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drm/dp: add DP 2.0 UHBR link rate and bw code conversions

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The bw code equals link_rate / 0.27 Gbps only for 8b/10b link
rates. Handle DP 2.0 UHBR rates as special cases, though this is not
pretty.

Cc: dri-devel@lists.freedesktop.org
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Acked-by: Maxime Ripard <mripard@kernel.org>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/cab4edda8834d6b4db610fabb5e1f1f18ae33c2c.1631191763.git.jani.nikula@intel.com
This commit is contained in:
Jani Nikula 2021-09-09 15:51:53 +03:00
parent 641dd82ffa
commit 054ce0bce2
1 changed files with 22 additions and 4 deletions
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26
drivers/gpu/drm/drm_dp_helper.c
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@ -207,15 +207,33 @@ EXPORT_SYMBOL(drm_dp_lttpr_link_train_channel_eq_delay);
u8 drm_dp_link_rate_to_bw_code(int link_rate)
{
/* Spec says link_bw = link_rate / 0.27Gbps */
return link_rate / 27000;
switch (link_rate) {
case 1000000:
return DP_LINK_BW_10;
case 1350000:
return DP_LINK_BW_13_5;
case 2000000:
return DP_LINK_BW_20;
default:
/* Spec says link_bw = link_rate / 0.27Gbps */
return link_rate / 27000;
}
}
EXPORT_SYMBOL(drm_dp_link_rate_to_bw_code);
int drm_dp_bw_code_to_link_rate(u8 link_bw)
{
/* Spec says link_rate = link_bw * 0.27Gbps */
return link_bw * 27000;
switch (link_bw) {
case DP_LINK_BW_10:
return 1000000;
case DP_LINK_BW_13_5:
return 1350000;
case DP_LINK_BW_20:
return 2000000;
default:
/* Spec says link_rate = link_bw * 0.27Gbps */
return link_bw * 27000;
}
}
EXPORT_SYMBOL(drm_dp_bw_code_to_link_rate);