net: ftgmac100: Request clock and set speed

According to the ASPEED datasheet, gigabit speeds require a clock of
100MHz or higher. Other speeds require 25MHz or higher. This patch
configures a 100MHz clock if the system has a direct-attached
PHY, or 25MHz if the system is running NC-SI which is limited to 100MHz.

There appear to be no other upstream users of the FTGMAC100 driver it is
hard to know the clocking requirements of other platforms. Therefore a
conservative approach was taken with enabling clocks. If the platform is
not ASPEED, both requesting the clock and configuring the speed is
skipped.

Signed-off-by: Joel Stanley <joel@jms.id.au>
Tested-by: Andrew Jeffery <andrew@aj.id.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/faraday/ftgmac100.c b/drivers/net/ethernet/faraday/ftgmac100.c
index 9ed8e4b815304f1e443ccb7e4c863e800584b8ab..78db8e62a83f17c05d615cb674703efa4e926bd0 100644 (file)
--- 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;
@@ -1734,6 +1739,22 @@ static void ftgmac100_ncsi_handler(struct ncsi_dev *nd)
                    nd->link_up ? "up" : "down");
 }
 
+static void ftgmac100_setup_clk(struct ftgmac100 *priv)
+{
+       priv->clk = devm_clk_get(priv->dev, NULL);
+       if (IS_ERR(priv->clk))
+               return;
+
+       clk_prepare_enable(priv->clk);
+
+       /* Aspeed specifies a 100MHz clock is required for up to
+        * 1000Mbit link speeds. As NCSI is limited to 100Mbit, 25MHz
+        * is sufficient
+        */
+       clk_set_rate(priv->clk, priv->use_ncsi ? FTGMAC_25MHZ :
+                       FTGMAC_100MHZ);
+}
+
 static int ftgmac100_probe(struct platform_device *pdev)
 {
        struct resource *res;
@@ -1830,6 +1851,9 @@ static int ftgmac100_probe(struct platform_device *pdev)
                        goto err_setup_mdio;
        }
 
+       if (priv->is_aspeed)
+               ftgmac100_setup_clk(priv);
+
        /* Default ring sizes */
        priv->rx_q_entries = priv->new_rx_q_entries = DEF_RX_QUEUE_ENTRIES;
        priv->tx_q_entries = priv->new_tx_q_entries = DEF_TX_QUEUE_ENTRIES;
@@ -1883,6 +1907,8 @@ static int ftgmac100_remove(struct platform_device *pdev)
 
        unregister_netdev(netdev);
 
+       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.
         */