]> git.hungrycats.org Git - linux/commit
clk: qcom: gcc-qcs404: fix initial rate of GPLL3
authorGabor Juhos <j4g8y7@gmail.com>
Tue, 22 Oct 2024 09:45:56 +0000 (11:45 +0200)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Mon, 9 Dec 2024 09:33:05 +0000 (10:33 +0100)
commit8bca39b958f16bfb8a2eaae88c21cae193fed476
tree1c52efee886db8925b8f3145e99818f4e532e438
parent6aa39a78128a2291aa0dc9fb174817c0c0106e53
clk: qcom: gcc-qcs404: fix initial rate of GPLL3

commit 36d202241d234fa4ac50743510d098ad52bd193a upstream.

The comment before the config of the GPLL3 PLL says that the
PLL should run at 930 MHz. In contrary to this, calculating
the frequency from the current configuration values by using
19.2 MHz as input frequency defined in 'qcs404.dtsi', it gives
921.6 MHz:

  $ xo=19200000; l=48; alpha=0x0; alpha_hi=0x0
  $ echo "$xo * ($((l)) + $(((alpha_hi << 32 | alpha) >> 8)) / 2^32)" | bc -l
  921600000.00000000000000000000

Set 'alpha_hi' in the configuration to a value used in downstream
kernels [1][2] in order to get the correct output rate:

  $ xo=19200000; l=48; alpha=0x0; alpha_hi=0x70
  $ echo "$xo * ($((l)) + $(((alpha_hi << 32 | alpha) >> 8)) / 2^32)" | bc -l
  930000000.00000000000000000000

The change is based on static code analysis, compile tested only.

[1] https://git.codelinaro.org/clo/la/kernel/msm-5.4/-/blob/kernel.lnx.5.4.r56-rel/drivers/clk/qcom/gcc-qcs404.c?ref_type=heads#L335
[2} https://git.codelinaro.org/clo/la/kernel/msm-5.15/-/blob/kernel.lnx.5.15.r49-rel/drivers/clk/qcom/gcc-qcs404.c?ref_type=heads#L127

Cc: stable@vger.kernel.org
Fixes: 652f1813c113 ("clk: qcom: gcc: Add global clock controller driver for QCS404")
Signed-off-by: Gabor Juhos <j4g8y7@gmail.com>
Link: https://lore.kernel.org/r/20241022-fix-gcc-qcs404-gpll3-v1-1-c4d30d634d19@gmail.com
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
drivers/clk/qcom/gcc-qcs404.c