[PATCH 1/4] drm/i915/intel_dsi: Allow calling intel_dsi_get_pclk with a NULL config

[Hans de Goede <j.w.r.degoede@gmail.com>]

Allow calling intel_dsi_get_pclk without passing in an intel_crtc_state.

This is a preparation patch for reading back the GOP configured DSI
clk during probe.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
---
 drivers/gpu/drm/i915/intel_dsi_pll.c | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_dsi_pll.c b/drivers/gpu/drm/i915/intel_dsi_pll.c
index 2ff2ee7f3b78..71ce6e3157d4 100644
--- a/drivers/gpu/drm/i915/intel_dsi_pll.c
+++ b/drivers/gpu/drm/i915/intel_dsi_pll.c
@@ -279,8 +279,10 @@ static u32 vlv_dsi_get_pclk(struct intel_encoder *encoder, int pipe_bpp,
 	pll_div = vlv_cck_read(dev_priv, CCK_REG_DSI_PLL_DIVIDER);
 	mutex_unlock(&dev_priv->sb_lock);
 
-	config->dsi_pll.ctrl = pll_ctl & ~DSI_PLL_LOCK;
-	config->dsi_pll.div = pll_div;
+	if (config) {
+		config->dsi_pll.ctrl = pll_ctl & ~DSI_PLL_LOCK;
+		config->dsi_pll.div = pll_div;
+	}
 
 	/* mask out other bits and extract the P1 divisor */
 	pll_ctl &= DSI_PLL_P1_POST_DIV_MASK;
@@ -330,6 +332,7 @@ static u32 vlv_dsi_get_pclk(struct intel_encoder *encoder, int pipe_bpp,
 static u32 bxt_dsi_get_pclk(struct intel_encoder *encoder, int pipe_bpp,
 			    struct intel_crtc_state *config)
 {
+	u32 ctrl;
 	u32 pclk;
 	u32 dsi_clk;
 	u32 dsi_ratio;
@@ -342,9 +345,12 @@ static u32 bxt_dsi_get_pclk(struct intel_encoder *encoder, int pipe_bpp,
 		return 0;
 	}
 
-	config->dsi_pll.ctrl = I915_READ(BXT_DSI_PLL_CTL);
+	ctrl = I915_READ(BXT_DSI_PLL_CTL);
+
+	if (config)
+		config->dsi_pll.ctrl = ctrl;
 
-	dsi_ratio = config->dsi_pll.ctrl & BXT_DSI_PLL_RATIO_MASK;
+	dsi_ratio = ctrl & BXT_DSI_PLL_RATIO_MASK;
 
 	dsi_clk = (dsi_ratio * BXT_REF_CLOCK_KHZ) / 2;
 
-- 
2.17.1

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