diff options
| author | Alexander Stein <alexander.stein@ew.tq-group.com> | 2022-12-08 09:55:38 +0300 |
|---|---|---|
| committer | Neil Armstrong <neil.armstrong@linaro.org> | 2023-01-19 10:50:50 +0300 |
| commit | bd43a9844bc6f78e00fdc91db47f6969d10c5ac5 (patch) | |
| tree | 5c5d2c51de61a30e484536711cb5b7948793d5c6 | |
| parent | ae5a8dce3c86c1ea8e17910c3836b92a406f9ad8 (diff) | |
| download | linux-bd43a9844bc6f78e00fdc91db47f6969d10c5ac5.tar.xz | |
drm: bridge: ldb: Warn if LDB clock does not match requested link frequency
The LDB clock needs to be exactly 7-times the pixel clock used by the
display.
Signed-off-by: Alexander Stein <alexander.stein@ew.tq-group.com>
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20221208065538.1753666-1-alexander.stein@ew.tq-group.com
| -rw-r--r-- | drivers/gpu/drm/bridge/fsl-ldb.c | 23 |
1 files changed, 19 insertions, 4 deletions
diff --git a/drivers/gpu/drm/bridge/fsl-ldb.c b/drivers/gpu/drm/bridge/fsl-ldb.c index f9e0f8d99268..9bcba8fc57e7 100644 --- a/drivers/gpu/drm/bridge/fsl-ldb.c +++ b/drivers/gpu/drm/bridge/fsl-ldb.c @@ -66,6 +66,14 @@ static inline struct fsl_ldb *to_fsl_ldb(struct drm_bridge *bridge) return container_of(bridge, struct fsl_ldb, bridge); } +static unsigned long fsl_ldb_link_frequency(struct fsl_ldb *fsl_ldb, int clock) +{ + if (fsl_ldb->lvds_dual_link) + return clock * 3500; + else + return clock * 7000; +} + static int fsl_ldb_attach(struct drm_bridge *bridge, enum drm_bridge_attach_flags flags) { @@ -85,6 +93,8 @@ static void fsl_ldb_atomic_enable(struct drm_bridge *bridge, const struct drm_display_mode *mode; struct drm_connector *connector; struct drm_crtc *crtc; + unsigned long configured_link_freq; + unsigned long requested_link_freq; bool lvds_format_24bpp; bool lvds_format_jeida; u32 reg; @@ -128,10 +138,15 @@ static void fsl_ldb_atomic_enable(struct drm_bridge *bridge, crtc_state = drm_atomic_get_new_crtc_state(state, crtc); mode = &crtc_state->adjusted_mode; - if (fsl_ldb->lvds_dual_link) - clk_set_rate(fsl_ldb->clk, mode->clock * 3500); - else - clk_set_rate(fsl_ldb->clk, mode->clock * 7000); + requested_link_freq = fsl_ldb_link_frequency(fsl_ldb, mode->clock); + clk_set_rate(fsl_ldb->clk, requested_link_freq); + + configured_link_freq = clk_get_rate(fsl_ldb->clk); + if (configured_link_freq != requested_link_freq) + dev_warn(fsl_ldb->dev, "Configured LDB clock (%lu Hz) does not match requested LVDS clock: %lu Hz", + configured_link_freq, + requested_link_freq); + clk_prepare_enable(fsl_ldb->clk); /* Program LDB_CTRL */ |