When a USB device is connected to the USB host port on the SAM9N12 then you get "-62" error which seems to indicate USB replies from the device are timing out. Looking around, I saw the USB bus was running at half speed. Going further, it seems that in ..._set_rate() the PLL wasn't actually being adjusted. Writing the multiplier and divider values to the peripheral fixes the bus running at half speed.
Signed-off-by: Marcin Ziemianowicz <mar...@ziemianowicz.com> --- drivers/clk/at91/clk-pll.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/drivers/clk/at91/clk-pll.c b/drivers/clk/at91/clk-pll.c index 534961766ae5..db7155fe9346 100644 --- a/drivers/clk/at91/clk-pll.c +++ b/drivers/clk/at91/clk-pll.c @@ -288,6 +288,14 @@ static int clk_pll_set_rate(struct clk_hw *hw, unsigned long rate, pll->div = div; pll->mul = mul; + // Set the PLL as per above div and mil values. + regmap_update_bits(pll->regmap, AT91_CKGR_PLLBR, + AT91_PMC_DIV | AT91_PMC_MUL, + (div << 0) | (mul << 16)); + + pr_debug("clk-pll: setting new rate, (%lu hz / %u) * %u = %lu hz\n", + parent_rate, div, mul, rate); + return 0; } -- 2.16.3