clk: rockchip: rk3288: Limit use of USB PHY clock to USB
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Message ID 20190411175917.173566-1-mka@chromium.org
State New
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  • clk: rockchip: rk3288: Limit use of USB PHY clock to USB
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Commit Message

Matthias Kaehlcke April 11, 2019, 5:59 p.m. UTC
The USB PHY clock can be configured as (grand) parent of uart0_sclk and
sclk_gpu. It has been observed that UART0 doesn't work reliably in high
speed mode with the PHY clock as input when certain USB devices are
plugged to the USB HOST1 port (see https://crrev.com/c/320543).

Prefix the name of the PHY clock with a '.' in the non-USB muxes to
effectively remove the clock as input from these muxes.

Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
---
 drivers/clk/rockchip/clk-rk3288.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

Comments

Heiko Stuebner April 11, 2019, 7:03 p.m. UTC | #1
Hi Matthias,

Am Donnerstag, 11. April 2019, 19:59:17 CEST schrieb Matthias Kaehlcke:
> The USB PHY clock can be configured as (grand) parent of uart0_sclk and
> sclk_gpu. It has been observed that UART0 doesn't work reliably in high
> speed mode with the PHY clock as input when certain USB devices are
> plugged to the USB HOST1 port (see https://crrev.com/c/320543).
> 
> Prefix the name of the PHY clock with a '.' in the non-USB muxes to
> effectively remove the clock as input from these muxes.
> 
> Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
> ---
>  drivers/clk/rockchip/clk-rk3288.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/clk/rockchip/clk-rk3288.c b/drivers/clk/rockchip/clk-rk3288.c
> index 5a67b7869960..677bc5485201 100644
> --- a/drivers/clk/rockchip/clk-rk3288.c
> +++ b/drivers/clk/rockchip/clk-rk3288.c
> @@ -200,8 +200,8 @@ PNAME(mux_aclk_cpu_src_p)	= { "cpll_aclk_cpu", "gpll_aclk_cpu" };
>  PNAME(mux_pll_src_cpll_gpll_p)		= { "cpll", "gpll" };
>  PNAME(mux_pll_src_npll_cpll_gpll_p)	= { "npll", "cpll", "gpll" };
>  PNAME(mux_pll_src_cpll_gpll_npll_p)	= { "cpll", "gpll", "npll" };
> -PNAME(mux_pll_src_cpll_gpll_usb480m_p)	= { "cpll", "gpll", "usbphy480m_src" };
> -PNAME(mux_pll_src_cpll_gll_usb_npll_p)	= { "cpll", "gpll", "usbphy480m_src", "npll" };
> +PNAME(mux_pll_src_cpll_gpll_usb480m_p)	= { "cpll", "gpll", ".usbphy480m_src" };
> +PNAME(mux_pll_src_cpll_gll_usb_npll_p)	= { "cpll", "gpll", ".usbphy480m_src", "npll" };

In general I like to have things like the clock-tree described fully
and let the kernel handle correct sourcing ... but:

As you write this seems like a systemic problem when just connecting
random peripherals can create unstable clock source frequencies,
so I tend to agree here ... but:

Can we please find a more "talking" name for this ... because as with the
above someone will find the "." and submit a fix for it ;-) .

So just name it "unstable_dummy" or so?


Heiko
Matthias Kaehlcke April 12, 2019, 12:16 a.m. UTC | #2
Hi Heiko,

On Thu, Apr 11, 2019 at 09:03:07PM +0200, Heiko Stübner wrote:
> Hi Matthias,
> 
> Am Donnerstag, 11. April 2019, 19:59:17 CEST schrieb Matthias Kaehlcke:
> > The USB PHY clock can be configured as (grand) parent of uart0_sclk and
> > sclk_gpu. It has been observed that UART0 doesn't work reliably in high
> > speed mode with the PHY clock as input when certain USB devices are
> > plugged to the USB HOST1 port (see https://crrev.com/c/320543).
> > 
> > Prefix the name of the PHY clock with a '.' in the non-USB muxes to
> > effectively remove the clock as input from these muxes.
> > 
> > Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
> > ---
> >  drivers/clk/rockchip/clk-rk3288.c | 4 ++--
> >  1 file changed, 2 insertions(+), 2 deletions(-)
> > 
> > diff --git a/drivers/clk/rockchip/clk-rk3288.c b/drivers/clk/rockchip/clk-rk3288.c
> > index 5a67b7869960..677bc5485201 100644
> > --- a/drivers/clk/rockchip/clk-rk3288.c
> > +++ b/drivers/clk/rockchip/clk-rk3288.c
> > @@ -200,8 +200,8 @@ PNAME(mux_aclk_cpu_src_p)	= { "cpll_aclk_cpu", "gpll_aclk_cpu" };
> >  PNAME(mux_pll_src_cpll_gpll_p)		= { "cpll", "gpll" };
> >  PNAME(mux_pll_src_npll_cpll_gpll_p)	= { "npll", "cpll", "gpll" };
> >  PNAME(mux_pll_src_cpll_gpll_npll_p)	= { "cpll", "gpll", "npll" };
> > -PNAME(mux_pll_src_cpll_gpll_usb480m_p)	= { "cpll", "gpll", "usbphy480m_src" };
> > -PNAME(mux_pll_src_cpll_gll_usb_npll_p)	= { "cpll", "gpll", "usbphy480m_src", "npll" };
> > +PNAME(mux_pll_src_cpll_gpll_usb480m_p)	= { "cpll", "gpll", ".usbphy480m_src" };
> > +PNAME(mux_pll_src_cpll_gll_usb_npll_p)	= { "cpll", "gpll", ".usbphy480m_src", "npll" };
> 
> In general I like to have things like the clock-tree described fully
> and let the kernel handle correct sourcing ... but:
> 
> As you write this seems like a systemic problem when just connecting
> random peripherals can create unstable clock source frequencies,
> so I tend to agree here ... but:
> 
> Can we please find a more "talking" name for this ... because as with the
> above someone will find the "." and submit a fix for it ;-) .
> 
> So just name it "unstable_dummy" or so?

I looked for some common pattern, but couldn't find one. I liked the
'.' since it leaves the name of the clock mostly intact, just hiding
it (similar to a leading '.' in a Linux file system). But I agree that
it might not be expressive enough. I still like the idea to keep the
clock name around for reference, maybe we could name it
"unstable:usbphy480m_src" or similar. If you don't object I'll send a
patch with this some time tomorrow.

Thanks

Matthias
Heiko Stuebner April 12, 2019, 9:30 a.m. UTC | #3
Am Freitag, 12. April 2019, 02:16:57 CEST schrieb Matthias Kaehlcke:
> Hi Heiko,
> 
> On Thu, Apr 11, 2019 at 09:03:07PM +0200, Heiko Stübner wrote:
> > Hi Matthias,
> > 
> > Am Donnerstag, 11. April 2019, 19:59:17 CEST schrieb Matthias Kaehlcke:
> > > The USB PHY clock can be configured as (grand) parent of uart0_sclk and
> > > sclk_gpu. It has been observed that UART0 doesn't work reliably in high
> > > speed mode with the PHY clock as input when certain USB devices are
> > > plugged to the USB HOST1 port (see https://crrev.com/c/320543).
> > > 
> > > Prefix the name of the PHY clock with a '.' in the non-USB muxes to
> > > effectively remove the clock as input from these muxes.
> > > 
> > > Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
> > > ---
> > >  drivers/clk/rockchip/clk-rk3288.c | 4 ++--
> > >  1 file changed, 2 insertions(+), 2 deletions(-)
> > > 
> > > diff --git a/drivers/clk/rockchip/clk-rk3288.c b/drivers/clk/rockchip/clk-rk3288.c
> > > index 5a67b7869960..677bc5485201 100644
> > > --- a/drivers/clk/rockchip/clk-rk3288.c
> > > +++ b/drivers/clk/rockchip/clk-rk3288.c
> > > @@ -200,8 +200,8 @@ PNAME(mux_aclk_cpu_src_p)	= { "cpll_aclk_cpu", "gpll_aclk_cpu" };
> > >  PNAME(mux_pll_src_cpll_gpll_p)		= { "cpll", "gpll" };
> > >  PNAME(mux_pll_src_npll_cpll_gpll_p)	= { "npll", "cpll", "gpll" };
> > >  PNAME(mux_pll_src_cpll_gpll_npll_p)	= { "cpll", "gpll", "npll" };
> > > -PNAME(mux_pll_src_cpll_gpll_usb480m_p)	= { "cpll", "gpll", "usbphy480m_src" };
> > > -PNAME(mux_pll_src_cpll_gll_usb_npll_p)	= { "cpll", "gpll", "usbphy480m_src", "npll" };
> > > +PNAME(mux_pll_src_cpll_gpll_usb480m_p)	= { "cpll", "gpll", ".usbphy480m_src" };
> > > +PNAME(mux_pll_src_cpll_gll_usb_npll_p)	= { "cpll", "gpll", ".usbphy480m_src", "npll" };
> > 
> > In general I like to have things like the clock-tree described fully
> > and let the kernel handle correct sourcing ... but:
> > 
> > As you write this seems like a systemic problem when just connecting
> > random peripherals can create unstable clock source frequencies,
> > so I tend to agree here ... but:
> > 
> > Can we please find a more "talking" name for this ... because as with the
> > above someone will find the "." and submit a fix for it ;-) .
> > 
> > So just name it "unstable_dummy" or so?
> 
> I looked for some common pattern, but couldn't find one. I liked the
> '.' since it leaves the name of the clock mostly intact, just hiding
> it (similar to a leading '.' in a Linux file system). But I agree that
> it might not be expressive enough. I still like the idea to keep the
> clock name around for reference, maybe we could name it
> "unstable:usbphy480m_src" or similar. If you don't object I'll send a
> patch with this some time tomorrow.

I've just adapted the patch to use the new parent-name you suggested
and applied it for 5.2 So no need to resend :-) .

Thanks
Heiko
Matthias Kaehlcke April 12, 2019, 6:02 p.m. UTC | #4
On Fri, Apr 12, 2019 at 11:30:37AM +0200, Heiko Stübner wrote:
> Am Freitag, 12. April 2019, 02:16:57 CEST schrieb Matthias Kaehlcke:
> > Hi Heiko,
> > 
> > On Thu, Apr 11, 2019 at 09:03:07PM +0200, Heiko Stübner wrote:
> > > Hi Matthias,
> > > 
> > > Am Donnerstag, 11. April 2019, 19:59:17 CEST schrieb Matthias Kaehlcke:
> > > > The USB PHY clock can be configured as (grand) parent of uart0_sclk and
> > > > sclk_gpu. It has been observed that UART0 doesn't work reliably in high
> > > > speed mode with the PHY clock as input when certain USB devices are
> > > > plugged to the USB HOST1 port (see https://crrev.com/c/320543).
> > > > 
> > > > Prefix the name of the PHY clock with a '.' in the non-USB muxes to
> > > > effectively remove the clock as input from these muxes.
> > > > 
> > > > Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
> > > > ---
> > > >  drivers/clk/rockchip/clk-rk3288.c | 4 ++--
> > > >  1 file changed, 2 insertions(+), 2 deletions(-)
> > > > 
> > > > diff --git a/drivers/clk/rockchip/clk-rk3288.c b/drivers/clk/rockchip/clk-rk3288.c
> > > > index 5a67b7869960..677bc5485201 100644
> > > > --- a/drivers/clk/rockchip/clk-rk3288.c
> > > > +++ b/drivers/clk/rockchip/clk-rk3288.c
> > > > @@ -200,8 +200,8 @@ PNAME(mux_aclk_cpu_src_p)	= { "cpll_aclk_cpu", "gpll_aclk_cpu" };
> > > >  PNAME(mux_pll_src_cpll_gpll_p)		= { "cpll", "gpll" };
> > > >  PNAME(mux_pll_src_npll_cpll_gpll_p)	= { "npll", "cpll", "gpll" };
> > > >  PNAME(mux_pll_src_cpll_gpll_npll_p)	= { "cpll", "gpll", "npll" };
> > > > -PNAME(mux_pll_src_cpll_gpll_usb480m_p)	= { "cpll", "gpll", "usbphy480m_src" };
> > > > -PNAME(mux_pll_src_cpll_gll_usb_npll_p)	= { "cpll", "gpll", "usbphy480m_src", "npll" };
> > > > +PNAME(mux_pll_src_cpll_gpll_usb480m_p)	= { "cpll", "gpll", ".usbphy480m_src" };
> > > > +PNAME(mux_pll_src_cpll_gll_usb_npll_p)	= { "cpll", "gpll", ".usbphy480m_src", "npll" };
> > > 
> > > In general I like to have things like the clock-tree described fully
> > > and let the kernel handle correct sourcing ... but:
> > > 
> > > As you write this seems like a systemic problem when just connecting
> > > random peripherals can create unstable clock source frequencies,
> > > so I tend to agree here ... but:
> > > 
> > > Can we please find a more "talking" name for this ... because as with the
> > > above someone will find the "." and submit a fix for it ;-) .
> > > 
> > > So just name it "unstable_dummy" or so?
> > 
> > I looked for some common pattern, but couldn't find one. I liked the
> > '.' since it leaves the name of the clock mostly intact, just hiding
> > it (similar to a leading '.' in a Linux file system). But I agree that
> > it might not be expressive enough. I still like the idea to keep the
> > clock name around for reference, maybe we could name it
> > "unstable:usbphy480m_src" or similar. If you don't object I'll send a
> > patch with this some time tomorrow.
> 
> I've just adapted the patch to use the new parent-name you suggested
> and applied it for 5.2 So no need to resend :-) .

Pefect, thanks!

I don't see the patch in the git.kernel.org repo (nor
https://lore.kernel.org/patchwork/patch/1060781/), looks like the push
is still pending.

Cheers

Matthias
Heiko Stuebner April 12, 2019, 6:55 p.m. UTC | #5
Am Freitag, 12. April 2019, 20:02:55 CEST schrieb Matthias Kaehlcke:
> On Fri, Apr 12, 2019 at 11:30:37AM +0200, Heiko Stübner wrote:
> > Am Freitag, 12. April 2019, 02:16:57 CEST schrieb Matthias Kaehlcke:
> > > Hi Heiko,
> > > 
> > > On Thu, Apr 11, 2019 at 09:03:07PM +0200, Heiko Stübner wrote:
> > > > Hi Matthias,
> > > > 
> > > > Am Donnerstag, 11. April 2019, 19:59:17 CEST schrieb Matthias Kaehlcke:
> > > > > The USB PHY clock can be configured as (grand) parent of uart0_sclk and
> > > > > sclk_gpu. It has been observed that UART0 doesn't work reliably in high
> > > > > speed mode with the PHY clock as input when certain USB devices are
> > > > > plugged to the USB HOST1 port (see https://crrev.com/c/320543).
> > > > > 
> > > > > Prefix the name of the PHY clock with a '.' in the non-USB muxes to
> > > > > effectively remove the clock as input from these muxes.
> > > > > 
> > > > > Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
> > > > > ---
> > > > >  drivers/clk/rockchip/clk-rk3288.c | 4 ++--
> > > > >  1 file changed, 2 insertions(+), 2 deletions(-)
> > > > > 
> > > > > diff --git a/drivers/clk/rockchip/clk-rk3288.c b/drivers/clk/rockchip/clk-rk3288.c
> > > > > index 5a67b7869960..677bc5485201 100644
> > > > > --- a/drivers/clk/rockchip/clk-rk3288.c
> > > > > +++ b/drivers/clk/rockchip/clk-rk3288.c
> > > > > @@ -200,8 +200,8 @@ PNAME(mux_aclk_cpu_src_p)	= { "cpll_aclk_cpu", "gpll_aclk_cpu" };
> > > > >  PNAME(mux_pll_src_cpll_gpll_p)		= { "cpll", "gpll" };
> > > > >  PNAME(mux_pll_src_npll_cpll_gpll_p)	= { "npll", "cpll", "gpll" };
> > > > >  PNAME(mux_pll_src_cpll_gpll_npll_p)	= { "cpll", "gpll", "npll" };
> > > > > -PNAME(mux_pll_src_cpll_gpll_usb480m_p)	= { "cpll", "gpll", "usbphy480m_src" };
> > > > > -PNAME(mux_pll_src_cpll_gll_usb_npll_p)	= { "cpll", "gpll", "usbphy480m_src", "npll" };
> > > > > +PNAME(mux_pll_src_cpll_gpll_usb480m_p)	= { "cpll", "gpll", ".usbphy480m_src" };
> > > > > +PNAME(mux_pll_src_cpll_gll_usb_npll_p)	= { "cpll", "gpll", ".usbphy480m_src", "npll" };
> > > > 
> > > > In general I like to have things like the clock-tree described fully
> > > > and let the kernel handle correct sourcing ... but:
> > > > 
> > > > As you write this seems like a systemic problem when just connecting
> > > > random peripherals can create unstable clock source frequencies,
> > > > so I tend to agree here ... but:
> > > > 
> > > > Can we please find a more "talking" name for this ... because as with the
> > > > above someone will find the "." and submit a fix for it ;-) .
> > > > 
> > > > So just name it "unstable_dummy" or so?
> > > 
> > > I looked for some common pattern, but couldn't find one. I liked the
> > > '.' since it leaves the name of the clock mostly intact, just hiding
> > > it (similar to a leading '.' in a Linux file system). But I agree that
> > > it might not be expressive enough. I still like the idea to keep the
> > > clock name around for reference, maybe we could name it
> > > "unstable:usbphy480m_src" or similar. If you don't object I'll send a
> > > patch with this some time tomorrow.
> > 
> > I've just adapted the patch to use the new parent-name you suggested
> > and applied it for 5.2 So no need to resend :-) .
> 
> Pefect, thanks!
> 
> I don't see the patch in the git.kernel.org repo (nor
> https://lore.kernel.org/patchwork/patch/1060781/), looks like the push
> is still pending.

oops, I really had forgotten the push ... done now with your patch at
https://git.kernel.org/pub/scm/linux/kernel/git/mmind/linux-rockchip.git/log/?h=v5.2-clk/next

Heiko

Patch
diff mbox series

diff --git a/drivers/clk/rockchip/clk-rk3288.c b/drivers/clk/rockchip/clk-rk3288.c
index 5a67b7869960..677bc5485201 100644
--- a/drivers/clk/rockchip/clk-rk3288.c
+++ b/drivers/clk/rockchip/clk-rk3288.c
@@ -200,8 +200,8 @@  PNAME(mux_aclk_cpu_src_p)	= { "cpll_aclk_cpu", "gpll_aclk_cpu" };
 PNAME(mux_pll_src_cpll_gpll_p)		= { "cpll", "gpll" };
 PNAME(mux_pll_src_npll_cpll_gpll_p)	= { "npll", "cpll", "gpll" };
 PNAME(mux_pll_src_cpll_gpll_npll_p)	= { "cpll", "gpll", "npll" };
-PNAME(mux_pll_src_cpll_gpll_usb480m_p)	= { "cpll", "gpll", "usbphy480m_src" };
-PNAME(mux_pll_src_cpll_gll_usb_npll_p)	= { "cpll", "gpll", "usbphy480m_src", "npll" };
+PNAME(mux_pll_src_cpll_gpll_usb480m_p)	= { "cpll", "gpll", ".usbphy480m_src" };
+PNAME(mux_pll_src_cpll_gll_usb_npll_p)	= { "cpll", "gpll", ".usbphy480m_src", "npll" };
 
 PNAME(mux_mmc_src_p)	= { "cpll", "gpll", "xin24m", "xin24m" };
 PNAME(mux_i2s_pre_p)	= { "i2s_src", "i2s_frac", "ext_i2s", "xin12m" };