[PATCH 4.16 124/161] clk: tegra: Fix pll_u rate configuration

From: Greg Kroah-Hartman
Date: Thu May 24 2018 - 05:22:10 EST


4.16-stable review patch. If anyone has any objections, please let me know.

------------------

From: Marcel Ziswiler <marcel@xxxxxxxxxxxx>

[ Upstream commit c35b518f9ba06c9de79fb3ff62eed7462d804995 ]

Turns out latest upstream U-Boot does not configure/enable pll_u 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.ziswiler@xxxxxxxxxxx>
Tested-by: Jon Hunter <jonathanh@xxxxxxxxxx>
Signed-off-by: Thierry Reding <treding@xxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/clk/tegra/clk-pll.c | 2 ++
1 file changed, 2 insertions(+)

--- 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_pl
.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,