Re: [PATCH v7 07/11] media: i2c: ov772x: Support frame interval handling

jacopo mondi
2018-01-30T09:47:51Z

Hi Laurent,

On Mon, Jan 29, 2018 at 01:01:01PM +0200, Laurent Pinchart wrote:
> Hi Jacopo,
>
> Thank you for the patch.
>
> On Friday, 26 January 2018 15:55:26 EET Jacopo Mondi wrote:
> > Add support to ov772x driver for frame intervals handling and enumeration.
> > Tested with 10MHz and 24MHz input clock at VGA and QVGA resolutions for
> > 10, 15 and 30 frame per second rates.
> >
> > Signed-off-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
> > ---
> > drivers/media/i2c/ov772x.c | 315 +++++++++++++++++++++++++++++++++++++++++-
> > 1 file changed, 310 insertions(+), 5 deletions(-)
> >
> > diff --git a/drivers/media/i2c/ov772x.c b/drivers/media/i2c/ov772x.c
> > index 912b1b9..6d46748 100644
> > --- a/drivers/media/i2c/ov772x.c
> > +++ b/drivers/media/i2c/ov772x.c
> > @@ -250,6 +250,7 @@
> > #define AEC_1p2 0x10 /* 01: 1/2 window */
> > #define AEC_1p4 0x20 /* 10: 1/4 window */
> > #define AEC_2p3 0x30 /* 11: Low 2/3 window */
> > +#define COM4_RESERVED 0x01 /* Reserved value */
>
> I'd write "Reserved bits", "Reserved value" makes it sound like it's the value
> of the full register.
>

Ack

> > /* COM5 */
> > #define AFR_ON_OFF 0x80 /* Auto frame rate control ON/OFF selection
> */
> > @@ -267,6 +268,19 @@
> > /* AEC max step control */
> > #define AEC_NO_LIMIT 0x01 /* 0 : AEC incease step has limit */
> > /* 1 : No limit to AEC increase step */
> > +/* CLKRC */
> > + /* Input clock divider register */
> > +#define CLKRC_RESERVED 0x80 /* Reserved value */
> > +#define CLKRC_BYPASS 0x40 /* Bypass input clock divider */
> > +#define CLKRC_DIV2 0x01 /* Divide input clock by 2 */
> > +#define CLKRC_DIV3 0x02 /* Divide input clock by 3 */
> > +#define CLKRC_DIV4 0x03 /* Divide input clock by 4 */
> > +#define CLKRC_DIV5 0x04 /* Divide input clock by 5 */
> > +#define CLKRC_DIV6 0x05 /* Divide input clock by 6 */
> > +#define CLKRC_DIV8 0x07 /* Divide input clock by 8 */
> > +#define CLKRC_DIV10 0x09 /* Divide input clock by 10 */
> > +#define CLKRC_DIV16 0x0f /* Divide input clock by 16 */
> > +#define CLKRC_DIV20 0x13 /* Divide input clock by 20 */
>
> How about just
>
> #define CLKRC_DIV(n) ((n) - 1)
>

Ack again,

> > /* COM7 */
> > /* SCCB Register Reset */
> > @@ -373,6 +387,12 @@
> > #define VERSION(pid, ver) ((pid<<8)|(ver&0xFF))
> >
> > /*
> > + * Input clock frequencies
> > + */
> > +enum { OV772X_FIN_10MHz, OV772X_FIN_24MHz, OV772X_FIN_48MHz, OV772X_FIN_N,
> > };
> > +static unsigned int ov772x_fin_vals[] = { 10000000, 24000000, 48000000
> > };
> > +
> > +/*
> > * struct
> > */
> >
> > @@ -391,6 +411,16 @@ struct ov772x_win_size {
> > struct v4l2_rect rect;
> > };
> >
> > +struct ov772x_pclk_config {
> > + u8 com4;
> > + u8 clkrc;
> > +};
> > +
> > +struct ov772x_frame_rate {
> > + unsigned int fps;
> > + const struct ov772x_pclk_config pclk[OV772X_FIN_N];
> > +};
> > +
> > struct ov772x_priv {
> > struct v4l2_subdev subdev;
> > struct v4l2_ctrl_handler hdl;
> > @@ -404,6 +434,7 @@ struct ov772x_priv {
> > unsigned short flag_hflip:1;
> > /* band_filter = COM8[5] ? 256 - BDBASE : 0 */
> > unsigned short band_filter;
> > + unsigned int fps;
> > };
> >
> > /*
> > @@ -508,6 +539,154 @@ static const struct ov772x_win_size ov772x_win_sizes[]
> > = { };
> >
> > /*
> > + * frame rate settings lists
> > + */
> > +unsigned int ov772x_frame_intervals[] = {10, 15, 30, 60};
> > +#define OV772X_N_FRAME_INTERVALS ARRAY_SIZE(ov772x_frame_intervals)
> > +
> > +static const struct ov772x_frame_rate vga_frame_rates[] = {
> > + { /* PCLK = 7,5 MHz */
> > + .fps = 10,
> > + .pclk = {
> > + [OV772X_FIN_10MHz] = {
> > + .com4 = PLL_6x | COM4_RESERVED,
> > + .clkrc = CLKRC_DIV8 | CLKRC_RESERVED,
> > + },
> > + [OV772X_FIN_24MHz] = {
> > + .com4 = PLL_BYPASS | COM4_RESERVED,
> > + .clkrc = CLKRC_DIV3 | CLKRC_RESERVED,
> > + },
> > + [OV772X_FIN_48MHz] = {
> > + .com4 = PLL_BYPASS | COM4_RESERVED,
> > + .clkrc = CLKRC_DIV6 | CLKRC_RESERVED,
> > + },
> > + },
> > + },
> > + { /* PCLK = 12 MHz */
> > + .fps = 15,
> > + .pclk = {
> > + [OV772X_FIN_10MHz] = {
> > + .com4 = PLL_4x | COM4_RESERVED,
> > + .clkrc = CLKRC_DIV3 | CLKRC_RESERVED,
> > + },
> > + [OV772X_FIN_24MHz] = {
> > + .com4 = PLL_BYPASS | COM4_RESERVED,
> > + .clkrc = CLKRC_DIV2 | CLKRC_RESERVED,
> > + },
> > + [OV772X_FIN_48MHz] = {
> > + .com4 = PLL_BYPASS | COM4_RESERVED,
> > + .clkrc = CLKRC_DIV4 | CLKRC_RESERVED,
> > + },
> > + },
> > + },
> > + { /* PCLK = 24 MHz */
> > + .fps = 30,
> > + .pclk = {
> > + [OV772X_FIN_10MHz] = {
> > + .com4 = PLL_8x | COM4_RESERVED,
> > + .clkrc = CLKRC_DIV3 | CLKRC_RESERVED,
> > + },
> > + [OV772X_FIN_24MHz] = {
> > + .com4 = PLL_BYPASS | COM4_RESERVED,
> > + .clkrc = CLKRC_BYPASS | CLKRC_RESERVED,
> > + },
> > + [OV772X_FIN_48MHz] = {
> > + .com4 = PLL_BYPASS | COM4_RESERVED,
> > + .clkrc = CLKRC_DIV2 | CLKRC_RESERVED,
> > + },
> > + },
> > + },
> > + { /* PCLK = 48 MHz */
> > + .fps = 60,
> > + .pclk = {
> > + [OV772X_FIN_10MHz] = {
> > + .com4 = PLL_8x | COM4_RESERVED,
> > + .clkrc = CLKRC_DIV2 | CLKRC_RESERVED,
> > + },
> > + [OV772X_FIN_24MHz] = {
> > + .com4 = PLL_4x | COM4_RESERVED,
> > + .clkrc = CLKRC_DIV2 | CLKRC_RESERVED,
> > + },
> > + [OV772X_FIN_48MHz] = {
> > + .com4 = PLL_BYPASS | COM4_RESERVED,
> > + .clkrc = CLKRC_BYPASS | CLKRC_RESERVED,
> > + },
> > + },
> > + },
> > +};
> > +
> > +static const struct ov772x_frame_rate qvga_frame_rates[] = {
> > + { /* PCLK = 3,2 MHz */
> > + .fps = 10,
> > + .pclk = {
> > + [OV772X_FIN_10MHz] = {
> > + .com4 = PLL_6x | COM4_RESERVED,
> > + .clkrc = CLKRC_DIV16 | CLKRC_RESERVED,
> > + },
> > + [OV772X_FIN_24MHz] = {
> > + .com4 = PLL_BYPASS | COM4_RESERVED,
> > + .clkrc = CLKRC_DIV8 | CLKRC_RESERVED,
> > + },
> > + [OV772X_FIN_48MHz] = {
> > + .com4 = PLL_BYPASS | COM4_RESERVED,
> > + .clkrc = CLKRC_DIV16 | CLKRC_RESERVED,
> > + },
> > + },
> > + },
> > + { /* PCLK = 4,8 MHz */
> > + .fps = 15,
> > + .pclk = {
> > + [OV772X_FIN_10MHz] = {
> > + .com4 = PLL_BYPASS | COM4_RESERVED,
> > + .clkrc = CLKRC_DIV2 | CLKRC_RESERVED,
> > + },
> > + [OV772X_FIN_24MHz] = {
> > + .com4 = PLL_BYPASS | COM4_RESERVED,
> > + .clkrc = CLKRC_DIV5 | CLKRC_RESERVED,
> > + },
> > + [OV772X_FIN_48MHz] = {
> > + .com4 = PLL_BYPASS | COM4_RESERVED,
> > + .clkrc = CLKRC_DIV10 | CLKRC_RESERVED,
> > + },
> > + },
> > + },
> > + { /* PCLK = 9,6 MHz */
> > + .fps = 30,
> > + .pclk = {
> > + [OV772X_FIN_10MHz] = {
> > + .com4 = PLL_BYPASS | COM4_RESERVED,
> > + .clkrc = CLKRC_BYPASS | CLKRC_RESERVED,
> > + },
> > + [OV772X_FIN_24MHz] = {
> > + .com4 = PLL_4x | COM4_RESERVED,
> > + .clkrc = CLKRC_DIV10 | CLKRC_RESERVED,
> > + },
> > + [OV772X_FIN_48MHz] = {
> > + .com4 = PLL_4x | COM4_RESERVED,
> > + .clkrc = CLKRC_DIV20 | CLKRC_RESERVED,
> > + },
> > + },
> > + },
> > + { /* PCLK = 19 MHz */
> > + .fps = 60,
> > + .pclk = {
> > + [OV772X_FIN_10MHz] = {
> > + .com4 = PLL_4x | COM4_RESERVED,
> > + .clkrc = CLKRC_DIV2 | CLKRC_RESERVED,
> > + },
> > + [OV772X_FIN_24MHz] = {
> > + .com4 = PLL_6x | COM4_RESERVED,
> > + .clkrc = CLKRC_DIV8 | CLKRC_RESERVED,
> > + },
> > + [OV772X_FIN_48MHz] = {
> > + .com4 = PLL_6x | COM4_RESERVED,
> > + .clkrc = CLKRC_DIV16 | CLKRC_RESERVED,
> > + },
> > + },
> > + },
> > +};
> > +
> > +/*
> > * general function
> > */
>
> I'm afraid I'll have to ask the obvious: could we replace this table with
> dynamic computation ? You might be able to reuse the (probably badly named)
> aptina-pll library from drivers/media/i2c/
>

Mmmm, okay... I might be able to use the above mentioned library,
but that's designed for a still simple but more complex PLL with 2
dividers and one multiplier. I know I can model it to work on ov7720
PLL using limits, but since I only have 4 possible PLL multipliers
(1x, 2x, 4x, 8x) and a single divider it is simpler to test all 4 of
them and see which one approximate the desired pixel clock.

I will send v8 with this changed shortly.

Thanks
j