[PATCH] net: ftgmac100: Request clock and set speed

[Joel Stanley]

According to the ASPEED datasheet, gigabit speeds require a clock of
100MHz or higher. Other speeds require 25MHz or higher.

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.
         */
-- 
2.14.1