[Intel-gfx] [PATCH] drm/i915/mtl: Add new vswing table for C20 phy to support DP 1.4

[Sripada, Radhakrishna]

Hi Shawn,

> -----Original Message-----
> From: Lee, Shawn C <shawn.c.lee at intel.com>
> Sent: Tuesday, June 6, 2023 3:43 AM
> To: intel-gfx at lists.freedesktop.org
> Cc: Lee, Shawn C <shawn.c.lee at intel.com>; Kahola, Mika
> <mika.kahola at intel.com>; Taylor, Clinton A <clinton.a.taylor at intel.com>;
> Sripada, Radhakrishna <radhakrishna.sripada at intel.com>; Shankar, Uma
> <uma.shankar at intel.com>
> Subject: [PATCH] drm/i915/mtl: Add new vswing table for C20 phy to support DP
> 1.4
> 
> Add vswing table to support DP 1.4 for C20 phy.
> 
> Bspec: 74104
> Signed-off-by: Lee Shawn C <shawn.c.lee at intel.com>
> Cc: Mika Kahola <mika.kahola at intel.com>
> Cc: Clint Taylor <Clinton.A.Taylor at intel.com>
> Cc: Radhakrishna Sripada <radhakrishna.sripada at intel.com>
> Cc: Uma Shankar <uma.shankar at intel.com>
> ---
>  .../drm/i915/display/intel_ddi_buf_trans.c    | 21 +++++++++++++++++++
>  1 file changed, 21 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_ddi_buf_trans.c
> b/drivers/gpu/drm/i915/display/intel_ddi_buf_trans.c
> index b7d20485bde5..6a1507515119 100644
> --- a/drivers/gpu/drm/i915/display/intel_ddi_buf_trans.c
> +++ b/drivers/gpu/drm/i915/display/intel_ddi_buf_trans.c
> @@ -1055,6 +1055,20 @@ static const struct intel_ddi_buf_trans mtl_cx0_trans
> = {
>  	.hdmi_default_entry = ARRAY_SIZE(_mtl_c10_trans_dp14) - 1,
>  };
> 
> +/* DP1.4 */
> +static const union intel_ddi_buf_trans_entry _mtl_c20_trans_dp14[] = {
> +	{ .snps = { 20, 0, 0  } },      /* preset 0 */
> +	{ .snps = { 24, 0, 4  } },      /* preset 1 */
> +	{ .snps = { 30, 0, 9  } },      /* preset 2 */
> +	{ .snps = { 34, 0, 14 } },      /* preset 3 */
> +	{ .snps = { 29, 0, 0  } },      /* preset 4 */
> +	{ .snps = { 34, 0, 5  } },      /* preset 5 */
> +	{ .snps = { 38, 0, 10 } },      /* preset 6 */
> +	{ .snps = { 36, 0, 0  } },      /* preset 7 */
> +	{ .snps = { 40, 0, 6  } },      /* preset 8 */
> +	{ .snps = { 48, 0, 0  } },      /* preset 9 */
> +};
> +
>  /* DP2.0 */
>  static const union intel_ddi_buf_trans_entry _mtl_c20_trans_uhbr[] = {
>  	{ .snps = { 48, 0, 0 } },       /* preset 0 */
> @@ -1090,6 +1104,11 @@ static const struct intel_ddi_buf_trans
> mtl_c20_trans_hdmi = {
>  	.hdmi_default_entry = 0,
>  };
> 
> +static const struct intel_ddi_buf_trans mtl_c20_trans_dp14 = {
> +	.entries = _mtl_c20_trans_dp14,
> +	.num_entries = ARRAY_SIZE(_mtl_c20_trans_dp14),
> +};
> +
>  static const struct intel_ddi_buf_trans mtl_c20_trans_uhbr = {
>  	.entries = _mtl_c20_trans_uhbr,
>  	.num_entries = ARRAY_SIZE(_mtl_c20_trans_uhbr),
> @@ -1678,6 +1697,8 @@ mtl_get_cx0_buf_trans(struct intel_encoder
> *encoder,
>  		return intel_get_buf_trans(&mtl_c20_trans_uhbr, n_entries);
>  	else if (intel_crtc_has_type(crtc_state, INTEL_OUTPUT_HDMI) &&
> !(intel_is_c10phy(i915, phy)))
>  		return intel_get_buf_trans(&mtl_c20_trans_hdmi, n_entries);
> +	else if (!intel_is_c10phy(i915, phy))
> +		return intel_get_buf_trans(&mtl_c20_trans_dp14, n_entries);
>  	else
>  		return intel_get_buf_trans(&mtl_cx0_trans, n_entries);
Nit: With mtl_c20_trans_dp14, mtl_cx0_trans looses its meaning and needs to be renamed
As mtl_c10_trans or even better mtl_trans_dp14 for the sake of consistency.

With that,
Reviewed-by: Radhakrishna Sripada <radhakrishna.sripada at intel.com>

--Radhakrishna(RK) Sripada
>  }
> --
> 2.31.1