* [PATCH v3] clk: at91: PLL recalc_rate() now using cached MUL+DIV values
@ 2018-04-29 13:17 ` Boris Brezillon
0 siblings, 0 replies; 12+ messages in thread
From: Boris Brezillon @ 2018-04-29 13:17 UTC (permalink / raw)
To: linux-arm-kernel
Hi Marcin,
On Fri, 27 Apr 2018 13:56:09 -0400
Marcin Ziemianowicz <marcin@ziemianowicz.com> wrote:
> Stephen Boyd <sboyd@kernel.org>,
> linux-clk at vger.kernel.org,
> linux-arm-kernel at lists.infradead.org,
> linux-kernel at vger.kernel.org
> Bcc:
> Subject: [PATCH v3] clk: at91: PLL recalc_rate() now using cached MUL and DIV
> values
> Reply-To:
Hm, I don't know how you prepared and sent your patch, but you shouldn't
have these fields in the body of your email. Please use git format-patch
to prepare the patch and then git send-email to send it.
>
> 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. Based on a logic sniffer, I saw the USB bus was running
> at half speed.
>
> The PLL code uses cached MUL and DIV values which get set in set_rate()
> and applied in prepare(), but the recalc_rate() function instead
> queries the hardware instead of using these cached values. Therefore,
> if recalc_rate() is called between a set_rate() and prepare(), the
> wrong frequency is calculated and later the USB clock divider for the
> SAM9N12 SOC will be configured for an incorrect clock.
>
> In my case, the PLL hardware was set to 96 Mhz before the OHCI
> driver loads, and therefore the usb clock divider was being set
> to /2 even though the OHCI driver set the PLL to 48 Mhz.
>
> As an alternative explanation, I noticed this was fixed in the past:
> http://lists.infradead.org/pipermail/linux-arm-kernel/2014-September/283502.html
> but was later changed back via a large patch (maybe by mistake?):
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=1bdf02326b71eae7e9b4b335b881856aaf9d1af6
Yep, probably by mistake. I started this rework long before it has been
submitted to the ML, so I probably messed something up when rebasing.
Also, prefer commit IDs to links to the ML archive. The above would
sentence would give:
"
As an alternative explanation, I noticed this was fixed in the past by
87e2ed338f1b ("clk: at91: fix recalc_rate implementation of PLL
driver") but the bug was later re-introduced by 1bdf02326b71 ("clk:
at91: make use of syscon/regmap internally").
"
The following comment and the changelog should be placed after the
'---' line, so that it's not part of the commit message.
> Thank you for bearing with me about this Boris.
>
> Changes since V2:
> Removed all logging/debug messages I added
> > Comment by Boris Brezillon about my fix being wrong addressed
> Changes since V1:
> Added patch set cover letter
> Shortened lines which were over >80 characters long
> > Comment by Greg Kroah-Hartman about "from" field in email addressed
> > Comment by Alan Stern about redundant debug lines addressed
>
You should add Fixes and Cc-stable tags so that the fix is backported
to stable branches:
Fixes: 1bdf02326b71 ("clk: at91: make use of syscon/regmap internally)
Cc: <stable@vger.kernel.org>
> Signed-off-by: Marcin Ziemianowicz <marcin@ziemianowicz.com>
> ---
> drivers/clk/at91/clk-pll.c | 13 +------------
> 1 file changed, 1 insertion(+), 12 deletions(-)
>
> diff --git a/drivers/clk/at91/clk-pll.c b/drivers/clk/at91/clk-pll.c
> index 7d3223fc..cc6e0364 100644
> --- a/drivers/clk/at91/clk-pll.c
> +++ b/drivers/clk/at91/clk-pll.c
> @@ -132,19 +132,8 @@ static unsigned long clk_pll_recalc_rate(struct clk_hw *hw,
> unsigned long parent_rate)
> {
> struct clk_pll *pll = to_clk_pll(hw);
> - unsigned int pllr;
> - u16 mul;
> - u8 div;
> -
> - regmap_read(pll->regmap, PLL_REG(pll->id), &pllr);
> -
> - div = PLL_DIV(pllr);
> - mul = PLL_MUL(pllr, pll->layout);
> -
> - if (!div || !mul)
> - return 0;
>
> - return (parent_rate / div) * (mul + 1);
> + return return (parent_rate / pll->div) * (pll->mul + 1);
The fix looks good. Let me know if you struggle with git
format-patch/send-email and I'll try to help you (or send the patch for
you if you don't care learning the process, but I think it's better if
you learn how to submit patches).
Thanks,
Boris
> }
>
> static long clk_pll_get_best_div_mul(struct clk_pll *pll, unsigned long rate,
^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [PATCH v3] clk: at91: PLL recalc_rate() now using cached MUL+DIV values
2018-04-29 13:17 ` Boris Brezillon
@ 2018-04-29 13:19 ` Boris Brezillon
-1 siblings, 0 replies; 12+ messages in thread
From: Boris Brezillon @ 2018-04-29 13:19 UTC (permalink / raw)
To: Marcin Ziemianowicz
Cc: Boris Brezillon, Nicolas Ferre, Alexandre Belloni,
Michael Turquette, Stephen Boyd, linux-clk, linux-arm-kernel,
linux-kernel
On Sun, 29 Apr 2018 15:17:10 +0200
Boris Brezillon <boris.brezillon@bootlin.com> wrote:
> Hi Marcin,
>
> On Fri, 27 Apr 2018 13:56:09 -0400
> Marcin Ziemianowicz <marcin@ziemianowicz.com> wrote:
>
> > Stephen Boyd <sboyd@kernel.org>,
> > linux-clk@vger.kernel.org,
> > linux-arm-kernel@lists.infradead.org,
> > linux-kernel@vger.kernel.org
> > Bcc:
> > Subject: [PATCH v3] clk: at91: PLL recalc_rate() now using cached MUL and DIV
> > values
> > Reply-To:
>
> Hm, I don't know how you prepared and sent your patch, but you shouldn't
> have these fields in the body of your email. Please use git format-patch
> to prepare the patch and then git send-email to send it.
>
> >
> > 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. Based on a logic sniffer, I saw the USB bus was running
> > at half speed.
> >
> > The PLL code uses cached MUL and DIV values which get set in set_rate()
> > and applied in prepare(), but the recalc_rate() function instead
> > queries the hardware instead of using these cached values. Therefore,
> > if recalc_rate() is called between a set_rate() and prepare(), the
> > wrong frequency is calculated and later the USB clock divider for the
> > SAM9N12 SOC will be configured for an incorrect clock.
> >
> > In my case, the PLL hardware was set to 96 Mhz before the OHCI
> > driver loads, and therefore the usb clock divider was being set
> > to /2 even though the OHCI driver set the PLL to 48 Mhz.
> >
> > As an alternative explanation, I noticed this was fixed in the past:
> > http://lists.infradead.org/pipermail/linux-arm-kernel/2014-September/283502.html
> > but was later changed back via a large patch (maybe by mistake?):
> > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=1bdf02326b71eae7e9b4b335b881856aaf9d1af6
>
> Yep, probably by mistake. I started this rework long before it has been
> submitted to the ML, so I probably messed something up when rebasing.
>
> Also, prefer commit IDs to links to the ML archive. The above would
> sentence would give:
>
> "
> As an alternative explanation, I noticed this was fixed in the past by
> 87e2ed338f1b ("clk: at91: fix recalc_rate implementation of PLL
> driver") but the bug was later re-introduced by 1bdf02326b71 ("clk:
> at91: make use of syscon/regmap internally").
> "
>
>
> The following comment and the changelog should be placed after the
> '---' line, so that it's not part of the commit message.
>
> > Thank you for bearing with me about this Boris.
> >
> > Changes since V2:
> > Removed all logging/debug messages I added
> > > Comment by Boris Brezillon about my fix being wrong addressed
> > Changes since V1:
> > Added patch set cover letter
> > Shortened lines which were over >80 characters long
> > > Comment by Greg Kroah-Hartman about "from" field in email addressed
> > > Comment by Alan Stern about redundant debug lines addressed
> >
>
> You should add Fixes and Cc-stable tags so that the fix is backported
> to stable branches:
>
> Fixes: 1bdf02326b71 ("clk: at91: make use of syscon/regmap internally)
> Cc: <stable@vger.kernel.org>
>
> > Signed-off-by: Marcin Ziemianowicz <marcin@ziemianowicz.com>
> > ---
> > drivers/clk/at91/clk-pll.c | 13 +------------
> > 1 file changed, 1 insertion(+), 12 deletions(-)
> >
> > diff --git a/drivers/clk/at91/clk-pll.c b/drivers/clk/at91/clk-pll.c
> > index 7d3223fc..cc6e0364 100644
> > --- a/drivers/clk/at91/clk-pll.c
> > +++ b/drivers/clk/at91/clk-pll.c
> > @@ -132,19 +132,8 @@ static unsigned long clk_pll_recalc_rate(struct clk_hw *hw,
> > unsigned long parent_rate)
> > {
> > struct clk_pll *pll = to_clk_pll(hw);
> > - unsigned int pllr;
> > - u16 mul;
> > - u8 div;
> > -
> > - regmap_read(pll->regmap, PLL_REG(pll->id), &pllr);
> > -
> > - div = PLL_DIV(pllr);
> > - mul = PLL_MUL(pllr, pll->layout);
> > -
> > - if (!div || !mul)
> > - return 0;
> >
> > - return (parent_rate / div) * (mul + 1);
> > + return return (parent_rate / pll->div) * (pll->mul + 1);
Oops, one too many return as reported by kbuild test robot.
>
> The fix looks good. Let me know if you struggle with git
> format-patch/send-email and I'll try to help you (or send the patch for
> you if you don't care learning the process, but I think it's better if
> you learn how to submit patches).
>
> Thanks,
>
> Boris
>
> > }
> >
> > static long clk_pll_get_best_div_mul(struct clk_pll *pll, unsigned long rate,
>
^ permalink raw reply [flat|nested] 12+ messages in thread
* [PATCH v3] clk: at91: PLL recalc_rate() now using cached MUL+DIV values
@ 2018-04-29 13:19 ` Boris Brezillon
0 siblings, 0 replies; 12+ messages in thread
From: Boris Brezillon @ 2018-04-29 13:19 UTC (permalink / raw)
To: linux-arm-kernel
On Sun, 29 Apr 2018 15:17:10 +0200
Boris Brezillon <boris.brezillon@bootlin.com> wrote:
> Hi Marcin,
>
> On Fri, 27 Apr 2018 13:56:09 -0400
> Marcin Ziemianowicz <marcin@ziemianowicz.com> wrote:
>
> > Stephen Boyd <sboyd@kernel.org>,
> > linux-clk at vger.kernel.org,
> > linux-arm-kernel at lists.infradead.org,
> > linux-kernel at vger.kernel.org
> > Bcc:
> > Subject: [PATCH v3] clk: at91: PLL recalc_rate() now using cached MUL and DIV
> > values
> > Reply-To:
>
> Hm, I don't know how you prepared and sent your patch, but you shouldn't
> have these fields in the body of your email. Please use git format-patch
> to prepare the patch and then git send-email to send it.
>
> >
> > 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. Based on a logic sniffer, I saw the USB bus was running
> > at half speed.
> >
> > The PLL code uses cached MUL and DIV values which get set in set_rate()
> > and applied in prepare(), but the recalc_rate() function instead
> > queries the hardware instead of using these cached values. Therefore,
> > if recalc_rate() is called between a set_rate() and prepare(), the
> > wrong frequency is calculated and later the USB clock divider for the
> > SAM9N12 SOC will be configured for an incorrect clock.
> >
> > In my case, the PLL hardware was set to 96 Mhz before the OHCI
> > driver loads, and therefore the usb clock divider was being set
> > to /2 even though the OHCI driver set the PLL to 48 Mhz.
> >
> > As an alternative explanation, I noticed this was fixed in the past:
> > http://lists.infradead.org/pipermail/linux-arm-kernel/2014-September/283502.html
> > but was later changed back via a large patch (maybe by mistake?):
> > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=1bdf02326b71eae7e9b4b335b881856aaf9d1af6
>
> Yep, probably by mistake. I started this rework long before it has been
> submitted to the ML, so I probably messed something up when rebasing.
>
> Also, prefer commit IDs to links to the ML archive. The above would
> sentence would give:
>
> "
> As an alternative explanation, I noticed this was fixed in the past by
> 87e2ed338f1b ("clk: at91: fix recalc_rate implementation of PLL
> driver") but the bug was later re-introduced by 1bdf02326b71 ("clk:
> at91: make use of syscon/regmap internally").
> "
>
>
> The following comment and the changelog should be placed after the
> '---' line, so that it's not part of the commit message.
>
> > Thank you for bearing with me about this Boris.
> >
> > Changes since V2:
> > Removed all logging/debug messages I added
> > > Comment by Boris Brezillon about my fix being wrong addressed
> > Changes since V1:
> > Added patch set cover letter
> > Shortened lines which were over >80 characters long
> > > Comment by Greg Kroah-Hartman about "from" field in email addressed
> > > Comment by Alan Stern about redundant debug lines addressed
> >
>
> You should add Fixes and Cc-stable tags so that the fix is backported
> to stable branches:
>
> Fixes: 1bdf02326b71 ("clk: at91: make use of syscon/regmap internally)
> Cc: <stable@vger.kernel.org>
>
> > Signed-off-by: Marcin Ziemianowicz <marcin@ziemianowicz.com>
> > ---
> > drivers/clk/at91/clk-pll.c | 13 +------------
> > 1 file changed, 1 insertion(+), 12 deletions(-)
> >
> > diff --git a/drivers/clk/at91/clk-pll.c b/drivers/clk/at91/clk-pll.c
> > index 7d3223fc..cc6e0364 100644
> > --- a/drivers/clk/at91/clk-pll.c
> > +++ b/drivers/clk/at91/clk-pll.c
> > @@ -132,19 +132,8 @@ static unsigned long clk_pll_recalc_rate(struct clk_hw *hw,
> > unsigned long parent_rate)
> > {
> > struct clk_pll *pll = to_clk_pll(hw);
> > - unsigned int pllr;
> > - u16 mul;
> > - u8 div;
> > -
> > - regmap_read(pll->regmap, PLL_REG(pll->id), &pllr);
> > -
> > - div = PLL_DIV(pllr);
> > - mul = PLL_MUL(pllr, pll->layout);
> > -
> > - if (!div || !mul)
> > - return 0;
> >
> > - return (parent_rate / div) * (mul + 1);
> > + return return (parent_rate / pll->div) * (pll->mul + 1);
Oops, one too many return as reported by kbuild test robot.
>
> The fix looks good. Let me know if you struggle with git
> format-patch/send-email and I'll try to help you (or send the patch for
> you if you don't care learning the process, but I think it's better if
> you learn how to submit patches).
>
> Thanks,
>
> Boris
>
> > }
> >
> > static long clk_pll_get_best_div_mul(struct clk_pll *pll, unsigned long rate,
>
^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [PATCH v3] clk: at91: PLL recalc_rate() now using cached MUL+DIV values
2018-04-29 13:19 ` Boris Brezillon
@ 2018-04-29 15:25 ` Marcin Ziemianowicz
-1 siblings, 0 replies; 12+ messages in thread
From: Marcin Ziemianowicz @ 2018-04-29 15:25 UTC (permalink / raw)
To: Boris Brezillon
Cc: Boris Brezillon, Nicolas Ferre, Alexandre Belloni,
Michael Turquette, Stephen Boyd, linux-clk, linux-arm-kernel,
linux-kernel
On Sun, Apr 29, 2018 at 03:19:35PM +0200, Boris Brezillon wrote:
> On Sun, 29 Apr 2018 15:17:10 +0200
> Boris Brezillon <boris.brezillon@bootlin.com> wrote:
>
> > Hi Marcin,
> >
> > On Fri, 27 Apr 2018 13:56:09 -0400
> > Marcin Ziemianowicz <marcin@ziemianowicz.com> wrote:
> >
> > > Stephen Boyd <sboyd@kernel.org>,
> > > linux-clk@vger.kernel.org,
> > > linux-arm-kernel@lists.infradead.org,
> > > linux-kernel@vger.kernel.org
> > > Bcc:
> > > Subject: [PATCH v3] clk: at91: PLL recalc_rate() now using cached MUL and DIV
> > > values
> > > Reply-To:
> >
> > Hm, I don't know how you prepared and sent your patch, but you shouldn't
> > have these fields in the body of your email. Please use git format-patch
> > to prepare the patch and then git send-email to send it.
> >
> > >
> > > 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. Based on a logic sniffer, I saw the USB bus was running
> > > at half speed.
> > >
> > > The PLL code uses cached MUL and DIV values which get set in set_rate()
> > > and applied in prepare(), but the recalc_rate() function instead
> > > queries the hardware instead of using these cached values. Therefore,
> > > if recalc_rate() is called between a set_rate() and prepare(), the
> > > wrong frequency is calculated and later the USB clock divider for the
> > > SAM9N12 SOC will be configured for an incorrect clock.
> > >
> > > In my case, the PLL hardware was set to 96 Mhz before the OHCI
> > > driver loads, and therefore the usb clock divider was being set
> > > to /2 even though the OHCI driver set the PLL to 48 Mhz.
> > >
> > > As an alternative explanation, I noticed this was fixed in the past:
> > > http://lists.infradead.org/pipermail/linux-arm-kernel/2014-September/283502.html
> > > but was later changed back via a large patch (maybe by mistake?):
> > > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=1bdf02326b71eae7e9b4b335b881856aaf9d1af6
> >
> > Yep, probably by mistake. I started this rework long before it has been
> > submitted to the ML, so I probably messed something up when rebasing.
> >
> > Also, prefer commit IDs to links to the ML archive. The above would
> > sentence would give:
> >
> > "
> > As an alternative explanation, I noticed this was fixed in the past by
> > 87e2ed338f1b ("clk: at91: fix recalc_rate implementation of PLL
> > driver") but the bug was later re-introduced by 1bdf02326b71 ("clk:
> > at91: make use of syscon/regmap internally").
> > "
> >
> >
> > The following comment and the changelog should be placed after the
> > '---' line, so that it's not part of the commit message.
> >
> > > Thank you for bearing with me about this Boris.
> > >
> > > Changes since V2:
> > > Removed all logging/debug messages I added
> > > > Comment by Boris Brezillon about my fix being wrong addressed
> > > Changes since V1:
> > > Added patch set cover letter
> > > Shortened lines which were over >80 characters long
> > > > Comment by Greg Kroah-Hartman about "from" field in email addressed
> > > > Comment by Alan Stern about redundant debug lines addressed
> > >
> >
> > You should add Fixes and Cc-stable tags so that the fix is backported
> > to stable branches:
> >
> > Fixes: 1bdf02326b71 ("clk: at91: make use of syscon/regmap internally)
> > Cc: <stable@vger.kernel.org>
> >
> > > Signed-off-by: Marcin Ziemianowicz <marcin@ziemianowicz.com>
> > > ---
> > > drivers/clk/at91/clk-pll.c | 13 +------------
> > > 1 file changed, 1 insertion(+), 12 deletions(-)
> > >
> > > diff --git a/drivers/clk/at91/clk-pll.c b/drivers/clk/at91/clk-pll.c
> > > index 7d3223fc..cc6e0364 100644
> > > --- a/drivers/clk/at91/clk-pll.c
> > > +++ b/drivers/clk/at91/clk-pll.c
> > > @@ -132,19 +132,8 @@ static unsigned long clk_pll_recalc_rate(struct clk_hw *hw,
> > > unsigned long parent_rate)
> > > {
> > > struct clk_pll *pll = to_clk_pll(hw);
> > > - unsigned int pllr;
> > > - u16 mul;
> > > - u8 div;
> > > -
> > > - regmap_read(pll->regmap, PLL_REG(pll->id), &pllr);
> > > -
> > > - div = PLL_DIV(pllr);
> > > - mul = PLL_MUL(pllr, pll->layout);
> > > -
> > > - if (!div || !mul)
> > > - return 0;
> > >
> > > - return (parent_rate / div) * (mul + 1);
> > > + return return (parent_rate / pll->div) * (pll->mul + 1);
>
> Oops, one too many return as reported by kbuild test robot.
That's what I get for bug fixing in a buildroot generated kernel
directory and then copying it over to a new git clone'd kernel directory
by hand. I will fix this in addition to all the problems you raised in
the earlier email. Thank you again!
>
> >
> > The fix looks good. Let me know if you struggle with git
> > format-patch/send-email and I'll try to help you (or send the patch for
> > you if you don't care learning the process, but I think it's better if
> > you learn how to submit patches).
> >
> > Thanks,
> >
> > Boris
> >
> > > }
> > >
> > > static long clk_pll_get_best_div_mul(struct clk_pll *pll, unsigned long rate,
> >
>
^ permalink raw reply [flat|nested] 12+ messages in thread
* [PATCH v3] clk: at91: PLL recalc_rate() now using cached MUL+DIV values
@ 2018-04-29 15:25 ` Marcin Ziemianowicz
0 siblings, 0 replies; 12+ messages in thread
From: Marcin Ziemianowicz @ 2018-04-29 15:25 UTC (permalink / raw)
To: linux-arm-kernel
On Sun, Apr 29, 2018 at 03:19:35PM +0200, Boris Brezillon wrote:
> On Sun, 29 Apr 2018 15:17:10 +0200
> Boris Brezillon <boris.brezillon@bootlin.com> wrote:
>
> > Hi Marcin,
> >
> > On Fri, 27 Apr 2018 13:56:09 -0400
> > Marcin Ziemianowicz <marcin@ziemianowicz.com> wrote:
> >
> > > Stephen Boyd <sboyd@kernel.org>,
> > > linux-clk at vger.kernel.org,
> > > linux-arm-kernel at lists.infradead.org,
> > > linux-kernel at vger.kernel.org
> > > Bcc:
> > > Subject: [PATCH v3] clk: at91: PLL recalc_rate() now using cached MUL and DIV
> > > values
> > > Reply-To:
> >
> > Hm, I don't know how you prepared and sent your patch, but you shouldn't
> > have these fields in the body of your email. Please use git format-patch
> > to prepare the patch and then git send-email to send it.
> >
> > >
> > > 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. Based on a logic sniffer, I saw the USB bus was running
> > > at half speed.
> > >
> > > The PLL code uses cached MUL and DIV values which get set in set_rate()
> > > and applied in prepare(), but the recalc_rate() function instead
> > > queries the hardware instead of using these cached values. Therefore,
> > > if recalc_rate() is called between a set_rate() and prepare(), the
> > > wrong frequency is calculated and later the USB clock divider for the
> > > SAM9N12 SOC will be configured for an incorrect clock.
> > >
> > > In my case, the PLL hardware was set to 96 Mhz before the OHCI
> > > driver loads, and therefore the usb clock divider was being set
> > > to /2 even though the OHCI driver set the PLL to 48 Mhz.
> > >
> > > As an alternative explanation, I noticed this was fixed in the past:
> > > http://lists.infradead.org/pipermail/linux-arm-kernel/2014-September/283502.html
> > > but was later changed back via a large patch (maybe by mistake?):
> > > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=1bdf02326b71eae7e9b4b335b881856aaf9d1af6
> >
> > Yep, probably by mistake. I started this rework long before it has been
> > submitted to the ML, so I probably messed something up when rebasing.
> >
> > Also, prefer commit IDs to links to the ML archive. The above would
> > sentence would give:
> >
> > "
> > As an alternative explanation, I noticed this was fixed in the past by
> > 87e2ed338f1b ("clk: at91: fix recalc_rate implementation of PLL
> > driver") but the bug was later re-introduced by 1bdf02326b71 ("clk:
> > at91: make use of syscon/regmap internally").
> > "
> >
> >
> > The following comment and the changelog should be placed after the
> > '---' line, so that it's not part of the commit message.
> >
> > > Thank you for bearing with me about this Boris.
> > >
> > > Changes since V2:
> > > Removed all logging/debug messages I added
> > > > Comment by Boris Brezillon about my fix being wrong addressed
> > > Changes since V1:
> > > Added patch set cover letter
> > > Shortened lines which were over >80 characters long
> > > > Comment by Greg Kroah-Hartman about "from" field in email addressed
> > > > Comment by Alan Stern about redundant debug lines addressed
> > >
> >
> > You should add Fixes and Cc-stable tags so that the fix is backported
> > to stable branches:
> >
> > Fixes: 1bdf02326b71 ("clk: at91: make use of syscon/regmap internally)
> > Cc: <stable@vger.kernel.org>
> >
> > > Signed-off-by: Marcin Ziemianowicz <marcin@ziemianowicz.com>
> > > ---
> > > drivers/clk/at91/clk-pll.c | 13 +------------
> > > 1 file changed, 1 insertion(+), 12 deletions(-)
> > >
> > > diff --git a/drivers/clk/at91/clk-pll.c b/drivers/clk/at91/clk-pll.c
> > > index 7d3223fc..cc6e0364 100644
> > > --- a/drivers/clk/at91/clk-pll.c
> > > +++ b/drivers/clk/at91/clk-pll.c
> > > @@ -132,19 +132,8 @@ static unsigned long clk_pll_recalc_rate(struct clk_hw *hw,
> > > unsigned long parent_rate)
> > > {
> > > struct clk_pll *pll = to_clk_pll(hw);
> > > - unsigned int pllr;
> > > - u16 mul;
> > > - u8 div;
> > > -
> > > - regmap_read(pll->regmap, PLL_REG(pll->id), &pllr);
> > > -
> > > - div = PLL_DIV(pllr);
> > > - mul = PLL_MUL(pllr, pll->layout);
> > > -
> > > - if (!div || !mul)
> > > - return 0;
> > >
> > > - return (parent_rate / div) * (mul + 1);
> > > + return return (parent_rate / pll->div) * (pll->mul + 1);
>
> Oops, one too many return as reported by kbuild test robot.
That's what I get for bug fixing in a buildroot generated kernel
directory and then copying it over to a new git clone'd kernel directory
by hand. I will fix this in addition to all the problems you raised in
the earlier email. Thank you again!
>
> >
> > The fix looks good. Let me know if you struggle with git
> > format-patch/send-email and I'll try to help you (or send the patch for
> > you if you don't care learning the process, but I think it's better if
> > you learn how to submit patches).
> >
> > Thanks,
> >
> > Boris
> >
> > > }
> > >
> > > static long clk_pll_get_best_div_mul(struct clk_pll *pll, unsigned long rate,
> >
>
^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [PATCH v3] clk: at91: PLL recalc_rate() now using cached MUL+DIV values
2018-04-29 13:17 ` Boris Brezillon
@ 2018-04-29 15:22 ` Marcin Ziemianowicz
-1 siblings, 0 replies; 12+ messages in thread
From: Marcin Ziemianowicz @ 2018-04-29 15:22 UTC (permalink / raw)
To: Boris Brezillon
Cc: Boris Brezillon, Nicolas Ferre, Alexandre Belloni,
Michael Turquette, Stephen Boyd, linux-clk, linux-arm-kernel,
linux-kernel
On Sun, Apr 29, 2018 at 03:17:10PM +0200, Boris Brezillon wrote:
> Hi Marcin,
>
> On Fri, 27 Apr 2018 13:56:09 -0400
> Marcin Ziemianowicz <marcin@ziemianowicz.com> wrote:
>
> > Stephen Boyd <sboyd@kernel.org>,
> > linux-clk@vger.kernel.org,
> > linux-arm-kernel@lists.infradead.org,
> > linux-kernel@vger.kernel.org
> > Bcc:
> > Subject: [PATCH v3] clk: at91: PLL recalc_rate() now using cached MUL and DIV
> > values
> > Reply-To:
>
> Hm, I don't know how you prepared and sent your patch, but you shouldn't
> have these fields in the body of your email. Please use git format-patch
> to prepare the patch and then git send-email to send it.
I have been using Mutt this entire time with the idea of being able to use
Mutt for both sending the patch and replying to emails, but I am still
fumbling around with this (as you can see). I used git format-patch HEAD^
and I think I additionally bungled something when using Mutt. I will try
git send-email instead since it seems less error prone on my end.
>
> >
> > 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. Based on a logic sniffer, I saw the USB bus was running
> > at half speed.
> >
> > The PLL code uses cached MUL and DIV values which get set in set_rate()
> > and applied in prepare(), but the recalc_rate() function instead
> > queries the hardware instead of using these cached values. Therefore,
> > if recalc_rate() is called between a set_rate() and prepare(), the
> > wrong frequency is calculated and later the USB clock divider for the
> > SAM9N12 SOC will be configured for an incorrect clock.
> >
> > In my case, the PLL hardware was set to 96 Mhz before the OHCI
> > driver loads, and therefore the usb clock divider was being set
> > to /2 even though the OHCI driver set the PLL to 48 Mhz.
> >
> > As an alternative explanation, I noticed this was fixed in the past:
> > http://lists.infradead.org/pipermail/linux-arm-kernel/2014-September/283502.html
> > but was later changed back via a large patch (maybe by mistake?):
> > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=1bdf02326b71eae7e9b4b335b881856aaf9d1af6
>
> Yep, probably by mistake. I started this rework long before it has been
> submitted to the ML, so I probably messed something up when rebasing.
>
Ah, it happens I guess. 99 little bugs in the code, 99 litle bugs. Take
one down, patch it around, 117 little bugs in the code. ;)
> Also, prefer commit IDs to links to the ML archive. The above would
> sentence would give:
>
> "
> As an alternative explanation, I noticed this was fixed in the past by
> 87e2ed338f1b ("clk: at91: fix recalc_rate implementation of PLL
> driver") but the bug was later re-introduced by 1bdf02326b71 ("clk:
> at91: make use of syscon/regmap internally").
> "
>
Ah, I was wondering what the best way is to reference old commits.
Thank you, will do!
>
> The following comment and the changelog should be placed after the
> '---' line, so that it's not part of the commit message.
>
> > Thank you for bearing with me about this Boris.
> >
> > Changes since V2:
> > Removed all logging/debug messages I added
> > > Comment by Boris Brezillon about my fix being wrong addressed
> > Changes since V1:
> > Added patch set cover letter
> > Shortened lines which were over >80 characters long
> > > Comment by Greg Kroah-Hartman about "from" field in email addressed
> > > Comment by Alan Stern about redundant debug lines addressed
> >
>
> You should add Fixes and Cc-stable tags so that the fix is backported
> to stable branches:
>
> Fixes: 1bdf02326b71 ("clk: at91: make use of syscon/regmap internally)
> Cc: <stable@vger.kernel.org>
>
> > Signed-off-by: Marcin Ziemianowicz <marcin@ziemianowicz.com>
> > ---
> > drivers/clk/at91/clk-pll.c | 13 +------------
> > 1 file changed, 1 insertion(+), 12 deletions(-)
> >
> > diff --git a/drivers/clk/at91/clk-pll.c b/drivers/clk/at91/clk-pll.c
> > index 7d3223fc..cc6e0364 100644
> > --- a/drivers/clk/at91/clk-pll.c
> > +++ b/drivers/clk/at91/clk-pll.c
> > @@ -132,19 +132,8 @@ static unsigned long clk_pll_recalc_rate(struct clk_hw *hw,
> > unsigned long parent_rate)
> > {
> > struct clk_pll *pll = to_clk_pll(hw);
> > - unsigned int pllr;
> > - u16 mul;
> > - u8 div;
> > -
> > - regmap_read(pll->regmap, PLL_REG(pll->id), &pllr);
> > -
> > - div = PLL_DIV(pllr);
> > - mul = PLL_MUL(pllr, pll->layout);
> > -
> > - if (!div || !mul)
> > - return 0;
> >
> > - return (parent_rate / div) * (mul + 1);
> > + return return (parent_rate / pll->div) * (pll->mul + 1);
>
> The fix looks good. Let me know if you struggle with git
> format-patch/send-email and I'll try to help you (or send the patch for
> you if you don't care learning the process, but I think it's better if
> you learn how to submit patches).
>
I definitely do want to learn how to do this myself, but thank you for the
offer! I just hope I am not taking up too much of your and others time with
me bumbling around like this.
> Thanks,
>
> Boris
>
> > }
> >
> > static long clk_pll_get_best_div_mul(struct clk_pll *pll, unsigned long rate,
>
^ permalink raw reply [flat|nested] 12+ messages in thread
* [PATCH v3] clk: at91: PLL recalc_rate() now using cached MUL+DIV values
@ 2018-04-29 15:22 ` Marcin Ziemianowicz
0 siblings, 0 replies; 12+ messages in thread
From: Marcin Ziemianowicz @ 2018-04-29 15:22 UTC (permalink / raw)
To: linux-arm-kernel
On Sun, Apr 29, 2018 at 03:17:10PM +0200, Boris Brezillon wrote:
> Hi Marcin,
>
> On Fri, 27 Apr 2018 13:56:09 -0400
> Marcin Ziemianowicz <marcin@ziemianowicz.com> wrote:
>
> > Stephen Boyd <sboyd@kernel.org>,
> > linux-clk at vger.kernel.org,
> > linux-arm-kernel at lists.infradead.org,
> > linux-kernel at vger.kernel.org
> > Bcc:
> > Subject: [PATCH v3] clk: at91: PLL recalc_rate() now using cached MUL and DIV
> > values
> > Reply-To:
>
> Hm, I don't know how you prepared and sent your patch, but you shouldn't
> have these fields in the body of your email. Please use git format-patch
> to prepare the patch and then git send-email to send it.
I have been using Mutt this entire time with the idea of being able to use
Mutt for both sending the patch and replying to emails, but I am still
fumbling around with this (as you can see). I used git format-patch HEAD^
and I think I additionally bungled something when using Mutt. I will try
git send-email instead since it seems less error prone on my end.
>
> >
> > 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. Based on a logic sniffer, I saw the USB bus was running
> > at half speed.
> >
> > The PLL code uses cached MUL and DIV values which get set in set_rate()
> > and applied in prepare(), but the recalc_rate() function instead
> > queries the hardware instead of using these cached values. Therefore,
> > if recalc_rate() is called between a set_rate() and prepare(), the
> > wrong frequency is calculated and later the USB clock divider for the
> > SAM9N12 SOC will be configured for an incorrect clock.
> >
> > In my case, the PLL hardware was set to 96 Mhz before the OHCI
> > driver loads, and therefore the usb clock divider was being set
> > to /2 even though the OHCI driver set the PLL to 48 Mhz.
> >
> > As an alternative explanation, I noticed this was fixed in the past:
> > http://lists.infradead.org/pipermail/linux-arm-kernel/2014-September/283502.html
> > but was later changed back via a large patch (maybe by mistake?):
> > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=1bdf02326b71eae7e9b4b335b881856aaf9d1af6
>
> Yep, probably by mistake. I started this rework long before it has been
> submitted to the ML, so I probably messed something up when rebasing.
>
Ah, it happens I guess. 99 little bugs in the code, 99 litle bugs. Take
one down, patch it around, 117 little bugs in the code. ;)
> Also, prefer commit IDs to links to the ML archive. The above would
> sentence would give:
>
> "
> As an alternative explanation, I noticed this was fixed in the past by
> 87e2ed338f1b ("clk: at91: fix recalc_rate implementation of PLL
> driver") but the bug was later re-introduced by 1bdf02326b71 ("clk:
> at91: make use of syscon/regmap internally").
> "
>
Ah, I was wondering what the best way is to reference old commits.
Thank you, will do!
>
> The following comment and the changelog should be placed after the
> '---' line, so that it's not part of the commit message.
>
> > Thank you for bearing with me about this Boris.
> >
> > Changes since V2:
> > Removed all logging/debug messages I added
> > > Comment by Boris Brezillon about my fix being wrong addressed
> > Changes since V1:
> > Added patch set cover letter
> > Shortened lines which were over >80 characters long
> > > Comment by Greg Kroah-Hartman about "from" field in email addressed
> > > Comment by Alan Stern about redundant debug lines addressed
> >
>
> You should add Fixes and Cc-stable tags so that the fix is backported
> to stable branches:
>
> Fixes: 1bdf02326b71 ("clk: at91: make use of syscon/regmap internally)
> Cc: <stable@vger.kernel.org>
>
> > Signed-off-by: Marcin Ziemianowicz <marcin@ziemianowicz.com>
> > ---
> > drivers/clk/at91/clk-pll.c | 13 +------------
> > 1 file changed, 1 insertion(+), 12 deletions(-)
> >
> > diff --git a/drivers/clk/at91/clk-pll.c b/drivers/clk/at91/clk-pll.c
> > index 7d3223fc..cc6e0364 100644
> > --- a/drivers/clk/at91/clk-pll.c
> > +++ b/drivers/clk/at91/clk-pll.c
> > @@ -132,19 +132,8 @@ static unsigned long clk_pll_recalc_rate(struct clk_hw *hw,
> > unsigned long parent_rate)
> > {
> > struct clk_pll *pll = to_clk_pll(hw);
> > - unsigned int pllr;
> > - u16 mul;
> > - u8 div;
> > -
> > - regmap_read(pll->regmap, PLL_REG(pll->id), &pllr);
> > -
> > - div = PLL_DIV(pllr);
> > - mul = PLL_MUL(pllr, pll->layout);
> > -
> > - if (!div || !mul)
> > - return 0;
> >
> > - return (parent_rate / div) * (mul + 1);
> > + return return (parent_rate / pll->div) * (pll->mul + 1);
>
> The fix looks good. Let me know if you struggle with git
> format-patch/send-email and I'll try to help you (or send the patch for
> you if you don't care learning the process, but I think it's better if
> you learn how to submit patches).
>
I definitely do want to learn how to do this myself, but thank you for the
offer! I just hope I am not taking up too much of your and others time with
me bumbling around like this.
> Thanks,
>
> Boris
>
> > }
> >
> > static long clk_pll_get_best_div_mul(struct clk_pll *pll, unsigned long rate,
>
^ permalink raw reply [flat|nested] 12+ messages in thread