drivers: net: cpsw-phy-sel: Add new driver for phy mode selection for cpsw

The cpsw currently lacks code to properly set up the hardware interface
mode on AM33xx. Other platforms might be equally affected.

Usually, the bootloader will configure the control module register, so
probably that's why such support wasn't needed in the past. In suspend
mode though, this register is modified, and so it needs reprogramming
after resume.

This patch adds a new driver in which hardware interface can configure
correct register bits when the slave is opened.

The AM33xx also has a bit for each slave to configure the RMII reference
clock direction. Setting it is now supported by a per-slave DT property.

This code path introducted by this patch is currently exclusive for
am33xx and same can be extened to various platforms via the DT compatibility
property.
Signed-off-by: Mugunthan V N <mugunthanvnm@ti.com>
Tested-by: Daniel Mack <zonque@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Documentation/devicetree/bindings/net/cpsw-phy-sel.txt

+TI CPSW Phy mode Selection Device Tree Bindings
+-----------------------------------------------
+
+Required properties:
+- compatible		: Should be "ti,am3352-cpsw-phy-sel"
+- reg			: physical base address and size of the cpsw
+			  registers map
+- reg-names		: names of the register map given in "reg" node
+
+Optional properties:
+-rmii-clock-ext		: If present, the driver will configure the RMII
+			  interface to external clock usage
+
+Examples:
+
+	phy_sel: cpsw-phy-sel@44e10650 {
+		compatible = "ti,am3352-cpsw-phy-sel";
+		reg= <0x44e10650 0x4>;
+		reg-names = "gmii-sel";
+	};
+
+(or)
+	phy_sel: cpsw-phy-sel@44e10650 {
+		compatible = "ti,am3352-cpsw-phy-sel";
+		reg= <0x44e10650 0x4>;
+		reg-names = "gmii-sel";
+		rmii-clock-ext;
+	};

drivers/net/ethernet/ti/Kconfig

@@ -49,11 +49,19 @@ config TI_DAVINCI_CPDMA
 	  To compile this driver as a module, choose M here: the module
 	  will be called davinci_cpdma.  This is recommended.
 
+config TI_CPSW_PHY_SEL
+	boolean "TI CPSW Switch Phy sel Support"
+	depends on TI_CPSW
+	---help---
+	  This driver supports configuring of the phy mode connected to
+	  the CPSW.
+
 config TI_CPSW
 	tristate "TI CPSW Switch Support"
 	depends on ARM && (ARCH_DAVINCI || SOC_AM33XX)
 	select TI_DAVINCI_CPDMA
 	select TI_DAVINCI_MDIO
+	select TI_CPSW_PHY_SEL
 	---help---
 	  This driver supports TI's CPSW Ethernet Switch.
 

drivers/net/ethernet/ti/Makefile

@@ -7,5 +7,6 @@ obj-$(CONFIG_CPMAC) += cpmac.o
 obj-$(CONFIG_TI_DAVINCI_EMAC) += davinci_emac.o
 obj-$(CONFIG_TI_DAVINCI_MDIO) += davinci_mdio.o
 obj-$(CONFIG_TI_DAVINCI_CPDMA) += davinci_cpdma.o
+obj-$(CONFIG_TI_CPSW_PHY_SEL) += cpsw-phy-sel.o
 obj-$(CONFIG_TI_CPSW) += ti_cpsw.o
 ti_cpsw-y := cpsw_ale.o cpsw.o cpts.o

drivers/net/ethernet/ti/cpsw-phy-sel.c

+/* Texas Instruments Ethernet Switch Driver
+ *
+ * Copyright (C) 2013 Texas Instruments
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed "as is" WITHOUT ANY WARRANTY of any
+ * kind, whether express or implied; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/platform_device.h>
+#include <linux/module.h>
+#include <linux/netdevice.h>
+#include <linux/phy.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+
+#include "cpsw.h"
+
+/* AM33xx SoC specific definitions for the CONTROL port */
+#define AM33XX_GMII_SEL_MODE_MII	0
+#define AM33XX_GMII_SEL_MODE_RMII	1
+#define AM33XX_GMII_SEL_MODE_RGMII	2
+
+#define AM33XX_GMII_SEL_RMII2_IO_CLK_EN	BIT(7)
+#define AM33XX_GMII_SEL_RMII1_IO_CLK_EN	BIT(6)
+
+struct cpsw_phy_sel_priv {
+	struct device	*dev;
+	u32 __iomem	*gmii_sel;
+	bool		rmii_clock_external;
+	void (*cpsw_phy_sel)(struct cpsw_phy_sel_priv *priv,
+			     phy_interface_t phy_mode, int slave);
+};
+
+
+static void cpsw_gmii_sel_am3352(struct cpsw_phy_sel_priv *priv,
+				 phy_interface_t phy_mode, int slave)
+{
+	u32 reg;
+	u32 mask;
+	u32 mode = 0;
+
+	reg = readl(priv->gmii_sel);
+
+	switch (phy_mode) {
+	case PHY_INTERFACE_MODE_RMII:
+		mode = AM33XX_GMII_SEL_MODE_RMII;
+		break;
+
+	case PHY_INTERFACE_MODE_RGMII:
+	case PHY_INTERFACE_MODE_RGMII_ID:
+	case PHY_INTERFACE_MODE_RGMII_RXID:
+	case PHY_INTERFACE_MODE_RGMII_TXID:
+		mode = AM33XX_GMII_SEL_MODE_RGMII;
+		break;
+
+	case PHY_INTERFACE_MODE_MII:
+	default:
+		mode = AM33XX_GMII_SEL_MODE_MII;
+		break;
+	};
+
+	mask = 0x3 << (slave * 2) | BIT(slave + 6);
+	mode <<= slave * 2;
+
+	if (priv->rmii_clock_external) {
+		if (slave == 0)
+			mode |= AM33XX_GMII_SEL_RMII1_IO_CLK_EN;
+		else
+			mode |= AM33XX_GMII_SEL_RMII2_IO_CLK_EN;
+	}
+
+	reg &= ~mask;
+	reg |= mode;
+
+	writel(reg, priv->gmii_sel);
+}
+
+static struct platform_driver cpsw_phy_sel_driver;
+static int match(struct device *dev, void *data)
+{
+	struct device_node *node = (struct device_node *)data;
+	return dev->of_node == node &&
+		dev->driver == &cpsw_phy_sel_driver.driver;
+}
+
+void cpsw_phy_sel(struct device *dev, phy_interface_t phy_mode, int slave)
+{
+	struct device_node *node;
+	struct cpsw_phy_sel_priv *priv;
+
+	node = of_get_child_by_name(dev->of_node, "cpsw-phy-sel");
+	if (!node) {
+		dev_err(dev, "Phy mode driver DT not found\n");
+		return;
+	}
+
+	dev = bus_find_device(&platform_bus_type, NULL, node, match);
+	priv = dev_get_drvdata(dev);
+
+	priv->cpsw_phy_sel(priv, phy_mode, slave);
+}
+EXPORT_SYMBOL_GPL(cpsw_phy_sel);
+
+static const struct of_device_id cpsw_phy_sel_id_table[] = {
+	{
+		.compatible	= "ti,am3352-cpsw-phy-sel",
+		.data		= &cpsw_gmii_sel_am3352,
+	},
+	{}
+};
+MODULE_DEVICE_TABLE(of, cpsw_phy_sel_id_table);
+
+static int cpsw_phy_sel_probe(struct platform_device *pdev)
+{
+	struct resource	*res;
+	const struct of_device_id *of_id;
+	struct cpsw_phy_sel_priv *priv;
+
+	of_id = of_match_node(cpsw_phy_sel_id_table, pdev->dev.of_node);
+	if (!of_id)
+		return -EINVAL;
+
+	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv) {
+		dev_err(&pdev->dev, "unable to alloc memory for cpsw phy sel\n");
+		return -ENOMEM;
+	}
+
+	priv->cpsw_phy_sel = of_id->data;
+
+	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "gmii-sel");
+	priv->gmii_sel = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(priv->gmii_sel))
+		return PTR_ERR(priv->gmii_sel);
+
+	if (of_find_property(pdev->dev.of_node, "rmii-clock-ext", NULL))
+		priv->rmii_clock_external = true;
+
+	dev_set_drvdata(&pdev->dev, priv);
+
+	return 0;
+}
+
+static struct platform_driver cpsw_phy_sel_driver = {
+	.probe		= cpsw_phy_sel_probe,
+	.driver		= {
+		.name	= "cpsw-phy-sel",
+		.owner	= THIS_MODULE,
+		.of_match_table = of_match_ptr(cpsw_phy_sel_id_table),
+	},
+};
+
+module_platform_driver(cpsw_phy_sel_driver);
+MODULE_AUTHOR("Mugunthan V N <mugunthanvnm@ti.com>");
+MODULE_LICENSE("GPL v2");

drivers/net/ethernet/ti/cpsw.h

@@ -39,4 +39,6 @@ struct cpsw_platform_data {
 	bool	dual_emac;	/* Enable Dual EMAC mode */
 };
 
+void cpsw_phy_sel(struct device *dev, phy_interface_t phy_mode, int slave);
+
 #endif /* __CPSW_H__ */