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

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Date:   Tue, 10 Oct 2017 15:19:25 +1030
From:   Joel Stanley <joel@....id.au>
To:     "David S . Miller" <davem@...emloft.net>,
        Benjamin Herrenschmidt <benh@...nel.crashing.org>
Cc:     netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
        Andrew Jeffery <andrew@...id.au>
Subject: [PATCH] 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.

Signed-off-by: Joel Stanley <joel@....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