Re: [PATCH 1/3] drm: rcar-du: lvds: refactor LVDS startup

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

Hi Sergei,

Thank you for the patch.

On Thursday, 11 January 2018 18:54:33 EET Sergei Shtylyov wrote:
> After the recent correction of the R-Car gen3 LVDCR1 value, already similar
> enough at their  ends rcar_du_lvdsenc_start_gen{2|3}() started asking for a
> merge and it's becoming actually necessary with the addition the R-Car V3M
> (R8A77970) support -- this  gen3 SoC  has gen2-like LVDPLLCR layout.
> 
> BTW, such a merge saves 72 bytes of the object code with AArch64 gcc 4.8.5.
> 
> Signed-off-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
> 
> ---
>  drivers/gpu/drm/rcar-du/rcar_du_lvdsenc.c |  132 +++++++++++---------------
>  1 file changed, 54 insertions(+), 78 deletions(-)
> 
> Index: linux/drivers/gpu/drm/rcar-du/rcar_du_lvdsenc.c
> ===================================================================
> --- linux.orig/drivers/gpu/drm/rcar-du/rcar_du_lvdsenc.c
> +++ linux/drivers/gpu/drm/rcar-du/rcar_du_lvdsenc.c
> @@ -39,98 +39,41 @@ static void rcar_lvds_write(struct rcar_
>  	iowrite32(data, lvds->mmio + reg);
>  }
> 
> -static void rcar_du_lvdsenc_start_gen2(struct rcar_du_lvdsenc *lvds,
> -				       struct rcar_du_crtc *rcrtc)
> +static u32 rcar_lvds_gen2_lvdpllcr(unsigned int freq)
>  {
> -	const struct drm_display_mode *mode = &rcrtc->crtc.mode;
> -	unsigned int freq = mode->clock;
> -	u32 lvdcr0;
> -	u32 pllcr;
> +	u32 lvdpllcr;
> 
> -	/* PLL clock configuration */
>  	if (freq < 39000)
> -		pllcr = LVDPLLCR_CEEN | LVDPLLCR_COSEL | LVDPLLCR_PLLDLYCNT_38M;
> +		lvdpllcr = LVDPLLCR_PLLDLYCNT_38M;
>  	else if (freq < 61000)
> -		pllcr = LVDPLLCR_CEEN | LVDPLLCR_COSEL | LVDPLLCR_PLLDLYCNT_60M;
> +		lvdpllcr = LVDPLLCR_PLLDLYCNT_60M;
>  	else if (freq < 121000)
> -		pllcr = LVDPLLCR_CEEN | LVDPLLCR_COSEL | LVDPLLCR_PLLDLYCNT_121M;
> +		lvdpllcr = LVDPLLCR_PLLDLYCNT_121M;
>  	else
> -		pllcr = LVDPLLCR_PLLDLYCNT_150M;
> -
> -	rcar_lvds_write(lvds, LVDPLLCR, pllcr);
> -
> -	/*
> -	 * Select the input, hardcode mode 0, enable LVDS operation and turn
> -	 * bias circuitry on.
> -	 */
> -	lvdcr0 = (lvds->mode << LVDCR0_LVMD_SHIFT) | LVDCR0_BEN | LVDCR0_LVEN;
> -	if (rcrtc->index == 2)
> -		lvdcr0 |= LVDCR0_DUSEL;
> -	rcar_lvds_write(lvds, LVDCR0, lvdcr0);
> +		return LVDPLLCR_PLLDLYCNT_150M;
> 
> -	/* Turn all the channels on. */
> -	rcar_lvds_write(lvds, LVDCR1,
> -			LVDCR1_CHSTBY(3) | LVDCR1_CHSTBY(2) |
> -			LVDCR1_CHSTBY(1) | LVDCR1_CHSTBY(0) | LVDCR1_CLKSTBY);
> -
> -	/*
> -	 * Turn the PLL on, wait for the startup delay, and turn the output
> -	 * on.
> -	 */
> -	lvdcr0 |= LVDCR0_PLLON;
> -	rcar_lvds_write(lvds, LVDCR0, lvdcr0);
> -
> -	usleep_range(100, 150);
> -
> -	lvdcr0 |= LVDCR0_LVRES;
> -	rcar_lvds_write(lvds, LVDCR0, lvdcr0);
> +	return lvdpllcr | LVDPLLCR_CEEN | LVDPLLCR_COSEL;
>  }
> 
> -static void rcar_du_lvdsenc_start_gen3(struct rcar_du_lvdsenc *lvds,
> -				       struct rcar_du_crtc *rcrtc)
> +static u32 rcar_lvds_gen3_lvdpllcr(unsigned int freq)
>  {
> -	const struct drm_display_mode *mode = &rcrtc->crtc.mode;
> -	unsigned int freq = mode->clock;
> -	u32 lvdcr0;
> -	u32 pllcr;
> -
> -	/* PLL clock configuration */
>  	if (freq < 42000)
> -		pllcr = LVDPLLCR_PLLDIVCNT_42M;
> +		return LVDPLLCR_PLLDIVCNT_42M;
>  	else if (freq < 85000)
> -		pllcr = LVDPLLCR_PLLDIVCNT_85M;
> +		return LVDPLLCR_PLLDIVCNT_85M;
>  	else if (freq < 128000)
> -		pllcr = LVDPLLCR_PLLDIVCNT_128M;
> -	else
> -		pllcr = LVDPLLCR_PLLDIVCNT_148M;
> -
> -	rcar_lvds_write(lvds, LVDPLLCR, pllcr);
> -
> -	/* Turn all the channels on. */
> -	rcar_lvds_write(lvds, LVDCR1,
> -			LVDCR1_CHSTBY(3) | LVDCR1_CHSTBY(2) |
> -			LVDCR1_CHSTBY(1) | LVDCR1_CHSTBY(0) | LVDCR1_CLKSTBY);
> -
> -	/*
> -	 * Turn the PLL on, set it to LVDS normal mode, wait for the startup
> -	 * delay and turn the output on.
> -	 */
> -	lvdcr0 = (lvds->mode << LVDCR0_LVMD_SHIFT) | LVDCR0_PLLON;
> -	rcar_lvds_write(lvds, LVDCR0, lvdcr0);
> -
> -	lvdcr0 |= LVDCR0_PWD;
> -	rcar_lvds_write(lvds, LVDCR0, lvdcr0);
> +		return LVDPLLCR_PLLDIVCNT_128M;
> 
> -	usleep_range(100, 150);
> -
> -	lvdcr0 |= LVDCR0_LVRES;
> -	rcar_lvds_write(lvds, LVDCR0, lvdcr0);
> +	return LVDPLLCR_PLLDIVCNT_148M;
>  }
> 
>  static int rcar_du_lvdsenc_start(struct rcar_du_lvdsenc *lvds,
>  				 struct rcar_du_crtc *rcrtc)
>  {
> -	u32 lvdhcr;
> +	u32 lvdhcr, lvdpllcr, lvdcr0 = lvds->mode << LVDCR0_LVMD_SHIFT;

Please declare variables on separate lines. Especially having lvdcr0 on a line 
of its own will make it clearer.

> +	const struct drm_display_mode *mode = &rcrtc->crtc.mode;
> +	unsigned int gen = lvds->dev->info->gen;
> +	unsigned int freq = mode->clock;
>  	int ret;
> 
>  	if (lvds->enabled)
> @@ -158,14 +101,47 @@ static int rcar_du_lvdsenc_start(struct
>  	else
>  		lvdhcr = LVDCHCR_CHSEL_CH(0, 0) | LVDCHCR_CHSEL_CH(1, 1)
> 
>  		       | LVDCHCR_CHSEL_CH(2, 2) | LVDCHCR_CHSEL_CH(3, 3);
> 
> -
>  	rcar_lvds_write(lvds, LVDCHCR, lvdhcr);
> 
> -	/* Perform generation-specific initialization. */
> -	if (lvds->dev->info->gen < 3)
> -		rcar_du_lvdsenc_start_gen2(lvds, rcrtc);
> +	/* PLL clock configuration */
> +	if (gen < 3)
> +		lvdpllcr = rcar_lvds_gen2_lvdpllcr(freq);
>  	else
> -		rcar_du_lvdsenc_start_gen3(lvds, rcrtc);
> +		lvdpllcr = rcar_lvds_gen3_lvdpllcr(freq);
> +	rcar_lvds_write(lvds, LVDPLLCR,	lvdpllcr);
> +
> +	if (gen < 3) {
> +		/*
> +		 * Select the input, enable LVDS operation, and turn
> +		 * the bias circuitry on.
> +		 */
> +		lvdcr0 |= LVDCR0_BEN | LVDCR0_LVEN;
> +		if (rcrtc->index == 2)
> +			lvdcr0 |= LVDCR0_DUSEL;
> +		rcar_lvds_write(lvds, LVDCR0, lvdcr0);
> +	}
> +
> +	/* Turn all the channels on. */
> +	rcar_lvds_write(lvds, LVDCR1,
> +			LVDCR1_CHSTBY(3) | LVDCR1_CHSTBY(2) |
> +			LVDCR1_CHSTBY(1) | LVDCR1_CHSTBY(0) | LVDCR1_CLKSTBY);
> +
> +	/* Turn the PLL on. */
> +	lvdcr0 |= LVDCR0_PLLON;
> +	rcar_lvds_write(lvds, LVDCR0, lvdcr0);
> +
> +	if (gen > 2) {
> +		/* Turn on the LVDS normal mode. */
> +		lvdcr0 |= LVDCR0_PWD;
> +		rcar_lvds_write(lvds, LVDCR0, lvdcr0);
> +	}
> +
> +	/* Wait for the startup delay. */
> +	usleep_range(100, 150);
> +
> +	/* Turn the output on. */
> +	lvdcr0 |= LVDCR0_LVRES;
> +	rcar_lvds_write(lvds, LVDCR0, lvdcr0);
> 
>  	lvds->enabled = true;

How will this work with the D3 and E3 SoCs ? They seem to have a few 
differences, will code still be reusable ?

-- 
Regards,

Laurent Pinchart