drivers: phy: add generic PHY framework

The PHY framework provides a set of APIs to control a PHY. This API is
derived from the linux version of the generic PHY framework.
Currently the API supports init(), deinit(), power_on, power_off() and
reset(). The framework provides a way to get a reference to a phy from the
device-tree.

Signed-off-by: Jean-Jacques Hiblot <jjhiblot@ti.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

drivers/Kconfig

@@ -54,6 +54,8 @@ source "drivers/pci/Kconfig"
 
 source "drivers/pcmcia/Kconfig"
 
+source "drivers/phy/Kconfig"
+
 source "drivers/phy/marvell/Kconfig"
 
 source "drivers/pinctrl/Kconfig"

drivers/Makefile

@@ -5,6 +5,7 @@
 obj-$(CONFIG_$(SPL_TPL_)DM)	+= core/
 obj-$(CONFIG_$(SPL_)CLK)	+= clk/
 obj-$(CONFIG_$(SPL_)LED)	+= led/
+obj-$(CONFIG_$(SPL_)PHY)	+= phy/
 obj-$(CONFIG_$(SPL_)PINCTRL)	+= pinctrl/
 obj-$(CONFIG_$(SPL_)RAM)	+= ram/
 

drivers/phy/Kconfig

@@ -0,0 +1,36 @@
+
+menu "PHY Subsystem"
+
+config PHY
+	bool "PHY Core"
+	depends on DM
+	help
+	  PHY support.
+
+	  This framework is designed to provide a generic interface for PHY
+	  devices. PHY devices are dedicated hardware that handle the physical
+	  layer of the protocols in the OSI model.
+	  PHYs are commonly used for high speed interfaces such as Serial-ATA
+	  or PCI express.
+	  The API provides functions to initialize/deinitialize the
+	  PHY, power on/off the PHY, and reset the PHY. It's meant to be as
+	  compatible as possible with the equivalent framework found in the
+	  linux kernel.
+
+config SPL_PHY
+	bool "PHY Core in SPL"
+	depends on DM
+	help
+	  PHY support in SPL.
+
+	  This framework is designed to provide a generic interface for PHY
+	  devices. PHY devices are dedicated hardware that handle the physical
+	  layer of the protocols (https://en.wikipedia.org/wiki/OSI_model).
+	  PHYs are commonly used for high speed interfaces such as Serial-ATA
+	  or PCI express.
+	  The API provides functions to initialize/deinitialize the
+	  PHY, power on/off the PHY, and reset the PHY. It's meant to be as
+	  compatible as possible with the equivalent framework found in the
+	  linux kernel.
+
+endmenu

drivers/phy/Makefile

@@ -0,0 +1,8 @@
+#
+# Copyright (C) 2017 Texas Instruments Incorporated - http://www.ti.com/
+# Written by Jean-Jacques Hiblot  <jjhiblot@ti.com>
+#
+# SPDX-License-Identifier:	GPL-2.0+
+#
+
+obj-$(CONFIG_$(SPL_)PHY) += phy-uclass.o

drivers/phy/phy-uclass.c

@@ -0,0 +1,139 @@
+/*
+ * Copyright (C) 2017 Texas Instruments Incorporated - http://www.ti.com/
+ * Written by Jean-Jacques Hiblot  <jjhiblot@ti.com>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <generic-phy.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+static inline struct phy_ops *phy_dev_ops(struct udevice *dev)
+{
+	return (struct phy_ops *)dev->driver->ops;
+}
+
+static int generic_phy_xlate_offs_flags(struct phy *phy,
+				 struct fdtdec_phandle_args *args)
+{
+	debug("%s(phy=%p)\n", __func__, phy);
+
+	if (args->args_count > 1) {
+		debug("Invaild args_count: %d\n", args->args_count);
+		return -EINVAL;
+	}
+
+	if (args->args_count)
+		phy->id = args->args[0];
+	else
+		phy->id = 0;
+
+
+	return 0;
+}
+
+int generic_phy_get_by_index(struct udevice *dev, int index,
+			     struct phy *phy)
+{
+	struct fdtdec_phandle_args args;
+	struct phy_ops *ops;
+	int ret;
+	struct udevice *phydev;
+
+	debug("%s(dev=%p, index=%d, phy=%p)\n", __func__, dev, index, phy);
+
+	assert(phy);
+	ret = fdtdec_parse_phandle_with_args(gd->fdt_blob, dev_of_offset(dev),
+					     "phys", "#phy-cells", 0, index,
+					     &args);
+	if (ret) {
+		debug("%s: fdtdec_parse_phandle_with_args failed: err=%d\n",
+		      __func__, ret);
+		return ret;
+	}
+
+	ret = uclass_get_device_by_of_offset(UCLASS_PHY, args.node, &phydev);
+	if (ret) {
+		debug("%s: uclass_get_device_by_of_offset failed: err=%d\n",
+		      __func__, ret);
+		return ret;
+	}
+
+	phy->dev = phydev;
+
+	ops = phy_dev_ops(phydev);
+
+	if (ops->of_xlate)
+		ret = ops->of_xlate(phy, &args);
+	else
+		ret = generic_phy_xlate_offs_flags(phy, &args);
+	if (ret) {
+		debug("of_xlate() failed: %d\n", ret);
+		goto err;
+	}
+
+	return 0;
+
+err:
+	return ret;
+}
+
+int generic_phy_get_by_name(struct udevice *dev, const char *phy_name,
+			    struct phy *phy)
+{
+	int index;
+
+	debug("%s(dev=%p, name=%s, phy=%p)\n", __func__, dev, phy_name, phy);
+
+	index = fdt_stringlist_search(gd->fdt_blob, dev_of_offset(dev),
+				      "phy-names", phy_name);
+	if (index < 0) {
+		debug("fdt_stringlist_search() failed: %d\n", index);
+		return index;
+	}
+
+	return generic_phy_get_by_index(dev, index, phy);
+}
+
+int generic_phy_init(struct phy *phy)
+{
+	struct phy_ops const *ops = phy_dev_ops(phy->dev);
+
+	return ops->init ? ops->init(phy) : 0;
+}
+
+int generic_phy_reset(struct phy *phy)
+{
+	struct phy_ops const *ops = phy_dev_ops(phy->dev);
+
+	return ops->reset ? ops->reset(phy) : 0;
+}
+
+int generic_phy_exit(struct phy *phy)
+{
+	struct phy_ops const *ops = phy_dev_ops(phy->dev);
+
+	return ops->exit ? ops->exit(phy) : 0;
+}
+
+int generic_phy_power_on(struct phy *phy)
+{
+	struct phy_ops const *ops = phy_dev_ops(phy->dev);
+
+	return ops->power_on ? ops->power_on(phy) : 0;
+}
+
+int generic_phy_power_off(struct phy *phy)
+{
+	struct phy_ops const *ops = phy_dev_ops(phy->dev);
+
+	return ops->power_off ? ops->power_off(phy) : 0;
+}
+
+UCLASS_DRIVER(phy) = {
+	.id		= UCLASS_PHY,
+	.name		= "phy",
+};

include/dm/uclass-id.h

@@ -56,6 +56,7 @@ enum uclass_id {
 	UCLASS_PCH,		/* x86 platform controller hub */
 	UCLASS_PCI,		/* PCI bus */
 	UCLASS_PCI_GENERIC,	/* Generic PCI bus device */
+	UCLASS_PHY,		/* Physical Layer (PHY) device */
 	UCLASS_PINCONFIG,	/* Pin configuration node device */
 	UCLASS_PINCTRL,		/* Pinctrl (pin muxing/configuration) device */
 	UCLASS_PMIC,		/* PMIC I/O device */

include/generic-phy.h

@@ -0,0 +1,224 @@
+/*
+ * Copyright (C) 2017 Texas Instruments Incorporated - http://www.ti.com/
+ * Written by Jean-Jacques Hiblot  <jjhiblot@ti.com>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#ifndef __GENERIC_PHY_H
+#define __GENERIC_PHY_H
+
+
+/**
+ * struct phy - A handle to (allowing control of) a single phy port.
+ *
+ * Clients provide storage for phy handles. The content of the structure is
+ * managed solely by the PHY API and PHY drivers. A phy struct is
+ * initialized by "get"ing the phy struct. The phy struct is passed to all
+ * other phy APIs to identify which PHY port to operate upon.
+ *
+ * @dev: The device which implements the PHY port.
+ * @id: The PHY ID within the provider.
+ *
+ */
+struct phy {
+	struct udevice *dev;
+	unsigned long id;
+};
+
+/*
+ * struct udevice_ops - set of function pointers for phy operations
+ * @init: operation to be performed for initializing phy (optional)
+ * @exit: operation to be performed while exiting (optional)
+ * @reset: reset the phy (optional).
+ * @power_on: powering on the phy (optional)
+ * @power_off: powering off the phy (optional)
+ */
+struct phy_ops {
+	/**
+	 * of_xlate - Translate a client's device-tree (OF) phy specifier.
+	 *
+	 * The PHY core calls this function as the first step in implementing
+	 * a client's generic_phy_get_by_*() call.
+	 *
+	 * If this function pointer is set to NULL, the PHY core will use a
+	 * default implementation, which assumes #phy-cells = <0> or
+	 * #phy-cells = <1>, and in the later case that the DT cell
+	 * contains a simple integer PHY port ID.
+	 *
+	 * @phy:	The phy struct to hold the translation result.
+	 * @args:	The phy specifier values from device tree.
+	 * @return 0 if OK, or a negative error code.
+	 */
+	int	(*of_xlate)(struct phy *phy,
+			struct fdtdec_phandle_args *args);
+
+	/**
+	 * init - initialize the hardware.
+	 *
+	 * Hardware intialization should not be done in during probe() but
+	 * should be implemented in this init() function. It could be starting
+	 * PLL, taking a controller out of reset, routing, etc. This function
+	 * is typically called only once per PHY port.
+	 * If power_on() is not implemented, it must power up the phy.
+	 *
+	 * @phy:	the PHY port to initialize
+	 * @return 0 if OK, or a negative error code.
+	 */
+	int	(*init)(struct phy *phy);
+
+	/**
+	* exit - de-initialize the PHY device
+	*
+	* Hardware de-intialization should be done here. Every step done in
+	* init() should be undone here.
+	* This could be used to suspend the phy to reduce power consumption or
+	* to put the phy in a known condition before booting the OS (though it
+	* is NOT called automatically before booting the OS)
+	* If power_off() is not implemented, it must power down the phy.
+	*
+	* @phy:	PHY port to be de-initialized
+	* @return 0 if OK, or a negative error code
+	*/
+	int	(*exit)(struct phy *phy);
+
+	/**
+	* reset - resets a PHY device without shutting down
+	*
+	* @phy:	PHY port to be reset
+	*
+	* During runtime, the PHY may need to be reset in order to
+	* re-establish connection etc without being shut down or exit.
+	*
+	* @return 0 if OK, or a negative error code
+	*/
+	int	(*reset)(struct phy *phy);
+
+	/**
+	* power_on - power on a PHY device
+	*
+	* @phy:	PHY port to be powered on
+	*
+	* During runtime, the PHY may need to be powered on or off several
+	* times. This function is used to power on the PHY. It relies on the
+	* setup done in init(). If init() is not implemented, it must take care
+	* of setting up the context (PLLs, ...)
+	*
+	* @return 0 if OK, or a negative error code
+	*/
+	int	(*power_on)(struct phy *phy);
+
+	/**
+	* power_off - power off a PHY device
+	*
+	* @phy:	PHY port to be powered off
+	*
+	* During runtime, the PHY may need to be powered on or off several
+	* times. This function is used to power off the PHY. Except if
+	* init()/deinit() are not implemented, it must not de-initialize
+	* everything.
+	*
+	* @return 0 if OK, or a negative error code
+	*/
+	int	(*power_off)(struct phy *phy);
+};
+
+
+/**
+ * generic_phy_init() - initialize the PHY port
+ *
+ * @phy:	the PHY port to initialize
+ * @return 0 if OK, or a negative error code
+ */
+int generic_phy_init(struct phy *phy);
+
+/**
+ * generic_phy_init() - de-initialize the PHY device
+ *
+ * @phy:	PHY port to be de-initialized
+ * @return 0 if OK, or a negative error code
+ */
+int generic_phy_exit(struct phy *phy);
+
+/**
+ * generic_phy_reset() - resets a PHY device without shutting down
+ *
+ * @phy:	PHY port to be reset
+ *@return 0 if OK, or a negative error code
+ */
+int generic_phy_reset(struct phy *phy);
+
+/**
+ * generic_phy_power_on() - power on a PHY device
+ *
+ * @phy:	PHY port to be powered on
+ * @return 0 if OK, or a negative error code
+ */
+int generic_phy_power_on(struct phy *phy);
+
+/**
+ * generic_phy_power_off() - power off a PHY device
+ *
+ * @phy:	PHY port to be powered off
+ * @return 0 if OK, or a negative error code
+ */
+int generic_phy_power_off(struct phy *phy);
+
+
+/**
+ * generic_phy_get_by_index() - Get a PHY device by integer index.
+ *
+ * @user:	the client device
+ * @index:	The index in the list of available PHYs
+ * @phy:	A pointer to the PHY port
+ *
+ * This looks up a PHY device for a client device based on its position in the
+ * list of the possible PHYs.
+ *
+ * example:
+ * usb1: usb_otg_ss@xxx {
+ *       compatible = "xxx";
+ *       reg = <xxx>;
+ *   .
+ *   .
+ *   phys = <&usb2_phy>, <&usb3_phy>;
+ *   .
+ *   .
+ * };
+ * the USB2 phy can be accessed by passing index '0' and the USB3 phy can
+ * be accessed by passing index '1'
+ *
+ * @return 0 if OK, or a negative error code
+ */
+int generic_phy_get_by_index(struct udevice *user, int index,
+			     struct phy *phy);
+
+/**
+ * generic_phy_get_by_name() - Get a PHY device by its name.
+ *
+ * @user:	the client device
+ * @phy_name:	The name of the PHY in the list of possible PHYs
+ * @phy:	A pointer to the PHY port
+ *
+ * This looks up a PHY device for a client device in the
+ * list of the possible PHYs based on its name.
+ *
+ * example:
+ * usb1: usb_otg_ss@xxx {
+ *       compatible = "xxx";
+ *       reg = <xxx>;
+ *   .
+ *   .
+ *   phys = <&usb2_phy>, <&usb3_phy>;
+ *   phy-names = "usb2phy", "usb3phy";
+ *   .
+ *   .
+ * };
+ * the USB3 phy can be accessed using "usb3phy", and USB2 by using "usb2phy"
+ *
+ * @return 0 if OK, or a negative error code
+ */
+int generic_phy_get_by_name(struct udevice *user, const char *phy_name,
+			    struct phy *phy);
+
+#endif /*__GENERIC_PHY_H */