ethernet: arc: Add support for Rockchip SoC layer device tree bindings

This patch defines a platform glue layer for Rockchip SoCs which
support arc-emac driver. It ensures that regulator for the rmii is on
before trying to connect to the ethernet controller. It applies right
speed and mode changes to the grf when ethernet settings change.

Signed-off-by: Romain Perier <romain.perier@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/arc/Kconfig

@@ -32,4 +32,14 @@ config ARC_EMAC
 	  non-standard on-chip ethernet device ARC EMAC 10/100 is used.
 	  Say Y here if you have such a board.  If unsure, say N.
 
+config EMAC_ROCKCHIP
+	tristate "Rockchip EMAC support"
+	select ARC_EMAC_CORE
+	depends on OF_IRQ && OF_NET && REGULATOR
+	---help---
+	  Support for Rockchip RK3066/RK3188 EMAC ethernet controllers.
+	  This selects Rockchip SoC glue layer support for the
+	  emac device driver. This driver is used for RK3066/RK3188
+	  EMAC ethernet controller.
+
 endif # NET_VENDOR_ARC

drivers/net/ethernet/arc/Makefile

@@ -5,3 +5,4 @@
 arc_emac-objs := emac_main.o emac_mdio.o
 obj-$(CONFIG_ARC_EMAC_CORE) += arc_emac.o
 obj-$(CONFIG_ARC_EMAC) += emac_arc.o
+obj-$(CONFIG_EMAC_ROCKCHIP) += emac_rockchip.o

drivers/net/ethernet/arc/emac.h

@@ -123,9 +123,11 @@ struct buffer_state {
  * @speed:	PHY's last set speed.
  */
 struct arc_emac_priv {
-	/* Devices */
 	const char *drv_name;
 	const char *drv_version;
+	void (*set_mac_speed)(void *priv, unsigned int speed);
+
+	/* Devices */
 	struct device *dev;
 	struct phy_device *phy_dev;
 	struct mii_bus *bus;

drivers/net/ethernet/arc/emac_main.c

@@ -48,6 +48,8 @@ static void arc_emac_adjust_link(struct net_device *ndev)
 	if (priv->speed != phy_dev->speed) {
 		priv->speed = phy_dev->speed;
 		state_changed = 1;
+		if (priv->set_mac_speed)
+			priv->set_mac_speed(priv, priv->speed);
 	}
 
 	if (priv->duplex != phy_dev->duplex) {

drivers/net/ethernet/arc/emac_rockchip.c

@@ -0,0 +1,228 @@
+/**
+ * emac-rockchip.c - Rockchip EMAC specific glue layer
+ *
+ * Copyright (C) 2014 Romain Perier <romain.perier@gmail.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/etherdevice.h>
+#include <linux/mfd/syscon.h>
+#include <linux/module.h>
+#include <linux/of_net.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/regulator/consumer.h>
+
+#include "emac.h"
+
+#define DRV_NAME        "rockchip_emac"
+#define DRV_VERSION     "1.0"
+
+#define GRF_MODE_MII		(1UL << 0)
+#define GRF_MODE_RMII		(0UL << 0)
+#define GRF_SPEED_10M		(0UL << 1)
+#define GRF_SPEED_100M		(1UL << 1)
+#define GRF_SPEED_ENABLE_BIT	(1UL << 17)
+#define GRF_MODE_ENABLE_BIT	(1UL << 16)
+
+struct emac_rockchip_soc_data {
+	int grf_offset;
+};
+
+struct rockchip_priv_data {
+	struct arc_emac_priv emac;
+	struct regmap *grf;
+	const struct emac_rockchip_soc_data *soc_data;
+	struct regulator *regulator;
+	struct clk *refclk;
+};
+
+static void emac_rockchip_set_mac_speed(void *priv, unsigned int speed)
+{
+	struct rockchip_priv_data *emac = priv;
+	u32 data;
+	int err = 0;
+
+	/* write-enable bits */
+	data = GRF_SPEED_ENABLE_BIT;
+
+	switch(speed) {
+	case 10:
+		data |= GRF_SPEED_10M;
+		break;
+	case 100:
+		data |= GRF_SPEED_100M;
+		break;
+	default:
+		pr_err("speed %u not supported\n", speed);
+		return;
+	}
+
+	err = regmap_write(emac->grf, emac->soc_data->grf_offset, data);
+	if (err)
+		pr_err("unable to apply speed %u to grf (%d)\n", speed, err);
+}
+
+static const struct emac_rockchip_soc_data emac_rockchip_dt_data[] = {
+	{ .grf_offset = 0x154 }, /* rk3066 */
+	{ .grf_offset = 0x0a4 }, /* rk3188 */
+};
+
+static const struct of_device_id emac_rockchip_dt_ids[] = {
+	{ .compatible = "rockchip,rk3066-emac", .data = &emac_rockchip_dt_data[0] },
+	{ .compatible = "rockchip,rk3188-emac", .data = &emac_rockchip_dt_data[1] },
+	{ /* Sentinel */ }
+};
+
+MODULE_DEVICE_TABLE(of, emac_rockchip_dt_ids);
+
+static int emac_rockchip_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct net_device *ndev;
+	struct rockchip_priv_data *priv;
+	const struct of_device_id *match;
+	u32 data;
+	int err, interface;
+
+	if (!pdev->dev.of_node)
+		return -ENODEV;
+
+	ndev = alloc_etherdev(sizeof(struct rockchip_priv_data));
+	if (!ndev)
+		return -ENOMEM;
+	platform_set_drvdata(pdev, ndev);
+	SET_NETDEV_DEV(ndev, dev);
+
+	priv = netdev_priv(ndev);
+	priv->emac.drv_name = DRV_NAME;
+	priv->emac.drv_version = DRV_VERSION;
+	priv->emac.set_mac_speed = emac_rockchip_set_mac_speed;
+
+	interface = of_get_phy_mode(dev->of_node);
+
+	/* RK3066 and RK3188 SoCs only support RMII */
+	if (interface != PHY_INTERFACE_MODE_RMII) {
+		dev_err(dev, "unsupported phy interface mode %d\n", interface);
+		err = -ENOTSUPP;
+		goto out_netdev;
+	}
+
+	priv->grf = syscon_regmap_lookup_by_phandle(dev->of_node, "rockchip,grf");
+	if (IS_ERR(priv->grf)) {
+		dev_err(dev, "failed to retrieve global register file (%ld)\n", PTR_ERR(priv->grf));
+		err = PTR_ERR(priv->grf);
+		goto out_netdev;
+	}
+
+	match = of_match_node(emac_rockchip_dt_ids, dev->of_node);
+	priv->soc_data = match->data;
+
+	priv->emac.clk = devm_clk_get(dev, "hclk");
+	if (IS_ERR(priv->emac.clk)) {
+		dev_err(dev, "failed to retrieve host clock (%ld)\n", PTR_ERR(priv->emac.clk));
+		err = PTR_ERR(priv->emac.clk);
+		goto out_netdev;
+	}
+
+	priv->refclk = devm_clk_get(dev, "macref");
+	if (IS_ERR(priv->refclk)) {
+		dev_err(dev, "failed to retrieve reference clock (%ld)\n", PTR_ERR(priv->refclk));
+		err = PTR_ERR(priv->refclk);
+		goto out_netdev;
+	}
+
+	err = clk_prepare_enable(priv->refclk);
+	if (err) {
+		dev_err(dev, "failed to enable reference clock (%d)\n", err);
+		goto out_netdev;
+	}
+
+	/* Optional regulator for PHY */
+	priv->regulator = devm_regulator_get_optional(dev, "phy");
+	if (IS_ERR(priv->regulator)) {
+		if (PTR_ERR(priv->regulator) == -EPROBE_DEFER)
+			return -EPROBE_DEFER;
+		dev_err(dev, "no regulator found\n");
+		priv->regulator = NULL;
+	}
+
+	if (priv->regulator) {
+		err = regulator_enable(priv->regulator);
+		if (err) {
+			dev_err(dev, "failed to enable phy-supply (%d)\n", err);
+			goto out_clk_disable;
+		}
+	}
+
+	err = arc_emac_probe(ndev, interface);
+	if (err)
+		goto out_regulator_disable;
+
+	/* write-enable bits */
+	data = GRF_MODE_ENABLE_BIT | GRF_SPEED_ENABLE_BIT;
+
+	data |= GRF_SPEED_100M;
+	data |= GRF_MODE_RMII;
+
+	err = regmap_write(priv->grf, priv->soc_data->grf_offset, data);
+	if (err) {
+		dev_err(dev, "unable to apply initial settings to grf (%d)\n", err);
+		goto out_regulator_disable;
+	}
+
+	/* RMII interface needs always a rate of 50MHz */
+	err = clk_set_rate(priv->refclk, 50000000);
+	if (err)
+		dev_err(dev, "failed to change reference clock rate (%d)\n", err);
+	return 0;
+
+out_regulator_disable:
+	if (priv->regulator)
+		regulator_disable(priv->regulator);
+out_clk_disable:
+	clk_disable_unprepare(priv->refclk);
+out_netdev:
+	free_netdev(ndev);
+	return err;
+}
+
+static int emac_rockchip_remove(struct platform_device *pdev)
+{
+	struct net_device *ndev = platform_get_drvdata(pdev);
+	struct rockchip_priv_data *priv = netdev_priv(ndev);
+	int err;
+
+	clk_disable_unprepare(priv->refclk);
+
+	if (priv->regulator)
+		regulator_disable(priv->regulator);
+
+	err = arc_emac_remove(ndev);
+	free_netdev(ndev);
+	return err;
+}
+
+static struct platform_driver emac_rockchip_driver = {
+	.probe = emac_rockchip_probe,
+	.remove = emac_rockchip_remove,
+	.driver = {
+		.name = DRV_NAME,
+		.of_match_table  = emac_rockchip_dt_ids,
+	},
+};
+
+module_platform_driver(emac_rockchip_driver);
+
+MODULE_AUTHOR("Romain Perier <romain.perier@gmail.com>");
+MODULE_DESCRIPTION("Rockchip EMAC platform driver");
+MODULE_LICENSE("GPL");