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
32 struct 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
stih407_usb2_pico_ctrl(struct stih407_usb2_picophy * phy_dev)42 static 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
stih407_usb2_init_port(struct phy * phy)51 static 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
stih407_usb2_exit_port(struct phy * phy)68 static 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
82 static 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
stih407_usb2_picophy_probe(struct platform_device * pdev)88 static 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
145 static const struct of_device_id stih407_usb2_picophy_of_match[] = {
146 { .compatible = "st,stih407-usb2-phy" },
147 { /*sentinel */ },
148 };
149
150 MODULE_DEVICE_TABLE(of, stih407_usb2_picophy_of_match);
151
152 static 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
160 module_platform_driver(stih407_usb2_picophy_driver);
161
162 MODULE_AUTHOR("Giuseppe Cavallaro <peppe.cavallaro@st.com>");
163 MODULE_DESCRIPTION("STMicroelectronics Generic picoPHY driver for STiH407");
164 MODULE_LICENSE("GPL v2");
165