[PATCH 6.1 179/232] clk: meson: gxbb: Limit the HDMI PLL OD to /4 on GXL/GXM SoCs

Sasha Levin
2026-02-28T18:14:01Z

From: Martin Blumenstingl <martin.blumenstingl@googlemail.com>

[ Upstream commit 5b1a43950fd3162af0ce52b13c14a2d29b179d4f ]

GXBB has the HDMI PLL OD in the HHI_HDMI_PLL_CNTL2 register while for
GXL/GXM the OD has moved to HHI_HDMI_PLL_CNTL3. At first glance the rest
of the OD setup seems identical.

However, looking at the downstream kernel sources as well as testing
shows that GXL only supports three OD values:
- register value 0 means: divide by 1
- register value 1 means: divide by 2
- register value 2 means: divide by 4

Using register value 3 (which on GXBB means: divide by 8) still divides
by 4 as verified using meson-clk-measure. Downstream sources are also
only using OD register values 0, 1 and 2 for GXL (while for GXBB the
downstream kernel sources are also using value 3).

Add clk_div_table and have it replace the CLK_DIVIDER_POWER_OF_TWO flag
to make the kernel's view of this register match with how the hardware
actually works.

Fixes: 69d92293274b ("clk: meson: add the gxl hdmi pll")
Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Link: https://lore.kernel.org/r/20260105204710.447779-2-martin.blumenstingl@googlemail.com
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/clk/meson/gxbb.c | 17 ++++++++++++++---
1 file changed, 14 insertions(+), 3 deletions(-)

diff --git a/drivers/clk/meson/gxbb.c b/drivers/clk/meson/gxbb.c
index 35bc13e73c0dd..6f3918f0a7826 100644
--- a/drivers/clk/meson/gxbb.c
+++ b/drivers/clk/meson/gxbb.c
@@ -316,12 +316,23 @@ static struct clk_regmap gxbb_hdmi_pll = {
},
};

+/*
+ * GXL hdmi OD dividers are POWER_OF_TWO dividers but limited to /4.
+ * A divider value of 3 should map to /8 but instead map /4 so ignore it.
+ */
+static const struct clk_div_table gxl_hdmi_pll_od_div_table[] = {
+ { .val = 0, .div = 1 },
+ { .val = 1, .div = 2 },
+ { .val = 2, .div = 4 },
+ { /* sentinel */ }
+};
+
static struct clk_regmap gxl_hdmi_pll_od = {
.data = &(struct clk_regmap_div_data){
.offset = HHI_HDMI_PLL_CNTL + 8,
.shift = 21,
.width = 2,
- .flags = CLK_DIVIDER_POWER_OF_TWO,
+ .table = gxl_hdmi_pll_od_div_table,
},
.hw.init = &(struct clk_init_data){
.name = "hdmi_pll_od",
@@ -339,7 +350,7 @@ static struct clk_regmap gxl_hdmi_pll_od2 = {
.offset = HHI_HDMI_PLL_CNTL + 8,
.shift = 23,
.width = 2,
- .flags = CLK_DIVIDER_POWER_OF_TWO,
+ .table = gxl_hdmi_pll_od_div_table,
},
.hw.init = &(struct clk_init_data){
.name = "hdmi_pll_od2",
@@ -357,7 +368,7 @@ static struct clk_regmap gxl_hdmi_pll = {
.offset = HHI_HDMI_PLL_CNTL + 8,
.shift = 19,
.width = 2,
- .flags = CLK_DIVIDER_POWER_OF_TWO,
+ .table = gxl_hdmi_pll_od_div_table,
},
.hw.init = &(struct clk_init_data){
.name = "hdmi_pll",
--
2.51.0