drm/meson: dw_hdmi: Add support for an optional external 5V regulator

On reference boards and derivatives, the HDMI Logic is powered by an external
5V regulator.
This regulator was set by the Vendor U-Boot, add optional support for it.

Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Tested-by: Jerome Brunet <jbrunet@baylibre.com>
Reviewed-by: Jerome Brunet <jbrunet@baylibre.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1512561268-29806-4-git-send-email-narmstrong@baylibre.com

diff --git a/drivers/gpu/drm/meson/meson_dw_hdmi.c b/drivers/gpu/drm/meson/meson_dw_hdmi.c
index cef4144..17de3af 100644 (file)
--- a/drivers/gpu/drm/meson/meson_dw_hdmi.c
+++ b/drivers/gpu/drm/meson/meson_dw_hdmi.c
@@ -23,6 +23,7 @@
 #include <linux/of_graph.h>
 #include <linux/reset.h>
 #include <linux/clk.h>
+#include <linux/regulator/consumer.h>
 
 #include <drm/drmP.h>
 #include <drm/drm_edid.h>
@@ -137,6 +138,7 @@ struct meson_dw_hdmi {
        struct reset_control *hdmitx_phy;
        struct clk *hdmi_pclk;
        struct clk *venci_clk;
+       struct regulator *hdmi_supply;
        u32 irq_stat;
 };
 #define encoder_to_meson_dw_hdmi(x) \
@@ -751,6 +753,17 @@ static int meson_dw_hdmi_bind(struct device *dev, struct device *master,
        dw_plat_data = &meson_dw_hdmi->dw_plat_data;
        encoder = &meson_dw_hdmi->encoder;
 
+       meson_dw_hdmi->hdmi_supply = devm_regulator_get_optional(dev, "hdmi");
+       if (IS_ERR(meson_dw_hdmi->hdmi_supply)) {
+               if (PTR_ERR(meson_dw_hdmi->hdmi_supply) == -EPROBE_DEFER)
+                       return -EPROBE_DEFER;
+               meson_dw_hdmi->hdmi_supply = NULL;
+       } else {
+               ret = regulator_enable(meson_dw_hdmi->hdmi_supply);
+               if (ret)
+                       return ret;
+       }
+
        meson_dw_hdmi->hdmitx_apb = devm_reset_control_get_exclusive(dev,
                                                "hdmitx_apb");
        if (IS_ERR(meson_dw_hdmi->hdmitx_apb)) {