[PATCH 6.8 291/336] clk: sunxi-ng: a64: Set minimum and maximum rate for PLL-MIPI

Greg Kroah-Hartman
2024-05-14T10:51:29Z

From: Frank Oltmanns <frank@oltmanns.dev>

commit 69f16d9b789821183d342719d2ebd4a5ac7178bc upstream.

When the Allwinner A64's TCON0 searches the ideal rate for the connected
panel, it may happen that it requests a rate from its parent PLL-MIPI
which PLL-MIPI does not support.

This happens for example on the Olimex TERES-I laptop where TCON0
requests PLL-MIPI to change to a rate of several GHz which causes the
panel to stay blank. It also happens on the pinephone where a rate of
less than 500 MHz is requested which causes instabilities on some
phones.

Set the minimum and maximum rate of Allwinner A64's PLL-MIPI according
to the Allwinner User Manual.

Fixes: ca1170b69968 ("clk: sunxi-ng: a64: force select PLL_MIPI in TCON0 mux")
Reported-by: Diego Roversi <diegor@tiscali.it>
Closes: https://groups.google.com/g/linux-sunxi/c/Rh-Uqqa66bw
Tested-by: Diego Roversi <diegor@tiscali.it>
Cc: stable@vger.kernel.org
Reviewed-by: Maxime Ripard <mripard@kernel.org>
Signed-off-by: Frank Oltmanns <frank@oltmanns.dev>
Reviewed-by: Jernej Skrabec <jernej.skrabec@gmail.com>
Link: https://lore.kernel.org/r/20240310-pinephone-pll-fixes-v4-2-46fc80c83637@oltmanns.dev
Signed-off-by: Jernej Skrabec <jernej.skrabec@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/clk/sunxi-ng/ccu-sun50i-a64.c | 2 ++
1 file changed, 2 insertions(+)

--- a/drivers/clk/sunxi-ng/ccu-sun50i-a64.c
+++ b/drivers/clk/sunxi-ng/ccu-sun50i-a64.c
@@ -182,6 +182,8 @@ static struct ccu_nkm pll_mipi_clk = {
&ccu_nkm_ops,
CLK_SET_RATE_UNGATE | CLK_SET_RATE_PARENT),
.features = CCU_FEATURE_CLOSEST_RATE,
+ .min_rate = 500000000,
+ .max_rate = 1400000000,
},
};