drm/msm/dsi/pll: call vco set rate explicitly

BugLink: https://bugs.launchpad.net/bugs/1867178
[ 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@codeaurora.org>
Reviewed-by: Jeffrey Hugo <jeffrey.l.hugo@gmail.com>
Signed-off-by: Rob Clark <robdclark@chromium.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Paolo Pisati <paolo.pisati@canonical.com>

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 8f6100db90ed498ef730bc852b8b6185c3fddbd4..aa9385d5bfff9dc18aaac9951f4d056c1b8eca1f 100644 (file)
--- 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);