Re: [PATCH 07/15] PCI: brcmstb: Add control of rescal reset
On 5/21/2020 2:48 PM, Jim Quinlan wrote:
> On Wed, May 20, 2020 at 3:27 AM Philipp Zabel wrote:
>>
>> Hi Jim,
>>
>> On Tue, May 19, 2020 at 04:34:05PM -0400, Jim Quinlan wrote:
>>> From: Jim Quinlan
>>>
>>> Some STB chips have a special purpose reset controller named
>>> RESCAL (reset calibration). This commit adds the control
>>> of RESCAL as well as the ability to start and stop its
>>> operation for PCIe HW.
>>>
>>> Signed-off-by: Jim Quinlan
>>> ---
>>> drivers/pci/controller/pcie-brcmstb.c | 81 ++-
>>> 1 file changed, 80 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/pci/controller/pcie-brcmstb.c
>>> b/drivers/pci/controller/pcie-brcmstb.c
>>> index 2c470104ba38..0787e8f6f7e5 100644
>>> --- a/drivers/pci/controller/pcie-brcmstb.c
>>> +++ b/drivers/pci/controller/pcie-brcmstb.c
>> [...]
>>> @@ -1100,6 +1164,21 @@ static int brcm_pcie_probe(struct platform_device
>>> *pdev)
>>> dev_err(>dev, "could not enable clock\n");
>>> return ret;
>>> }
>>> + pcie->rescal = devm_reset_control_get_shared(>dev, "rescal");
>>> + if (IS_ERR(pcie->rescal)) {
>>> + if (PTR_ERR(pcie->rescal) == -EPROBE_DEFER)
>>> + return -EPROBE_DEFER;
>>> + pcie->rescal = NULL;
>>
>> This is effectively an optional reset control, so it is better to use:
>> ↵
>> pcie->rescal = devm_reset_control_get_optional_shared(>dev,
>> "rescal");↵
>> if (IS_ERR(pcie->rescal))
>> return PTR_ERR(pcie->rescal);
>>
>>> + } else {
>>> + ret = reset_control_deassert(pcie->rescal);
>>> + if (ret)
>>> + dev_err(>dev, "failed to deassert 'rescal'\n");
>>> + }
>>
>> reset_control_* can handle rstc == NULL parameters for optional reset
>> controls, so this can be done unconditionally:
>>
>> ret = reset_control_deassert(pcie->rescal);↵
>> if (ret)↵
>> dev_err(>dev, "failed to deassert 'rescal'\n");↵
>>
>> Is rescal handled by the reset-brcmstb-rescal driver? Since that only
>> implements the .reset op, I would expect reset_control_reset() here.
> Where exactly? "reset.h" says that "Calling reset_control_rese()t is
> not allowed on a shared reset control." so I'm not sure why you would
> want me to invoke it.
Yes this is handled by drivers/reset/reset-brcmstb-rescal.c which only
implements a .reset() callback, what would be the appropriate API usage
here given that this is a shared reset between AHCI and PCIe, should
drivers/reset/reset-brcmstb-rescal.c not implement a .reset() callback
and .assert() callback instead?
>> Otherwise this looks like it'd be missing a reset_control_assert in
>> remove.
> I can add this.
> Thanks,
> Jim
>>
>> regards
>> Philipp
--
Florian
Re: [PATCH 07/15] PCI: brcmstb: Add control of rescal reset
On Wed, May 20, 2020 at 3:27 AM Philipp Zabel wrote:
>
> Hi Jim,
>
> On Tue, May 19, 2020 at 04:34:05PM -0400, Jim Quinlan wrote:
> > From: Jim Quinlan
> >
> > Some STB chips have a special purpose reset controller named
> > RESCAL (reset calibration). This commit adds the control
> > of RESCAL as well as the ability to start and stop its
> > operation for PCIe HW.
> >
> > Signed-off-by: Jim Quinlan
> > ---
> > drivers/pci/controller/pcie-brcmstb.c | 81 ++-
> > 1 file changed, 80 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/pci/controller/pcie-brcmstb.c
> > b/drivers/pci/controller/pcie-brcmstb.c
> > index 2c470104ba38..0787e8f6f7e5 100644
> > --- a/drivers/pci/controller/pcie-brcmstb.c
> > +++ b/drivers/pci/controller/pcie-brcmstb.c
> [...]
> > @@ -1100,6 +1164,21 @@ static int brcm_pcie_probe(struct platform_device
> > *pdev)
> > dev_err(>dev, "could not enable clock\n");
> > return ret;
> > }
> > + pcie->rescal = devm_reset_control_get_shared(>dev, "rescal");
> > + if (IS_ERR(pcie->rescal)) {
> > + if (PTR_ERR(pcie->rescal) == -EPROBE_DEFER)
> > + return -EPROBE_DEFER;
> > + pcie->rescal = NULL;
>
> This is effectively an optional reset control, so it is better to use:
> ↵
> pcie->rescal = devm_reset_control_get_optional_shared(>dev,
> "rescal");↵
> if (IS_ERR(pcie->rescal))
> return PTR_ERR(pcie->rescal);
>
> > + } else {
> > + ret = reset_control_deassert(pcie->rescal);
> > + if (ret)
> > + dev_err(>dev, "failed to deassert 'rescal'\n");
> > + }
>
> reset_control_* can handle rstc == NULL parameters for optional reset
> controls, so this can be done unconditionally:
>
> ret = reset_control_deassert(pcie->rescal);↵
> if (ret)↵
> dev_err(>dev, "failed to deassert 'rescal'\n");↵
>
> Is rescal handled by the reset-brcmstb-rescal driver? Since that only
> implements the .reset op, I would expect reset_control_reset() here.
Where exactly? "reset.h" says that "Calling reset_control_rese()t is
not allowed on a shared reset control." so I'm not sure why you would
want me to invoke it.
> Otherwise this looks like it'd be missing a reset_control_assert in
> remove.
I can add this.
Thanks,
Jim
>
> regards
> Philipp
Re: [PATCH 07/15] PCI: brcmstb: Add control of rescal reset
Hi Jim,
On Tue, May 19, 2020 at 04:34:05PM -0400, Jim Quinlan wrote:
> From: Jim Quinlan
>
> Some STB chips have a special purpose reset controller named
> RESCAL (reset calibration). This commit adds the control
> of RESCAL as well as the ability to start and stop its
> operation for PCIe HW.
>
> Signed-off-by: Jim Quinlan
> ---
> drivers/pci/controller/pcie-brcmstb.c | 81 ++-
> 1 file changed, 80 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/pci/controller/pcie-brcmstb.c
> b/drivers/pci/controller/pcie-brcmstb.c
> index 2c470104ba38..0787e8f6f7e5 100644
> --- a/drivers/pci/controller/pcie-brcmstb.c
> +++ b/drivers/pci/controller/pcie-brcmstb.c
[...]
> @@ -1100,6 +1164,21 @@ static int brcm_pcie_probe(struct platform_device
> *pdev)
> dev_err(>dev, "could not enable clock\n");
> return ret;
> }
> + pcie->rescal = devm_reset_control_get_shared(>dev, "rescal");
> + if (IS_ERR(pcie->rescal)) {
> + if (PTR_ERR(pcie->rescal) == -EPROBE_DEFER)
> + return -EPROBE_DEFER;
> + pcie->rescal = NULL;
This is effectively an optional reset control, so it is better to use:
↵
pcie->rescal = devm_reset_control_get_optional_shared(>dev,
"rescal");↵
if (IS_ERR(pcie->rescal))
return PTR_ERR(pcie->rescal);
> + } else {
> + ret = reset_control_deassert(pcie->rescal);
> + if (ret)
> + dev_err(>dev, "failed to deassert 'rescal'\n");
> + }
reset_control_* can handle rstc == NULL parameters for optional reset
controls, so this can be done unconditionally:
ret = reset_control_deassert(pcie->rescal);↵
if (ret)↵
dev_err(>dev, "failed to deassert 'rescal'\n");↵
Is rescal handled by the reset-brcmstb-rescal driver? Since that only
implements the .reset op, I would expect reset_control_reset() here.
Otherwise this looks like it'd be missing a reset_control_assert in
remove.
regards
Philipp
