Hi,

The prefix of your title should be "drm/sun4i: tcon:" instead of "ARM:
sun7i:"

The latter would be if you were modifying files under arch/arm, but
you're modifying files in (drivers/gpu/)drm/sun4i :)

On Thu, Feb 13, 2020 at 12:23:55AM +0200, andrey.lebedev@gmail.com wrote:
> From: Andrey Lebedev <andrey@lebedev.lt>
>
> A20 SoC (found in Cubieboard 2 among others) requires different LVDS set
> up procedure than A33. Timing controller (tcon) driver only implements
> sun6i-style procedure, that doesn't work on A20 (sun7i).
>
> Signed-off-by: Andrey Lebedev <andrey@lebedev.lt>
> ---
>  drivers/gpu/drm/sun4i/sun4i_tcon.c | 95 ++++++++++++++++++++----------
>  drivers/gpu/drm/sun4i/sun4i_tcon.h | 14 +++++
>  2 files changed, 77 insertions(+), 32 deletions(-)
>
> diff --git a/drivers/gpu/drm/sun4i/sun4i_tcon.c b/drivers/gpu/drm/sun4i/sun4i_tcon.c
> index c81cdce6ed55..e4c605ca685e 100644
> --- a/drivers/gpu/drm/sun4i/sun4i_tcon.c
> +++ b/drivers/gpu/drm/sun4i/sun4i_tcon.c
> @@ -114,46 +114,73 @@ static void sun4i_tcon_channel_set_status(struct sun4i_tcon *tcon, int channel,
>  	}
>  }
>
> +static void sun6i_tcon_setup_lvds_phy(struct sun4i_tcon *tcon,
> +				      const struct drm_encoder *encoder)
> +{
> +	u8 val;
> +
> +	regmap_write(tcon->regs, SUN4I_TCON0_LVDS_ANA0_REG,
> +		     SUN6I_TCON0_LVDS_ANA0_C(2) |
> +		     SUN6I_TCON0_LVDS_ANA0_V(3) |
> +		     SUN6I_TCON0_LVDS_ANA0_PD(2) |
> +		     SUN6I_TCON0_LVDS_ANA0_EN_LDO);
> +	udelay(2);
> +
> +	regmap_update_bits(tcon->regs, SUN4I_TCON0_LVDS_ANA0_REG,
> +			   SUN6I_TCON0_LVDS_ANA0_EN_MB,
> +			   SUN6I_TCON0_LVDS_ANA0_EN_MB);
> +	udelay(2);
> +
> +	regmap_update_bits(tcon->regs, SUN4I_TCON0_LVDS_ANA0_REG,
> +			   SUN6I_TCON0_LVDS_ANA0_EN_DRVC,
> +			   SUN6I_TCON0_LVDS_ANA0_EN_DRVC);
> +
> +	if (sun4i_tcon_get_pixel_depth(encoder) == 18)
> +		val = 7;
> +	else
> +		val = 0xf;
> +
> +	regmap_write_bits(tcon->regs, SUN4I_TCON0_LVDS_ANA0_REG,
> +			  SUN6I_TCON0_LVDS_ANA0_EN_DRVD(0xf),
> +			  SUN6I_TCON0_LVDS_ANA0_EN_DRVD(val));
> +
> +}
> +
> +static void sun4i_tcon_setup_lvds_phy(struct sun4i_tcon *tcon,
> +				      const struct drm_encoder *encoder)
> +{
> +	regmap_write(tcon->regs, SUN4I_TCON0_LVDS_ANA0_REG,
> +		     SUN4I_TCON0_LVDS_ANA0_CK_EN |
> +		     SUN4I_TCON0_LVDS_ANA0_REG_V |
> +		     SUN4I_TCON0_LVDS_ANA0_REG_C |
> +		     SUN4I_TCON0_LVDS_ANA0_EN_MB |
> +		     SUN4I_TCON0_LVDS_ANA0_PD |
> +		     SUN4I_TCON0_LVDS_ANA0_DCHS);
> +
> +	udelay(2); /* delay at least 1200 ns */
> +	regmap_update_bits(tcon->regs, SUN4I_TCON0_LVDS_ANA1_REG,
> +			   SUN4I_TCON0_LVDS_ANA1_INIT,
> +			   SUN4I_TCON0_LVDS_ANA1_INIT);
> +	udelay(1); /* delay at least 120 ns */
> +	regmap_update_bits(tcon->regs, SUN4I_TCON0_LVDS_ANA1_REG,
> +			   SUN4I_TCON0_LVDS_ANA1_UPDATE,
> +			   SUN4I_TCON0_LVDS_ANA1_UPDATE);
> +	regmap_update_bits(tcon->regs, SUN4I_TCON0_LVDS_ANA0_REG,
> +			   SUN4I_TCON0_LVDS_ANA0_EN_MB,
> +			   SUN4I_TCON0_LVDS_ANA0_EN_MB);
> +}
> +
> +

Patches should contain only one logical change, so ideally this should
be two patches: one to create the function pointer and fill it for the
A31 style setup, the other one to add support for the A20.

Also, you should have only a single line between the two functions and
the second should come before the first (alphabetical ordering).

Maxime