drm/msm/dsi: do not try reading 28nm vco rate if it's not enabled

Reading VCO rate for this PLL can cause boot stalls, if it is not
enabled. Guard clk_hw_get_rate with a call to
dsi_pll_28nm_clk_is_enabled().

Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: Rob Clark <robdclark@chromium.org>

diff --git a/drivers/gpu/drm/msm/dsi/pll/dsi_pll_28nm.c b/drivers/gpu/drm/msm/dsi/pll/dsi_pll_28nm.c
index 6dffd7f..37a1f99 100644 (file)
--- a/drivers/gpu/drm/msm/dsi/pll/dsi_pll_28nm.c
+++ b/drivers/gpu/drm/msm/dsi/pll/dsi_pll_28nm.c
@@ -447,7 +447,10 @@ static void dsi_pll_28nm_save_state(struct msm_dsi_pll *pll)
        cached_state->postdiv1 =
                        pll_read(base + REG_DSI_28nm_PHY_PLL_POSTDIV1_CFG);
        cached_state->byte_mux = pll_read(base + REG_DSI_28nm_PHY_PLL_VREG_CFG);
-       cached_state->vco_rate = clk_hw_get_rate(&pll->clk_hw);
+       if (dsi_pll_28nm_clk_is_enabled(&pll->clk_hw))
+               cached_state->vco_rate = clk_hw_get_rate(&pll->clk_hw);
+       else
+               cached_state->vco_rate = 0;
 }
 
 static int dsi_pll_28nm_restore_state(struct msm_dsi_pll *pll)