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From: Ryan Brue <ryanbrue.dev@gmail.com>
To: Stephen Boyd <sboyd@kernel.org>,
	Brian Masney <bmasney+clk@redhat.com>,
	 Jerome Brunet <jbrunet+clk@baylibre.com>,
	 Matthias Brugger <matthias.bgg@gmail.com>,
	 AngeloGioacchino Del Regno
	<angelogioacchino.delregno@collabora.com>,
	 Chen-Yu Tsai <wenst@chromium.org>
Cc: linux-clk@vger.kernel.org, linux-kernel@vger.kernel.org,
	 linux-arm-kernel@lists.infradead.org,
	linux-mediatek@lists.infradead.org,
	 Ryan Brue <ryanbrue.dev@gmail.com>
Subject: [PATCH 2/2] clk: mediatek: mt6795: fix the FHCTL DDS mask width
Date: Sat, 12 Sep 2026 01:40:38 -0500	[thread overview]
Message-ID: <20260912-mt8173-fix-dds-mask-width-v1-2-3d0c0292c85c@gmail.com> (raw)
In-Reply-To: <20260912-mt8173-fix-dds-mask-width-v1-0-3d0c0292c85c@gmail.com>

All eight PLLs in mt6795's pllfhs[] have pcwbits = 21, so the FHCTL DDS
field is bits 20:0, but _FH() declares .dds_mask = GENMASK(21, 0). As on
MT8173, new_dds from mtk_pll_calc_values() is always 21-bit, so admitting
bit 21 of FHCTL_MON into the poll in hopping_hw_flow() can only make it
time out. The same mask feeds the CON1 write-back and fhctl_set_ssc_regs().

Unlike MT8173 this path has a user: mt6795-sony-xperia-m5.dts switches
FHCTL on for mainpll, mpll and msdcpll, with SSC.

Found by inspection while fixing MT8173. I have no MT6795 hardware, so
this one is untested.

Fixes: f222a1baec5f ("clk: mediatek: mt6795: Add support for frequency hopping through FHCTL")
Assisted-by: LLM
Signed-off-by: Ryan Brue <ryanbrue.dev@gmail.com>
---
 drivers/clk/mediatek/clk-mt6795-apmixedsys.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/clk/mediatek/clk-mt6795-apmixedsys.c b/drivers/clk/mediatek/clk-mt6795-apmixedsys.c
index 123d5d7fea85..ff01cfefc31f 100644
--- a/drivers/clk/mediatek/clk-mt6795-apmixedsys.c
+++ b/drivers/clk/mediatek/clk-mt6795-apmixedsys.c
@@ -79,7 +79,7 @@ enum fh_pll_id {
 			.fh_id = _fhid,					\
 			.fh_ver = FHCTL_PLLFH_V1,			\
 			.fhx_offset = _offset,				\
-			.dds_mask = GENMASK(21, 0),			\
+			.dds_mask = GENMASK(20, 0),			\
 			.slope0_value = _slope,				\
 			.slope1_value = _slope,				\
 			.sfstrx_en = BIT(2),				\

-- 
2.55.0



      parent reply	other threads:[~2026-09-12  6:41 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-09-12  6:40 [PATCH 0/2] clk: mediatek: Fix FHCTL DDS mask widths for mt8173, mt6795 Ryan Brue
2026-09-12  6:40 ` [PATCH 1/2] clk: mediatek: mt8173: fix the FHCTL DDS mask width Ryan Brue
2026-09-12  6:40 ` Ryan Brue [this message]

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