diff options
Diffstat (limited to 'drivers/gpu/drm/sun4i/sun4i_hdmi_enc.c')
| -rw-r--r-- | drivers/gpu/drm/sun4i/sun4i_hdmi_enc.c | 20 |
1 files changed, 20 insertions, 0 deletions
diff --git a/drivers/gpu/drm/sun4i/sun4i_hdmi_enc.c b/drivers/gpu/drm/sun4i/sun4i_hdmi_enc.c index dda904ec0534..500b6fb3e028 100644 --- a/drivers/gpu/drm/sun4i/sun4i_hdmi_enc.c +++ b/drivers/gpu/drm/sun4i/sun4i_hdmi_enc.c @@ -175,11 +175,31 @@ static void sun4i_hdmi_mode_set(struct drm_encoder *encoder, writel(val, hdmi->base + SUN4I_HDMI_VID_TIMING_POL_REG); } +static enum drm_mode_status sun4i_hdmi_mode_valid(struct drm_encoder *encoder, + const struct drm_display_mode *mode) +{ + struct sun4i_hdmi *hdmi = drm_encoder_to_sun4i_hdmi(encoder); + unsigned long rate = mode->clock * 1000; + unsigned long diff = rate / 200; /* +-0.5% allowed by HDMI spec */ + long rounded_rate; + + /* 165 MHz is the typical max pixelclock frequency for HDMI <= 1.2 */ + if (rate > 165000000) + return MODE_CLOCK_HIGH; + rounded_rate = clk_round_rate(hdmi->tmds_clk, rate); + if (rounded_rate > 0 && + max_t(unsigned long, rounded_rate, rate) - + min_t(unsigned long, rounded_rate, rate) < diff) + return MODE_OK; + return MODE_NOCLOCK; +} + static const struct drm_encoder_helper_funcs sun4i_hdmi_helper_funcs = { .atomic_check = sun4i_hdmi_atomic_check, .disable = sun4i_hdmi_disable, .enable = sun4i_hdmi_enable, .mode_set = sun4i_hdmi_mode_set, + .mode_valid = sun4i_hdmi_mode_valid, }; static const struct drm_encoder_funcs sun4i_hdmi_funcs = { |