diff options
| author | Claudiu Beznea <claudiu.beznea@microchip.com> | 2020-01-17 13:36:46 +0200 |
|---|---|---|
| committer | Stephen Boyd <sboyd@kernel.org> | 2020-02-12 15:31:47 -0800 |
| commit | b0ecf1c6c6e82da4847900fad0272abfd014666d (patch) | |
| tree | 3a58038bef1141903687be7d81721736660e62c7 /drivers/clk | |
| parent | 5bf7f4a249387a6062b9a14c8a77e7ba2fd6a53b (diff) | |
clk: at91: usb: continue if clk_hw_round_rate() return zero
clk_hw_round_rate() may call round rate function of its parents. In case
of SAM9X60 two of USB parrents are PLLA and UPLL. These clocks are
controlled by clk-sam9x60-pll.c driver. The round rate function for this
driver is sam9x60_pll_round_rate() which call in turn
sam9x60_pll_get_best_div_mul(). In case the requested rate is not in the
proper range (rate < characteristics->output[0].min &&
rate > characteristics->output[0].max) the sam9x60_pll_round_rate() will
return a negative number to its caller (called by
clk_core_round_rate_nolock()). clk_hw_round_rate() will return zero in
case a negative number is returned by clk_core_round_rate_nolock(). With
this, the USB clock will continue its rate computation even caller of
clk_hw_round_rate() returned an error. With this, the USB clock on SAM9X60
may not chose the best parent. I detected this after a suspend/resume
cycle on SAM9X60.
Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Link: https://lkml.kernel.org/r/1579261009-4573-2-git-send-email-claudiu.beznea@microchip.com
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
Diffstat (limited to 'drivers/clk')
| -rw-r--r-- | drivers/clk/at91/clk-usb.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/drivers/clk/at91/clk-usb.c b/drivers/clk/at91/clk-usb.c index 22aede42a336..3c0bd7e51b09 100644 --- a/drivers/clk/at91/clk-usb.c +++ b/drivers/clk/at91/clk-usb.c @@ -75,6 +75,9 @@ static int at91sam9x5_clk_usb_determine_rate(struct clk_hw *hw, tmp_parent_rate = req->rate * div; tmp_parent_rate = clk_hw_round_rate(parent, tmp_parent_rate); + if (!tmp_parent_rate) + continue; + tmp_rate = DIV_ROUND_CLOSEST(tmp_parent_rate, div); if (tmp_rate < req->rate) tmp_diff = req->rate - tmp_rate; |