| Message ID | 20220119002438.106079-6-sean.anderson@seco.com |
|---|---|
| State | Superseded |
| Headers | show |
| Series | [v2,1/7] dt-bindings: usb: dwc3: Deprecate snps,ref-clock-period-ns | expand |
Sean Anderson wrote: > This property allows setting the reference clock frequency properly for > ACPI-based systems. It is not documented under dt-bindings, since it is > not intended for use on DT-based systems. DT-based systems should use > the clocks property instead. > > Frequency is preferred over period since it has greater precision when > used in calculations. > > Signed-off-by: Sean Anderson <sean.anderson@seco.com> > --- > > Changes in v2: > - New > > drivers/usb/dwc3/core.c | 6 ++++-- > drivers/usb/dwc3/core.h | 4 +++- > 2 files changed, 7 insertions(+), 3 deletions(-) > > diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c > index 883e119377f0..5f3dc5f6cbcb 100644 > --- a/drivers/usb/dwc3/core.c > +++ b/drivers/usb/dwc3/core.c > @@ -350,8 +350,8 @@ static void dwc3_ref_clk_period(struct dwc3 *dwc) > u32 reg; > unsigned long decr, fladj, rate, period; > > - if (dwc->ref_clk) { > - rate = clk_get_rate(dwc->ref_clk); > + if (dwc->ref_clk || dwc->ref_clk_freq) { > + rate = clk_get_rate(dwc->ref_clk) ?: dwc->ref_clk_freq; > if (!rate) > return; > period = NSEC_PER_SEC / rate; > @@ -1492,6 +1492,8 @@ static void dwc3_get_properties(struct dwc3 *dwc) > &dwc->fladj); > device_property_read_u32(dev, "snps,ref-clock-period-ns", > &dwc->ref_clk_per); > + device_property_read_u32(dev, "snps,ref-clock-frequency-hz", > + &dwc->ref_clk_freq); Please also document in dwc3 DT file whenever we add a new property. Thanks, Thinh > > dwc->dis_metastability_quirk = device_property_read_bool(dev, > "snps,dis_metastability_quirk"); > diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h > index eb9c1efced05..00a792459fec 100644 > --- a/drivers/usb/dwc3/core.h > +++ b/drivers/usb/dwc3/core.h > @@ -988,7 +988,8 @@ struct dwc3_scratchpad_array { > * @regs: base address for our registers > * @regs_size: address space size > * @fladj: frame length adjustment > - * @ref_clk_per: reference clock period configuration > + * @ref_clk_per: reference clock period; deprecated in favor of @ref_clk_freq > + * @ref_clk_freq: reference clock frequency to use if @ref_clk is missing > * @irq_gadget: peripheral controller's IRQ number > * @otg_irq: IRQ number for OTG IRQs > * @current_otg_role: current role of operation while using the OTG block > @@ -1171,6 +1172,7 @@ struct dwc3 { > > u32 fladj; > u32 ref_clk_per; > + u32 ref_clk_freq; > u32 irq_gadget; > u32 otg_irq; > u32 current_otg_role;
On 1/24/22 6:07 PM, Sean Anderson wrote: > On 1/24/22 5:44 PM, Thinh Nguyen wrote: >> Sean Anderson wrote: >>> This property allows setting the reference clock frequency properly for >>> ACPI-based systems. It is not documented under dt-bindings, since it is >>> not intended for use on DT-based systems. DT-based systems should use >>> the clocks property instead. >>> >>> Frequency is preferred over period since it has greater precision when >>> used in calculations. >>> >>> Signed-off-by: Sean Anderson <sean.anderson@seco.com> >>> --- >>> >>> Changes in v2: >>> - New >>> >>> drivers/usb/dwc3/core.c | 6 ++++-- >>> drivers/usb/dwc3/core.h | 4 +++- >>> 2 files changed, 7 insertions(+), 3 deletions(-) >>> >>> diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c >>> index 883e119377f0..5f3dc5f6cbcb 100644 >>> --- a/drivers/usb/dwc3/core.c >>> +++ b/drivers/usb/dwc3/core.c >>> @@ -350,8 +350,8 @@ static void dwc3_ref_clk_period(struct dwc3 *dwc) >>> u32 reg; >>> unsigned long decr, fladj, rate, period; >>> >>> - if (dwc->ref_clk) { >>> - rate = clk_get_rate(dwc->ref_clk); >>> + if (dwc->ref_clk || dwc->ref_clk_freq) { >>> + rate = clk_get_rate(dwc->ref_clk) ?: dwc->ref_clk_freq; >>> if (!rate) >>> return; >>> period = NSEC_PER_SEC / rate; >>> @@ -1492,6 +1492,8 @@ static void dwc3_get_properties(struct dwc3 *dwc) >>> &dwc->fladj); >>> device_property_read_u32(dev, "snps,ref-clock-period-ns", >>> &dwc->ref_clk_per); >>> + device_property_read_u32(dev, "snps,ref-clock-frequency-hz", >>> + &dwc->ref_clk_freq); >> >> Please also document in dwc3 DT file whenever we add a new property. > > This is intentionally undocumented, as noted in the commit message. > Rob Herring has said that dt-bindings should only document properties > intended for device-tree. context: https://lore.kernel.org/all/20181219202734.GA31178@bogus/ This patch was later resubmitted as 24bc6e68efa0 ("serial: sc16is7xx: Respect clock-frequency property") without the dt-bindings documentation. +CC Rob if he wants to comment on this specific situation. --Sean
diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c index 883e119377f0..5f3dc5f6cbcb 100644 --- a/drivers/usb/dwc3/core.c +++ b/drivers/usb/dwc3/core.c @@ -350,8 +350,8 @@ static void dwc3_ref_clk_period(struct dwc3 *dwc) u32 reg; unsigned long decr, fladj, rate, period; - if (dwc->ref_clk) { - rate = clk_get_rate(dwc->ref_clk); + if (dwc->ref_clk || dwc->ref_clk_freq) { + rate = clk_get_rate(dwc->ref_clk) ?: dwc->ref_clk_freq; if (!rate) return; period = NSEC_PER_SEC / rate; @@ -1492,6 +1492,8 @@ static void dwc3_get_properties(struct dwc3 *dwc) &dwc->fladj); device_property_read_u32(dev, "snps,ref-clock-period-ns", &dwc->ref_clk_per); + device_property_read_u32(dev, "snps,ref-clock-frequency-hz", + &dwc->ref_clk_freq); dwc->dis_metastability_quirk = device_property_read_bool(dev, "snps,dis_metastability_quirk"); diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h index eb9c1efced05..00a792459fec 100644 --- a/drivers/usb/dwc3/core.h +++ b/drivers/usb/dwc3/core.h @@ -988,7 +988,8 @@ struct dwc3_scratchpad_array { * @regs: base address for our registers * @regs_size: address space size * @fladj: frame length adjustment - * @ref_clk_per: reference clock period configuration + * @ref_clk_per: reference clock period; deprecated in favor of @ref_clk_freq + * @ref_clk_freq: reference clock frequency to use if @ref_clk is missing * @irq_gadget: peripheral controller's IRQ number * @otg_irq: IRQ number for OTG IRQs * @current_otg_role: current role of operation while using the OTG block @@ -1171,6 +1172,7 @@ struct dwc3 { u32 fladj; u32 ref_clk_per; + u32 ref_clk_freq; u32 irq_gadget; u32 otg_irq; u32 current_otg_role;
This property allows setting the reference clock frequency properly for ACPI-based systems. It is not documented under dt-bindings, since it is not intended for use on DT-based systems. DT-based systems should use the clocks property instead. Frequency is preferred over period since it has greater precision when used in calculations. Signed-off-by: Sean Anderson <sean.anderson@seco.com> --- Changes in v2: - New drivers/usb/dwc3/core.c | 6 ++++-- drivers/usb/dwc3/core.h | 4 +++- 2 files changed, 7 insertions(+), 3 deletions(-)