[PATCH v2 1/6] phy: rockchip: samsung-hdptx: Fix rate recalculation for high bpc

[Cristian Ciocaltea <cristian.ciocaltea@collabora.com>]

The PHY PLL can be programmed by an external component, e.g. the
bootloader, just before the recalc_rate() callback is invoked during
devm_clk_hw_register() in the probe path.

Therefore rk_hdptx_phy_clk_recalc_rate() finds the PLL enabled and
attempts to compute the clock rate, while making use of the bpc value
from the HDMI PHY configuration, which always defaults to 8 because
phy_configure() was not run at that point.  As a consequence, the
(re)calculated rate is incorrect when the actual bpc was higher than 8.

Do not rely on any of the hdmi_cfg members when computing the clock rate
and, instead, read the required input data (i.e. bpc), directly from the
hardware registers.

Fixes: 3481fc04d969 ("phy: rockchip: samsung-hdptx: Compute clk rate from PLL config")
Tested-by: Thomas Niederprüm <dubito@online.de>
Tested-by: Simon Wright <simon@symple.nz>
Signed-off-by: Cristian Ciocaltea <cristian.ciocaltea@collabora.com>
---
 drivers/phy/rockchip/phy-rockchip-samsung-hdptx.c | 13 ++++---------
 1 file changed, 4 insertions(+), 9 deletions(-)

diff --git a/drivers/phy/rockchip/phy-rockchip-samsung-hdptx.c b/drivers/phy/rockchip/phy-rockchip-samsung-hdptx.c
index 2d973bc37f07..7fb1c22318bb 100644
--- a/drivers/phy/rockchip/phy-rockchip-samsung-hdptx.c
+++ b/drivers/phy/rockchip/phy-rockchip-samsung-hdptx.c
@@ -2168,7 +2168,7 @@ static u64 rk_hdptx_phy_clk_calc_rate_from_pll_cfg(struct rk_hdptx_phy *hdptx)
 	struct lcpll_config lcpll_hw;
 	struct ropll_config ropll_hw;
 	u64 fout, sdm;
-	u32 mode, val;
+	u32 mode, bpc, val;
 	int ret, i;
 
 	ret = regmap_read(hdptx->regmap, CMN_REG(0008), &mode);
@@ -2266,6 +2266,7 @@ static u64 rk_hdptx_phy_clk_calc_rate_from_pll_cfg(struct rk_hdptx_phy *hdptx)
 	if (ret)
 		return 0;
 	ropll_hw.pms_sdiv = ((val & PLL_PCG_POSTDIV_SEL_MASK) >> 4) + 1;
+	bpc = (FIELD_GET(PLL_PCG_CLK_SEL_MASK, val) << 1) + 8;
 
 	fout = PLL_REF_CLK * ropll_hw.pms_mdiv;
 	if (ropll_hw.sdm_en) {
@@ -2280,7 +2281,7 @@ static u64 rk_hdptx_phy_clk_calc_rate_from_pll_cfg(struct rk_hdptx_phy *hdptx)
 			fout = fout + sdm;
 	}
 
-	return div_u64(fout * 2, ropll_hw.pms_sdiv * 10);
+	return div_u64(fout * 2 * 8, ropll_hw.pms_sdiv * 10 * bpc);
 }
 
 static unsigned long rk_hdptx_phy_clk_recalc_rate(struct clk_hw *hw,
@@ -2288,19 +2289,13 @@ static unsigned long rk_hdptx_phy_clk_recalc_rate(struct clk_hw *hw,
 {
 	struct rk_hdptx_phy *hdptx = to_rk_hdptx_phy(hw);
 	u32 status;
-	u64 rate;
 	int ret;
 
 	ret = regmap_read(hdptx->grf, GRF_HDPTX_CON0, &status);
 	if (ret || !(status & HDPTX_I_PLL_EN))
 		return 0;
 
-	rate = rk_hdptx_phy_clk_calc_rate_from_pll_cfg(hdptx);
-
-	if (hdptx->hdmi_cfg.mode == PHY_HDMI_MODE_FRL)
-		return rate;
-
-	return DIV_ROUND_CLOSEST_ULL(rate * 8, hdptx->hdmi_cfg.bpc);
+	return rk_hdptx_phy_clk_calc_rate_from_pll_cfg(hdptx);
 }
 
 static int rk_hdptx_phy_clk_determine_rate(struct clk_hw *hw,

-- 
2.53.0