Re: [PATCH v4 11/11] media: ccs-pll: Document the CCS PLL flags

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

On Wed, Apr 23, 2025 at 06:37:19PM +0300, Sakari Ailus wrote:
> Document the CCS PLL flags with short comments. The CCS spec has more
> information on them while the added documentation helps finding the
> relevant information in the CCS spec.
> 
> Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
> ---
> since v3:
> 
> - Refer to pixels in CCS_PLL_FLAG_OP_PIX_DDR comment.

Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

>  drivers/media/i2c/ccs-pll.c |  2 +-
>  drivers/media/i2c/ccs-pll.h | 27 ++++++++++++++++++++++++---
>  2 files changed, 25 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/media/i2c/ccs-pll.c b/drivers/media/i2c/ccs-pll.c
> index 87798616b76d..8f9a695bd9e5 100644
> --- a/drivers/media/i2c/ccs-pll.c
> +++ b/drivers/media/i2c/ccs-pll.c
> @@ -129,8 +129,8 @@ static void print_pll_flags(struct device *dev, struct ccs_pll *pll)
>  {
>  	dev_dbg(dev, "PLL flags%s%s%s%s%s%s%s%s%s%s%s\n",
>  		pll->flags & PLL_FL(OP_PIX_CLOCK_PER_LANE) ? " op-pix-clock-per-lane" : "",
> -		pll->flags & PLL_FL(NO_OP_CLOCKS) ? " no-op-clocks" : "",
>  		pll->flags & PLL_FL(EVEN_PLL_MULTIPLIER) ? " even-pll-multiplier" : "",
> +		pll->flags & PLL_FL(NO_OP_CLOCKS) ? " no-op-clocks" : "",
>  		pll->flags & PLL_FL(LANE_SPEED_MODEL) ? " lane-speed" : "",
>  		pll->flags & PLL_FL(EXT_IP_PLL_DIVIDER) ?
>  		" ext-ip-pll-divider" : "",
> diff --git a/drivers/media/i2c/ccs-pll.h b/drivers/media/i2c/ccs-pll.h
> index 754eb5f52cc4..e22903931e72 100644
> --- a/drivers/media/i2c/ccs-pll.h
> +++ b/drivers/media/i2c/ccs-pll.h
> @@ -18,19 +18,40 @@
>  #define CCS_PLL_BUS_TYPE_CSI2_DPHY				0x00
>  #define CCS_PLL_BUS_TYPE_CSI2_CPHY				0x01
>  
> -/* Old SMIA and implementation specific flags */
> -/* op pix clock is for all lanes in total normally */
> +/* Old SMIA and implementation specific flags. */
> +/* OP PIX clock is for all lanes in total normally. */
>  #define CCS_PLL_FLAG_OP_PIX_CLOCK_PER_LANE			BIT(0)
> -#define CCS_PLL_FLAG_NO_OP_CLOCKS				BIT(1)
> +/* If set, the PLL multipliers are required to be even. */
>  #define CCS_PLL_FLAG_EVEN_PLL_MULTIPLIER			BIT(3)
> +
>  /* CCS PLL flags */
> +
> +/* The sensor doesn't have OP clocks at all. */
> +#define CCS_PLL_FLAG_NO_OP_CLOCKS				BIT(1)
> +/* System speed model if this flag is unset. */
>  #define CCS_PLL_FLAG_LANE_SPEED_MODEL				BIT(2)
> +/* If set, the pre-PLL divider may have odd values, too. */
>  #define CCS_PLL_FLAG_EXT_IP_PLL_DIVIDER				BIT(4)
> +/*
> + * If set, the OP PIX clock doesn't have to exactly match with data rate, it may
> + * be higher. See "OP Domain Formulas" in MIPI CCS 1.1 spec.
> + */
>  #define CCS_PLL_FLAG_FLEXIBLE_OP_PIX_CLK_DIV			BIT(5)
> +/* If set, the VT domain may run faster than the OP domain. */
>  #define CCS_PLL_FLAG_FIFO_DERATING				BIT(6)
> +/* If set, the VT domain may run slower than the OP domain. */
>  #define CCS_PLL_FLAG_FIFO_OVERRATING				BIT(7)
> +/* If set, the PLL tree has two PLLs instead of one. */
>  #define CCS_PLL_FLAG_DUAL_PLL					BIT(8)
> +/*
> + * If set, the OP SYS clock is a dual data rate clock, transferring two bits per
> + * cycle instead of one.
> + */
>  #define CCS_PLL_FLAG_OP_SYS_DDR					BIT(9)
> +/*
> + * If set, the OP PIX clock is a dual data rate clock, transferring two pixels
> + * per cycle instead of one.
> + */
>  #define CCS_PLL_FLAG_OP_PIX_DDR					BIT(10)
>  
>  /**

-- 
Regards,

Laurent Pinchart