On Tue, 2017-10-10 at 15:19 +1030, Joel Stanley wrote:
> According to the ASPEED datasheet, gigabit speeds require a clock of
> 100MHz or higher. Other speeds require 25MHz or higher.
Did you try "live" changing by either using ethtool or plugging into
switches/hubs at different speed ?
Also this is aspeed'isms, we should probably keep that under an
is_aspeed test.
My assumption is that we wouldn't bother, and just leave the freq
set based on whether there's a physical gigabit capable connection or
not (ie, real gigabit PHY vs. NC-SI really). But if it can help save a
few milliwatts..
> Signed-off-by: Joel Stanley <j...@jms.id.au>
> ---
> drivers/net/ethernet/faraday/ftgmac100.c | 22 ++++++++++++++++++++++
> 1 file changed, 22 insertions(+)
>
> diff --git a/drivers/net/ethernet/faraday/ftgmac100.c
> b/drivers/net/ethernet/faraday/ftgmac100.c
> index 9ed8e4b81530..870ebd857978 100644
> --- a/drivers/net/ethernet/faraday/ftgmac100.c
> +++ b/drivers/net/ethernet/faraday/ftgmac100.c
> @@ -21,6 +21,7 @@
>
> #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
>
> +#include <linux/clk.h>
> #include <linux/dma-mapping.h>
> #include <linux/etherdevice.h>
> #include <linux/ethtool.h>
> @@ -59,6 +60,9 @@
> /* Min number of tx ring entries before stopping queue */
> #define TX_THRESHOLD (MAX_SKB_FRAGS + 1)
>
> +#define FTGMAC_100MHZ 100000000
> +#define FTGMAC_25MHZ 25000000
> +
> struct ftgmac100 {
> /* Registers */
> struct resource *res;
> @@ -96,6 +100,7 @@ struct ftgmac100 {
> struct napi_struct napi;
> struct work_struct reset_task;
> struct mii_bus *mii_bus;
> + struct clk *clk;
>
> /* Link management */
> int cur_speed;
> @@ -142,18 +147,22 @@ static int ftgmac100_reset_mac(struct ftgmac100 *priv,
> u32 maccr)
> static int ftgmac100_reset_and_config_mac(struct ftgmac100 *priv)
> {
> u32 maccr = 0;
> + int freq = 0;
>
> switch (priv->cur_speed) {
> case SPEED_10:
> case 0: /* no link */
> + freq = FTGMAC_25MHZ;
> break;
>
> case SPEED_100:
> maccr |= FTGMAC100_MACCR_FAST_MODE;
> + freq = FTGMAC_25MHZ;
> break;
>
> case SPEED_1000:
> maccr |= FTGMAC100_MACCR_GIGA_MODE;
> + freq = FTGMAC_100MHZ;
> break;
> default:
> netdev_err(priv->netdev, "Unknown speed %d !\n",
> @@ -161,6 +170,9 @@ static int ftgmac100_reset_and_config_mac(struct
> ftgmac100 *priv)
> break;
> }
>
> + if (freq && priv->clk)
> + clk_set_rate(priv->clk, freq);
> +
> /* (Re)initialize the queue pointers */
> priv->rx_pointer = 0;
> priv->tx_clean_pointer = 0;
> @@ -1775,6 +1787,13 @@ static int ftgmac100_probe(struct platform_device
> *pdev)
> priv->dev = &pdev->dev;
> INIT_WORK(&priv->reset_task, ftgmac100_reset_task);
>
> + /* Enable clock if present */
> + priv->clk = devm_clk_get(&pdev->dev, NULL);
> + if (!IS_ERR(priv->clk))
> + clk_prepare_enable(priv->clk);
> + else
> + priv->clk = NULL;
> +
> /* map io memory */
> priv->res = request_mem_region(res->start, resource_size(res),
> dev_name(&pdev->dev));
> @@ -1883,6 +1902,9 @@ static int ftgmac100_remove(struct platform_device
> *pdev)
>
> unregister_netdev(netdev);
>
> + if (priv->clk)
> + clk_disable_unprepare(priv->clk);
> +
> /* There's a small chance the reset task will have been re-queued,
> * during stop, make sure it's gone before we free the structure.
> */
