Add compatible value for the T-Head TH1520 dwcmshc controller and add
thead,phy-pull-up property.
Signed-off-by: Drew Fustini <[email protected]>
---
Documentation/devicetree/bindings/mmc/snps,dwcmshc-sdhci.yaml | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/Documentation/devicetree/bindings/mmc/snps,dwcmshc-sdhci.yaml b/Documentation/devicetree/bindings/mmc/snps,dwcmshc-sdhci.yaml
index a43eb837f8da..46b768d46712 100644
--- a/Documentation/devicetree/bindings/mmc/snps,dwcmshc-sdhci.yaml
+++ b/Documentation/devicetree/bindings/mmc/snps,dwcmshc-sdhci.yaml
@@ -19,6 +19,7 @@ properties:
- rockchip,rk3568-dwcmshc
- rockchip,rk3588-dwcmshc
- snps,dwcmshc-sdhci
+ - thead,th1520-dwcmshc
reg:
maxItems: 1
@@ -60,6 +61,9 @@ properties:
description: Specify the number of delay for tx sampling.
$ref: /schemas/types.yaml#/definitions/uint8
+ thead,phy-pull-up:
+ description: Enable weak pull-up on PHY pads
+ type: boolean
required:
- compatible
--
2.34.1
Hey Drew,
On Thu, Sep 21, 2023 at 06:49:48PM -0700, Drew Fustini wrote:
> Add compatible value for the T-Head TH1520 dwcmshc controller and add
> thead,phy-pull-up property.
>
> Signed-off-by: Drew Fustini <[email protected]>
> ---
> Documentation/devicetree/bindings/mmc/snps,dwcmshc-sdhci.yaml | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/Documentation/devicetree/bindings/mmc/snps,dwcmshc-sdhci.yaml b/Documentation/devicetree/bindings/mmc/snps,dwcmshc-sdhci.yaml
> index a43eb837f8da..46b768d46712 100644
> --- a/Documentation/devicetree/bindings/mmc/snps,dwcmshc-sdhci.yaml
> +++ b/Documentation/devicetree/bindings/mmc/snps,dwcmshc-sdhci.yaml
> @@ -19,6 +19,7 @@ properties:
> - rockchip,rk3568-dwcmshc
> - rockchip,rk3588-dwcmshc
> - snps,dwcmshc-sdhci
> + - thead,th1520-dwcmshc
>
> reg:
> maxItems: 1
> @@ -60,6 +61,9 @@ properties:
> description: Specify the number of delay for tx sampling.
> $ref: /schemas/types.yaml#/definitions/uint8
>
> + thead,phy-pull-up:
> + description: Enable weak pull-up on PHY pads
> + type: boolean
Why is the weak pull-up required? How would the dts author know if they
need to use this property?
Thanks,
Conor.
>
> required:
> - compatible
>
> --
> 2.34.1
>
On Fri, Sep 22, 2023 at 10:57:36AM +0100, Conor Dooley wrote:
> Hey Drew,
>
> On Thu, Sep 21, 2023 at 06:49:48PM -0700, Drew Fustini wrote:
> > Add compatible value for the T-Head TH1520 dwcmshc controller and add
> > thead,phy-pull-up property.
> >
> > Signed-off-by: Drew Fustini <[email protected]>
> > ---
> > Documentation/devicetree/bindings/mmc/snps,dwcmshc-sdhci.yaml | 4 ++++
> > 1 file changed, 4 insertions(+)
> >
> > diff --git a/Documentation/devicetree/bindings/mmc/snps,dwcmshc-sdhci.yaml b/Documentation/devicetree/bindings/mmc/snps,dwcmshc-sdhci.yaml
> > index a43eb837f8da..46b768d46712 100644
> > --- a/Documentation/devicetree/bindings/mmc/snps,dwcmshc-sdhci.yaml
> > +++ b/Documentation/devicetree/bindings/mmc/snps,dwcmshc-sdhci.yaml
> > @@ -19,6 +19,7 @@ properties:
> > - rockchip,rk3568-dwcmshc
> > - rockchip,rk3588-dwcmshc
> > - snps,dwcmshc-sdhci
> > + - thead,th1520-dwcmshc
> >
> > reg:
> > maxItems: 1
> > @@ -60,6 +61,9 @@ properties:
> > description: Specify the number of delay for tx sampling.
> > $ref: /schemas/types.yaml#/definitions/uint8
> >
> > + thead,phy-pull-up:
> > + description: Enable weak pull-up on PHY pads
> > + type: boolean
>
> Why is the weak pull-up required? How would the dts author know if they
> need to use this property?
This is a good question, and I don't have a good reason beyond it is
what the vendor SDK was doing.
There are only two boards right now using the TH1520 that I know of.
Both the LPi4a [1] and the Ahead [2] have the pull-up property set on
all the mmc controller nodes their downstream device trees.
Rob suggested on #devicetree that it would be simpler to just enable it
in the driver and disable support when needed. I like this idea as it
will simplify this binding patch and the code in the driver patch.
Thanks,
Drew
[1] https://git.beagleboard.org/beaglev-ahead/BeagleBoard-DeviceTrees/-/blob/v5.10.x-ti-unified/src/riscv/light-beagle-ref.dts
[2] https://github.com/revyos/thead-kernel/blob/lpi4a/arch/riscv/boot/dts/thead/light-lpi4a-ref.dts
On Fri, Sep 22, 2023 at 11:18 PM Drew Fustini <[email protected]> wrote:
>
> On Fri, Sep 22, 2023 at 10:57:36AM +0100, Conor Dooley wrote:
> > Hey Drew,
> >
> > On Thu, Sep 21, 2023 at 06:49:48PM -0700, Drew Fustini wrote:
> > > Add compatible value for the T-Head TH1520 dwcmshc controller and add
> > > thead,phy-pull-up property.
> > >
> > > Signed-off-by: Drew Fustini <[email protected]>
> > > ---
> > > Documentation/devicetree/bindings/mmc/snps,dwcmshc-sdhci.yaml | 4 ++++
> > > 1 file changed, 4 insertions(+)
> > >
> > > diff --git a/Documentation/devicetree/bindings/mmc/snps,dwcmshc-sdhci.yaml b/Documentation/devicetree/bindings/mmc/snps,dwcmshc-sdhci.yaml
> > > index a43eb837f8da..46b768d46712 100644
> > > --- a/Documentation/devicetree/bindings/mmc/snps,dwcmshc-sdhci.yaml
> > > +++ b/Documentation/devicetree/bindings/mmc/snps,dwcmshc-sdhci.yaml
> > > @@ -19,6 +19,7 @@ properties:
> > > - rockchip,rk3568-dwcmshc
> > > - rockchip,rk3588-dwcmshc
> > > - snps,dwcmshc-sdhci
> > > + - thead,th1520-dwcmshc
> > >
> > > reg:
> > > maxItems: 1
> > > @@ -60,6 +61,9 @@ properties:
> > > description: Specify the number of delay for tx sampling.
> > > $ref: /schemas/types.yaml#/definitions/uint8
> > >
> > > + thead,phy-pull-up:
> > > + description: Enable weak pull-up on PHY pads
> > > + type: boolean
> >
> > Why is the weak pull-up required? How would the dts author know if they
> > need to use this property?
>
> This is a good question, and I don't have a good reason beyond it is
> what the vendor SDK was doing.
>
> There are only two boards right now using the TH1520 that I know of.
> Both the LPi4a [1] and the Ahead [2] have the pull-up property set on
> all the mmc controller nodes their downstream device trees.
>
> Rob suggested on #devicetree that it would be simpler to just enable it
> in the driver and disable support when needed. I like this idea as it
> will simplify this binding patch and the code in the driver patch.
It's for the PHY debug. You could directly remove them, or keep it
with no-pull-up flag, then no pull-up flag in the dts for default..
static void sdhci_phy_1_8v_init_no_pull(struct sdhci_host *host)
{
uint32_t val;
sdhci_writel(host, 1, DWC_MSHC_PTR_PHY_R);
sdhci_writeb(host, 1 << 4, PHY_SDCLKDL_CNFG_R);
sdhci_writeb(host, 0x40, PHY_SDCLKDL_DC_R);
val = sdhci_readb(host, PHY_SDCLKDL_CNFG_R);
val &= ~(1 << 4);
sdhci_writeb(host, val, PHY_SDCLKDL_CNFG_R);
val = sdhci_readw(host, PHY_CMDPAD_CNFG_R);
sdhci_writew(host, val | 1, PHY_CMDPAD_CNFG_R);
val = sdhci_readw(host, PHY_DATAPAD_CNFG_R);
sdhci_writew(host, val | 1, PHY_DATAPAD_CNFG_R);
val = sdhci_readw(host, PHY_RSTNPAD_CNFG_R);
sdhci_writew(host, val | 1, PHY_RSTNPAD_CNFG_R);
val = sdhci_readw(host, PHY_STBPAD_CNFG_R);
sdhci_writew(host, val | 1, PHY_STBPAD_CNFG_R);
val = sdhci_readb(host, PHY_DLL_CTRL_R);
sdhci_writeb(host, val | 1, PHY_DLL_CTRL_R);
}
static void sdhci_phy_3_3v_init_no_pull(struct sdhci_host *host)
{
uint32_t val;
sdhci_writel(host, 1, DWC_MSHC_PTR_PHY_R);
sdhci_writeb(host, 1 << 4, PHY_SDCLKDL_CNFG_R);
sdhci_writeb(host, 0x40, PHY_SDCLKDL_DC_R);
val = sdhci_readb(host, PHY_SDCLKDL_CNFG_R);
val &= ~(1 << 4);
sdhci_writeb(host, val, PHY_SDCLKDL_CNFG_R);
val = sdhci_readw(host, PHY_CMDPAD_CNFG_R);
sdhci_writew(host, val | 2, PHY_CMDPAD_CNFG_R);
val = sdhci_readw(host, PHY_DATAPAD_CNFG_R);
sdhci_writew(host, val | 2, PHY_DATAPAD_CNFG_R);
val = sdhci_readw(host, PHY_RSTNPAD_CNFG_R);
sdhci_writew(host, val | 2, PHY_RSTNPAD_CNFG_R);
val = sdhci_readw(host, PHY_STBPAD_CNFG_R);
sdhci_writew(host, val | 2, PHY_STBPAD_CNFG_R);
val = sdhci_readb(host, PHY_DLL_CTRL_R);
sdhci_writeb(host, val | 1, PHY_DLL_CTRL_R);
}
>
> Thanks,
> Drew
>
> [1] https://git.beagleboard.org/beaglev-ahead/BeagleBoard-DeviceTrees/-/blob/v5.10.x-ti-unified/src/riscv/light-beagle-ref.dts
> [2] https://github.com/revyos/thead-kernel/blob/lpi4a/arch/riscv/boot/dts/thead/light-lpi4a-ref.dts
--
Best Regards
Guo Ren
On Sat, Sep 23, 2023 at 04:10:11PM +0800, Guo Ren wrote:
> On Fri, Sep 22, 2023 at 11:18 PM Drew Fustini <[email protected]> wrote:
> >
> > On Fri, Sep 22, 2023 at 10:57:36AM +0100, Conor Dooley wrote:
> > > Hey Drew,
> > >
> > > On Thu, Sep 21, 2023 at 06:49:48PM -0700, Drew Fustini wrote:
> > > > Add compatible value for the T-Head TH1520 dwcmshc controller and add
> > > > thead,phy-pull-up property.
> > > >
> > > > Signed-off-by: Drew Fustini <[email protected]>
> > > > ---
> > > > Documentation/devicetree/bindings/mmc/snps,dwcmshc-sdhci.yaml | 4 ++++
> > > > 1 file changed, 4 insertions(+)
> > > >
> > > > diff --git a/Documentation/devicetree/bindings/mmc/snps,dwcmshc-sdhci.yaml b/Documentation/devicetree/bindings/mmc/snps,dwcmshc-sdhci.yaml
> > > > index a43eb837f8da..46b768d46712 100644
> > > > --- a/Documentation/devicetree/bindings/mmc/snps,dwcmshc-sdhci.yaml
> > > > +++ b/Documentation/devicetree/bindings/mmc/snps,dwcmshc-sdhci.yaml
> > > > @@ -19,6 +19,7 @@ properties:
> > > > - rockchip,rk3568-dwcmshc
> > > > - rockchip,rk3588-dwcmshc
> > > > - snps,dwcmshc-sdhci
> > > > + - thead,th1520-dwcmshc
> > > >
> > > > reg:
> > > > maxItems: 1
> > > > @@ -60,6 +61,9 @@ properties:
> > > > description: Specify the number of delay for tx sampling.
> > > > $ref: /schemas/types.yaml#/definitions/uint8
> > > >
> > > > + thead,phy-pull-up:
> > > > + description: Enable weak pull-up on PHY pads
> > > > + type: boolean
> > >
> > > Why is the weak pull-up required? How would the dts author know if they
> > > need to use this property?
> >
> > This is a good question, and I don't have a good reason beyond it is
> > what the vendor SDK was doing.
> >
> > There are only two boards right now using the TH1520 that I know of.
> > Both the LPi4a [1] and the Ahead [2] have the pull-up property set on
> > all the mmc controller nodes their downstream device trees.
> >
> > Rob suggested on #devicetree that it would be simpler to just enable it
> > in the driver and disable support when needed. I like this idea as it
> > will simplify this binding patch and the code in the driver patch.
> It's for the PHY debug. You could directly remove them, or keep it
> with no-pull-up flag, then no pull-up flag in the dts for default..
Thank you for explaining that the purpose of the pull-up DT property
was for PHY debug.
I will plan to remove the pull-up DT property in the next version of
this patch series and remove sdhci_phy_1_8v_init_no_pull() and
sdhci_phy_3_3v_init_no_pull() from my sdhci-of-dwcmshc.c patch.
I will make th1520_phy_1_8v_init() and th1520_phy_3_3v_init() always
set WEAKPULL_EN = 1 (PULLUP) for CMDPAD_CNFG, DATAPAD_CNFG, RSTNPAD_CNFG
and set WEAKPULL_EN = 2 (PULLDOWN) for STBPAD_CNFG.
Thanks,
Drew