[PATCH v3 2/2] phy: rockchip-inno-usb2: correct 480MHz output clock stable time
wulf at rock-chips.com
Mon Nov 14 19:23:26 PST 2016
在 2016年11月15日 02:17, Doug Anderson 写道:
> On Mon, Nov 14, 2016 at 1:27 AM, William Wu <wulf at rock-chips.com> wrote:
>> We found that the system crashed due to 480MHz output clock of
>> USB2 PHY was unstable after clock had been enabled by gpu module.
>> Theoretically, 1 millisecond is a critical value for 480MHz
>> output clock stable time, so we try to change the delay time
>> to 1.2 millisecond to avoid this issue.
>> And the commit ed907fb1d7c3 ("phy: rockchip-inno-usb2: correct
>> clk_ops callback") used prepare callbacks instead of enable
>> callbacks to support gate a clk if the operation may sleep. So
>> we can switch from delay to sleep functions.
>> Signed-off-by: William Wu <wulf at rock-chips.com>
>> Changes in v3:
>> - fix kbuild test error: too few arguments to function 'usleep_range'
>> Changes in v2:
>> - use usleep_range() function instead of mdelay()
>> drivers/phy/phy-rockchip-inno-usb2.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>> diff --git a/drivers/phy/phy-rockchip-inno-usb2.c b/drivers/phy/phy-rockchip-inno-usb2.c
>> index 365e077..0e52b25 100644
>> --- a/drivers/phy/phy-rockchip-inno-usb2.c
>> +++ b/drivers/phy/phy-rockchip-inno-usb2.c
>> @@ -166,7 +166,7 @@ static int rockchip_usb2phy_clk480m_prepare(struct clk_hw *hw)
>> return ret;
>> /* waitting for the clk become stable */
>> - mdelay(1);
>> + usleep_range(1200, 1300);
> Sight nit that you could also fix the spelling from "waitting" to "waiting".
> ...but that's pre-existing, so:
> Reviewed-by: Douglas Anderson <dianders at chromium.org>
Thanks! I'll add Reviewed-by and fix the spelling issue.
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