[PATCH 4/7] clk: mediatek: mt8167: Correct HDMI-related clock definitions

[Luca Leonardo Scorcia]

On the mt8167 SoC, the tvdpll_ck clock is used to clock the DPI1 pixel
signal that is hardwired to the HDMI interface.
The clocks used by those two blocks must match and they have to be changed
according to the mode clock appropriate for the display resolution. Fix a
couple of issues with the current HDMI clock definitions:

- The hdmi_ref divider references the same register and offset of its
  parent tvdpll. Make sure to flag it as a read only divider as its rate
  must be set by the DPI driver only.
- Both hdmi_ref and tvdpll_ck derive their clock from the same tvdpll
  parent clock, but its rate must be set by the DPI driver only. Unset the
  CLK_SET_RATE_PARENT flag that is implicitly set by the FACTOR() macro.

Signed-off-by: Luca Leonardo Scorcia <l.scorcia at gmail.com>
---
 drivers/clk/mediatek/clk-mt8167-apmixedsys.c | 2 +-
 drivers/clk/mediatek/clk-mt8167.c            | 6 +++++-
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/clk/mediatek/clk-mt8167-apmixedsys.c b/drivers/clk/mediatek/clk-mt8167-apmixedsys.c
index 3e8611991de7..a7d38c194759 100644
--- a/drivers/clk/mediatek/clk-mt8167-apmixedsys.c
+++ b/drivers/clk/mediatek/clk-mt8167-apmixedsys.c
@@ -87,7 +87,7 @@ static const struct mtk_pll_data plls[] = {
 
 static const struct mtk_clk_divider adj_divs[] = {
 	DIV_ADJ_FLAG(CLK_APMIXED_HDMI_REF, "hdmi_ref", "tvdpll",
-		     0x1c4, 24, 3, CLK_DIVIDER_POWER_OF_TWO),
+		     0x1c4, 24, 3, CLK_DIVIDER_POWER_OF_TWO | CLK_DIVIDER_READ_ONLY),
 };
 
 static int clk_mt8167_apmixed_probe(struct platform_device *pdev)
diff --git a/drivers/clk/mediatek/clk-mt8167.c b/drivers/clk/mediatek/clk-mt8167.c
index c64d918c37de..a14f0736cdcf 100644
--- a/drivers/clk/mediatek/clk-mt8167.c
+++ b/drivers/clk/mediatek/clk-mt8167.c
@@ -75,7 +75,11 @@ static const struct mtk_fixed_factor top_divs[] = {
 	FACTOR(CLK_TOP_CLK26M, "clk26m_ck", "clk26m", 1, 1),
 	FACTOR(CLK_TOP_CLK26M_D2, "clk26m_d2", "clk26m", 1, 2),
 	FACTOR(CLK_TOP_MIPI_26M, "mipi_26m", "clk26m", 1, 1),
-	FACTOR(CLK_TOP_TVDPLL, "tvdpll_ck", "tvdpll", 1, 1),
+	/*
+	 * The tvdpll_ck clock should not propagate rate changes to its parent
+	 * clock so the dpi driver can have full control over PLL and divider.
+	 */
+	FACTOR_FLAGS(CLK_TOP_TVDPLL, "tvdpll_ck", "tvdpll", 1, 1, 0),
 	FACTOR(CLK_TOP_TVDPLL_D2, "tvdpll_d2", "tvdpll_ck", 1, 2),
 	FACTOR(CLK_TOP_TVDPLL_D4, "tvdpll_d4", "tvdpll_ck", 1, 4),
 	FACTOR(CLK_TOP_TVDPLL_D8, "tvdpll_d8", "tvdpll_ck", 1, 8),
-- 
2.43.0