diff options
Diffstat (limited to 'drivers/gpu/drm/drm_dp_helper.c')
| -rw-r--r-- | drivers/gpu/drm/drm_dp_helper.c | 31 |
1 files changed, 31 insertions, 0 deletions
diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c index 79968e39c8d0..f1283878ff6d 100644 --- a/drivers/gpu/drm/drm_dp_helper.c +++ b/drivers/gpu/drm/drm_dp_helper.c @@ -354,6 +354,37 @@ int drm_dp_link_power_up(struct drm_dp_aux *aux, struct drm_dp_link *link) EXPORT_SYMBOL(drm_dp_link_power_up); /** + * drm_dp_link_power_down() - power down a DisplayPort link + * @aux: DisplayPort AUX channel + * @link: pointer to a structure containing the link configuration + * + * Returns 0 on success or a negative error code on failure. + */ +int drm_dp_link_power_down(struct drm_dp_aux *aux, struct drm_dp_link *link) +{ + u8 value; + int err; + + /* DP_SET_POWER register is only available on DPCD v1.1 and later */ + if (link->revision < 0x11) + return 0; + + err = drm_dp_dpcd_readb(aux, DP_SET_POWER, &value); + if (err < 0) + return err; + + value &= ~DP_SET_POWER_MASK; + value |= DP_SET_POWER_D3; + + err = drm_dp_dpcd_writeb(aux, DP_SET_POWER, value); + if (err < 0) + return err; + + return 0; +} +EXPORT_SYMBOL(drm_dp_link_power_down); + +/** * drm_dp_link_configure() - configure a DisplayPort link * @aux: DisplayPort AUX channel * @link: pointer to a structure containing the link configuration |