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SubjectRe: [PATCH 01/10] net: stmmac: Enable stmmac main clock when probing hardware
Hello Chen-Yu

On 12/6/2013 6:29 PM, Chen-Yu Tsai wrote:
> Signed-off-by: Chen-Yu Tsai <wens@csie.org>
> ---
>
> Guiseppe previously stated that the "stmmaceth" clock is the
> main clock that drives the IP. The stmmac driver does not
> enable this clock during the probe phase. When the driver is
> built in to the kernel, this is fine because the clock maybe
> on by default, or the boot loader had enabled it.
>
> If stmmac is built as a module, when the module is loaded,
> the clock may be found unused and disabled by the kernel.

the clk_prepare_enable is then called in the open.
Is it not working for you?
Do you mean that the stmmac_hw_init fails if you do not move
the clk_get and clk_prepare_enable on top of the stmmac_dvr_probe?

Peppe

>
> drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 24 +++++++++++++----------
> 1 file changed, 14 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> index 8d4ccd3..7da71ed 100644
> --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> @@ -2688,10 +2688,17 @@ struct stmmac_priv *stmmac_dvr_probe(struct device *device,
> if ((phyaddr >= 0) && (phyaddr <= 31))
> priv->plat->phy_addr = phyaddr;
>
> + priv->stmmac_clk = clk_get(priv->device, STMMAC_RESOURCE_NAME);
> + if (IS_ERR(priv->stmmac_clk)) {
> + pr_warn("%s: warning: cannot get CSR clock\n", __func__);
> + goto error_clk_get;
> + }
> + clk_prepare_enable(priv->stmmac_clk);
> +
> /* Init MAC and get the capabilities */
> ret = stmmac_hw_init(priv);
> if (ret)
> - goto error_free_netdev;
> + goto error_hw_init;
>
> ndev->netdev_ops = &stmmac_netdev_ops;
>
> @@ -2729,12 +2736,6 @@ struct stmmac_priv *stmmac_dvr_probe(struct device *device,
> goto error_netdev_register;
> }
>
> - priv->stmmac_clk = clk_get(priv->device, STMMAC_RESOURCE_NAME);
> - if (IS_ERR(priv->stmmac_clk)) {
> - pr_warn("%s: warning: cannot get CSR clock\n", __func__);
> - goto error_clk_get;
> - }
> -
> /* If a specific clk_csr value is passed from the platform
> * this means that the CSR Clock Range selection cannot be
> * changed at run-time and it is fixed. Viceversa the driver'll try to
> @@ -2759,15 +2760,18 @@ struct stmmac_priv *stmmac_dvr_probe(struct device *device,
> }
> }
>
> + clk_disable_unprepare(priv->stmmac_clk);
> +
> return priv;
>
> error_mdio_register:
> - clk_put(priv->stmmac_clk);
> -error_clk_get:
> unregister_netdev(ndev);
> error_netdev_register:
> netif_napi_del(&priv->napi);
> -error_free_netdev:
> +error_hw_init:
> + clk_disable_unprepare(priv->stmmac_clk);
> + clk_put(priv->stmmac_clk);
> +error_clk_get:
> free_netdev(ndev);
>
> return NULL;
>



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