a single 16 bit register HTRIMMING_START = 1648
> > 
> > > +       {0x302e, 0x80},
> > > +       {0x302f, 0x02},
> > 
> > These two are a single 16 bit register HNUM = 640
> > 
> > > +       {0x3074, 0x48},
> > > +       {0x3075, 0x07},
> > 
> > These two are a single 16 bit (well, 12 bit value) AREA3_ST_ADR_1 = 1864
> > 
> > > +       {0x308e, 0x49},
> > > +       {0x308f, 0x07},
> > 
> > These two are a single 16 bit register AREA3_ST_ADR_2 = 1865
> > 
> > > +       {0x3076, 0xe0},
> > > +       {0x3077, 0x01},
> > 
> > These two are a single 16 bit register AREA3_WIDTH_1 = 480
> > 
> > > +       {0x3090, 0xe0},
> > > +       {0x3091, 0x01},
> > 
> > These two are a single 16 bit register AREA3_WIDTH_2 = 480
> > 
> > > +       {0x3308, 0xe0},
> > > +       {0x3309, 0x01},
> > 
> > These two are a single 16 bit register Y_OUT_SIZE
> > 
> > Don't you think
> >         { Y_OUT_SIZE, 480 },
> > 
> > Is so much more readable and easier to comprehend and maintain?
> > 
> > 
> > > +       {0x30d8, 0x30},
> > > +       {0x30d9, 0x0b},
> > 
> > These two are a single 16 bit register UNREAD_ED_ADR = 2864
> > 
> > > +};
> > 
> > I'm still sad that we can all know the names of all these registers and yet this
> > is writing new tables of hex values.
> 
> Do you want me use call like bellow API with register names:
> CCI_REG16_LE(0x30d8);
> cci_write();
> cci_multi_reg_write();
> devm_cci_regmap_init_i2c();
 

Yes please, I would want that very much. I'm not very good at reading
and storing hex values in my head! That's why I broke down the above
registers to strings and decimal values.


The discussions at
https://lore.kernel.org/all/PH0PR11MB5611FD22CF6E12F7226FA9C081E12@PH0PR11MB5611.namprd11.prod.outlook.com/
reports the full datasheet, and I stated:


> > > This is an enormous amount of duplicated data that could be factored
> > > out.
> > >
> > > These are also /very/ common against the existing mode register
> > > tables too.
> > >
> > > I think several things need to happen in this driver:
> > >
> > >  1. It should be converted to use the CCI helpers.
> > >  2. Whereever identifiable, the register names should be used
> > > instead of
> > >     just the addresses.
> > >  3. The common factors of these tables should be de-duplicated.
> > >
> > > In your additions you only have differences in the following
> > > registers from those entire tables:

You replied with

> >
> > I will try to optimize camera resolution array register value usage by
> > writing common register array values.

which you have done (point 3), and is great progress in the series.

Further down in the thread I stated:


> > >  4. And ideally - the differences which determine the modes should
> > > be
> > >     factored out to calculations so that we are not writing out
> > > large
> > >     tables just to write a parameterised frame size.
> > >
> > >
> > > I would beleive that at least steps 1 and 3 would be achievable, 2
> > > and 4 would depend upon access to the datasheet.
> > >


I still believe steps 1 is important to this development. You have done
step 3 I think. And now both step 2 and (later) step 4 are possible as we
have the datasheet.

--
Kieran


> 
> Thanks,
> Shravan
> > 
> > 
> > --
> > Kieran
> > 
> > 
> > > +
> > > +/* Sensor mode registers for 1280x720@30fps */ static const struct
> > > +imx334_reg mode_1280x720_regs[] = {
> > > +       {0x302c, 0x30},
> > > +       {0x302d, 0x05},
> > > +       {0x302e, 0x00},
> > > +       {0x302f, 0x05},
> > > +       {0x3074, 0x84},
> > > +       {0x3075, 0x03},
> > > +       {0x308e, 0x85},
> > > +       {0x308f, 0x03},
> > > +       {0x3076, 0xd0},
> > > +       {0x3077, 0x02},
> > > +       {0x3090, 0xd0},
> > > +       {0x3091, 0x02},
> > > +       {0x3308, 0xd0},
> > > +       {0x3309, 0x02},
> > > +       {0x30d8, 0x30},
> > > +       {0x30d9, 0x0b},
> > > +};
> > > +
> > >  /* Sensor mode registers for 1920x1080@30fps */  static const struct
> > > imx334_reg mode_1920x1080_regs[] = {
> > >         {0x302c, 0xf0},
> > > @@ -433,6 +473,32 @@ static const struct imx334_mode
> > supported_modes[] = {
> > >                         .num_of_regs = ARRAY_SIZE(mode_1920x1080_regs),
> > >                         .regs = mode_1920x1080_regs,
> > >                 },
> > > +       }, {
> > > +               .width = 1280,
> > > +               .height = 720,
> > > +               .hblank = 2480,
> > > +               .vblank = 1170,
> > > +               .vblank_min = 45,
> > > +               .vblank_max = 132840,
> > > +               .pclk = 297000000,
> > > +               .link_freq_idx = 1,
> > > +               .reg_list = {
> > > +                       .num_of_regs = ARRAY_SIZE(mode_1280x720_regs),
> > > +                       .regs = mode_1280x720_regs,
> > > +               },
> > > +       }, {
> > > +               .width = 640,
> > > +               .height = 480,
> > > +               .hblank = 2480,
> > > +               .vblank = 1170,
> > > +               .vblank_min = 45,
> > > +               .vblank_max = 132840,
> > > +               .pclk = 297000000,
> > > +               .link_freq_idx = 1,
> > > +               .reg_list = {
> > > +                       .num_of_regs = ARRAY_SIZE(mode_640x480_regs),
> > > +                       .regs = mode_640x480_regs,
> > > +               },
> > >         },
> > >  };
> > >
> > > --
> > > 2.34.1
> > >