Re: [RFC] ravb: Add support for optional txc_refclk

2020-12-28 Thread Geert Uytterhoeven 
Hi Adam,

CC devicetree

On Mon, Dec 28, 2020 at 2:49 PM Adam Ford  wrote:
> On Mon, Dec 14, 2020 at 4:05 AM Geert Uytterhoeven  
> wrote:
> > On Sun, Dec 13, 2020 at 5:18 PM Adam Ford  wrote:
> > > The SoC expects the txv_refclk is provided, but if it is provided
> > > by a programmable clock, there needs to be a way to get and enable
> > > this clock to operate.  It needs to be optional since it's only
> > > necessary for those with programmable clocks.
> > >
> > > Signed-off-by: Adam Ford 
> >
> > Thanks for your patch!
> >
> > > --- a/drivers/net/ethernet/renesas/ravb.h
> > > +++ b/drivers/net/ethernet/renesas/ravb.h
> > > @@ -994,6 +994,7 @@ struct ravb_private {
> > > struct platform_device *pdev;
> > > void __iomem *addr;
> > > struct clk *clk;
> > > +   struct clk *ref_clk;
> > > struct mdiobb_ctrl mdiobb;
> > > u32 num_rx_ring[NUM_RX_QUEUE];
> > > u32 num_tx_ring[NUM_TX_QUEUE];
> > > diff --git a/drivers/net/ethernet/renesas/ravb_main.c 
> > > b/drivers/net/ethernet/renesas/ravb_main.c
> > > index bd30505fbc57..4c3f95923ef2 100644
> > > --- a/drivers/net/ethernet/renesas/ravb_main.c
> > > +++ b/drivers/net/ethernet/renesas/ravb_main.c
> > > @@ -2148,6 +2148,18 @@ static int ravb_probe(struct platform_device *pdev)
> > > goto out_release;
> > > }
> > >
> > > +   priv->ref_clk = devm_clk_get(>dev, "txc_refclk");
> >
> > Please also update the DT bindings[1], to document the optional
> > presence of the clock.
>
> I am not all that familiar with the YAML syntax, but right now, the
> clock-names property isn't in the binding, and the driver doesn't use
> a name when requesting the single clock it's expecting.
> Since the txc_refclk is optional, can the clock-names property allow
> for 0-2 names while the number of clocks be 1-2?
>
> clocks:
> minItems: 1
> maxItems: 2
>
>   clock-names:
> minItems: 0
> maxItems: 2
> items:
>   enum:
> - fck # AVB functional clock (optional if it is the only clock)
> - txc_refclk # TXC reference clock

With "enum", it accepts any order. But for compatibility, we want to force
"fck" first.

Something like:

  clocks:
minItems: 1
items:
  - description: AVB functional clock
  - description: Optional TXC reference clock

  clock-names:
items:
  - const: fck
  - const: txc_refclk

> With the above proposal, the clock-names would only be necessary when
> using the txc_refclk.

I think that's difficult to express: either make clock-names optional (i.e.
don't list it under "required"), or make it required in all cases (which need
fixups for the existing users, and "minItems: 1" for "clock-names", too).

> > > +   if (IS_ERR(priv->ref_clk)) {
> > > +   if (PTR_ERR(priv->ref_clk) == -EPROBE_DEFER) {
> > > +   /* for Probe defer return error */
> > > +   error = PTR_ERR(priv->ref_clk);
> > > +   goto out_release;
> > > +   }
> > > +   /* Ignore other errors since it's optional */
> > > +   } else {
> > > +   (void)clk_prepare_enable(priv->ref_clk);
> >
> > This can fail.
> > Does this clock need to be enabled all the time?
> > At least it should be disabled in the probe failure path, and in
> > ravb_remove().
>
> I'll do that for the next rev.
>
> thanks,
>
> adam
> >
> > [1] Documentation/devicetree/bindings/net/renesas,etheravb.yaml

Gr{oetje,eeting}s,

Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- ge...@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds

Re: [RFC] ravb: Add support for optional txc_refclk

2020-12-28 Thread Adam Ford 
On Mon, Dec 14, 2020 at 4:05 AM Geert Uytterhoeven  wrote:
>
> Hi Adam,
>
> On Sun, Dec 13, 2020 at 5:18 PM Adam Ford  wrote:
> > The SoC expects the txv_refclk is provided, but if it is provided
> > by a programmable clock, there needs to be a way to get and enable
> > this clock to operate.  It needs to be optional since it's only
> > necessary for those with programmable clocks.
> >
> > Signed-off-by: Adam Ford 
>
> Thanks for your patch!
>
> > --- a/drivers/net/ethernet/renesas/ravb.h
> > +++ b/drivers/net/ethernet/renesas/ravb.h
> > @@ -994,6 +994,7 @@ struct ravb_private {
> > struct platform_device *pdev;
> > void __iomem *addr;
> > struct clk *clk;
> > +   struct clk *ref_clk;
> > struct mdiobb_ctrl mdiobb;
> > u32 num_rx_ring[NUM_RX_QUEUE];
> > u32 num_tx_ring[NUM_TX_QUEUE];
> > diff --git a/drivers/net/ethernet/renesas/ravb_main.c 
> > b/drivers/net/ethernet/renesas/ravb_main.c
> > index bd30505fbc57..4c3f95923ef2 100644
> > --- a/drivers/net/ethernet/renesas/ravb_main.c
> > +++ b/drivers/net/ethernet/renesas/ravb_main.c
> > @@ -2148,6 +2148,18 @@ static int ravb_probe(struct platform_device *pdev)
> > goto out_release;
> > }
> >
> > +   priv->ref_clk = devm_clk_get(>dev, "txc_refclk");
>
> Please also update the DT bindings[1], to document the optional
> presence of the clock.

I am not all that familiar with the YAML syntax, but right now, the
clock-names property isn't in the binding, and the driver doesn't use
a name when requesting the single clock it's expecting.
Since the txc_refclk is optional, can the clock-names property allow
for 0-2 names while the number of clocks be 1-2?

clocks:
minItems: 1
maxItems: 2

  clock-names:
minItems: 0
maxItems: 2
items:
  enum:
- fck # AVB functional clock (optional if it is the only clock)
- txc_refclk # TXC reference clock

With the above proposal, the clock-names would only be necessary when
using the txc_refclk.

>
> > +   if (IS_ERR(priv->ref_clk)) {
> > +   if (PTR_ERR(priv->ref_clk) == -EPROBE_DEFER) {
> > +   /* for Probe defer return error */
> > +   error = PTR_ERR(priv->ref_clk);
> > +   goto out_release;
> > +   }
> > +   /* Ignore other errors since it's optional */
> > +   } else {
> > +   (void)clk_prepare_enable(priv->ref_clk);
>
> This can fail.
> Does this clock need to be enabled all the time?
> At least it should be disabled in the probe failure path, and in
> ravb_remove().

I'll do that for the next rev.

thanks,

adam
>
> [1] Documentation/devicetree/bindings/net/renesas,etheravb.yaml
>
> Gr{oetje,eeting}s,
>
> Geert
>
> --
> Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- 
> ge...@linux-m68k.org
>
> In personal conversations with technical people, I call myself a hacker. But
> when I'm talking to journalists I just say "programmer" or something like 
> that.
> -- Linus Torvalds

Re: [RFC] ravb: Add support for optional txc_refclk

2020-12-14 Thread Geert Uytterhoeven 
Hi Adam,

On Sun, Dec 13, 2020 at 5:18 PM Adam Ford  wrote:
> The SoC expects the txv_refclk is provided, but if it is provided
> by a programmable clock, there needs to be a way to get and enable
> this clock to operate.  It needs to be optional since it's only
> necessary for those with programmable clocks.
>
> Signed-off-by: Adam Ford 

Thanks for your patch!

> --- a/drivers/net/ethernet/renesas/ravb.h
> +++ b/drivers/net/ethernet/renesas/ravb.h
> @@ -994,6 +994,7 @@ struct ravb_private {
> struct platform_device *pdev;
> void __iomem *addr;
> struct clk *clk;
> +   struct clk *ref_clk;
> struct mdiobb_ctrl mdiobb;
> u32 num_rx_ring[NUM_RX_QUEUE];
> u32 num_tx_ring[NUM_TX_QUEUE];
> diff --git a/drivers/net/ethernet/renesas/ravb_main.c 
> b/drivers/net/ethernet/renesas/ravb_main.c
> index bd30505fbc57..4c3f95923ef2 100644
> --- a/drivers/net/ethernet/renesas/ravb_main.c
> +++ b/drivers/net/ethernet/renesas/ravb_main.c
> @@ -2148,6 +2148,18 @@ static int ravb_probe(struct platform_device *pdev)
> goto out_release;
> }
>
> +   priv->ref_clk = devm_clk_get(>dev, "txc_refclk");

Please also update the DT bindings[1], to document the optional
presence of the clock.

> +   if (IS_ERR(priv->ref_clk)) {
> +   if (PTR_ERR(priv->ref_clk) == -EPROBE_DEFER) {
> +   /* for Probe defer return error */
> +   error = PTR_ERR(priv->ref_clk);
> +   goto out_release;
> +   }
> +   /* Ignore other errors since it's optional */
> +   } else {
> +   (void)clk_prepare_enable(priv->ref_clk);

This can fail.
Does this clock need to be enabled all the time?
At least it should be disabled in the probe failure path, and in
ravb_remove().

[1] Documentation/devicetree/bindings/net/renesas,etheravb.yaml

Gr{oetje,eeting}s,

Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- ge...@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds

Re: [RFC] ravb: Add support for optional txc_refclk

2020-12-12 Thread Adam Ford 
On Sat, Dec 12, 2020 at 11:55 AM Sergei Shtylyov
 wrote:
>
> Hello!
>
> On 12.12.2020 19:56, Adam Ford wrote:
>
> > The SoC expects the txv_refclk is provided, but if it is provided
> > by a programmable clock, there needs to be a way to get and enable
> > this clock to operate.  It needs to be optional since it's only
> > necessary for those with programmable clocks.
> >
> > Signed-off-by: Adam Ford 
> [...]
> > diff --git a/drivers/net/ethernet/renesas/ravb_main.c 
> > b/drivers/net/ethernet/renesas/ravb_main.c
> > index bd30505fbc57..4c3f95923ef2 100644
> > --- a/drivers/net/ethernet/renesas/ravb_main.c
> > +++ b/drivers/net/ethernet/renesas/ravb_main.c
> > @@ -2148,6 +2148,18 @@ static int ravb_probe(struct platform_device *pdev)
> >   goto out_release;
> >   }
> >
> > + priv->ref_clk = devm_clk_get(>dev, "txc_refclk");
>
> Why not devm_clk_get_optional()?

I am not that familiar with the clock API.  I'll look into that
function. It looks like it makes more sense.  I'll send a V2.

adam
>
> > + if (IS_ERR(priv->ref_clk)) {
> > + if (PTR_ERR(priv->ref_clk) == -EPROBE_DEFER) {
> > + /* for Probe defer return error */
> > + error = PTR_ERR(priv->ref_clk);
> > + goto out_release;
> > + }
> > + /* Ignore other errors since it's optional */
> > + } else {
> > + (void)clk_prepare_enable(priv->ref_clk);
> > + }
> > +
> >   ndev->max_mtu = 2048 - (ETH_HLEN + VLAN_HLEN + ETH_FCS_LEN);
> >   ndev->min_mtu = ETH_MIN_MTU;
> >
>
> MBR, Sergei

Re: [RFC] ravb: Add support for optional txc_refclk

2020-12-12 Thread Sergei Shtylyov 

Hello!

On 12.12.2020 19:56, Adam Ford wrote:


The SoC expects the txv_refclk is provided, but if it is provided
by a programmable clock, there needs to be a way to get and enable
this clock to operate.  It needs to be optional since it's only
necessary for those with programmable clocks.

Signed-off-by: Adam Ford 

[...]

diff --git a/drivers/net/ethernet/renesas/ravb_main.c 
b/drivers/net/ethernet/renesas/ravb_main.c
index bd30505fbc57..4c3f95923ef2 100644
--- a/drivers/net/ethernet/renesas/ravb_main.c
+++ b/drivers/net/ethernet/renesas/ravb_main.c
@@ -2148,6 +2148,18 @@ static int ravb_probe(struct platform_device *pdev)
goto out_release;
}
  
+	priv->ref_clk = devm_clk_get(>dev, "txc_refclk");


   Why not devm_clk_get_optional()?


+   if (IS_ERR(priv->ref_clk)) {
+   if (PTR_ERR(priv->ref_clk) == -EPROBE_DEFER) {
+   /* for Probe defer return error */
+   error = PTR_ERR(priv->ref_clk);
+   goto out_release;
+   }
+   /* Ignore other errors since it's optional */
+   } else {
+   (void)clk_prepare_enable(priv->ref_clk);
+   }
+
ndev->max_mtu = 2048 - (ETH_HLEN + VLAN_HLEN + ETH_FCS_LEN);
ndev->min_mtu = ETH_MIN_MTU;
  


MBR, Sergei

[RFC] ravb: Add support for optional txc_refclk

2020-12-12 Thread Adam Ford 
The SoC expects the txv_refclk is provided, but if it is provided
by a programmable clock, there needs to be a way to get and enable
this clock to operate.  It needs to be optional since it's only
necessary for those with programmable clocks.

Signed-off-by: Adam Ford 

diff --git a/drivers/net/ethernet/renesas/ravb.h 
b/drivers/net/ethernet/renesas/ravb.h
index 7453b17a37a2..ddf3bc5164d2 100644
--- a/drivers/net/ethernet/renesas/ravb.h
+++ b/drivers/net/ethernet/renesas/ravb.h
@@ -994,6 +994,7 @@ struct ravb_private {
struct platform_device *pdev;
void __iomem *addr;
struct clk *clk;
+   struct clk *ref_clk;
struct mdiobb_ctrl mdiobb;
u32 num_rx_ring[NUM_RX_QUEUE];
u32 num_tx_ring[NUM_TX_QUEUE];
diff --git a/drivers/net/ethernet/renesas/ravb_main.c 
b/drivers/net/ethernet/renesas/ravb_main.c
index bd30505fbc57..4c3f95923ef2 100644
--- a/drivers/net/ethernet/renesas/ravb_main.c
+++ b/drivers/net/ethernet/renesas/ravb_main.c
@@ -2148,6 +2148,18 @@ static int ravb_probe(struct platform_device *pdev)
goto out_release;
}
 
+   priv->ref_clk = devm_clk_get(>dev, "txc_refclk");
+   if (IS_ERR(priv->ref_clk)) {
+   if (PTR_ERR(priv->ref_clk) == -EPROBE_DEFER) {
+   /* for Probe defer return error */
+   error = PTR_ERR(priv->ref_clk);
+   goto out_release;
+   }
+   /* Ignore other errors since it's optional */
+   } else {
+   (void)clk_prepare_enable(priv->ref_clk);
+   }
+
ndev->max_mtu = 2048 - (ETH_HLEN + VLAN_HLEN + ETH_FCS_LEN);
ndev->min_mtu = ETH_MIN_MTU;
 
-- 
2.25.1