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(base: dwc->regs, DWC3_GUSB2PHYCFG(0));
37 if (reg & DWC3_GUSB2PHYCFG_SUSPHY)
38 usleep_range(min: 1000, max: 1200);
39
40 while (count--) {
41 ndelay(ns);
42 reg = dwc3_readl(base: 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(base: dwc->regs, DWC3_GUSB2PHYACC(0), value: reg);
59
60 ret = dwc3_ulpi_busyloop(dwc, addr, read: true);
61 if (ret)
62 return ret;
63
64 reg = dwc3_readl(base: 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(base: dwc->regs, DWC3_GUSB2PHYACC(0), value: reg);
77
78 return dwc3_ulpi_busyloop(dwc, addr, read: 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(ptr: dwc->ulpi)) {
91 dev_err(dwc->dev, "failed to register ULPI interface");
92 return PTR_ERR(ptr: 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

source code of linux/drivers/usb/dwc3/ulpi.c