On Mon, 2018-02-26 at 15:42 +0300, Dmitry Osipenko wrote:
> On 23.02.2018 02:04, Marcel Ziswiler wrote:
> > Turns out latest upstream U-Boot does not configure/enable pllu
> > which
> > leaves it at some default rate of 500 kHz:
> >
> > root@apalis-t30:~# cat /sys/kernel/debug/clk/clk_summary | grep
> > pll_u
> > pll_u 3 3 0 500000
> > 0
> >
> > Of course this won't quite work leading to the following messages:
> >
> > [ 6.559593] usb 2-1: new full-speed USB device number 2 using
> > tegra-
> > ehci
> > [ 11.759173] usb 2-1: device descriptor read/64, error -110
> > [ 27.119453] usb 2-1: device descriptor read/64, error -110
> > [ 27.389217] usb 2-1: new full-speed USB device number 3 using
> > tegra-
> > ehci
> > [ 32.559454] usb 2-1: device descriptor read/64, error -110
> > [ 47.929777] usb 2-1: device descriptor read/64, error -110
> > [ 48.049658] usb usb2-port1: attempt power cycle
> > [ 48.759475] usb 2-1: new full-speed USB device number 4 using
> > tegra-
> > ehci
> > [ 59.349457] usb 2-1: device not accepting address 4, error -110
> > [ 59.509449] usb 2-1: new full-speed USB device number 5 using
> > tegra-
> > ehci
> > [ 70.069457] usb 2-1: device not accepting address 5, error -110
> > [ 70.079721] usb usb2-port1: unable to enumerate USB device
> >
> > Fix this by actually allowing the rate also being set from within
> > the Linux kernel.
> >
> > Signed-off-by: Marcel Ziswiler <marcel.ziswi...@toradex.com>
> >
> > ---
> >
> > drivers/clk/tegra/clk-pll.c | 2 ++
> > 1 file changed, 2 insertions(+)
> >
> > diff --git a/drivers/clk/tegra/clk-pll.c b/drivers/clk/tegra/clk-
> > pll.c
> > index 7c369e21c91c..830d1c87fa7c 100644
> > --- a/drivers/clk/tegra/clk-pll.c
> > +++ b/drivers/clk/tegra/clk-pll.c
> > @@ -1151,6 +1151,8 @@ static const struct clk_ops
> > tegra_clk_pllu_ops = {
> > .enable = clk_pllu_enable,
> > .disable = clk_pll_disable,
> > .recalc_rate = clk_pll_recalc_rate,
> > + .round_rate = clk_pll_round_rate,
> > + .set_rate = clk_pll_set_rate,
> > };
> >
> > static int _pll_fixed_mdiv(struct tegra_clk_pll_params
> > *pll_params,
> >
>
> Tegra's USB PHY driver only enables clock and clk driver doesn't
> specify the
> clock rate in the init table. Could you please clarify where in the
> kernels code
> PLL_U rate is getting set?
I guess that would be according to the following table isn't it:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree
/drivers/clk/tegra/clk-tegra30.c?h=v4.16-rc3#n287
