net: stmmac: visconti: convert to set_clk_tx_rate() method

Convert visconti to use the set_clk_tx_rate() method. By doing so,
the GMAC control register will already have been updated (unlike with
the fix_mac_speed() method) so this code can be removed while porting
to the set_clk_tx_rate() method.

There is also no need for the spinlock, and has never been - neither
fix_mac_speed() nor set_clk_tx_rate() can be called by more than one
thread at a time, so the lock does nothing useful.

Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Acked-by: Nobuhiro Iwamatsu <nobuhiro1.iwamatsu@toshiba.co.jp>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Link: https://patch.msgid.link/E1u5SiQ-001I0B-OQ@rmk-PC.armlinux.org.uk
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Author: Russell King (Oracle)

drivers/net/ethernet/stmicro/stmmac/dwmac-visconti.c

@@ -51,21 +51,14 @@ struct visconti_eth {
 	u32 phy_intf_sel;
 	struct clk *phy_ref_clk;
 	struct device *dev;
-	spinlock_t lock; /* lock to protect register update */
 };
 
-static void visconti_eth_fix_mac_speed(void *priv, int speed, unsigned int mode)
+static int visconti_eth_set_clk_tx_rate(void *bsp_priv, struct clk *clk_tx_i,
+					phy_interface_t interface, int speed)
 {
-	struct visconti_eth *dwmac = priv;
+	struct visconti_eth *dwmac = bsp_priv;
 	struct net_device *netdev = dev_get_drvdata(dwmac->dev);
 	unsigned int val, clk_sel_val = 0;
-	unsigned long flags;
-
-	spin_lock_irqsave(&dwmac->lock, flags);
-
-	/* adjust link */
-	val = readl(dwmac->reg + MAC_CTRL_REG);
-	val &= ~(GMAC_CONFIG_PS | GMAC_CONFIG_FES);
 
 	switch (speed) {
 	case SPEED_1000:
@@ -77,24 +70,19 @@ static void visconti_eth_fix_mac_speed(void *priv, int speed, unsigned int mode)
 			clk_sel_val = ETHER_CLK_SEL_FREQ_SEL_25M;
 		if (dwmac->phy_intf_sel == ETHER_CONFIG_INTF_RMII)
 			clk_sel_val = ETHER_CLK_SEL_DIV_SEL_2;
-		val |= GMAC_CONFIG_PS | GMAC_CONFIG_FES;
 		break;
 	case SPEED_10:
 		if (dwmac->phy_intf_sel == ETHER_CONFIG_INTF_RGMII)
 			clk_sel_val = ETHER_CLK_SEL_FREQ_SEL_2P5M;
 		if (dwmac->phy_intf_sel == ETHER_CONFIG_INTF_RMII)
 			clk_sel_val = ETHER_CLK_SEL_DIV_SEL_20;
-		val |= GMAC_CONFIG_PS;
 		break;
 	default:
 		/* No bit control */
 		netdev_err(netdev, "Unsupported speed request (%d)", speed);
-		spin_unlock_irqrestore(&dwmac->lock, flags);
-		return;
+		return -EINVAL;
 	}
 
-	writel(val, dwmac->reg + MAC_CTRL_REG);
-
 	/* Stop internal clock */
 	val = readl(dwmac->reg + REG_ETHER_CLOCK_SEL);
 	val &= ~(ETHER_CLK_SEL_RMII_CLK_EN | ETHER_CLK_SEL_RX_TX_CLK_EN);
@@ -136,7 +124,7 @@ static void visconti_eth_fix_mac_speed(void *priv, int speed, unsigned int mode)
 		break;
 	}
 
-	spin_unlock_irqrestore(&dwmac->lock, flags);
+	return 0;
 }
 
 static int visconti_eth_init_hw(struct platform_device *pdev, struct plat_stmmacenet_data *plat_dat)
@@ -228,11 +216,10 @@ static int visconti_eth_dwmac_probe(struct platform_device *pdev)
 	if (!dwmac)
 		return -ENOMEM;
 
-	spin_lock_init(&dwmac->lock);
 	dwmac->reg = stmmac_res.addr;
 	dwmac->dev = &pdev->dev;
 	plat_dat->bsp_priv = dwmac;
-	plat_dat->fix_mac_speed = visconti_eth_fix_mac_speed;
+	plat_dat->set_clk_tx_rate = visconti_eth_set_clk_tx_rate;
 
 	ret = visconti_eth_clock_probe(pdev, plat_dat);
 	if (ret)