[PATCH] drm/hisilicon: add the mode_valid function

[Tian Tao]

add mode_valid function, and we can also use it to make suse the resolution
is valid.

Signed-off-by: Tian Tao <tiantao6 at hisilicon.com>
Signed-off-by: Gong junjie <gongjunjie2 at huawei.com>
---
 drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_de.c | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_de.c b/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_de.c
index 843d784..6cb7a79 100644
--- a/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_de.c
+++ b/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_de.c
@@ -242,6 +242,25 @@ static void hibmc_crtc_atomic_disable(struct drm_crtc *crtc,
 	hibmc_set_current_gate(priv, reg);
 }
 
+enum drm_mode_status hibmc_crtc_mode_valid(struct drm_crtc *crtc,
+					const struct drm_display_mode *mode)
+{
+	int i = 0;
+	int vrefresh = drm_mode_vrefresh(mode);
+
+	if (vrefresh < 59 || vrefresh > 61)
+		return MODE_NOMODE;
+
+	for (i = 0; i < ARRAY_SIZE(hibmc_pll_table); i++) {
+		if (hibmc_pll_table[i].hdisplay == mode->hdisplay &&
+			hibmc_pll_table[i].vdisplay == mode->vdisplay)
+			return MODE_OK;
+	}
+
+	return MODE_NOMODE;
+}
+
+
 static unsigned int format_pll_reg(void)
 {
 	unsigned int pllreg = 0;
@@ -510,6 +529,7 @@ static const struct drm_crtc_helper_funcs hibmc_crtc_helper_funcs = {
 	.atomic_flush	= hibmc_crtc_atomic_flush,
 	.atomic_enable	= hibmc_crtc_atomic_enable,
 	.atomic_disable	= hibmc_crtc_atomic_disable,
+	.mode_valid = hibmc_crtc_mode_valid,
 };
 
 int hibmc_de_init(struct hibmc_drm_private *priv)
-- 
2.7.4