From e1824dfe0d8e6bae55859eb016ce21b61d1b8c85 Mon Sep 17 00:00:00 2001 From: Soren Brinkmann Date: Tue, 10 Dec 2013 16:07:23 -0800 Subject: net: macb: Adjust tx_clk when link speed changes Adjust the ethernet clock according to the negotiated link speed. Signed-off-by: Soren Brinkmann Signed-off-by: David S. Miller --- drivers/net/ethernet/cadence/macb.c | 64 +++++++++++++++++++++++++++++++++++++ 1 file changed, 64 insertions(+) (limited to 'drivers/net/ethernet/cadence/macb.c') diff --git a/drivers/net/ethernet/cadence/macb.c b/drivers/net/ethernet/cadence/macb.c index 603844b1d483..419529a9309d 100644 --- a/drivers/net/ethernet/cadence/macb.c +++ b/drivers/net/ethernet/cadence/macb.c @@ -204,6 +204,47 @@ static int macb_mdio_reset(struct mii_bus *bus) return 0; } +/** + * macb_set_tx_clk() - Set a clock to a new frequency + * @clk Pointer to the clock to change + * @rate New frequency in Hz + * @dev Pointer to the struct net_device + */ +static void macb_set_tx_clk(struct clk *clk, int speed, struct net_device *dev) +{ + long ferr, rate, rate_rounded; + + switch (speed) { + case SPEED_10: + rate = 2500000; + break; + case SPEED_100: + rate = 25000000; + break; + case SPEED_1000: + rate = 125000000; + break; + default: + break; + } + + rate_rounded = clk_round_rate(clk, rate); + if (rate_rounded < 0) + return; + + /* RGMII allows 50 ppm frequency error. Test and warn if this limit + * is not satisfied. + */ + ferr = abs(rate_rounded - rate); + ferr = DIV_ROUND_UP(ferr, rate / 100000); + if (ferr > 5) + netdev_warn(dev, "unable to generate target frequency: %ld Hz\n", + rate); + + if (clk_set_rate(clk, rate_rounded)) + netdev_err(dev, "adjusting tx_clk failed.\n"); +} + static void macb_handle_link_change(struct net_device *dev) { struct macb *bp = netdev_priv(dev); @@ -251,6 +292,9 @@ static void macb_handle_link_change(struct net_device *dev) spin_unlock_irqrestore(&bp->lock, flags); + if (!IS_ERR(bp->tx_clk)) + macb_set_tx_clk(bp->tx_clk, phydev->speed, dev); + if (status_change) { if (phydev->link) { netif_carrier_on(dev); @@ -1805,6 +1849,8 @@ static int __init macb_probe(struct platform_device *pdev) goto err_out_free_dev; } + bp->tx_clk = devm_clk_get(&pdev->dev, "tx_clk"); + err = clk_prepare_enable(bp->pclk); if (err) { dev_err(&pdev->dev, "failed to enable pclk (%u)\n", err); @@ -1817,6 +1863,15 @@ static int __init macb_probe(struct platform_device *pdev) goto err_out_disable_pclk; } + if (!IS_ERR(bp->tx_clk)) { + err = clk_prepare_enable(bp->tx_clk); + if (err) { + dev_err(&pdev->dev, "failed to enable tx_clk (%u)\n", + err); + goto err_out_disable_hclk; + } + } + bp->regs = devm_ioremap(&pdev->dev, regs->start, resource_size(regs)); if (!bp->regs) { dev_err(&pdev->dev, "failed to map registers, aborting.\n"); @@ -1917,6 +1972,9 @@ static int __init macb_probe(struct platform_device *pdev) err_out_unregister_netdev: unregister_netdev(dev); err_out_disable_clocks: + if (!IS_ERR(bp->tx_clk)) + clk_disable_unprepare(bp->tx_clk); +err_out_disable_hclk: clk_disable_unprepare(bp->hclk); err_out_disable_pclk: clk_disable_unprepare(bp->pclk); @@ -1941,6 +1999,8 @@ static int __exit macb_remove(struct platform_device *pdev) kfree(bp->mii_bus->irq); mdiobus_free(bp->mii_bus); unregister_netdev(dev); + if (!IS_ERR(bp->tx_clk)) + clk_disable_unprepare(bp->tx_clk); clk_disable_unprepare(bp->hclk); clk_disable_unprepare(bp->pclk); free_netdev(dev); @@ -1959,6 +2019,8 @@ static int macb_suspend(struct device *dev) netif_carrier_off(netdev); netif_device_detach(netdev); + if (!IS_ERR(bp->tx_clk)) + clk_disable_unprepare(bp->tx_clk); clk_disable_unprepare(bp->hclk); clk_disable_unprepare(bp->pclk); @@ -1973,6 +2035,8 @@ static int macb_resume(struct device *dev) clk_prepare_enable(bp->pclk); clk_prepare_enable(bp->hclk); + if (!IS_ERR(bp->tx_clk)) + clk_prepare_enable(bp->tx_clk); netif_device_attach(netdev); -- cgit