1// SPDX-License-Identifier: GPL-2.0
2/*
3 * ulpi.c - DesignWare USB3 Controller's ULPI PHY interface
4 *
5 * Copyright (C) 2015 Intel Corporation
6 *
7 * Author: Heikki Krogerus <heikki.krogerus@linux.intel.com>
8 */
9
10#include <linux/delay.h>
11#include <linux/time64.h>
12#include <linux/ulpi/regs.h>
13
14#include "core.h"
15#include "io.h"
16
17#define DWC3_ULPI_ADDR(a) \
18		((a >= ULPI_EXT_VENDOR_SPECIFIC) ? \
19		DWC3_GUSB2PHYACC_ADDR(ULPI_ACCESS_EXTENDED) | \
20		DWC3_GUSB2PHYACC_EXTEND_ADDR(a) : DWC3_GUSB2PHYACC_ADDR(a))
21
22#define DWC3_ULPI_BASE_DELAY	DIV_ROUND_UP(NSEC_PER_SEC, 60000000L)
23
24static int dwc3_ulpi_busyloop(struct dwc3 *dwc, u8 addr, bool read)
25{
26	unsigned long ns = 5L * DWC3_ULPI_BASE_DELAY;
27	unsigned int count = 10000;
28	u32 reg;
29
30	if (addr >= ULPI_EXT_VENDOR_SPECIFIC)
31		ns += DWC3_ULPI_BASE_DELAY;
32
33	if (read)
34		ns += DWC3_ULPI_BASE_DELAY;
35
36	reg = dwc3_readl(dwc->regs, DWC3_GUSB2PHYCFG(0));
37	if (reg & DWC3_GUSB2PHYCFG_SUSPHY)
38		usleep_range(1000, 1200);
39
40	while (count--) {
41		ndelay(ns);
42		reg = dwc3_readl(dwc->regs, DWC3_GUSB2PHYACC(0));
43		if (reg & DWC3_GUSB2PHYACC_DONE)
44			return 0;
45		cpu_relax();
46	}
47
48	return -ETIMEDOUT;
49}
50
51static int dwc3_ulpi_read(struct device *dev, u8 addr)
52{
53	struct dwc3 *dwc = dev_get_drvdata(dev);
54	u32 reg;
55	int ret;
56
57	reg = DWC3_GUSB2PHYACC_NEWREGREQ | DWC3_ULPI_ADDR(addr);
58	dwc3_writel(dwc->regs, DWC3_GUSB2PHYACC(0), reg);
59
60	ret = dwc3_ulpi_busyloop(dwc, addr, true);
61	if (ret)
62		return ret;
63
64	reg = dwc3_readl(dwc->regs, DWC3_GUSB2PHYACC(0));
65
66	return DWC3_GUSB2PHYACC_DATA(reg);
67}
68
69static int dwc3_ulpi_write(struct device *dev, u8 addr, u8 val)
70{
71	struct dwc3 *dwc = dev_get_drvdata(dev);
72	u32 reg;
73
74	reg = DWC3_GUSB2PHYACC_NEWREGREQ | DWC3_ULPI_ADDR(addr);
75	reg |= DWC3_GUSB2PHYACC_WRITE | val;
76	dwc3_writel(dwc->regs, DWC3_GUSB2PHYACC(0), reg);
77
78	return dwc3_ulpi_busyloop(dwc, addr, false);
79}
80
81static const struct ulpi_ops dwc3_ulpi_ops = {
82	.read = dwc3_ulpi_read,
83	.write = dwc3_ulpi_write,
84};
85
86int dwc3_ulpi_init(struct dwc3 *dwc)
87{
88	/* Register the interface */
89	dwc->ulpi = ulpi_register_interface(dwc->dev, &dwc3_ulpi_ops);
90	if (IS_ERR(dwc->ulpi)) {
91		dev_err(dwc->dev, "failed to register ULPI interface");
92		return PTR_ERR(dwc->ulpi);
93	}
94
95	return 0;
96}
97
98void dwc3_ulpi_exit(struct dwc3 *dwc)
99{
100	if (dwc->ulpi) {
101		ulpi_unregister_interface(dwc->ulpi);
102		dwc->ulpi = NULL;
103	}
104}
105