On Wednesday 23 April 2014 at 14:24:55, Heiko Stübner wrote:
> This adds ability for the arc_emac to really handle its supplying clock.
> To get the needed clock-frequency either a real clock or the previous
> clock-frequency property must be provided.
> 
> Signed-off-by: Heiko Stuebner <[email protected]>
> ---
>  Documentation/devicetree/bindings/net/arc_emac.txt | 12 +++++-
>  drivers/net/ethernet/arc/emac.h                    |  2 +
>  drivers/net/ethernet/arc/emac_main.c               | 46
> ++++++++++++++++------ 3 files changed, 47 insertions(+), 13 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/net/arc_emac.txt
> b/Documentation/devicetree/bindings/net/arc_emac.txt index 7fbb027..a1d71eb
> 100644
> --- a/Documentation/devicetree/bindings/net/arc_emac.txt
> +++ b/Documentation/devicetree/bindings/net/arc_emac.txt
> @@ -4,11 +4,15 @@ Required properties:
>  - compatible: Should be "snps,arc-emac"
>  - reg: Address and length of the register set for the device
>  - interrupts: Should contain the EMAC interrupts
> -- clock-frequency: CPU frequency. It is needed to calculate and set polling
> -period of EMAC.
>  - max-speed: see ethernet.txt file in the same directory.
>  - phy: see ethernet.txt file in the same directory.
> 
> +Clock handling:
> +The clock frequency is needed to calculate and set polling period of EMAC.
> +It must be provided by one of:
> +- clock-frequency: CPU frequency.
> +- clocks: reference to the clock supplying the EMAC.
> +
>  Child nodes of the driver are the individual PHY devices connected to the
>  MDIO bus. They must have a "reg" property given the PHY address on the MDIO
> bus.
> 
> @@ -19,7 +23,11 @@ Examples:
>               reg = <0xc0fc2000 0x3c>;
>               interrupts = <6>;
>               mac-address = [ 00 11 22 33 44 55 ];
> +
>               clock-frequency = <80000000>;
> +             /* or */
> +             clocks = <&emac_clock>;
> +
>               max-speed = <100>;
>               phy = <&phy0>;
> 
> diff --git a/drivers/net/ethernet/arc/emac.h
> b/drivers/net/ethernet/arc/emac.h index 928fac6..53f85bf 100644
> --- a/drivers/net/ethernet/arc/emac.h
> +++ b/drivers/net/ethernet/arc/emac.h
> @@ -11,6 +11,7 @@
>  #include <linux/dma-mapping.h>
>  #include <linux/netdevice.h>
>  #include <linux/phy.h>
> +#include <linux/clk.h>
> 
>  /* STATUS and ENABLE Register bit masks */
>  #define TXINT_MASK   (1<<0)  /* Transmit interrupt */
> @@ -131,6 +132,7 @@ struct arc_emac_priv {
>       struct mii_bus *bus;
> 
>       void __iomem *regs;
> +     struct clk *clk;
> 
>       struct napi_struct napi;
>       struct net_device_stats stats;
> diff --git a/drivers/net/ethernet/arc/emac_main.c
> b/drivers/net/ethernet/arc/emac_main.c index 0cba97a..68f8ad5 100644
> --- a/drivers/net/ethernet/arc/emac_main.c
> +++ b/drivers/net/ethernet/arc/emac_main.c
> @@ -649,13 +649,6 @@ static int arc_emac_probe(struct platform_device *pdev)
> return -ENODEV;
>       }
> 
> -     /* Get CPU clock frequency from device tree */
> -     if (of_property_read_u32(pdev->dev.of_node, "clock-frequency",
> -                              &clock_frequency)) {
> -             dev_err(&pdev->dev, "failed to retrieve <clock-frequency> from 
> device
> tree\n"); -           return -EINVAL;
> -     }
> -
>       /* Get IRQ from device tree */
>       irq = irq_of_parse_and_map(pdev->dev.of_node, 0);
>       if (!irq) {
> @@ -687,13 +680,32 @@ static int arc_emac_probe(struct platform_device
> *pdev) }
>       dev_dbg(&pdev->dev, "Registers base address is 0x%p\n", priv->regs);
> 
> +     priv->clk = of_clk_get(pdev->dev.of_node, 0);
> +     if (IS_ERR(priv->clk)) {
> +             /* Get CPU clock frequency from device tree */
> +             if (of_property_read_u32(pdev->dev.of_node, "clock-frequency",
> +                                     &clock_frequency)) {
> +                     dev_err(&pdev->dev, "failed to retrieve 
> <clock-frequency> from device
> tree\n"); +                   err = -EINVAL;
> +                     goto out_netdev;
> +             }
> +     } else {
> +             err = clk_prepare_enable(priv->clk);
> +             if (err) {
> +                     dev_err(&pdev->dev, "failed to enable clock\n");
> +                     goto out_clkget;
> +             }
> +
> +             clock_frequency = clk_get_rate(priv->clk);
> +     }
> +
>       id = arc_reg_get(priv, R_ID);
> 
>       /* Check for EMAC revision 5 or 7, magic number */
>       if (!(id == 0x0005fd02 || id == 0x0007fd02)) {
>               dev_err(&pdev->dev, "ARC EMAC not detected, id=0x%x\n", id);
>               err = -ENODEV;
> -             goto out_netdev;
> +             goto out_clken;
>       }
>       dev_info(&pdev->dev, "ARC EMAC detected with id: 0x%x\n", id);
> 
> @@ -708,7 +720,7 @@ static int arc_emac_probe(struct platform_device *pdev)
>                              ndev->name, ndev);
>       if (err) {
>               dev_err(&pdev->dev, "could not allocate IRQ\n");
> -             goto out_netdev;
> +             goto out_clken;
>       }
> 
>       /* Get MAC address from device tree */
> @@ -729,7 +741,7 @@ static int arc_emac_probe(struct platform_device *pdev)
>       if (!priv->rxbd) {
>               dev_err(&pdev->dev, "failed to allocate data buffers\n");
>               err = -ENOMEM;
> -             goto out_netdev;
> +             goto out_clken;
>       }
> 
>       priv->txbd = priv->rxbd + RX_BD_NUM;
> @@ -741,7 +753,7 @@ static int arc_emac_probe(struct platform_device *pdev)
>       err = arc_mdio_probe(pdev, priv);
>       if (err) {
>               dev_err(&pdev->dev, "failed to probe MII bus\n");
> -             goto out_netdev;
> +             goto out_clken;
>       }
> 
>       priv->phy_dev = of_phy_connect(ndev, phy_node, arc_emac_adjust_link, 0,
> @@ -772,6 +784,12 @@ out_netif_api:
>       priv->phy_dev = NULL;
>  out_mdio:
>       arc_mdio_remove(priv);
> +out_clken:
> +     if (IS_ERR(priv->clk))
> +             clk_disable_unprepare(priv->clk);

Should be if (!IS_ERR(priv->clk)).

> +out_clkget:
> +     if (IS_ERR(priv->clk))
> +             clk_put(priv->clk);

The same.

>  out_netdev:
>       free_netdev(ndev);
>       return err;
> @@ -787,6 +805,12 @@ static int arc_emac_remove(struct platform_device
> *pdev) arc_mdio_remove(priv);
>       unregister_netdev(ndev);
>       netif_napi_del(&priv->napi);
> +
> +     if (!IS_ERR(priv->clk)) {
> +             clk_disable_unprepare(priv->clk);
> +             clk_put(priv->clk);
> +     }
> +
>       free_netdev(ndev);
> 
>       return 0;

Apart from that, the clock stuff has been

Tested-by: Max Schwarz <[email protected]>
(on the same hardware, radxa rock)

Cheers,
  Max
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