diff mbox

[v3,2/2] phy: rockchip-inno-usb2: correct 480MHz output clock stable time

Message ID 1479115631-20137-3-git-send-email-wulf@rock-chips.com (mailing list archive)
State New, archived
Headers show

Commit Message

Wu Liang feng Nov. 14, 2016, 9:27 a.m. UTC
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@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(-)

Comments

Doug Anderson Nov. 14, 2016, 6:17 p.m. UTC | #1
William,

On Mon, Nov 14, 2016 at 1:27 AM, William Wu <wulf@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@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@chromium.org>
Wu Liang feng Nov. 15, 2016, 3:23 a.m. UTC | #2
Hi Doug,

在 2016年11月15日 02:17, Doug Anderson 写道:
> William,
>
> On Mon, Nov 14, 2016 at 1:27 AM, William Wu <wulf@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@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@chromium.org>
Thanks! I'll add  Reviewed-by and fix the spelling issue.
>
>
>
diff mbox

Patch

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);
 	}
 
 	return 0;