media: atomisp: fix punit_ddr_dvfs_enable() argument for mrfld_power up case
authorTsuchiya Yuto <kitakar@gmail.com>
Sun, 17 Oct 2021 16:19:42 +0000 (01:19 +0900)
committerMauro Carvalho Chehab <mchehab+huawei@kernel.org>
Mon, 15 Nov 2021 08:11:35 +0000 (08:11 +0000)
commit5bfbf65fcca7325e4d89d289b3c286e11220e386
treef8a6278f5932d25492669b215122b1fd51089d93
parentce3015b7212e96db426d0c36f80fd159c91155d1
media: atomisp: fix punit_ddr_dvfs_enable() argument for mrfld_power up case

When comparing with intel-aero atomisp [1], it looks like
punit_ddr_dvfs_enable() should take `false` as an argument on mrfld_power
up case.

Code from the intel-aero kernel [1]:

        int atomisp_mrfld_power_down(struct atomisp_device *isp)
        {
        [...]
/*WA:Enable DVFS*/
if (IS_CHT)
punit_ddr_dvfs_enable(true);

        int atomisp_mrfld_power_up(struct atomisp_device *isp)
        {
        [...]
/*WA for PUNIT, if DVFS enabled, ISP timeout observed*/
if (IS_CHT)
punit_ddr_dvfs_enable(false);

This patch fixes the inverted argument as per the intel-aero code, as
well as its comment. While here, fix space issues for comments in
atomisp_mrfld_power().

Note that it does not seem to be possible to unify the up/down cases for
punit_ddr_dvfs_enable(), i.e., we can't do something like the following:

        if (IS_CHT)
punit_ddr_dvfs_enable(!enable);

because according to the intel-aero code [1], the DVFS is disabled
before "writing 0x0 to ISPSSPM0 bit[1:0]" and the DVFS is enabled after
"writing 0x3 to ISPSSPM0 bit[1:0]".

[1] https://github.com/intel-aero/linux-kernel/blob/a1b673258feb915268377275130c5c5df0eafc82/drivers/media/pci/atomisp/atomisp_driver/atomisp_v4l2.c#L431-L514

Fixes: 0f441fd70b1e ("media: atomisp: simplify the power down/up code")
Signed-off-by: Tsuchiya Yuto <kitakar@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
drivers/staging/media/atomisp/pci/atomisp_v4l2.c