On Mon, Mar 20, 2017 at 02:20:21PM +0100, Thierry Reding wrote: > * PGP Signed by an unknown key > > On Tue, Mar 14, 2017 at 04:12:49PM +0200, Peter De Schrijver wrote: > > In normal operation pll_u is under hardware control and has a fixed rate of > > 480MHz. Hardware will turn on pll_u on whenever any of the XUSB > > powerdomains is on. From a software point of view we model this is if pll_u > > is always on using a fixed rate clock. However the bootloader might or > > might not have configured pll_u this way. So we will check the current > > state of pll_u at boot and reconfigure it if required. > > > > There are 3 possiblities at kernel boot: > > 1) pll_u is under hardware control: do nothing > > 2) pll_u is under hardware control and enabled: enable hardware control > > 3) pll_u is disabled: enable pll_u and enable hardware control > > > > In all cases we also check if UTMIPLL is under hardware control at boot > > and configure it for hardware control if that is not the case. > > The same is done during SC7 resume. > > > > Thanks to Joseph Lo <[email protected]> for bug fixes. > > > > Signed-off-by: Peter De Schrijver <[email protected]> > > --- > > drivers/clk/tegra/clk-pll.c | 174 ----------------------- > > drivers/clk/tegra/clk-tegra210.c | 295 > > ++++++++++++++++++++++++++++++++++++--- > > 2 files changed, 272 insertions(+), 197 deletions(-) > > Applied, thanks. > > Do you think this actually fixes a bug? We've had a long standing issue > with booting Debian on a Jetson TX1 which is due to some USB related PLL > failing to lock. This sounds like it could fix that particular issue. >
I think the current approach does have problems if the PLL is already under hw control. Cheers, Peter.
