From 399d9f2f197a06b8866192a019a97d2af29cc81e Mon Sep 17 00:00:00 2001 From: Laurent Pinchart Date: Wed, 22 Aug 2018 17:04:06 +0300 Subject: drm: bridge: thc63: Restrict modes based on hardware operating frequency The THC63LVD1024 is restricted to a pixel clock frequency in the range of 8 to 135 MHz. Implement the bridge .mode_valid() operation accordingly. Signed-off-by: Laurent Pinchart Reviewed-by: Andrzej Hajda Tested-by: Jacopo Mondi --- drivers/gpu/drm/bridge/thc63lvd1024.c | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) (limited to 'drivers/gpu/drm/bridge') diff --git a/drivers/gpu/drm/bridge/thc63lvd1024.c b/drivers/gpu/drm/bridge/thc63lvd1024.c index c8b9edd5a7f4..b083a740565c 100644 --- a/drivers/gpu/drm/bridge/thc63lvd1024.c +++ b/drivers/gpu/drm/bridge/thc63lvd1024.c @@ -45,6 +45,23 @@ static int thc63_attach(struct drm_bridge *bridge) return drm_bridge_attach(bridge->encoder, thc63->next, bridge); } +static enum drm_mode_status thc63_mode_valid(struct drm_bridge *bridge, + const struct drm_display_mode *mode) +{ + /* + * The THC63LVD1024 clock frequency range is 8 to 135 MHz in single-in + * mode. Note that the limits are different in dual-in, single-out mode, + * and will need to be adjusted accordingly. + */ + if (mode->clock < 8000) + return MODE_CLOCK_LOW; + + if (mode->clock > 135000) + return MODE_CLOCK_HIGH; + + return MODE_OK; +} + static void thc63_enable(struct drm_bridge *bridge) { struct thc63_dev *thc63 = to_thc63(bridge); @@ -77,6 +94,7 @@ static void thc63_disable(struct drm_bridge *bridge) static const struct drm_bridge_funcs thc63_bridge_func = { .attach = thc63_attach, + .mode_valid = thc63_mode_valid, .enable = thc63_enable, .disable = thc63_disable, }; -- cgit