phy-stih407-usb.c

  1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * Copyright (C) 2014 STMicroelectronics
  4 *
  5 * STMicroelectronics Generic PHY driver for STiH407 USB2.
  6 *
  7 * Author: Giuseppe Cavallaro <peppe.cavallaro@st.com>
  8 */
  9#include <linux/platform_device.h>
 10#include <linux/io.h>
 11#include <linux/kernel.h>
 12#include <linux/module.h>
 13#include <linux/of.h>
 14#include <linux/of_platform.h>
 15#include <linux/clk.h>
 16#include <linux/regmap.h>
 17#include <linux/reset.h>
 18#include <linux/mfd/syscon.h>
 19#include <linux/phy/phy.h>
 20
 21#define PHYPARAM_REG	0
 22#define PHYCTRL_REG	1
 23
 24/* Default PHY_SEL and REFCLKSEL configuration */
 25#define STIH407_USB_PICOPHY_CTRL_PORT_CONF	0x6
 26#define STIH407_USB_PICOPHY_CTRL_PORT_MASK	0x1f
 27
 28/* ports parameters overriding */
 29#define STIH407_USB_PICOPHY_PARAM_DEF		0x39a4dc
 30#define STIH407_USB_PICOPHY_PARAM_MASK		0xffffffff
 31
 32struct stih407_usb2_picophy {
 33	struct phy *phy;
 34	struct regmap *regmap;
 35	struct device *dev;
 36	struct reset_control *rstc;
 37	struct reset_control *rstport;
 38	int ctrl;
 39	int param;
 40};
 41
 42static int stih407_usb2_pico_ctrl(struct stih407_usb2_picophy *phy_dev)
 43{
 44	reset_control_deassert(phy_dev->rstc);
 45
 46	return regmap_update_bits(phy_dev->regmap, phy_dev->ctrl,
 47				  STIH407_USB_PICOPHY_CTRL_PORT_MASK,
 48				  STIH407_USB_PICOPHY_CTRL_PORT_CONF);
 49}
 50
 51static int stih407_usb2_init_port(struct phy *phy)
 52{
 53	int ret;
 54	struct stih407_usb2_picophy *phy_dev = phy_get_drvdata(phy);
 55
 56	stih407_usb2_pico_ctrl(phy_dev);
 57
 58	ret = regmap_update_bits(phy_dev->regmap,
 59				 phy_dev->param,
 60				 STIH407_USB_PICOPHY_PARAM_MASK,
 61				 STIH407_USB_PICOPHY_PARAM_DEF);
 62	if (ret)
 63		return ret;
 64
 65	return reset_control_deassert(phy_dev->rstport);
 66}
 67
 68static int stih407_usb2_exit_port(struct phy *phy)
 69{
 70	struct stih407_usb2_picophy *phy_dev = phy_get_drvdata(phy);
 71
 72	/*
 73	 * Only port reset is asserted, phy global reset is kept untouched
 74	 * as other ports may still be active. When all ports are in reset
 75	 * state, assumption is made that power will be cut off on the phy, in
 76	 * case of suspend for instance. Theoretically, asserting individual
 77	 * reset (like here) or global reset should be equivalent.
 78	 */
 79	return reset_control_assert(phy_dev->rstport);
 80}
 81
 82static const struct phy_ops stih407_usb2_picophy_data = {
 83	.init = stih407_usb2_init_port,
 84	.exit = stih407_usb2_exit_port,
 85	.owner = THIS_MODULE,
 86};
 87
 88static int stih407_usb2_picophy_probe(struct platform_device *pdev)
 89{
 90	struct stih407_usb2_picophy *phy_dev;
 91	struct device *dev = &pdev->dev;
 92	struct device_node *np = dev->of_node;
 93	struct phy_provider *phy_provider;
 94	unsigned int syscon_args[2];
 95	struct phy *phy;
 96
 97	phy_dev = devm_kzalloc(dev, sizeof(*phy_dev), GFP_KERNEL);
 98	if (!phy_dev)
 99		return -ENOMEM;
100
101	phy_dev->dev = dev;
102	dev_set_drvdata(dev, phy_dev);
103
104	phy_dev->rstc = devm_reset_control_get_shared(dev, "global");
105	if (IS_ERR(phy_dev->rstc)) {
106		dev_err(dev, "failed to ctrl picoPHY reset\n");
107		return PTR_ERR(phy_dev->rstc);
108	}
109
110	phy_dev->rstport = devm_reset_control_get_exclusive(dev, "port");
111	if (IS_ERR(phy_dev->rstport)) {
112		dev_err(dev, "failed to ctrl picoPHY reset\n");
113		return PTR_ERR(phy_dev->rstport);
114	}
115
116	/* Reset port by default: only deassert it in phy init */
117	reset_control_assert(phy_dev->rstport);
118
119	phy_dev->regmap = syscon_regmap_lookup_by_phandle_args(np, "st,syscfg",
120							       2, syscon_args);
121	if (IS_ERR(phy_dev->regmap)) {
122		dev_err(dev, "No syscfg phandle specified\n");
123		return PTR_ERR(phy_dev->regmap);
124	}
125
126	phy_dev->param = syscon_args[PHYPARAM_REG];
127	phy_dev->ctrl = syscon_args[PHYCTRL_REG];
128
129	phy = devm_phy_create(dev, NULL, &stih407_usb2_picophy_data);
130	if (IS_ERR(phy)) {
131		dev_err(dev, "failed to create Display Port PHY\n");
132		return PTR_ERR(phy);
133	}
134
135	phy_dev->phy = phy;
136	phy_set_drvdata(phy, phy_dev);
137
138	phy_provider = devm_of_phy_provider_register(dev, of_phy_simple_xlate);
139	if (IS_ERR(phy_provider))
140		return PTR_ERR(phy_provider);
141
142	return 0;
143}
144
145static const struct of_device_id stih407_usb2_picophy_of_match[] = {
146	{ .compatible = "st,stih407-usb2-phy" },
147	{ /*sentinel */ },
148};
149
150MODULE_DEVICE_TABLE(of, stih407_usb2_picophy_of_match);
151
152static struct platform_driver stih407_usb2_picophy_driver = {
153	.probe = stih407_usb2_picophy_probe,
154	.driver = {
155		   .name = "stih407-usb-genphy",
156		   .of_match_table = stih407_usb2_picophy_of_match,
157		   }
158};
159
160module_platform_driver(stih407_usb2_picophy_driver);
161
162MODULE_AUTHOR("Giuseppe Cavallaro <peppe.cavallaro@st.com>");
163MODULE_DESCRIPTION("STMicroelectronics Generic picoPHY driver for STiH407");
164MODULE_LICENSE("GPL v2");