diff mbox series

[net-next,2/3] net: bcmgenet: Pass "main" clock down to the MDIO driver

Message ID 20240216184237.259954-3-florian.fainelli@broadcom.com
State New
Headers
Series Rework GENET MDIO controller clocking |

Commit Message

Florian Fainelli Feb. 16, 2024, 6:42 p.m. UTC 
  GENET has historically had to create a MDIO platform device for its
controller and pass some auxiliary data to it, like a MDIO completion
callback. Now we also pass the "main" clock to allow for the MDIO bus
controller to manage that clock adequately around I/O accesses.

Signed-off-by: Florian Fainelli <florian.fainelli@broadcom.com>
---
 drivers/net/ethernet/broadcom/genet/bcmmii.c | 4 ++++
 1 file changed, 4 insertions(+)

Comments

Florian Fainelli Feb. 16, 2024, 10:50 p.m. UTC | #1 
On 2/16/24 14:41, Jacob Keller wrote:
> 
> 
> On 2/16/2024 10:42 AM, Florian Fainelli wrote:
>> GENET has historically had to create a MDIO platform device for its
>> controller and pass some auxiliary data to it, like a MDIO completion
>> callback. Now we also pass the "main" clock to allow for the MDIO bus
>> controller to manage that clock adequately around I/O accesses.
>>
>> Signed-off-by: Florian Fainelli <florian.fainelli@broadcom.com>
>> ---
>>   drivers/net/ethernet/broadcom/genet/bcmmii.c | 4 ++++
>>   1 file changed, 4 insertions(+)
>>
>> diff --git a/drivers/net/ethernet/broadcom/genet/bcmmii.c b/drivers/net/ethernet/broadcom/genet/bcmmii.c
>> index cbbe004621bc..7a21950da77c 100644
>> --- a/drivers/net/ethernet/broadcom/genet/bcmmii.c
>> +++ b/drivers/net/ethernet/broadcom/genet/bcmmii.c
>> @@ -476,6 +476,10 @@ static int bcmgenet_mii_register(struct bcmgenet_priv *priv)
>>   	ppd.wait_func = bcmgenet_mii_wait;
>>   	ppd.wait_func_data = priv;
>>   	ppd.bus_name = "bcmgenet MII bus";
>> +	/* Pass a reference to our "main" clock which is used for MDIO
>> +	 * transfers
>> +	 */
>> +	ppd.clk = priv->clk;
>>   
>>   	/* Unimac MDIO bus controller starts at UniMAC offset + MDIO_CMD
>>   	 * and is 2 * 32-bits word long, 8 bytes total.
> 
> Is this missing a modification of the header file to add the clk field
> to struct unimac_mdio_pdata? I don't see that field in the
> include/linux/platform_data/mdio-bcm-unimac.h header currently...
> 
> Oh. you included that in the first patch of the series. I see.

I suppose I could have included it in patch #1, and have introduced in 
patch #2 the hunk that dealt with fetching pdata->clk, but since I was 
re-organizing the mdio-bcm-unimac.c driver's probe function, it felt 
more natural to arrange it that way.

> 
> It feels like the series would be more natural of this was 1/3 instead
> of 2/3, since the current 1/3 patch depends on this clk value being set, no?

I sort of debated that with myself, and ended up going with: put the 
plumbing first, wire it later, rather than the opposite. If someone was 
to run a bisection there would not be any difference in behavior until 
patch #2 regardless of their ordering.

> 
> The result of the series makes sense tho:
> 
> Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>

Thanks Jacob!
Andrew Lunn Feb. 17, 2024, 3:21 p.m. UTC | #2 
On Fri, Feb 16, 2024 at 10:42:36AM -0800, Florian Fainelli wrote:
> GENET has historically had to create a MDIO platform device for its
> controller and pass some auxiliary data to it, like a MDIO completion
> callback. Now we also pass the "main" clock to allow for the MDIO bus
> controller to manage that clock adequately around I/O accesses.

I guess this code comes from before the times of DT? I would normally
expect to see a clock added to the DT node for the MDIO bus. But if
there is no node, because it is not in DT....

      Andrew
Florian Fainelli Feb. 17, 2024, 5:18 p.m. UTC | #3 
Hi Andrew,

On 2/17/2024 7:21 AM, Andrew Lunn wrote:
> On Fri, Feb 16, 2024 at 10:42:36AM -0800, Florian Fainelli wrote:
>> GENET has historically had to create a MDIO platform device for its
>> controller and pass some auxiliary data to it, like a MDIO completion
>> callback. Now we also pass the "main" clock to allow for the MDIO bus
>> controller to manage that clock adequately around I/O accesses.
> 
> I guess this code comes from before the times of DT? I would normally
> expect to see a clock added to the DT node for the MDIO bus. But if
> there is no node, because it is not in DT....

The driver started being DT-only from the get go, however it was also my 
group's first attempt at upstreaming a driver and we did not get 
everything right in terms of the DT binding. In particular there was no 
"mdio" sub-node initially, but we still wanted to be able to split up 
the MDIO controller part since we knew it was going to be re-used in 
other designs (bcm_sf2 and later asp2). The platform device was the best 
we could come up with at the time.

All of our DTBs deployed out there do not have a "clocks" property 
within the "mdio" sub-mode of the GENET Ethernet node, so that is why we 
are doing this.

Thanks!
diff mbox series

Patch

diff --git a/drivers/net/ethernet/broadcom/genet/bcmmii.c b/drivers/net/ethernet/broadcom/genet/bcmmii.c
index cbbe004621bc..7a21950da77c 100644
--- a/drivers/net/ethernet/broadcom/genet/bcmmii.c
+++ b/drivers/net/ethernet/broadcom/genet/bcmmii.c
@@ -476,6 +476,10 @@  static int bcmgenet_mii_register(struct bcmgenet_priv *priv)
 	ppd.wait_func = bcmgenet_mii_wait;
 	ppd.wait_func_data = priv;
 	ppd.bus_name = "bcmgenet MII bus";
+	/* Pass a reference to our "main" clock which is used for MDIO
+	 * transfers
+	 */
+	ppd.clk = priv->clk;
 
 	/* Unimac MDIO bus controller starts at UniMAC offset + MDIO_CMD
 	 * and is 2 * 32-bits word long, 8 bytes total.