[PATCH AUTOSEL 5.5 18/66] drm/msm/dsi/pll: call vco set rate explicitly

[Sasha Levin]

From: Harigovindan P <harigovi at codeaurora.org>

[ Upstream commit c6659785dfb3f8d75f1fe637e4222ff8178f5280 ]

For a given byte clock, if VCO recalc value is exactly same as
vco set rate value, vco_set_rate does not get called assuming
VCO is already set to required value. But Due to GDSC toggle,
VCO values are erased in the HW. To make sure VCO is programmed
correctly, we forcefully call set_rate from vco_prepare.

Signed-off-by: Harigovindan P <harigovi at codeaurora.org>
Reviewed-by: Jeffrey Hugo <jeffrey.l.hugo at gmail.com>
Signed-off-by: Rob Clark <robdclark at chromium.org>
Signed-off-by: Sasha Levin <sashal at kernel.org>
---
 drivers/gpu/drm/msm/dsi/pll/dsi_pll_10nm.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/gpu/drm/msm/dsi/pll/dsi_pll_10nm.c b/drivers/gpu/drm/msm/dsi/pll/dsi_pll_10nm.c
index 8f6100db90ed4..aa9385d5bfff9 100644
--- a/drivers/gpu/drm/msm/dsi/pll/dsi_pll_10nm.c
+++ b/drivers/gpu/drm/msm/dsi/pll/dsi_pll_10nm.c
@@ -411,6 +411,12 @@ static int dsi_pll_10nm_vco_prepare(struct clk_hw *hw)
 	if (pll_10nm->slave)
 		dsi_pll_enable_pll_bias(pll_10nm->slave);
 
+	rc = dsi_pll_10nm_vco_set_rate(hw,pll_10nm->vco_current_rate, 0);
+	if (rc) {
+		pr_err("vco_set_rate failed, rc=%d\n", rc);
+		return rc;
+	}
+
 	/* Start PLL */
 	pll_write(pll_10nm->phy_cmn_mmio + REG_DSI_10nm_PHY_CMN_PLL_CNTRL,
 		  0x01);
-- 
2.20.1