Commit cc4efd7e authored by Martin Blumenstingl's avatar Martin Blumenstingl
Browse files

net: stmmac: dwmac-meson: Manage the "ethernet" clock 



Meson6 and Meson8 (both use the same glue registers on top of the DWMAC
IP) have a dedicated Ethernet clock. For RMII mode the SoC has an input
for an external RMII reference clock signal (which can be provided by
either the PHY or an external oscillator). This clock needs to run at
50MHz because the additional glue registers can divide by 2 - to achieve
25MHz for 100Mbit/s line speed, or 20 - to achieve 2.5MHz for 10Mbit/s
line speed.

Set the correct frequency for this clock and enable it during init. Also
enable the ETHMAC_DIV_EN bit which enables the divider in the glue
registers, based on the Ethernet clock input.

Signed-off-by: default avatarMartin Blumenstingl <martin.blumenstingl@googlemail.com>
parent 4b2e9ce5

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

+41 −1
Original line number Diff line number Diff line
@@ -5,6 +5,7 @@ 
 * Copyright (C) 2014 Beniamino Galvani <b.galvani@gmail.com>

 */



#include <linux/clk.h>

#include <linux/device.h>

#include <linux/ethtool.h>

#include <linux/io.h>
@@ -15,11 +16,14 @@ 


#include "stmmac_platform.h"



#define ETHMAC_DIV_EN		BIT(0)

/* divides the input clock by 20 (= 0x0) or 2 (= 0x1) */

#define ETHMAC_SPEED_100	BIT(1)



struct meson_dwmac {

	struct device	*dev;

	void __iomem	*reg;

	struct clk	*ethernet_clk;

};



static void meson6_dwmac_fix_mac_speed(void *priv, unsigned int speed)
@@ -41,6 +45,30 @@ static void meson6_dwmac_fix_mac_speed(void *priv, unsigned int speed) 
	writel(val, dwmac->reg);

}



static int meson6_dwmac_init(struct meson_dwmac *dwmac)

{

	int ret;



	ret = clk_set_rate(dwmac->ethernet_clk, 50 * 1000 * 1000);

	if (ret)

		return ret;



	ret = clk_prepare_enable(dwmac->ethernet_clk);

	if (ret)

		return ret;



	writel(readl(dwmac->reg) | ETHMAC_DIV_EN, dwmac->reg);



	return 0;

}



static void meson6_dwmac_exit(struct meson_dwmac *dwmac)

{

	writel(readl(dwmac->reg) & ~ETHMAC_DIV_EN, dwmac->reg);



	clk_disable_unprepare(dwmac->ethernet_clk);

}



static int meson6_dwmac_probe(struct platform_device *pdev)

{

	struct plat_stmmacenet_data *plat_dat;
@@ -68,15 +96,27 @@ static int meson6_dwmac_probe(struct platform_device *pdev) 
		goto err_remove_config_dt;

	}



	dwmac->ethernet_clk = devm_clk_get_optional(&pdev->dev, "ethernet");

	if (IS_ERR(dwmac->ethernet_clk)) {

		ret = PTR_ERR(dwmac->ethernet_clk);

		goto err_remove_config_dt;

	}



	plat_dat->bsp_priv = dwmac;

	plat_dat->fix_mac_speed = meson6_dwmac_fix_mac_speed;



	ret = meson6_dwmac_init(dwmac);

	if (ret)

		return ret;



	ret = stmmac_dvr_probe(&pdev->dev, plat_dat, &stmmac_res);

	if (ret)

		goto err_remove_config_dt;

		goto err_exit_dwmac;



	return 0;



err_exit_dwmac:

	meson6_dwmac_exit(dwmac);

err_remove_config_dt:

	stmmac_remove_config_dt(pdev, plat_dat);

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